The US space shuttle Endeavour on Wednesday began the process of leaving orbit ahead of its final landing at Kennedy Space Center in Florida, set for 2:35 am (0635 GMT).

The deorbit burn began on time at 1:29 am (0529 GMT), with shuttle commander Mark Kelly putting on the brakes for two minutes, 38 seconds.

That was just enough time to slow the shuttle to a speed of 320 kilometers per hour (201 miles per hour), allowing it to leave orbit.

As with past shuttle missions, the vessel will have no engine power when it returns to earth, so Kelly will maneuver it so that it glides onto the runway at Kennedy Space Center for a nighttime landing.

The 16-day mission to the International Space Station is the last one for the shuttle Endeavour and the penultimate flight for the 30-year-old US shuttle program, which is to end after Atlantis launches on July 8.

NASA rolls out shuttle Atlantis for final time
Cape Canaveral, Florida (AFP) May 31, 2011 - The US space agency on Tuesday sent its last shuttle, Atlantis, out to the launch pad at Kennedy Space Center so it can prepare for the final launch of the American shuttle program in July.

The shuttle began its trek at 8:00 pm (0000 GMT).

The familiar ritual of rolling a massive shuttle from the Vehicle Assembly Building on a slow journey along a stone-covered crawlerway was a powerful symbol to the thousands of NASA employees who gathered to watch it go.

Atlantis's mission, STS-135, is set to launch on July 8 toward the International Space Station and will be the last journey by a US shuttle before the three-decade program officially draws to a close.

The end of the US shuttle program leaves Russia as the only nation capable of toting astronauts into space until a replacement US vehicle can be built, likely no earlier than 2015.

Shuttle Endeavour prepares for final glide home
Cape Canaveral, Florida (AFP) June 1, 2011 - The space shuttle Endeavour prepared for its final landing early Wednesday and the conclusion of the next to last mission of the 30-year-old US shuttle program.

Endeavour and its crew of six astronauts -- five Americans and one Italian -- were to glide in for a nighttime touchdown at Florida's Kennedy Space Center at 2:35 am (0635 GMT), the US space agency NASA said on Tuesday.

The astronauts are wrapping up STS-134, a 16-day mission to the International Space Station, where they installed a $2 billion physics experiment to probe the origins of the universe and conducted four spacewalks.

The final flight by US shuttle Atlantis is set for July 8, and NASA sent the shuttle from the Vehicle Assembly Building at Kennedy Space Center out to the launch pad one last time at 8:00 pm (0000 GMT).

The event marked a major milestone toward the end of a three-decade program of human space flight and exploration, and it drew thousands of camera-toting employees and media.

Endeavour later began its deorbit by firing its engines about an hour ahead of landing in order to slow the vehicle enough to allow it to fall out of orbit.

After the US shuttle era, the world's astronauts will rely on Russia's space capsules for transit to the orbiting lab at a cost of $51 million per seat until a new US crew vehicle can be built by private enterprise.

NASA has said that a shuttle replacement could emerge sometime between 2015 and 2021.

"There is going to be a period of time when Americans aren't flying on US spacecraft, so that's a challenge," shuttle commander Mark Kelly told US media in a broadcast from space on the last day of Endeavour's mission.

"People leave, you know, engineers and operations people will move on and do other things, so it is the corporate memory that I think I am most worried about," said Kelly, 47.

"But over time, we will get the right mix of people. NASA has an incredible workforce, it is very talented and you know, from the late 1950s to today we have taken on great challenges and we have never failed."

Endeavour is the youngest of the space flying fleet, which also includes Discovery and Atlantis. Discovery retired after returning from its final mission in March.

Two of the original fleet were destroyed by explosions in flight -- Challenger in 1986 and Columbia in 2003. Fourteen astronauts were killed in the disasters.

Endeavour was commissioned in the wake of the Challenger explosion and first flew to space on May 7, 1992. It is now ending its 25th mission, after amassing a total of 122.8 million miles (198 million kilometers), NASA said.

The other shuttle is Enterprise, which was a prototype that never flew in space and has long been on display in a museum outside Washington.

Endeavour's crew includes five Americans and Italian Roberto Vittori of the European Space Agency.

During nearly 11 days at the space station, the crew delivered and installed the Alpha-Magnetic Spectrometer-2, which will be left there to scour the universe for clues about dark matter and antimatter.

They also brought up a logistics carrier with spare parts and performed some maintenance and installation work during four spacewalks, the last to be carried out by an American shuttle crew.

A spacewalk is planned during the Atlantis mission in July but it will be done by the space station crew and not US shuttle astronauts.

After the final shuttle mission, the three spacecraft in the flying fleet and the prototype Enterprise will be sent to different museums across the country.