Leak Pushes Discovery Shuttle Launch to at Least Nov. 30
By: Chloe Albanesius- 11.05.2010
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A hydrogen gas leak discovered on the Space Shuttle Discovery has now pushed its launch from Monday until at least November 30, NASA officials said Friday.
In responding to the hydrogen leak, a mission team also discovered a seven-inch crack on the shuttle's external tank, though that was found after the fact and did not influence the decision to push the launch to the end of the month, Mike Moses, chair of the pre-launch mission management team, said during a Friday press briefing.
The hydrogen leak was discovered early this morning as the crew was fueling Discovery for a planned Friday launch. It occurred at the Ground Umbilical Center Plate (GUCP) that attaches to the external tank; the GUCP carries gaseous hydrogen safely away from the shuttle to a flare stack, where it burns off, according to NASA.
At this point, NASA is not exactly sure what is causing the leak. It was discovered in the midst of the fueling process, so officials have to drain the tank before they can go in and inspect it. It currently houses residual oxygen that needs to boil off before any assessment can be made. That takes about 24 hours, so officials will have to wait until at least tomorrow morning before they can start troubleshooting.
NASA toyed with the idea of a Monday launch, Moses said, but given that they do not know what is causing the leak or how long it might take to fix it (not to mention the crack) "we need to take our time," Moses said.
They will have to wait until at least November 30 because for the next few weeks, the sun will be at an angle that won't sufficiently heat the shuttle. But November 30 is not a "hardcore, set date," Moses said. "We suspect … that's plenty of time to fix that problem, but you never known what you're going to find."
"I suspect in the next couple weeks, we'll settle on a date we really want," he said.
If things don't happen in the November 30 timeframe, the next window for launch will not happen until February, Moses said.
Moses and Mike Leinbach, Shuttle launch director, said their teams have encountered leaks in the GUCP twice before, but Friday's leak showed up much earlier in the process and was more significant. Previous leaks occurred on STS-119, which launched in March 2009, and STS-127, which launched in July 2009 – but not until fueling was almost done.
Leinbach said fueling is a four-stage process: a chill down, where gas flows through the system into the tank; a slow fill; a fast fill; and a topping phase. On STS-119 and STS-127, the leaks showed up during topping. Today, officials discovered it during fast fill.
"It was a significant leak and occurred sooner than we'd seen in the past," Leinbach said.
Moses said he hopes the problem is "glaringly" obvious when the crew goes in there, so they can fix it as soon as possible.
How is the team holding up after multiple delays? "It's frustrating, [but] these things happen," Moses said. "This is the way the space business works."
He acknowledged that there were likely some logistical annoyances as crew members had to change hotel and flight plans throughout the week, but in terms of the team, "everybody reacted exactly the way they [should]; the engineering team was immediately on top of things," Moses said.
In the control room, "I probably had six or seven people come up to me … and say 'good decision,'" Leinbach added. "We want to do the right thing for this vehicle."
Leaks and weather issues have delayed the shuttle launch several times throughout the week. The shuttle was initially scheduled to launch on Monday, but helium and nitrogen leaks in the pressurization portion of space shuttle pushed that to Tuesday. When repairs related to those leaks lasted longer than expected, NASA again delayed the launch to Wednesday. Electrical issues prevented launch on that day, however, while the Cape Canaveral weather marred a Thursday launch. (PCmag)
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