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Shuttle launch delayed until July Shuttle launch delayed until July
(10 minutes later)
A new leak during fuelling has forced Nasa to postpone the launch of space shuttle Endeavour until July at the earliest.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.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.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).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."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.""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.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.
We were just not comfortable pressing on Mike Leinbach, Nasa
"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."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.""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."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."He added: "We will fly home to Houston this morning."
Sun angle
Launching before July 11 is no longer an option because of the angle of the Sun between 22 June and 10 July.Launching before July 11 is no longer an option because of the angle of the Sun between 22 June and 10 July.
The shuttle would overheat if it was docked at the space station during this period of time. 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.
FROM BBC WORLD SERVICE More from BBC World ServiceFROM BBC WORLD SERVICE More from BBC World Service
Endeavour was set to deliver the third and last segment of Japan's Kibo laboratory aboard the ISS.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.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 pounds of food for the six space station occupants. 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.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.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 HoustonMark 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.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.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.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.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.Lift-off of the unmanned spacecraft is now being targeted for Thursday or Friday.