NASA postponed space shuttle Endeavour's launch to the International Space Station on Saturday because of a leak associated with the gaseous hydrogen venting system outside the shuttle’s external fuel tank. The system is used to carry excess hydrogen safely away from the launch pad. Managers scrubbed the launch for at least 96 hours.

The earliest the shuttle could be ready to launch is June 17. However, there is a conflict on the Eastern Range that date with the scheduled launch of the Lunar Reconnaissance Orbiter/Lunar Crater Observation and Sensing Satellite.

Mission managers will hold a meeting at 2 p.m. EDT Sunday to discuss the repair options and Endeavour's launch opportunities. A news conference will follow the meeting and air on NASA Television and the agency’s Web site.

The 16-day mission will feature five spacewalks and complete construction of the Japan Aerospace Exploration Agency's Kibo laboratory. Astronauts will attach a platform to the outside of the Japanese module that will allow experiments to be exposed to space.

The STS-127 crew members are Commander Mark Polansky, Pilot Doug Hurley and Mission Specialists Dave Wolf, Christopher Cassidy, Tom Marshburn, Tim Kopra and Canadian Space Agency astronaut Julie Payette. Kopra will join the space station crew and replace Japanese astronaut Koichi Wakata. Wakata will return to Earth on Endeavour to conclude a three-month stay at the station.

Polansky, who has a Twitter account named Astro_127, can be followed online at:

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For the latest information about the STS-127 mission and its crew, visit:

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http://www.nasa.gov/station