US: US shuttle Discovery closes in on space station
By Jean-Louis SantiniSun Aug 30 16:41:56 EST 2009
Sun Aug 30 06:41:56 UTC 2009
CAPE CANAVERAL, Florida, Aug 30 AFP - The US shuttle Discovery chased the International Space Station (ISS) on Sunday to deliver a treadmill, food and a laboratory freezer to the orbiting outpost.
As the shuttle raced towards the ISS, the astronauts conducted a routine inspection of Discovery's heat shield by manoeuvring a sensor on a robotic arm to look for possible damage.
The crew also checked the spacesuits that will be used for the three spacewalks scheduled for the mission aboard the ISS.
The shuttle has begun its latest journey with the failure of one of two small steering jets that flank the orbiter nose after a leak, but NASA said the loss would have no impact on Discovery's flight or return to earth.
The astronauts will close a manifold to isolate both jets and disable them from use for the remainder of the mission, said the National Aeronautics and Space Administration (NASA).
Discovery, and its crew of seven astronauts including one Swede is delivering equipment for a new bedroom, a treadmill, a freezer, food and other supplies.
It will also be dropping off the newest member of the ISS team, US astronaut Nicole Stott, who will be taking over from engineer and fellow American Tim Kopra.
Kopra has been aboard the orbiting laboratory since July and is returning to earth with Discovery.
The shuttle is scheduled to link up with the station at 8.03pm central daylight time (1103 AEST on Monday), NASA said on its website.
Discovery blasted off from Cape Canaveral, Florida, late on Friday after its launch was delayed three times.
A first attempt last Tuesday was cancelled shortly before liftoff when weather conditions were deemed too dangerous, and two subsequent attempts were thwarted by problems with a liquid hydrogen fill-and-drain valve.
NASA engineers eventually fixed the problem after discovering that the problem was caused by false instrument readings.
The crew will be delivering to the station 6.8 tonnes of cargo transported in a pressurised module called Leonardo that was built by the Italian space agency.
Two astronauts from the team are scheduled to conduct three spacewalks of six-and-a-half hours each during the 13-day mission, the fourth of five planned for the shuttle this year. The last is scheduled for November.
One of the key goals of the spacewalks is the replacement of an old liquid ammonia tank, which will be substituted with a new 800kg replacement. The substance is used as a coolant.
The astronauts will also be retrieving experiment equipment from the exterior of the ISS and returning it to earth for processing.
The freezer being delivered will store samples of blood, urine and other materials that will eventually be taken back to earth for study on the effects of zero gravity.
The Colbert treadmill, named after popular US comedy talk-show host Stephen Colbert, will be the second aboard the ISS. Exercise is key for astronauts spending long periods of time in space, where zero gravity can result in muscle atrophy.
The mission will be the 128th for the space shuttle program, and the 30th mission to the ISS.
Once the Discovery mission is complete, just six more shuttle flights remain before NASA's three shuttles are retired in September 2010.
The International Space Station is a project jointly run by 16 countries at a cost of $US100 billion ($A119.32 billion), largely financed by the United States.
