The red planet Mars, named for the Roman god of war, has long been an omen in the night sky. And in its own way, the planets rusty red surface tells a story of destruction. Billions of years ago, the fourth planet from the sun could have been mistaken for Earths smaller twin, with liquid water on its surfaceand maybe even life.

Now, the world is a cold, barren desert with few signs of liquid water. But after decades of study using orbiters, landers, and rovers, scientists have revealed Mars as a dynamic, windblown landscape that couldjust maybeharbor microbial life beneath its rusty surface even today.

With a radius of 2,106 miles, Mars is the seventh largest planet in our solar system and about half the diameter of Earth. Its surface gravity is 37.5 percent of Earths.

Mars 101

Recent NASA exploratory expeditions revealed some of the red planet's biggest mysteries. This video explains what makes it so different from Earth and what would happen if humans lived there.

Mars rotates on its axis every 24.6 Earth hours, defining the length of a Martian day, which is called a sol (short for solar day). Marss axis of rotation is tilted 25.2 degrees relative to the plane of the planets orbit around the sun, which helps give Mars seasons similar to those on Earth. Whichever hemisphere is tilted closer to the sun experiences spring and summer, while the hemisphere tilted away gets fall and winter. At two specific moments each yearcalled the equinoxesboth hemispheres receive equal illumination.

But for several reasons, seasons on Mars are different from those on Earth. For one, Mars is on average about 50 percent farther from the sun than Earth is, with an average orbital distance of 142 million miles. This means that it takes Mars longer to complete a single orbit, stretching out its year and the lengths of its seasons. On Mars, a year lasts 669.6 sols, or 687 Earth days, and an individual season can last up to 194 sols, or just over 199 Earth days.

The angle of Marss axis of rotation also changes much more often than Earth's, which has led to swings in the Martian climate on timescales of thousands to millions of years. In addition, Marss orbit is less circular than Earths, which means that its orbital velocity varies more over the course of a Martian year. This annual variation affects the timing of the red planets solstices and equinoxes. On Mars, the northern hemispheres spring and summer are longer than the fall and winter.

Theres another complicating factor: Mars has a far thinner atmosphere than Earth, which dramatically lessens how much heat the planet can trap near its surface. Surface temperatures on Mars can reach as high as 70 degrees Fahrenheit and as low as -225 degrees Fahrenheit, but on average, its surface is -81 degrees Fahrenheit, a full 138 degrees colder than Earths average temperature.

The primary driver of modern Martian geology is its atmosphere, which is mostly made of carbon dioxide, nitrogen, and argon. By Earth standards, the air is preposterously thin; air pressure atop Mount Everest is about 50 times higher than it is at the Martian surface. Despite the thin air, Martian breezes can gust up to 60 miles an hour, kicking up dust that fuels huge dust storms and massive fields of alien sand dunes.

Once upon a time, though, wind and water flowed across the red planet. Robotic rovers have found clear evidence that billions of years ago, lakes and rivers of liquid water coursed across the red planets surface. This means that at some point in the distant past, Marss atmosphere was sufficiently dense and retained enough heat for water to remain liquid on the red planets surface. Not so today: Though water ice abounds under the Martian surface and in its polar ice caps, there are no large bodies of liquid water on the surface there today.

Mars also lacks an active plate tectonic system, the geologic engine that drives our active Earth, and is also missing a planetary magnetic field. The absence of this protective barrier makes it easier for the suns high-energy particles to strip away the red planets atmosphere, which may help explain why Marss atmosphere is now so thin. But in the ancient pastup until about 4.12 to 4.14 billion years agoMars seems to have had an inner dynamo powering a planet-wide magnetic field. What shut down the Martian dynamo? Scientists are still trying to figure out.

Like Earth and Venus, Mars has mountains, valleys, and volcanoes, but the red planets are by far the biggest and most dramatic. Olympus Mons, the solar systems largest volcano, towers some 16 miles above the Martian surface, making it three times taller than Everest. But the base of Olympus Mons is so widesome 374 miles acrossthat the volcanos average slope is only slightly steeper than a wheelchair ramp. The peak is so massive, it curves with the surface of Mars. If you stood at the outer edge of Olympus Mons, its summit would lie beyond the horizon.

Mars has not only the highest highs, but also some of the solar systems lowest lows. Southeast of Olympus Mons lies Valles Marineris, the red planets iconic canyon system. The gorges span about 2,500 miles and cut up to 4.3 miles into the red planets surface. The network of chasms is four times deeperand five times longerthan Earths Grand Canyon, and at its widest, its a staggering 200 miles across. The valleys get their name from Mariner 9, which became the first spacecraft to orbit another planet when it arrived at Mars in 1971.

About 4.5 billion years ago, Mars coalesced from the gaseous, dusty disk that surrounded our young sun. Over time, the red planets innards differentiated into a core, a mantle, and an outer crust thats an average of 40 miles thick.

Its core is likely made of iron and nickel, like Earths, but probably contains more sulfur than ours. The best available estimates suggest that the core is about 2,120 miles across, give or take 370 milesbut we dont know the specifics. NASAs InSight lander aims to unravel the mysteries of Marss interior by tracking how seismic waves move through the red planet.

Marss northern and southern hemispheres are wildly different from one another, to a degree unlike any other planet in the solar system. The planets northern hemisphere consists mostly of low-lying plains, and the crust there can be just 19 miles thick. The highlands of the southern hemisphere, however, are studded with many extinct volcanoes, and the crust there can get up to 62 miles thick.

What happened? Its possible that patterns of internal magma flow caused the difference, but some scientists think it's the result of Mars suffering one or several major impacts. One recent model suggests Mars got its two faces because an object the size of Earths moon slammed into Mars near its south pole.

Both hemispheres do have one thing in common: Theyre covered in the planets trademark dust, which gets its many shades of orange, red, and brown from iron rust.

At some point in the distant past, the red planet gained its two small and irregularly shaped moons, Phobos and Deimos. The two lumpy worlds, discovered in 1877, are named for the sons and chariot drivers of the god Mars in Roman mythology. How the moons formed remains unsolved. One possibility is that they formed in the asteroid belt and were captured by Marss gravity. But recent models instead suggest that they could have formed from the debris flung up from Mars after a huge impact long ago.

Deimos, the smaller of the two moons, orbits Mars every 30 hours and is less than 10 miles across. Its larger sibling Phobos bears many scars, including craters and deep grooves running across its surface. Scientists have long debated what caused the grooves on Phobos. Are they tracks left behind by boulders rolling across the surface after an ancient impact, or signs that Marss gravity is pulling the moon apart?

Either way, the moons future will be considerably less groovy. Each century, Phobos gets about six feet closer to Mars; in 50 million years or so, the moon is projected either to crash into the red planets surface or break into smithereens.

Since the 1960s, humans have robotically explored Mars more than any other planet beyond Earth. Currently, eight missions from the U.S., European Union, Russia, and India are actively orbiting Mars or roving across its surface. But getting safely to the red planet is no small feat. Of the 45 Mars missions launched since 1960, 26 have had some component fail to leave Earth, fall silent en route, miss orbit around Mars, burn up in the atmosphere, crash on the surface, or die prematurely.

More missions are on the horizon, including some designed to help search for Martian life. NASA is building its Mars 2020 rover to cache promising samples of Martian rock that a future mission would return to Earth. In 2020, the European Space Agency and Roscosmos plan to launch a rover named for chemist Rosalind Franklin, whose work was crucial to deciphering the structure of DNA. The rover will drill into Martian soil to hunt for signs of past and present life. Other countries are joining the fray, making space exploration more global in the process. In July 2020, the United Arab Emirates is slated to launch its Hope orbiter, which will study the Martian atmosphere.

Perhaps humans will one day join robots on the red planet. NASA has stated its goal to send humans back to the moon as a stepping-stone to Mars. Elon Musk, founder and CEO of SpaceX, is building a massive vehicle called Starship in part to send humans to Mars. Will humans eventually build a scientific base on the Martian surface, like those that dot Antarctica? How will human activity affect the red planet or our searches for life there?

Time will tell. But no matter what, Mars will continue to occupy the human imagination, a glimmering red beacon in our skies and stories.

Originally posted here:

Mars, the red planet: Facts and information

Mars, fourth planet in the solar system in order of distance from the Sun and seventh in size and mass. It is a periodically conspicuous reddish object in the night sky. Mars is designated by the symbol .

An especially serene view of Mars (Tharsis side), a composite of images taken by the Mars Global Surveyor spacecraft in April 1999. The northern polar cap and encircling dark dune field of Vastitas Borealis are visible at the top of the globe. White water-ice clouds surround the most prominent volcanic peaks, including Olympus Mons near the western limb, Alba Patera to its northeast, and the line of Tharsis volcanoes to the southeast. East of the Tharsis rise can be seen the enormous near-equatorial gash that marks the canyon system Valles Marineris.

Britannica Quiz

Astronomy and Space Quiz

What makes a planet a dwarf planet? How many miles are in a light-year? What exactly is a quasar? Launch into other worlds while testing your knowledge about space, celestial bodies, and the solar system.

Sometimes called the Red Planet, Mars has long been associated with warfare and slaughter. It is named for the Roman god of war. As long as 3,000 years ago, Babylonian astronomer-astrologers called the planet Nergal for their god of death and pestilence. The planets two moons, Phobos (Greek: Fear) and Deimos (Terror), were named for two of the sons of Ares and Aphrodite (the counterparts of Mars and Venus, respectively, in Greek mythology).

In recent times Mars has intrigued people for more-substantial reasons than its baleful appearance. The planet is the second closest to Earth, after Venus, and it is usually easy to observe in the night sky because its orbit lies outside Earths. It is also the only planet whose solid surface and atmospheric phenomena can be seen in telescopes from Earth. Centuries of assiduous studies by earthbound observers, extended by spacecraft observations since the 1960s, have revealed that Mars is similar to Earth in many ways. Like Earth, Mars has clouds, winds, a roughly 24-hour day, seasonal weather patterns, polar ice caps, volcanoes, canyons, and other familiar features. There are intriguing clues that billions of years ago Mars was even more Earth-like than today, with a denser, warmer atmosphere and much more waterrivers, lakes, flood channels, and perhaps oceans. By all indications Mars is now a sterile frozen desert. However, close-up images of dark streaks on the slopes of some craters during Martian spring and summer suggest that at least small amounts of water may flow seasonally on the planets surface, and radar reflections from a possible lake under the south polar cap suggest that water may still exist as a liquid in protected areas below the surface. The presence of water on Mars is considered a critical issue because life as it is presently understood cannot exist without water. If microscopic life-forms ever did originate on Mars, there remains a chance, albeit a remote one, that they may yet survive in these hidden watery niches. In 1996 a team of scientists reported what they concluded to be evidence for ancient microbial life in a piece of meteorite that had come from Mars, but most scientists have disputed their interpretation.

Since at least the end of the 19th century, Mars has been considered the most hospitable place in the solar system beyond Earth both for indigenous life and for human exploration and habitation. At that time, speculation was rife that the so-called canals of Marscomplex systems of long, straight surface lines that very few astronomers had claimed to see in telescopic observationswere the creations of intelligent beings. Seasonal changes in the planets appearance, attributed to the spread and retreat of vegetation, added further to the purported evidence for biological activity. Although the canals later proved to be illusory and the seasonal changes geologic rather than biological, scientific and public interest in the possibility of Martian life and in exploration of the planet has not faded.

During the past century Mars has taken on a special place in popular culture. It has served as inspiration for generations of fiction writers from H.G. Wells and Edgar Rice Burroughs in the heyday of the Martian canals to Ray Bradbury in the 1950s and Kim Stanley Robinson in the 90s. Mars has also been a central theme in radio, television, and film, perhaps the most notorious case being Orson Welless radio-play production of H.G. Wellss novel War of the Worlds, which convinced thousands of unwitting listeners on the evening of October 30, 1938, that beings from Mars were invading Earth. The planets mystique and many real mysteries remain a stimulus to both scientific inquiry and human imagination to this day.

Read the original post:

Mars | Facts, Surface, Temperature, & Atmosphere | Britannica

Perseverance, NASAs latest rover, landed on Mars in February with a mission to answer questions about the past and future of life on the Red Planet.

Over the course of that mission lasting nearly two years, or one Martian year the rover will conduct research using a range of instruments designed to probe the planets landscape for glimpses into its ancient past.

Researchers hope to gain a better sense of whether primordial life once existed on our celestial neighbor (and if so, where and when), and how technology may pave the way for astronauts to sustain their own lives during future voyages to its now-desolate surface.

In a few short months, the rover and its companions have achieved massive technological feats and uncovered a trove of meaningful data and fascinating photos. Perseverance has already overseen the successful demonstration of two pieces of experimental technology a small helicopter named Ingenuity and a toaster-sized contraption called MOXIE that converts Marss carbon dioxide-heavy atmosphere into oxygen.

The rover is stationed in Marss Jezero Crater, which researchers believe was home to a lake more than 3.5 billion years ago. Researchers back home have been rolling out software updates and checking out the highly autonomous vehicles accessories. Over the next few weeks, Perseverance will begin evaluating local geology in search of rock samples that may hold important clues.

Ultimately, the hope is that a future mission can pull off the complicated task of transporting a cache of those samples to Earth for further study. (That plan is still a proposal for now, and hasnt yet been signed off on by NASA.)

Its been an eventful first few months for Perseverance, its technological companions and the hundreds of researchers who monitor and operate them here on Earth. Heres a look at what they have accomplished, and whats next for the mission.

In NASAs Mars mission, MOXIE means more than spunk and determination it stands for Mars Oxygen In-Situ Resource Utilization Experiment (in-situ means in place). In April, the pint-sized piece of tech achieved its goal of extracting oxygen from the Martian atmosphere.

Pulling carbon dioxide from the atmosphere and splitting it into carbon monoxide and oxygen, the device produced about 5 grams of oxygen, roughly enough for an astronaut to breathe for 10 minutes.

During the missions first year, MOXIE will perform that demonstration up to 10 times. The density of the planets atmosphere changes dramatically depending on factors like whether its night or day which significantly influences temperature as well as which season it is. Researchers aim to determine whether it will work in those varying conditions.

The basic idea is to produce oxygen during all seasons, during all times of day, and thats the plan, said Jeffrey Hoffman, a former astronaut and current deputy principal investigator of the MOXIE experiment.

An air pump pulls in carbon dioxide gas from the Martian atmosphere, which is then regulated and fed to the Solid OXide Electrolyzer (SOXE), where it is electrochemically split to produce pure oxygen. Credit: NASA/JPL-Caltech

If future generations of MOXIE ever accompany astronauts on trips to Mars, the machine will have to be equipped to run at all times the existing MOXIE must be turned on and allowed to heat up to about 1,400 degrees Fahrenheit ahead of each demonstration and automatically calibrate itself to safely convert atmosphere at any density.

One of the purposes of MOXIE is not just to demonstrate that it works, but to learn enough about the whole system so that we can actually help inform the design of a much larger scale autonomous oxygen producing system, which is the ultimate goal of this whole enterprise, Hoffman said.

A crew of six astronauts sustaining themselves on Mars for two or so years would need maybe a ton of oxygen, he added. The rocket theyd rely on to lift them off Mars and return them home would need about 25 to 30 times as much oxygen to fire up.

Sending all of that oxygen with any given mission would be a monumental and expensive feat. If you can produce the oxygen you need on Mars instead of lugging it there, youre way ahead of the game, Hoffman said.

The Ingenuity helicopter is the first remotely controlled aircraft to successfully take flight on a planet other than our own.

This mission makes a huge difference in showing its not just a dream, said Havard Grip, who serves as Ingenuitys chief pilot and flight control lead. This is reality.

Five test flights were planned for Ingenuity, each planned to be a little bit farther or faster than the one before it. The experiment was such a resounding success that Ingenuity keeps taking to the air.

During its sixth flight, an error occurred for the first time: One of images that Ingenuity regularly takes to orient itself was lost, meaning that each subsequent image had an inaccurate timestamp. That confused the helicopters system, Grip explained. It began trying to correct things that werent really errors, which impacted the algorithm thats used to keep Ingenuity stable and under control.

Fortunately, NASA engineers designed the helicopter to account for timing errors, so Ingenuity was able to complete a safe landing.

This obstacle, an unknown unknown challenge, as researchers sometimes put it, offered a kind of stress test, which Ingenuity passed handily.

We were extremely pleased with how everything has been performing up until this point, Grip said. And really that can be said for flight six, too, in many ways.

This black-and-white image was taken by the navigation camera aboard NASAs Ingenuity helicopter during its third flight, on April 25, 2021. Credit: NASA/JPL-Caltech

Plans for flight seven involve sending the helicopter around 350 feet south of where it now sits, and will be the second time Ingenuity will land at an airfield that it did not survey from the air during a previous flight, according to NASA. Researchers are confident that this location is relatively flat and has few surface obstructions based on images captured by NASAs Mars Reconnaissance Orbiter.

Ingenuitys performance so far has generated mountains of useful data, Grip said, especially regarding how the helicopter itself has behaved in real-life conditions on Mars. Much like MOXIE, that information will be invaluable when it comes to engineering future generations of comparable technology.

Grip emphasized that theres no expectation that anything Ingenuity does from here on out will help Perseverance achieve its goals, but any useful information it can offer is a kind of welcome bonus. He noted that aerial images Ingenuity snapped during a recent flight may be of interest to the researchers who work on Perseverance.

Ingenuitys time is expected to wrap up at some point this August, after which point it will be left behind. Until then, it will remain in the general vicinity of Perseverance, which serves as a kind of communication hub that connects it to researchers on Earth.

Regardless of what becomes of Ingenuity, the helicopter has already achieved an objectively impressive goal. We actually have an operating helicopter on Mars, and its doing its job fabulously, Grip said.

After many Martian days, called sols, of supporting these tech demonstrations and having its myriad tools and accessories meticulously evaluated by researchers back home, Perseverance is ready to kick off its own scientific journey.

The team on Earth has been transmitting software updates that enable crucial features, like improving the rovers navigation system so that its able to map and avoid any hazards that are in the way of its predetermined path.

Perseverance was built with very smart, very autonomous software, said Jennifer Trosper, deputy project manager at NASAs Jet Propulsion Laboratory. But rather than put all of its bells and whistles into action upon arrival, researchers instead took a more cautious approach that involved taking baby steps to make sure everything was working properly.

So far, the rover is looking good and is expected to collect its first samples in late June or early July, once researchers can confirm key capabilities, like its auto-navigation and final sampling systems, are in order.

Perseverance is expected to pick up four times as many samples as did Curiosity, NASAs previous rover. The rover is more advanced than its predecessor, which allows it to get more done in less time and with more autonomy.

We have to be faster. We have to be more efficient. We have to drive to locations much more quickly, Trosper said. So thats what these things are enabling us to do.

At the moment, Perseverance is residing in one of the oldest parts of the lake bed that Jezero Crater once housed a lucky accident resulting from the rover landing a bit off its intended target. Its possible that the rover never would have made it to this particularly aged spot otherwise, Trosper noted.

The ancient, exposed terrain, which lies to the east of a nearby sand dune field, may offer some of the oldest samples Perseverance gets on its mission.

When it comes to geological sampling, older is better because, Trosper explained, geology is just layers of information that tells you what happens over time. Samples from this location should help answer questions about the farthest reaches of Jezeros primordial past.

Being able to get samples from this very old part of the crater is really important to making the whole story fit together, she added. Its a significant piece of the puzzle.

Perseverance is equipped with tools that will allow researchers to examine the rocks it comes across and determine which ones are worth sampling. When faced with a rock of interest, Perseverances drill can use one bit to abrade, or gently shave down, part of its surface, and another to blow a puff of air that removes the resulting dust. The rovers remote science instruments can then determine the elemental composition of the rock itself, and what information it might hold.

Sedimentary rocks are particularly useful in the lakebed because theyre more likely to have captured evidence or biosignatures of ancient life, if any ever existed there.

Igneous rocks, according to NASA, act as geological clocks that can help researchers map a more precise timeline of how the local landscape formed billions of years ago.

For Trosper, Perseverances high-tech capabilities are just as exciting as the mysteries its set out to solve.

Obviously the science itself is phenomenal, because this is the best place on Mars to look for evidence of ancient microbial life, and were here, Trosper said. But the [rovers] autonomy is also one of the hallmarks of this mission that I really am excited about.

Go here to see the original:

How NASA is hunting for signs of life on Mars - PBS NewsHour

This before and after set of images shows the landing site of the Zhurong rover in Utopia Planitia on Mars. The rover is the smaller of the two dots in the upper right-hand corner.

There's a long tradition of orbiting spacecraft looking down on Mars and picking out the tiny machines on the surface below. The latest entry in this lineage comes from China's Tianwen-1 mission. The orbiter snapped a picture of the Zhurong rover and its lander on June 2.

The China National Space Administration shared a look at the landing zone in Utopia Planitia, a broad plains region, on Monday. China is only the second nation to operate a rover on Mars, after the US.

From the lab to your inbox. Get the latest science stories from CNET every week.

The rover and lander can be seen as small specks near each other in the top right-hand side of the image. Zhurong is the lower of the two dots. The other notable spots are where parts of the landing system, including the parachute and heat shield, landed.

The Zhurong rover is the smaller dot just below the lander.

"The dark area surrounding the landing platform might be caused by the influence of the engine plume during landing," CNSA said in a statement. "The symmetrical bright stripes in the north-south direction of the landing platform might be from fine dust when the landing platform emptied the remaining fuel after landing."

Images from the Tianwen-1 mission -- which consists of the spacecraft, the lander and the rover -- have been few and far between. Most recently in late May, we saw some wheel tracks left by the rover's first moves across the dusty and rocky ground.

The solar-powered rover has been rolling since May 22 and has an expected life span of around three months. It's gathering images of the surface and studying the planet's subsurface as it looks for signs of ice below.

CNSA doesn't typically release as much information on its space exploits as we're used to seeing from agencies like NASA and the European Space Agency, so tidbits like the orbital images give us an enticing glimpse into the mission.

FollowCNET's 2021 Space Calendarto stay up to date with all the latest space news this year. You can even add it to your own Google Calendar.

More here:

China's Mars rover spotted on the surface by orbiting spacecraft - CNET

SAVANNAH, Ga (WSAV) The Curiosity Rover captures pictures of the Martian skyline and atmosphere every day. However in late May, Curiosity captured rare clouds in the sky using its in color Mast camera. These types of clouds dont occur that often in the very thin and dry atmosphere. Most clouds are typically found at the Planets equator when Mar is farthest from the Sun.

Two Earth years ago, NASA scientists noticed clouds forming earlier than expected. They made sure Curiosity would be set up to start documenting these rare clouds as soon as they appeared in January. The Rover captured images of wispy clouds of ice crystals.

Most Martian clouds are no higher than about 37 miles in the sky and are made of water ice. These rare clouds are at higher altitudes, at colder temperatures, and are most likely made of frozen carbon dioxide.

The Curiosity team was able to pin point the height of the rare clouds by following the position of the sun in the sky and the color of the Noctilucent clouds. The high level clouds glowed brighter as the sun was high in the sky. As the sun began to drop below their altitude, the ice crystals would darken. This is one useful way they can determine how high the clouds are.

Another cool discovery NASA found by looking at these rare clouds is that they have a pastel shimmer to them when the sun is at certain positions. These are called Mother of Pearl clouds. They tend to have a light colorful shimmer like a pearl would have. The shimmer comes from the cloud particles growing at the same rate and growing to the same size.

NASA scientists were able to solve the mystery of what is creating a long stream of thin clouds coming from a now-existent volcano. Arsia Mons is south of the Martian equator. These mysterious clouds formed seasonally during spring and summer morning due to the combination of orographic lift of the existent volcanos height (12 miles tall) and meteorological conditions.

For comparison, Mount Everest is only about 5 1/2 miles tall. The spring and summer morning weather conditions plus the height also explains why the clouds would dissipate by midday. Much like how morning fog can form here on Earth but clear by midday.

The flowing cloud formation can stretch as long as 1,100 miles and around 93 miles wide. The Mars Express Visual Monitoring Camera caught the formation on the Red Planet. The images from the camera showed the clouds forming every spring and summer morning.

Follow this link:

WSAV NOW Weather: Rare clouds spotted on Mars - WSAV-TV

Pasadena, CA On June 1st, NASAs Perseverance Mars rover kicked off the science phase of its mission by leaving the Octavia E. Butler landing site. Until recently, the rover has been undergoing systems tests, or commissioning, and supporting the Ingenuity Mars Helicopters month of flight tests.

During the first few weeks of this first science campaign, the mission team will drive to a low-lying scenic overlook from which the rover can survey some of the oldest geologic features in Jezero Crater, and theyll bring online the final capabilities of the rovers auto-navigation and sampling systems.

By the time Perseverance completed its commissioning phase on June 1st, the rover had already tested its oxygen-generating MOXIE instrument and conducted the technology demonstration flights of the Ingenuity helicopter. Its cameras had taken more than 75,000 images, and its microphones had recorded the first audio soundtracks of Mars.

We are putting the rovers commissioning phase as well as the landing site in our rearview mirror and hitting the road, said Jennifer Trosper, Perseverance project manager at NASAs Jet Propulsion Laboratory in Southern California.

Over the next several months, Perseverance will be exploring a 1.5-square-mile [4-square-kilometer] patch of the crater floor. It is from this location that the first samples from another planet will be collected for return to Earth by a future mission, Trosper stated.

The science goals of the mission are to study the Jezero region in order to understand the geology and past habitability of the environment in the area, and to search for signs of ancient microscopic life. The team will identify and collect the most compelling rock and sediment samples, which a future mission could retrieve and bring back to Earth for more detailed study.

Perseverance will also take measurements and test technologies to support the future human and robotic exploration of Mars.

This image looking west toward the Stah geologic unit on Mars was taken from the height of 33 feet (10 meters) by NASAs Ingenuity Mars helicopter during its sixth flight, on May 22, 2021. (NASA/JPL-Caltech)

Spanning hundreds of sols (or Martian days), this first science campaign will pursue all of the missions science goals as the rover explores two unique geologic units in which Jezeros deepest (and most ancient) layers of exposed bedrock and other intriguing geologic features can be found.

The first unit, called the Crater Floor Fractured Rough, is the crater-filled floor of Jezero. The adjacent unit, named Stah (meaning amidst the sand in the Navajo language), has its fair share of Mars bedrock but is also home to ridges, layered rocks, and sand dunes.

To do justice to both units in the time allotted, the team came up with the Martian version of an old auto club-style map, said JPLs Kevin Hand, an astrobiologist and co-lead, along with Vivian Sun, of this science campaign. We have our route planned, complete with optional turnoffs and labeled areas of interest and potential obstructions in our path.

Most of the challenges along the way are expected to come in the form of sand dunes located within the mitten-shaped Stah unit. To negotiate them, the rover team decided Perseverance will drive mostly either on the Crater Floor Fractured Rough or along the boundary line between it and Stah. When the occasion calls for it, Perseverance will perform a toe dip into the Stah unit, making a beeline for a specific area of interest.

The goal of the campaign is to establish what four locations in these units best tell the story of Jezero Craters early environment and geologic history. When the science team decides a location is just right, they will collect one or two samples.

This annotated image of Jezero Crater depicts the routes for Perseverances first science campaign (yellow hash marks) as well as its second (light-yellow hash marks). (NASA/JPL-Caltech/University of Arizona)

Starting with the Crater Floor Fractured Rough and Seitah geologic units allows us to start our exploration of Jezero at the very beginning, said Hand. This area was under at least 100 meters [328 feet] of water 3.8 billion years ago. We dont know what stories the rocks and layered outcrops will tell us, but were excited to get started.

The first science campaign will be complete when the rover returns to its landing site. At that point, Perseverance will have traveled between 1.6 and 3.1 miles (2.5 and 5 kilometers) and up to eight of Perseverances 43 sample tubes could be filled with Mars rock and regolith (broken rock and dust).

Next, Perseverance will travel north then west toward the location of its second science campaign: Jezeros delta region. The delta is the fan-shaped remains of the confluence of an ancient river and a lake within Jezero Crater. The location may be especially rich in carbonates minerals that, on Earth, can preserve fossilized signs of ancient life and can be associated with biological processes.

From Sojourner to Spirit and Opportunity to Curiosity to Perseverance, Matt has played key roles in the design, construction, and operations of every Mars rover NASA has ever built, said Trosper. And while the project is losing a great leader and trusted friend, we know Matt will continue making great things happen for the planetary science community.

A key objective for NASAs Perseverance Mars Rovers mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planets geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith.

Subsequent NASA missions, in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 Perseverance mission is part of NASAs Moon to Mars exploration approach, which includes Artemis missions to the Moon that will help prepare for human exploration of the Red Planet.

JPL, which is managed for NASA by Caltech in Pasadena, California, built and manages operations of the Perseverance rover.

For more about Perseverance:

mars.nasa.gov/mars2020/

nasa.gov/perseverance

See original here:

NASA's Perseverance Mars Rover heads south to search for Signs of Life in Jezero Crater's Lakebed - Clarksville, TN Online - Clarksville Online

This image was taken by Left Navigation Camera onboard NASA's Mars rover Curiosity on Sol 3140. Credits: NASA/JPL-Caltech Download image

Another successful long drive brought us to another wondrous workspace, filled with textures and structures the team could not wait to explore. The engineers made it possible to get the arm to two targets for MAHLI and APXS analyses. The first, Minzac, is a small area of bedrock relatively free of veins and nodules. The second, Terrasson Lavilledieu, which in France is home to The Garden of the Imagination (a contemporary public park designed to represent the history of gardens), is a patch of gray vein material opportunistically lying flat for easy arm access. This vein material was sufficiently interesting to the team that it will also be the subject of Mastcam multispectral and ChemCam passive observations at the target Videix. Videix and Terrasson Lavilledieu are in very close proximity on the vein target, unlike their counterparts in France.

ChemCam will shoot across a nodule and bedrock at the target Vayres, and Mastcam will get another multispectral observation at this same target. The mid- and farfield terrain was as interesting as our workspace, and garnered imaging attention from both Mastcam and ChemCam. Mastcam will acquire a small mosaic of Larzac, a three dimensional jumble of intersecting veins standing up above the bedrock, a ten-image mosaic of the foot of a ridge extending down from higher on Mount Sharp, and a larger mosaic stretching from the workspace along the starboard side of the rover. ChemCam will acquire a long distance RMI mosaic of a butte in the sulfate unit many kilometers up the road from our current position.

As we sit at our current workspace, as we drive to our next one, and after we arrive there, DAN will ping the ground beneath the back wheels of the rover, tracking the H signal within the subsurface. RAD and REMS run regularly throughout the plan, continuing to build their steady records of the radiation and weather conditions in Gale. Navcam will acquire dust devil and cloud movies on the first sol of the plan, and both Navcam and Mastcam will measure the amount of dust in the atmosphere with images on second sol of the plan.

Go here to see the original:

Sols 3142-3143: Workspace of the Imagination NASA's Mars Exploration Program - NASA Mars Exploration

Light Perpetual starts with a description of a V2 about to explode on a Saturday in 1944. The tone is one of uneasy technological rapture: a thread-wide front of change propagating outward from the electric detonator, through the heavy mass of amatol. Francis Spufford has written about rockets before, in his non-fiction, engaging imaginatively with the Russian space race in Red Plenty and playing the V2 campaign at least partly for comedy in Backroom Boys, where he assessed the impact on morale of the V2 in Lowestoft. It was nil: thanks to the inaccuracy of the weapons sent against them, the people of Lowestoft had no idea they were targets.

Here the point of impact (target is exactly the wrong word for so approximate a missile) is a crowded Woolworths in South-East London. The place and time correspond with a particularly terrible missile strike on New Cross on 25 November 1944. The novel is a sort of counter-history, imagining that five of the children killed on that day escaped unharmed, and charting the lives that they might have gone on to lead. Although Spufford makes clear in his acknowledgments that the book is partly written in memory of the children who died in the New Cross attack, he also insists that Alec, Vern, Jo, Val and Ben are invented souls without real-life counterparts, just as Bexford the fictional London borough in which the novel is set is not New Cross.

The children are unprivileged rather than underprivileged and the narrative chronicles a range of opportunities for this socially homogenous group one that earlier generations could hardly have imagined. There is sociological truth to this, though theres also the sense of a writer trying to bring as much of the world as possible into a book that is remarkably ambitious for its size. The twin girls, Jo and Val, lead almost caricaturally contrasting lives, determined at least in part by their different reactions to growing up in a family without men. Jo savours her independence while Val is mesmerised and then entrapped by a masculinity that turns out to be almost purely toxic. Jo has a career as a backing singer for a British pop star who has made it big in the United States, an ex-lover with whom her connection is never quite broken. She doesnt have the push to turn herself into a solo artist, but enjoys the consolation prize of a little house with its own little crease in the hillside filled with the deep green shade of pines and succulents, bamboo and yucca: the California green that can make you forget the California brown all around it. Of all the books characters, Jo makes the most determined attempt to escape the pull of London, and it doesnt last. Val, meanwhile, never thinks of leaving, and acts as a sort of den mother to a group of racist thugs, some of them all too sincere in their belief in their mission and in her man, Mike, the only beautiful thing in her life, as well as being the cause of all the ugly ones.

To choose a group for its representative quality, its ordinariness, implies a recognition of individual limitation. But fiction chafes against ordinariness. Jo has the advantage an advantage in a novel at least of synaesthesia, with sounds bleeding into colours in her head: Under the bridge at the streets end a train rushes by: a scuffing of rust brown at the hushs edge, and then a long feathering liquid streak of purple across it. Theres no danger of Jo herself lacking colour. Ben, an outsider in the book partly by virtue of being the youngest, has his visual perceptions rendered with at least as much intensity. The first time he goes to a football match, aged seven, his gaze strays upwards:

With all this noisy air open round him Ben follows the brightness up, and up. He sees the London smoke is only a footstool. Above, the rain as it leaves mounts in a curving wall, immense, slate grey, slate purple. An anvil, pulling back. At the very top, it cauliflowers. It goes to bumps and lumps and smoothed-out tiny battlements too complicated for your eyes, but all crisp and clear.

Even in his first appearance, on the day of the V2 detonation that the book cancels, he is described as looking slightly mazed, as usual. He cant be more than two. His later history suggests a predisposition to obsessive thoughts and, as at the football match, he is always shifting his focus away from the world around him. He doesnt notice the goal that everyone else is cheering, dwelling instead on the point of gold the ball made when the sun caught it as it flew its an epiphany or a seizure or a bit of both. The conventions in play are similar to those in Updikes Rabbit books, where the protagonists lack of large-mindedness does not prevent Updike from imagining him largely, as Roger Sale put it in the New York Times, though they are stretched when very literary formulations are meant to be Bens unspoken words: Each tree stands in a ragged oval of leaf-fall, summers discarded yellow petticoat. This seems too sharply eloquent, at a time when his thoughts are described as being wrapped in dustsheets, like furniture in an unused room.

As far as large-mindedness goes, Vern is a non-starter. Its not easy to find the sparkle in a life devoted to acquisitiveness and double-dealing, to amoral manoeuvres that are shrewd but not shrewd enough. Spufford gives Vern a perverse streak of sensitivity in one supremely aestheticised area. He has a responsiveness to opera that makes it hard, when he spots Maria Callas in a restaurant, to concentrate on tricking a footballer into accepting liability for any debts his latest enterprise runs up. Out of the chrysalis of the usual him has crept this damp-winged other Vern, who only wants to stare even if the footballer, following Verns eyes, can see only a skinny, foreign-looking woman in her forties.

This aspect of Verns character is introduced early enough to substantiate later scenes, when for instance he stages a lavish banquet for himself on the lawn at Glyndebourne, the waiter cooking an omelette aux fines herbes over a silver spirit lamp, its blue flame almost invisible in the June sunlight, the aroma of chervil and butter advertising the success of the outer Vern, while the inner one waits for the rapture of curtain up. At other times he is called on to channel abstract thought, a cool examination of his own instinctive recoil from the old houses he specialises in renovating and selling on:

Chewed up by time, used up by time, in a funny way contaminated by time, as if all the lives lived in this heavy rookery for humans, first the posh ones with the wigs and ball dresses, then all the ever poorer clerks and labourers and flotsam from around the world, with their coughing children, and their meals cooked on gas rings in dirty corners, have made it impossible for there ever to be a fresh start here, a new beginning, there being so much living and dying already ingrained here, stuck to surfaces like grease, laid down in scungy thicknesses.

He even contemplates the idea that these buildings will still be standing when we are removed as mortal rubbish. The sense that Vern is a pint pot having a quart of insight poured into it is inseparable from the way this unspectacularly ambitious book works as a whole, as it seeks not only to track five individuals across two-thirds of a century but to sketch their city on a grander time scale. At one point, driving past Eltham on the A20, listening to Joan Sutherland in Lucia di Lammermoor on his cars sound system, what Vern sees comes close to a rival aria:

The 1930s semis with their triangular raised eyebrows; the Edwardian schools and the brutalist ones; the corner shops now selling lentils and fenugreek; the railway arches filled with little garages; everywhere the plane trees, the sycamores, the horse chestnuts, so wet now they stand like pulpy chandeliers, dribbling and drooling, filtering the light away so the pavements are dim beneath.

Some writers who started their careers with non-fiction are drawn to the freedom the novel offers, and this must in some way be true of Spufford, but the spirit of scrupulousness in his research carries over, deepening invention rather than confining it. Readers of his first novel, Golden Hill, could almost believe they understood the intricacies of 18th-century American monetary practice, unless called on to explain it themselves. He has admitted to a tiny slip in that book, the mention of liquorice as a confection rather than a medicinal root before the apothecary George Dunhill had the idea of adding sugar to it. A chance encounter on my part with an episode of the Antiques Roadshow suggests that a characters having trouble sleeping thanks to a loose spring is also (undamagingly) anachronistic for 1745.

Readers of Light Perpetual can get precise and unfussy answers to any number of questions. Who is responsible for Mikes version of power dressing? Val, the friend of British nationalists, of course.

There arent enough members of the white races vanguard for the uniforms to come from a factory. They have to be home-made. The blue BM crossed-circle came as a machine-embroidered patch, but she was the one who had to get it to work on a khaki shirt, who had to make the jacket and the armband, to improvise the Sam Browne belt He got photographed in it for his membership card, and now it hangs in the wardrobe in a dry-cleaning bag.

What makes of car would be driven by the first, semi-bohemian wave of gentrifiers in South-East London? Elderly green Saab, mossy Audi, silver Volvo estate missing a hubcap. What is the music like on the Assemblies of Salvation circuit of evangelical churches? Gospel settings of old hymns, and a touch of Highlife for those nostalgic for Ibadan, and new worship songs from the sacred (but still funky) end of soul. What sources of funding could an enterprising head teacher hope to tap in the first decade of this millennium? SEAL money, EiC money, EMAG money, LIG money, NDC money, NRF money. Nowhere does the virtue of compression become the vice of density or cross the line into knottiness of texture.

The paths of characters who were close as children hardly cross in later life. As a result, the single episode in which a main character intervenes in the life of another has an almost allegorical quality, something Spufford is unlikely to want if he did, he would have indulged the trope more freely. Alecs father was in the print, and Alec follows him into the business. In one lovely, lucid pageSpuffordhymns the compositors trade. Alec joyfully immerses himself in the physicality of work, held in a womb of mechanical noise, to be monitored with some spare fraction of a busy mind, because a variation or blockage in it could be a sign that Mama Linotype is about to squirt molten metal at your legs. By 1979, Alec is on strike. It turns out that he has committed his life to an obsolete technology. Now he must acquire some domestic skills while his wife, Sandra, goes out to work. Theres a knock on the door, and he recognises Vern, who is also at a low ebb, in search of any council tenant ill, old or lonely who can be persuaded to sell. With discounts available for council house buyers, at last theres a government thats on his side the same government that is busy crushing unions like Alecs. A chance remark of Alecs alerts Vern to the gentrifying trend on Bexford Rise. This is news to Vern, but hes not the type to waste time. The reader is offered a tableau: Opportunism superseding Principle.

The outward-facing aspect of the novel extends to the way its characters pay attention to people outside their own social groups. I remember Angela Carter saying that she warmed to any novel (I think she mentioned Maureen Duffys Capital) whose characters used public transport it made a nice change. Late in life, Alec makes vivid mental notes on his fellow passengers while travelling on the tube (Square-faced pasty white boy, with swags of beard at the corners of his jaw, like a playing-card kings). At the same age Jo, riding a 54 bus, observes white girls whose thongs show above the back of their low-rise jeans (God, what a stupid fashion) and black boys with heads shaved into cryptic sigils, getting on and off in obedience to the invisible frontiers of their postcode wars. Her favourite place on a bus has always been at the front of the top deck, enjoying that stilt-walkers sway, that giraffe-riders ungainly perch above the street. Alec imagines the future London he wont live to see, its green porcelain architecture borrowed from H.G. Wellss Time Machine a book he has never forgotten. Or the towers a kilometre high from which it will be possible to see the Channel gleaming in the sun. Or the shrunken half-drowned settlement ringed by steaming paddies. In the section describing Jos bus ride, Spufford inserts a complementary vision of the citys distant past: Bexford, Lewisham, Woolwich: permanent-sounding names for gravel beds left behind by the rivers random swinging this way and that across a basin of clay between hills, for millions of years during which there were no names, no city, no humans. Here is a speculation that cant easily be given to one of the novels characters, and so it appears as a paragraph within brackets, extraterritorial.

The initial set-up of Light Perpetual, with five figures, three male and two female, silhouetted against catastrophe, suggests an inverted version of The Bridge of San Luis Rey, Thornton Wilders critical and popular triumph of 1927. Wilder also began and ended his novel with the death of a group: five characters fall into a ravine when a fictional bridge in Peru collapses on 20 July 1714. This dramatic beginning allows Wilder to investigate the event under the symmetrical chapter headings of Perhaps an Accident and Perhaps an Intention. The early announcement of serious intention licenses him to explore playful and comic tones without fear of seeming trivial. Like the lead weights sewn into curtain hems, it makes sure the material hangs properly.

The framing device in Light Perpetual doesnt have so much to offer. Its a strange commemoration of the children who died in the New Cross Woolworths that unwrites the original disaster. The conceit of those non-deaths, announced and immediately annulled, seems to be a way of symbolically starting from zero, wiping the board clean. The novel could have followed any group of children over the same period and had as much to say about the sights, smells, sounds and social economy of a city in flux. It isnt a necessary or even an efficient way of enabling the reader to enter the narrative.

The book is structured in separate chronological sections, starting in 1949 and proceeding in leaps of fifteen years. They are announced by headings that use t to represent the time of the explosion (t + 5, t + 20 and so on), but the time scheme is arbitrary. A choice has been made to excise vast tracts of time so that what remains can be modelled with superlative fullness. Each of Updikes Rabbit novels concentrated on a single period, and Richard Ford did something similar in the sequence that began with The Sportswriter, meaning that no event need be skipped. Alec, dancing with his ex-wife, may feel that fifteen years are nothing, but fifteen years in these pages is long enough to contain a long prison sentence, subsequent rehabilitation and eventually the training required to answer phones as a Samaritan. Its long enough for a mod to become a skinhead, for a teaching career to begin and end. Its long enough for a black woman seen by her family as a QC in the making to become an MP in reality. For one of the characters, dying in a hospice, able to control the dosage of his morphine pump, time blurs and moves in jumps. People come and are suddenly gone, he blinks and night has become day or day become night. We wake to a changed world without any memory of having left it. Vicky is seriously ill with bulimia? We had no idea. Her grandfather Alec is shocked too, not having seen her for a while, but readers havent encountered Vicky since she was a toddler. When Jo refers to a toe-stubbing trip over times doorstep she is talking about a technical problem in synchronising a recording, but the phrase could be taken as a description of how the novel itself unfolds. A gap of fifteen years between sections seems to set the mesh of the net too wide.

In Seven Up!, Michael Apted chose a group of seven-year-olds and returned to his interview subjects at intervals of seven years. In 20 Sites n Years, a different sort of documentary project, Tom Phillips set out in 1973 to take pictures of twenty London streets on (roughly) the same day every year, at the same time of day and from the same position. There is only incidental human presence in the images, and at first the succession of years gives an impression of changelessness, but then there are sudden leaps, and even in the absence of drastic transformation there are nuances to be extracted, as Phillips describes: Although a quiet side street (or perhaps because of that) it seems to get dug up more frequently than any other: changes in the post-operative tar show where the latest incision has been made.

The human eye allows us to see a succession of still images projected at the appropriate speed as moving pictures. Readers of fiction have much more flexibility to generate an illusion of continuity, but at a certain point it breaks down. In his most recent novels, The Strangers Child and The Sparsholt Affair, Alan Hollinghurst introduced long gaps into the narrative in a way that requires the readers relationship with the story to be renegotiated almost from scratch (the new time period tends to bring with it new points of view, further testing the relationship). The obvious choice of fictional genre to combine coherence and a long, interrupted timespan is that undemanding form the family saga, and although it would be slightly mad to urge such a thing on writers as sophisticated and accomplished as Hollinghurst and Spufford, their solutions pose problems of their own. In Proust and Anthony Powell, the shock of character as it develops over time is situated within an immense continuity. Even so there can be a limit to what is plausible. Not every reader is convinced by the last incarnation of Powells Widmerpool, or by the transformation of Prousts Bloch or Gilberte. They would be still less persuasive if they werent part of an apparently seamless whole.

If time isnt continuous, it becomes barely recognisable. In Robert Coovers great story Going for a Beer, barely a thousand words long, the continuousness is deceptive, belonging to language and not to the experience language claims to represent. He finds himself sitting in the neighbourhood bar drinking a beer, it starts,

at about the same time that he began to think about going there for one. In fact, he has finished it. Perhaps hell have a second one, he thinks, as he downs it and asks for a third. There is a young woman sitting not far from him who is not exactly good-looking but good-looking enough, and probably good in bed, as indeed she is. Did he finish his beer? Cant remember. What really matters is: Did he enjoy his orgasm? Or even have one?

The reading brain smooths out the first slip forward in time, but they just keep coming until they cant be ignored. The effect is both rich and desolating, whether you read the story as a realistic account of the damage done to memory through alcohol, or as a wild exaggeration of inhabiting the consequences of decisions you dont quite remember making. Spufford refers to something similar in Light Perpetual when Alec, attending a family wedding, thinks of marriage as an exceptional event on precisely this basis, the astonishment of standing on the magic pivot, the trampoline of transformation, where your life is being changed and for once you know it.

In the weakest part of the novel, Ben is in his late thirties and working as a bus conductor. He is prey to obsessive thoughts (specifically, images of cannibalistic barbecue) that leave him barely able to function. Images of dripping fat and bubbling skin fill his mind, and the page fills up with the words charred ribs, first in italics and then full caps. This is new: in the 1964 episode Ben was a voluntary patient in a mental hospital, dosed up on Largactil and grateful for it, escaping awareness of an unnamed Trouble. In 1979 his misery can be blurred in the evening by dope, but must be endured during the day, and the episode ends with a one-phrase paragraph: So many days like this.

Its precisely this dailiness thats been removed from Light Perpetual, and fifteen yearliness cant take its place. Apteds seven-year gaps meant the series couldnt offer dailiness, but it did give a sense of how intractable, how chronic, things like class position and mental illness could be. When Ben next appears, in 1994, his demons have been exorcised. He is a new man, redeemed by love and faith; although his transformation is tenderly described, it seems unreal. The conjurors wand that abolishes fifteen years at a go cant also restore the magic continuity of time.

The rest is here:

Adam Mars-Jones He blinks and night is day: 'Light Perpetual' LRB 17 June 2021 - London Review of Books

When Mars Hill Church was planted in Seattle in 1996, few would have imagined where it would lead. But in the next 18 years, it would become one of the largest, fastest-growing, and most influential churches in the United States. Controversy plagued the church, though, due in no small part to the lightning-rod personality at its helm: Mark Driscoll.

By 2014, the church had grown to 15,000 people in 15 locations. But before the year was over, the church collapsed. On January 1, 2015, Mars Hill was gone.

Hosted by Mike Cosper, The Rise and Fall of Mars Hill explores the inside story of this church, its charismatic leader, and the conflicts and troubles that brought about its end. Youll hear from insiders and experts, tracing the threads of this story to so many others that shape the church today.

Listen to the trailer and subscribe today. The full series launches on June 22.

See original here:

Full-Length Trailer: The Rise and Fall of Mars Hill - ChristianityToday.com

NASA's Mars Perseverance rover is on the cusp of landing on the Red Planet after a seven-month journey. Here's what happens next. USA TODAY

On the surface, Mars presents itself as a world on the verge of inhospitality.

Average temperatures that hover around negative 81 degrees. A thin, carbon dioxide-rich atmosphere sometimes rendered opaque by planet-wide dust storms that can even be seen from Earth. Gravity thats just one-third of what humans have evolved to tolerate.

But the Red Planets features tell a different story.

Looking at photos captured by satellites in orbit, it doesnt take much imagining to see Mars was likely once home to rivers of running water and enormous crater-lakes. With the right conditions, perhaps this planet that gets its rusty color from iron oxide-rich rocks could once have been suitable for life or at least life as we know it.

This dichotomy has left experts asking one of the most difficult-to-answer questions in science today: What happened to Mars, and can the same thing happen here on Earth?

We know that Mars had a bad past, said Thomas Zurbuchen, associate administrator of NASAs Science Mission Directorate. We used our Spirit and Opportunity rovers (2003) to follow the water in search of answers as to why this once ocean world is now dry and desolate. Following those missions came our Curiosity rover, which landed on Mars in 2012 and is still operating.

Augmented reality:Mission to Mars: Explore the Perseverance rover

Now its time for NASAs next robotic explorer Perseverance to follow in the dusty tracks of its predecessors. After a 293-million-mile trek across the expanse since its July 2020 launch from Cape Canaveral Space Force Station, the upgraded rover is slated to land on the Red Planet at 3:55 p.m. EST Thursday.

Its target: Jezero Crater, a harsh surface feature that was likely once a deep lake fed by rivers of running water.

Perseverance is our robotic astrobiologist, and it will be the first rover NASA has sent to Mars with the explicit goal of searching for signs of ancient life, Zurbuchen said.

But before it can begin roving its targeted landing site at a breakneck 0.1 mph, Perseverance has to pull off a series of risky landing maneuvers all by itself.

In this animation, NASA's Perseverance rover is seen during its "Seven Minutes of Terror," or the entry, descent, and landing process. Using a unique "Sky Crane Maneuver," the 10-foot rover will land on Mars on Feb. 18, 2021. Florida Today

Getting to Mars with help from a United Launch Alliance Atlas V rocket and interplanetary cruise stage was one thing, but slowing down from thousands of miles an hour to a soft 1.7 mph at landing is another.

This seven-minute process from 3:48 p.m. to 3:55 p.m. is known as the seven minutes of terror. Because signals take 11 minutes to reach Earth, human input in the event of a mishap is impossible. Perseverance is on her own.

The nail-biting entry is made even more tense by the fact that once mission managers at NASAs Jet Propulsion Laboratory in California get the first confirmation of entry, Perseverance will have already landed or crashed in real-time. The unavoidable signal delay, however, is a short hurdle for teams that have been waiting for this moment for a decade.

Landing on Mars is really all about finding a way to stop and land in a safe place, said Al Chen, NASA's entry, descent, and landing lead at the Jet Propulsion Laboratory.

As it approaches Mars thin atmosphere, the heat shield affixed to the front of Perseverance's protective capsule will bear the brunt of fiery entry while also acting as an airbrake of sorts. A massive 70-foot parachute then automatically deploys, further slowing down the 2,200-pound rover.

While coming down on the parachute, Perseverance needs to figure out where it is, Chen said. Itll jettison the heat shield that protected us during entry, and it will use a radar and a new system we call Terrain-Relative Navigation to figure out where it is.

After the newly exposed radar and cameras have a lock on Perseverances location and landing prospects, its time for the riskiest part: dropping out of the protective capsule with a web of machinery and eight retrorockets, which begin firing to slow the rover down.

About 65 feet from the surface, the still-firing retrorockets slow Perseverances approach to 1.7 mph. The descent stage then kicks off the Sky Crane Maneuver, which uses strong nylon cords to slowly lower the rover to the ground. After confirmation of touchdown, the sky crane severs the cords and flies off to put distance between it and the rover.

Perseverance is expected to begin transmitting photos of its new surroundings immediately after landing.

NASA's Perseverance rover is seen on Mars in this rendering by the agency. The 10-foot robotic vehicle will touch down on the surface on Feb. 18, 2021, after a series of complicated maneuvers.(Photo: NASA)

NASAs 10-foot-long, $2.4 billion Perseverance roveris equipped with suites of technologies designed to aid in the hunt for life.

Sixteen engineering and science cameras support safe navigation and help observe the surface, from extreme close-ups to far away. Some of these are part of larger scientific systems, like an ultraviolet spectrometer and another that uses X-rays.

A 7-foot arm attached to the front of Perseverance includes a powerful drill that can pull core samples from rocks that interest scientists. The samples can then be sealed and stored in tubes inside the rovers main body for more analysis later.

Perseverance also has the capability to remove the stored samples and leave them in designated spots around Jezero Crater. A future mission yet to be scheduled could one day land on the Red Planet, pick up the tubes and then fly off to return them to scientists on Earth.

Unlike older Mars rovers, Perseverance and its Curiosity sibling rely on nuclear power. Essentially a nuclear battery, both rovers use energy generated by the decay of plutonium to charge onboard lithium batteries during dormancy. While the Department of Energy-provided hardware can power Perseverance for up to 14 years, the rovers mission is currently set to last at least one Martian year (two Earth years).

Perseverance even has a friend hitching a ride for this mission: Ingenuity. This 4-pound drone will host the first-ever flight on another planet during a roughly monthlong window. Though Ingenuityhas no science hardware, two cameras will help steer the drone and teach NASA engineers how to fly on a world with an atmosphere just 1% as dense as Earths.

But why look for life past or present in the first place? For Manasvi Lingam, a professor of astrobiology, aerospace, physicsand space sciences at Florida Tech, its the ultimate journey.

Any sign of life will of course be one of the most momentous discoveries in the entire history of humanity, Lingam said. Even if it is extinct life, just knowing that there was something out there is certainly Nobel Prize-level.

Lingam acknowledges that getting even a hint of an answer usually leads to more questions.

Would finding life on Mars inform our perception of how common it is elsewhere in the universe? If life on Mars and Earth appear to be similar, could the millennia-old theory of panspermia that life can spread via asteroids or comets, for example see a resurgence? Or what if the discovery is so foreign that it doesnt appear to rely on the building blocks of life were used to, like DNA and RNA?

All of these questions are really fascinating, Lingam said. If you find something very alien, thats great and we can try to understand what it is.

It might even have some practical implications because humans learn from biology all the time. Thats in fact how weve made a lot of drugs we looked at actual organisms and borrowed ideas from them, he said.

Autoplay

Show Thumbnails

Show Captions

No follow-up rovers are solidly planned after Perseverance. Nicknamed Percy by her JPL mission managers, shes on her own in Jezero Crater for the foreseeable future.

But what about dropping sample tubes for pickup by a separate mission? Thats still in the works at NASA.

Lingam said a sample return mission has two advantages for scientists: the breadth and number of instruments available on Earth vastly outclass whats available on Perseverance; and despite technological advances, having a human eye looking at samples is still the preferred method.

For his research, Lingam would like to see more missions to Venus a planet that hasnt seen enough investigation surrounding potential for life, he said. Missions like Perseverance, combined with upcoming investigations of other parts of our solar system, will ultimately provide a more holistic view of the history of life.

Theres definitely part of me that wants to believe theres life in the oceans of Europa, that there was life on Mars, and potentially even in the clouds of Venus, Lingam said. Its always more tempting to think of a cosmos that is filled with all kinds of weird and wonderful life, because that would mean were not alone.

One should not allow the belief to cloud ones mind about the data and the scientific method. But I do hope that there is life out there.

Contact Emre Kellyon Twitterat @EmreKelly.

By the numbers: NASA's Perseverance rover

---

Timeline: Seven minutes of terror (all times Eastern on Feb. 18)

Visitfloridatoday.com/spaceat 3 p.m. Thursday to watch live as Perseverance targets a landing on the Red Planet.

Read or Share this story: https://www.usatoday.com/story/news/nation/2021/02/15/nasa-mars-mission-2021-perseverance-rover-set-landing-date/4484978001/

See the original post here:

NASA Mars mission 2021: Perseverance rover landing date, time

The first image of Mars snapped by the Al Amal, or Hope, spacecraft. The photo was captured at a distance of 15,500 miles from the planet's surface.

Mars is the place to be this month. Two spacecraft have already entered orbit around the red planet: China's Tianwen-1 got there on Feb. 10. And a day earlier, the United Arab Emirates made history bysliding the Al Amal (Hope) spacecraft into Martian orbitand becoming just the fifth country to reach Earth's dusty, barren neighbor.

Thefirst-ever Arab interplanetary mission has snapped a couple of images of Mars during its journey so far, but nothing quite like what it delivered early Sunday. From a distance of about 15,500 miles (25,000 kilometers), the probe's camera -- officially known as the Emirates eXploration Imager (EXI) -- captured a picturesque view of Mars as a yellowed semicircle against the black curtain of space.

Some of Mars most famous features are visible in the image. Olympus Mons, the biggest volcano in the solar system peeks out at the terminator, where the sunlight wanes, while the three volcanoes of the Tharsis Montes dazzle under a mostly dust-free sky.

Olympus Mons is barely visible at the terminator, where night meets day. It's circled here, in red.

From the cosmos to your inbox. Get the latest space stories from CNET every week.

The picture was shared in a tweet by Sheikh Mohamed bin Zayed Al Nahyan, de facto ruler of the UAE.

"The transmission of the Hope Probe's first image of Mars is a defining moment in our history and marks the UAE joining advanced nations involved in space exploration," he tweeted Sunday.

The Al Amal mission hopes to provide the most complete picture of the Martian atmosphere yet. It's suite of instruments includes the EXI camera and both an ultraviolet and infrared spectrometer. Detailed observations will allow researchers to determine how particles escape from the gravity of Mars and reveal the mechanisms of global circulation in the lower atmosphere.

You can find previous images from the Hope probe at theEmirates Mars Mission website.

FollowCNET's 2021 Space Calendarto stay up to date with all the latest space news this year. You can even add it to your Google Calendar.

Read more:

The first photo of Mars delivered by the UAE's Hope probe ...

Science Operations

Of course, communications dont stop after landing. Thats when the complicated task of sending commands to Perseverance and receiving the rovers huge science data output will begin.

During its mission, the rover will have all of the orbiters in the Mars Relay Network for support including NASAs MRO, MAVEN, Odyssey, and ESAs TGO, which has been playing a key role in the network for the past few years. Even ESAs Mars Express orbiter will be available for emergency communications should the need arise. While the NASA orbiters communicate exclusively with the DSN, the ESA orbiters also communicate via the European Space Tracking network and ground stations located in Russia.

Although the Mars Relay Network has expanded to include more spacecraft and more international partners, with every new surface mission comes added complexity when scheduling the relay sessions for each orbiter flyover.

Curiosity and InSight are near enough to each other on Mars that they are almost always visible by the orbiters at the same time when they fly over. Perseverance will land far enough away that it cant simultaneously be seen by MRO, TGO, and Odyssey, but sometimes MAVEN, which has a larger orbit, will be able to see all three vehicles at the same time, added Gladden. Since we use the same set of frequencies when communicating with all three of them, we have to carefully schedule when each orbiter talks to each lander. Weve gotten good at this over the last 18 years as rovers and landers have come and gone, including collaborating with ESA, and were excited to see the Mars Relay Network set new throughput records as it returns Perseverances huge data sets.

Ultimately, this communications endeavor connecting Earth and Mars will enable us to see high-resolution images (and hear the first sounds) captured by Perseverance, and scientists will be able to further our knowledge about the Red Planets ancient geology and fascinating astrobiological potential.

More About Perseverance

A key objective of Perseverances mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planets geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith.

Subsequent missions, currently under consideration by NASA in cooperation with ESA, would send spacecraft to Mars to collect these sealed samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 mission is part of a larger NASA initiative that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. Charged with returning astronauts to the Moon by 2024, NASA will establish a sustained human presence on and around the Moon by 2028 through NASAs Artemis lunar exploration plans.

JPL, which is managed for NASA by Caltech in Pasadena, California, built and manages operations of the Perseverance rover.

For more about Perseverance:

mars.nasa.gov/mars2020/

nasa.gov/perseverance

For more information about NASA's Mars missions:

https://www.nasa.gov/mars

More About DSN

The Deep Space Network is managed by JPL for NASAs Space Communications and Navigation (SCaN), which is located at NASAs headquarters within the Human Exploration and Operations Mission Directorate.

More About the Mars Relay Network

The Mars Relay Network is part of the Mars Exploration Program, which is managed at JPL on behalf of NASAs Planetary Science Division within its Science Mission Directorate.

Read more:

News . The Mars Relay Network Connects Us to NASA's Martian Explorers - Jet Propulsion Laboratory

Mars is the fourth planet from the Sun and is the second smallest planet in the solar system. Named after the Roman god of war, Mars is also often described as the Red Planet due to its reddish appearance. Mars is a terrestrial planet with a thin atmosphere composed primarily of carbon dioxide.

Mars has two small moons, Phobos and Deimos. They were discovered in 1877 by astronomer Asaph Hall, who named them for the Latin terms fear and panic. These moons are thought to be captured asteroids and are among the smallest natural satellites in the solar system.

Mars has the largest volcano in the solar system Olympus Mons. It measures some 600 kilometres across and rises nearly 27 kilometres above the surrounding terrain. It is a shield volcano built by the continuous action of flowing lava over millions and millions of years that began some 3 billion years ago.

Olympus Mons is part of a complex of volcanoes that lie along a volcanic plateau called the Tharsis Bulge. This entire region lies over a hotspot, a place in the planets crust that allows magma from deep inside to flow out to the surface.

The Valles Marineris is an extensive canyon system on the Mars equator. It is 4,200 kilometres long and, in places, is 7 kilometres deep. On Earth, it would span the entire North American continent and beyond.

Mars has has a very primitive form of plate tectonics, and the action of two plates past each other began splitting the surface some 3.5 billion years ago. That set the stage for the formation of the Valles Marineris.

Sources: https://solarsystem.nasa.gov/planets/mars/overview/ , https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html, https://astrogeology.usgs.gov/maps/mars-viking-hemisphere-point-perspectives First Published: June 2012Last Updated: May 2020Author: Chris Jones

More:

Mars Facts - Interesting Facts about Planet Mars

It's a busy February for Mars, with three probes from three separate countries arriving at the Red Planet over the course of just nine days. But this Martian party didn't happen by coincidence it has to do with the mechanics of both Earth and Mars orbits.

The United Arab Emirates' first interplanetary mission, the Hope probe, achieved Mars orbit Tuesday (Feb. 9), as Live Science sister site Space.com reported. China's first interplanetary mission, Tianwen-1, is scheduled to enter its own Martian orbit Wednesday (Feb. 10). The Chinese probe includes both an orbiter and a lander with a rover onboard, which is expected to try to land on the surface in May. And on Feb. 18, NASA's first-of-its-kind descent vehicle will reach Mars and plunge directly through its atmosphere. If all goes according to plan, the vehicle will shed its outer shell and use rockets to stop its descent at the last moment. Then it will hover above the surface to lower the rhinoceros-sized, nuclear-powered, $2.7 billion Perseverance rover to the dirt via skycrane.

Book of Mars: $22.99 at Magazines Direct

Within 148 pages, explore the mysteries of Mars. With the latest generation of rovers, landers and orbiters heading to the Red Planet, we're discovering even more of this world's secrets than ever before. Find out about its landscape and formation, discover the truth about water on Mars and the search for life, and explore the possibility that the fourth rock from the sun may one day be our next home.View Deal

All these robots showing up at almost the exact same time is no coincidence, said Jonathan McDowell, a Harvard University astrophysicist and spaceflight expert.

Mars and Earth are like "runners on a circular racetrack," he said. "And the really fast runner [Earth] regularly laps the runner just on the outside [Mars]. So sometimes they're right next to each other, and sometimes they're on opposite sides of the track." This Earth-Mars cycle, meaning Earth completely laps Mars, takes about two years to complete.

It would take an enormous rocket, tons of fuel and much more time to reach Mars from Earth while the planets are far away from each other, McDowell told Live Science. But launching while the planets are at their absolute closest when they are 38.6 million miles (62.1 million kilometers) apart on average isnt the most efficient way to get to Mars either.

There's an earlier point in the planets' two-year cycle where the journey takes less time and requires less fuel. At that point, which occurs once during the two-year cycle, Earth is a bit behind Mars but continues to move faster than its neighbor. This positioning allows the spacecraft to enter a so-called "Hohmann transfer orbit," named after German engineer Walter Hohmann, who worked out the underlying mathematics in 1925.

Related: 5 Mars myths and misconceptions

Here's how that works:

No rocket carries enough fuel to burn all the way between Earth and Mars, a distance that ranges between tens and hundreds of millions of miles.

That means any interplanetary adventure begins with a brief, intense period of acceleration, followed by a long stretch of coasting. The job of the rocket engines during that initial period of acceleration is to put the spacecraft into an orbit around the sun that will intersect with Mars as soon as possible. The most efficient path between the planets is therefore the solar orbit intersecting with Mars that can be reached with the least expenditure of fuel, and that orbit becomes available once every two years.

But space agencies don't have to nail that day exactly. As long as they launch during a window of a couple weeks around the date,they can place their spacecraft on Hohmann transfer orbits. Tarry longer than a couple weeks, however, and the trip starts getting much more difficult very quickly.

The Hope orbiter launched July 19, 2020, Tianwen-1 on July 23 and Perseverance on July 30. The gaps between the spacecrafts' arrivals don't exactly line up with their launch dates due to minor differences in their rocket technology, trajectories through space and destinations, McDowell said. (It takes a different angle of approach, for example, to plunge directly into the planet's atmosphere than it does to enter a high orbit as Hope has done.)

It's not the first time Martian orbital space has been this crowded, McDowell pointed out. The Soviet Union launched four spacecraft to Mars in 1973, though one failed to attain orbit and none of the other three worked as intended upon arrival. Two Soviet spacecraft and one American spacecraft launched to Mars in 1971, and all had at least partially successful missions. (Both nations planned additional probes that year, but the American Mariner 8 probe failed during launch and the Soviet Kosmos 419 never escaped low-Earth orbit.)

Related: Here's every spaceship that's ever carried an astronaut into orbit

What's different this year, McDowell said, is the sheer diversity of spacecraft reaching Mars, and the fact that several additional probes are already active around the planet. NASA has three orbiters active in Martian orbit, the European Space Agency (ESA) has one of its own and one orbiter that's a joint project with the Russian Roscosmos, and the Indian Space Research Organization has an active orbiter as well. NASA's Curiosity rover and InSight lander are also still active on the Martian surface.

Despite that relatively crowded situation, McDowell said he doubts any of the probes will even come within tens of thousands of miles of each other, even if none of the countries had checked their trajectories with each other in advance.

"Space is big," he said.

Originally published on Live Science.

More here:

Why Mars is having its busiest two weeks in 47 years - Livescience.com

BWX Technologies, Inc. | People Strong, Innovation Driven

Warning: Javascript must be enabled within your browser's settings for this site to function properly.

Your browser appears to be out of date, and is not supported by this site. For the best experience, we recommend that you upgrade to a more modern browser. You can find a list of modern browsers from http://www.browsehappy.com.

We use technical and analytics cookies data to ensure that we give you the best experience on our website. For more information visit our Privacy Page.

ACCEPT

of nuclear innovation

delivered for Naval NuclearPower

generators delivered to nuclear powerplants

high-consequence U.S. governement sitesmanaged

We are the only company in the U.S.executingproduction contracts for TRISO fuel.

2021 BWX Technologies. Inc. All Rights Reserved. PrivacyContact UsTerms of Use

The products and services described herein are provided by subsidiaries of BWX Technologies, Inc.

Link:

BWX Technologies, Inc. | People Strong, Innovation Driven

A new NASA paper provides the most detailed map to date of near-surface water ice on the Red Planet.

So you want to build a Mars base. Where to start? Like any human settlement, it would be best located near accessible water. Not only will water be crucial for life-support supplies, it will be used for everything from agriculture to producing the rocket propellant astronauts will need to return to Earth.

Schlepping all that water to Mars would be costly and risky. Thats why NASA has engaged scientists and engineers since 2015 to identify deposits of Martian water ice that could be within reach of astronauts on the planets surface. But, of course, water has huge scientific value, too: If present-day microbial life can be found on Mars, it would likely be nearby these water sources as well.

A new study appearing in Nature Astronomy includes a comprehensive map detailing where water ice is most and least likely to be found in the planets northern hemisphere. Combining 20 years of data from NASAs Mars Odyssey, Mars Reconnaissance Orbiter, and the now-inactive Mars Global Surveyor, the paper is the work of a project called Subsurface Water Ice Mapping, or SWIM. The SWIM effort is led by the Planetary Science Institute in Tucson, Arizona, and managed by NASAs Jet Propulsion Laboratory in Southern California.

The next frontier for Mars is for human explorers to get below the surface and look for signs of microbial life, said Richard Davis, who leads NASAs efforts to find Martian resources in preparation for sending humans to the Red Planet. We realize we need to make new maps of subsurface ice to improve our knowledge of where that ice is for both scientific discovery and having local resources astronauts can rely on.

In the near future, NASA plans to hold a workshop for multidisciplinary experts to assess potential human-landing sites on Mars based on this research and other science and engineering criteria. This mapping project could also inform surveys by future orbiters NASA hopes to send to the Red Planet.

NASA recently announced that, along with three international space agencies, the signing of a statement of intent to explore a possible International Mars Ice Mapper mission concept. The statement brings the agencies together to establish a joint concept team to assess mission potential as well as partnership opportunities between NASA, the Agenzia Spaziale Italiana (the Italian Space Agency), the Canadian Space Agency, and the Japan Aerospace Exploration Agency.

Location, Location, Location

Ask Mars scientists and engineers where the most accessible subsurface ice is, and most will point to the area below Mars polar region in the northern hemisphere. On Earth, this region is where you find Canada and Europe; on Mars, it includes the plains of Arcadia Planitia and glacier-filled valleys in Deuteronilus Mensae.

Such regions represent a literal middle ground between where to find the most water ice (the poles) and where to find the most sunlight and warmth (the equator). The northern midlatitudes also offer favorable elevations for landing. The lower the elevation, the more opportunity a spacecraft has to slow down using friction from the Martian atmosphere during its descent to the surface. Thats especially important for heavy human-class landers, since Mars atmosphere is just 1% as dense as Earths and thus provides less resistance for incoming spacecraft.

Ultimately, NASA tasked the SWIM project with figuring out how close to the equator you can go to find subsurface ice, said Sydney Do, the Mars Water Mapping Project lead at JPL. Imagine weve drawn a squiggly line across Mars representing that ice boundary. This data allows us to draw that line with a finer pen instead of a thick marker and to focus on parts of that line that are closest to the equator.

But knowing whether a surface is hiding ice isnt easy. None of the instrument datasets used in the study were designed to measure ice directly, said the Planetary Science Institutes Gareth Morgan, the SWIM-project co-lead and the papers lead author. Instead, each orbiter instrument detects different physical properties high concentrations of hydrogen, high radar-wave speed, and the rate at which temperature changes in a surface that can suggest the presence of ice.

Despite having 20 years of data and a fantastic range of instruments, its hard to combine these datasets, because theyre all so different, Morgan said. Thats why we assessed the consistency of an ice signal, showing areas where multiple datasets indicate ice is present. If all five datasets point to ice bingo.

If, say, only two of them did, the team would try to suss out how consistent the signals were and what other materials could be creating them. While the different datasets werent always a perfect fit, they often complemented one another. For example, current radars peer deep underground but dont see the top 30 to 50 feet (10 to 15 meters) below the surface; a neutron spectrometer aboard one orbiter measured hydrogen in the uppermost soil layer but not below. High-resolution photos revealed ice tossed onto the surface after recent meteorite impacts, providing direct evidence to complement radar and other remote-sensing indicators of water ice.

Next Steps

While Mars experts pore over these new maps of subsurface ice, NASA is already thinking about what the next steps would be. For one, blind spots in currently available data can be resolved by sending a new radar mission to Mars that could home in on the areas of greatest interest to human-mission planners: water ice in the top layers of the subsurface.

A future radar-focused mission targeting the near surface could also tell scientists more about the mix of materials found in the layer of rock, dust, and other material found on top of ice. Different materials will require specialized tools and approaches for digging, drilling, and accessing water-ice deposits, particularly in the extreme Martian environment.

Mapping efforts in the 2020s could help make human missions to Mars possible as early as the 2030s. But before that, therell be a robust debate about the location of humanitys first outpost on Mars: a place where astronauts will have the local water-ice resources needed to sustain them while also being able to make high-value discoveries about the evolution of rocky planets, habitability, and the potential for life on worlds beyond Earth.

News Media ContactsAndrew GoodJet Propulsion Laboratory, Pasadena, Calif.818-393-2433andrew.c.good@jpl.nasa.gov

Alana Johnson / Grey HautaluomaNASA Headquarters, Washington202-672-4780 / 202-358-0668alana.r.johnson@nasa.gov / grey.hautaluoma-1@nasa.gov

Continue reading here:

Where Should Future Astronauts Land on Mars? Follow the Water NASA's Mars Exploration Program - NASA Mars Exploration

Abstract

A major quest in Mars exploration has been the hunt for atmospheric gases, potentially unveiling ongoing activity of geophysical or biological origin. Here, we report the first detection of a halogen gas, HCl, which could, in theory, originate from contemporary volcanic degassing or chlorine released from gas-solid reactions. Our detections made at ~3.2 to 3.8 m with the Atmospheric Chemistry Suite and confirmed with Nadir and Occultation for Mars Discovery instruments onboard the ExoMars Trace Gas Orbiter, reveal widely distributed HCl in the 1- to 4-ppbv range, 20 times greater than previously reported upper limits. HCl increased during the 2018 global dust storm and declined soon after its end, pointing to the exchange between the dust and the atmosphere. Understanding the origin and variability of HCl shall constitute a major advance in our appraisal of martian geo- and photochemistry.

Chlorine is present in the atmospheres of Earth and Venus and plays a critical role in their photochemical cycles. In Earths troposphere, hydrogen chloride (HCl) is mainly sourced from sea salt aerosols, and its abundance partly controls the oxidizing potential of the atmosphere by interacting with ozone and hydroxyl radicals (OH) (1). In the stratosphere, relatively inert HCl is the main reservoir species, releasing chlorine radicals in heterogeneous processes that subsequently participate in ozone layer chemistry and seasonal polar ozone depletion. On Venus, HCl is also the dominant reservoir of chlorine, and its destruction via photolysis produces reactive chlorine species that are critical to the stability of its CO2 atmosphere (2). HCl has never been observed in the atmosphere of Mars but has been suggested and sought as an indicator of active magmatic processes (3). Stringent upper limits of 0.2 to 0.3 parts per billion volume (ppbv) were established (4, 5).

The primary science goal of the European Space Agency (ESA)Roscosmos ExoMars Trace Gas Orbiter (TGO) mission is to make highly sensitive measurements of trace atmospheric species, including volcanic gases (6). TGO carries two dedicated spectrometers, the Atmospheric Chemistry Suite (ACS) (7) and the Nadir and Occultation for Mars Discovery (NOMAD) suite (8). From the start of the mission in April 2018, the TGO instruments measured multiple known atmospheric gases and their isotopologues (915).

Here, we discuss the first positive detection of a previously undetected gas-phase molecule in the atmosphere of Mars by TGO, hydrogen chloride (HCl). Figure 1 shows a sequence of spectra that highlight the HCl absorption features detected by ACS. They were measured on 4 January 2019 at 73S latitude [heliocentric solar longitude (LS) = 318, late northern winter or southern summer on Mars]. As the instruments line of sight (LOS) moves deeper into the atmosphere during a solar occultation (SO) (7), we can retrieve the vertical profile of the HCl mixing ratio (see Materials and Methods). The spectra are zoomed on the spectral ranges around three distinct features in the R branch of the HCl 10 transition band. The depth of absorption due to HCl reaches 3 to 4%, while the signal-to-noise ratio per pixel of the instrument, although dependent on the dust content in the atmosphere, is generally over 3000 to 5000. Neighboring absorption lines in Fig. 1 are caused by water, semiheavy water (HDO), and the H37Cl isotopologue of HCl. In all, ACS detects 12 spectral features belonging to H35Cl and H37Cl in the P and R branches of its 1 fundamental rotational band.

Each panel shows spectra recorded as sequential tangent heights, indicating how the HCl features evolve with altitude. The occultation shown was recorded on LS = 318 at a latitude 73.5.

Figure S1 shows the wider spectral range covered by ACS and the contributions of different gases, and fig. S2 shows fits for HCl lines not shown in Fig. 1. The detection of HCl by ACS is corroborated by NOMAD measurements. HCl can be detected using several diffraction orders covering the 2600 to 3100 cm1 spectral range (see fig. S3). The vertical profiles of the HCl mixing ratio are presented in Fig. 2. We observe three families of altitude profiles. In the Northern Hemisphere, mixing ratios of 1 to 2 ppbv are observed mostly at altitudes in the range of 15 to 25 km, decreasing toward the surface (Fig. 2A). In the Southern Hemisphere, a series of observations were made prior to LS = 300, during which time we were unable to probe below 15 km, but observed 2 to 3 ppbv between 20 and 30 km (Fig. 2B). After LS = 300, we observed higher abundances, but HCl was entirely constrained below 15 km (Fig. 2C). The differences between Fig. 2 (B and C) reflect changes in the physical state of the atmosphere as the dust storm declines, which are also tracked by water vapor and aerosols. During this time, dust settled to the surface and lower atmosphere, followed by cooling and contraction, and a lowering of the hygropause.

Profiles are grouped as (A) Northern Hemisphere observations between LS = 210 and 330, (B) Southern Hemisphere observations between LS = 245 to 290, and (C) Southern Hemisphere observation between LS = 310 and 325. Retrievals on a 1-km grid are shown as solid lines, and retrievals at the tangent heights are shown at points with uncertainties derived from the retrievals matrix of partial derivatives. The mean of the ensemble is shown in purple with a shaded area showing the SD. The ensemble of retrievals is shown in fig. S4.

A latitudinal map of all HCl detections and upper limits is shown in Fig. 3A as a function of time, from LS = 163 in Mars Year 34 (MY34) (April 2018) to LS = 166 in MY35 (March 2020). For observations where HCl is not observed, a lower limit is given (see fig. S5), which is generally <0.2 ppbv and often ~0.1 ppbv. No firm detection was made between the beginning of the TGO science phase until the global dust storm (GDS) period. A few values have been retrieved with a 1-sigma confidence level, but they have the same magnitude (<1 ppbv) as the upper limits established in nearby occultations and those previously set by ground-based observations of 0.3 to 0.6 ppbv (4, 5). HCl is detected starting from LS = 230 and persists until around LS = 350. There are over 140 positive detections made by ACS and nearly 50 by NOMAD over the same time period.

All ACS MIR occultations are shown in gray, and those with the spectral range used for HCl, but not bearing strong HCl signatures, are shown as triangles, with the color indicating a lower limit of the HCl VMR. Observations with detected HCl lines are indicated with circles and colored by their maximum retrieved HCl mixing ratio at between 10 and 30 km. Additional retrievals using NOMAD SO are shown with diamonds. Science operations began on LS = 163 in MY34 and continued through LS = 166 in MY35 at the time of writing. The GDS commenced around 190 and was followed by a second storm around LS = 320, and the mean dust opacity (16) is shown in (A). (B) The corresponding lowest usable tangent height for ACS observations, limited by transmission levels below this point being only a few percent.

This time period, coinciding with seasonally enhanced dust, was punctuated by the onset of a GDS, beginning in the Southern Hemisphere around LS = 190, followed by a second, regional, storm at around LS = 320, with dust persisting through LS = 190 to 350 (16). The dust, lofted to heights of 30 to 50 km, is radiatively active and causes the atmosphere to heat and expand while intensifying Hadley cell circulation. Water vapor normally restricted to near the surface is elevated to create a hygropause near 80 km with mixing ratios around 150 ppmv, as observed by TGO (11, 12) and reproduced by modeling (17). Dust affects SO observations in such a way that the dust storm imposed limits on the lowest observable altitude of TGO instruments. Figure 3B shows the corresponding minimum altitude in the atmosphere that we can observe due to aerosol loading (see also fig. S6). Still, even during the peak of the GDS, polar latitudes remained relatively free from aerosols. During this period, we begin to see HCl frequently in the Northern and Southern Hemispheres, suggesting HCl was already present and spread by atmospheric circulation. During the decline of the storm (from LS ~ 240) and through the whole perihelion season, the map shows the densest, quasi-complete presence of HCl in both hemispheres, including a few detections at mid-latitudes, where observation conditions are not optimal. After the second regional dust storm of MY34, the detections become less frequent, and during MY35, we only occasionally see low levels of HCl in our spectra. At LS = 75, the HCl upper limit of ~0.1 ppbv that we derive from ACS is consistent with the upper limit of 0.3 ppbv (3-sigma) previously determined at the same season from the Herschel satellite (4).

The observations just described suggest that the source of HCl is aerosol chemistry occurring with the dust particles lofted into the atmosphere. However, this is not the only possible source of HCl, and the distributions observed by TGO may result from several possible interactions that may be interrelated. We must also emphasize that the geometry of the SO technique does not always allow us to observe the lowest few kilometers of the atmosphere that may also contain HCl, while previous searches for HCl observed the full atmospheric column and were sensitive to these layers.

An alternative explanation for the presence of HCl in the martian atmosphere is as a result of recent surface volcanism or subsurface magmatic activity. HCl is a minor gas emitted by terrestrial volcanism, and past martian volcanism has been suggested to be the source of contemporary surface chloride minerals (18). However, we note that outgassing of HCl related to magmatism (whether directly at the surface or at depth) should be accompanied by seismic activity and a suite of other sulfur-bearing and carbon-bearing molecules. Such molecules, SO2 in particular, have not been detected on Mars so far (19), and no correlation of HCl observations with Marsquakes measured by the InSight lander is apparent [noting that InSight measurements began at the end of February 2019 (LS = 340) and that seismicity on Mars is lower than projected (20)]. In addition, the fact that the HCl increase is detected almost simultaneously at very distant locations of both hemispheres is difficult to reconcile with local release at the surface.

In the terrestrial troposphere, the majority of the HCl is not volcanic but produced from reactions between acids and hydrated NaCl originating from sea-salt aerosols (21). While there are no marine aerosols currently produced on Mars, there is a notable coincidence between HCl detections made here and the particularly strong GDS of MY34. This suggests that physical or chemical processes in martian dust storms may trigger the release of reactive gas-phase chlorine from the material that constitutes the airborne dust. Chlorine is widespread at the surface (22), and in the martian dust, at levels reaching 1 % by weight (23). This chlorine may be present as halite (NaCl), a mineral observed in nakhlite meteorites that originated from Mars (24) and proposed to be the dominant form of chloride on the martian surface in certain areas observed from orbit (25). Alternatively, perchlorate (ClO4) has been observed on the martian surface at high and low latitudes (26, 27) and should be widely distributed (28). During a dust storm event, both of these forms of Cl may be lofted into the atmosphere, making chlorine readily available in the lower atmosphere at this time. Releasing gas-phase chlorine from chloride salts may involve hydration of the chlorine salts, which has been shown to be effective in martian conditions (29). This can be followed by oxidation reactions and the release of radicals. The latter mechanism remains speculative at martian conditions but would ultimately lead to the formation of HCl (30).

In detail, four different pathways can be considered: (i) As the GDSs, and that of 2018 in particular, are characterized by large H2O mixing ratios up to very high altitudes (11, 12, 31), unusually strong concentrations of oxidants such as OH and HO2 should be expected in the atmosphere. In this case, particularly efficient gas-surface oxidation processing of the dust aerosols during the GDS may release reactive chlorine, as is the case on Earth (1, 30). This scenario is supported by a strong correlation between the observed HCl and H2O profiles (see fig. S7). A simultaneous observation of elevated HCl, H2O, and aerosols, which are governed by the same advection pattern, does not constitute direct evidence of a cause-and-effect relation between them. However, the detection of a sudden appearance of HCl only in the presence of dust (furthermore during unfavorable viewing conditions caused by the dust-rich environment) provides strong indirect support for this hypothesis.

(ii) Chlorine would be more efficiently released from dust via acidic oxidation, analogous to terrestrial processes. The availability of necessary acids in the martian atmosphere remains unknown, but photochemical modeling studies (32, 33) have demonstrated that the presence of nitrates, identified on the martian surface (34) and a likely component of dust, should enable the production of acids, nitric acid (HNO3), and peroxynitric acid (HNO4). They oxidize dry chloride salts to make Cl2 gas, which would rapidly photolyze to generate chlorine radicals (35), which then react with HO2 (primarily) to form HCl.

(iii) Because of strong saltation processes, the GDS can mobilize dust grains that have not been previously exposed to UV light for long periods. Being lifted to high altitudes, chlorine-bearing molecules at the surface of airborne dust may break up under the effect of UV irradiation into gas-phase compounds, including chlorine. The potential to oxidize mineral chlorides by the action of UV radiation has been demonstrated in the laboratory (36), but more experimental work is required to determine the abundance of chloride radicals that could be released to the gas phase by such processes.

(iv) Chlorine could be released by the volatilization of chloride minerals by electrical discharges in the dust storm, as demonstrated in laboratory experiments under simulated martian atmosphere conditions (3739).

The decline in HCl, observed by ACS in MY35, is also indicative of an unexpected chemical sink for that species, which, in terms of the conventional gas-phase chemistry, is the stable reservoir of chlorine in the lower atmosphere of Mars (40). The transient nature of the observed HCl tells us that this does not constitute the whole picture and that we are missing an important chemical or physical loss process of chlorine. On Earth, laboratory studies have demonstrated the strong uptake coefficient of HCl on water ice surfaces at temperatures typical of those encountered on Mars (41, 42). Water ice clouds are detected in our occultations during the whole dusty period, overlaying the dust, and, later, at lower altitudes, where we see HCl (12, 43). In addition, surface frost is at a maximum at LS = 270 (northern winter), when our northern HCl values are smaller. Heterogeneous HCl loss on surface ice would also be compatible with the shape of the profiles shown in Fig. 2 (A and C), showing decreasing mixing ratios near the surface.

Although our data do not permit a definitive determination of the source of HCl at this time, the coincidence of the GDS leads us to propose a novel surface-atmosphere interaction made plausible by terrestrial chemistry and recent laboratory studies. General circulation modeling is needed to constrain rates of HCl production and destruction and to probe possible sources of surface venting. The apparent link to dust activity will be examined during future dust events. Regardless of the HCl origin, it appears unlikely that the processes responsible for its production and destruction would not affect the rest of Mars atmospheric chemistry. An impact on other gases is expected at altitudes above 30 km, where a greater fraction of chlorine is in the form of atomic Cl. The peak HCl concentrations on Mars ~1 to 4 ppbv are comparable to those in Earths upper stratosphere and mesosphere (44). On Mars, the destructive ozone cycle, including odd oxygen, well known in Earths stratosphere (45), would be ~20 times more efficient than assumed with previous upper limits on HCl. On the other hand, the transient nature of the HCl enhancement detected by ACS suggests the existence of a strong and unexpected loss process of that species, likely heterogeneous and efficient in the lower atmosphere or at the surface of Mars. Such a pathway may be photochemical and related to the advection pattern of other gases, such as H2O, or to the absorption by dust itself (46). Our discovery suggests that the martian photochemistry should be revised, considering reactions with atmospheric dust or surface outgassing.

The ACS instrument is a collection of three spectrometers operating in nadir and SO mode. The work presented here uses the ACS mid-infrared (ACS MIR) channel, which is a cross-dispersion echelle spectrometer. Solar light is dispersed by an echelle grating to measure the spectrum in the infrared range with high spectral resolving power (/ ~ 30,000). Overlapping diffraction orders are then separated by a steerable secondary diffraction grating, the position of which determines the instantaneous spectral range (7). In this study, we use secondary grating positions 11 and 12, which provide spectral ranges of 2678 to 2948 cm1 and 2917 to 3235 cm1, respectively, and divided into 16 to 20 diffraction orders. The diffraction orders related to the fundamental rotational band of HCl are shown in fig. S1, along with the contributions to transmission spectra by the absorption of CO2, H2O, HDO, and HCl. The partial overlap of the instantaneous spectral range in positions 11 and 12 permits measuring diffraction orders 173 to 175 in both positions. Figure S2 shows fits to HCl lines from both grating positions, in orders not presented in Fig. 1.

An ACS MIR detector image is a two-dimensional array of measured intensities. The x axis corresponds to wave number calibration, and the y axis corresponds to both the diffraction order and the tangent height of the instantaneous field of view (IFOV) (7). The appearance of a frame is several brightness stripes approximately 20 pixels wide, each one corresponding to a diffraction order in the mid-infrared (14). The IFOV covers 1 to 4 km, and each row provides a unique spectrum, separated by ~0.1 km.

Processing of the detector images was carried out at the Space Research Institute of the Russian Academy of Sciences (IKI RAS). A set of corrections is applied to each data frame that includes masking hot pixels, accounting for a subpixel drift in position caused by the instruments thermal state, and an orthorectification. A dark image (Idark) accounting for dark current and thermal drift is computed from the observations made when the sun is fully obscured. A solar reference image (Isun) is computed by stacking observations made at tangent heights from 80 to ~250 km. For the spectral range provided by secondary grating positions 11 and 12, 80 km is sufficiently high to be free of gaseous absorption. The transmission at each altitude z is computed from the observations I(z) as (I(z) Idark)/(Isun Idark). Additional details can be found in (1214, 47).

In ACS MIR, there is an effect, possibly caused by an optical component being damaged during launch, that results in the image of gaseous absorption lines to appear doubled. Rows for analysis are chosen by identifying the edge of the detector slit closest to the center of the solar disk, where this effect is minimized (a small shoulder is visible in spectra shown in fig. S2) (10, 13, 14). An instrument line shape can be modeled that accounts for this feature, and we have shown that it can be used to accurately retrieve trace gas abundances by validating results against those obtained from simultaneous observations made by the near-infrared (NIR) channel of ACS (9, 10, 12, 13). Wave number calibration is performed for each row in two steps: first, by comparing the solar reference spectra to that measured by the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) (48), and then, by comparing strong gas absorption lines, when available (13). Lastly, spectra are normalized using an alpha hull method (49).

Spectral fitting was performed using the Jet Propulsion Laboratory Gas Fitting Software suite (GGG or GFIT) (5052). The atmosphere is modeled as homogeneous layers of 1-km thickness, and the optical path through each layer along the LOS is computed. For each fitting interval and for each spectrum, a forward model is computed using the instrument line shape described above and a Voigt line shape that depends on temperature and pressure and broadening parameters taken from the 2016 version of HITRAN line list (53). Vertical profiles of temperature and pressure were retrieved from CO2 absorption features in simultaneous observations made by ACS NIR (12). The line depths are related to a gas mixing ratio through the Beer-Lambert law, which depends on the line strength, taken from HITRAN 2016, the line shape, the temperature, and pressure of the atmosphere, and the optical path length. Vertical profiles of trace gas volume mixing ratios (VMRs) are estimated by inverting a matrix of LOS column abundances with a matrix of atmospheric layer contributions along the optical path. Uncertainties are computed from the Jacobian matrix of partial derivatives.

ACS results have been confirmed by two other analysis streams developed at the IKI and the Laboratoire Atmosphres, Milieux, Observations Spatiales (LATMOS) in support of the Mars Express Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars instrument (31, 54). The IKI code uses a Levenberg-Marquardt iterative approach to find the best solution for the gaseous composition of a model atmosphere, followed by applying Tikhonov regularization of the profile. This code has been adapted and used with ACS MIR (9) and ACS NIR (12) data. The LATMOS code uses a Levenberg-Marquardt regression scheme applied to transmittance spectra to infer the LOS integrated quantities of gases (47). The VMR is obtained by rationing the simultaneous observations of the targeted species (HCl in that case) with that of CO2 calculated from fitting its 628 isotope Q branch in diffraction order 178. Derived gaseous vertical profiles are subsequently smoothed by convolving with a 1-km Gaussian kernel.

Detection limits have been estimated by measuring the noise of each spectrum and then performing spectral fitting with fixed quantities of HCl until modeled lines become prominent enough to cross a threshold value. The noise is measured by computing the difference between a spectrum and a smoothed spectrum. A smoothing window sufficiently wide to capture the variability of the signal caused by both random noise and larger systematic features is used, resulting in an SD of the noise that is consistent with that of the residuals of good spectral fits. A modest 2 SD threshold from a mean spectrum baseline value was used. The mean values, 1 and 2 SD thresholds, best-fit lines, and modeled spectra are shown in fig. S5 (A and B) for diffraction orders 174 and 175. The mean detection limit for these two orders, common to grating positions 11 and 12, is used to compute vertical profiles of detection limits, a selection of which are shown in fig. S5C. This method results in larger, more modest detection limits, appropriate for a gas that is now known to be present, than using the retrieval uncertainties. It is also more robust, as a best-fit line can occasionally suggest a negative gas value, which results in larger oscillation in a vertical profile of retrieval uncertainties. In total, 643 occultations have been analyzed in Fig. 3.

NOMAD is a set of spectrometers operating in the spectral ranges between 0.2 and 4.3 m consisting of three channels. HCl has been observed with the SO channel, which uses an echelle grating used in combination with an acousto-optic tunable filter (AOTF) that selects the diffraction orders to be recorded (8, 55). The diffraction order can be changed instantaneously by altering the frequency applied to the AOTF, and so, the SO channel is able to measure any five or six selected diffraction orders per second within the entire spectral range of the channel. The illuminated rows on the detector are split into four individual bins, and a spectrum is recorded for each bin in every diffraction order from the top of the atmosphere (~200 km) to near the surface. Wave number calibration uses gaseous absorption lines, and a correction is applied to account for pixel nonlinearities.

For this work, SO channel data measured between April 2018 and February 2020, spanning both hemispheres, were analyzed. HCl features should be observed in several orders (125 to 130), and orders 129 (2889 to 2921 cm1) and 130 (2920 to 2943 cm1), which have been regularly observed, have been used to detect HCl. These datasets represent in total 264 observations in which 36 are positive detections. A positive detection is a 5- retrieved VMR for which the weighted average of the bins is greater than 0.3 ppb at more than two tangent heights ( is the SD of the mean of retrievals from the four bins).

The HCl mixing ratio is retrieved by fitting the entire spectral range of either order 129 or 130. The temperature, pressure, and CO2 VMR are taken from the values predicted by the GEM-Mars model (56) for each altitude, taking into account the GDS (17). Computed spectra are convolved with an instrument line shape, and the forward model accounts for the effects of the AOTF and the grating. Retrievals are performed using an optimal-estimation approach and line-by-line radiative transfer code (ASIMUT) developed for planetary atmospheres (57). Retrievals are performed independently at each tangential altitude (11). Figure S3 shows examples of bin-averaged spectra and best-fit lines for orders 129 and 130 featuring HCl absorption lines.

D. C. Catling, M. L. Smith, M. W. Claire, K. J. Zahnle, paper presented at the EPSC, London, UK, 2013.

F. Lefvre, V. Krasnopolsky, The Atmosphere and Climate of Mars, R. M. Haberle, R. T. Clancy, F. Forget, M. D. Smith, R. W. Zurek, Eds. (Cambridge Planetary Science, Cambridge University Press, 2017), pp. 405432.

J. B. Burkholder, S. P. Sander, J. P. D. Abbatt, J. R. Barker, R. E. Huie, C. E. Kolb, M. J. Kurylo, V. L. Orkin, D. M. Wilmouth, P. H. Wine, Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies: Evaluation Number 18, (Technical Report, Jet Propulsion Laboratory, NASA, 2015).

G. P. Brasseur, S. Solomon, Aeronomy of the Middle Atmosphere: Chemistry and Physics of the Stratosphere and Mesosphere (Atmospheric and Oceanographic Sciences Library, Springer Netherlands, ed. 3, 2005).

Originally posted here:

Transient HCl in the atmosphere of Mars - Science Advances

On Earth, the study of ice core samples is one of many methods scientists use to reconstruct the history of our past climate change. The same is true of Mars northern polar ice cap, which is made up of many layers of frozen water that have accumulated over eons. The study of these layers could provide scientists with a better understanding of how the Martian climate changed over time.

This remains a challenge since the only way we are able to study the Martian polar ice caps right now is from orbit. Luckily, a team of researchers from UC Boulder was able to use data obtained by the High-Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter (MRO) to chart how the northern polar ice caps evolved over the past few million years.

The research was conducted by Andrew Wilcoski and Paul Hayne, a Ph.D. student and assistant professor from the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder. The study that describes their findings recently appeared in the Journal for Geological Research (JGR), a publication maintained by the American Geophysical Union (AGU).

For the sake of their study, Wilcosky and Hayne sought to determine the current state of the Martian North Polar Residual Cap (NPRC), which is vital to understanding the North Polar Layered Deposits (NPLD). Using the high-resolution images gathered by the HiRISE instrument, Wilcosky and Hayne examined the rough features of the NPRC which includes ripples and ridges of varying size and shape.

They then modeled the growth and recession of NPRC over time based on its interaction with solar radiation and how the rate of growth and loss is affected by the amount of atmospheric water vapor. What they found was that in addition to causing the formation of rough terrain (ripples and ridges) in an ice sheet, exposure to solar radiation will also cause ice to sublimate unevenly.

Basically, Mars axial tilt, which is responsible for it experiencing seasonal changes similar to Earth, also causes one side of these features to sublimate (the Sun-facing side) while the other does not. This has the effect of exaggerating these features, leading to pronounced ridges and valleys that become more pronounced as time goes on.

Overall, the model employed by Wilcoski and Hayne determined that the rough features observed by the MRO should measure 10 m (33 ft) in diameter and 1 m (3.3 ft) deep. Furthermore, their results demonstrated that as the features age, the spatial wavelength (the distance) between each ripple increases from 10 to 50 m (164 ft). As they state in their study:

Our results show that the size of mounds and depressions on the ice cap surface suggest that it took 110 thousand years to form these roughness features. Our results also suggest that the formation of features on the surface may depend on when water vapor is present in the atmosphere over the course of a year (e.g., summer or winter).

These results are consistent with the images taken by the HiRISE instrument of the Martian North Polar Residual Cap (NPRC). What they indicated is that the rough features observed around Mars northern polar ice formed within the last 1000 to 10,000 years, which provides scientists with a starting point for reconstructing the climate history of Mars.

Such is the nature of the Red Planet. Today, scientists have a pretty good understanding of the nature of the Martian landscape and how it changes throughout the year. They also have an idea of what it used to look like billions of years ago, thanks to impeccably-preserved surface features that indicate the past presence of flowing and standing water (rivers, streams, and lakes).

But the intervening period, where the climate transitioned from one to the other, thats where much remains to be learned. In the coming years, robotic missions could be sent to Mars for the sake of studying the ice sheets directly and maybe even return samples to Earth. In the next decade, as astronauts begin to set foot on Mars, the opportunity to explore the ice caps could also be possible.

Further Reading: EOS (AGU), JGR Planets

Like Loading...

More here:

How Old is the Ice at Mars North Pole? - Universe Today

Abstract

Isotopic ratios and, in particular, the water D/H ratio are powerful tracers of the evolution and transport of water on Mars. From measurements performed with ExoMars/NOMAD, we observe marked and rapid variability of the D/H along altitude on Mars and across the whole planet. The observations (from April 2018 to April 2019) sample a broad range of events on Mars, including a global dust storm, the evolution of water released from the southern polar cap during southern summer, the equinox phases, and a short but intense regional dust storm. In three instances, we observe water at very high altitudes (>80 km), the prime region where water is photodissociated and starts its escape to space. Rayleigh distillation appears the be the driving force affecting the D/H in many cases, yet in some instances, the exchange of water reservoirs with distinctive D/H could be responsible.

Mars shows a scarred landscape carved by a wet past [e.g., (1)], yet it is not clear how much of this water ran across the Martian surface or for how long. The debate includes considerations of a wet and cold past scenario [e.g., (2)], wet and hot past [e.g., (3)], or hybrid models [e.g., (4)]. In many cases, these scenarios are stimulated by the strong geological record but depend highly on the assumed atmospheric states and escape considerations. Measurements of isotopic ratios and, in particular, the deuterium to hydrogen ratio (D/H) in water provide a powerful method to constrain volatile escape [e.g., (5)] and to track the transport of water between reservoirs (e.g., seasonal transport between the polar caps). Because the thermal Jeans escape rates for each isotope are different (larger for the lighter forms), over long periods, the atmosphere becomes enriched in the heavy isotopic forms. By mapping the current isotopic ratios, one can also test for the existence of different volatile reservoirs (e.g., polar caps and regolith) with distinct isotopic signatures (6).

The idea of distinct water reservoirs interacting during the water cycle was strengthened by the strong isotopic variations in the water column that were observed across the planet via ground-based astronomy (5, 7). Nevertheless, the D/H ratio is also heavily affected by climatological processes because the vapor pressures of HDO and H2O differ near the freezing point, making the condensation/sublimation cycle of the isotopologs sensitive to local temperatures, to saturation levels, and to the presence of aerosol condensation nuclei. This would lead to strong seasonal D/H gradients, while local orography and cloud formation would lead to longitudinal variability.

By performing high-resolution infrared spectroscopic observations across the entire planet, the ExoMars Trace Gas Orbiter (TGO) provides an unprecedented view of the three-dimensional structure and composition of the Martian atmosphere. Specifically, the NOMAD (Nadir and Occultation for Mars Discovery) (8, 9) instrument suite aboard TGO has the capability to provide vertical profiles and global maps of water (both H2O and HDO), water ice, and dust using high-resolution infrared spectroscopy. The vertical and seasonal trends in water vapor during the global and regional dust storms of Mars Year (MY) 34 were extensively presented (10), while the present work emphasizes the relationship between water abundance and the D/H ratio based on data acquired with the SO (solar occultation) channel of NOMAD between April 2018 (the start of science operations) and April 2019. This interval corresponds to Ls = 162.5 of MY 34 to Ls = 15.0 of MY 35 and included the global dust storm (GDS) that engulfed the planet in MY 34 (June to September 2018). A total of 219,464 individual SO spectra through the Martian atmosphere were collected during 1920 occultation events.

ExoMars TGOs near-polar orbit with up to 24 occultations per sol, shared between NOMAD and Atmospheric Chemistry Suite (11), permits high-cadence mapping of the variability of water and D/H over time. Sensitivity typically allows water mapping up to an altitude of ~100 km for the main isotopolog of water (H2O) and up to ~50 km for HDO and, thus, D/H (with a typical resolution of ~1 km), while high opacity from aerosols and airborne dust restrict the lower boundary to 5 to 10 km. The SO channel operates at wavelengths between 2.2 and 4.3 m (2325 to 4500 cm1) using an echelle grating, combined with an acousto-optic tunable filter (AOTF) and delivers a spectral resolving power of ~20,000. The width of each AOTF filtered order varies from 20 to 35 cm1, linearly increasing with the diffraction order number. The infrared channels (SO and nadir channel) of the NOMAD instrument are described in detail in previous works (1215), while a complete calibration using the in-flight data acquired before the science phase has been discussed in depth (16).

During an occultation, the SO instrument is pointed toward the Sun to observe the solar radiation as attenuated by the Martian atmosphere at different altitudes, enabling an investigation of the atmospheric vertical structure. On a typical occultation, five or six different diffraction orders are sampled at 1-s intervals, with H2O sampled in two or more diffraction orders and HDO in one of them, ultimately allowing quantification of D/H for almost all NOMAD occultations (see example spectra in Fig. 1). The possibility to access different absorption bands of water is of great benefit to achieve measurement accuracy throughout a vast range of altitudes since absorption regimes vary with the observed atmospheric column. For instance, strong fundamental bands of H2O (such as the v3 band at 2.7 m, orders 168 to 170) probe water up to 120 km but become saturated at ~50 km, while the weaker 22 band at 3.3 m (orders 133 to 136) probes deeper into the atmosphere without saturation.

The observations were taken during the GDS and show that the two bands (1 of HDO and 22 of H2O) have similar opacities and, therefore, comparable curves of growth and altitude sensitivity.

We derived H2O and HDO slant column densities from the resulting spectra by using Goddards Planetary Spectrum Generator (PSG) (17), which is based on an optimal estimation approach (18), modified with an extra regularization parameter (19, 20). For Mars, PSG ingests a specific line compilation for water and its isotopologs, tailored for a CO2-rich atmosphere (21, 22). The derivation of molecular mixing ratios does depend on the assumed pressure/temperature profiles, and in particular, the local atmospheric density and temperature can vary during perihelion season, depending on the intensity of heating introduced by dust present in the atmosphere. Because portions of the dataset were acquired during the GDS, the a priori atmospheric state has to be representative of those specific conditions. We calculated that using the Global Environmental Multiscale (GEM)Mars model (23, 24) and a specific dust storm scenario that reproduces the dust state of the atmosphere during MY 34. The properties of the GEM-Mars GDS model during the storm differ substantially from the average climatology of the Mars Climate Database (v5.2) (25), with temperature deviations as large as 30 K modeled in the middle atmosphere (fig. S4). The largest discrepancies are found in the southern hemisphere, where dust concentrations are greater during the GDS. The dust abundance or the assumed aerosols profiles do not affect the H2O and HDO SO retrievals directly (only when the atmosphere is fully optically thick). Dust will tend to heat the atmosphere, and that may reflect in enhanced partition functions, which ultimately affect the retrieved molecular densities. On the other hand, this effect is particularly small for the retrieved D/H since both partition functions vary similarly to temperature, so this systematic effect is removed when computing D/H.

To compute a single molecular profile per occultation, measurements are first collected to form a single dataset colocated in altitude (typically one to two orders for H2O and one to two orders for HDO) and then aggregated by a weighted mean. Each molecular retrieval is assumed to be independent from the nearby altitude retrievals, with the resulting uncertainty also including the standard deviation of the measurements (see figs. S6 and S7). The D/H ratio is determined using the same approach: For each occultation and altitude, the D/H is computed using the weighted averages of H2O and HDO. Uncertainties were computed using standard optimal estimation statistics that are further corrected for the quality of the residual spectra (chi-square of the fit). Measurements from several orders and computation of uncertainties of D/H were performed using standard error propagation methods [see also (5, 9)].

The retrievals were organized by season and latitude to investigate the main processes acting on water and D/H. As shown in Fig. 2, the water vapor abundances change markedly across the year, with D/H also showing important changes. Previous measurements of water columns [e.g., (2630)] also report great seasonal, temporal, and spatial variability, with strong enhancements during the summer hemisphere as reported here. The seasonal variability reported here should be viewed with caution since the orbit of ExoMars causes seasonal and latitude changes to be convolved (Fig. 2, top). Note that these are local D/H values at a specific altitude (not of the column), and they can be only understood in the context of the local climatology at this specific altitude/latitude/longitude/season.

Only H2O values with sigmas lower than 15 parts per million by volume (ppmv) and D/H values with sigmas lower than 0.8 VSMOW are shown (point-by-point error bars are presented in fig. S7). Because of the ExoMars/TGO orbit, there is an intrinsic relationship between the seasonal and latitudinal sampling for the occultations, and the latitude subpanels indicate which latitudes are sampled during a particular instance. Water is observed to reach the upper regions of the atmosphere (>80 km) during indicated events: (i) during the GDS, (ii) during the regional dust storm, and (ii) during southern summer, in which we observe a localized upper atmosphere water excess.

Consistent with earlier studies of dust storms (10, 31), we found that water vapor abundances in the middle atmosphere (40 to 100 km) increased substantially during the GDS (June to mid-September 2018) and the regional dust storm of January 2019. In particular, water vapor reaches very high altitudes, at least 100 km, during the GDS. A General Circulation Model simulation explained that dust stormrelated increases in atmospheric temperatures elevate the hygropause, hence reducing ice cloud formation and so allowing water vapor to extend into the middle atmosphere (24). We confirm that (i) water vapor also reaches very high altitudes during the southern summer solstice, independently of dust storms [see lower dust content during this period as reported in (32)] and (ii) that water drops to very low values at high/low latitudes and close to equinox with the hygropause subsiding to a few scale heights. With regard to D/H, we observe the following distinct features: (i) the D/H ratio is typically ~6 VSMOW (Vienna Standard Mean Ocean Water) in the lower atmosphere, (ii) the D/H ratio decreases with altitude, as observed similarly on Earth (22), and (iii) the D/H ratio is low (2 to 4 VSMOW) at high/low latitudes and close to equinox where H2O is low.

Within half an MY, we observed three instances (the GDS, southern summer, and the regional dust storm) of water vapor reaching the upper atmosphere, where it can be readily photolyzed (24), bypassing the traditional H2 diffusion limitations on water escape rates (33). The D/H ratio is probably quite low at these high altitudes if we attempted to extrapolate our D/H values to 70 to 80 km from the low/middle atmosphere (50 to 60 km), yet photolysis, vertical transport, and other processes may lead to great variability at these altitudes. On Earth, mesospheric D/H measurements show strong variability (34), which has been attributed to the differential photolysis rates of HDO and H2O combined with atmospheric transport and CH4/CH3D photochemistry. For the lower atmosphere, the decrease of the D/H with altitude can be explained, as on Earth, by Rayleigh fractionation (22). The fractionation in the troposphere of Earth has been shown to be also strongly dependent on atmospheric dynamics [e.g., see convective/subsiding results in (35) and formation of clouds and atmospheric microphysics in (36)], resulting in highly variable deuterium enrichments with respect to altitude, time, and position on the planet [e.g., (37, 38)]. These may explain the localized behavior and variability in the D/H ratio observed across Mars, and it is consistent with the column variability observed in (5).

To explore the 3D structure of the water cycle and the D/H signatures, we aggregated the data into seasonal periods and computed latitude versus altitude plots of water vapor and D/H (Fig. 3). These plots show a marked variability of the vertical profiles of water and D/H, with clear and defined latitudinal structures. As also shown in (10), the increase of the water vapor abundances at higher altitudes is remarkable for the global (Ls = 190 to 210) and regional dust storm (Ls = 320 to 330), yet this excess water is only confined to equatorial and mid-latitudes (<60). Although the atmosphere is filled with water to high altitudes during these times, the D/H remains relatively low (4 to 5 VSMOW) and increases to ~6 VSMOW only at high latitudes (away from the subsolar point) and low altitudes. In principle, this is expected and could be an indication of Rayleigh fractionation and cloud formation (9), where D/H is actually decreasing with altitude, but it is only measured with sufficient signal-to-noise ratio (low opacities) at high altitudes (>40 km) in mid-latitudes and at low altitudes (10 to 40 km) in high latitudes.

Only H2O values with sigmas lower than 15 ppmv and D/H values with sigmas lower than 1.5 VSMOW are shown. The panels clearly show the evolution of the water cycle across these complex events, revealing marked changes in the water and D/H distributions across the events. The sparsity of valid D/H datasets considering this fine temporal sampling does not allow us to fully capture every detail of the latitude by altitude variability, yet two points are clearly observed: (i) The water released from the southern polar cap has a distinctive 6- to 7-VSMOW enrichment in D/H, and (ii) during southern fall (Ls 300 to 320 and Ls 330 to 360), the hygropause is compacted in the southern hemisphere, leading also to very low D/H at these latitudes and season.

The injection of southern polar cap water with enhanced D/H is clearly seen as southern spring progresses to summer. Between Ls = 270 and 300, we see water vapor increasing in the southern hemisphere and also in altitude as we approach the polar latitudes [labeled in Fig. 2 as aspirator (from the Latin word aspire to rise, climb up)]. The D/H remains high (>6 VSMOW) for most of this water (probably coming from the seasonal southern polar cap) and decreases to <4 VSMOW at higher altitudes. Fractionation is also present at this season, associated with a more compact hygropause in the colder/winter hemisphere and a more compact D/H profile. As we move to southern fall (Ls = 300 to 320), the water may have been transported to equatorial latitudes, which is then puffed into higher altitudes during the regional dust storm (Ls = 320 to 330). During the regional storm, water reaches only 60 km in altitude, in comparison to 80 to 100 km observed during the GDS. Water abundance then collapses to low values and at low altitudes during southern fall (Ls = 330 to 360) and early northern spring (Ls = 360 to 370, MY 34). The D/H information during this period is inconclusive since water is confined to low-altitude layers of the atmosphere, where long atmospheric path lengths prevent observations of HDO with sufficient sensitivity due to aerosol extinction. During this season, we do observe low D/H values in the southern hemisphere and very low values at low altitudes.

Multiple reservoirs have been identified to account for the current inventory of water on Mars, ranging from the observable polar layered deposits (39, 40) to ice-rich regolith at mid-latitudes (41, 42), near-surface reservoirs at high latitudes (43), and subsurface reservoirs, as implied by gamma ray and neutron observations (44). If each of these reservoirs has a distinct isotopic content, then the signature of the exchange between these reservoirs should be present in the observed atmospheric D/H ratio variation. The outstanding question is whether each reservoir has or should have a distinct isotopic signature. The fact that Mars has had marked variations in its obliquity (45), changing from ~45 to 15 in the last million years, would suggest that the polar caps are relatively new and that all the water reservoirs should have been mixed within the last 10 million years. Considering that it takes billions of years for notable changes in the D/H ratio to take effect, the different reservoirs may have the same isotopic signature, yet this hypothesis assumes that all labile water is mixed by the hydrological cycle. A testable way to prove this hypothesis would be to ultimately probe the water D/H in the polar caps below the seasonal layers. We then ask, is the variability that we observe related to different reservoirs?

As on Earth (46), D/H on Mars shows great variability in time and space, consistent with previous column integrated reports in (5, 47). Observations using SOFIA (Stratospheric Observatory for Infrared Astronomy) at thermal wavelengths (48) do also report variability yet much more subdued. Thermal observations are more affected by the assumed temperature profiles and thermal contrast, and the spatial resolution of SOFIA observations is typically only four to five pixels across Mars disk; however, it is interesting to note this difference between SOFIA and other results. In particular, there may be an annual element to this hemispheric variability of the observed D/H column. Strong isotopic anomalies are typically observed at regions with strong temperature/water gradients, like the polar caps, and these are typically hard to capture and sample at moderate spatial resolutions from the ground.

In many cases, the observed variations of the D/H across seasons and with altitude revealed by our work could be attributed to Rayleigh fractionation and cloud formation (32), with the D/H decreasing with altitude and dropping or decreasing at the edge of the hygropause. In the zonal mean Fig. 3, the seasonal water being added from the southern polar cap during southern summer (Ls = 210 to 250 and 270 to 300) has a ~6- to 7-VSMOW value, consistent with the column values measured in (5) for the northern pole water. This would perhaps mean that the two main reservoirs of water on Mars, the polar caps, share a common value of D/H, yet the south polar cap only has seasonal water ice, not permanent. The lower values in D/H observed during southern fall (Ls = 300 to 320 and 330 to 360) at the southern latitudes would imply that a large fraction of the HDO was sequestered. This could be associated to be a rapid collapse of the hygropause at these latitudes, which leads to a steep Rayleigh fractionation condensation profile. The existence of water ice clouds during this period and season (31, 32) is consistent with this view.

Further interpreting the results, in particular, the concept of multiple reservoirs of water with a distinctive D/H and water escape would require detailed comparisons with a highly parameterized weather and climate model. The model would need to have a comparable prescription of the water and aerosol distribution and to have a realistic heterogenous water fractionation model to fully capture the observed D/H variability and advance current models (4951). The ultimate question is then what is the representative D/H of labile water on Mars right now? If we assume that the observed fractionation is driven mainly by Rayleigh distillation, then the observed maximum D/H values of 6 to 7 VSMOW observed in this work are then descriptive of the truly intrinsic water D/H when both isotopologs are fully vaporized. This value is consistent with previous findings as reported above and would further establish that Mars has lost a substantial amount of water (>137-m global equivalent layer) (5). The fact that we observe three instances during a single MY where water is brought to the upper regions of the atmosphere (>60 km; Figs. 2 and 3) would provide the means for this escape to take place.

W. Darling, G, A. H. Bath, J. J. Gibson, K. Rozanski, Isotopes in water, in Isotopes in Palaeoenvironmental Research, M. J. Leng, Ed. (Springer, 2006), pp. 166.

K. Stamnes, G. E. Thomas, J. J. Stamnes, Radiative Transfer in the Atmosphere and Ocean (Cambridge Univ. Press, 2017).

See original here:

Water heavily fractionated as it ascends on Mars as revealed by ExoMars/NOMAD - Science Advances

NASA will use a "sky crane" to gently lower Perseverance to the surface of Mars.

When it comes to spacehappenings, few things are as thrilling as landing a vehicle on another planet. It's tense. It's exciting. It's high stakes. On Feb. 18, NASA's Perseverance rover will aim to stick the landing on Mars, kicking off a new era in red planet exploration.

While NASA has a lot of experience with delivering machines to Mars (here's looking at you, Curiosity and InSight), that doesn't make it any easier this time. "Landing on Mars is hard," NASA said. "Only about 40% of the missions ever sent to Mars by any space agency - have been successful."

It's going to be a wild ride. Here's what to expect on Perseverance's landing day.

From the lab to your inbox. Get the latest science stories from CNET every week.

NASA will provide live coverage of the landing. The NASA TV broadcast from mission control kicks off on Thursday, Feb. 18 at 11:15 a.m. PT. Touch down in the Jezero Crater on Mars is scheduled for around 12:30 p.m. PT.

This won't be like a rocket launch where we get to see every detail as it's happening. We will get NASA commentary and updates, views from mission control, and hopefully some images not too long after landing. It will be a must-watch event for space fans.

We've been to Mars before. So why all the hype? The red planet is our solar system neighbor. It's rocky like Earth. It has a long history of water. We can imagine ourselves perhaps living there some day.

"The level of interest that people have in this planet is just extraordinary," Alice Gorman-- space archaeologist and associate professor at Flinders University in Australia -- told CNET. Gorman highlighted humanity's search for life beyond Earth and how Mars is a candidate for having hosting microbial life in its ancient past.

There's also something special about a rover, a wheeled mechanical creature with a "head" and "eyes." "People feel towards the rovers because they're active and they move," said Gorman, likening it an almost parental sense of attachment. The outpouring of emotion over the demise of NASA's Opportunity rover proves how connected humans can get to a Mars explorer. Perseverance is set to become our new Martian sweetheart.

Mars arrivals are always harrowing. NASA calls the process EDL for "entry, descent and landing."

"During landing, the rover plunges through the thin Martian atmosphere, with the heat shield first, at a speed of over 12,000 mph (about 20,000 kph)," said NASA in a landing explainer. There's a reason NASA describes the landing process as "seven minutes of terror."

This NASA graphic shows the entire entry, descent and landing (EDL) sequence.

Small thrusters will fire to keep the rover on track on the potentially bumpy ride through the atmosphere. The rover's protective heat shield helps to slow it down. At an altitude of around 7 miles (11 kilometers), asupersonic parachute will deploy and Perseverance will soon separate from its heat shield.

NASA gave a briefing on Jan. 27 with a detailed rundown on the entire EDL sequence, including the "sky crane" maneuver, which lowers the rover the final distance to the surface using a set of cables.

If all goes well, Perseverance will end up standing on the surface of Mars. "The really hard part is to soft land and not crash land, and then to deploy the moving parts," said Gorman. Perseverance is not alone on the trip. It also carries a helicopter named Ingenuity in its belly. Ingenuity will be unleashed later in the mission.

Now playing: Watch this: How NASA's Mars helicopter could change the future of...

5:20

The mission is equipped with cameras and microphones designed to capture the EDL process, so we can expect to both see and hear the excitement of the landing at some point. "It will be the raw sounds of the descent and coming onto the surface," said Gorman. "So that's a whole other level of sensory engagement."

It takes time to send data between Mars and Earth. For us back home, we can expect a first photo not too long after landing, but the full visual and audio experience may take a few days for NASA to share with the world.

The agency released an arrival trailer in December that shows an animated, sped-up version of the process. You'll get the idea of just how wild it is to land a rover on another planet.

Gorman is excited about getting visuals of the rover's landing spot in Jezero Crater. It will be our first close-up look at the landscape in an area that had a history of water. Perseverance hopes to explore that history and look for evidence of life.

While the photos, sounds, helicopter and all-around science will be reasons to celebrate, there's the big lingering question the mission might answer: Was Mars home to microbial life? Said Gorman, "It would just be really great if we've got a bit of a closer handle on whether anything once lived on Mars."

Perseverance is our next great hope in the search for signs of life beyond Earth. It all starts with sticking the landing.

FollowCNET's 2021 Space Calendarto stay up to date with all the latest space news this year. You can even add it to your ownGoogle Calendar.

View post:

NASA Mars Perseverance rover: What to expect on landing day - CNET