Aerospace Blog

Hey, is that duct tape that is on the external tank to fix the leak?

Great pictures and thanks for sharing!

Britain has had a go at this too. Here's a photo of the first Reliant Robin to go into space:

That would be an interesting way to go. <Splutter>

Surely...

That isn't a rusted main tank? Must be paint. NASA wouldn't let rust hang out like that...or would they?

j.

The orange hue is very likely from the polyurethane foam insulation covering the main tank. I wondered why NASA tolerated the bits of foam breaking off from the tank during the launches and look what happened to the Columbia accident in February/2003. I sent an e-mail to NASA some time back suggesting that they cover the foam with a sort of a metallic or plastic skin and did not hear from them. Do these main tanks get reused ?

Now that the shuttle missions are expected to stop at the end of 2010, who will be taking care of the transports to and from the International Space Station and what will be the next phase of manned missions for NASA ?

The orange is the native color of the foam. If you remember the very first launches of the Shuttle the tank was white. That was because it was painted.

NASA stopped painting the tank to save weight! Can you imagine the weight of a plastic skin over the tank?

Then again, maybe if we collected all those plastic thingies that hold beer cans together... naw!

Surely you jest?

Foam being lighter than a coat of paint?

Surely chicken wire embedded in the foam can't add that much weight?

j.

Paint is no longer applied to save weight. That is the truth. From Wikipidia, "The original ET is informally known as the Standard Weight Tank (SWT). The first two, used in STS-1 and STS-2, were painted white to reduce solar heating and cryogenic boil off. Because this did not turn out to be a problem and to reduce weight, Lockheed Martin ceased painting the external tanks beginning with STS-3, leaving only the clear primer over the now-trademark rust-colored insulation, saving approximately 272 kg (600 lb) of weight."

Anything you add as a lattice network will add weight. Paint is a lot lighter than chicken wire.

However, let's give it a try. The length of the external is 153 feet. It is 27 feet in diameter for a surface area of 14,123 square feet using the formula Surface Area of a cylinder = 2∏r^2 + 2∏rh.

I looked up rolls of chicken wire and the mass works out to be about 0,11389 pounds per square foot.

Multiplying 14,123 by 0.11389 = 1,608.5 pounds.

The current going cost per pound on the Shuttle to get to LEO is about $8500 per pound. Each launch would add $13.67 million.

Maybe strands of carbon fiber would work. I am sure all of that has been put on the table a number of times.

However, the big show stopper is cost and time. NASA does not have an infinite budget and there are only 10 more launches scheduled for the Shuttle then it becomes a bunch of museum pieces around the world.

It does not make sense to try to design, test, and deploy such a system with the end of life for the Shuttle fleet about one year away.

I wasn't looking forward but rather backward at the insanity of glued on tiles which to me long ago looked like an invitation to disastrous failure.

The pictures, the first time I have seen close up detailed shots of the boosters and the vehicle, show what looks to me as really rough work and crude configuration on what I would have thought would be the clean smooth lines we see on things like fighter aircraft or big airliners.

j.

<....taking care of the transports to and from the International Space Station....>

That assumes it will stay in orbit....

I hadn't thought of that.

Actually I had been waiting, all the years since they started to design the thing and talked about cementing on ceramic tiles, for just the accident that happened. By nature those tiles are very fragile.

Surely, albeit more expensive, there must be other means to produce a high temp resistant skin.

As for the foam I would think they would embed in the foam something like chicken wire so that anything that does break off would be infinitesimal.

j.

I forgot to answer all of your questions.

1. The main tanks are not reused.

2. The US will rely on Russia to supply all transportation until the first manned flight of Orin scheduled for late 2014.

I very much doubt it will be ready by then, so at least 5 years before we return a crew to space via USA power.