Space shuttle Atlantis has returned to NASA's Kennedy Space Center after its final planned mission. STS-132 was a delivery and assembly mission to the International Space Station, and saw the addition of the Russian-built Mini Research Module-1 (known also as Rassvet, Russian for "dawn"). The module provides additional storage space and a new docking port for Russia's Soyuz and Progress spacecraft when they resupply the ISS.
The three spacewalks of STS-132 focused mostly on replacing and installing components outside the station, including replacing six batteries on the P6 truss segment, installing a spare Ku-band Space To Ground Antenna (SGANT), and adding parts to the Dextre robotic arm, one of Canada's primary contributions to the ISS.
It is not surprising that a large number of memorabilia was onboard Atlantis for her final flight. Thousands of flags, pins, and patches will be distributed by NASA. One of the more interesting pieces was a 4-inch wood sample supposedly from Sir Isaac Newton's apple tree that inspired his Theory of Gravity.
Atlantis has the Orbiter Vehicle Designation OV-104, and was the last of the original space shuttle fleet to be built. Final assembly was completed on April 10, 1984, but Atlantis didn't take off on its first mission until October of 1985. During its missions, it has docked with Mir; deployed the Compton Gamma Ray Observatory; supported Hubble Space Telescope Servicing Mission 4; and helped install the Destiny Module, Columbus lab, and P3/P4 truss segments on the ISS.
STS-132 was the 132nd shuttle flight, the 32nd flight for Atlantis and the 34th shuttle mission dedicated to station assembly and maintenance.
NASA isn't quite done with Atlantis though. In the wake of the Columbia disaster, the agency has a requirement for a backup shuttle to be ready for a Launch On Need (LON) mission. These missions would be mounted to rescue the crew of a Space Shuttle if their vehicle was damaged and deemed unable to make a successful reentry. The ISS has had sufficient room and supplies to provide shelter for astronauts since STS-125, making LON missions unnecessary. However, the final space shuttle mission (STS-134) requires Atlantis as a LON shuttle. The rescue mission would be designated STS-335 if it is needed.
A remote possibility also exists for one more mission if STS-335 is not needed. Atlantis, its external tank, and two solid rocket boosters will have been prepared to flight-ready status for STS-335. A potential STS-135 mission would use this prepped, readied, and paid-for hardware to fly a full operational mission to the ISS. It would be an extremely simple mission to deliver supplies to the ISS via a Multi-Purpose Logistics Module (MPLM). The large pressurized container is used to transfer cargo to and from the ISS, and will need all the spares it can get before the shuttle fleet is retired. The mission is contingent on Congressional approval, and is not currently planned.
Regardless of the outcome, NASA plans to sell Atlantis to an education institution or museum for $28.8 million.
The stage is now set for the final mission for space shuttle Discovery on STS-133, currently targeted to lift off in September 2010. Discovery's flight will deliver the Leonardo Permanent Multipurpose Module, a rebuilt MPLM, to house experiments and spare parts. STS-133 will also bring critical spare components and a cargo carrier to the station. Robonaut 2, or R2, will be the first human-like robot in space when it flies on Discovery to become a permanent resident of the station.