Post by thread:[OT]: Columbia - major tile damage from insulation

Here's a December 1997 report on major tile damage to Columbia in 1997 (STS-87) due to impact from foam from the ET. http://quest.arc.nasa.gov/people/journals/space/katnik/sts87-12-23.html Russell McMahon __________________________________ Excerpt: Damage numbering up to forty tiles is considered normal on each mission due to ice dropping off of the external tank (ET) and plume re-circulation causing this debris to impact with the tiles. But the extent of damage at the conclusion of this mission was not "normal." The pattern of hits did not follow aerodynamic expectations, and the number, size and severity of hits were abnormal. Three hundred and eight hits were counted during the inspection, one-hundred and thirty two (132) were greater than one inch. Some of the hits measured fifteen (15) inches long with depths measuring up to one and one-half (1 1/2) inches. Considering that the depth of the tile is two (2) inches, a 75% penetration depth had been reached. Over one hundred (100) tiles have been removed from the Columbia because they were irreparable. The inspection revealed the damage, now the "detective process" began. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

I was thinking about something. Why don't they put the insulation inside the tanks instead of outside ? It would have to be inert in contact with LoX but such things exist. If at least the top side of the tank would have the insulation foamed on the inside the risk of banging pieces against the shuttle would be lower, no ? There are these new substances (like glass foam) that would probably work. There is also the trick of not using insulation. I think that the big rockets used for Apollo missions did not have insulation on the first stage, just an air space, and they just boiled fuel off all the time until launch. Am I wrong ? Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

At 09:58 PM 2/28/2003 +0200, you wrote: >I was thinking about something. Why don't they put the insulation inside >the tanks instead of outside ? It would have to be inert in contact with >LoX but such things exist. If at least the top side of the tank would have >the insulation foamed on the inside the risk of banging pieces against the >shuttle would be lower, no ? There are these new substances (like glass >foam) that would probably work. There is also the trick of not using >insulation. I think that the big rockets used for Apollo missions did not >have insulation on the first stage, just an air space, and they just >boiled fuel off all the time until launch. Am I wrong ? I don't know, but I was wondering why the shuttle wasn't attached with the tiles to the outside. You'd think that the top would be a better place to put attachment points and the top of the orbiter is probably a lot more resistant to damage. Best regards, Spehro Pefhany --"it's the network..." "The Journey is the reward" spam_OUTspeffTakeThisOuTinterlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Fri, 28 Feb 2003, Spehro Pefhany wrote: *>At 09:58 PM 2/28/2003 +0200, you wrote: *>>I was thinking about something. Why don't they put the insulation inside *>>the tanks instead of outside ? It would have to be inert in contact with *>>LoX but such things exist. If at least the top side of the tank would have *>>the insulation foamed on the inside the risk of banging pieces against the *>>shuttle would be lower, no ? There are these new substances (like glass *>>foam) that would probably work. There is also the trick of not using *>>insulation. I think that the big rockets used for Apollo missions did not *>>have insulation on the first stage, just an air space, and they just *>>boiled fuel off all the time until launch. Am I wrong ? *> *>I don't know, but I was wondering why the shuttle wasn't attached with the *>tiles to the outside. You'd think that the top would be a better place to *>put attachment points and the top of the orbiter is probably a lot more *>resistant to damage. They would have to make the tail foldable like on some russian fighters ;-( I have read some articles on the way the reentry bodies were designed and built and tested and the tail was always a big problem. They just kept adding tail until it was too big and then they lived with it like that from what I understand. Peter -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Thermal tiles are fragile, you can transverse it with a pencil. They should be protected all the way until reentry. They are not necessary anyway until the shuttle returns and hit atmosphere at high speed. Even a thin metal foil all the way over the tiles would avoid the problem. Let it burn upon reentry, or just discard it in space before reentry. It is amazing to think that even a 3 lbs bird flying at 2000ft can damage seriously the tiles and plant a big risk at the reentry. The shuttle lift-off speed at 2000ft crash with the bird would be enough to damage several tiles. Based on the actual jokes around, perhaps some yards of Duct-Tape could hold the external tank foam in place... Wagner. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Could be related to size economies. I don't know how much foam they have to add, but perhaps the extra 2-10 inches diameter are needed for extra LOx, but can't be added interior for shipping/assembling reasons. Or it could simply be a cost cutting feature of the tank. -Adam Peter L. Peres wrote: {Quote hidden}>I was thinking about something. Why don't they put the insulation inside >the tanks instead of outside ? It would have to be inert in contact with >LoX but such things exist. If at least the top side of the tank would have >the insulation foamed on the inside the risk of banging pieces against the >shuttle would be lower, no ? There are these new substances (like glass >foam) that would probably work. There is also the trick of not using >insulation. I think that the big rockets used for Apollo missions did not >have insulation on the first stage, just an air space, and they just >boiled fuel off all the time until launch. Am I wrong ? > >Peter > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. > > > > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam@spam@mitvma.mit.edu with SET PICList DIGEST in the body