[an error occurred while processing this directive]
BBC News
watch One-Minute World News
Last Updated: Monday, 6 August 2007, 11:54 GMT 12:54 UK
Shuttle set for Wednesday launch
Space shuttle Endeavour on launch pad, Nasa

Nasa has started the countdown clock ticking for the launch of its space shuttle Endeavour.

The shuttle is scheduled to blast off at 2336 BST (1836 EDT) on Wednesday to begin its 11-14 day assembly mission to the International Space Station (ISS).

Currently, the weather forecast looks promising for a launch on Wednesday, the US space agency says.

There is only a 30% chance that showers or clouds could prevent lift-off from Kennedy Space Center in Florida.

This prediction remains the same if Nasa has to order a 24-hour flight delay.

"The team is ready. Endeavour is ready," Nasa test director Stephen Payne said on Sunday.

Nasa officials must be hoping that a successful launch will divert attention away from recent reports of astronauts being drunk on duty and the sabotage of a non-critical computer.

Leak repair

Last week, the space agency replaced a leaky valve in Endeavour's cabin with one taken from the shuttle Atlantis.

Engineers discovered that air had been escaping from the removed valve because of a small piece of debris on its seal, Mr Payne said. The valve itself turned out to be fine.

Barbara Morgan, Getty Images
Ms Morgan has been waiting to go into space for years
Because of the extra work to replace and test the new valve, officials delayed the flight by one day, to Wednesday.

This mission marks the first flight for Endeavour since 2002.

Flying on the shuttle is schoolteacher-turned-astronaut Barbara Morgan.

Ms Morgan, 55, originally trained at Nasa as a back-up for Christa McAuliffe, who was selected for Nasa's Teacher in Space programme, announced by President Reagan in the 1980s.

McAuliffe and six other astronauts were killed in 1986 aboard the shuttle Challenger, when a leaky booster rocket triggered an explosion 73 seconds into launch.

Schools project

After the incident, Nasa asked Ms Morgan to stay on as its Teacher in Space representative and pledged a shuttle flight to fulfil McAuliffe's educational agenda.

But then the agency also banned civilians from flying in its spacecraft, so Ms Morgan had to become a fully trained astronaut, joining Nasa's corps in 1998.

She will operate a robot arm in space and, if time permits, speak with school children at locations around the US via a link-up.

Nasa hopes to stretch the mission from 11 days to 14 days, with help from a new system fitted aboard the shuttle.

The system will convert and transfer power from the station to the shuttle, allowing the shuttle to remain docked longer than ever before.

Endeavour's seven crew have been continuing with final launch preparations.

On Sunday morning, Commander Scott Kelly and pilot Charlie Hobaugh made several practice landings in the shuttle training aircraft, a modified Gulfstream II jet that mimics the flying characteristics of Nasa's orbiter.

Weightlessness in Nasa training exercise

Nasa to replace Endeavour valve
02 Aug 07 |  Science/Nature
Nasa astronauts 'drunk on duty'
27 Jul 07 |  Americas
Nasa scandals overshadow launch
27 Jul 07 |  Science/Nature
Charged Nasa woman 'had no nappy'
29 Jun 07 |  Americas

The BBC is not responsible for the content of external internet sites

Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit


Americas Africa Europe Middle East South Asia Asia Pacific