It's the birthday of Sally Ride, who was born in 1951 in Los Angeles, California. Ride earned a PhD in physics at Stanford University in 1978 with a thesis on the interactions of x rays with the interstellar medium. That same year, she was selected by NASA for its astronaut training program. Ride became the first American woman in space, when in June 1983 she served as a mission specialist aboard STS-7, a space shuttle mission that launched two communications satellites and conducted a range of microgravity experiments. Her second space shuttle mission took place a year later. She would have gone into space a third time if not for the Challenger disaster of 1986, which grounded NASA's space shuttle fleet. Ride served on the committee that investigated the disaster's causes. She returned to California to become a physics professor at the University of California, San Diego. Besides researching and teaching physics, Ride led programs and wrote books to encourage children to study science. She died of pancreatic cancer in 2012.
