gandalf@pro-canaveral.cts.com (Ken Hollis) (11/23/90)
Greetings and Salutations: >From: LABRIE@gecrdvm1.crd.ge.com >Subject: Tiles >Columbia or Enterprise gliding in with about a third of its tiles missing If you are referring to the time that Columbia was ferried from Palmdale back to KSC aboard the SCA (Shuttle Carrier Aircraft), The missing "Tiles" you saw was the initial removal of the dice tiles to later be replaced by AFRSI (Advanced Felt Reusable Surface Insulation). There has never been a massive loss of tiles From Re-entry. >of the shuttle. You can expect about 500 to 1000 of these tiles to be damaged >per flight. Most can be repaired in place by drilling out the pits or holes, >filling with paste, and sanding smooth. But about 100 to 150 of these will >be beyond repair and need to be replaced. Technicians have to carefully About a dozen or so are so damaged that they have to be replaced, with a total of maybe 100 tiles hit plus or minus 25. >of the blankets. An easy way to tell most of the tiles from the blanket >squares is, the tiles are usually black or grey and the blankets are white. The grey parts are reinforced carbon-carbon for high temperature areas. >John E. Labrie >GE Corporate Research and Development >Schenectady, New York USA >From: dil@mace.cc.purdue.edu (Perry G Ramsey) >Subject: Re: Tiles >Discovery and Atlantis have a lot of white tiles. Challenger and Columbia >had/have a lot more. >Perry G. Ramsey Department of Earth and Atmospheric Sciences Columbia used to have the 1" dice tiles all over the vehicle, but they also have been replaced with the AFRSI (essentially quartz blankets impregnated with ceramics). Columbia still has large white tiles on the crew module. The other vehicles are basically all AFRSI except on small areas on the OMS pods on the front near where the black tile is, and on the side where the black tile is (the black tile was installed after high heating areas were noticed & there was a burn-through on the side of the OMS pod). There is also some white tile on the nose around the windows. By the way, the black "Glove" area on Columbia (The front part of the upper wing that is black, unlike the other two orbiters) is FRSI painted black, and is not tile. At one time there was a thought that this part of the wing would have to be warmed up more during the barbecue rolls for reentry. It was found out that is is not required. Ken Hollis ProLine: gandalf@pro-canaveral Internet: gandalf@pro-canaveral.cts.com UUCP: crash!pro-canaveral!gandalf
shafer@skipper.dfrf.nasa.gov (Mary Shafer) (11/23/90)
In article <5818@crash.cts.com> gandalf@pro-canaveral.cts.com (Ken Hollis) writes: >From: LABRIE@gecrdvm1.crd.ge.com >>Columbia or Enterprise gliding in with about a third of its tiles missing >If you are referring to the time that Columbia was ferried from Palmdale back >to KSC aboard the SCA (Shuttle Carrier Aircraft), The missing "Tiles" you saw >was the initial removal of the dice tiles to later be replaced by AFRSI >(Advanced Felt Reusable Surface Insulation). There has never been a massive >loss of tiles From Re-entry. No Shuttle is ever ferried from Palmdale. They don't have a mate-demate device there, so the Shuttle is towed from the north side of Plant 42, through Lancaster, onto Edwards AFB. (One of Henry Spencer's AvLeak digests mentioned that the MDD from Vandenberg was going to be moved to Palmdale to make good this deficiency.) Columbia's tiling had fallen behind schedule and a decision was made to take it and its tiling team to KSC, so that the tiling could be completed there, synchronously with other, internal work. I believe that temporary tiles, a la the Enterprise's painted styrofoam, were installed to reduce drag and protect the underfelting. These were either poorly attached or not flexibly enough attached and they were shed (to the tune of "The Autumn Leaves Come Drifting Down"?) during the mating, taxi-ing, and takeoff. This was, of course, before the first Shuttle flight. The removal of dice tiles for AFRSI (pronounced A-frizzy) happened much later in the flight program. >By the way, the black "Glove" area on Columbia (The front part of the upper >wing that is black, unlike the other two orbiters) is FRSI painted black, and >is not tile. At one time there was a thought that this part of the wing would >have to be warmed up more during the barbecue rolls for reentry. It was found >out that is is not required. The barbeque mode is used on orbit, for temperature control. Those re-entry rolls are used for kinetic and potential energy dissipation, not for temperature control. It is correct that they initially believed that that area would get hotter than it does, but the rolls aren't used to warm it up. Or are you saying that they thought it would get hotter but found, in actual flight, that it didn't and that the FRSI wasn't needed, that the tiles could handle it? That wouldn't surprise me, but it wouldn't be the rolls making the difference. -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot