For AAAS Fellow Carol Polanskey, Ph.D., the first glimpses of a never-before-seen celestial body elicit feelings of grandeur, rivaled only by another of life’s more common milestones: the birth of a child. As a mother and National Aeronautics and Space Administration (NASA) scientist, Polanskey knows the exhilaration of both.
“You’ve been carrying a baby around for nine months, and now you get to know them,” she says. “It’s the same feeling … finding a new world and getting to know what it’s all about.”
Growing up, Polanskey loved science fiction books and Star Trek. She studied physics and astronomy at the Pennsylvania State University before an internship at the Lunar and Planetary Institute in Texas introduced her to planetary science.
“I learned that you can study other planets the same way you would study the Earth with geology,” she says. “They are different planets. They have a lot more uncharted territory that needs to be understood.”
Polanskey went on to get her master’s degree in geophysics and a Ph.D. in planetary science from Caltech. Her work focused on impact craters, like the ones visible on the moon. Polanskey is now a principal science systems engineer at NASA’s Jet Propulsion Laboratory in Pasadena, California. Her role in planning the successful retrieval of scientific data from a mission begins years before the spacecraft lifts off the ground. The stakes are high. Space missions cost millions of dollars. Each craft NASA launches has limited time to answer scientific questions.
“Sometimes people think all you do is send a spacecraft out somewhere and by its very nature of being in the proximity of that planet, it will give you what you need to know,” Polanskey says. “There’s an awful lot of planning to figure out what data you’re going to acquire and how you’re going to go about doing it.”
Polanskey helps draft processes for both ideal and contingency situations. For example, she helps prioritize scientific data points in the event a mission is cut short.
To be successful, she imagines everything that could go wrong. Her first taste of space travel’s unpredictability came from the Galileo mission, which she joined in 1988, one year before launch.
Galileo, whose aim was to study Jupiter and its moons, achieved other notable discoveries, such as becoming the first spacecraft to visit an asteroid and provided the only direct observations of a comet colliding with a planet.
At one point, though, the mission came dangerously close to failure. In 1991, Galileo was set to unfurl its 16-foot-diameter high-gain antenna to quickly send data back to Earth. It did not deploy. Fortunately, the team had a plan. From the ground, engineers made changes to the spacecraft’s software to leverage Galileo’s low-gain antennas – the size of dinner plates, Polanskey says – for data and image collection. This process took several years, as Galileo did not reach Jupiter until 1995.
“I was part of figuring out what science was critical for us to obtain and how to get that data back as efficiently as possible,” Polanskey says. “At the end of the day, we succeeded. You rarely see it mentioned that there was an anomaly at all. You have to search to find out that it was a very crippled spacecraft.”
In 2003, Polanskey joined NASA’s Dawn mission, which visited the giant asteroid Vesta and dwarf planet Ceres in the main asteroid belt between Mars and Jupiter. Scientists previously speculated in the 1970s that meteorites found on Earth were once part of Vesta, suggesting a collision at some point in the distant past. Besides this hypothesis, NASA only had blurry pictures taken from the Hubble Space Telescope.
“Aside from that, we didn’t know much more,” Polanskey says. “We knew its size and shape, but we didn’t know anything about its gravity.”
Polanskey helped work out a plan to reach Vesta, which involved arriving at high orbit to categorize its key elements before getting closer. Dawn launched in 2007. In 2011, it arrived at Vesta, leaving for Ceres in 2012. During this journey, Dawn experienced failures with three of its four reaction wheels, which spin like a gyroscope to precisely point the spacecraft. Luckily, Polanskey and the flight team planned ahead for this, based on knowledge of failures in prior missions. Engineers repurposed Dawn's hydrazine thrusters, which contain a limited supply of rocket propellant, to maneuver the spacecraft.
“We figured out how to get the exact same science data we intended to get in the first place by operating the spacecraft in a different way,” she says.
In her role, Polanskey learns about all aspects of the mission – from the craft’s thermal properties to communications systems – in order to understand how they impact the scientific goal. This has expanded her knowledge outside her original realm of study.
Currently, Polanskey is the Project Scientist on the Psyche mission, a not-yet-launched trip to a metal-rich asteroid between Mars and Jupiter. The asteroid interests scientists as it is believed to be an exposed metal core of an early planet, one of the building blocks of the solar system.
“It just adds another piece to the puzzle of how the solar system was created,” Polanskey says. “When we get there, it will be more interesting than we ever dreamed."