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RE: Shuttle inspection: More info



Hi!
	I found more info...

 > >	Could it be wiring that they are inspecting? My shuttle status
 > >messages indicate a fleet wide inspection of wiring. A short in one
of
 > >them during the last mission would have caused some engine
controllers
 > >to fail. They are looking more closely to see where it occurs, and
how
 > >to prevent it in the future.
 >
 > thought it was a couple of the GPC's that shut down .. I do know
they came
 > closer than they ever have to an RTLS abort.  That would have been a
pretty
 > spectacular failure ..

	Here is what they say about it:
(From http://www-pao.ksc.nasa.gov/kscpao/chron/sts-93.htm)

"About 5 seconds after liftoff, flight controllers noted a voltage
drop on one of the shuttle’s electrical buses. Because of this voltage
drop, one of two redundant main engine controllers on two of the three
engines shut down. The redundant controllers on those two engines --
center and right main engines -- functioned normally, allowing them to
fully support Columbia’s climb to orbit. "

	I do not remember ever hearing of an abort condition of any kind
declared after liftoff. As there been any? Sure Challenger could have
been a candidate here... Anyway, I learned from their Shuttle Team
Online Q&A list that these maneuvers had never been tested yet... Must
be too expensive to "cancel" a launch to test them...

 >
 > >	Also, some debris would have damaged one of the main shuttle
engine's
 > >bell, causing a small hydrogen leak in the bell's cooling system,
and
 > >a small plume outside the bell during the last liftoff...
 >
 > heard about that .. never saw video but apparently one of the SSME's
was
 > showing signs of very anomalous operation.

(From http://www-pao.ksc.nasa.gov/kscpao/chron/sts-93.htm):
"The orbit attained, however, was 7 miles short of that originally
projected due to premature main engine cutoff an instant before the
scheduled cutoff. This problem was eventually traced to a hydrogen
leak in the No. 3 main engine nozzle. The leak was caused when a
liquid oxygen post pin came out of the main injector during main
engine ignition, striking the hotwall of the nozzle and rupturing
three liquid hydrogen coolant tubes. "

	If you want to see pictures of the shuttle's liftoff with close-ups
on the plume, go there: http://www.dransom.com/sts93.html

	If you want to see photos of the damaged cooling lines, also see:
http://shuttle.nasa.gov/shuttle/archives/sts-93/leak.html

 > Definitely time to ground the fleet and take a look at all the
hardware --
 > I know they look it at during turnaround at the OPF but maybe it's
time
 > to do a major teardown.
 >

	Not to worry: They do so regularly... From the Status mail list:

"Orbiter Columbia continues to undergo routine post flight-deservicing
in
Orbiter Processing Facility bay 3. Workers are preparing the orbiter
for its
upcoming Orbiter Maintenance Down Period (OMDP) in Palmdale, CA.  Once
at
Palmdale, extensive wiring inspections will be conducted. Columbia is
scheduled to be mounted atop NASA's modified Boeing 747 on Sept. 22.
The
ferry flight from KSC is scheduled to begin on Sept. 23 with an
overnight
stop at Luke Air Force Base in Arizona.  Current plans have Columbia
arriving in Palmdale on Sept. 24.  Because the orbiter can not be
flown
through precipitation of any kind, ferry flight plans are contingent
upon
weather conditions in the flight path."

	Once in Palmdale, the whole shuttle will be inspected, refurbished,
upgraded, re-certified and so on... The launch of STS-93 HAD to be
before September, as the OMDP was already planned... Else, STS-93
mission would have been delayed again to next year... That would have
been the third time, I think.

	I hope that info can be useful. It took me 3 hours to find back the
dransom web site :(  I went there 3 weeks ago...

		Martin VE2MRX
[E_O_MSG]

mailto:ve2mrx@amsat.org
-----------------------
Martin VE2MRX
Beloeil, Quebec, Canada
FN35jn




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