NASAs Perseverance rover is lifted during launch preparations at the Kennedy Space Center in Florida. Credit: NASA JPL/Christian Mangano

NASAs Perseverance rover will depart Cape Canaveral Thursday on a $2.7 billion mission to Mars, carrying with it the first interplanetary aircraft, sophisticated instruments to search for signs of ancient life, and drill to core samples for eventual return to Earth.

Building on past discoveries at the Red Planet, the nuclear-powered robot will aim to become NASAs ninth mission to land on Mars, and the first since the Viking landers of the 1970s charged with seeking evidence of life.

NASAs Perseverance rover the centerpiece of the agencys Mars 2020 mission is set for launch Thursday from Cape Canaveral during a two-hour window opening at 7:50 a.m. EDT (1150 GMT). A United Launch Alliance Atlas 5 rocket will fire the spacecraft away from Earth with a relative velocity of24,785 mph, or about 11 kilometers per second.

Thats enough speed to break free of Earths gravitational grip and speed toward Mars, aiming for the point in space where the Red Planet will be Feb. 18, 2021, the Mars 2020 missions designated landing date.

Preparations for the launch have continued despite some slowdowns due to the coronavirus pandemic. The Mars 2020 mission must launch before mid-August, or else face a costly two-year delay until the next time Earth and Mars are in the right positions in the solar system.

Nearly a decade in the making, the Mars 2020 missions rover weighs more than a ton and hosts seven scientific payloads, a robotic arm, the Ingenuity Mars Helicopter, 25 cameras, and the first microphones to record sound on the Red Planet. NASA says the Mars 2020 mission is the most advanced robotic explorer ever sent into deep space.

A prime science goal of NASAs Perseverance rover is to search for biosignatures, markers left behind in Martian rocks by microbial life forms, assuming they existed. But for the first time, if all goes according to plan, scientists will be able to analyze rock samples gathered by Perseverance in modern laboratories on Earth.

This is the first time in history where NASA has dedicated a mission to what we call astrobiology, the search for life, said NASA Administrator Jim Bridenstine.

Were doing transformative science, said Matt Wallace, the Mars 2020 missions deputy project manager at JPL. Really, for the first time, were looking for signs of life on another planet, and for the first time were going to collect samples that we hope will be part of the first sample return from another planet.

But the scientific payoff to that elusive question will have to wait at least a decade, once samples drilled from Martian rocks by the Perseverance rover come back to Earth. The rover itself carries instrumentation to help scientists choose which rocks to sample, but will not have the ability to confirm on its own whether life ever existed on Mars.

The mission objectives of our effort are to explore the geology of our landing site, to look for signs of biosignatures from the past, said Adam Steltzner, chief engineer on the Mars 2020 mission at NASAs Jet Propulsion Laboratory. We are not a life detection mission. We are looking for signs of past life on the surface of mars. Also, signatures that mars was habitable, and to the degree that is still habitable, where it might be habitable. Our third objective is to prepare a returnable cache of samples, and then fourth is to prepare for future human exploration.

In partnership with the European Space Agency, dozens of rock and soil specimens gathered by the Perseverance rover will be sealed and tagged for return to Earth.

Assuming Perseverances mission is a success, and funding and technical plans remain on track, NASA and ESA could launch missions as soon as 2026 with a European-built Mars rover to retrieve the specimens and deliver the material to a U.S.-supplied solid-fueled booster to shoot the samples from Mars into space.

A separate spacecraft provided by ESA will link up with the samples in orbit around Mars, then head for Earth before releasing a NASA re-entry capsule containing the Martian material to complete the first round-trip interplanetary mission no earlier than 2031.

Then scientists will get to work analyzing the samples. They will look for chemical signatures in the core samples that might suggest life once existed on Mars.

Among other objectives, NASAs two Viking landers carried instruments to search for signs of life on Mars when they landed on the Red Planet in 1976. But the robotic landers did not produce any verifiable confirmation of life, andMars missions since Viking have followed the trail of water, seeking evidence that the Red Planet once harbored environments that could have supported basic life forms.

After the dual successes of the Viking landers, NASAs next mission to the Martian surface was Mars Pathfinder, which deployed a small rover just 26 inches (66 centimeters) long named Sojourner in 1997. That mission proved NASA, and more specifically engineers at the Jet Propulsion Laboratory, could build mobile robots to explore the Red Planet.

Next came the larger Spirit and Opportunity rovers, which landed at two different sites on Mars in 2004.

Spirit and Opportunity together established that Mars truly was habitable, that it had abundant water on the surface in many forms, in the forms of large lakes, small lakes, flowing rivers, even hot springs, said Jim Watzin, director of NASAs Mars exploration program. So with that knowledge in hand and the experience that we gained in operating the Spirit and Opportunity, we went and developed what has been our flagship to date, and thats the Curiosity rover.

Curiosity carried a more comprehensive set of instruments to Mars, including a drill to collect pulverized rock samples and deliver the material to a miniaturized laboratory. Curiosity launched in 2011 and landed inside Gale Crater on Mars in August 2012, and found rock layers at the landing site that formed in a lake that dried up billions of years ago.

The rover also discovered organic carbon a building block of life inside Martian rocks, and detected that ancient Mars had the right ingredients to support living microbes.

Curiosity is still operating today and slowly climbing higher on Mount Sharp, a 3.4-mile-high (5.5-kilometer) mountain towering above the crater floor.

Amid the series of rover missions, NASA also dispatched two successful stationary landers to Mars.

The Phoenix lander touched down on the northern polar plains of Mars in 2008 and dug into the soil to find water ice just below the surface. NASAs InSight spacecraft arrived on Mars in 2018 to measure the planets seismology and probe its internal structure.

NASA says it spent more than $2.4 billion to design, build and prepare the Mars 2020 mission for launch. With the money budgeted to operate the rover during the trip to Mars, and for around two Earth years (one Mars year) after landing, the total mission is expected to cost around $2.7 billion.

The 2,260-pound (1,025-kilogram) Perseverance rover is about 10 feet (3 meters) long, 9 feet (2.7 meters wide), and 7 feet (2.2 meters) tall.

The rover is mounted on a rocket-powered descent stage that will lower the robot to the Martian surface. That, in turn, is cocooned inside an aerodynamic shell and heat shield to protect the rover during entry into the atmosphere of Mars, when temperatures outside the spacecraft will reach 2,370 degrees Fahrenheit (about 1,300 degrees Celsius).

A cruise stage is attached to the Mars descent vehicle to shepherd the spacecraft along the 300-million-mile (nearly 500-million-kilometer) journey to the Red Planet. The carrier module will jettison before arriving at Mars and burn up in the Martian atmosphere.

The entire vehicle weighs about 9,000 pounds, or nearly 4.1 metric tons, on top of ULAs Atlas 5 rocket, according to a NASA spokesperson.

While any space launch has some risk, landing a spacecraft on Mars is a hazardous proposition. About half of all missions that have attempted to land on Mars have failed, although NASA has succeeded five consecutive Mars landing attempts.

NASAs Perseverance rover is the third mission to Mars to launch this month, following the July 19 takeoff of the Hope orbiter developed by the United Arab Emirates in partnership with scientists at three U.S. universities. On July 23, China launched its Tianwen 1 spacecraft, an all-in-one mission consisting of an orbiter, lander and rover.

The Hope and Tianwen 1 missions are the first probes from the UAE and China to head for Mars.

We welcome more nations taking trips to mars and studying it and delivering the science and sharing the science with the world, said Bridenstine, who became head of NASA in 2018 after his nomination by President Donald Trump. Thats what science is all about, of course, its a very uniting kind of thing.

Bridenstine said he did not see NASA as in a competition with other nations for Mars exploration.

This is our ninth time to go to mMars and land softy and do robotic experiments and discovery, he said. So weve been doing this now for decades successfully, and of course, this mission is, by far, the most sophisticated (Mars) mission ever. So I dont see it as a competition, but certainly we welcome more explorers to deliver more science than ever before, and we look foward to seeing what it is that theyre able to discover.

Orbiters from the United States, the European Space Agency, and India are currently flying around Mars and observing the planet from above.

All three missions will arrive at the Red Planet next February, with the UAEs Hope spacecraft and Chinas Tianwen 1 spacecraft swinging into orbit around Mars. Several months later, Tianwen 1 will release its lander in a bid to descend to the Martian surface and deploy its rover.

If successful, China would become the second country to land and operate a mobile robot on Mars, after the United States.

The Perseverance rover will aim for a direct approach to Mars, heading straight into the planets rarefied atmosphere next Feb. 18. Around 10 minutes before reaching the upper edge atmosphere, the spacecraft will shed the cruise stage that will have guided the rover toward Mars since its launch.

The rovers 14.8-foot-diameter (4.5-meter) heat shield will take the brunt of the energy during the crafts plunge into the atmosphere of Mars. While temperatures outside the heat shield reach more than 2,000 degrees Fahrenheit, small thrusters will adjust the angle of the vehicles trajectory, allowing it to control lift and begin navigating toward its landing site.

Around four minutes after entering the atmosphere, the spacecraft will unfurl a 70.5-foot-diameter (21.5-meter) supersonic parachute at an altitude of about 7 miles, or 11 kilometers. Perseverances parachute is stronger than the one used on Curiosity, and the Mars 2020 mission will employ a new technique to deploy the chute based on the crafts position relative to the target landing site, rather than using a timer.

That will result in a more precise landing, NASA says.

Roughly 20 seconds after deploying the parachute, the heat shield at the bottom of the spacecraft will drop away, allowing a downward-facing guidance radar and cameras to start seeing the Martian surface.

The atmosphere of Mars is much thinner than Earths, so a parachute by itself is unable to slow the spacecraft enough for a safe landing. The rovers descent stage will release the backshell and parachute around 1.3 miles (2.1 kilometers) above Mars. Eight throttleable thrusters will further slow the rovers descent from about 190 mph (306 kilometers per hour) to a speed of near zero just 66 feet (20 meters) above the surface.

During this time, advanced guidance software loaded into the rovers flight computer will begin searching for a smooth place to set down. The new capability, named terrain relative navigation, was developed since Curiositys landing in 2012 and will be used on Mars for the first time with Perseverance.

It works by comparing imagery taken in real-time during descent with a map of steep slopes, boulders and other hazards pre-loaded into the computer using pictures captured from Mars orbiters. If the rover sees it is heading for dangerous terrain, it will adjust its path to reach a smoother area.

Finally, a bridle will lower the one-ton Perseverance rover to the surface of Mars using a technique called the sky crane, which engineers invented and demonstrated on the Curiosity rovers landing in 2012. Once the rovers six wheels touch Mars, the bridle will be cut and the descent stage will fly away to crash a safe distance away.

That all happens millions of miles from Earth, when it takes minutes for a radio signal to travel between the planets at the speed of light. That leaves no opportunity for human input once the descent begins.

Its basically a controlled disassembly the whole way, Wallace told Spaceflight Now. Its, by far, the highest risk phase of the mission still, and we had the good fortune on Mars 2020 to have leveraged the system that we designed on Curiosity.

So not only we do have the testing behind us on this system that we did before we launched and landed Curiosity, we have the Curiosity flight itself, and all the telemetry that came back, he said. And it performed extremely well during that mission. Then we did a whole lot of additional testing to launch this spacecraft.

Still, no guarantees, Wallace said. Our hearts will still be beating hard when we get to that point in the mission, but I do think its an advantage that we have. This is not a first-time landing system as we had on Curiosity.

The Perseverance rover will target a landing inside the 28-mile-wide (45-kilometer) Jezero Crater on Mars, home to an ancient river delta and lake that scientists believe filled the crater some 3.5 billion to 3.9 billion years ago. Scientists hope to find signatures of ancient life in the rocks and sediments deposited in the dried-up delta.

Perseverance is designed to land as close to the delta deposits as possible.

To get down onto the crater floor right on top of the delta, we need to do better than weve ever done before, Steltzner said.

Once the rover is on Mars and powers up its science instruments, one of its first tasks will be to place NASAs Ingenuity Mars Helicopter onto the surface. Perseverance will release the rotorcraft from a carrier on its bellyonto the ground, then drive away to a distance of at least 330 feet (100 meters) before the helicopter flies for the first time.

Ground controllers will program the helicopter to perform a series of test flights during a planned 30-day campaign.

The helicopter will fly autonomously, without real-time input from ground controllers millions of miles away. The drone carries two cameras, and telemetry from the helicopter will be routed through a base station on the rover. The Perseverance rover might be able to take pictures of the helicopter in flight.

For the first time ever, were going to fly a helicopter on another planet, Bridenstine said. In the future, it could transform how we do planetary science on other worlds, and eventually it could be a scout so we can figure out where we need to send our robots.

NASA officials approved adding the helicopter to the Mars 2020 mission in 2018.

The atmosphere at the Martian surface is about 1 percent the density of Earths, limiting the performance of a rotorcraft like the Ingenuity helicopter.

The helicopters counter-rotating rotors will spin between 2,400 and 2,900 rpm, about 10 times faster than a helicopter flying in Earths atmosphere. Developed at JPL with assistance from a company named AeroVironment Inc., the Ingenuity rotorcraft is tiny compared to the Perseverance rover. The solar-powered drone measures just 1.6 feet (0.49 meters) tall, weighs about 4 pounds (1.8 kilograms), and has blades spanning about 4 feet (1.2 meters) in diameter.

While the Ingenuity helicopter is purely a technology proof-of-concept, future rotorcraft could be dispatched to other planets with more sophisticated scientific instruments.

NASA has selected a robotic mission named Dragonfly to explore Saturns largest moon Titan. But Titan has a much thicker atmosphere than Mars, which eases the difficulty of rotor-driven flight.

Debuting a wide array of new capabilities, the Mars 2020 mission is packed with firsts.

Were making oxygen on the surface of Mars for the first time, Wallace said. For the first time we have an opportunity to use autonomous systems to avoid hazards as we land in Jezero Crater, and thats technology that will feed forward into future robotic systems and human exploration systems.

Were also carrying microphones for the first time, he said. Were going to hear the sounds of the spacecraft landing on another planet and the rover drilling into rocks and rolling over the surface of Mars. Thats pretty exciting.

For the first time, were going to have an opportunity to see our spacecraft land another planet, Wallace continued. Weve got commercial ruggedized cameras that weve distributed essentially all over the spacecraft, and they will get high-definition video that well bring back after we land on the surface from the entire landing activity from the inflation of the parachute to the touchdown of the rover.

The Mars 2020 missions development cost swelled nearly $360 million over NASAs original prediction, according to the Government Accountability Office. That was caused primarily challenges with perfecting the devices that will collect, seal and store rock specimens, along with difficulties with instruments.

Along the way, we had plenty of challenges, Wallace said. We had to qualify a new planetary parachute. Thats another first the first time weve done that as an agency in 40 or 50 years.

Kind of late in the game, we were asked to accommodate this little thing called Mars Helicopter, he said. It was well after most of the payloads were assigned to the project, so we had to do a little bit of magic trick to get that onto the rover.

Around the time of Curiositys landing on Mars in 2012, engineers at JPL started assessing options for NASAs next major Mars rover. NASA leadership announced plans for the Mars 2020 mission in late 2012, seeking to recycle designs proven with the Curiosity mission also known as Mars Science Laboratory with a different set of scientific instruments, and the new ability to drill core samples, seal them inside ultra-clean tubes, and drop them onto the Red Planet to be picked up years in the future.

We need to make the sample tubes that we take to Mars cleaner than anything that weve ever done before in space, and cleaner than almost everything we do here on Earth, Steltzner said.Part of the effort to do that involves us hyper-cleaning the sample tubes in which the samples that we take on Mars will be placed, and then placing them into the rover at last possible minute.

Read more about the sampling system in our earlier story.

The sample tubes were installed into the Perseverance rover in May, just before it was closed up inside its aeroshell and mounted on top of the Atlas 5 rocket.

Each tube is sheathed in a gold-colored cylindrical enclosure, providing an extra layer of contamination protection. The tubes will ride to Mars inside the housing, and they will be returned to the sheath once filled with Martian rock samples.

The Perseverance rover will carry 43 sample tubes to Mars, including witness tubes or blanks, which will allow scientists to cross-check rock and sediment specimens returned to Earth for contamination.

The tubes are about the size and shape of a slim cigar, and the Perseverance rover will collect core samples on Mars that measure around a half-inch (13 millimeters) wide and 2.4 inches (60 millimeters) long.

Those samples tubes are part of a Sample and Caching System, which is one of our biggest engineering developments for this mission, Steltzner said. We get to Mars largely like the Curiosity rover got to Mars, but we need to do something very different once were on Mars. We must take these core samples, seal them hermetically and sterilely, and then produce a cache of samples for eventual return to Earth.

The Sample Caching System is a complicated piece of equipment, with 17 separate motors, a rotating wheel containing nine drill bits, and 43 tubes to hermetically seal core samples drilled from Martian rocks.

The rover has a 7-foot-long (2-meter) robotic arm with a coring drill fixed on a 99-pound (45-kilogram) turret on the end. The longer robotic arm will work in concert with a smaller 1.6-foot-long (0.5-meter) robotic manipulator inside the belly of the rover, which will pick up sample tubes for transfer to the main arm for drilling.

Steltzner said the rovers sampling system actually consists of three different robots.

Out at the end of our robotic arm thats the first robot is a coring drill that uses rotary percussive action like we have used similarly and previously on Mars with the Curiosity mission, except rather just generating powder, this creates an annular groove in the rock and breaks off a core sample, Steltzner said.

During each sample collection, the core sample will go directly into the tube attached to the drill.

That bit and the sample tube are brought back by the robotic arm our first robot into the second robot, our bit carousel, which receives the filled sample tube and delivers it to a very fine and detailed robot, the sample handling arm inside the belly of the beast, in which the sample is then assessed, its volume is measured, images are taken, and it is sealed and placed back into storage for eventually being placed in a cache on the surface.

The portion of the caching system inside the rover is called the Adaptive Caching Assembly, which consists of more than 3,000 parts alone.

The design of the drill and sample tubes is intended to preserve the distribution minerals cored from Martian rocks. The system is also intended to collect samples directly from softer soils.

NASA selected seven scientific payloads to ride to Mars on the Perseverance rover in 2014.

Two of the instruments, named PIXL and SHERLOC, are located alongside the coring drill on the robotic arms turret. Theywill scan Martian rocks to determine their chemical composition and search for organic materials, providing key inputs into decisions by ground teams on which rocks to drill.

The Mars 2020 rover also carries the SuperCam instrument,an intricate suite of sensors, including a camera, laser and spectrometers, designed to zap Martian rocks from more than 20 feet (6 meters) away to measure their chemical and mineral make-up, with the ability to identify organic molecules.

Developed by an international team in the United States, France and Spain, the SuperCam instrument is an upgraded version of the ChemCam instrument currently operating on NASAs Curiosity Mars rover.

The instruments mounted inside the Mars 2020 rovers main body include MOXIE, whichwill demonstrate the production of oxygen from carbon dioxide in the atmosphere of Mars, a capability that future astronaut explorers could use on the Red Planet. A Norwegian-developed ground-penetrating radar on the rover named RIMFAX will study the planets underground geologic structure, yielding data on subsurface layers and soil strength which could help designers of larger landers designed to carry people to Mars.

The mission also carries a weather station and 23 cameras the most ever flown on a deep space mission including the first camera on Mars with a zoom function. That camera system, located on top of a mast Perseverance will raise after landing, is named Mastcam-Z and will record video and 360-degree panoramas.

Were carrying about 50 percent more surface payload than Curiosity did, and that was, by far, the most complex thing weve ever done up to that point in time, Wallace said. Were taking this a step further.

The differences between Perseverance and NASAs predecessor Curiosity rover do not stop at the science payload or the Ingenuity helicopter.

The Perseverance roveralso features aluminum wheels with thicker skin and modified treads to avoid damage observed on Curiositys wheels on Mars.NASAs new Mars rover weighs about 278 pounds (126 kilograms) more than Curiosity.

The benefit of another decade of technological advancement since Curiositys launch, and the budding fruits of NASAs partnership with ESA on a Mars Sample Return program, moves scientists closer to addressing the question of whether life took hold elsewhere in the solar system, Bridenstine said.

We are, in fact, trying to find signatures of life, and of course, were interested in finding life itself, Bridenstine said.

While NASA officials are careful to say Perseverance is not a mission to detect life, its launch and landing on Mars will be a big leap forward in the search.

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NASA's Perseverance rover signals new era in Mars exploration - Spaceflight Now