Female space pioneer to quit

Ms Collins, 49, said she wanted to spend more time with her family and pursue other interests. Last July she added to her string of firsts by leading NASA's harrowing first flight in space since the Columbia disaster in 2003.

The mission required Ms Collins to perform a series of unprecedented twist-and-flip manoeuvres so the shuttle's belly could be photographed for damage.

"Eileen is a living, breathing example of the best our nation has to offer," said NASA administrator Michael Griffin. "She is, of course, a brave, superb pilot and a magnificent commander."

Qualifying as an astronaut in 1990, she became the first female pilot on a space shuttle with the flight of Discovery in 1995, the first mission to rendezvous with the Russian space station, Mir.

She also flew on Atlantis in 1997 and became the first female commander on the 1999 Columbia flight.

"I can honestly say that in my job day to day, I'm not really aware that there's any difference between male and female crew members," Ms Collins said in an interview last year. "It may be cool to the rest of the world that a woman is the commander of this flight. I think that's great."

A native of Elmira, in New York, Ms Collins studied mathematics and economics at Syracuse University and received masters degrees from Stanford and Webster universities.

She was selected as an astronaut while attending the air force test pilot school at Edwards air force base in California. She had been a mathematics professor and pilot instructor at the US Air Force Academy and a pilot instructor at Vance air force base in Oklahoma. She retired from the air force in 2005.

She began her NASA career working in engineering support for the space shuttle orbiters before joining the astronaut team that inspects the orbiters before launches. She also worked in mission control as a communicator with in-flight shuttle crews.

During her NASA career, she logged more than 872 hours in space.