Tuesday, August 25, 2009

NASA begins filling shuttle Discovery's external fuel tank

NASA on Monday began filling the external fuel tank of the shuttle Discovery, one day before it blasts off toward the International Space Station carrying a crew of seven astronauts. As space officials prepared for Tuesday's launch, they said they saw nothing worrisome at this time that would lead to a delay.

"Everything looks normal. There is no technical issue to report," said NASA spokesman George Diller. Mission officials said there is an 80 percent chance of launch-friendly meteorological conditions, although there is a slight risk of thunderstorms and lightning within an eight-kilometer (five-mile) area of the launchpad.

Discovery's liftoff is set for 0136 am (0536 GMT) on Tuesday from Kennedy Space Center in Cape Canaveral, Florida. The task of filling the enormous reservoir, which got underway about 10 minutes late, was to be completed at 7:15 pm (23H15 GMT), US space officials said.

The space vehicle's external fuel tank was being filled with nearly two million liters of liquid hydrogen and oxygen. Discovery is to deliver 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.

Stott will be taking over from engineer and fellow American Tim Kopra, who has been aboard the ISS since July and is returning to Earth with the Discovery. The Discovery crew, led by astronaut Rick Sturckow, will be delivering 6.8 tonnes of cargo transported in a pressurized 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, which is the fourth of five planned for the shuttle this year. The last is scheduled for November.

One of the key goals of the space walks is the replacement of an old liquid ammonia tank, which will be substituted with a new 800 kilogram replacement brought from Earth aboard the Discovery. The substance is used as a coolant.

The astronauts will also be retrieving experiment equipment from the outside of the ISS and returning it to Earth for processing. The new freezer 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 talkshow 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.

Among the seven-member crew is veteran European astronaut Christer Fugglesang, 52, of Sweden. The shuttle flight also is the first with two Hispanic astronauts: veteran mission specialist John "Danny" Olivas, 44, of El Paso, Texas, and rookie Jose Hernandez, 47, of Stockton, California.

Hernandez will provide bilingual Twitter updates from space, via Twitter.com. 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.

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