“Touchdown Confirmed!”: Sarah Sherman Reflects on Six Years of Work on NASA’s Perseverance Rover

Courtesy of Princeton University
Courtesy of Jenny Savino
Courtesy of Princeton University

After NASA scientists spent years locating and analyzing an optimal location for rover landing in efforts to find evidence of biological life on Mars, NASA’s Perseverance Rover successfully landed on Mars on February 18, much to the excitement of the Jet Propulsion Laboratory (J.P.L.) team. Andover alum and J.P.L. cognizant engineer Sarah Sherman ’04 was among the many team members cheering the rover on behind Zoom screens.

The Perseverance Rover decelerated from 15 times the speed of a bullet to land inside Jezero Crater, the site of an ancient lake on the surface of Mars and will begin collecting data.

Perseverance is the first rover that is able to drill and cache rock samples with its new coring drill. Sherman was a member of the team that worked for six years designing and producing the sample tubes to store the rocks and regolith collected from Mars.

“I was the Cognizant engineer for the sample tubes and the sample tube storage assembly. There are 43 sample tubes that will contain rock and regolith on Mars. My job was designing and fabricating those parts. I was part of a very large team that did that. The Cognizant engineer is the point person though for it,” said Sherman.

The sample tubes on Perseverance are made from titanium, a strong metal suited for space, and encased with white ceramic to help regulate the internal temperature. After collecting rock samples, the rover will then store them for a future mission to collect and send [them] back to Earth to further examine and study them.

“Up until now, whenever we go to Mars––we’ve sent a few rovers there and a few landers there–we do all of our science on Mars. So you basically bring your laboratory there and you have little miniature instruments that can measure what the material is on Mars and you can take photos of it. It’s like bringing your chemistry lab to Mars… Ideally what we’d like to do is bring some of the Martian rock and regolith back to Earth. We can use all of the world’s world-class laboratories to analyze it and learn about traces of ancient life,” said Sherman.

Though the project successfully landed the rover on Mars, the team did not do so without struggling. The biggest challenge Sherman’s team faced was adhering to the guidelines of planetary protection, meaning keeping Earth and Mars safe from contamination of each other. Everything found on Mars should come from only Mars and anything from Mars shouldn’t be released into Earth. In fact, to protect the Martian samples, Sherman had various restrictions on elements she could and could not use for safety and cleanliness purposes.

“Cleanliness was probably the biggest challenge… usually when you fabricate something there’s contamination in the air. The biggest contamination element was carbon. There’s a lot of knowledge that can be learned from carbon, mostly for finding traces of biological life, and it turns out that little specks of carbon on the sample tube look exactly like ancient microbial life. We spent a year trying to figure out how to get rid of this carbon and we had no idea where it came from,” said Sherman.

After six years of hard work, the rover launch was an exciting and nerve-wracking experience for Sherman and her team. Considering that only about half of all attempted landing attempts on Mars are successful, Sherman feared that Perseverance would fail. 

“If it had not worked, I won’t say that those six years were wasted, but that would have been a major bummer because our hardware hadn’t actually been able to work. We were all cheering for them in the background, hoping that it would work, so that we can do the important science that we were really trying to get. I was sitting at home with my fiance, who also works at J.P.L. We were both sitting there cheering it on from our Zoom screens and in our pajamas,” said Sherman.

When Sherman was a Junior at Andover, she wrote down her goal of working at NASA and building a robot to walk on Mars. Right now, she’s managed to accomplish those goals, nearly 20 years later. Andover helped Sherman set lofty goals for herself. From building a go-kart as the first female member of the then-new engineering club at Andover to working on rovers to send to Mars, Sherman has come a long way. She remembers her chemistry teacher, David Stern, who inspired her to work hard.

“Dr. Stern was a huge influence because he had worked in the industry before, not just in academics his whole life. He told me if you want to work at a place that actually builds stuff, here’s the stuff you got to learn and these are the classes to take. He challenged me to take tough classes throughout my high school and even college,” said Sherman.

Designing for Perseverance is only a part of Sherman’s long journey with J.P.L. Since her sophomore year of college, she has been working with J.P.L. through various projects, such as the Curiosity Rover, to advance the world of science and mechanics. According to Sherman, she loves her job and plans to continue working with J.P.L. in the future.

Sherman said, “I thought that J.P.L. as a whole was really a challenging place to work, but I respected everybody I worked with a lot, everyone was top notch… I love J.P.L. and I could envision myself working here my whole life… Someday, I’d like to be a leader of a larger team at J.P.L. I worked on the Earth Science Mission, I’ve worked on a Mars mission, right now I’m working on a mission going to Jupiter called Europa Clipper. I just want to keep doing what I’m doing.”