The first American woman in space has lost her battle with cancer.
Sally Ride, 61, died on Monday (23Jul12) after a 17-month battle with pancreatic cancer.
The physicist was aboard the Space Shuttle Challenger's 1983 mission into space. Ride helped develop the shuttle's robotic arm.
Paying tribute to Ride, NASA Administrator Charles Bolden says, "The nation has lost one of its finest leaders, teachers and explorers."