Daily Archives: April 21, 2017

Plans by private space explorers to launch "mega constellations" of thousands of communications satellites to allow for global wireless services could lead to a rise in collisions and buildup of dangerous space junk in Earth's orbit, a study has warned, suggesting corporate interest in space is perhaps somewhat sky high.

A variety of companies, including Google, SpaceX, Boeing and Samsung, are vying to launch global broadband networks via the deployment of thousands of micro satellites into low orbit. The first launches are planned for 2018.

However, a team of Southampton University researchers, led by Dr. Hugh Lewis, senior lecturer in aerospace engineering, have concluded the results could well be calamitous. The group ran a 200-year simulation to assess possible consequences of such a rise in orbital traffic, concluding it could create a 50 percent increase in the number of catastrophic satellite collisions.

Such crashes would likely produce a further increase in the amount of space junk orbiting the Earth, raising the prospect of further collisions and potential damage to the services the satellites were intended to provide.

"The constellations that are due to be deployed from next year contain an unprecedented number of satellites, and a constellation launched without much thought will see a significant impact on the space environment because of the increased rate of collisions that might occur," Dr. Lewis said.

With approximately 750,000 objects larger than one centimeter orbiting Earth, junk surrounding the planet is already a major obstacle to attempts to explore space. At average speeds of 40,000 kilometers per hour, impacts on space hardware would deliver roughly the energy equivalent to the explosion of a hand grenade, with potentially dramatic consequences for operational satellites.

The team's research was funded by the European Space Agency, which is now calling for all satellites planned for orbital mega-constellations to be able to move to low altitudes once their missions are over, so they burn up in Earth's atmosphere. The ESA state they should also be able discharge all batteries, fuel tanks and pressure tanks to prevent explosions that would scatter debris.

Dr. Holger Krag, head of the Agency's space debris office, said many companies proposing to launch services provided by such mega constellations lacked experience of the difficulties of working in Earth's orbit.

Moreover, Dr. Krag expressed concern at ambitions to manufacture satellites at a fraction of the cost and many times the rate of traditional taxpayer-funded spacecraft, while still meeting exacting guidelines for their post-mission disposal.

"Right now, under all the taxpayer-funded space flight we are doing today is only able to achieve 60 percent of success rate for that maneuver. How can they be better under commercial pressure and with cheaper satellites? That's the worry we have," he said.

Dr. Lewis is to present his research at the ESA center in Darmsadt, Germany, where some of the aspirant private space explorers will also be in attendance.

"Even with good intentions it remains an extremely high technological challenge to manage to [meet ESA proposals]. Let them achieve a success rate of 90 percent, which would be extremely good compared with what we do now, and it still means a few hundred satellites will be lost and at that altitude it's not good. It's as simple as that," Dr. Krag concluded.

Exacerbating the situation, Dr. Lewis believes, is a lack of a dedicated international body dealing with the issue of space junk.

"Junk is dangerous. While some will de-orbit naturally after 5-10 years, some will drift indefinitely. Disposal isn't easy either - even to get a ship into orbit is very costly, and then there's the issue of securing the junk in space before you can even consider getting rid of it," Dr. Lewis told Sputnik.

However, he adds that research into these issues is significant and ongoing - the end result could be spacecraft equipped with retrieval solutions similar to those seen in science fiction movies. Another option is "in-orbit" servicing, which would mean satellites could be upgraded and repaired in space - meaning few if any satellites will be reduced to junk status.

"In-orbit servicing is the next big thing. However, there are a number of challenges to achieving that goal - and another issue is upgrading old satellites that aren't equipped for updates. It's difficult to interact with an object that is not prepared for it. We need to ensure in our quest to clean up the junk that we don't add more and make the problem worse."

Source: Sputnik News

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Waste Cadets: space plans mean more space junk, harder space exploration - Space Daily

In their own way, Musk and Glenn each represent the hopes and dreams of those who delight in the idea of mankind leaving the bounds of Earth and exploring the solar system and, ultimately, the stars.

Over the past 50 years, we've seen men first orbit the globe and then walk on the moon. We were gripped b the fictional journeys of the Starship Enterprise, which explored the galaxy, encountering new life and new civilizations. Popcorn in hand, we watched Matt Damon struggle to survive in "The Martian."

We have dreamed of a time when humans can travel through space as readily as when early mariners unfurled their sails and headed west in search of new lands. But we might not have stopped and asked an important question.

Now, I am not asking whether we should explore the universe. I also dream of the day that we become galactic citizens. The question is whether the initial exploration of space should be done by humans or by robots. I would argue that, for the moment, robotic exploration should have the upper hand.

Proponents of the astronaut-preferred camp point, quite rightfully, at the versatility and independence of humans. Fans of human spaceflight are certainly correct when they remind us that humans are highly versatile. People observe the conditions around them and can react to circumstances as needed.

However, people are also fragile. They need food, water, and air. They can exist in only a narrow range of temperatures and find inhospitable both vacuums and a radioactive environment. While some adventurers might prefer to remain in space forever, many of them expect to land gently back on Earth. All of these considerations are extremely challenging and not important for robotic missions.

Possible manned missions to Mars are imagined to cost about $1 trillion, with the outcome being limited exploration of the Red Planet by about 2030 (with some estimates saying 2050). And a mission with that price tag would hamstring the rest of the space program.

In contrast, robotic exploration of the solar system is far less costly. The Cassini mission to Saturn cost about $3.2 billion. The Mars Curiosity Rover cost about $2.5 billion. These and other missions have been wildly successful in teaching us about places where literally no one has gone before. Mars missions have explored ancient streams where knee-deep water once flowed and have found organic carbon embedded in surface rocks.

In addition, there are methods for exploring the cosmos that don't require actually going to the place under study. The Hubble telescope, has perhaps revealed more about the universe than any other scientific instrument, cost about $14 billion, including imaging the first galaxies formed and played a key role in the discovery that the expansion of the universe is accelerating. And the wildly successful planet-hunting Kepler satellite weighs in at under $1 billion.

Manned programs can cost tens or hundreds of times more than the robotic missions.

But it's not just about the money. There are three important goals we need to achieve from our space program. The first is monitoring our own world, resulting in storm warnings and help in understanding our complex planet, which can best be done by tireless satellites orbiting the Earth. The second is to learn more about our solar system and the more distant universe. On this, the case is also clear: robotic exploration, through either space probes or telescopes, provides a much better yield for much lower money.

The final goal is that of making humanity a multiplanetary species. By definition, this includes manned spaceflight, but the question is really how we should achieve that objective.

Developing human space-faring technology is crucial, but first we need to decide where to go. The moon is a dead planet and Mars is not nearly as welcoming as the New World was to the Spanish explorers. In fact, there is no place in our solar system where pioneers can simply drop seeds in the soil and wait for food to pop out of the ground. For that, we need to look at distant stars.

And interstellar exploration is also something in which robots will lead the way. Following the identification of a possibly habitable planet by the Kepler satellite or perhaps PLATO, a European Space Agency planet-hunting telescope scheduled to be launched in 2024, the next step would be a survey of the planetary system by an unmanned probe.

And if we chose to explore the nearest sun-like star, the signal transit time is more like 24 years. With a multiyear time lag between messages, the interstellar probe will have to be able to execute independent judgment.

Only once a habitable planet is identified by these robotic approaches, will it be the time for a manned mission. With a welcoming destination beckoning to them, a team of intrepid men and women will leave the solar system and strike out for a new home. And, at that moment, homo interstellaris will come of age.

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Machines, not people, should be exploring the stars for now - CNN

The future of space exploration and technology is a hot topic these days, fueling blockbuster movies and heightening attention about travel to Mars and other planets one day.

On Friday and Saturday, the University of Massachusetts Lowell is convening scientists, former astronauts, and industry leaders for two days of talks on the topic. The symposium Space Exploration in the Upcoming Decade: The Domestication of Space is presented by the colleges Center for Space, Science, and Technology.

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Much has changed since the center held an event 10 years ago to mark the 50-year anniversary of the start of the Space Age, a period begun by the famous 1957 launch of the Soviet satellite Sputnik, said the centers director, Supriya Chakrabarti.

When we first met 10 years ago, we didnt predict how accessible space would become, Chakrabarti said. The rise of private companies like SpaceX, Blue Origin, and others operating in space and taking people up into space, its a big change.

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These talks and panels are going to touch on the way space has changed and the new areas that have opened up, he said.

Speakers include: James Abrahamson, former designated astronaut and former associate director of NASA; Robert Cabana, former astronaut and current director of the Kennedy Space Center; and John Connolly, leader of NASAs Mars Study Capability Team.

The subject of sending humans to Mars is topical, as nations and private companies explore the possibility of missions, Chakrabarti said. The United Arab Emirates is planning to launch a satellite in 2020 and SpaceX founder and CEO Elon Musk is asking for volunteers for a potential one-way trip.

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Getting someone to Mars is feasible, Chakrabarti said. Its the getting them back that poses much of the problem.

To get to Mars, there are two main things to keep in mind the launching and the landing. To get someone back, you need to do even more planning and pack the required fuel, he said.

In spite of all the challenges that face humanity in space, Chakrabarti said, he remains hopeful that a bright future awaits.

Were doing things that we couldnt have even imagined 10 years ago, he said. The tools are so much more sophisticated and my students are so good at using them. Theyre so passionate.

I was 4 when Sputnik launched and now Ive built instruments that are now on the International Space Station, he added. Its great fun.

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UMass Lowell looks ahead to our future in space - The Boston Globe