Once it sets down on Mars on Thursday afternoon, a chief mission of NASA and Jet Propulsion Laboratory’s Perseverance rover will be to seek out signs of past life on the Red Planet, and scientists that control it are working to figure out how to recognize such clues when they see them.
The landing site for the rover, Jezero Crater, was selected because scientists believe it may have once possessed the ingredients necessary for life, JPL said in a written statement. But such life may not be easy to find, as it could be microscopic, as well extinct for millions or billions of years.
“To quote Carl Sagan, ‘If we see a hedgehog staring in the camera, we would know there’s current and certainly ancient life on Mars, but based on our past experiences, such an event is extremely unlikely,’” said JPL Planetary Science Directorate Chief Engineer Gentry Lee. “‘Extraordinary claims require extraordinary evidence, and the discovery that life existed elsewhere in the universe would certainly be extraordinary.’”
Jezero Crater is considered a promising place to look due to its ancient history as a large lake with a river delta, Mars 2020 Perseverance Rover Mission Deputy Project Scientist Ken Williford explained.
And while no hedgehogs are expected, Perseverance is equipped with a host of scientific instruments specially designed to detect “biosignatures” of past life.
“We expect the best places to look for biosignatures would be in Jezero’s lakebed or in shoreline sediments that could be encrusted with carbonate minerals, which are especially good at preserving certain kinds of fossilized life on Earth,” according to Williford. “But as we search for evidence of ancient microbes on an ancient alien world, it’s important to keep an open mind.”
Perseverance will also collect samples of Martian rock and soil and store them to be returned to Earth by a future mission for closer analysis, according to JPL’s Mars Sample Return Program Manager Bobby Braun.
“The instrumentation required to definitively prove microbial life once existed on Mars is too large and complex to bring to Mars,” he said. “That is why NASA is partnering with the European Space Agency on a multi-mission effort, called Mars Sample Return, to retrieve the samples Perseverance collects and bring them back to Earth for study in laboratories across the globe.”
Whether Perseverance finds solid evidence of prior life on Mars or not, the information it sends back to Earth will be invaluable, Williford said
“We have strong evidence that Jezero Crater once had the ingredients for life. Even if we conclude after returned sample analysis that the lake was uninhabited, we will have learned something important about the reach of life in the cosmos,” he said.
“Whether or not Mars was ever a living planet, it’s essential to understand how rocky planets like ours form and evolve. Why did our own planet remain hospitable as Mars became a desolate wasteland?” Williford said.
The answer to one of humankind’s oldest questions “may be awaiting us somewhere in Jezero Crater,” the JPL statement said. “NASA’s Perseverance rover will begin the process of finding out tomorrow.”
Landing is scheduled for 12:55 p.m.