If there is liquid water on Mars, no one—not even NASA—can get anywhere near it
by Akshat Rathi / September 29, 2015
“NASA claims to have found evidence of liquid water on Mars. If true, you’d expect the US government to scramble to set up a new mission to test the claim. After all, discovering that Mars has life or even that in can support life will be one of the greatest discoveries ever. But that won’t happen so quick. NASA’s press statement makes it seem that scientists have certain evidence of flowing water. They do not. What they have is chemical evidence that gives a strong suggestion of liquid water mixed with salts. More importantly, however, even if NASA was 100% certain that there is liquid water on Mars, it could not do anything about it. The world’s space powers are bound by rules agreed to under the 1967 Outer Space Treaty that forbid anyone from sending a mission, robot or human, close to a water source in the fear of contaminating it with life from Earth.
Terrestrial life has been shown to be very resilient. Microbes are found in almost every nook and cranny of this planet, even the driest and hottest parts. Earth’s microbes survived nearly two years stuck on the outside of the International Space Station. All probes that land on Mars are cleaned to be sterilized of life but no one yet knows how strict you need to be to ensure that bacterial life cannot form viable, self-sustaining colonies on Mars. All space missions to an alien world are bound by planetary protection protocols. On Mars, these protocols determine which areas a mission can and cannot land, and how far it can explore after landing. And the more we learn about Mars, as a 2014 report makes it clear, the more special regions are being found where we can’t send missions.
Areas that are warm or wet enough to support Martian life are out of bounds. Polar ice caps, caves, and regions with volcanic activity are such special regions. Even regions where ice is found as deep as five meters below the surface are on the list. And even that won’t cover all eventualities. The Mars 2020 Rover, for instance, carries a plutonium-powered heat generator, which can, if it falls on the surface, cause ice deep inside to melt and create liquid water. Its exploration area, then, is further restricted. The irony is that all these restrictions mean NASA has to stay away from the very regions where it may find water or Martian life. NASA’s hype around the discovery of liquid water on Mars can be explained by its constant need to increase funding for its work. And that attention seems to be helping. But it won’t be eager to tell you that its human mission, currently planned for 2030, will inevitably contaminate Mars with microbes, and break the rules of an international treaty. Indeed, what’s the guarantee that all those objects and rovers we’ve sent to Mars haven’t already contaminated the red planet?”
An animation showing markings from water flowing across the surface of Mars (NASA)
NASA’s Mars rovers can’t explore wet Martian sites for fear of contaminating them
by Marcus Strom / September 29, 2015
“NASA has a Mars explorer about 50 kilometres from a site that shows promise it holds Martian water, but the US space agency can’t send the rover there to find out. Why not? The rover, which has travelled 225 million kilometres from Earth to get there, is not sterile enough. In a revealing response during an “ask me anything” session on website Reddit, NASA’s chief scientist for its Mars program, Rich Zurek, said: “Because liquid water appears to be present … we have to take extra precautions to prevent contamination by Earth life. Our current rovers have not been sterilised to the degree needed to go to an area where liquid water may be present.”
“All of our spacecraft carry microbes from Earth,” Swinburne University astronomer, Alan Duffy, told Fairfax Media. “We try our best to sterilise them by putting them in an ultraviolet tanning salon – but a very intense one.” When preparing spacecraft for Mars missions, scientists have to get the balance right between this sterilisation and protecting the delicate electronics on board. “In order to be completely sterile, they’d have to use really powerful ionising radiation or heat, both of which would damage the electronics,” UNSW astrobiologist Malcolm Walter told Fairfax Media. “So they go as far as they dare.”
On Tuesday NASA announced that dark, narrow gullies on the Martian surface contain water-bearing salts that formed from flowing water flowing during warmer periods. While it wasn’t part of the study published in Nature Geoscience on Tuesday, very similar slope activity has been identified about 50 kilometres from the Mars Curiosity rover. Dr Zurek said: “There are no confirmed brine flows (RSL) near Curiosity nor Opportunity [rovers]. There are in Gale crater some interesting slope streaks but they are several km away from the Curiosity’s present path.” The Curiosity rover has been exploring the Gale crater on Mars since it landed three years ago.
Dr Zurek’s revelation that the Mars Curiosity rover might be contaminated with Earth-origin microbes caused a flurry of questions on the Reddit AMA. “If the rovers haven’t been properly sterilised already, will this throw doubt upon any possible future discovery of Mars-based microbes? Wouldn’t detractors be able to claim that they are microbes that somehow survived from Earth?” asked one participant. Dr Zurek’s response should satisfy most, except the most ardent conspiracy theorists: “The rovers have been sterilised for their particular landing sites where there’s been no evidence of present day liquid water. To go to the RSL [sites] rovers will be required to be sterilised to a higher level. We also take samples of microbes that might be on the spacecraft before they’re launched, so we can compare with any future discoveries.”
Planetary scientists detected hydrated salts on these slopes at Horowitz crater, corroborating their original hypothesis that the streaks are indeed formed by liquid water. Photo by NASA/JPL/University of Arizona
Two other problems mean Curiosity can’t go taste the water to test for life. The slopes are too steep and, anyway, there are no DNA sequencers on board. “These features are on steep slopes, so our present rovers would not be able to climb up to them,” Dr Zurek told Reddit. He also said: “The Curiosity rover does not have life-detection instruments.” The next generation of NASA’s Mars rovers are due to be sent to the red planet in 2020. New Scientist reported that some astrobiologists have criticised NASA for not including DNA sequencers and other life-detecting instruments in its plans for these planetary explorers. Professor Malcolm Walter is the founding director of the Australian Centre of Astrobiology at the University of NSW. He told Fairfax Media that it’s too late to modify the 2020 missions to take into account Tuesday’s announcement. But he said of the discovered water locations: “They’d have to be high-priority sites now.” The European Space Agency’s ExoMars mission in 2018 will launch a Mars rover with an organic molecule analyser to continue the hunt for life on Mars.”
NATIVE MARTIAN GENETICS
NASA urged to seek live Martians with 2020 rover
by Lisa Grossman / 13 July 2013
“Genome sequencers and other devices that could reveal whether anything is alive on Mars right now should be ready to launch with NASA’s next Mars rover in 2020. The trouble is, the rover team may not want them – and some astrobiologists are crying foul. Earlier this week NASA announced its science goals for the next US rover headed for the Red Planet, known for now as Mars 2020. Essentially a duplicate of the Curiosity rover now on Mars, this robot has been tasked with searching for evidence of past life and collecting rock samples for eventual return to Earth. Sample-return has been at the top of the Mars community’s wish list for decades. The caching component of Mars 2020 represents a revival of a well-studied plan to bring Martian rocks back to Earth for detailed study. But others think the rover’s approach to life detection is overly cautious. The Mars 2020 will primarily search for signs that something lived on Mars in ancient times, even though the technology exists to hunt for alien microbes presently living on or just beneath the surface. “It is the same old depressing story of NASA vetoing any proposal to do biological experiments on Mars,” says Paul Davies of Arizona State University (ASU) in Tempe. “I personally think this is absurd.”
One potential life-seeking experiment is the Search for Extraterrestrial Genomes (SETG) project, based at the Massachusetts Institute of Technology. Previous experiments for detecting existing life on Mars, such as the one on the 1976 Viking missions, focused on finding organic carbon, which is necessary for life as we know it but can also be produced by non-biological processes. Viking scientists initially reported such hints of life on Mars, but the results were ultimately deemed inconclusive. “We went and looked for life on Mars with Viking, and since then we’ve been in the mode of looking for past life,” says Chris Carr of the SETG project. “That’s made sense. We didn’t want to repeat Viking, where we couldn’t make sense of the results.”
Finding DNA or RNA would be a much less ambiguous signal of life, past or present. A gene sequencer could even figure out whether that life is related to Earth life, or if it had a unique origin. Doing DNA analysis on Mars rather than waiting for the Mars 2020 samples to come home also means you can be confident that the samples have not degraded in transit. “Sample-return is an important mission and we should do it, but I don’t think we should wait until we have all parts of that mission to look for extant life on Mars,” says Carr. His team is developing a robust sequencer small enough to fit on a rover, and they are already field-testing prototypes. “I think we could produce something in time for the Mars 2020 mission,” he says.
An even simpler experiment would create habitable hot spots on Mars. Dirk Schulze-Makuch of Washington State University and colleagues argue that if microbes are currently present on Mars, they may be lying dormant to survive the planet’s extreme dryness and cold. If you could warm them up, protect them from radiation and give them a refreshing drink, they might bloom. Their project, outlined in a paper published this week in the journal Astrobiology, is called Detection of Mars Extant life in the near-Subsurface (DOMES). A rover would scratch out a trench to expose the Martian subsurface and put down a clear plastic cup containing water and organic compounds, inverted like a tiny biodome. Similar schemes have encouraged lichen and moss to flourish in the otherwise sparsely populated sands of the Namib Desert.
Gil Levin of ASU, who led Viking’s life-detection efforts, still hopes to see that experiment vindicated. “NASA says the greatest question confronting us is, are we alone?” says Levin. “Thirty-seven years ago, they got at least an ambiguous response. What do you do with an ambiguous response? You settle it. You don’t run away from it.” Together with Davies and Ariel Anbar, also of ASU, Levin is currently developing a capsule that would carry multiple small, dart-like instruments, which could shoot away from a rover or lander, plunge down into the soil and repeat the Viking experiment several times with different controls. “That would not only verify that we had detected life previously or disprove it, but would also begin an investigation of what kind of life that is,” he says.
NASA is throwing open the door for proposed instruments to fly on Mars 2020, so while these experiments may go beyond the rover’s stated goal, they can still compete for a spot. And if they are not selected for this launch, the sample-return effort may give them another shot. The most likely strategy for returning samples stored on the 2020 rover will involve two more spacecraft heading to Mars, says Charles Whetsel of NASA’s Jet Propulsion Laboratory in Pasadena, California. Another rover will need to pick up the cache and loft it into orbit, and an orbiter or flyby mission will have to pick it up. Both of those missions would offer opportunities for new science experiments that could search for extant life, either carried on the pickup rover or dropped by the orbiter. In the meantime, Whetsel defends the decision to hold off on searching for existing life right now. “It’s probably easier to prove there was once life on Mars than to prove it survived and it exists today,” he says. “It would definitely be front-page news if we determined there is currently life on Mars. I think it’s equally front-page to say there was once life on Mars.”
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