Robert Sanders, UC Berkeley
As a young girl growing up in Cincinnati, Shannon Curry repeatedly asked her parents about the night sky, especially the planets, but as non-scientists, they seldom had answers. “That is what college is for,” her parents told her.
So, she earned a B.S. in astrophysics from Tufts University and become a systems engineer at Lockheed Martin before entering the University of Michigan to complete a Ph.D. in atmospheric and space physics. Seven years ago, she joined the Space Sciences Laboratory (SSL) at the University of California, Berkeley, to focus on missions to the planets Mars and Venus.
Curry is now in a prime position to answer many of the questions she posed her parents more than 20 years ago. She has been appointed the principal investigator of MAVEN, the Mars Atmosphere and Volatile Evolution, one of three NASA satellite missions now orbiting the red planet and the only one run by a woman.
At the age of 38, she is also one of the youngest principal investigators of any NASA mission.
“I never imagined I would lead a mission to Mars,” said Curry, who is deputy associate director for planetary science and astrobiology at SSL. “My focus is to continue executing our mission and achieving our science goals. We have a killer team, so I am looking forward to the next chapter of MAVEN.”
Bruce Jakosky of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder, was the first principal investigator of the MAVEN mission to Mars. (Photo by Merry Bullock)
Principal investigators are scientists or engineers outside of NASA who bear responsibility for a mission’s success. The role of MAVEN principal investigator — until last month, a job filled by Bruce Jakosky of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder — includes managing operations, the orbit, the data pipeline and processing, fuel usage, and just making sure the spacecraft stays up and running until the end of the decade, Curry said, in part to relay data from the rovers on the surface back to Earth.
As the youngest of the NASA satellites orbiting Mars — the others are the 20-year-old Mars Odyssey and the 15-year-old Mars Reconnaissance Orbiter (MRO) — MAVEN is the main contact between Mars and Earth through the Deep Space Network.
“There is enormous responsibility on MAVEN to make it to the 2030 goalpost, because at some point, Mars Odyssey will be decommissioned, and the same thing with MRO,” Curry said.
Follow the water
As a planetary physicist, though, Curry’s primary interest is the science. In the seven years since MAVEN settled into orbit around Mars, it has contributed immensely to our current understanding of the planet’s history — in particular, why it lost its atmosphere and what happened to the oceans of water that used to cover the planet. Curry said that an atmosphere is critical to maintaining liquid water on the surface of any planet, and as soon as it disappears — something that happened on Mars some 4 billion years ago, early in our solar system’s history — so does the water. The question NASA has been asking about Mars for decades is: Where did that water go? The answer has implications for whether life ever arose on the planet, and if so, where it may be hiding today.
[illustration of MAVEN orbiting Mars]
This illustration shows the MAVEN spacecraft and the limb of Mars (Image courtesy of NASA/GSFC)
“We know 100% there was liquid water on the surface of Mars. We can see dry river deltas, we can see features on the surface that were carved or created in the presence of water,” she said. “So, with that geomorphic evidence, we know liquid water existed on the surface on a million-year timescale, though it could have even been a billion. That said, as the atmosphere eroded, as atmospheric pressure decreased, the water had to go either up or down. I think of MAVEN as on ‘Team Up.’”
In other words, from its orbit less than 100 kilometers above the surface, MAVEN’s instruments monitor the escape of gases upward into space. Scientists then use these numbers to project back in time to estimate when and how much water evaporated into space, as opposed to the water that froze out underground or at the polar caps. These estimates also give a measure of how much total water once filled the now dried-up rivers and oceans.
“An enormous amount got trapped in the crust, and an enormous amount escaped to space,” Curry said. “Given the current escape rate, we are looking at between half a meter and 10 meters of a ‘global equivalent layer’ of water, that is, if the whole planet had been covered in water. That comes just from atmospheric and ionospheric measurements by MAVEN. When you fold in what the rovers are telling us, in terms of soundings and sample analysis on the ground, I think it is more than that.”
As MAVEN principal investigator, Curry has already begun to outline MAVEN’s next chapter of science with the mission team, which involves not only atmospheric studies, but also measurements of the strength and distribution of magnetic fields on the surface.
“One of our biggest goals will be to study the Martian atmosphere under extreme conditions,” she said.
These extreme conditions are created by the sun, which began a new solar cycle last year and will become much more active over the next five years. Coincidentally, at the peak of the solar cycle, the Martian global dust storm season will begin. Global dust storms occur roughly every three Martian years and can last anywhere from two weeks to two months.
“It’s rare for these two events to overlap at exactly the same time,” Curry said.
The extreme activity of the sun during the first billion years of the solar system was what stripped away Mars’ atmosphere in the first place, she said, whereas Earth and Venus retained theirs. The reasons why these three planets suffered different fates have major implications for exoplanet studies, suggesting that planets may need more than just the right temperature — being in the Goldilocks Zone, or habitable zone, that allows liquid water to persist — in order to support life. Planets also may need a global magnetic field to protect the atmosphere from solar storms and perhaps volcanoes to replace the atmosphere eroded away by active stars like our early sun.
“I am ecstatic for the leaps we’ve made in exoplanetary exploration and science, but there is a lot we can learn from our own planets,” she said. “It is important for all of us in the planetary community to take our expertise about our particular target and start to piece together a larger picture about how we all got here, figuratively and literally.”
New energy and ideas
MAVEN was conceived by Jakosky, the late UC Berkeley physics professor Robert Lin, and Lin’s SSL colleague, Janet Luhmann, during an hour-long phone conversation in 2003 that ended with a decision to propose the mission to NASA. Jakosky assembled a MAVEN team that proposed and won the NASA MAVEN mission in 2007. The satellite was launched in November 2013, but Lin did not live to see this milestone: He died suddenly from a stroke in November of 2012.
So, while Lin recruited Curry to SSL even before she completed her Ph.D. — her thesis was about what MAVEN would detect on Mars — it was Luhmann who onboarded her and served as a mentor.
“Janet picked me up, and I came to work under her wing and tutelage,” Curry said. “I can’t speak highly enough about her mentorship to me. She is absolutely the epitome of poise, grace and hard work when it comes to science.”
As part of Curry’s transition to principal investigator, Luhmann will step down as deputy principal investigator, making way for SSL’s David Mitchell to assume that position. Mitchell has been project manager of MAVEN since its inception.
“She (Curry) brings energy and ideas that will take MAVEN into new science and applications territories, bringing its many types of observations to the attention of new audiences,” Luhmann said.
Jakosky emphasized that Curry’s experience as a planetary physicist, mathematician, statistician and systems engineer makes her more than qualified to lead the MAVEN mission.
“She knows how science and engineering work together,” said Jakosky. “She has a good thought process. During the various meetings, I watched her collect the information necessary to make thoughtful and intelligent decisions.”
Since coming to SSL, Curry put these skills to use as project scientist for the ESCAPADE twin-satellite mission to Mars, where she teamed with SSL’s Rob Lillis, and as the science lead for NASA’s Parker Solar Probe during its many gravity-assist loops around Venus, which are an opportunity to probe the planet.
As she takes the helm at MAVEN, Curry is excited about seeing early career scientists use data from the mission, as she has done since before arriving at SSL.
“You see graduate students and postdocs get really excited about their discoveries. It’s sort of a once-in-a-lifetime opportunity to get to work on data that no one else has ever seen from another planet and get to share that experience with others,” she said.
When not working, Curry can be found on the running trails in the nearby hills — she and her husband met at a local running club — or at a local climbing gym. Or, as of early this year, caring for her newborn. When Curry interviewed for the MAVEN principal investigator job in December, she was 8½ months pregnant and now has an eight-month-old boy, Jack.
“I’ve got my spacecraft baby and my human baby, and I love them both very much,” she said.