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NASA Unable to Find Cause of Discovery Sensor Failure
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(http://enews.voanews.com/t?ctl=E57C74:3919ACA

NASA officials say Tuesday's scheduled launch of Discovery remains on
track, even though technicians have been unable to fix a fuel sensor
failure that halted the countdown earlier this month





The Space Shuttle Discovery sits on Launch Pad 39B at the Kennedy
Space Center at Cape Canaveral, FloridaU.S. space agency officials say
Tuesday's scheduled launch of the shuttle Discovery remains on track,
even though technicians have been unable to fix a fuel sensor failure
that halted the countdown earlier this month. 

The countdown for Discovery's flight to the International Space
Station was halted on July 13 shortly after technicians discovered a
malfunctioning hydrogen fuel sensor.

The flight would end a two and a half year hiatus for the space
shuttle program, which was grounded after the Columbia disintegrated
upon reentering earth's atmosphere in February 2003, killing it's
seven member crew.

On Saturday, mission controllers began counting down anew for lift off
on Tuesday, but space agency officials are still not sure why the
hydrogen sensor gave a low reading despite the fact that the fuel tank
was full.

Space shuttle program manager Wayne Hale said Sunday technicians have
run through every possible check they could think of to see if they
could duplicate the failure, but without success.

NASA technicians have also rewired two of the four sensors to see if
the problem is in the wiring or the master sensor itself.  He says
there's still no word.







Wayne Hale "I don't want anybody to go away with the idea that we're
indicting the sensors," Mr. Hale says. "As a matter of fact, while it
could always be that we had a sensor failure, that is just one of the
things that we have got on our list of topics to look at."

Mr. Hale says technicians are looking for unusual causes for the
faulty sensor reading, including unexpected ice formation. 

NASA Administrator Michael Griffin says he's comfortable that space
agency officials are doing what's necessary to ensure the safety of
the mission.

"Look, I think what you want coming out the Columbia accident and the
loss of Columbia and the soul searching examination that NASA has
undertaken since then is that we make the right technical decisions,
that we do the right thing, to the extent that we can figure that out,
which is hard," Mr. Griffin indicated.

NASA officials say there's a 40 percent chance Tuesday's lift-off
could be postponed due to weather.  If that happens, the next possible
launch date would be August 4.