Endeavour space shuttle set for final touchdown

Endeavour spent just over 11 days attached to the International Space Station

 The US space shuttle Endeavour comes back to Earth on Wednesday for a landing in Florida that will close its 19-year operational career.

The ship has spent the past two weeks at the International Space Station (ISS), where it delivered a $2bn particle physics experiment.
Once on the ground, the orbiter will be decommissioned and prepared for public display in Los Angeles.
This will leave just the Atlantis shuttle to make a final flight in July.
Assuming the weather is favourable, Commander Mark Kelly should be able to glide Endeavour to a touch down at the Kennedy Space Center at 0235 local time (0635 GMT).
The ship will then have spent a cumulative 299 days in orbit, travelling more than 197.6 million km (122.8 million miles) during its 25 missions. Endeavour was first launched on 7 May, 1992, as a replacement for the Challenger vessel which was destroyed on launch six years previously.
Nasa is committed to ending its shuttle programme. The vehicles are too costly to maintain and operate, and the agency believes a more affordable approach to getting astronauts to the ISS can be achieved by contracting out their transport to private companies.

The first of these commercial carriers is expected to enter service sometime in the middle of the decade.

Nasa will concentrate its efforts and resources on a Multi-Purpose Crew Vehicle (MPCV) that can go beyond the space station to destinations such as asteroids.
"Endeavour and the space shuttle have been a workhorse for space exploration, building the entire space station and fixing the Hubble telescope, and doing a whole bunch of interesting tasks," said Endeavour pilot Greg Johnson during an in-flight interview on Monday.
"When the space shuttle retires, we're going to lose a lot of capability of moving large payloads out to space; but then that opens the door for new things that are going to come across the horizon. The children out there ought to be inspired that when they get to go to space they'll probably get to go beyond low-Earth orbit, maybe to the Moon, maybe to Mars or beyond."
Endeavour undocked from the station in the early hours of Monday (GMT). The ship's crew of six had gone to the platform to install the Alpha Magnetic Spectrometer (AMS), a seven-tonne detector designed to survey the blizzard of high-energy particles that are fired at Earth from all corners of the cosmos.
Scientists hope that by characterising these cosmic rays, they can learn more about the origins and make-up of the Universe.
Endeavour had also carried up a tray of critical spare parts for the ISS that included cooling, robotic and communications equipment. The four spacewalks conducted by Endeavour crewmembers Drew Feustel, Mike Fincke and Greg Chamitoff, to carry out routine maintenance on the exterior of the platform, were the last in shuttle history.
And by flying on this mission, Fincke, a colonel in the United States Air Force, has broken the record for the most time spent in space by an American, breaking the 377-day mark set by Peggy Whitson.
Much of the media focus on Endeavour's flight has centred on Mark Kelly. He stood down from the mission briefly in January when his wife, Arizona Congresswoman Gabrielle Giffords, was shot in the head by a gunman at a constituency meeting outside a Tucson supermarket.
She made sufficient progress in her rehabilitation to permit Kelly to re-join the mission, and was even present to see Endeavour's launch from Kennedy on 16 May. But Ms Giffords will not be present at the landing.
Atlantis is scheduled to undertake its final mission on 8 July. The vehicle began making the 5km trip to the launch pad from its assembly hangar late on Tuesday.
Post Source:http://www.bbc.co.uk/news/science-environment-13601008