Works for me. The only point I think arose from that was the notion that rocks and spacecraft have different thermal properties in space because they are different materials with different ways of responding to solar illumination. Therefore you can't necessarily say that because a rock in direct sunlight in space reaches 200 degrees, a spacecraft must therefore also reach the same temperature. Thermodynamics doesn't work that way.

No doubt some will do that. It's scholarly courtesy to document your case. Equally important as documentation is demonstrating that you understand enough about thermodynamics to deal correctly with your information. There are a number of excellent online resources to help you, and a number of textbooks at your disposal. You might even consult those of us here who understand thermodynamics and can provide professional expertise.

Quite true, nevertheless an empirical measurement is impractical, therefore we'll all have to settle for an analytical approximation. It's perfectly okay to estimate numerical values you can't look up or measure. You just have to clearly label those values as estimates and perhaps explain a bit how you arrived at it. It may not be accurate, but it's honest.

"The command module uses only about 2000 watts of electricity, similar to the amount required by an oven in an electric range."

From: http://www.apollosaturn.com/facts_figs.htm

The source was trying to reflect how little energy the command module uses, but if it's enough to cook a turkey, significant cooling is going to be required in a space as confined as the CM.

From: http://lsda.jsc.nasa.gov/books/apollo/S6CH5.htm

Note that these figures are similar to the values given for power usage in the CM (which would all get turned into heat eventually).

Other research strategies that I intuitivly believe will yield available data desired include finding, if available, the ambient tempreture of other derilict spacecraft. That data is applicable to Apollo 13 because 13 was for ambient tempreture balance resembalant to a derilict. Probably be a good method and one I will try. No big complex of research there or formuli , just a question of whether the data is available.

The afore mentioned strategy of BTU capacity is another.

Research into the data acquired by the Mercury and Gemini programs, which was used to base the design of the Apollo, would probably work but would be more complex and in my intuitive opinion less available.

Guesstimates of Apollo spacecraft albedo are in my intuitive opinion the only numbers available for an albedo based strategy. Because no engineer is going to base spacecraft design on attempting to measure the albedo of a complex structure like the Apollo spacecraft when accurate experimental data from mercury and Gemini is available. So a strategy reliant on measurements of the spacecraft albedo is In my intuitive opinion not going to yield accurate results because I think the measurements were not made.

I know that some inaccurate albedo guesstimates were made prior and applied to the design of the Mercury spacecraft. But from my information that strategy was discarded when hard data came from the Mercury flights.

SAMU

Yes, depressingly common. The major conspiracy theorists bank on knowing only slightly more about a subject than their intended audience, but being able to convey the impression that they understand as much as, or more than, practitioners of the applicable field. So while Ralph Rene, for example, demonstrates he knows next to nothing about cislunar radiation or radiation in general, he attempts to establish that he's not only an expert, but more of an expert than those who make their living building machines designed to operate in cislunar space.

People who read these books then make the rounds of online forums spouting the ignorant crap they've read. Sooner or later someone presents hard data which directly contradicts the conspiracist's findings. But the reader doesn't necessarily have the expertise to recognize that it's true, just as he didn't recognize that the stuff he read in the conspiracy theorist's book was crap. It sounded plausible, so he took it as the truth and parrots it as necessary.

Faced with the inability to intelligently defend the conspiracy theory and the inability to dispute bona fide expertise to the contrary, the reader is left with various unappealing face-saving options.

Not necessarily. It's not unreasonable to want to see the calculations if they exist. As we all have agreed, a tremendous amount of information is available online and in print about the details of the Apollo program. More are being made available every day. Examples of the actual machines are available in museums. It may take quite a bit of effort, but it's not unreasonable to ask.

The question is what happens if one's desire for information cannot be adequately met. What do we conclude in the absense of verificatory information?

Looking at the larger picture, here's what has to happen. If someone like SAMU comes along and asserts that it's impossible for the scenario described for Apollo 13 to have occurred, it should be accompanied with research and documentation at that time, not after days of wrangling.

The problem is that people pop up with "food for thought", but the implication is, "This is what everyone should believe unless proved otherwise." So we all scramble to provide a rigorous rebuttal to a proposition which is nothing more than idle or uninformed speculation.

Conspiracy theorists continue to avoid accountability because we continue to play the game according to the rules they've drawn up. Nowhere else in the field of investigation is someone allowed to say, "This proposal of mine holds unless you can prove it's false."

The same problem applies here as in the radiation example above. In practice, computing radiation dosages and probable effect on the human organism is fiendishly difficult. The conspiracy theorists adopt a sort of "Star Trek" approach that all radiation is simply a simple quantity that is measured with a guage, and when the guage reaches the red line, you're dead.

The layman's concept of heat can often be simplistic. But in quantitative terms heat transfer and thermodynamics are ugly and require hairy differential equations to get right. If you want to say, under a certain set of circumstances, that the command module should have been at X degrees, then typically a page or so of computations is required. "Food for thought" is insufficient, because here's how my thought goes: the command module was built by expert professional engineers. The charge of conspiracy is being made by someone whose qualifications I don't know, and who has given no detailed case. Therefore I summarily reject the conclusion until it's supported commensurately with what I know about the command module and its designers. I know they did their homework, and someone challenging their results ought to provide an equivalent amount of homework.

Some CM equipment was mounted on cold rails but some was not because its steady-state operation without them wasn't expected to exceed its operational limits or inappropriately warm the cabin. This steady state included helping to warm the cabin to a comfortable temperature.

Simply determining the internal cabin temperature of the CM without the electronic equipment and without the astronauts, due solely to solar heating, at steady state is quite a chore. Just because portions of the spacecraft skin reach a high temperature doesn't mean the inside will.

The russians accidentally lost contact with their Salyut 7 space station while it was unmanned. When a rescue team was finally able to reach it, they found it had completely shut down, no electrical systems operating at all, and no active cooling systems either. It was cold enough inside for all the station's water supply to have frozen solid. They were able to get it back up and running.

So long as it's a derelict in cislunar space. A derelict spacecraft in low earth orbit is inapplicable because such a vehicle will undergo a cycle of alternating sunlight and shadow. Apollo 13 was in full sunlight for all of its journey save for when the moon blocked the sun.

Unfortunately you will run into the same problem as you did using lunar surface material as an example -- the derelict spacecraft you choose for your baseline data may not have the same material properties as the Apollo command module.

I think you need to come to the realization that solving the steady-state heat problem for an Apollo command module is not something you can just refer to in a table or arrive at by arithmetic averages.

That's not to say reference to derelict spacecraft temperatures is irrelevant. It's just going to supply you with a direct answer, nor is it directly applicable without allowing for materials properties.

In practice engineers will use both data points. Mercury and Gemini data are valuable because they provide empirical adjustments to the analytical figures obtained in the design. But they are not directly applicable to the Apollo design because neither the Mercury nor Gemini capsule is an Apollo capsule. So the engineer must still apply analytical thermodynamics principles, including surface albedo, to the design of the spacecraft. But he may then use empirical methods derived from previous designs in order to refine his new design.

In practice a spacecraft is not a homogeneous thermal unit. Temperature gradients will persist, even using passive and active thermal control. For the lunar module the passive effects of skin materials was used to an advantage. The various portions of the descent stage were skinned differently depending on how much heat needed to be conducted to the interior portion of that segment of the stage.

Each segment of the lunar module contained equipment whose thermal requirements varied, and so the steady thermal state included different absorption and emission characteristics that varied across the struction and provided an appropriate thermal gradient. In short, not only will thermal gradients persist, they can sometimes be useful.

On the contrary, the albedo of the materials chosen for the outer skins of the various Apollo spacecraft were quite accurately measured and factored into the design.

True enough, but this does not make skin albedo irrelevant to the design of Apollo or modern spacecraft, which is how I'm reading your argument.

Empirical data from these early programs provide an understanding of how skin albedo contributes to the overall thermodynamics of the spacecraft. We simply can't compute ahead of time the intricacies of the thermal situation. But the basic thermodynamics equations provide a jumping-off point. Then empirical data provides approximations which we can use to refine basic thermodynamics into a thermal model for a spacecraft of a given basic design.

Unfortunately Mercury and Gemini missions provide only limited help because these spacecraft were intended only for low earth orbit. The sun-dark cycle repeats every ninety minutes or so, and that differs considerably from being in direct sunlight for days on end.

Skylab may also be relevant as a derelict. It was quite warm when the first crew arrived, but this was because the outer heat shield had been stripped away in the launch. Its job had been to reflect away sunlight.

So on the one hand you have Salyut 7, which froze solid, and on the other hand you have Skylab which turned into a sauna under very similar circumstances. Which is accurate? Both are, because the difference is in how the incident sunlight was handled.

Albedo alone doesn't determine this, to be sure. The Skylab heat shield was mechanically decoupled from the station hull as much as possible. That way there was little material linkage along which for heat to be conducted. Similarly the crinkled appearance of the outer LM skin was intended. By hand-crinkling the insulation layers, the manufacturer reduced the physical contact between adjacent layers, and therefore the available paths for heat conduction.

Skylab's thermal problem was solved by an aluminized Kapton "parasol" which prevented the sun from shining directly on the station skin. Salyut froze up because there was no internal heat source, but also because its passive heat rejection systems were still intact. While the outer skin of Salyut 7 may have been quite hot during the period of solar exposure, the station was designed so that head would not be transmitted through the structure to the inside.

The lunar module had a very similar design. There was an inner skin which formed the pressure vessel, and an outer skin which provided thermal and meteorite protection. The mechanical connection between these two layers was provided by "standoffs" which greatly minimized the physical contact between them, and between the outer skin and the structural elements.

My existence is validated! (Grin!)

A friend of mine gave another useful observation: if you look at a tv set, when the tv is off, the screen looks grey. But when you actually watch the tv, you see "black." Obviously, the screen cannot display any shade of darkness that is darker than the screen with no power; it's all in contrast to the bright areas on the screen.

Allow me to provide some other intuitive guidance. I am a computer programmer who also has built computers from the ground up (marrying together component devices, cards, memmory blocks, hard drives to make a functioning computer.). I also work on mainframes. Most of the space inside a computer and computer room is for cooling. Computers throw a lot of heat. I had a 486 processor cook itself (I love the smell of burnt electronics in the morning, it smells like victory) in a little under 30 minutes. A cooling fan had failed and only the power supply cooling fan was operating. Mainframes need a lot of active cooling to keep them at a relatively cool 65 degrees. The electronics in the Apollo space program were toasty enough to need a massive cooling system (both active and passive) for the spacecraft. Without that input of heat from the electronics, whatever passive cooling systems would negate the minor input of human body heat and solar radiation. Therefore, the temperature inside the capsule drops.

__________________
Valiant Dancer

Here are some stats for skylab.

http://www-pao.ksc.nasa.gov/kscpao/h...ht-summary.htm

You will find a tempreture of 125 degrees after loss of meteor shield and a temp of 75 degrees after instalation of a very large parasol to shield it from the sun.

True it's not an Apollo and true it's not trans lunar orbit. It spent a large portion of it's time every hour in the shade of the Earth's shadow. But it's a far way from the 38 degree temp mentioned by Commander Jim Lovell's essay.

More as I find it. There are lots of derilicts up there but expectedly not very easy to find documentation.

AS to the water freezing on the Soviet Station. I don't expect data to be very available but I would point out that the freezing point of water is higher in low pressure and the boiling point is lower. An example is frozen c02 which at sea level pressure has a boiling point and frezing which is the same which is why it goes from frozen solid to gas without melting to liquid first.
SAMU

PS
Oddly this page and many other related pages are dissabled right now.

http://search.spacelink.nasa.gov/r.h...emperature.htm

But all other unrelated pages I tried on that server are showing up.

Also my last messages to this board are not showing up.


Also it might intrest you to know that this topic is nearly the hottest topic on this board based on number of replies and number of page views second only to the antigravity topic. I guess some people think it is food for thought. Not that that was my intention.

<font size=-1>[ This Message was edited by: SAMU on 2001-11-09 02:47 ]</font>

But it does demonstrate the point. Without the thermal shielding and with the electronics turned on Skylab heated up to an uncomfortable degree. Had the opposite happened, as it did on Apollo 13, it would have cooled down substantially.

And I would like to point out that the Soviets maintained sea level atmosphere and pressure in their spacecraft. Ergo your contention here is meaningless.

I point out that the designers no mater how much they know about the spaceraft or calculated to get the spacecraft to work right in the hostile environment of space or even how inteligent they were.

It was the end user, the purchaser, NASA (a paramilitary organization) that clamed that the craft had an explosion and got cold.

An example of how the end user royaly F**ked up a spacecraft because of lack of understanding of the design is Apollo 1. Which was designed to have a pure oxygen cabin pressure of one third sea level. NASA, performing a test pressurized the cabin to full sea level pressure with pure oxygen. A small spark ignited cumbustibles in the cabin and murdered the astronauts Grissom, White and Chaffee. If you've never seen a rag saturated with oxygen burn, it burns like a blowtorch.

Which should tell you somthing about the intelligence of the men who volunteered for the military during Vietnam.

Although they were clever to make the covert mission cover (if that's what it was) a lunar landing abort scenario, eliminating the complexity of faking a landing which in other threads on this board is demonstrated to be difficult to pull off.

SAMU

Quote

"But it does demonstrate the point. Without the thermal shielding and with the electronics turned on Skylab heated up to an uncomfortable degree. Had the opposite happened, as it did on Apollo 13, it would have cooled down substantially."

What it demonstrates is (if you had read it carefully) That prior to the first manned mission to the ship and presumably with few electronics and no environmental system functioning with no heat shield it got to 125 degrees. And with a heat shield with absolutly minimal contact with the hull compared to any other spacecraft and all electronics and an environmental control system functioning it was still 75 degrees and they would have liked it to be cooler. Or do you think that they placed the parasol in such a way that they had to run a heater to maintain a temp of 75 degrees?

Quote
"And I would like to point out that the Soviets maintained sea level atmosphere and pressure in their spacecraft. Ergo your contention here is meaningless."

I agree with the pressure you note as what I recall of how the soviets maintained their spacecraft. But You don't say how you know what the pressure was after they stopped maintaining it and abandoned it for a period of time and had reportedly all systems shut down. My recollection is that it leaked like a sieve. Out gassing as has been pointed out carries heat away from the ship with it and if the pressure fell then the water would have evaporated at a lower tempreture and cooled the ship more due to evaporative cooling and carried more heat away with it as it leaked out. As a derilict my speculation is applicable. Your contention is meaningless.

<font size=-1>[ This Message was edited by: SAMU on 2001-11-09 06:54 ]</font>

SAMU,

Paramilitary: (adjective), of, relating to, being, or characteristic of a force formed on a military pattern especially as a potential auxiliary military force.

What's your evidence that NASA is paramilitary?

Also, comparing Skylab or ANY other LEO SPACE STATION to the Apollo 13 craft is like comparing grapefruits to cherries. They are both fruit and can be eaten, but the similarites end soon after.

You began this thread saying you had questions you'd like us to clear up for you, which we did. But you didn't want us to answer your questions, you just want to argue, against logic, research and PHYSICS that Apollo 13 was a hoax!

I take the Piper Pledge and bow out of this thread.

CJSF 8-(

__________________
Two years ago moved from my town
I was looking up past the city lights
But the city lights got in my way

See the constellation ride across the sky
No cigar, no lady on his arm
Just a guy made of dots and lines

-from "See The Constellation"
by They Might Be Giants

Does this sentence make any sense to anyone else?

1st: NASA isn't a part of the military. Granted, they do send up military hardware from time to time, but the military pays them for that.
2nd: What would you consider proof? Being there in person?

I have a feeling that they tested it like that just in case they had to pressurize the cabin to that pressure. Wouldn't you feel better knowing that the ship you're in is tested for far greater pressure than it normally would be under? I know I would.

Also, didn't NASA design everything themselves?


Watch it. My dad voluteered to serve in the military during Vietnam. Granted, he didn't go to Vietnam, but still, don't go attacking people unless you've been there. And I honestly doubt you were.

If the landings were faked, then why not have major problems like Apollo 13 had during Apollo 11 or even Apollo 8? Why not make it seem impossible to make it to the moon rather than go and then have a major accident happen?

__________________
"You can't convince a believer of anything; for their belief is not based on evidence, it's based on a deep seated need to believe." [Carl Sagan]

Don't call that jumble of words a sentence!

All of the mess after "I would point out that the designers" is just a long, parenthetical expression. And "I would point out that the designers" doesn't say anything meaningful.

Apparently the writer forgot what the original intention was. But that's OK because most people lost interest in his (or her) views a long time ago.