Discovery shuttle makes historic last touchdown
The most-travelled of America's space shuttles, Discovery, has brought its remarkable 27-year career to an end.
The orbiter has just landed at the Kennedy Space Center in Florida after a 12-day - and final - mission to the International Space Station (ISS).
Discovery is destined now to go to a museum. Nasa's two other reusable spaceplanes will follow it into retirement in the coming months.
The landing at Kennedy occurred just before midday, local Florida time.
On its final flight, Discovery delivered a new store room and a sophisticated humanoid robot to the ISS.
The ship's crew also performed two spacewalks to carry out maintenance tasks on the exterior of the platform.
The final act in Discovery's career was initiated with a two-minute, 31-second burn from its thrusters.
This dropped the ship out of orbit and into a re-entry path that took it across the Pacific, over Central America and the Gulf, before a last sharp banking manoeuvre and a touchdown on Kennedy's Runway 15 at 1157 and 17 seconds EST (1657:17 GMT).
"Houston, Discovery for the final time - wheels stop," Commander Steve Lindsay radioed to Mission Control in Texas.
"Job well done," was the reply from astronaut Charlie Hobaugh, who was acting as the Capsule Communicator, or Capcom, in Houston. "You were able to take Discovery up to a full 365 days of actual time on orbit. I think you'd call that a fleet leader, and a leader of any manned vehicle for time in orbit."
Already, Nasa is looking forward to the next mission. In just a few hours, shuttle Endeavour will roll out of Kennedy's vast Vehicle Assembly Building to go to the launch pad in preparation for its final voyage into space next month.
The Atlantis orbiter will close the shuttle programme with a flight in June or just beyond.
The plan then is for US astronauts to be transported to the ISS on Russian Soyuz rockets, perhaps until the middle of the decade.
A number of American companies should be in a position by that stage to sell launch services to Nasa on a range of new vehicles.
Such matters, though, are secondary on what is undoubtedly a day of high emotion.
DISCOVERY: FLEET LEADER
- It is named after various historic vessels, including James Cook's 18th Century explorer
- Discovery was the first spacecraft to retrieve a satellite and bring it back to Earth
- It has completed more missions than any other vehicle in the space shuttle fleet
- The shuttle visited both the Russian Mir station and the International Space Station
- It carried the Hubble Space Telescope into orbit and made two servicing missions
- The ship's total in-orbit time: 365 days; Total distance travelled: 238 million km
Eileen Collins was the first woman to pilot a shuttle, and commanded Discovery in 2005 on the "return to flight" mission after the Columbia accident.
"The shuttle-in-general's biggest achievement, I believe, was building the International Space Station, which is pretty much 99% complete - and Discovery was part of doing that," she told BBC News.
"But also Discovery took up the Hubble Space Telescope and also visited the Mir space station, and did many satellite deploys and spacelab missions prior to the space station.
"When you look at the shuttle programme as a whole, we have learned not only to fly space shuttles to low-Earth orbit and re-use them, but we've learned about the environment of space and how to make future spacecraft better through the mistakes that were made in the shuttle programme. So overall I think the shuttle was a huge success."
Endeavour's scheduled lift-off date is 19 April. It will deliver a flagship scientific experiment to the ISS known as the Alpha Magnetic Spectrometer (AMS).
This seven-tonne instrument will sit on the platform's truss, or backbone, to conduct a survey of cosmic rays.
Researchers hope this study will reveal new insights into the make-up and origin of the Universe.
Endeavour will be commanded by astronaut Mark Kelly, whose wife, Congresswoman Gaby Giffords, is still recovering from a bullet wound to the head sustained during an assassination attempt in January.