Sally Ride, the first American woman to fly in space and University of California at San Diego physics professor emeritus, died Monday from pancreatic cancer. She was 61.

"Sally Ride broke barriers with grace and professionalism – and literally changed the face of America’s space program," said NASA Administrator Charles Bolden. "The nation has lost one of its finest leaders, teachers and explorers. Our thoughts and prayers are with Sally's family and the many she inspired. She will be missed, but her star will always shine brightly."

Ride's historic flight into space captured the nation’s imagination and made her a household name. She became a symbol of the ability of women to break barriers and a hero to generations of adventurous young girls. After retiring from NASA, Ride used her high profile to inspire young people, especially girls, to stick with their interest in science, to become scientifically literate, and to consider pursuing careers in science and engineering.

Ride was a physicist, science writer, and the president and CEO of San Diego-based Sally Ride Science, which provides classroom materials, programs and professional development training for teachers, according to her website, sallyridescience.com.

Karen Flammer, a founder of Sally Ride Science and physicist at UCSD, first saw Ride’s passion when they were working to start the EarthKAM program for students.

“It was what she loved doing. She was determined to get the project running and get it accessible to students,” said Flammer. “Her passion was infectious. It definitely changed my career.”

After staying up all night working with Ride, Flammer decided to shift her career focus to educational outreach. Flammer spoke with Ride during her last few days.

“She said she wants Sally Ride Science to continue with all of the educational programs,” said Flammer. “Her legacy at UCSD, she wants EarthKAM and MoonKAM both to survive and keep going. Her wishes are that all of her projects outlive her.”

She said Ride was “amazing” to work with and is a national hero and role model for so many people.

“Michelle and I were deeply saddened to hear about the passing of Sally Ride,” President Barack Obama said in a statement. “As the first American woman to travel into space, Sally was a national hero and a powerful role model. She inspired generations of young girls to reach for the stars and later fought tirelessly to help them get there by advocating for a greater focus on science and math in our schools. Sally’s life showed us that there are no limits to what we can achieve, and I have no doubt that her legacy will endure for years to come. Our thoughts and prayers go out to Sally’s family and friends.”

Ride was in charge of education and public outreach for MoonKAM, part of NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission, in which two satellites are orbiting the moon to map its gravitational field in unprecedented detail.

Middle school students around the country can request that special cameras aboard the twin satellites take photos of particular lunar features.

The requests go to UCSD's mission operation center, where 27 undergraduate students direct GRAIL's cameras to take the requested photos, and then upload them to the Internet for viewing.

Like these young students, Ride always had a love for science. She was born in Encino, Calif., on May 26, 1951, and while other young girls had Barbie Dolls, Ride played with a chemistry set and telescope.

She received bachelor’s degrees in physics and English from Stanford University and was about to finish her doctorate in physics when she saw NASA was looking for astronauts — and women were allowed to apply.

Ride was one of 8,000 people to apply to be an astronaut at NASA. Thirty-five people, including six women, were chosen to join the astronaut corps, and NASA selected Ride as an astronaut candidate in January 1978.

During astronaut training Ride learned parachute jumping, water survival, weightlessness, radio communications and navigation. She discovered her love for flying and worked on the ground as a communications officer during the second and third flights of the space shuttle Columbia. She was a member of the team that developed the robot arm used by shuttle crews to deploy and retrieve satellites.

Ride was selected as a mission specialist for mission STS-7 aboard the shuttle Challenger. On June 18, 1983, Ride strapped in and blasted off from Kennedy Space Center in Florida and became the first American woman in space. Her second flight was for STS-41-G on Oct. 5, 1984.

Ride was chosen for a third scheduled flight, but training was cut short in January 1986, when the space shuttle Challenger exploded in midair shortly after take-off. The entire crew of seven was killed.

Ride served on President Ronald Reagan's Rogers Commission, investigating the explosion. Perhaps the most important recommendation the commission made was to include astronauts at management levels in NASA.

“Sally was a personal and professional role model to me and thousands of women around the world,” said NASA Deputy Administrator Lori Garver. “Her spirit and determination will continue to be an inspiration for women everywhere.”

Ride was assigned to NASA headquarters as special assistant to the administrator for long-range and strategic planning. There she wrote “Leadership and America’s Future in Space,” and became the first director of NASA’s Office of Exploration.

She retired from NASA in 1987 and became a science fellow at the Center for International Security and Arms Control at Stanford University, before joining the faculty at UCSD in 1989. She was a professor of physics and director of the California Space Institute. In 2001, she founded Sally Ride Science, to motivate youth to pursue their interest in science and consider careers in science, technology, engineering and math.

Ride wrote seven children’s science books and initiated and directed NASA-funded education projects. She was a member of multiple committees and boards and received numerous honors and awards. She was inducted into the National Women’s Hall of Fame, the California Hall of Fame, the Aviation Hall of Fame, and the Astronaut Hall of Fame, among other awards.

In addition to Tam O’Shaughnessy, her partner of 27 years, Ride is survived by her mother, Joyce; her sister, Bear; her niece, Caitlin, and nephew, Whitney; her staff of 40 at Sally Ride Science; and many friends and colleagues around the country.