NASA is chilling down lines that will route supercold propellants into the external tank of shuttle Discovery, initiating a test that could aimed at pinpointing the cause of mission-delaying cracks in the 15-story fuel reservoir.More than 535,000 gallons of cryogenic liquid hydrogen and liquid oxygen will be loaded into tank during the next three hours. Almost 90 strain gauges and thermal sensors will gauge the amount of contraction and expansion seen in the aluminum-lithium hull of the tank, as well as temperatures.
The data will be evaluated to try to determine the cause of four cracks found in structural braces in the mid-section of the tank. The concern is that cracks underlying thermal insulation could cause foam to pop off during flight and strike vulnerable shuttle heat shield components.
You can watch live coverage of the test here in The Flame Trench. Click the NASA TV box on the right side of the page to launch our NASA TV viewer. NASA public affairs specialist Allard Beutel is providing commentary and will be interviewing several shuttle managers about the cracks and how NASA will position itself for a planned Feb. 3 launch.
The test had been slated for earlier this week but was delayed by unusually cold weather. Average temperatures during a 24-hour period prior to tanking cannot drop below 41 degrees, and the single lowest temperature during that same timeframe cannot dip below 33 degrees, in order for a test to proceed.
The criteria are the same used to determine whether fuel-loading operations can proceed in advance of a launch attempt.
1 comment:
Anyone like to take a wag at how much $$$$ this little experiment cost those of us on the federally mandated tax contribution program??
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