Sally Ride, the first US woman to travel to space, died Monday at age 61, her company and NASA said.
Ride's flight aboard the shuttle Challenger in 1983 made her the first American woman in space on a six-day mission that deployed two satellites. She flew on a second shuttle mission a year later.
"Sally Ride broke barriers with grace and professionalism - and literally changed the face of America's space programme," NASA administrator Charles Bolden said. "The nation has lost one of its finest leaders, teachers and explorers.", dpa reported.
Ride joined NASA in 1978 in the first astronaut training class to include women.
After leaving NASA in 1989, she became a professor at the University of California at San Diego and sought to encourage girls to pursue careers in science through her company, Sally Ride Science.
She served on the investigation boards that looked into the Challenger and Columbia shuttle disasters and helped set the course for NASA's space programme in a review of human spaceflight plans in 2009.
She had suffered pancreatic cancer for 17 months, her company said in a statement.