STS-127 (ISS assembly flight 2J/A) was a NASA Space Shuttle mission to the International Space Station (ISS). It was the twenty-third flight of Space Shuttle Endeavour. The primary purpose of the STS-127 mission was to deliver and install the final two components of the Japanese Experiment Module: the Exposed Facility (JEM EF), and the Exposed Section of the Experiment Logistics Module (ELM-ES). When Endeavour docked with the ISS on this mission in July 2009, it set a record for the most humans in space at the same time in the same vehicle, the first time thirteen people have been at the station at the same time. Together they represented all ISS program partners and tied the general record of thirteen people in space with the first such occurrence of 1995.
The first launch attempt, on June 13, 2009, was scrubbed due to a gaseous hydrogen leak observed during tanking. The Ground Umbilical Carrier Plate (GUCP) on the external fuel tank experienced a potentially hazardous hydrogen gas leak similar to the fault that delayed the Space Shuttle Discovery mission STS-119 in March 2009. Since a launch date of June 18, 2009, would have conflicted with the launch of the Lunar Reconnaissance Orbiter (LRO)/Lunar Crater Observation and Sensing Satellite (LCROSS), NASA managers discussed the scheduling conflict with both the Lunar Reconnaissance Orbiter project and the Air Force Eastern Range, which provides tracking support for rockets launched from Florida. A decision was made to allow the shuttle to attempt a second launch on June 17, 2009, allowing LRO to launch on June 18, 2009.
