was a complete success with main gear touchdown occurring at 20:39:08 EDT (00:39:08 UTC March 27, 2008), nose gear touchdown at 20:39:17 EDT (00:39:17 UTC March 27, 2008), and wheels stop at 20:40:41 EDT (00:40:41 UTC March 27, 2008), completing the STS-123 crew's 16 days, 14 hours, 12 minutes, 27 seconds space voyage. The exhaust produced by the Hydrazine Gas Generator APUs on either side of Endeavour''s tail fin created concern among some observers that something was amiss, as it appeared more pronounced than usual in NASA's visual light cameras. However, this exhaust is normal and expected. The three Hydrazine Gas Generator APUs are activated five minutes before the deorbit burn and are running for five minutes after wheels stop. The mono-propellant hydrazine changes phase due to a catalyst and reaches 1,700 °F (927 °C). The hydraulic power is needed for the shuttle's rudder/speed brake, elevons, body flap and landing gear during descent, and for the main engine nozzles' gimballing during ascent. Each of the Solid Rocket Boosters have two similar Hydrazine Gas Generators for their nozzle gimballing. Extra-vehicular activity Five spacewalks took place during the flight. The cumulative time in extra-vehicular activity during the mission was 33 hours and 28 minutes. Wake-up calls NASA began a tradition of playing music to astronauts during the Gemini program, which was first used to wake up a flight crew during Apollo 15. Each track is specially chosen, often by their families, and usually has a special meaning to an individual member of the crew, or is applicable to their daily activities. Contingency mission STS-324 was the designation given to the Contingency Shuttle Crew Support mission which would have been launched in the event Space Shuttle Endeavour became disabled during STS-123. It would have been a modified version of the STS-124 mission and would have involved the launch date being brought forward. The crew for this mission would have been a four-person subset of the full STS-124 crew. Media References External links STS-123 Endeavour landing NASA Assigns Crew for Japanese Lab and Canadian Robotics Mission NASA Assigns Crew for Shuttle Mission to Install Japanese Lab, Spaceref.com, March 22, 2007 Up to the minute updates of STS-123 Mission The STS-123 Official Flight Kit Manifest Space Shuttle missions Spacecraft launched in 2008 Spacecraft which reentered in 2008 Articles containing video clips