From: LARRY KLAES (ljk4_at_msn.com)
Date: Sun Feb 02 2003 - 17:45:54 PST
----- Original Message -----
From: Bruce Moomaw
Sent: Sunday, February 02, 2003 7:52 PM
To: planetary_sciences_at_yahoogroups.com
Cc: Simon Mansfield; ISSDG; Jupiter List; Europa Icepick; Michelle Bledsoe
Subject: The puzzle starts to come together
Sequence of events from today's news conference:
7:53 AM -- Temperature inside left wheel well starts to rise (20 deg over
the next 5 minutes). Simultaneously, left elevon temperature sensors (whose
signal line runs through the wheelwell) all fail. At this time, Shuttle is
flying over east California -- and at about this point, CalTech scientistst
Dr. Binkley sees a cloud of small debris come off the Shuttle, and delivers
a signed statement to NASA to that effect. (Other unspecified witnesses in
California and Arizona also report seeing it.)
7:54 -- Temperature of Shuttle skin in an area immediately under the tiles
on its left side ABOVE the wing starts to rise -- 60 deg over 5 minutes (as
opposed to a 15 degree rise on the right side).
7:58 -- Autopilot starts to respond to modest rise in drag on Shuttle's left
side -- indicating either major roughness in tiles or patch of missing
tiles -- by adjusting the left elevon to compensate. Simultaneously, more
engineering sensors inside left wheel well start to fail at diffferent
times.
7:59 -- Drag problem increases and autopilot works harder to compensate.
8:00 -- Loss of voice signal (at a time when the autopilot still is nowhere
near reaching its maximum control limits).
32 seconds of scrambled -- but probably partially interpretable --
engineering telemetry after loss of voice contact. This is now starting to
be deciphered. (Although this wasn't mentioned at the conference, one
obvious possible interpretation is that the Shuttle was tumbling.)
As for that fragment of white debris seen coming off the "bipod" (the two
struts attaching the Shuttle's nose to the external tank) 80 seconds after
launch: Norman Thagard confirms that the tank's foam is actually very soft
material, and only produces a streak even when it hits a Shuttle window.
HOWEVER: Shuttle engineer Randy Avara reveals that CNN has another piece of
videotape showing the incident more clearly from another angle, and that the
white debris bounced off the Shuttle's left underside and broke into a cloud
of fragments -- which vaporized as they approached the exhaust flames.
The implications, I think, are clear: loss of tiles due to a big hard chunk
of ice falling off the tank and hitting them. (Thagard confirms that ice
would be much more worrisome than the tank foam.) Damaged tiles then start
to strip away -- probably from two separate places on the Shuttle's left
side -- during early re-enetry, and burnthrough begins in the left
wheelwell. The final failure may have been due to the autopilot simply
being strained beyond its abilities by a still further increase in left-side
drag -- or the left elevon control line may have broken, as the telemetry
leads had.
One other big story: some remains of all seven astronauts have been
recovered, apparently from a wooded patch filled with big pieces of the crew
compartment. (No further details.)
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