MORRISVILLE, N.C. – From sleeping weightless to seeing the beauty of the Earth from so far above, Sally Ride gave young girls a pep talk about the wonders of space and a career in science on Thursday.

But Ride, the first U.S. woman in space when she flew aboard the shuttle Challenger in 1983, didn’t need a long explanation to describe her most memorable moment as an astronaut.

“Launch,” she said without hesitation and breaking into a smile.

“It is just an instant that you never forget.”

And America, as well as the world, will never forget Ride, who helped pry open the doors at NASA for women in January of 1978.

A physics graduate from Stanford who grew up loving science as a child in Los Angeles, Ride recalled knowing “instantly” what she wanted to do when she saw a NASA astronaut recruiting advertisement in the university newspaper.

It’s hard to believe that 24 years have passed since that flight and that Ride, with her head of long, curly hair and the irrepressible smile of youth, turns 56 on May 26. She is on a new mission now when not teaching college courses or writing books. Her goal now is to encourage more young girls to become engineers.

That goal is what brought Ride to Lenovo’s new world headquarters in Morrisville. Lenovo signed on as a sponsor for a 24-hour marathon Web cast designed to get more women on the science track.

Helping her as co-host was Fran O’Sullivan, a Lenovo executive and pioneer in her own right. O’Sullivan also worked for NASA as an IBM employee at the same time Ride was preparing to head into space. They never met, although they now laugh and say they were in the same buildings. O’Sullivan, a rarity as a female engineer in the 1980s, went on to become one of the early team members that helped commercialize and develop a novelty IBM called the “personal computer.”

Ride, an entrepreneur with a company called Sally Ride Science, told 36 girls selected from around North Carolina and another 80 or so daughters of Lenovo employees in the audience as well as those tuning in via the Web to think about engineering as an exciting career choice.

“There are just so many opportunities for you,” Ride said. She is determined to “put female faces on these careers,” and puts on “science fairs” to help draw girls to science. In fact, Ride recently hosted a fair at Meredith College in Raleigh. Ride wants to “crush” stereotypes about women in engineering and other scientific fields.

Time after time during her presentation, Ride used photographs from space to try to evoke excitement and interest in the crowd.

“I still can’t believe my dream came true for me,” she added. “It’s up to all of us to help young women reach for the stars.”