Passage: In 1987, Ride left her position in Washington, D.C., to work at the Stanford University Center for International Security and Arms Control. In 1989, she became a professor of physics at the University of California, San Diego, and director of the California Space Institute. From the mid-1990s until her death, Ride led two public-outreach programs for NASA—the ISS EarthKAM and GRAIL MoonKAM projects, in cooperation with NASA's Jet Propulsion Laboratory and UCSD. The programs allowed middle school students to request images of the Earth and moon. In 1999, she acted in the season 5 finale of Touched by an Angel, titled "Godspeed". In 2003, she was asked to serve on the Columbia Accident Investigation Board. She was the president and CEO of Sally Ride Science, a company she co-founded in 2001 that creates entertaining science programs and publications for upper elementary and middle school students, with a particular focus on girls.According to Roger Boisjoly, who was the engineer that warned of the technical problems that led to the Challenger disaster, after the entire workforce of Morton-Thiokol shunned him Ride was the only public figure to show support for him when he went public with his pre-disaster warnings. Sally Ride hugged him publicly to show her support for his efforts.Ride wrote or co-wrote seven books on space aimed at children, with the goal of encouraging children to study science.Ride endorsed Barack Obama for U.S. President in 2008. She was a member of the Review of United States Human Space Flight Plans Committee, an independent review requested by the Office of Science and Technology Policy (OSTP) on May 7, 2009.

Question: Where did Ride gain employment after leaving her position?
University of California, San Diego