July 18, 2005
The Mystery Continues
Still no word as to the cause of the mysterious error on the Space Shuttle's Main External Tank fuel gauge. A comprehensive piece by Bill Harwood here sets out the current considerations.
The fact is that the shuttle currently requires four working fuel sensors for a launch. It is also a fact that the fourth fuel tank sensor is doubly redundant.
While it is possible that NASA might change its rules on the fly to permit launch with only three working sensors, it is unlikely. This launch will be under the microscope like none other, which means that if something went wrong after a decision to waive a flight rule, it would be a bad day for all involved.
Bet on no waiver of this flight rule, then -- which means that the only way for Discovery to get off this pad vertically before the end of July is if NASA engineers can track down the error and correct it over the next few days.
No one said it would be easy. The National Space Society sends its most sincere respect to the dedicated engineers who are currently working this problem around the country.
Posted by george_whitesides at July 18, 2005 03:59 PM