KENNEDY SPACE CENTER, Fla., July 26, 2005
NASA's Shuttle Strategy
Bill Harwood On Preparations For Discovery's Launch
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Play CBS Video Video NASA Hopes For Launch For the second time this month, the countdown is under way to get the space shuttle Discovery off the ground. But there are no guarantees, Mark Strassmann reports.
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Video Discovery Shuttle Update CBS News' Mark Strassmann has an update on the Space Shuttle Discovery's anticpated launch from Cape Canaveral, Florida.
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Discovery's crew (L-R): front row, James Kelly, Wendy Lawrence and Eileen Collins; back row, Stephen Robinson, Andy Thomas, Charles Camarda and Soichi Noguchi. (AP Photo/NASA)
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Space shuttle Discovery (CBS)
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Interactive Shuttle Era Follow the history of America's space shuttle program.
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Interactive Test Flights The shuttle program gets back off the ground as Discovery returns to space.
To help isolate the problem, engineers swapped the wiring between ECO sensors 2 and 4. If a problem shows up during fueling with sensor No. 4, engineers will have high confidence the problem is in the sensor itself or somewhere in the wiring between the sensor and an electrical component called a point sensor box. If sensor No. 2 misbehaves, they will have high confidence the problem is in the point sensor box.
Here's the ECO sensor launch strategy at a glance:
Because of the wiring swap, "if the problem recurs, it will give us an indication of whether the problem is in our famous point sensor black box or in the wiring or the sensor itself," Hale said. "So we'll know that. And we've defined a very rigid set of requirements and tests to be done if this problem re occurs. We also know that we've done a lot of moving around in the aft, we've mated and demated connectors, we've wiggled a lot of wiring, we've tested the point sensor box extensively and it is possible that we have caused whatever the problem was to go away.
"So if the problem doesn't recur, we feel we have good redundancy to go fly and that's why we are prepared, following the tests to ensure all these sensors are working right ... to load the crew up and go fly."
But if sensors 2 or 4 act up, "then we're going to do some more tests just to make sure we understand what's causing that to happen," Hale said. "And if we're comfortable that we have a good understanding of the cause, then we can go fly for those specific two cases. If anything else happens - if we have any of the liquid oxygen sensors fail, if we have a hydrogen sensor that fails to a dry state instead of the wet state, if we have a sensor that fails on channel 1 or 3 or multiple sensor failures, anything like that happens - we're going to stop because that says we really need to do more testing."
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