On June 18, 1983, Sally Ride became the first American woman in space. She flew on the space shuttle Challenger on a six-day mission. She had previously helped build the shuttle's robot arm, which she then operated in space. In addition to being the first American woman to go to space, at age 32, she was the youngest astronaut in space.
(As with many space-related firsts, that "American" qualifier is important. The Soviet space program had sent two women cosmonauts into space well in advance of Ride: Cosmonaut Valentina Tereshkova flew all the way back in 1963, and Svetlana Savitskaya in 1982. They also sent various younger people to space, including Tereshkova.)
Ride represented a change in the previously completely male astronaut program. Although NASA had unofficially tested women in the late 1950s as part of the Mercury program, the idea of sending women into space was quickly discarded. NASA policy for decades was that only men would be considered as astronauts. It took until 1978 for NASA to change the policy—that year, six women became astronauts: Sally Ride, Judith Resnik, Kathryn Sullivan, Anna Fisher, Margaret Rhea Seddon, and Shannon Lucid.
"The engineers at NASA, in their infinite wisdom, decided that women astronauts would want makeup—so they designed a makeup kit. A makeup kit brought to you by NASA engineers ... You can just imagine the discussions amongst the predominantly male engineers about what should go in a makeup kit."
Ride held a Ph.D. in astrophysics, two bachelor's degrees (English and physics), and had served as CapCom (Capsule Communicator) for the second and third shuttle flights, STS-2 and -3. She was an accomplished pilot and athlete, as well as a Presbyterian elder. She was closely connected to Challenger, performing two missions on it and losing four fellow members of her 1978 class when it exploded.
After her astronaut career concluded, Ride served on both the Challenger and Columbia disaster review panels. During the former, she leaked vital information about the Challenger disaster (o-ring engineering reports), though this wasn't broadly known until after her death. She wrote educational books and founded Sally Ride Science. She was asked to head up NASA by the Clinton administration, but declined.
Ride died in 2012 from pancreatic cancer. Her obituary made news for quietly mentioning that she was survived by her partner of 27 years, Tam O'Shaughnessy. Although Ride had come out to her family and close friends, the obituary was the first public statement that she was gay. It was also the first time most people found out she had been suffering from pancreatic cancer; she asked that donations in her memory be made to a fund devoted to studying that form of cancer.