The space shuttle Discovery left Florida's Kennedy Space Center for the last time on April 17, hitching a ride aboard a modified jumbo jet and heading to Washington to become a Smithsonian museum exhibit.

Discovery — the fleet leader with 39 orbital missions — is the first of the three retired space shuttles to head to a museum. Endeavour will head to Los Angeles in the fall of 2012. Atlantis will remain at Kennedy.

Nearly 2,000 people — former shuttle workers, VIPs, tourists and journalists — gathered along the old shuttle landing strip to see Discovery off at daybreak. A cheer went up as the plane taxied down the runway and soared into a clear sky.

The plane and shuttle headed south and made a last pass over the beaches of Cape Canaveral, where thousands jammed the shore for a glimpse of Discovery. The flight returned to the space centre in a final salute before heading for Washington.

Discovery's landmark moments

Discovery was a workhorse of NASA's shuttle fleet for nearly three decades.

Discovery by the numbers

  • First launch: Aug. 30, 1984
  • Kilometres flown: More than 238 million
  • Number of orbital missions: 39
  • Missions to the International Space Station: 13
  • Missions to the Russian Mir space station: 2
  • Total number of days spent in orbit: 365
  • Longest flight: 10 million km (34th flight, Oct. 23-Nov. 7, 2007)
  • Shortest flight: 1.99 million km (3rd flight Jan. 24-27, 1985)
  • Most missions in a year: Four in 1985. No other shuttle flew that many times in a 365-day period.
  • Years without Discovery missions: 1986, 1987, 1996, 2003, 2004
  • Final launch: Feb. 24, 2011

(Source: NASA)

Construction of Discovery— or Orbiter Vehicle 103 — began on Aug. 27, 1979, and took four years. When it was launched for the first time on Aug. 29, 1984, it became NASA's third operational orbiter.

Since then, Discovery has travelled more than 238 million kilometres, spent more than a year in orbit and carried more than 250 astronauts into space. It has docked once with Russia's MIR space station (it visited the station a second time but didn't dock), and 13 times with the International Space Station (ISS).

Discovery has carried satellites, ferried modules and crew to the ISS, and provided the setting for countless scientific experiments.

On its second mission, Discovery became the first spacecraft to retrieve a satellite and bring it back to Earth. Crew members used jetpacks to manoeuvre outside the craft and reach two malfunctioning satellites, easing them into Discovery's payload bay so they could be returned to Earth and repaired.

There have been several remarkable achievements on Discovery flights. Among them was the return of John Glenn into space in October 1998. The 77-year-old Glenn became the oldest human to orbit the Earth. It was Glenn's second trip into space after he became the first American to orbit the Earth in 1962. Glenn's shuttle mission was also used for a host of experiments that studied aging.

Discovery's cargo has included the Hubble Space Telescope, which was deployed in April 1990. From its unique vantage point, Hubble has seen deeper in space and in time than any previous telescope.

In February 1994, a Discovery mission included Sergei Krikalev of Russia, who became the first cosmonaut to fly on an American spacecraft.

The Discovery mission that launched in October 2000 was the 100th mission of the space shuttle program. The 12-day mission installed a shuttle docking port on the ISS and the first piece of the station's exterior truss structure. That set the stage for the arrival of the space station's first residents a few weeks later.

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Discovery stands ready after arriving at launch pad 39A at the Kennedy Space Center in Cape Canaveral, Fla., on Sept. 21, 2010. ((John Raoux/Associated Press))

Twice, Discovery was the first shuttle to return to service after accidents grounded the shuttle program. Challenger broke apart 73 seconds after liftoff on Jan. 28, 1986, killing its seven-member crew, including Christa McAuliffe, the first civilian in the U.S. space program. The shuttle program was suspended for more than two years while modifications were made to the spacecraft. Discovery returned to service on Sept. 29, 1988, for a four-day mission.

Discovery's flight in July 2005 was also the first shuttle mission after the Feb. 1, 2003, Columbia disaster. That shuttle disintegrated as it re-entered Earth's atmosphere, killing seven astronauts.

Last trip into space

Discovery's last trip into space marked the beginning of the winding-down of NASA's shuttle program. Like the shuttle program itself, that last mission faced numerous problems.

Liftoff was orginally scheduled for Nov. 5, 2010, but had to be scrapped after a chunk of insulating foam from the external fuel tank broke away during fueling. Further investigation revealed that two U-shaped support beams, known as stringers, had cracked. A crewmember was also injured in a cycling accident weeks before the launch, and had to be replaced.

Discovery lifted off from Kennedy Space Center in Florida for its final trip into space, mission STS-133, at 4:53 p.m. ET on Feb. 24, 2011. The takeoff attracted tens of thousands of spectators in Cape Canaveral. By 5:02 p.m., NASA reported that the shuttle's main engines were off and the shuttle was in space. 

The 12-day mission to the International Space Station was the 39th and final flight for a spacecraft that had been in service for almost 30 years.

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Discovery crew members, from left, mission specialists Nicole Stott, Michael Barratt, Steve Bowen, Alvin Drew, Pilot Eric Boe, and Commander Steve Lindsey at Kennedy Space Center in Cape Canaveral, Fla., on Feb. 20. Bowen replaced Tim Kopra, who was injured in a bicycle accident on Jan. 15. ((Chris O'Meara/Associated Press))

Mission STS-133 was crewed by Eric Boe, Steve Lindsay, Michael Barratt, Alvin Drew, Steve Bowen and Nicole Stott. Bowen replaced Tim Kopra, who was unable to fly on the mission after being injured in a bicycle accident on Jan. 15. 

During two spacewalks, Discovery astronauts performed critical maintenance work on the outside of the space station. NASA says the shuttle spent eight days, 16 hours and 46 minutes attached to the orbiting laboratory on its last mission.

No Canadian astronauts were on Discovery's last flight, but several Canadian experiments made the trip:

  • Hypersole, which looked at how the skin's sensitivity changes before and after space flight. By testing the soles of astronauts' feet during Discovery's mission and two other shuttle flights, human health researcher Leah Bent, of the University of Guelph in Ontario, hopes to learn how changes in skin sensitivity are related to balance control. Among the elderly, a loss of skin sensitivity is linked to a loss of balance control and a greater incidence of falls.
  • APEX-CSA2, which involved growing white spruce seedlings for 30 days in space. The seedlings were sent up on Discovery's April 2010 flight. They returned, harvested and frozen, on Discovery's final flight so their DNA could be analyzed by the team of Jean Beaulieu at Natural Resource Canada's Canadian Wood Fibre Centre in Quebec City.
  • VASCULAR, a study of how the structure of blood vessels changes on long space flights, similar to how they change as people age. Discovery carried blood samples back to Earth for analysis by Richard Hughson and his team at the University of Waterloo in Ontario.

On its final space flight, Discovery delivered a section of the U.S. segment of the ISS, the Leonardo Permanent Multipurpose Module, as well as the first humanoid robot to fly in space, Robonaut2. The new module is a storeroom and added to the station's research space. Robonaut2 is designed to use space tools and work in similar environments as astronauts.

Discovery landed safely at Kennedy Space Center at the end of its final mission, touching down at 11:57 a.m. ET on March 9, 2011. The mission took Discovery over the mark of 365 days of actual time in orbit over its operational life.

"The end of a historic journey," said mission control as the shuttle touched down in Florida. "To the ship that has led the way time and time again, we say farewell Discovery."

With files from Associated Press