Sally Ride

She did well in high school, but lacked confidence and worried her science studies would get harder."I wasn't sure I was smart enough to go on," she said. But her teachers encouraged her to continue.

She went on to receive her bachelor's, master's and doctoral degrees from Stanford University. A few months before she completed her doctorate in physics, she spotted an ad in the student newspaper that said NASA was looking for astronauts. Women were encouraged to apply.

"I literally applied that afternoon,"she said. Ultimately she was selected for astronaut training from a field of more than 8,000 applicants.

Ride flew in space twice aboard Challenger"in June 1983 and October 1984"and was preparing for a third mission aboard that shuttle when tragedy struck. She was on a commercial flight to her home in Houston on Jan. 28, 1986, when Challenger exploded shortly after launch, killing all seven crew members.

The airline pilot came on the intercom to tell the passengers what had happened. Ride immediately pulled out her NASA badge and went to the cockpit so she could sit in the jump seat and listen to the radio transmissions from NASA. She rode there for the rest of the flight, devastated at what had just happened to people she knew very well. Four of the Challenger crew had been in Ride's astronaut class, and she had become friendly with teacher Christa McAuliffe, who had trained at the Johnson Space Center for three months.

Ride served on the presidential commission headed by former Secretary of State William P. Rogers that investigated the Challenger accident. After the shuttle fleet was grounded, she was one of many astronauts who resigned from NASA. She took a two-year fellowship at the Center for International Security and Arms Control at Stanford University. In 1989, she became a physics professor and director of the University of California's Space Institute at UC San Diego, where she became involved in educational projects with middle-school students.

But she wanted to start a program that was national in scope. In 2001, she founded Sally Ride Science, a company that supports children's interest in science, math and technology through its science fairs, camps, books and teacher training.

"We believe that science is fun, that kids, particularly in elementary school enjoy science," she said."You really don't need to convert kids to science, you just need to sustain the interest that they naturally have in science."

Ride encourages parents and grandparents to take children to science centers and science activities, and to have the same expectations for girls as for boys.

Ride has written several children's books about science, including Mission: Planet Earth. Sally Ride Science publishes a Cool Careers series of books, including Cool Careers in Space Sciences and Cool Careers in Math, aimed at fourth- through eighth-graders, which show men and women from diverse backgrounds working as scientists.

"It still is much more common for people to picture a scientist as a male and to maybe subtly, maybe even subconsciously, encourage young boys toward those careers more than young girls,"she said.

While several other big-name former astronauts have criticized President Obama's plan to curtail NASA's involvement in the low-Earth orbit business and refocus the agency on asteroid and Mars exploration, Ride is a supporter. Last summer, she was on a panel that looked at NASA's human spaceflight program and recommended the private sector take over most low-Earth orbit transportation. "I think that by and large this is a plan that frees NASA to look toward the more challenging aspects of exploration beyond low-Earth orbit," Ride said.

Married briefly to astronaut Steve Hawley in the 1980s, Ride never remarried and has no children. She lives in San Diego and enjoys running, frequent workouts and being outside. She gave up playing tennis when she was 25. "When I stopped playing competitive tennis," she said laughing, "I wasn't able to make the transition to play it for fun."

Recently, Ride has been pictured in ads for Louis Vuitton with former astronauts Jim Lovell and Buzz Aldrin recalling their journeys in space.

Kitty Bennett is a news researcher and writer based in St. Petersburg, Fla.