During a Thursday press briefing, NASA scientists said there is really only one way to determine, without a doubt, if samples collected on Mars by the Perseverance Rover that contain organic material also include evidence that life once existed on the Red Planet.
What’s the trick? Get the samples back to an Earth-bound laboratory for deep analysis.
And that’s an effort very much in the works thanks to a partnership between NASA and the European Space Agency that’s gearing up for a pair of launches that will begin a mission to travel to Mars, rendezvous with the Perseverance Rover on Mars’ surface, retrieve samples and return them to Earth, possibly as soon as 2033, according to NASA scientists.
The first physical evidence that some form of life may have existed on Mars billions of years ago when the planet’s surface environment was hospitable and included liquid water were first discovered by NASA’s Curiosity Rover nearly a decade ago.
Further evidence of organic compounds and other potential biosignature chemicals that hint at the possibility of some form of life have been unveiled by the Perseverance Rover and its set of more advanced scientific tools. But Perseverance is also equipped to gather and store samples, tasks it’s been engaging in since its successful Mars landing in February 2021.
Could there be life on Mars right now?
Perseverance project scientist Ken Farley, of the California Institute of Technology, said Perseverance has traveled to Jezero Crater, the site of an ancient Mars lake that includes a wide variety of rock and sedimentary samples carried into the area from once-flowing Martian rivers.
It is exactly the type of location that scientists believe has the best chance to include evidence, if it exists, of a past presence of life on the planet.
Farley also underscored that the current harsh conditions on Mars’ surface — one that is extremely dry, deeply cold and bombarded by high levels of radiation — leaves little chance of discovering any modern life forms.
“Jezero was selected for this mission because it meets several key mission goals,” Farley said. “It allows us to explore an ancient habitable environment, it allows us to seek evidence of possible Martian life in rocks deposited at that time about 3.5 billion years ago.
“And, I want to emphasize this mission is not looking for extant life, things that are alive today. Instead we’re looking into the very distant past when Mars’ climate was very different than it is today, much more conducive to life.”
Returning samples to Earth is key to answering Mars’ life question
Farley said Perseverance is gathering samples from an area in the Jezero Crater that has exposed layers of sedimentary rock, the kind of geologic formation that has the highest potential for holding key evidence for unlocking Mars’ ancient life mysteries.
“This specific area has probably the highest scientific value for exploration of the entire mission,” Farley said. “This is the site that brought us to Jezero Crater.”
Farley said rocks under investigation in the area “have the highest concentration of organic matter that we’ve yet found on the mission. And of course, organic molecules are the building blocks of life.” But, Farley also stressed that organic compounds and other potential signs of past organic life, so-called biosignatures, can come from other sources and are not, in themselves, definitive of past Martian life.
“Potential biosignatures is something that may have been produced by life but also could have been prod in the absence of life,” Farley said. “The key point about a potential biosignature is it compels further investigation to draw a conclusion.
“These rocks are exactly the kind of rocks we came to investigate both with the rover and its scientific instruments and to bring back to Earth so they can be studied in terrestrial laboratories.
“Time will tell what is in these rocks.”
How Mars samples will get back to Earth
Last month, NASA reported that it had, in partnership with the European Space Agency, finished the system requirements review for its Mars Sample Return Campaign and is nearing completion of the conceptual design phase for the mission.
The sample return program includes the launch of two spacecraft: one a Mars orbiter and the other, a Mars lander and retrieval package that also includes a small rocket that would carry samples retrieved from Perseverance off the surface for a rendezvous with the orbiter craft which will carry the Mars samples back to earth.
Lori Glaze, director of NASA’s Planetary Science Division, said the mission will be the first to return samples gathered on another planet to Earth and the first to launch a rocket from the surface of another planet.
“What’s really exciting is we have the technologies now to bring these samples back,” Glaze said. “We are now really in the position that these samples are so compelling we want to get them back.
“The Mars Sample Return Campaign that we are working on … is incredibly complex. But, we expect to have two launches from Earth later this decade. The Earth return orbiter that will carry the samples back to Earth is expected to launch in 2027. And, the sample return lander will actually launch a few months later in the spring of 2028.”
Glaze said the plan is for the sample return lander to rendezvous with Perseverance on Mars’ surface to collect the samples. But, should Perseverance be unable to make that meeting, the lander will also come equipped with two helicopters, similar to the Ingenuity drone that traveled to Mars with Perseverance, that could be deployed to retrieve samples.
If all goes to plan, Glaze said, the sample retrieval lander will be on the surface of Mars in 2030 and be back to Earth, with samples onboard, sometime in 2033.