Space shuttle Endeavour is in place at Launch Pad 39A at NASA's Kennedy Space Center in Florida, undergoing final preparations for its upcoming 16-day mission to the International Space Station. Mission STS-127 is the 32nd flight dedicated to station construction, and the final of a series of three flights dedicated to the assembly of the Japanese Kibo laboratory complex.The STS-127 payload is the Kibo Japanese Experiment Module Exposed Facility and Experiment Logistics Module Exposed Section.

Mark L. Polansky will command the shuttle Endeavour for STS-127. Douglas G. Hurley will serve as the pilot. Mission specialists are Christopher J. Cassidy, Thomas H. Marshburn, David A. Wolf and Julie Payette, a Canadian Space Agency astronaut.

The mission will deliver Timothy L. Kopra to the station as a flight engineer and science officer and return Japanese astronaut Koichi Wakata to Earth. Hurley, Cassidy, Marshburn and Kopra will be making their first trips to space.

Endeavour sets sail on its 23rd mission with the Kibo Japanese Experiment Module Exposed Facility and Experiment Logistics Module Exposed Section. The facility will provide a type of "front porch" for experiments in the exposed environment, and a robotic arm that will be attached to the Kibo Pressurized Module and used to position experiments outside the station. The mission will include five spacewalks.

STS-127 is the 29th shuttle mission to the International Space Station.

A gaseous hydrogen leak on a vent line for space shuttle Endeavour is postponing this morning's launch. The official scrub time was 12:26 a.m. EDT. Launch teams began draining Endeavour's external fuel tank of its liquid hydrogen and liquid oxygen at 12:06 a.m. Fueling was halted after the leak was detected near the Ground Umbilical Carrier Plate, or GUCP, which attached to the external tank at its intertank area. The line leads from the GUCP back to the launch pad and to the "flare stack" where vented gaseous hydrogen is burned off. The leak is similar to what happened during the first launch attempt of space shuttle Discovery's STS-119 mission in March. After the leak is assessed, shuttle managers plan to meet Saturday morning to discuss what steps to take next, including targeting a new launch date for Endeavour's STS-127 mission to the International Space Station.

The earliest the shuttle could be ready for liftoff is June 17, however there is a range conflict on that date with the scheduled launch of the Lunar Reconnaissance Orbiter/Lunar Crater Observation and Sensing Satellite from Cape Canaveral Air Force Station, Fla.

At NASA's Kennedy Space Center, launch managers met to discuss filling space shuttle Endeavour's external fuel tank in preparation for the STS-127 launch scheduled for 5:40 a.m. tomorrow. Due to current weather conditions, fueling will not begin as scheduled at 8:15 p.m. There is currently a 40 percent chance of weather prohibiting tanking as a result of anvil clouds and lightening in the area. Managers will continue to monitor weather conditions. Teams can begin tanking as late as 10 p.m. without impacting tomorrow's launch attempt.