Thunder Pig

STS-135 (ISS assembly flight ULF7)^[5] is the final planned mission of the American Space Shuttle.^[6][7] It will use the hardware originally processed for theSTS-335 contingency mission, as the Launch On Need (LON) rescue mission designated to support STS-134 was not ultimately needed. The mission is scheduled to launch on 8 July and land on 20 July 2011.

Although the mission was authorized, it initially had no appropriation in the NASA budget, raising questions about whether the mission would fly at all. On 20 January 2011, program managers changed STS-335 to STS-135 on the flight manifest. This allowed for training and other mission specific preparations.^[8] On 13 February 2011, program managers told their workforce that STS-135 would fly “regardless” of the funding situation via a continuing resolution.^[9] Until this point, there had been no official references to the STS-135 mission in NASA official documentation for the general public.^{[10][11][12][13]}

During an address at the Marshall Space Flight Center on 16 November 2010, NASA administrator Charles Bolden said that the agency needed to fly STS-135 to the station in 2011, due to likely delays in the development of commercial rockets and spacecraft designed to transport cargo to the ISS. "We are hoping to fly a third shuttle mission (in addition to STS-133 and STS-134) in June 2011, what everybody calls the launch-on-need mission ... and that's really needed to [buy down] the risk for the development time for commercial cargo," Bolden said.^[14]

Space Shuttle Atlantis is to fly the 12-day mission. Atlantis will carry the STS-335 four-person crew (the smallest of any shuttle mission since April 1983'sSTS-6). The mission's primary cargo will be the Multi-Purpose Logistics Module (MPLM) Raffaello and a Lightweight Multi-Purpose Carrier (LMC). The mission is included in NASA's 2011 authorization,^[15] signed into law on 11 October 2010, but funding remained dependent on a subsequent appropriation bill. United Space Alliance signed a contract extension for this mission, along with STS-134; the contract contained six one-month options with NASA in order to support continuing operations. All STS-135 crew members were custom-fitted for a Russian Sokol space suit and molded Soyuz seat liner, should they be forced to return to Earth via a Soyuz capsule in the event that the shuttle is deemed unable to make a safe reentry.^[16]