Here's a look at what you need to know about NASA's Space Shuttle Program which ended in 2011 after 135 missions.
Facts: The space shuttle is the "world's first reusable spacecraft," launching like a rocket, orbiting like a spacecraft, and landing like a plane.
Space shuttles could carry satellites, space probes, and other cargo into orbit around Earth on both commercial and non-commercial missions.
The space shuttle system was made up of three components: - Two solid rocket boosters. They provided 80% of the launch thrust. - The external tank, which provided fuel to the space shuttle main engines during launch. - The orbiter. It acted as the crew's home during the flight.
All of the components were reused except for the external fuel tank. It burned up in the atmosphere after launch.
Crews ranged in size from five to seven people. Over 600 crewmembers flew on shuttle missions.
The space shuttle program sent over 3 million pounds of cargo into space.
The longest any shuttle stayed in orbit was 17.5 days, in November 1996.
The space shuttle was 184 feet long. The orbiter was 122 feet long.
The liftoff weight of the space shuttle was 4.5 million pounds.
There were five orbiters in the shuttle program's history: Atlantis, Challenger, Columbia, Discovery and Endeavour.
The space shuttles Discovery, Atlantis, and Endeavour were each designed to fly 100 missions, though altogether they flew much fewer than that.
Timeline: January 5, 1972 - President Richard Nixon announces the intent to develop the first space shuttle for travel into space.
1970s - The orbiter Enterprise is used for tests but never flies in space.
March 24, 1979 - The orbiter Columbia is delivered to the Kennedy Space Center.
April 12, 1981 - The first space shuttle (STS-1) is launched. The Columbia is the first space shuttle to orbit the earth.
July 5, 1982 - The orbiter Challenger is delivered to the Kennedy Space Center.
November 9, 1983 - Discovery is delivered to the Kennedy Space Center.
April 13, 1985 - Atlantis is delivered to the Kennedy Space Center.
January 28, 1986 - Challenger explodes minutes after launch due to faulty O-rings in the shuttle's rocket booster. Flights do not resume for another two years.
February 1, 2003 - The Space Shuttle Columbia explodes over Texas after a large piece of foam rips off during Columbia's launch and gouges a hole in the left wing in the shuttle. Atmospheric gases burn the wing during re-entry, and the orbiter is destroyed.
July 26, 2005 - The Discovery is launched. On July 27, NASA grounds its space shuttles until engineers solve the recurring problem of falling debris, pieces of which tore away from the shuttle Discovery shortly after the blastoff.
August 9, 2005 - Discovery lands safely at Edwards AFB in California.
July 3, 2006 - Workers find a crack in the foam insulation covering a bracket that connects the liquid oxygen feed line to shuttle Discovery's external fuel tank. The crack is four to five inches long, and one eighth of an inch to a quarter-inch wide.
July 4, 2006 - The Space Shuttle Discovery is successfully launched.