The search for ancient life on Mars

The first year of the Perseverance rover’s mission to Mars captured the imagination of scientists and the public with an interplanetary helicopter flight and the first chance to hear the sounds of the red planet.

But two University of Cincinnati doctoral students say the best is yet to come in the second year, when the rover and their Perseverance science team begin searching in earnest for ancient life on another planet.

UC College of Arts and Sciences geology students Desirée Baker and Andrea Corpolongo work on a NASA science team using the rover and its helicopter companion, Ingenuity, to explore the Jezero crater near the delta of an ancient river that may hold clues for the first known extraterrestrial life.

Andy Chaya, an associate professor at the University of California, served on NASA’s advisory board that chose where to send the rover for the best chance of finding evidence of ancient life. Now he and his two students are members of the mission’s science team, which is helping NASA study the red planet to answer fundamental questions about the origins of life in the universe.

One primary task of the mission: collect rock samples on the surface of Mars to return to Earth on a future mission.

Czaja is one of 16 scientists worldwide appointed in June to a new NASA science group that will plan how the global scientific community will share and study these samples. The team includes experts in geology, geochemistry, planetary physics and epidemiology, among others.

“Mars is at the frontier of science. I’m excited and honored to be a part of it,” said Czaja, who studies Precambrian paleobiology, astrobiology and biogeochemistry.

Baker and Corpolongo work in shifts as tactical documentarians, taking notes on daily decisions and their rationales to help keep the hundreds of other members of the science team informed and back up to speed when they’re not working. In particular, Baker documents decisions and discussions about an instrument called SHERLOC, which uses cameras, spectrometers and a laser to search for signs of past microbial life on Mars.

“Every day on Mars is called a salt. For each day’s planning, we document what the pilot and scientists have prepared for the next salt,” Baker said.

The scientific team has a strong research spirit, she said.

“It’s mind-boggling to think about,” she said. “You’re exploring another planet, seeing things never seen before, and helping to interpret and share them.”

The rover performs tasks in both daylight and darkness, so science team members work unusual hours during the Martian solstice, which is 37 minutes longer than Earth’s 24-hour day.

Corpolongo also served as the campaign’s execution documentarian, planning the mission two days ahead of the tactical team.

“This team will put together a plan for two salts in advance if everything goes perfectly,” Corpolongo said. “Then, at the start of each tactical shift, you look at the previous campaign’s performance document report to get a high-level picture of what’s going on today.”

Normally, the rover’s route and goals go according to plan, but when there are surprises or challenges, the campaign execution team adjusts accordingly, she said.

“I call it a science party. It’s hard for me to put into words how cool it is to be a part of this international mission with eyes from all over the world,” Corpolongo said.

Baker said that after its historic flights proved successful, the Ingenuity helicopter served as an advance scout for Perseverance, helping to identify potential traps and intriguing rocks along its designated route.

“This was an unexpected bonus for Ingenuity. Now we’re finding new ways to use it,” Baker said. “The rover has to be careful where it drives. It is a desert environment with soft sand.

Czaja said he doesn’t know if Perseverance will find evidence of ancient life on Mars. But he has confidence in the rover’s ability to search for him. And the site NASA has chosen for the search is promising, he said.

The Jezero crater is located next to what scientists believe to be an ancient river delta. On Earth, these are likely places where evidence of ancient life lurks, as organic life would be swept downstream to this stagnant water, where it would quickly be covered and preserved in fine sediment.

“It looked like a river delta from orbit, but there are things you can’t see from orbit that we have now that show it’s actually a delta,” Chaya said.

If Perseverance finds what appears to be tangible evidence of ancient life, confirmation will likely have to await a return mission to retrieve the samples the rover is collecting. These analyzes are bound to reveal other surprises on Earth.

“That’s one of the great things about sample returns. You’re not just doing it to answer the questions we have today,” Chaya said. “There may be questions that no one has thought of yet. The person who thinks about this question may not be born yet.”

Perseverance had a string of successes from its launch to landing on Mars seven months later via Skycrane, a rocket-powered descent vehicle that lowered the rover to the surface via cables. Before launch, NASA engineers described the spacecraft’s final descent through the thin Martian atmosphere as “seven minutes of terror.”

Czaja and other members of the science team tuned into JPL’s live feed to watch as they learned the fate of the spacecraft, deploying its parachute, ejecting its heat shields and lowering the rover via cables to the Martian surface.

“Watching the landing, I remember being too excited to sit down,” Chaya said. “My heart was in my throat. Suddenly a picture of the underside of the rover and its surroundings on Mars appears.

Persistence was willing to explore.

“There is a really big question as to whether we will find evidence of ancient life on Mars. Is it the same as ancient life on Earth? Did life on both planets have the same origin?” Corpolongo said. “There are so many questions.”

During the first year of the mission, Czaja was given a chance to name a geographic feature on Mars according to the naming conventions established for each mapped quadrant. NASA has created a list of approved names associated with national parks around the world. One quadrant was connected to the Verdon Natural Regional Park in France, so Czaja named the Mount Gourdan ridge for a feature in the Alps.

“It was quite exciting. When you work day to day, you kind of lose sight of that. But when you step back, it makes you think, ‘This is really exciting,'” Chaya said.

Czaja said it was fun to contribute to the mission’s decision-making. Each choice has costs, risks and benefits to consider, he said.

“We’re a bunch of scientists, so we like to argue about the merits of our ideas,” he said. “There are so many things we would like to explore. You want to be as efficient as possible and complete all mission objectives in the allotted time.

A lot can go wrong on a mission as complex as this endeavor, so each day’s work is valuable, presenting tantalizing scientific opportunities, Chaya said.

“You’ll never know if you stop looking. It could be around the next bend or over the next hill,” Chaya said.

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