A hot debate about how best to advance Mars exploration has been going on this week in the cold northern town of Lulea, Sweden. Scientists from many international space agencies and research organizations attended, including NASA, ESA, the Chinese and Japanese space agencies, and even the United Arab Emirates, which plans its own Martian mission for 2021.
The discussion has focused on several themes, including what geographic features and landing sites we should concentrate on when investigating Mars. Should we continue to look for evidence of water-related features, as suggested by Usui Tomohiro from the Japanese Space Agency? Or should we be more aggressively hunting for organic molecules (which have already been found), or even searching directly for life?
The discussion of which approach is best was led by Monica Grady from Open University in the U.K. and me. The next approved missions are NASA’s Mars 2020, which will collect samples for later return to Earth, and Europe’s ExoMars 2020, which includes a rover and a Russian-built surface platform. Grady made the case that sample return is the right focus for the NASA mission and wondered whether any significant results can be obtained with further robotic exploration similar to the current Curiosity mission.
As co-chair of the same session, I disagreed, arguing that a life detection mission should be conducted before a sample return mission, in part because putting a sample in a box would reduce or completely erase any biological or chemical signal during transport. In addition, no retrieval sample facility has been built yet on Earth, nor has a biohazard test plan been developed to handle extraterrestrial samples, even though there is agreement that such a facility is essential. I also contended that the technology is now ready for a life detection mission to Mars. Even though there does not yet exist a single method for unambiguously detecting past or present life, it can be done using multiple, complementary new techniques. However, what would be needed as preparation is a facility for sterilizing spacecraft. Such a facility, in essence a giant “baking oven,” was used to heat-sterilize the Viking landers before launch in the 1970s, but we don’t have such a facility anymore.
The point was made during the discussion that the U.S. Congress has already approved a Mars sample return, and that changing the priority to life detection would delay Mars exploration. A compromise might be to combine the two approaches, and analyze any collected Martian samples for microorganisms before they are placed in a sample return container for return to Earth. This would ensure the maximum scientific return, but will also make the mission more complex and expensive.
In another talk, Gerhard Kminek from ESA and Cassie Conley from NASA discussed planetary protection policies. They pointed out that these may change, considering that human missions to Mars may happen as soon as the 2030s. An earlier life detection mission would likely go into the so-called Special Regions on Mars, where life might exist, and which would significantly increase the cost of such a mission due to required sterilization measures.
Two final themes were tackled by Maria-Paz Zorzano and Javier Martin-Torres, both from Lulea University of Technology in Sweden. Zorzano talked about Mars exploration by private space companies, as opposed to government agencies, and considered how to coordinate the activities of this larger “Mars exploration family.” This struck me as a bit naïve. The landing of humans on the Moon 50 years ago was based on competition between the Americans and the Soviets, and given the current climate of nationalism and populism, it’s difficult to imagine that we can pull off such a major achievement based on cooperation only. Kumbaya is great, but it does not seem to work for space exploration.
Martin-Torres addressed whether the Moon should act as a gateway to Mars, or whether this would delay Martian exploration. Advantages of a lunar steppingstone would be the Moon’s proximity and its low gravity, making it easier to reach and lift off into space. However, the Moon also has challenges, including extreme temperature variations and radiation. It’s not a friendly place at all for astronauts. The audience had no clear preference on this topic. One thing they agreed on, though—the exploration of Mars should move forward.
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