...NASA has decided to go ahead with a launch of Columbia at 10:34am on Tuesday, even though they have not ascertained the cause of the fuel sensor problem that scrubbed the last launch. It was previously reported that NASA "might" go ahead and fly the Shuttle with a known bad sensor, although that report also stated that failure to shut down the engines before fuel is exhausted could cause an explosion. (This statement was not enlarged upon.)
This seems to me like a really bad idea, especially given that the previous NASA new release included a photo of a NASA engineer with a spare sensor in his hands on a table. If you have a spare, why not swap out the malfunctioning sensor and replace it with a known-good one? Then you can tear the malfing one down and find out why it's malfing.
NASA flight protocols require all four sensors to be working for a launch.
Parsons said NASA officials, as a contingency, are preparing for the possibility of waiving the requirement and sending up Discovery with just three working sensors. However, he said no decision has been made to change the protocol, and he said it wouldn't be done unless engineers are confident they understand the problem, even if they can't isolate it.
The current launch window ends July 31; the next window does not open until September 9. My call? Take the extra five weeks, and find and fix the problem. Fourteen Shuttle astronauts is already fourteen too many.