Space Shuttle Endeavour

Space Shuttle Endeavour is one of the three currently operational Space Shuttle orbiters in the Space Shuttle fleet of NASA, the space agency of the United States. (The other two are Space Shuttle Discovery and Space Shuttle Atlantis.) Endeavour was the fifth and final NASA space shuttle to be built.

Current status
Endeavour is currently in the Orbiter Processing Facility being prepared for its next space shuttle mission, STS-127, currently slated to launch as early as May 15, 2009 from Launch Pad 39A at the Kennedy Space Center.

History
The United States Congress authorized the construction of Endeavour in 1987 to replace Space Shuttle Challenger, which was lost in an accident in 1986. Structural spares from the construction of Space Shuttle Discovery and Space Shuttle Atlantis, two of the three remaining operating shuttles at the time, were used in its assembly. The decision to build Endeavour was favored over refitting Space Shuttle Enterprise on cost grounds.

Endeavour was named through a national competition involving students in elementary and secondary schools. Entries included an essay about the name, the story behind it and why it was appropriate for a NASA shuttle, and the project that supported the name. Endeavour was the most popular entry, accounting for almost one-third of the state-level winners

For example, Utah's state level winner, Nolan Butcher, a sixth grade student from Nibley Park Elementary school located in Salt Lake City Utah, selected Endeavour because some definitions of the word mean to be bold and put forth great effort. The national winners were Senatobia Middle School in Senatobia, Miss., in the elementary division and Tallulah Falls School in Tallulah Falls, Ga., in the upper school division. The national winners were selected based on the quality of the project submitted with their entries. They were honored at several ceremonies in Washington, D.C., including a White House ceremony where then-President George H.W. Bush presented awards to each school The orbiter is named after HM Bark Endeavour, the ship commanded by 18th century explorer James Cook; the name also honored Endeavour, the Apollo Command/Service Module of Apollo 15. This is why the name is spelled in the British English manner, rather than the American English spelling of "Endeavor." This has caused confusion, most notably when NASA themselves misspelled a sign on the launch pad in 2007. {{Cite web|url=http://www.local6.com/technology/13675075/detail.html|title=Shuttle's Name Misspelled On NASA Launch Pad Sign

Endeavour was delivered by Rockwell International in May 1991 and first launched a year later, in May 1992, on STS-49. Rockwell International claimed that it had made no profit on Space Shuttle Endeavour, despite it costing $2.2 billion USD. On its first mission, it captured and redeployed the stranded Intelsat VI communications satellite.

In 1993, it made the first service mission to the Hubble Space Telescope. Endeavour was withdrawn from service for eight months in 1997 for a retrofit, including installation of a new airlock. In December 1998, it delivered the Unity Module to the International Space Station. Endeavour completed its latest Orbiter Major Modification period, which began in December 2003, and ended on Thursday, October 6, 2005. During this time, the Orbiter received major hardware upgrades, including a new, multi-functional, electronic display system, often referred to as glass cockpit, and an advanced Global Positioning System receiver, along with safety upgrades Columbia Accident Investigation Board by the Columbia Accident Investigation Board (CAIB) for Shuttle return to flight after the Space Shuttle Columbia disaster of sister-ship Columbia during re-entry on February 1, 2003.

The STS-118 mission, the first for Endeavour following a lengthy refit, included astronaut Barbara Morgan, formerly assigned to the Educator Astronaut program, but now a full member of the Astronaut Corps, as part of the crew. Morgan was the backup for Christa McAuliffe on the ill-fated STS-51-L mission.

Upgrades and features
Endeavour features new hardware designed to improve and expand orbiter capabilities. Most of this equipment was later incorporated into the other two orbiters during out-of-service major inspection and modification programs. Endeavour's upgrades include:
 * A 40-foot (12 m) diameter drag chute that is expected to reduce the orbiter's rollout distance by 1,000 to 2,000 feet (300 to 600 m).
 * The plumbing and electrical connections needed for Extended Duration Orbiter (EDO) modifications to allow up to 28-day missions (although a 28-day mission has never yet been attempted; the current record is 17 days, which was set by Columbia).
 * Updated avionics systems that include advanced general purpose computers, improved inertial measurement units and tactical air navigation systems, enhanced master events controllers and multiplexer-demultiplexers, a solid-state star tracker and improved nose wheel steering mechanisms.
 * An improved version of the Auxiliary Power Units (APUs) that provide power to operate the Shuttle's hydraulic systems.

Modifications resulting from a 2005-2006 refit of Endeavour include:


 * The Station-to-Shuttle Power Transfer System (SSPTS), which converts 8 kilowatts of DC power from the ISS main voltage of 120VDC to the orbiter bus voltage of 28VDC. This upgrade will allow Endeavour to remain on-orbit while docked at ISS for an additional 3- to 4-day duration. The corresponding power equipment was added to the ISS during the STS-116 station assembly mission, and Endeavour flew with SSPTS capability during STS-118.

Decommissioning of Space Shuttle Endeavour
According to NASA, Space Shuttle Endeavour will be decommissioned in 2010, after 18 years of service, along with Discovery and Atlantis. NASA expects to have the Orion spacecraft ready no later than 2014. Based on the current (as of August 2007) consolidated launch manifest, Endeavour may be the last Orbiter to fly, contingent on the optional STS-133 mission to the International Space Station, which will carry the final components in the ISS assembly sequence, the EXPRESS Logistics Carrier ELC5 and ELC1, to orbit.