launch delayed until July

Shuttle

Deputy space shuttle programme manager LeRoy Cain: "We're going to step back and figure out what the problem is" A new leak during fuelling has forced Nasa to postpone the launch of space shuttle Endeavour until July at the earliest. The shuttle was due to blast off from Florida early on Wednesday, but hydrogen gas leaked from a vent line on its external fuel tank, officials said. A previous gas leak postponed the shuttle's launch on Saturday. Endeavour had been due to deliver part of a Japanese laboratory to the International Space Station (ISS). "At 1.55am (05.55 GMT) launch managers called a scrub, cancelling today's planned launch of space shuttle Endeavour on its STS-127 mission," a Nasa statement said. "Despite troubleshooting efforts, engineers were unable to achieve a decrease in the liquid hydrogen leak." For an hour after the leak appeared during fuelling, engineers tried to fix the problem through remote commands. But they were finally forced to call off the pre-dawn launch from Florida's Kennedy Space Center. "I sure wish we could have rewarded them and the astronauts and everybody else with a launch this morning," said assistant launch director Mike Leinbach. "But the leak was way out of spec again, and so we were just not comfortable pressing on." The shuttle's commander Mark Polansky commented: "It's a reminder that spaceflight is not routine."He added: "We will fly home to Houston this morning." Launching before July 11 is no longer an option because of the angle of the Sun between 22 June and 10 July. Nasa is concerned about something called the beta angle cut-off. The beta angle defines the percentage of time a spacecraft in low-Earth orbit spends in direct sunlight. Data suggests the shuttle could overheat if it was docked at the space station during those dates. Endeavour was set to deliver the third and last segment of Japan's Kibo laboratory aboard the ISS. Once the launch goes ahead, the astronauts will carry out five spacewalks to attach a permanent platform weighing 1.9 tonnes to Kibo. They will also take up hundreds of kilograms of food for the six space station occupants. A new ISS resident also was supposed to go up and swap places with a Japanese astronaut who has been on the station since March. During the mission, the ISS will be a temporary home to 13 astronauts - the first time so many have stayed on the station at once. Mark Polansky (l) says the crew are now on their way back to Houston The launch coincides with the first public hearing of the Review of US Human Space Flight Plans Committee in Washington DC. This sweeping independent review of Nasa's manned spaceflight strategy was announced by the White House in May this year. Among other things, it will examine development of the replacement vehicle for the space shuttle, Ares-Orion, and Nasa's plans to return to the Moon by 2020. The shuttle's new target date caused a scheduling conflict with the launch of the Lunar Reconnaissance Orbiter (LRO) satellite and its partner mission LCROSS. Lift-off of the unmanned spacecraft is now being targeted for Thursday or Friday.