A subcommittee of the Senate asked for reasons to send people to Mars, and, boy, they got one from Ellen Stofan, the former NASA chief scientist.
Stofan, who now heads the Smithsonian National Air and Space Museum, argued that if we really want to find and understand all possible traces of the old life on the Red Planet, robots can not do it alone – we have people on the ground required .
"Although I am optimistic that life on Mars has evolved, I am not optimistic that it has become very complex, so we are talking about finding fossil microbes," Stofan told a subcommittee of the Senate on 1 September with scientific issues. that those fossils would be incredibly hard to find. [The Search for Life on Mars (A Photo Timeline)]
"That's why I think it needs people on the planet, who break open a lot of stones to try and find this evidence from the previous life," said Stofan. "And finding an example is not good enough, you need multiple examples to understand the diversity."
NASA has not sent a robot to identify traces of life on Mars since the Viking missions in the 1970s. But is there the fastest possible human Mars mission that is still ten years and a half away, hope that robots could establish the old Marlies life before the people arrive?
Whether our emissaries that live on the hunt are mechanical or human, they will be guided by what we have learned on earth – and discovering the old microbial life is already quite difficult here, Frances Westall, an astrobiologist at the National Center for Scientific Research in France, Space.com told. Westall, who is looking for traces of the old microbial life on earth, said: "That is still quite controversial and that has access to the most advanced laboratories on earth." At the moment, she said, work is always based on a combination of people on location and distant laboratories – not robots.
Just like here on earth, scientists are fighting a number of grim opportunities when it comes to hunting for traces of Mars organisms that lived billions of years ago. "Of course most things will never fossilize: a few things are saved, mostly those that have hard parts," Sean McMahon, an astrobiologist at the University of Edinburgh in the UK, told Space.com.
But on the one hand, the search for the old life on Mars has a leg above its earthly equivalent, since Mars has no phenomena such as plate tectonics and volcanism that constantly destroys its geological reputation, told Tanja Bosak, a geobiologist at the Massachusetts Institute of Technology, Space.com. So if there were lives billions of years ago on the Red Planet, its traces could continue to exist.
Robots versus people
Mars has attracted successful landers and robbers in the course of the eighties, of which the most prominent current inhabitant is NASA's Curiosity Rover. That mission was carefully designed to look for places where life could have ever flourished – but not to seek traces of that life.
And it has done exactly that, identifying mud stones in Gale Crater as particularly promising and spotting old organic molecules that have not necessarily been created by life. But robots are not perfect, and there are still enough persistent questions about the geology of Mars, he added. "There are rocks that robbers have visited and mapped and analyzed and we are still arguing about what they are," McMahon said. [Ancient Mars Lakes & Laser Blasts: Curiosity Rover’s 10 Biggest Moments in 1st 5 Years]
But robots are much harder than people. "The place where I would start the conversation is where it is safe to land, and the robot program has a proven ability to land on difficult terrain," says Ken Farley, an astrobiologist at the California Institute of Technology and the principal investigator. from NASA's next Mars rover, Space.com told, adding that robots can land closer to the rocks that scientists want to watch. While people are more mobile than robots, Neil Armstrong and Buzz Aldrin covered only about 90 yards (82 meters) during their lunar landing.
Because Mars's life has probably never become larger than microbial, the functions scientists are looking for will fit into the perspective of a robot. But there are some ways in which people still surpass robots, especially when it comes to looking at the larger picture of life on Mars. "Biologists, geologists and chemists on the ground could do more than identify evidence of previous life on Mars," said Stofan to the senators. "They could study the variation, complexity and relation to life on Earth much more effectively than our robotic emissaries."
And Westall said she does not think robots will ever match human geologists because of their knowledge and instincts in the field, or their productivity. "I am a geologist and I go into the field and I have to see things with my eyes, and if I had the chance to go to Mars," she said. "A human geologist can do in a week what the March wanderers can do in a year."
Best of both worlds?
But there is a kind of compromise that may be even more productive than the landing of people on Mars. The secret lies in sample-return missions, where robots collect stones for scientists to study in terrestrial laboratories. NASA and its Japanese counterpart currently each have missions at asteroids that do exactly that.
The sample-return format means that scientists have much more freedom to follow their curiosity, giving them the opportunity to answer questions one day that they do not yet know they should ask, Farley said. He pointed to the investigation of the infamous Allan Hills 84001 Martian meteorite, in which one argument that contained evidence of petrified life, since debunked, was based on the presence of small magnetic minerals. "You would never be able to make the measurements [on Mars] because you would never have dreamed of sending an instrument that could do that. " [Top 10 Discoveries by Mars Rovers Spirit & Opportunity: A Scientist’s View]
And of course there are all the limitations inherent in obtaining an instrument on Mars, Farley said – it has implications for the size, weight, force, sensitivity to radiation and more of an instrument. Unless we build a staggering advanced laboratory on Mars, we will always need to bring those samples home to study seriously, Bosak said. "It comes down to the laboratory, and not just one laboratory – multiple laboratories, really a complete program that is dedicated to clean samples in a clean way," she said.
This is much more plausible here on Earth, where NASA's next Mars mission, called the Mars 2020 rover and starting this year, comes into the picture. It will mimic the skeleton of Curiosity, but is tuned to finding traces of life, rather than just environments that have ever been suitable for it. And it will select and store fragments of intriguing Mars rocks, hoping that a future mission will come to retrieve them, and return about a pound (0.5 kilogram) of Mars rocks to terrestrial laboratories.
But at the moment NASA is not working on this future mission: Mars 2020 is the last Red Planet scheme, which the National Academies of Sciences has criticized in a report published on 7 August. The Mars 2020 team simply continues their own work in the hope that someone will eventually deliver them their souvenirs.
Of course, people are great at picking up trinkets during their travels, and if engineers have developed the ability to bring people back from Mars, they can certainly manage a few pounds of boulders. A manned mission would therefore probably bring the same benefits as a robot sample return shipment.
But perhaps the robots have earned this. Any indication that Mars was once habitable and can still hide traces of that life comes from robots, not from people on the ground, and finding life is perhaps not the best way to argue for a manned mission.
"The value of human exploration is exploration," said Bosak. "You can not deny the attraction of this, but that is a separate problem of being able to find life on Mars."