Bruce,
Ice on the main fuel tank, with enough build-up to break off in large pieces and strike the soft tiles on the shuttle. Is this build-up always the case, or are we witnessing yet another disaster brought about, or at least exacerbated by winter launches? The first time it was frozen, brittle o-rings on the boosters, due at least in part to extremely cold weather at launch.
Gary
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.) == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
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