Sarah Stewart Johnson is an American biologist, geochemist, astronomer and planetary scientist.
She joined Georgetown University in 2014[1] and is currently the Provost's Distinguished Associate Professor of Biology and the Science, Technology, and International Affairs program in the School of Foreign Service.
[3] She received her bachelor's degree from Washington University in St. Louis, where she was an Arthur Holly Compton Fellow and majored in math and environmental studies.
Her work involves the use of analog environments to study the habitability of the surface and subsurface of Mars and icy moons.
[11][12] She is a visiting scientist at NASA's Goddard Space Flight Center with the Planetary Environments lab.