A: The equilibrium temperature of an object at about 1AU from the sun may be high or it may be low depending on the size, shape, reflectivity, and radiative properties of the object.

Yes, with an if. Objects are usually not isothermal (i.e., all one temperature) in any environment. So you have to be careful when you say the temperature, especially the equilibrium temperature. Yes, an object will come to equilibrium radiatively with its surroundings. It will also come into equilibrium internally (i.e., conductively). Those two conditions affect each other. At that equilibrium, a variety of temperatures can be measured throughout the object. For an object as large and compositionally complex as an Apollo spacecraft, a wide variety of temperatures can be measured. There is no closed form for determining these complex equilibria generally for all objects, hence I make a good living doing it iteratively for real-world design problems.

Size and shape matter. When you reach the complexity I describe above, geometric factors become more important in determining what temperature some specific part of some specific object reaches. Geometry affects conduction. Geometry also affects whether an object self-radiates, and how it radiates and absorbs with respect to environment radiative heat sources. The buzzword is view factor, although it also goes by various other names.

Reflectivity is salient because it's the compliment to absorption. In general, incident light is either absorbed, transmitted, or reflected. So the coefficients pertaining to those properties for some material add to 1. Opaque objects do not transmit, so transmissivity is zero. When that is the case, all the incident light is accounted for either as reflection or absorption. What we mean when we say that a surface has a reflectivity of 0.95 is that it has an absorptivity of 0.05. So if you have 100 W of light energy in thermal wavelengths incident per unit area, only 5 W of it is a candidate for conversion to heat in that material.

The bottom line is that there is no basis in physics for saying generally that objects in space all tend to become too hot for humans because of incoming light from the sun. Heat transfer reasoning must be done by the numbers; it's too counterintuitive otherwise.

B: An Apollo stack painted all black (though it would look cool) would probably have an equilibrium temperature on the hot side.

Probably, if by "painted black" you mean that its relevant-wavelength absorptivity would increase. Accordingly its emissivity would also likely increase in accordance with Kirchhoff's law. That brings up the difference between so-called black bodies and gray bodies. In the heat transfer equations, that qualitative difference translates into net quantities instead of absolute, and quantities scaled by the relevant optical coefficients. A silver CM and a black CM are both gray bodies. One is just grayer than the other.

Emission rises faster as a function of temperature than absorption, so you find in general that equilibrium temperature curves are not linear as incidence varies, but flatten instead.

C: As designed, a completely shut down Apollo stack (by that I mean CSM and LM) had an equilibrium temperature right around freezing.

Yes, if the thermal gradient caveats from the previous section are kept in mind. Neither the CSM nor the LM would be isothermal. Human metabolism does not transfer enough heat into the cabin environment to maintain a shirtsleeve environment under the regime of the spacecraft's radiation to its environment through the completely passive means of the spacecraft's structure. Solar influx likewise.

D: Fully powered up, the extra heat from the electronics and such raised the equilibrium temperature such that additional cooling was required to maintain a livable environment.

That's misleading. A livable environment (e.g., air temperature between 70-80 F) cannot be maintained in either the CM or the LM cabins under real-solar-system operating circumstances without adding heat. The electronics transferred heat directly to the cabin air volume in some cases, and indirectly in other cases by means of the coldplates and coolant loop if needed. If the total heat load from the electronics had been added to the cabin air, it would probably have made the cabin air too hot to be livable. So the ECS cooling system was designed to regulate how much heat from the electronics -- whatever the transfer path -- would transfer to cabin air.

Heat transfer in the CSM or LM is not a linear, static model. Heat can come from several sources, transfer back and forth from components, and go to several sinks. Some of that transfer is passive in the sense that it just happens and was planned for. Other transfer is intentional and controllable by means of the ECS coolant network.

"Coolant" can run heaters also in this system, such as when the CSM is on the dark side of some large body, and the in-cabin electronics are not generating much heat at the moment. Heat from the other electronics passed to the coolant can be added to the cabin air by piping post-coldplate coolant into the cabin heat exchanger. The post-coldplate coolant will, at that time, be hotter than the cabin air temperature and will transfer heat to it.

__________________
"Facts are stubborn things." --John Adams
Clavius Moon Base

My brain shall surely explode...too much knowledge!!

Thanks, Jay...I figured the smaller white sections on the fore SM area were some sort of temperature control system, just hadn't found out what.
Is it a fair guess that the white painted LEO Skylab CMs didn't need the more reflective mylar due to their 45 sun/45 shade routine while parked on the Skylab? (tho it's said the LEO sunshine side is a bit more harsh due to reflected IR/vis radiation from the Earth, true?).

Dave
(can't wait till tomorrow cuz I'm getting smarter every day)

The pdf you (Jay) linked...

Not me. Looks like Van Rijn linked it. And to be honest, I didn't follow the link until you just now brought it up. It looked like IDW was having trouble reading it, so I didn't pay much attention to that portion of the thread. Now that I've skimmed it, I see what you mean.

I would actually recommend that file highly to IDW because it has a good mixture of overview and detail. Plus it has photographs of some of the components as opposed to the engineering drawings in my references. PDF-page 5 has a slightly more detailed version of the schematic than the familiarization manual.

I'm certain about the 50-sf per-panel figure for primary ECS radiator area in the final design. Your PDF describes an older design, and says so, but does not seem to give figures for the flight design. I remember each ECS panel in the final design had a nominal heat-dissipation capacity of at least 4,000 Btu/h, but I don't remember the exact figure. I just remembe the first digit was 4.

__________________
"Facts are stubborn things." --John Adams
Clavius Moon Base

...it's said the LEO sunshine side is a bit more harsh due to reflected IR/vis radiation from the Earth, true?

True.

Passive thermal control is about absorbing the right amount of influx, if you have it. In many cases that means absorbing very little, because your overall thermal management solution may consider other sources that are more controllable, such as on-demand heaters and electronics waste heat.

Some panels of the LM, for example, were designed to absorb more than others. The ascent fuel wants to be kept at about 70 F, just like the pilots. So you arrange to absorb enough solar heat at those parts near the tanks to get you in that temperature ballpark. Similarly a powered-off CSM in lunar livery might get awfully cold in LEO waiting for its owners to finish their space-station work. So you tweak its coating to arrange for it to absorb a different amount of energy.

In general you want to reject heat passively in the overall design, because many crucial activities aboard any spacecraft generate waste heat that you can use to bring things up to par. But on some occasions you don't aggressively reject heat through optical means.

__________________
"Facts are stubborn things." --John Adams
Clavius Moon Base

Judging by your apparent understanding of EMR, I won't
punk you out' about your error. IR is long wavelengeth EMR.
Actually, the only way to be sure is by experimentation.
I think your estimate is off a bit because I dont think you realize some non visable wavelengths are reflected by the polished surfaces.
I don't know but we can assume it was fairly high. It is the shorter wavelengths and proton radiation that would not be reflected, but converted instead to heat. ALso it is important to realize that the polished surface was by no means 100% efficient reflecting ANY wavelength. Not even a highly polished mirror can do that.

This is certainly not an accusation, so don't take it that way, but I seem unable to access any NASA PDF files.
My computer is fairly new, but the Adobe reader has never been updated. Is this the reason or does anyone know?

Is that the PDF I linked to in the following post? Here:

1st Question: How was the Apollo space craft cooled ?

Yes, it does note that the area of the primary ECS radiators were increased from two radiators of 30 square feet each to two radiators of 50 square feet each for the lunar missions. It doesn't state the heat rejection for the updated system, but assuming linear scaling (which admitedly is probably an oversimplification), if the first generation radiators could reject 3700 btu/hour, than 5/3*3700 = 6167 BTU/hour.

__________________
I say there is an invisible elf in my backyard. How do you prove that I am wrong?

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

The Leif Ericson Cruiser

It's not a conspiracy on NASA's part , they're just writing newer .pdfs than your machine is rigged to handle right now. It's correctable.

You will need to update your browser's adobe plugin if you wish to open it into your browser. If not (and I generally recommend this approach), right click the link, save link target as, then open the file into adobe reader directly. You may need to fire up your adobe reader and have it updated.

If you cannot save target as, you may need to install firefox and one of the adobe .pdf download plugins. (They're not hard to find, and if you choose this route, we can help you find it if you have trouble.) I'm pretty sure you won't need to go through this step, NASA's open about downloading resources. Other sites can get pretty protective of their .pdfs though, so this can sometimes be necessary.

__________________
And you, to whom adversity has dealt the final blow
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.

I never said that I wanted to be coddled. What I really want is to be treated with the respect I deserve. In fact I want everyone here to be afforded the respect they deserve.
Apparently you think in my case that is very little, for whatever reason.
. I dont see how you envision a one on one debate as 'coddling' one of the participants, unless of course you consider a fair debate 'coddling' the opposition. You are being coddled here, not me Jay! You were the one whining about not wanting to take me on one on one.
I personally think it was as fair an offer as any man could propose.

By the way, Jay, I was taught and I believe we are all special. I am certainly no exception.
There are only a handful of people here that will percieve my meaning .

Actually, the only way to be sure is by experimentation.

Or by numerical simulation. Less sure, of course, than by experimentation, but easier to do. It was done for the LM. Today we have well-established methods for ground-testing designs at full scale for thermal properties in space. Expensive, but worth it.

But we don't need to "be sure" in order to know that your claim is wrong. That devil ain't in those details. Basic computations can get us into the right ballpark for determining whether Apollo spacecraft would heat up uncomfortably just due to solar influx. They've been done and they don't agree with your claims. Mean equilibrium temperature is going to be quite freezing. The difference between the basic computations already done and some empirical test is not going to be on the order of the dozens or hundreds of degrees necessary to support your claim.

ALso it is important to realize that the polished surface was by no means 100% efficient reflecting ANY wavelength. Not even a highly polished mirror can do that.

Straw man. It doesn't have to be 100% efficient in order to be useful and effective in achieving passive thermal control.

__________________
"Facts are stubborn things." --John Adams
Clavius Moon Base

I have an automatic update loading now.
I have a slow connection here, my town does NOT yet have high speed access, so it takes awhile.

I guess considering the backwards community where I am, I'm lucky to have dial up.

Apparently you think in my case that is very little, for whatever reason.

If you feel I have treated you with disrespect, report it to the moderators and await their judgment. If not, make no insinuations to that effect.

I dont see how you envision a one on one debate as 'coddling' one of the participants...

I've explained it several times. It limits criticism of an idea to that which can be mounted by one man, rather than to all that which is appropriate to the idea. That is not compatible with the search for truth. Further, in the context of the typical conspiracy theory debate, which places a greater onus naturally on the debunker, it does indeed skew in your favor to impose that greater onus on one man.

You were the one whining about not wanting to take me on one on one.

Hogwash. Show where I "whined."

Nor was I the only participant to object to a one-on-one debate. The moderators, in fact, ruled that such a debate would not be allowed.

I gave you my decision on that point and gave you my reasons for it, which you immediately disregarded, clinging instead to the pressupposed reason you gave in your first post to this board. Subsequently in this thread you have already attempted to saddle me with a colossal burden of proof associated with your claims, while ignoring specific questions from me. That would suggest that my reasons for avoiding the one-on-one debate were indeed well-founded. You seem to expect everyone else to do the legwork while accepting little yourself. Why did you think it would be fair to have imposed all that homework on me alone?

__________________
"Facts are stubborn things." --John Adams
Clavius Moon Base

I have an automatic update loading now.

I hope that works for you. Much of my personal documentation is in print form, however much of the documentation from NASA that is available online is in PDF format. Hence it will be rather crucial for you to get a working PDF viewer. The slow dialup connection may also work against you, since some of the available documents are many megabytes in size.

It is appropriate to ask for patience if you feel you're being asked to read documents at a faster rate than you can access them.

I concur with the download-first recommendation. I read NASA PDFs with many different versions of the Adobe PDF reader on many different computers. I have never yet had a PDF fail to load. Therefore I tend to believe your problem is not with the reader but instead with the interaction between the reader and your browser. If you can't find a PDF reader that opens these documents in any way, then I don't know what to tell you -- that will be a serious impediment to your ability to defend your claims.

__________________
"Facts are stubborn things." --John Adams
Clavius Moon Base

Jay, with all due respect a 'Delorean" automobile is highly polished stainless steel, yet if left in the summer sun it gets almost as hot as any other color.
And dont forget, that example is cooled by air passing over it.
Simple experience can sometimes be more valuable that computer models.
What I am saying and it is not a 'straw man' arguement is that the percentage of EMR reflected can be determined for each part of the spectrum and and good estimate can be determined. Before when I made estimates you claimed they were simply invalid, since I dint know all the facts.

Poor example.

The outside of that Delorean would be relatively cool to the touch (as is my Corolla left in the hot sun every day.) The inside, which is not highly polished stainless steel (nor aluminium), is what radiates most of the heat. This is why the engine compartment is relatively cool. So is the (outer) body of the car itself. So is the inside of the trunk. But not the conductive bits (the seat belt buckle) on the inside.

The enclosed space traps most of that heat that radiates against the opaque, non-reflective, "grey" parts of the car. The enclosed space is what is preventing the radiation the outside enjoys.

[Edit: Another big difference is that the area of the CSM that is window-in-sunlight is much, much smaller than on an automobile.]

If you're on dial-up, definitely download the .pdfs. The browser plug-in is squirrely at the best of times. The download method is reliable.

__________________
And you, to whom adversity has dealt the final blow
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.

Don't forget all that light going through the huge glass windows. Then there's the the fact that it's sitting in a rather warm environment in the first place, so has limited options for radiating away heat. There's the atmosphere to complicate things, and the reflectivity (or lack thereof) of the steel at different wavelengths.

If you had experience with a comparable situation, it can be helpful. But, making assumptions based on what you might think is "common sense" can lead you astray. That's when you need to actually crunch the numbers, and you can only do that with the correct data.

__________________
I say there is an invisible elf in my backyard. How do you prove that I am wrong?

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

The Leif Ericson Cruiser

IDW...are you ever going to get around to presenting the calculations you used to arrive at the conclusions you have made??

__________________
"The facts gentlemen, and nothing but the facts, for careful eyes are narrowly watching." Isaac Asimov

Jay, with all due respect a 'Delorean" automobile is highly polished stainless steel, yet if left in the summer sun it gets almost as hot as any other color.

What part of the Delorean? When you say "it" gets hot, are you referring to the air temperature inside? The surface temperature of the hood that you put your hand on? What's the temperature of, say, the oil in the transmission? Is it as hot as the surface of the hood? Why or why not?

Consider air temperature in that hot car. How did the air inside it get hot? Was it through conduction from the surfaces of the car? Or was it primarily from sun shining through the windows and being absorbed by the materials from which the dashboard, seats, and other interior structures are made? Why do you think those visors you buy for the windows work so well at controlling the inside air temperature of the car?

And dont forget, that example is cooled by air passing over it.

No. As I mentioned earlier, air is available in general for heat transfer. You can't assume it has only a cooling effect in your example.

Simple experience can sometimes be more valuable that computer models.

Only when it's correct. When you say a Delorean on Earth gets hot therefore a spaceship in space should get hot, you have the burden to prove that a Delorean on Earth is equivalent in all material thermal respects to a spacecraft in space. You haven't done that here. You're begging the question that it's valid comparison. If your simplification simplifies away important differences, it isn't more valuable. You have the responsibility to ensure you don't do that.

My computer models are used to validate designs whose development budgets are in the billions of dollars. Those people have a lot at stake and choose only what they know works. Computer models are used because they work. Don't dismiss them lightly.

What I am saying and it is not a 'straw man' arguement is that the percentage of EMR reflected can be determined for each part of the spectrum and and good estimate can be determined.

I agree it can. What I objected to as a straw man was the insinuation that only 100% reflectivity would be useful in passive thermal control. Since much of this discussion seems to depend on understanding passive thermal control, it is important for us to be on the same conceptual page.

__________________
"Facts are stubborn things." --John Adams
Clavius Moon Base

Good point. I forgot the atmosphere helping things along. In a local deep winter, in balmy -30C weather (balmy compared to LEO, anyway), my car, sitting in direct noontime sunlight will still be about -25C (guesstimate, but by feel, it's probably a good one) on the inside.

It certainly takes a while for the inside to warm up once the car is started.

[Edit: I'm calling it a night. The lightning storm is getting close and the lights have been flickering a bit. I think we're close to a power failure.]

__________________
And you, to whom adversity has dealt the final blow
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.

I had a Delorean back in 1989 that I bought as an investment, and as I recall it and every other car in Texas left in the midday summer sun was too hot to sit on. The point of course that metal objects left in intense sunlight heat up nomatter how polished they are. Again, this is only personal experience and hardly 'evidence' of anything, except of course to myself!

Aluminum being the great conductor of heat it is tends to register lower temperatures under the same conditions than stainless of course because it conducts the heat away from the sunlit area to cooler areas to be radiated., but aluminum objects heat up too.
Try it.
It's an easy experiment to do to prove it to yourself.


Conditions in space are harsher.

It should also be pointed out that a great deal of experimentation *was* done in the form of orbital, translunar, and deep-space probes long before Apollo 8 ever left Earth orbit, not to mention all the development and characterization work done by the materials scientists on the different materials and coatings.

I am not really sure where this thread is right now. It has been well established that an object in space will not automatically heat up to an unsustainable (for life) temperature, and that includes a generic manned spacecraft. It is also clear that the details matter in calculating what sort of temperatures will characterize the various equilibrium states. If IDW does not have those numbers in order to calculate this for himself, and he cannot read the PDF files or have access to paper versions, then any further discussion is pointless. Unless we supply him numbers for the spacecraft basic geometry, materials used, alpha and epsilon numbers, coooling loop numbers, evaporator capacity, etc. I personally do not mind doing so, but it will take some time.

__________________
"Slapping a guy on the head is just as funny now as it was eighty years ago."

If you dont want to lose your electronics the best thing to do is disconnect them.
I had one computer fried by a lightning strike through the telephone line 2 years ago, and another I suspect suffered a similar fate.

Please define "harsher" in this context. Conditions in space are different. You can't just say "my car gets hot so an arbitrary spacecraft in an arbitrary location will get hot." It doesn't work that way.

__________________
I say there is an invisible elf in my backyard. How do you prove that I am wrong?

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

The Leif Ericson Cruiser

I think it would be more accurate to say, conditions in space are different.

__________________
Hwæt! We Gardena in geardagum,
þeodcyninga, þrym gefrunon,
hu ða æþelingas ellen fremedon.

*Shakes fist at Van Rijn

That'll serve me for not updating first.

Also, sorry about attributing the pdf link to the wrong person earlier. I had initially left it unattributed but went back to change that in order to help identify which pdf I was talking about and totally flubbed it. Rookie mistake.

__________________
Hwæt! We Gardena in geardagum,
þeodcyninga, þrym gefrunon,
hu ða æþelingas ellen fremedon.

EM radiation on earth is not EM radiation in space. There's no point in comparing them.

__________________
I was just sitting here contemplating the immortal words of Socrates who said, "I drank what?"

"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"

The exterior of the CM was aluminized Mylar. The DeLorean was brushed stainless steel, not reflective shiny Mylar. Now, I'm not certain what the Mylar coating does to heat absorbtion, aside from reflecting a great majority of the visible spectrum, but comparing CM to car may be a stretch.
Now, put the car in a .35 deg/sec roll, in a vaccuum, where the shaded portion radiates heat away and becomes cold. The PTC roll had a function, as did the Mylar, radiators and sublimators.
Hoping you can get Van Rijn's .pdf downloaded, it's a great report on the ECS.

Interdimensional Warrior:

CT loving Mod IS on the board

Mod ruling - NO 1v1 debate - If Jay chooses (or not) to engage in such, it shall be in personal correspondance. This is a community board. The community posts. RULING. If this is unacceptable to you, perhaps a BB is not your cup of tea.

Mod ruling - 'whining' - no evidence, ruled Ad-hom. Please take the time to familiarize yourself with our rules. Foremost, ad-homs are not allowed. Please take this as a warning.

__________________
"I have this theory that the Apollo missions were faked when NASA found out that general relativity was wrong because the Earth was expanding due to the Sun's iron core being influenced by magnetic waves from the electric universe after being perturbed by Planet X and thereby causing global warming. Where should I start a thread about this?" ~ ToSeek

"Those are the people that wonder how a thermos knows whether to keep something hot or keep something cold." ~ NeoWatcher

The Space Shuttle, the International Space Station and the Russian Space Station MIR all use or used this technology. So I don't see the mystery as to why Apollo couldn't be cooled.

Here's a link to the LM thermal control system.

http://ntrs.nasa.gov/archive/nasa/ca...1972013195.pdf

BTW, I can verify that the lead author is a real person.

Here's a link to thermal testing of the APollo systems.

http://ntrs.nasa.gov/archive/nasa/ca...1974012430.pdf

and another,

http://ntrs.nasa.gov/archive/nasa/ca...1976019157.pdf

You know, something I don't see here is IDW engaging in any form of debate. He's just bringing up different assertions without acknowledging any of the relevant posts with answers.

__________________
I was just sitting here contemplating the immortal words of Socrates who said, "I drank what?"

"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"