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2006-09-21 Science & Technology

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Posted by Bobby 2006-09-21 06:58|| || Front Page|| [2 views since 2007-05-07] Top

#1 Welcome home, Atlantis. I turned on the teevee this am and saw it land live. Very cool.

Posted by Seafarious">Seafarious 2006-09-21 09:01|| 2006-09-21 09:01|| Front Page Top

#2 Welcome back... awsome job.

Blackvenom-2001

Posted by Blackvenom-2001 2006-09-21 09:58|| 2006-09-21 09:58|| Front Page Top

#3 Those tiles are hard.

Much like glass, which is harder than metal, many hard materials are also quite brittle.

The black areas on the Orbiter are covered with blocks or tiles of varying size and thickness. These are called "high-temperature reusable surface insulation", or HRSI tiles. HRSI tiles protect areas where temperatures are between 650°C (1200°F) and 1275°C (2300°F).
On Columbia, white tiles cover the forward fuselage, outer wing areas, pods, and the stabilizer. Called "low-temperature reusable surface insulation", or LRSI, these tiles are used where temperatures are between 370°C (700°F) and 650°C (1200°F).

Columbia's cargo-bay doors, fuselage sides, upper wing surfaces, and aft areas of the OMS pods are covered with a Nomex felt material. These areas remain below 370°C (700°F) during flight.

Altogether, nearly 32,000 HRSI and LRSI tiles cover Columbia. No two tiles are alike and each must be installed by hand. Both types of tiles are made from extremely pure (99.5%) sand. The sand is crushed into very small silica fibers and added to a ceramic binder. This mixture is fired to produce the blocks. They are machined to the proper size and shape, then the black or white coating is applied to their outer surfaces. The coating is made from a high-strength refractory glass.

An aluminum structure like that of the Orbiter flexes and bends slightly in flight. The TPS (thermal protection system) tiles covering the vehicle must be very close together. On the underside, the largest allowable gap between tiles is only 0.065" (1.6 mm). These glass-covered silica tiles are rather brittle and cannot flex or bend without breaking. To let the structure flex while keeping the TPS rigid, Nomex felt pads are sandwiched between the tiles and the structure. This way, the structure can move without moving the tiles. The pads and the tiles are attached with a thin layer of a room temperature vulcanizing silicon adhesive.

Posted by Zenster">Zenster 2006-09-21 10:11|| 2006-09-21 10:11|| Front Page Top

#4 Asked to identify the origin of the debris observed over the past two days, Hale said: "All those items come from the space shuttle."

Sewage, in other words.

Posted by Rob Crawford">Rob Crawford 2006-09-21 11:37|| http://www.kloognome.com/]">[http://www.kloognome.com/] 2006-09-21 11:37|| Front Page Top

#5 Yeah, I know hardness and brittleness are often related, until you get toughness in there...

But I can still remember seeing a tile demonstration - before the first shuttle flew, IIRC - that showed a tile heated red hot by a propane torch. Within a few seconds, the edges had cooled to black, and the guy was able to pick it up, even tho the center was still cherry red.

Made an impression.

Posted by Bobby 2006-09-21 18:09|| 2006-09-21 18:09|| Front Page Top

#6 Agreed, Bobby. That one demonstration totally blew my mind. I view the tiles as a mosaically formated replaceable ablative shield.

Posted by Zenster">Zenster 2006-09-21 18:50|| 2006-09-21 18:50|| Front Page Top

#7 To give you an idea of the temperature cycling that the shuttle goes through; The first thing they do once the bird finishes its landing rollout is pull up a truck full of LN₂.

The liquid nitrogen is pumped through the shuttle's frame in order to intercept and absorb the thermal pulse acquired during de-orbiting. If this was not done, the wiring harnesses and other sensitive instruments would melt like chocolate.

Posted by Zenster">Zenster 2006-09-21 18:57|| 2006-09-21 18:57|| Front Page Top

#8 Hmm... I didn't know about the LN2 afterwards, although I did a bit of engineering on the west cost shuttle lauch pad at Vandenberg, and remember LN2 lines near the giant shuttle 'defroster' - the ice supression system - powered by two surplus jet engines.

Far OUT.

Posted by Bobby 2006-09-21 21:19|| 2006-09-21 21:19|| Front Page Top

#9 I understand the gases around the Shuttle after landing are toxic too.

Posted by Eric Jablow">Eric Jablow 2006-09-21 21:51|| 2006-09-21 21:51|| Front Page Top

#10 My ex-Father in law, a real good guy - may he rest in peace, was the machinist at Ling-Temco-vaught that created the machining "jigs" used to create each tile - and all of them are unique, I believe. All of 'em, lol. I don't recall many details, now, but he was on it for at least a year. He was a bona-fide workaholic and did not last long after they made him retire.

Posted by .com 2006-09-21 22:18|| 2006-09-21 22:18|| Front Page Top

#11 Vought, sheesh. Pimf.

Posted by .com 2006-09-21 22:24|| 2006-09-21 22:24|| Front Page Top

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