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Author
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Topic: Tyvek covers (WAS: debris seen in launch)
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Paul78zephyr
Member Posts: 675
From: Hudson, MA
Registered: Jul 2005
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posted 08-21-2007 11:10 PM
  
Regarding the 'STS-118 Booster Camera Launch Views': Can anyone explain what the heck those two pieces of 'debris' are that seem to come from the nose area and pass under the left wing of the shuttle just after launch? They almost look like large pieces of paper or plastic bags. They are seen in the launch videos from the booster cameras. It's seen in the video segment (camera angle pointing down) as it falls past the wing but in the next segment (with the upward camera angle) it can seen very well coming down from the nose cap area. You can see in the upward camera angle that the debris comes down right after launch as just before you can see the launch tower moving out of the way. |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
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posted 08-21-2007 11:11 PM
They are the covers for the RCS jets and are designed to come off right as the shuttle clears the tower.They are Tyvek. |
Paul78zephyr
Member Posts: 675
From: Hudson, MA
Registered: Jul 2005
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posted 08-21-2007 11:11 PM
Thanks, I've never seen or heard of that before. With all the problem with debris hitting the TPS these covers fall right over the stuff. Have they been doing this since the beginning of the shuttle? |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
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posted 08-21-2007 11:14 PM
Nope, started with 114. |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 08-21-2007 11:42 PM
Per the final report of the Return to Flight Task Group (page 48): Testing is also complete on window impact from debris, including butcher paper, ablator material, foam, Tyvek, aluminum oxide, and small/fast ogive foam. NASA's debris transport analysis suggests that very small ogive foam has the potential to impact the Orbiter windows, but impact tolerance tests indicate that the windows can withstand these impacts without sustaining critical damage. Testing also indicated that butcher paper -- used to cover the forward reaction control system thrusters at the launch pad -- caused unacceptable damage to the windows. As a result, NASA replaced butcher paper covers with Tyvek covers (similar to what large FedEx envelopes are made of) that will not cause critical damage. The Tyvek covers are designed to shed at a low velocity, and as such pose no threat of damage to the orbiter. |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 08-22-2007 12:55 PM
Prior to Tyvek being used, the RCS covers were made out of paper, if I recall correctly. The plan was to blow those off much higher in the ascent of a shuttle then they do today with the Tyvek covers. I believe one of the reasons they do the Tyvek down low now a days is that the old paper could sometimes put a residue on the windows, making photo documentation of debris outside the shuttle potentially a little more difficult. Since the new covers blow off in one piece, it isn't really a problem anymore. The Tyvek covers also have what looks to be a pull tab on them, probably to give them a little more air drag as they fall away from the orbiter. The older covers were flush.I think the aft RCS ports on the shuttle still use paper and you can see those getting puffed and shredded when the SSMEs fire as it looks like the aft RCS ports also fire for about a second during SSME ignition to clear those covers. |
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