Same Problem Cropped Up Last Year

Last week, Aero-News reported on NASA's tight schedule for launching three shuttle missions this year. The slightest glitch could throw that schedule off, NASA said at the time... and now, it appears such a glitch may have occurred.

The trouble is with the shuttle Discovery's problematic external fuel tank. A critical fuel-depletion sensor, once known as an emergency cutoff sensor, is giving unusual readings, NASA engineers said Tuesday.

NBC news reports it's the same type of problem that plagued the countdown of Discovery's "Return to Flight" launch last July. Scientists ultimately decided to launch then, despite the intermittent problem.

It's not known yet if the problem sensor -- which displayed what one scientist described as "a very slight shift" during electrical tests -- will need to be replaced this time around. It is also not known how the problem might affect Discovery's scheduled May 10 launch window.

Should engineers decide the problem sensor needs to be replaced, one anonymous source told NBC News the job might require no more than an additional week of work -- leaving the door open for a possible launch between May 17-23. But others say it could take much more time.

Even if the scheduled May launch is delayed until July, NASA says it is possible they could still fly two more missions after before the end of 2006.

That schedule would rely on EVERYTHING going right, though... and so far, the fuel sensor isn't the only issue causing some grief for engineers working to ready Discovery for launch.

While maneuvering a boom-mounted platform in the Vehicle Assembly Building to clean up debris caused by a broken ceiling lamp this week, workers accidentally caught the shuttle's robot arm with the edge of the platform. The arm was stowed in its position along the left side of the shuttle's payload bay.

Inspections are now underway to make sure the arm suffered no mechanical damage. As workers slave to meet NASA's admittedly tight schedule, sources told NBC, such operator errors have become more common of late... as workers pull double shifts.

FMI: www.nasa.gov