William Atkins
Thursday, 12 March 2009 03:48
Science -
Space
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With only about seven hours before liftoff of NASA’s STS-119 mission to the International Space Station, a hydrogen gas leak was discovered in the same system that has been perplexing shuttle engineers at NASA for weeks.
On Wednesday, March 11, 2009, NASA was preparing to launch the astronaut crew of STS-119 to the International Space Station for another important assembly mission.
Beginning just before noon local Florida time, launch technicians at the launch pad were gassing up the shuttle with over one-half million gallons of liquid hydrogen and liquid oxygen, which goes to fuel the Main Engines of the orbiter from its store within the external tank.
The scrubbed launch on Wednesday was supposed to occur at 9:20:10 p.m. Eastern Daylight Time (EDT).
However, a small leak was detected at about 2:30 p.m. EDT in the gaseous hydrogen vent line, what is called the GH2 line. Consequently, technicians were forced to drain the fuel from the ET, and a few minutes later an official call-off of the launch occurred.
According to a NASA statement,
“NASA officials scrubbed Wednesday's attempt at 2:37 EDT to launch space shuttle Discovery after a slight leak was detected in a gaseous hydrogen (GH2) vent line. The vent line is at the intertank region of the external tank and is the overboard vent to the pad and the flare stack where the vented hydrogen is burned off." [SpaceFlightNow.com: “
Launch of shuttle Discovery scrubbed by leak”]
In past news, the hydrogen gas flow control values (FCVs), part of the Space Shuttle Main Engines (SSMEs) has been causing NASA headaches for over one month now.
However, this problem was not with these values, but with another part of the system.
More information on these problematic valves is found in the iTWire article “
After many valve problems, it’s a GO for STS-119 shuttle launch,” which contains links to other articles written about this FCV problem.
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