Nordonia grad has her sights on Mars
Geologist part of NASA mission teams
MACEDONIA — It was about 15 years ago that Linda Kah’s geology career suddenly went on an upward trajectory.
The Nordonia High School graduate got a phone call from someone she did not know asking if she was interested in taking part in NASA’s Mars Curiosity rover project. Not knowing much about Mars, she was skeptical at first but eventually agreed.
“I said, ‘Yeah, what the heck,’” she said.
Kah said she apparently did a good job because she is now involved with Mars 2020, even taking a planning leadership role in the mission that launched July 30.
“Interestingly, I was never all that interested in astronomy or the planetary sciences,” said Kah. “I liked the Earth. I liked learning about the history of the Earth.”
A long-time dream
Kah grew up in Macedonia. Her mother, Ann, lives there. Her father, David, died about eight years ago. She said her interest in geology was sparked early by a large leather chest filled with rocks, minerals, and fossils in the basement, a “pirate treasure chest” that her parents brought back from New Mexico where they lived when they married.
“I believe, if I remember right, that I declared to my kindergarten teacher at Ledgeview [Elementary School] that I was going to be a geologist when I grew up. So that was always there,” she said. “Then it must have been first or second grade, we went out to Canyonlands [National Park] in Utah on vacation and it absolutely struck me that geology was going to be my life.”
Shortly after she graduated from high school in 1986, she headed for the Massachusetts Institute of Technology for undergraduate work. She earned her Ph.D. in geology from Harvard University in 1997 and is now a professor of geology at the University of Tennessee, Knoxville, where she started working in January 2000.
What NASA wanted
Kah specializes in sedimentary geology, the study of rocks like sandstone.
“Rocks that are composed of material that had once been transported across the surface of the Earth by wind or water,” she said.
This work has led into the realm of biology, with much of her time spent looking for evidence of early microbial life in nearly billion-year-old rocks.
Her work has taken her all over the world for field work: the Canadian Arctic, Russia, India, China, the Andes of Argentina. She had just returned from the Sahara Desert in West Africa when she got that phone call around 2005. Kah said that despite her initial uncertainties, the offer came at a good time. Field work in some parts of the world was becoming dangerous and she was thinking about taking a break from all the traveling anyway to start a family with husband Colin Sumrall, a paleontologist who has helped her in her work.
She said it makes sense that NASA was looking for sedimentary geologists in particular for a Mars mission.
“What we’ve learned is when we land a rover on the surface of Mars, what it is largely going to see is a sedimentary world,” she said. “It’s going to see a surface environment that’s going to have sedimentary rocks. It’s going to see wind blowing and dust blowing and sand dunes.”
Curiosity launched in November 2011 and landed on Mars the following August, with the rover exploring Gale Crater, a little south of the martian equator.
According to NASA’s website: “Curiosity set out to answer the question: Did Mars ever have the right environmental conditions to support small life forms called microbes? Early in its mission, Curiosity's scientific tools found chemical and mineral evidence of past habitable environments on Mars. It continues to explore the rock record from a time when Mars could have been home to microbial life.”
Kah said the crater appears to have been a lake at some point in the distant past, with water levels rising and falling, leaving layers of sediment.
“So we’re really trying to sort the ebb and flow of the climate history that we’re recording in this lake,” she said.
A second mission
Kah has been working on the Mars 2020 mission for about four years and this time has taken some leadership responsibilities, particularly in helping in the selection of a landing site through analysis of data collected by satellites orbiting Mars. One of the pleasures of this is that she was allowed to bring some of her students in as volunteers.
“A wonderful opportunity to give a handful of students the hands-on activity of physically helping in the planning of a Mars mission,” she said.
The result of this work is that Mars 2020’s Perseverance rover is scheduled to land in Jezero Crater, a little north of the equator, on Feb. 18, 2021. Planning continues, meanwhile.
“Once we land, yeah, a lot of our plans will go out the window,” said Kah. “But we’re spending a lot of time this year and while the spacecraft is in transit to Mars, thinking about what we are doing once we land.”
Like Gale, said Kah, Jezero also shows signs of having once been a lake with rising and falling water levels. She said there are signs of a river that brought water in, as well as a delta, which only forms when there is standing water like a lake. And the existence of water is important because of its part in biological processes.
There’s also something else that can be seen at Jezero. Spectrum analysis of rocks in the area indicate some fall into a category of minerals called carbonates. A common carbonate on Earth is limestone, which is often formed from the ancient remains of shells and corals.
“We relate limestone to life,” said Kah.
Kah said much of what these missions are about concern looking at the geologic features of Mars to determine the past environment and whether it could have supported life. One important difference, however, between Curiosity and Mars 2020 is that the latter is designed to bring back rock samples when the spacecraft returns in 2031. Kah said she expects to remain involved during that time, but she expects it will be upcoming scientists studying those specimens.
“I’m actually due to retire in 2032, so I will probably never work on the return samples,” she said. “That’s for the next generation of scientists. But my job as part of this mission is to get the absolute best potential samples to bring home.”
Go to https://mars.nasa.gov/mars2020 for more information about the Mars 2020 mission or https://mars.nasa.gov/msl/home for more information about Curiosity.
Reporter Jeff Saunders can be reached at firstname.lastname@example.org or @JeffSaunders_RP.