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Bettina

space shuttle

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I am always interested in watching the shuttle launches and landings and now we have another foam problem. I understand why the foam is there, but what I don't understand is why they can't add some type of nylon netting over it to keep it from falling off if it breaks its bond.

 

I understand the high forces, tremendous speeds, etc, but I also know that nylon netting (or other material)can be made pretty strong and light.

 

What am I missing.

 

Bee

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It's still extra weight. In the first launches, they had white paint over the foam layer, and that added several hundred pounds of weight to the tank. And that was just paint.

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nylon netting would probaly be lighter than paint i dont know why but i think it would. But it might affect it areodynamicaly or even maybe a lightweight nylon netting would just get obliterated by a high speed piece fo foam.

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i still don't see how nasa can continue to ignore the engineering genius of duct tape. just slap it over the crack and it's good to go.

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In the first launches, they had white paint over the foam layer, and that added several hundred[/i'] pounds of weight to the tank. And that was just paint.

OUCH! That's a lot of paint!

 

However, there must be something they can do to solve the foam problems. It really is getting quite repetitive, and I'd hate to see the space program halted over something as (seemingly) trivial as that.

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What if they take the reverse approach, and make it *more* likely to fall off, but in smaller chunks? Kinda like how tempered glass breaks into little cubes rather than big sharp shards. If the foam is designed to fall off in small bits that can't do any damage, the problem is solved, possibly with little if any weight penalty.

 

Mokele

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One thing that may not be obvoius is the amount of fuel the Shuttle has to carry to get to orbital speed. One and a half million pounds, mostly solid propellant to get 50,000 pounds of payload to orbit. orbit.http://en.wikipedia.org/wiki/Space_Shuttle

 

Or 30 pounds of fuel per pound of payload (or extra paint etc.).

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I remember a professor brought in a piece of the same foam to show in a class. That stuff is ridiculously soft and brittle. No way a netting would help...probably damage it further...plus nylon doesn't have that high a temperature resistance.

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What "foam problem" are you refering to? They expect foam WILL fall off during launch (no way to prevent it), its all about where it comes from, how massive the foam is and how far into the flight it falls off. In this flight they had no foam fall off that was before 2m:15s into the flight so it was of no concern. What did fall off was also small enough that it would likely not have caused issues even if it had fallen off earlier.

 

"Netting" would be pretty heavy im sure but the real issue is aero dynamics. Every "strand" of the net would cause drag and it would be yet another thing that could fall off and cause problems. Also, most pieces that do fall off are so small netting wouldnt prevent it.

 

The old white "paint" was scrapped for Cost (of the paint) and weight.

 

This tank also had something like 95% of its foam applied over 3 years ago (before Columbia even) and very little was actually changed. (mostly the PAL and ice frost ramp areas)

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This tank also had something like 95% of its foam applied over 3 years ago (before Columbia even) and very little was actually changed. (mostly the PAL and ice frost ramp areas)

 

Um, no, it has none of the old foam. It's not even the same tank. The space shuttle and solid rocket boosters are re-usable, but the external tank is disposable, breaking up over the Indian Ocean. There's a new tank every launch.

 

 

No thoughts on my idea of specially modifying the foam so it comes off in predictably smaller (therefore harmless) chunks?

 

Mokele

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Um' date=' no, it has none of the old foam. It's not even the same tank. The space shuttle and solid rocket boosters are re-usable, but the external tank is disposable, breaking up over the Indian Ocean. There's a new tank every launch.

 

 

No thoughts on my idea of specially modifying the foam so it comes off in predictably smaller (therefore harmless) chunks?

 

Mokele[/quote']

 

Watched the interviews over the last few days? A reporter asked about foam loss and the shuttle director specifically stated that only about 5% of the foam was changed and that this particular tank was built and "foamed" before Columbia even lifted off.

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Watched the interviews over the last few days? A reporter asked about foam loss and the shuttle director specifically stated that only about 5% of the foam was changed and that this particular tank was built and "foamed" before Columbia even lifted off.

 

Judging by only those words, there is absolutely no evidence that the tank has been used. And I believe Mokele is right about not reusing tanks (I'm actually almost positive he is). That doesn't say that the tank wasn't manufactured pre-Columbia, it just means it hasn't been used.

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...I'd hate to see the space program halted over something as (seemingly) trivial as that.

Unfortunately, there is no such thing as an engineering no-brainer.

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Judging by only those words, there is absolutely no evidence that the tank has been used. And I believe Mokele is right about not reusing tanks (I'm actually almost positive he is). That doesn't say that the tank wasn't manufactured pre-Columbia, it just means it hasn't been used.

 

Right, they dont reuse the tanks, they partially burn up on re-entry and fall into the Indian Ocean and probably end up forming reefs..

 

What I was saying is that most of the foam on the tank Discovery used was applied to that tank pre-columbia (all the robotically applied foam which is 90+% of the foam was not changed). The "changes" where very small percentage of foam on the ramp areas (removing a ramp and changing some of the other small ones).

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It seems that the shuttles will be replaced fairly soon anyway. Also, if you ever get the chance, come to Brevard and watch the shuttle launch. It is very exciting to watch the shuttle in the sky (not on tv) and look for the rocket boosters falling.

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What's the space shuttle being replaced with?

 

wars in the Middle east...

 

j/k :cool:

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It's still extra weight. In the first launches, they had white paint over the foam layer, and that added several hundred[/i'] pounds of weight to the tank. And that was just paint.

 

Was that back in the lead paint days by any chance?

 

Regardless shuttle tech is out there, but NASA lacks funding. If you really want to see more space missions let your government know. Currently, as mentioned, a large portion of your funds is going overseas and that's not likely to change anytime soon.

 

Regardless you need to let them know or they won't continue the program. It's already on it's last legs.

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It was back in the 80s, and I have no idea if they used lead paint or not.

 

I think he was making a joke;)

 

Seriously though, what will NASA use to get into space when the shuttles are decommisioned? I presume the manned space programme isn't being shut down? That would seem a very retrograde step.

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