NASA mission officials scrubbed the STS-127 mission early Wednesday morning, June 17, 2009, after the leak appeared during the routine filling of the external fuel tank (ET) with gaseous hydrogen fuel.
Even without the leak, the pre-launch team was having difficulties filling the fuel tanks because of severe thunderstorms passing over the Florida launch site.
They were already three hours behind schedule, and under pressure to make the fixed deadline of a 5:40 a.m. launch time.
The leak appeared at the same spot where it was earlier spotted, which lead to the postponing of the June 13 launch to June 17.
According to the NASA news brief Fuel leak again postpones launch of space shuttle Endeavour, “The gaseous hydrogen venting system is used to carry excess hydrogen safely away from the launch pad. Wednesday's leak is similar to one that prevented Endeavour's launch on June 13.”
The mission will have to wait until July 11, its next launch opportunity, because of a restriction called a beta angle.
More information on the beta angle, and NASA's mission to the Moon, which is scheduled to launch on Thursday or Friday, is found on page two.
This beta angle states the percentage of time that the shuttle, in this case, spends in direct sunlight.
In other words, the shuttle's skin needs the heat from sunlight to function properly, and the percentage needs to be above 59% for proper conditions to exist in space for the shuttle.
Between June 22 and July 10, the beta angle percentage is below 59% so it creates a mission condition that prohibits the shuttle from docking to the space station.
NASA states, “The 16-day mission to the International Space Station 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.”
At this time, it was unknown if NASA would have the leak fixed by the July 11 date.
On the bright side, the LRO/LCROSS launch, which was delayed one day to allow Endeavour the chance to launch, is right on schedule to be launched either on Thursday, June 18, or Friday, June 19. The LRO/LCROSS mission is an unmanned mission to explore the Moon.
For additional information, on the Moon launch and mission, please go to the June 3, 2009 NASA article “The LRO/LCROSS Flight to the Moon.”
The article states, “The LRO/LCROSS mission hopes to discover what the moon has to offer for the future moon dwellers.”