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What's up with the Space Shuttle?

mummymonkey said:
I see. The current spacecraft is safe then?
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From the above article:

NASA does not expect to make a final decision until Sunday or so on whether Discovery can safely return to Earth. That is how long it will take to analyze all the data from the more than 100 cameras that tracked the liftoff, scores of sensors embedded in the shuttle wings, the laser inspection, and pictures from space.
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Hopefully there's no ugly damage lurking due to debris or other factors. They'll know more in the next few days.
 
I remember reading here a few years ago that the old type of foam NASA used was much more durable, but that they had to stop using it because it used a number of environmentally unfriendly substances in its manufacture.

Assuming that all that's true, given that the shuttle makes relatively few flights, and given that it's presumably going to be pensioned off in the next few years, should NASA consider returning to their old-style foam?
 
richardm said:
I remember reading here a few years ago that the old type of foam NASA used was much more durable, but that they had to stop using it because it used a number of environmentally unfriendly substances in its manufacture.

Assuming that all that's true, given that the shuttle makes relatively few flights, and given that it's presumably going to be pensioned off in the next few years, should NASA consider returning to their old-style foam?
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That's an interesting question. At yesterday's press briefing one of the reporters stated that three of the the last four shuttle launches involved some amount of foam insulation debris and the fourth was a night launch. He asked if something had changed at some point. The panel didn't mention any change in foam chemistry. I wonder where you look to find out about that.

It's hard to be sure about that kind of thing because the ET is never available for examination after it is used. If they don't see foam damage between liftoff and separation they have no evidence that it happened. This launch is the first where they have had cameras in place to actually monitor for this so they may just be detecting something that has been an issue all along.
 
I think I found it. This article from May, 2003, indicates that a change was made but it's not clear exactly when.
Environmental requirements requiring removal of freon from the process for spraying the foam insulation onto the tank. NASA has said that the freon-free application method resulted in foam that initially did not adhere to the tank as well, but changes were later made to strengthen the bond of the environmentally friendly foam.
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It's interesting that they specifically mention problems with adherence. The article also states that foam had been seen coming off the tank in 71 launches to date but there is no mention of a correlation between foam/application changes and frequency.
 
I wonder how environmentally unfriendly an exploding shuttle is...

(Not to mention, astronaut unfriendly...)
 
Blondin said:
I think I found it. This article from May, 2003, indicates that a change was made but it's not clear exactly when.
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From here:

The "new" foam containing HCFC 141b was first used on the liquid hydrogen tank aft dome of ET-82 and flew on STS-79 in 1996. The foam was implemented on the tank's acreage, or its larger portions, beginning with ET-88, which flew on STS- 86 in 1997.
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this foam that were talking about...when I think foam I naturally think of packing foam inside a cardboard box...lightweight stuff. How dense is this stuff that it damages the tiles? or is it lightweight but just hitting it at such a high speed?

and I've trying to find a link that shows the speeds of the shuttle at various points in its journey to orbit. Would anybody know of a source??
 
I had posted in another thread..

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I heard one of the talking heads say something like:

" This new development will not cause Columbia to cut the current mission short and return to Earth early .. "


Does anyone else see the faulty reasoning here ?
 
The shuttle program is a dead-end. The sooner its stopped the better (after doing one last overhaul of Hubble)
 
Diogenes said:
I had posted in another thread..

----------------------------------------------------------------------------
I heard one of the talking heads say something like:

" This new development will not cause Columbia to cut the current mission short and return to Earth early .. "


Does anyone else see the faulty reasoning here ?
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Aside from the fact that it's Discovery that is currently up in space...
 
HarryKeogh said:
this foam that were talking about...when I think foam I naturally think of packing foam inside a cardboard box...lightweight stuff. How dense is this stuff that it damages the tiles? or is it lightweight but just hitting it at such a high speed?
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The piece that struck Columbia during takeoff was only a pound and a half or so, but it impacted the leading edge of the wing surface at roughly 500mph on an area of carbon paneling that's something like 10mm thick or less. When they were able to better duplicate the scenario in a later test, the result immediately dropped jaws (literally) when it produced a 16x16" hole in the RCC panel (more here and here). Such a possibility in this case unfortunately went largely unconsidered beforehand.

Pretty easy to see why the unresolved foam/debris issue constitutes a substantial hurdle.

and I've trying to find a link that shows the speeds of the shuttle at various points in its journey to orbit. Would anybody know of a source??
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There's an overview here, and if you want more detail, this contains a great deal.

*edit: doh, typo
 
Armchair aerospace engineer I'm not. Can't help but wonder though if the idea of bringing back the white paint for the ET (like in the good ol' days) would hold any merit? Sure, it'd add weight which would cut down on payload capacity, but if it'd seal out moisture and help keep the foam in place... slap some on there.
 
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