Sally Kristen Ride was a physicist and a former NASA astronaut. In 1983, Ride became the first American woman to enter space as a crew member on space shuttle Challenger for STS-7. Her second space flight was in 1984, also on board the Challenger. Her post-NASA years were spent at Stanford University and University of California, San Diego. She holds the distinction of being the only person on both the Challenger and Columbia disaster commissions. She founded Sally Ride Science, a company that creates entertaining science programs and publications for upper elementary and middle school students. Ride authored many books on space aimed at children. Sally Ride died on July 23, 2012 at the age of 61.