Electronics require currents. Agreed? ok, fine then. In order to have currents not create heat, you need a super capacitor. Super capacitors in general require them to be cooled to temperatures close to the absolute zero point (atthis point, their electrical resistance gets close to 0, and therefore so does their heat producing). The process of cooling close to the absolute zero takes loads of energy and produces loads of heat in itself. In total -which is relevant for a self-contained spacecraft- it costs way more energy and generates way more heat than just have the electronics run at their "native" temperature.

therefore, electronics, perfectly installed and designed, will generate heat. Quite some heat indeed. My class A preamplifier heats my room, i'm serious about that. My PC generates loads of heat. Like Jay, I got serious burns from touching a bare, running processor. This heat is simply a result of necessary currents running through materials which will have an electrical resistance in any practical case.

We could not and cannot construct a spacecraft using super conductors only.

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I can download it right now, so the link is ok.

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To the regular visitor of internet bulletin boards it is clear that it's an excellent idea your parents get to choose your real name.

The more heat that is produced by electronics, the lower the temperature of equilibrium will get when they switched off electornics in A13. So the craft would have gotten very cold, which it did. Note that the cooling of A13 was largely passive, i.e. you could not switch it off because it was just a product of the materials used and passive radiators. All designed to make a comfty equilibrium when all electronics ran and produced heat, so cooling too much when the electronics were switched off.

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The electronics inside apollo did not work in a near vacuum but in the cabin's atmosphere. Even if electronics are placed in a vacuum, the electrical currents running through conductors with electrical resistance will generate heat.

What is efficient? Electronics require certain currents. And those current generate heat. a more efficient system will draw less current to do the same task and hence produce less heat, but you'll always have a required amount of "juice" ie current to run a thing, hence a basic amount of current you simply need. And hence a basic amount of heat. So whether the apollo electronics were efficient or not, they will have produced heat (as said, super conductors are out of the question) The cooling system was designed for the heat the electronics produced, A13 switched the electronics off, no heat, same amount of cooling, hence too cool craft.

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To the regular visitor of internet bulletin boards it is clear that it's an excellent idea your parents get to choose your real name.

Your question has been satisfactorly answered. Your refusal to accept that answer doesn't change the fact that it HAS been answered.

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Not at all. You fail to realise that the electronics weren't all in the vacuum of open space, but were inside the cabin.

Electronic components generate a lot of heat, and that heat would have warmed the cabin of the spacecraft. Switch off the electronics and that heat source disappears. That really is elementary physics.

But the real question seems to be why an unpowered spacecraft in sunlight gets cold and not hot, in which case most of the discussion about heating and cooling in a powered up spacecraft seems a little beside the point.

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"The very powerful and the very stupid have one thing in common: They don't alter their views to fit the facts, they alter the facts to fit their views." The Doctor, Doctor Who: The Face of Evil.

I have yet to see the material in the link posted. Radiators that rely solely on radiative transfer and conduction as thier method of removing heat require a large surface area, and in the absence of a gas or liquid to convect heat away the surfaces must not be arranged so that infa red emmenating from them is simply not reabsorbed into an adajacent surface. In other words the geometry that could work is quite limited in scope.
Like I said, I can't download the file referenced above.
I do not accept Wikipedia as a reliable source of information because of its dubious way of compiling 'facts' (people just post information there and represent it as fact). However, the information you linked is essentially correct. It doesn't make any difference. The Apollo Command and service modules I saw on the launch pad were not highly polished either, they were painted.


I think my firewall has a problem with the link , it simply won't download.
As I recall the IC technology available at the time was about 50% efficient. That means the other half of the electricity running through this particular circuitry that was "lost' was done so in the form of heat energy.

That depends on the requirements and the available technology.



I'd have to disagree. I've seen a lot of information presented here on Apollo and have often used it as a launchpad for my own research. Nevertheless, it isn't our responsibility to do your research for claims that you have made.



What "unsubstantiated process" are you referring to? Heat rejection by radiation is an extremely well substantiated process, and you have already mentioned it yourself. Also, a "radiator" that works primarily using convection is quite different from a true radiator that works by radiation.



No! There is a glycol evaporator system in addition to the radiators for peak heat load situations, but the radiators are the primary heat rejection system. They work by radiation. [/QUOTE]

Well then Houston, we have a problem. The radiator you describe would require a large surface area composed of fins or ribs arranged in such a way that the heat radiated from one surface would not simply be reabsorbed by an adjacent element. It would also need to be visable on the outside of the spacecraft to work with any efficiency, and always kept on the shaded side of the craft. SOmething stinks here, doesn;t it? The command module was POLISHED? Not the ones I saw on TV.

Look at the attached image showing an Apollo CSM.

The body is metallic and reflective. The conical section at the front, the inhabited command module, is highly reflective, almost mirror-like.

The white band along the bottom end of the cylindrical section and the smaller white rectangles along the top of the cylinder just below the command module are the radiator panels. They do not have a problem of radiating their heat to an adjacent surface because they have no adjacent surfaces. They are on the outside of a cylinder facing into space. They run around the entire circumference of the spacecraft, so at any one time half of them are always on the shaded side of the spacecraft.

Attached Thumbnails

 

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"The very powerful and the very stupid have one thing in common: They don't alter their views to fit the facts, they alter the facts to fit their views." The Doctor, Doctor Who: The Face of Evil.

The ones you saw on Tv on the launch pad, had the BPC or boost protective cover over the command module. It's a conical, white painted cover that protects the command module during ascent and when the escape tower would be fired. Once in space, the BPC was removed and the naked, shiny command module showed.

Apollo block 1 service modules were painted white but not used manned in space. Apollo block 2 service modules had the shown silver exterior. These were used for the manned flights including those to the moon.

Again a point in case of why apollo specifics are a necessary part of the answer to your question.

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What was the error? By the way, I assume you have Acrobat reader installed?

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Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

True, SOME of them were inside the crew cabin. That doesnt change the fact the heat they produced had to be shed in the space enviroment.

Yes it is, and later I promise you will see why what you just said re enforces my arguement. First of all, a spacecraft heats up when in our vicinity of the solar system from the Sun alone. What temperature is the solar observation satelite running at?

It wouldnt get cold, thats the whole point.
Even if the energy input from the Sun were minimal in space and NOT greater than on the surface of this planet (which it is, by the way), with all the heat being produced by the electronics and hardware as well as the Astronauts themselves, radiative forcing cannot possibly explain how livable temperature was maintained. It is that simple. Your link is either busted or bogus, I'm not sure which. I seriously doubt it's on my end, I can download PDF's from other sources with no problem, I tryed it to make sure.

I bought this computer in January, and yes it does have Adobe Acrobat Reader.

It said "done" at the bottom of the page yet data was still be transfered. It finally locked up my processor at 100%, and I had to shut it down manually, with the power button.

I tried the link and had no problem. I'm viewing the PDF right now. Front page says "NASA TECHNICAL NOTE - NASA TN D-6718"

If you don't have Acrobat or Adobe Reader installed as a plug-in for your browser, you may have to right-click the link and choose "save as", then load it manually.

BTW, here's another good photo showing the highly reflective surface of the CM:

http://www.solarviews.com/history/SP-350/i10-5.jpg

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"I had a hand in Tom Morrow's kiester."
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"The only physical proof nasa has that they landed men on the moon is 840 lbs. of rocks"
-straydog02

The Earth heats up from the Sun alone. What temperature is the Earth running at?

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You have numbers to back that up, of course? You have made a quantitative argument. Provide the data to support it, please.

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"The very powerful and the very stupid have one thing in common: They don't alter their views to fit the facts, they alter the facts to fit their views." The Doctor, Doctor Who: The Face of Evil.

Then show the numbers. You make quantitative statements, in order to give them merit they should be backed up by numbers.

Plus you argue on one hand that the electronics (and astronauts and sun) produced so much heat that the capsule would get too hot for the astronauts, but on the other hand that switching off the electronics apparently cannot explain the capsule getting cold as happened on A13. So please give numbers, to show how you "rhyme" these two statements.

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The link itself is fine, I was able to download the file.

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To the regular visitor of internet bulletin boards it is clear that it's an excellent idea your parents get to choose your real name.

Try saving the file and opening it from Acrobat Reader.

Sometimes I have problems running Acrobat in a browser, and the plugin can sometimes chew up cpu time. Right click on the link and see if you can save the file to disk. If that works, open it directly in Acrobat, rather than going through the browser.

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Disclaimer: Avatar is not an official NASA image and does not imply any specific interplanetary or interstellar capability.

The Leif Ericson Cruiser

The temperature of an object in space at the earth's distance from the sun depends on two factors, albedo and emissivity, which both in turn depend on the physical make-up of the object. Pick the right values, particularly for albedo, and you can get any temperature within a wide range. For instance, a matt black object will generally run hotter than a mirror-finished one. Why do you have a problem with this?

Many satellites have passive temperature control achieved by selecting the right surface finishes.

Jason's link works for me too. Must be something to do with your browser. Have you tried saving the pdf to your machine and then opening it?

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"The truth may be out there, but lies are inside your head" Terry Pratchett

Like the others mentioned, if it's that simple please enlighten us some more concerning the mathematical equations that led you to this obviously undoubtedly conclusion.

Whether a spacecraft ends up being hot or cold in a vacuum (which is a perfect conductive and convective insulator) has a lot to do with the radiative balances on it's surfaces, and the wavelengths being emmitted and absorbed. (And the amount of heat being generated internally).

You can have a sunward facing radiator on your spacecraft, as long as it reflects wavelengths in the visible regions where the sun is putting out the most energy, and absorbs (is blackbody) in the infrared regions where the spacecraft, due to it's temperature, will be radiating.

If your spacecraft was painted black, it would get pretty dang hot, even with no internal heat sources. If it is very reflective in the visible and near-infrared range, it'll get very cold.

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OK, let's break this down then.

We have seen from Grant's equation on page 2 that an object in space covered in highly reflective material as the Apollo spacecraft was will not heat up above freezing due to incoming solar radiation. Sunlight is therefore not enough to create an overheating problem in the spacecraft.

Does the cooling system work as advertised? Well, for the Apollo 13 question that this thread began on this is not an issue because the cooling system, along with everything else, was shut off during the coast home. For everything else it is an issue, because if the cooling system could not operate as it is said to have done then the whole of Apollo becomes suspect.

On Apollo 13, then, it seems the only source of heat inside the cabin was the astronauts themselves and whatever sunlight may have come in through the windows to warm the interior.

So, the key questions seem to be:

What equilibrium temperature will an unpowered Apollo spacecraft on a translunar or transearth coast reach?

How long will it take an unpowered Apollo spacecraft with three men inside to reach this temperature, or what temperature could the cabin interior reach during the time the spacecraft was powered down?

Can the Apollo cooling system work effectively to maintain a comfortable environment inside?

Assuming that you have performed your own calculations to arrive at your previously stated conclusions, IDW, what do you have as answers for the first two questions, and why do you believe that the answer to the third is 'no'.?

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"The very powerful and the very stupid have one thing in common: They don't alter their views to fit the facts, they alter the facts to fit their views." The Doctor, Doctor Who: The Face of Evil.

What parts of the cooling system do you mean were shut off?

They couldn't change the shiny exterior. Could they close the radiators? What else?

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To the regular visitor of internet bulletin boards it is clear that it's an excellent idea your parents get to choose your real name.

If I can just jump in here real quick and ask for a clarification...

Interdimensional Warrior, I get the feeling you're implying that there's no way the command and service module spacecraft could work, at all. That there's a fundamental design flaw that would fry the astronauts after a short time, no matter what.

If you're NOT saying that the SM/CM ship was unworkable, please correct me.

If you ARE saying that, then that would imply that Skylab and the Apollo/Soyuz missions were also faked, and would also imply that the Soviets were more than happy to go in on a faked mission with the U.S. Is that what you're saying?

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See? Because of me, now there's a warning. -Homer Simpson

On the other hand, I would ask people, where possible, to stop nannying this discussion topic on a public discussion forum.

People, feel free to contribute what you wish to contribute. If you think you know an answer, provide it. If you have a question, ask it. Want to comment? Do so. Go about your normal BAUT business.

Interdimensional Warrior is not a special member.

This topic is not special.

Edit: JayUtah... now Jay is special, but not in that way. But, Jay answers this well, ahead (here). And, he rightly points out that there is a discussion topic, Wondering if I could set up a one on one..., where one might try to request special behavior for BAUT participants in these IDW topics, and it's something I should have will pre-repeat, for late-comers. (Time travel sure messes up language.)

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http://www.tsgc.utexas.edu/archive/s...ms/thermal.pdf

An interesting site, lots of "not so basic" math. I was comparing some of the figures with the data in SMAD, Wertz and Larsen...seem to match up pretty well.
Between radiators, sublimators/boilers, surface coatings and PTC, it seems like thermal control was understood and managable.

For more information on why the CSM looked "painted" while on the pad, check here or here or here...or just google Apollo LES boost protective cover.

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"Think of the rivers of blood spilled by all those generals and emperors so that, in glory and triumph, they could become the momentary masters of a fraction of a dot." --Carl Sagan "Pale Blue Dot"

Agreed. Sorry Obviousman, but my answer is (still) no.

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With smiling [faces] lyin' to ye' everywhere ye' go
Turn to, and put out all your strength of arm and heart and brain
And like the Mary Ellen Carter, rise again.

The current discussion has led me to a question for IDW.

If you, IDW, can actually run the numbers and figure out that the Apollo CM's couldnt work, why couldnt every non-NASA engineer in the last 40 years also figure it out?

It seems to me that it is 'put up or shut up' time IDW. Please provide some actual numbers where you figure out from first principles that the Apollo CM's couldnt work as advertised, including the Apollo 13 module after it was damaged.

Before you martyr yourself, please note that 'put up or shut up' is a turn of phrase that simply means provide your counterproof or we can consider this question reasonably answered and move on to the next.

I've done as promised, and stayed out of this until I saw a few points which I felt hadn't been addressed, or needed reinforcing. So I'll post this and than re-lurk.

it is a wide spectrum of frequencies of EMR and non EMR radiation, all of which can and do cause heating of metallic surfaces when impacting them

Theoretically true, but not practically so. The EM energy received from the Sun is strongly peaked in the visible and near-visible infrared; the energy distribution is approximately 7% UV, 46% visible, and 47% near-visible infrared. [SMAD 3] Other EM energy is pretty much down in the noise. Particle radiation does not contribute significantly to heating of a spacecraft.

What this means is that the spacecraft thermal enginers, need only concern themselves with relatively narrow bands of incident energy from the Sun, and there are a variety of materials and finishes to deal efficiently with this. IR radiation from the Earth is another matter, but the Apollo spacecraft didn't hang around the Earth very long, and for the case you're arguing (A13 in translunar flight), Earth IR was a minor factor.

An automotive radiator is not essentially different than the one you describe.The main difference of course is that air moves over the cars radiator and there is no air in space, so your radiator depends on shedding radiant heat and the cooling created by some as of yet unsubtantiated process.

An automotive "radiator" is fundamentally different from a spacecraft radiator, and since you seem to grasp the difference between radiation and convection I am puzzled as to why you would make such a statement. You correctly stated that a spacecraft radiator needs to avoid reradiating back to the spacecraft. Look closely at an automotive radiator. The vast majority of the surface area is composed of the small convolutes, which are ranked in numerous parallel rows.

Also, there no unsubstantiated processes. A spacecraft in flight is cooled by radiation, except in the cases where an evaporative or sublimative cooler (such as those already discussed) is employed. That's it. There's nothing else.

What I need to know is two things.
1) How much heat was produced by the electronics under normal conditions.
2)How much heat could be removed by Jays' cooling apparatus.

Two unknown variables, without which we cannot continue.

I will attempt to get the data for you, since you seem to be having issues downloading the data; it may be due to your Internet connection - I've had similar problems with large files, even over broadband connections. But, since you don't have any of the data, how is it that you're so confident that there's a problem, as in -

Well then Houston, we have a problem. The radiator you describe would require a large surface area

How large?

composed of fins or ribs arranged in such a way that the heat radiated from one surface would not simply be reabsorbed by an adjacent element. It would also need to be visable on the outside of the spacecraft to work with any efficiency, and always kept on the shaded side of the craft.

Already discussed - the radiator forms part of the cylindrical and conical surfaces. Spacecraft structures themselves radiate; the question is how efficiently heat is transferred to them from the interior, and what their absorptivity and emissivity are. That's where the various materials and coatings come in. Moreover, as already explained, there were always radiative surfaces exposed to deep space.

SOmething stinks here, doesn;t it? The command module was POLISHED? Not the ones I saw on TV.

Asked and answered. Since the lunar-mission CMs did indeed have a polished aluminum surface, do you retract the claim that "something stinks"?

Even if the energy input from the Sun were minimal in space and NOT greater than on the surface of this planet (which it is, by the way),

But the entire Earth includes the atmosphere, and the energy flux on any given area of the entire Earth is the same as for a spacecraft orbiting the Earth. Now, Earth has had billions of years to come to equilibrium with the Sun. It is full of residual heat from formation and heat from radioactivity and heat from several billion humans running air conditioners and cars and whatnot. What is the average temperature of the Earth's surface? Clearly, it's pretty suitable for us, isn't it?

with all the heat being produced by the electronics and hardware

First you were claiming the electronics shouldn't produce that much heat. But you seem to accept that now. OK, we can move on...

as well as the Astronauts themselves, radiative forcing cannot possibly explain how livable temperature was maintained.

Why not? Radiation is how the Earth rejects heat to space, and as mentioned above, works quite well for maintaining a livable environment.

It is that simple.

No, not really. Not until you can show your work. In any case, I will try to find the numbers for you, and you can prove your case. Fair enough?

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