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Moonman
2002-Apr-28, 02:11 PM
It's in the British Science Museum in London.

The sign says "Do not touch this exhibit".

Yeah right! It was my 40th birthday, do you think they'll mind? Anyway my hands were all over it (the bit I could reach). Brilliant!

It looks like it's made of wood! Seriously! It's a brown woody colour. Why's that? What happened to the shiny plate that was on the outside?

Also at the Science museum was William Anders Apollo 8 space suit. Nice! I have fond memories of Apollo 8. Possibly the best Christmas I can remember.

<font size=-1>[ This Message was edited by: Moonman on 2002-04-28 10:16 ]</font>

Donnie B.
2002-Apr-28, 04:21 PM
What you see on the outside of the Apollo capsule is the effect of reentry heat. I don't know whether it's actual discoloration of the metal surface, or deposits of vaporized material from the heat shield, or a combination of the two.

It does give the capsule a rather shoddy look, though. I guess esthetics was not the highest priority in the space program.

JayUtah
2002-Apr-28, 05:56 PM
Set fire to your car and see how pretty it looks afterward.

We are accustomed to referring to "the heat shield" as the ablative kiester of the spacecraft, when in fact the entire outer covering of the command module was designed as a heat shield. Obviously the entry profile called for the conical sides of the capsule to deal with less heat than the underside. But it was still subject to enormous thermal loads.

Moonman
2002-Apr-28, 08:08 PM
Are you sure there wasn't an outer plate that has since been removed? The surface of the capsule looked like a combination of wood (for the hatch frame) and a cross-threaded asbestos type material for the rest. I had a good look.

I know it couldn't be wood, but it looked like it.

Sorry if this is not quite conspiracy talk, I just love all things Apollo. I think it must be kinda boring debunking all the time. The HB's must be totally thick.

If it was a hoax then the Russians would have known, it's as simple as that. All other arguments are un-necessary. Unless you believe that they were in on it too!

JayUtah
2002-Apr-28, 10:03 PM
Outer plate, no. Outer covering, yes.

The outer hull of the command module is made of a sandwiched honeycomb material used all the time in aerospace. Imagine something like foamcore, only done with metals. The outer layer of the sandwich is stainless steel (iron, carbon, chromium) though parts may have been Inconel (nickel, chromium, iron).

On top of this was a thin film of shiny aluminized Mylar. This is very similar to the golden film insulation on the lunar module. It's a thin sheet of Mylar, about the thickness of the tape inside a VHS cassette. A very thin layer of aluminum is deposited on it. In the command module's case it is cut into strips and glued in a smooth layer. This is to provide thermal protection during the coast phases. It reflects away sunlight. It provides all the reflective properties of aluminum without the weight.

During re-entry this Mylar layer burns away; it's no longer needed. But it rarely burns away completely. Some strips cling tenaciously to the outer hull. But most were stripped off and kept as souvenirs. You can see a strip of aluminized Mylar that survived Apollo 11's re-entry in the San Diego aerospace museum. In many of the photos of just-recovered command modules you can see how the Mylar strips have peeled away.

During the boost phase the command module is covered by the boost protective cover which is integrated with the launch escape system. This handles the heat caused by aerodynamic friction.

johnwitts
2002-Apr-28, 10:20 PM
I too have seen (and touched, naughty naughty) the Apollo 10 CM, Charlie Brown (or was it Snoopy?) They have it on display with a small rail in front of it, and a polite notice. Touch it? It was all I could do to stop myself from climbing inside the thing. It was a while ago when I went to London, but I seem to remember there being 3 dummies inside which you could see through the windows or the hatch. I remember how small the thing was for 3 people, especially since it was all they had 240,000 miles away from the Earth. I also remember looking at the suit, and thinking it was little more than a big overcoat with legs, That really put the willies up me. They also have a mock LM, which looked small, and some techy bits, which looked fragile, like they were made of paper. All very scary stuff which deepened my admiration for the folks who flew these things by about 1000%.
The heat shield does look kind of 'wooden', but I guess resin does. I could even see some of the Aluminium Honeycomb structure.
In the exhibit is also a J2 engine and it's massive. Next to it is a photo of a Saturn V taking off, and it implies it was using the J2 engines to do it. I pointed out to some amazed people the fact that the J2 was actually one of the smaller engines used on the stack, and they became even more amazed.
I just wish I'd taken my camera...

<font size=-1>[ This Message was edited by: johnwitts on 2002-04-28 18:21 ]</font>

JayUtah
2002-Apr-28, 11:04 PM
They have it on display with a small rail in front of it, and a polite notice.

You Britons are so trusting. I gave the Rosetta Stone a good fondle, albeit on the underside where nothing's written. Compare that to the French. You can't get within forty feet of the Mona Lisa, and it's in a box with a glass front.

I've also caressed the charred remains of Apollo capsule heat shields. (Now I find out it's carcinogenic!) Yes, it looks an awful lot like charred wood. The secret is to make friends with the curators of the smaller museums.

I seem to remember there being 3 dummies inside ...

I'll thank you not to refer to Stafford and company that way. /phpBB/images/smiles/icon_smile.gif

I pointed out to some amazed people the fact that the J2 was actually one of the smaller engines used on the stack

Wait until you see an F-1. It's humbling to see an engine you can park your car in.

roidspop
2002-Apr-29, 05:44 AM
I have a faint memory of a photo of a technician filling honeycomb cells in an Apollo heatshield with a slurry of balsa powder and resin, possibly epoxy. Now that I know it wasn't going to have to do a re-entry at 25,000 mph, I can see how they were able to cut corners like this. /phpBB/images/smiles/icon_smile.gif

Firefox
2002-Apr-29, 05:57 AM
I had the honor of standing inside the restoration room in the Cosmosphere in Kansas while they were cleaning out Liberty Bell 7. I was very tempted to touch it, but I decided not to. I guess I let my fear of contaminating a piece of history get in my way. ::shrug::


-Adam

Moonman
2002-Apr-29, 08:41 AM
Thanks again for more great information.

I have a picture postcard of the Apollo 10 capsule on my desk in front of me. I understand what I am seeing now, what I thought was cross-threaded asbestos is the honeycomb structure that you mentioned. It makes sense now.

JayUtah
2002-Apr-29, 03:10 PM
I guess I let my fear of contaminating a piece of history get in my way.

Fish have been pooping in it for forty years and you're worried about contaminating it with your hands? /phpBB/images/smiles/icon_smile.gif

JayUtah
2002-Apr-29, 03:15 PM
... is the honeycomb structure that you mentioned.

We still use that honeycomb stuff in aerospace. If you take the aileron off a 737 or an F-16 and hacksaw a corner off of it, you'll see two sheets of aluminum about 3/16 inch thick and the inside will be filled with that honeycomb. To make the command module heat shield they just got a bunch of that honeycomb and filled the cavities with resin.