The Martian surface is hard, a dry, cold and irradiated environment. But the old Mars was perhaps habitable for microbial life because it supported the water. The rovers that will be on Mars in the coming years will search for biosignatures in Martian soil, drill and sample below the surface to find evidence of this ancient and potential life.
A NASA-funded study deployed a robotic rover in the Atacama Desert in 2013 as part of a test mission aimed at finding signs of life in another inhospitable environment. The Atacama Desert is the driest desert region on the planet with very little moisture or precipitation. Animals and plants are hard to find, but bacteria could be below the surface.
"The heart of the Atacama Desert in Chile is extremely dry and experiences decades without rainfall," said Stephen Pointing, author of the study and director of the science division of Yale-NUS College in Singapore, in a statement. "It has a high exposure to UV rays and is composed of a very salty soil.It is the closest match we have on Earth to Mars, which makes it very useful for testing simulated missions on this planet ",
The solar-powered autonomous rover has traveled 50 kilometers on two types of terrain similar to those he might encounter on Mars. One was a stony pavement of the desert and the other was sandy and typical of the desert environment. The rover also used a drill to collect 32 samples at 80 centimeters deep.
"We have shown that a robotic robot can recover the soil beneath the surface in the desert most resembling Mars on Earth," Pointing said. "This is important because most scientists agree that all life on Mars should take place under the surface to escape rough surface conditions where high radiation, low temperatures and lack of water make life improbable. "
In addition to the drill, the rover can map and analyze the landscape, visible habitat, and even geochemical characteristics with its mounted cameras and spectrometer.
The rover discovered unusual highly specialized microbe patches. Researchers believe that the uneven distribution is due to soil chemistry and lack of nutrients and water.
They compared the mobile samples with those they had manually taken in the desert. Microbial life was similar in both types of samples.
"We have found microbes adapted to high concentrations of salt, similar to what we can expect in the Martian basement," Pointing said. "These microbes are very different from those known until now at the surface of deserts."
Understanding the distribution of life in the Atacama Desert could help the strategy of rovers deployed on Mars.
"These results confirm a basic ecological rule that microbial life is uneven in the most extreme habitats of the Earth, suggesting that life on or on other planets may also have irregularities," he said. said Nathalie Cabrol and Kim Warren-Rhodes, co-authors of the SETI study said in a statement. "While this makes detection more difficult, our findings provide possible guidance for guiding the exploration of life on Mars, demonstrating that it is possible to detect life with search strategies and strategies." intelligent robotic sampling. "
In the future, rovers will have to dig deeper. Future studies will have to explore these capabilities.
"Martian missions hope to break through [2 meters] thus, having an Earth-based comparison will help identify potential problems and interpretation of results once rovers are deployed there, "the researchers said. Ecological studies allowing us to predict living areas for microbial communities in the most extreme environments of the Earth will also be essential for finding life on other planets. "