Space Shuttle gliding and landing; it was originally intended to be outfitted for orbital operations after the test program, but it was found more economical to upgrade the structural test article STA-099 into orbiter "Challenger" (OV-099). An additional test article, dubbed "Pathfinder" (OV-098), was built for form and fit tests, and is on display at the Alabama Space and Rocket Center in Huntsville, AL. "Challenger" disintegrated 73 seconds after launch in 1986, and "Endeavour" was built as a replacement from structural spare components. Building "Endeavour" cost about US$1.7 billion. "Columbia" broke apart over Texas during re-entry in 2003. A Space Shuttle launch
Space Shuttle Atlantis U.S. manned space flight; first U.S. Shuttle-Russian Space Station Mir docking and joint on-orbit operations; and first on-orbit changeout of shuttle crew. When linked, "Atlantis" and "Mir" together formed the largest spacecraft in orbit at the time. Shuttle "Atlantis" also delivered several vital components for the construction of the International Space Station (ISS). During the February 2001 mission STS-98 to the ISS, "Atlantis" delivered the Destiny Module, the primary operating facility for U.S. research payloads aboard the ISS. The five hour 25 minute third spacewalk performed by astronauts Robert Curbeam and Thomas Jones during STS-98 marked NASA's 100th extra vehicular