Quote from NASA website documents

... photograph of the workshop's exterior, filmed during the first crew's flyaround inspection,
clearly shows the discoloration and blistering suffered by the gold foil cemented to the skin of
the workshop of the space station (Skylab) from prolonged exposure to the Sun."
p64.jpg Taken from this page on the NASA website.

http://history.nasa.gov/SP-400/ch4.htm

Would have set this message to carry the image directly but it seems Ol' Phil has set up the forums to obstruct that sort of thing. Stil you should go ahead and click the link to see the picture. If it was me I'd have condemned the station and aborted the mission. Of course I'm kind of chicken about boarding a spacecraft as blistered and beat up as that.

SAMU



<font size=-1>[ This Message was edited by: SAMU on 2002-07-06 21:12 ]</font>

My mom had a 79 Vega, a car famous for rusting in the show room. I drove it quite a bit in spite of the rust, the leaks, the frequently sticking gear shift, and the ever present threat of the aluminum engine block melting down. Sure, I would have prefered a brand new mustange, but sometimes you just have to make due with what you have available.

<font size=-1>[ This Message was edited by: Espritch on 2002-07-06 22:55 ]</font>

Your point being...?

Actually, if you read the FAQ, it's clear on how to post images. I posted one in this very forum just this morning.

And your accusation of my doing this to "obstruct that sort of thing" wins you no points. What purpose would posting that statement make? And indeed, since it's wrong, it doesn't carry much weight either way.

Are you still trying to argue that Apollo 13 would have gotten hot instead of cold? If so, fast-forward to the chase.

Why did Skylab get hot and Apollo 13 get cold when they both lost power?

Is that it?


<font size=-1>[ This Message was edited by: Jigsaw on 2002-07-07 01:21 ]</font>

That's a good URL, and that's pretty much the answer. Thermodynamics is not a matter of simple comparisons and intuition.

The gold foil on Skylab was not intended to be the outer layer. It was intended to be the intermediate layer between the outer thermal and micrometeoroid shield and the inner skin. As an intermediate layer, it shouldn't have been exposed to direct sunlight. But it was, since the outer shield was ripped off during the launch.

Gold has terrible properties for radiant heat transfer; it absorbs a great deal of incoming radiant energy without re-radiating much of it away. As a result, its equilibrium temperature is much higher that, say, aluminum. The outer surface of the command module was aluminized mylar, designed to reflect away as much radiant energy as possible.

In the commentary track to the Apollo 13 DVD, Jim Lovell commented on the cold. He said something to the effect that, with all the electronics turned off, it got cold rather quickly. He made it pretty clear (to me at least) that it was the heat generated by the machinery that was keeping them all warm.

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

<a name="20020707.3"> page 20020707.3 aka He,He a `79 Vega [Bound]
On 2002-07-06 23:13, The Bad Astronomer wrote: To: 6 AHAU 14 TZEC
Yeah, its the Last day of the Mayan Calander
Tomorrow A new one begins
With Corn once again of course






Your point being...?

The kid was Stuck with a `79 Vega
and HE wanted a NEW Mustang that
would go from 0 to 60 in Less than
an hour! Can you blame "Them" ..
I mean really! Not to mention the Tranny'
oh well back to AS.. oh never mind.
3:08 A.M. PST

On 2002-07-06 23:45, JayUtah wrote: To: 3:10 A.M. PST
Are you still trying to argue that Apollo 13 would have gotten hot instead of cold? If so, fast-forward to the chase.

No, NO, no run the Vidio :"_to the MOON_":
backwards at .707 speed from the part where
(already on the surface) the video camera
Pans the APEins & then Zooms So you get
UN.Zoom/1.4 ReSpan [R-L] and 4get politics
for 11 minutes ..pLeee$e ?

He made it pretty clear (to me at least) that it was the heat generated by the machinery that was keeping them all warm.

All one has to do is look at the ECS block diagrams to realize that heat from the electronics was meant to be transferred to the cabin air.

A significant amount of post-powerdown heat was the greenhouse effect of sunlight shining through the cabin windows onto surfaces inside the cabin. When the crew put up the window shades to try to sleep, that's when the temperature really plummetted.

I don't know what SAMU's point is, or even if he has a point other than pointing to the terrible condition of Skylab's paint job. But a few months ago in a thread buried deep below he tried to argue that Apollo 13 should have gotten hot instead of cold after being powered down, and that since NASA claimed it got cold, that meant Apollo 13 had been staged somehow to cover up an ulterior motive.

Here's the prior thread, if it's applicable:

http://www.badastronomy.com/phpBB/vi...ic=111&forum=3

Very funny. [img]/phpBB/images/smiles/icon_smile.gif[/img] Wow! Hub made a Joke and I actually understood it!

I just noticed that I am now a Bad Apprentice instead of a Bad Newbie. I guess that explains why I'm beginning to understand Hubish. [img]/phpBB/images/smiles/icon_biggrin.gif[/img]

Jay, it seems to me that the link SAMU gave actually does a good job of disproving his Apollo 13 theory:

1. Skylab's design included special coatings and insulations, carefully located on the assumption that the vehicle would be in an attitude in which the solar panels faced the Sun most of the time. When this attitude was changed for long periods to reduce solar heating in the workshop, temperatures in the spacesuit cooling water loops decreased until the water was very close to freezing. Frozen water could have broken lines but, even more serious, water freezing in the heat exchangers would have caused failure of the primary coolant system. This system was vital to the cooling of electrical equipment and to providing a comfortable environment for the crew.

There we see that, depending on the attitude of the spacecraft, the interior could be very warm or very cold. Also, it would be nice if SAMU would compare the "color" (for want of a better word) of Skylab with that of the CM/SM stack of Apollo 13

Let me get this straight.

Apollo 13 is in roughly thermal equilibrium with its surroundings with heat absorption from the sun and heat rejection to deep space. The heat producing electronics are shut down and things get hotter. This has got to be one of the worse arguments yet. This violates both the first and second laws of thermodynamics.

From the first law of thermodynamics, which is essentially the conservation of energy, to have a new hotter temperature, more energy would have to added to the Apollo CSM, CM and LM. Where pray tell does this energy come from?

Since there are no other sources for this energy, it must come from the deep space environment. This violates the second law of thermodynamics. Heat flows from hot to cold not the other way around.

In other words, when you pour yourself a cup of coffee, it cools off, it doesn't heat up.

Where pray tell does this energy come from?

According to SAMU's original argument, from the sun. That is, he argued that since the radiators were turned off, the heat from the sun which those radiators were rejecting was now building up in the spacecraft.

I won't rehash the original argument since it's there for everyone to see and I'm not sure SAMU is trying to resurrect it.

Well at least some thought is behind that argument.