Friday, July 23, 1999 Published at 04:21 GMT 05:21 UK
Third time lucky for Columbia?
Lightning over Cape Canaveral foiled Wednesday's launch
The space shuttle Columbia is being prepared at the Kennedy Space Center in Florida for an historic mission that has already suffered two last-minute postponements.
And the pressure is on for today's launch, scheduled for 0031 EST (0431 GMT).
If it fails, Columbia will be grounded until August 18, according to Nasa flight director Donald McMonagle.
Nine minutes before launch-time, Mission Control said: "There are no technical issues and everything is looking very good."
The deployment of the shuttle's cargo, the Chandra X-ray observatory, is almost one year behind schedule.
Thunderstorms near the launch site prompted Nasa officials to cancel Wednesday's scheduled launch.
Mission Control explained to the crew that lightning strikes were reported within 10 miles of the launch site.
"It's a flight no-go," the launch controller, Ralph Roe, told Commander Eileen Collins. "We'll give it another try on another day."
The countdown was stopped five minutes from ignition as controllers waited for the storm to abate - and the launch "window" was extended by 10 minutes - but to no avail.
Try and try again
The mission had already suffered at least 10 delays since its original lift-off date of November 1998. These were caused by problems with both the shuttle engines and its cargo, the Chandra X-ray observatory.
The Chandra Observatory will study X-ray emissions from distant stars and galaxies that are largely undetectable from Earth because of atmospheric absorption.
Scientists hope the telescope will, for example, help them estimate the so-called "dark matter" that scientists know exists but cannot be seen.
The first launch attempt was dramatically aborted on Tuesday just six seconds before blast off, when sensors reported a possible hydrogen gas leak in an engine compartment. It turned out to be a false alarm.
The shuttle's three main engines fire several seconds before lift-off as they build up power. If they had fired, Columbia would have had to be refitted with new engines, delaying the mission by up to a year.
The launch had been scheduled to coincide with the 30th anniversary of the first moonwalk on 20 July.
First woman commander
Colonel Collins - who piloted the shuttle in February 1995 - admits being the first woman commander does add extra pressure but says: "The extra pressure doesn't bother me - I find that I can still do my job effectively."
"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," she says.
Nasa's head, Dan Goldin, obviously agrees: "Eileen Collins is the commander. So what's the news?" he said.
Outside Nasa, however, there has been great interest in her role, particularly in how she combines being an astronaut and a mother to her three-year-old daughter, Bridget. Colonel Collins says both jobs are equally difficult, yet equally rewarding.