Monday, July 19, 1999 Published at 14:58 GMT 15:58 UK
Countdown for shuttle commander
The former test pilot has clocked up 419 hours in space
The first space shuttle mission to be commanded by a woman will take off at 0436 GMT (0536 BST) on Tuesday, the 30th anniversary of the first Moon landing.
She will also be responsible for one of the most expensive shuttle payloads ever - Nasa's $1.5bn Chandra X-ray Observatory, which is on a scientific par with the Hubble Space Telescope. The total price tag for the entire Chandra project, from development through five years of orbital operation will be $2.8bn.
The 25-tonne telescope is also the heaviest cargo ever lifted by the space shuttle.
She does not see it as a giant leap for womankind: "It's an honour for me to be chosen, but I also see it as an evolutionary process. Eventually, having women in these roles won't be news anymore. It will be expected," she says.
"Inside of Nasa, I'm very accepted and I'm treated very much like the other astronaut Commanders. I really don't notice a difference."
Nasa's head, Daniel Goldin, obviously agrees: "Eileen Collins is the commander. So what's the news?" he said.
Her fellow crew member on Tuesday's mission, Air Force Lieutenant Colonel Catherine Coleman, says the advent of the first woman commander is significant.
Colonel Collins, a former test pilot, began her flying career by taking oddjobs to pay for the flying lessons her family could not afford. She has now logged more than 5,000 hours in 30 types of aircraft and 419 hours in space.
The primary objective of the five-day mission is to deploy the Chandra X-ray Observatory, but there are many more experiments and tests to carry out including:
"Fly cast manoeuvre": This September's shuttle mission will have a 60 metre radar boom deployed when in orbit. Periodic boosting of the engines is required to stop the shuttle falling to Earth but this jolting could damage the boom. So this mission will test whether pulsing the engines with millisecond timing avoids any damage.