Timeline of Space Shuttle Orbiters - Fleet

Fleet

Individual Space Shuttle orbiters were named in honor of antique sailing ships of the navies of the world, and they are also numbered using the NASA Orbiter Vehicle Designation system. Three of the names had also been borne by Apollo spacecraft in 1969–1972: Apollo 11 command module Columbia, Apollo 15 command module Endeavour, and Apollo 17 lunar module Challenger.

While all of the Orbiters are externally practically identical, they have minor differences in their interiors. New equipment for the Orbiters was installed in the same order that they underwent maintenance work, and the newer Orbiters were constructed by Rockwell International, under NASA supervision, with some more advanced, lighter in weight, structural elements. Thus, the newer Orbiters, such as the Atlantis and the Endeavour, had slightly more cargo capacity than the others.

The Space Shuttle orbiters were assembled at Rockwell's assembly facility in Palmdale, California, at the federally owned Plant 42 complex.

• The Inspiration was an actual full-scale mock-up originally built and used to test clearance and various ground operations; currently displayed at Columbia Memorial Space Science Learning Center in Downey, California.
• The Pathfinder was an actual full-scale mock-up originally built and used to test clearance and various ground operations; currently displayed at Space Camp in Huntsville, Alabama.
• The Enterprise was a prototype designed to test Space Shuttle behavior in atmospheric flight. Currently located at the Intrepid Sea, Air & Space Museum

• The Columbia first launched on April 12, 1981. On February 1, 2003, the Columbia burned and disintegrated during its re-entry during its 28th spaceflight.
• The Challenger first launched on April 4, 1983. On January 28, 1986 it disintegrated 73 seconds after launch on its 10th mission.
• The Discovery first launched on August 30, 1984. It flew 39 missions, and was NASA's Return to Flight vehicle, following the accidental destruction of the Challenger. The Discovery completed its last mission, STS-133, in March 2011. It is currently on display at the Smithsonian's National Air and Space Museum Steven F. Udvar-Hazy Center near Dulles International Airport.
• The Atlantis first launched on October 3, 1985. It flew 33 spaceflights including the final space shuttle mission, STS-135, in July 2011.
• The Endeavour first launched on May 7, 1992. It flew 25 spaceflights, the final being STS-134, launched May 16, 2011.

In addition to the test articles and orbiters produced for use in the Shuttle program, there are also various mock-up replicas on display throughout the world:

• Space Shuttle Explorer (honorary number OV-100), a full-scale replica of the entire orbiter at the Johnson Space Center's visitor facility in Houston, Texas
• Space Shuttle Adventure, a full-scale replica of an orbiter mid-deck and flight deck at Space Center Houston
• Space Shuttle America, a full-scale replica of a space shuttle for a theme park attraction since disassembled and removed
• Space Shuttle Resolution, a full-scale replica of a space shuttle crew-compartment, originally built to house a flight simulator but later used by Kennedy Space Center firefighters to practice rescue techniques.