US shuttle Discovery launch on Monday, one of four final missions

Washington - NASA's Discovery was preparing to launch on Monday one of the remaining four flights of the aging shuttles before year's end.

Discovery is to launch at 1021 GMT Monday from the Cape Canaveral lift-off pad, carrying seven astronauts to the International Space Station (ISS).

After Monday, the breath-taking, chest-rumbling spectacle of a huge shuttle hurtling into the Florida sky will happen only three more times. The goal is to retire the shuttle program by September, but there have been reports that normal delays due to weather and technical problems could put the final flight into early 2011.

The upcoming 13-day shuttle mission offers one more chance for the orbiter to prove its worth as the work-horse of the ISS. Discovery will carry more than 12 tonnes of equipment.

Because much of the load is destined for research, NASA decided to dub the mission "Experiment Express." NASA will load up its Italian- built Leonardo container with a small fitness studio for the station crew, an observation module with cameras and sensors and a ream of scientific instruments for experiments.

Upon arrival at the space station on Wednesday, Leonardo will be removed from Discovery and parked outside for methodical unloading during the nine days Discovery is to spend at the station.

Three spacewalks are planned, each for about 6.5 hours. The tasks include detaching a Japanese experimental apparatus now mounted on the outside frame of the ISS and bringing it inside.

Discovery is to return to earth on April 18.

After the shuttle program ends, the only transport for astronauts to the space station will be Russia's Soyuz capsules. Russia also operates cargo shipments separately from the human transport, but they can carry only a fraction of what the shuttle can.

On Friday, Soyuz launched from the Russian Baikonur cosmodrome in Kazakhstan with one US astronaut and two Russian cosmonauts destined to spend the next six months on the space station. They will dock Sunday with the ISS.

Meanwhile, the shuttle missions are carrying as many heavy replacement parts and instruments as possible to the space station.

The decades-old shuttle spacecraft have been considered a risky proposition for years. Chronic problems with fuel tanks and sensors have often delayed takeoff of the three remaining craft - Atlantis, Discovery and Endeavor. Two shuttles, Colombia and Challenger, exploded during re-entry and takeoff, respectively, killing all astronauts on board.

Source: Earth Times.
Link: http://www.earthtimes.org/articles/show/316933,us-shuttle-discovery-launch-on-monday-one-of-four-final-missions.html.