[r9etb]

I am surprised they are taking it down this close before deciding on the sensor issue. Florida Today still reports a scrub is likely but NASA is still pressing ahead with less than 2 hours to scheduled liftoff. The drama is making me more nervous.

If I'm not mistaken, this sensor is part of the ground support equipment, and is designed to check for hydrogen around the base of the Shuttle. There are three other sensors, so they're not really blind...

[markman46]

I believe these are the ET sensors, and there are 8 4 for the O2 and 4 for the Hydrogen, one of the hydrogen sensor tested bad.