September 17, 2004
At lunchtime, research scientist Dr. Michelle Santee often comes down from the clouds to sit outside near the fountain on JPL's main mall area. Santee studies clouds - in particular, polar stratospheric clouds, which have an important role in the development of the "ozone hole" over Antarctica. By coincidence, just steps away from her usual lunch spot, a small plaque honors the man who first sparked her interest in becoming a scientist.
"I was inspired by Carl Sagan," says Santee, who began her career navigating JPL spacecraft to other planets and now focuses on planet Earth. She's a member of the science team for the Microwave Limb Sounder, one of the instruments on Aura, NASA's newest Earth-observing satellite, launched in July. One of the sounder's major goals is to see whether the stratospheric ozone layer is recovering as expected, now that fewer chlorofluorocarbons are being released into the atmosphere. It will also help us understand how changes in the chemical composition of the atmosphere affect climate and measure some types of air pollution. An earlier version of the instrument flew on the Upper Atmosphere Research Satellite.
Santee uses data from the Microwave Limb Sounder and other measurements to study polar processes. She is especially interested in how polar stratospheric clouds form and their effect on atmospheric chemistry. "Under the very cold conditions of the polar stratosphere during the winter, clouds containing condensed water and nitric acid are common occurrences," says Santee. "These clouds facilitate the conversion of chlorine released from chlorofluocarbons into ozone-destroying forms. They also have a role in removing reactive nitrogen from the stratosphere, another important process for the stratospheric ozone issue."
Santee's interest in science didn't start with clouds. "I was always interested in the planets," she says, "but I first pursued it from an engineering point of view." She chose Cornell University, Ithaca, NY, where Sagan taught, for her undergraduate degree in mechanical engineering. After completing her master's degree in aerospace engineering at the University of Texas in Austin, she came to JPL to work on the navigation teams for Magellan and Mars Observer.
"The role of the navigation engineer is largely fulfilled once the spacecraft is in orbit around the planet," says Santee. "While I found it very interesting, I wanted to study the planets not just help spacecraft get there, so I went back to school to get my Ph.D. in planetary science." She attended the California Institute of Technology in Pasadena and wrote her thesis on the Martian atmosphere.
After she finished her degree, however, Santee had another epiphany along with a growing environmental consciousness. "As fascinating as Mars was, I decided I'd rather apply my skills toward making a difference to my own planet," she says.
She joined the Microwave Limb Sounder team as a post-doc in 1992, a year after the instrument was first launched on the Upper Atmosphere Research Satellite. Plans to build a new sounder for what would become the Aura mission were just beginning to be made, so she was able to be part of the project through most of its development. She got to see the new Microwave Limb Sounder for Aura being built in JPL's clean room, help identify the science goals for the mission, and witness its launch from Vandenberg Air Force Base in California. "It's going to be a much improved instrument," she says.
Santee grew up in Reading, Pennsylvania. While they aren't scientists, her parents, now retired, are avid amateur physicists. "They read and watch anything about string theory and the quantum universe," she says, "all that hardcore physics that scares me."
Though she doesn't share her parents' passion for quantum physics, Santee did inherit her love of history from them. She is particularly interested in art history and the history of polar exploration. "I'd love to go to Antarctica," she says. "I have a very romantic notion of it, and I think the scenery is beautiful."
For fun, Santee enjoys hiking and baking bread, but admits that she is currently without a kitchen, since hers is being remodeled. She expects soon to have a new source for baking and for science. With the launch of the new Microwave Limb Sounder on Aura in July, Santee expects her life to get a lot busier. "I hope to have lots of data pouring in."
Written by Rosemary Sullivant Media Contact: Alan Buis (818) 354-0474