Conversation so far:
When did Ride leave NASA?
In 1987, Ride left her position in Washington, D.C., to work at the Stanford University Center for International Security and Arms Control.
What did Sally Ride do at the Stanford Center?
She became a science fellow at the Center for International Security and Arms Control at Stanford University.

Question: How long was she there?
Self-contained rewrite: How long was Sally Ride there?