Mars is a mystifying, complex and challenging world to investigate. It has been a magnet for our curiosity throughout the decades; robotic craft sent there have attempted to purge that faraway globe of its stealthy truths. In particular, has that planet in the past — or is now — an extraterrestrial address for life?
Safely landing on Mars is one thing. Surviving and flourishing there is another. Once humans are firmly footed on Mars, just staying alive on that distant destination will be a daunting task.
SpaceNews brought together a trio of Mars exploration experts to discuss the upcoming launch of NASA’s Mars 2020 Perseverance rover, the ongoing search for past and present evidence of life on the Red Planet, and future exploration of that far-off world.
Here are some key takeaways from our June 24 webinar.
ON PERSEVERANCE
NASA’s Perseverance Mars rover will search for signs of past life on the Red Planet. The wheeled robot is targeted to land within Jezero crater, an area thought to have once been flooded with water. The crater’s ancient lakeshore may have preserved fossilized microbial life, if any ever formed on Mars. In addition, the robot will unleash a drone-like helicopter that will attempt powered flight in the Martian atmosphere. Also being carried by the rover is an oxygen generator designed to convert the planet’s carbon dioxide-laden atmosphere into breathable oxygen.
What are the objectives of this new NASA Mars rover?
Kenneth Farley, Mars Perseverance mission scientist: This is essentially a mission with three goals: astrobiology, Mars sample return and enabling the future by testing new technology. This is a very exciting moment. The spacecraft is essentially done from the JPL perspective. We’ve got a few more things that have to happen, but all is in good shape for that.
The Mars 2020 mission is conceived as the first step in a series of missions that could bring samples back to Earth and, in particular, Mars 2020 is tasked with collecting the scientifically selected samples. We will collect about 35 samples that each weigh about 15 grams. Picture a cylinder of rock cores from the planet’s surface … about the size and shape of a piece of chalkboard chalk. So we will collect those from a variety of locations around the landing site.
And just how important are those samples to inspect back here on Earth?
Farley: I see a big diversity of scientific questions that really require us to have samples in terrestrial laboratories. One of the really key questions that is almost impossible to answer with spaceborne instrumentation is the definitive documentation of life beyond Earth. That has such a huge burden of proof. We don’t really expect to be able to do that with instruments that are presently flyable.
James Watzin, Mars Exploration Program director: This mission has gotten doubly exciting because it is the first leg of Mars sample return. We have been working really hard over the last several years with ESA to develop a partnership, to share the burden of the remaining two missions that it takes to bring home the samples … and are now working toward a goal of being ready to launch [the sample return campaign] in 2026 and bring the samples back to Earth in 2031. In the big picture, this is humanity’s first round-trip to another planet, and it begins with Mars 2020.
ON LIFE DETECTION
NASA’s dual Viking Mars landers that touched down on the planet in 1976 were bold approaches to asking a key question: Is there life on Mars? Biology experiments carried by each of the spacecraft revealed unexpected and enigmatic chemical activity in the Martian soil. However, no clear evidence was found for the presence of living microorganisms in Martian soil near the landing sites — although one Viking experimenter claims to this day his experiment did discover living microorganisms on the Red Planet. The investigation got positive responses at both Viking landing sites, he claims. However, a consensus did not accept his results as proof of life.
Searching for life on Mars has been a long-slog saga. Are we asking the right questions with the right instruments?
Farley: As far as we know, there is nowhere on the surface of Mars, and I’m being very careful to say on the surface, that is habitable by any known terrestrial organism. So the idea that there might be life on the surface readily accessible, which was the Viking concept, that is not widely believed to be possible. So in thinking about how we might investigate for life … it’s very clear from the geologic setting on Mars, that it was once very different. Right now, it’s too cold, too dry, and too much radiation on the surface for any life as we know it. But if you look at the planet, about three and a half billion years ago, there were lakes and rivers. So what’s different is we’re going to look at a different time. We could fly lots of instruments. But we don’t know what we’re looking for. If you’re looking at ancient rocks, what exactly should you look for [in terms of] life that might be different from terrestrial life? I think it’s a very tall order. But it is something that is the natural thing you would do if you brought samples back … and not trying to do this with flown instruments alone.
Since Viking, how has NASA’s strategy changed?
Watzin: The Mars program strategy set out over the last 15-20 years, we wanted to be very methodical in the search for life. Viking was hoping they’d find something that would be prevalent on the surface and they would be able to detect life. We’ve since learned the surface is actually quite a hostile environment. So we stood back, becoming a bit methodical about how we investigate the possibility of life. We need to better understand the evolution of the planet and determine whether it was ever habitable. And if it was habitable, where was it habitable? Both with orbiter reconnaissance and then the rovers, we have a [Mars 2020] landing site that was clearly habitable. We’ve been trying to identify and follow the path of the highest probability with a sequential increase in our capabilities. The Perseverance rover is the next big step.
ON HUMANS TO MARS
There is an extensive search underway for locations on Mars that will eventually be dotted by human boot prints. Such locales need to be of high scientific research payoff. But they also require the natural resources to enable human explorers to land, live and work sustainably and safely on the Red Planet.
In October 2015, NASA held a seminal meeting that brought together top experts on Mars to kick-start the selection of the first human landing sites. The result of the workshop was picking nearly 50 “Exploration Zones” on Mars — places where crews can explore far away from their habitat.
Given that meeting and follow-on work, where is NASA on selection of the first spot on Mars for humans to touch down? What issues demand more study?
Rick Davis, NASA’s assistant director for science and exploration: That workshop was eye-opening. The major focus was on better understanding of water feedstocks on Mars. We realized that it’s water, water, water. Fortunately, Mars has lots of water. There are buried deposits of water, probably oceans and glaciers there. We need to know exactly where they are and how close to the equator they come because it’s warmer there. Eventually, we need another Mars orbiter with a radar that has the right frequencies for the ice story that we now know exists. We need to nail down where those deposits are. Also, we need to dramatically increase our high-resolution imaging of the planet. We have only about four-percent of the planet in high-resolution imagery.
Over time we have gotten a lot smarter about other things we need to know about the planet to enable human spaceflight to Mars. For one, we really need to understand how dust can impact the crew, their spacesuits and the equipment supporting the crew. Also, we do not want to be landing in major dust storms. That’s bad news. We probably need to understand density profiles better to handle large human-class landers.
Finally, one of the big reasons you go to Mars is to search for life. We do not want to be mixing the human biology that human beings will be taking with them as they explore our second planet. So understanding how biological releases transport in the Martian atmosphere with winds is key.
ON INFRASTRUCTURE UPGRADES
What other infrastructure may be required to support human explorers on Mars?
Davis: Right now, communications at Mars is relayed through orbiters that are in low Mars orbit. So that we can pump data up from the surface all the time, putting in a small constellation of say three satellites in an equatorial orbit, you can achieve a dramatic improvement in the total communications capability at Mars. The amount of data and science you can relay back to Earth goes up almost two orders of magnitude.
ON LOOKING FOR LIFE ELSEWHERE
Given the experiences at Mars to look for life, is there a message to those searching for life at outer planet distances, such as at Jupiter’s Europa or Saturn’s Enceladus?
Watzin: It is certainly not a hunt and peck activity. So I think what we learned at Mars has come out of the long, systematic approaches and continuity between the missions … the focus to understand the environment, its evolution, its current condition. All those things and how they tie together. Exploration for life at Mars, or anywhere, is a long, hard slog. But it’s extremely stimulating and interesting. It promotes the advancement of technology, as well as science, and an understanding of our place in the universe. So patience, I think, is probably the biggest word that has to be attached to it. No one mission is going to satisfy our curiosity.
WEBINAR REPLAY
To watch a video replay of our panel discussion on Mars exploration, go to: https://spacenews.com/webinar-mars-exploration-blueprint-for-the-red-planet/
This article originally appeared in the July 13, 2020 issue of SpaceNews magazine.
