SOunds more like a problem with high humidity than with low temperature. Are there any records of the humidity for that day available?
Joe L. On Sun, 2003-02-02 at 17:35, Gary McMurtry wrote: > > 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/ > > > == > You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] > Project information and list (un)subscribe info: http://klx.com/europa/ == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
