Glad I could startle you! [img]/phpBB/images/smiles/icon_biggrin.gif[/img]

Actually, I said nearly as bright. There are two factors that would cut that down: less-than-perfect reflectivity (SAMU is not claiming that the moon is pure white), and the fact that the moon is a sphere, so only a fraction of the incident light would happen to head our way. That's why I suggested a "dark blue sky" if the moon were more reflective than it is.

If the moon were, in fact, a plane (or slightly parabolic) mirror aimed just right, we'd see an image of the solar disc, almost exactly the same size as the sun; a full moon would produce 24-hour daylight. And daytime heat, too, if the mirror was good down to IR wavelengths.

Weren't the Russians toying with the idea of orbiting large mirrors to bring more "sunlight" to Siberia and increase crop yields? Anybody remember this, and know what came of it?

You wouldn't happen to have the numbers for the Titanium alloy used in the CM and/or LM, would you? (Of course, even this isn't definitive unless you know something about how the outer skin was thermally coupled to the cabin.)

How about white paint?

Open letter to all who respond to SAMU -

[quote]
<font color="blue">On 2001-11-03 03:46, SAMU wrote:
I hope you can answer this question</font>

SAMU's subsequent actions indicate that he doesn't really want answers. He wants confirmation for his wild, off-the-wall imaginings.

<font color="blue"> and if not I hope it gives you food for thought</font>

Oh, it has. But I doubt that you would be pleased with my thoughts.

<font color="blue">If you ask some questions sensitive to this scenario of your contacts in NASA and they suddenly freeze up,</font>(emphasis added)<font color="blue"> could you let me know that?

Yours
David Samuel
70116 </font>
</quote>

In short, he seemingly wants to hear back only if the response confirms his idea but not if it doesn't.

One more time. Aluminum reflects anywhere from 85% to 91%(depending upon surface treatment such as anodizing, roughening, etc.) of the light that falls on it. Solar energy at earth orbit is 0.033 cal/sec/cm^2. This means that about 0.0043 cal/sec/cm^2, as an assumed overall average, actually enters the aluminum. If the aluminum radiates as a black body the temperature of the skin would be about -36 deg C, or about -32 deg F. The astronauts would rapidly freeze to death.

And, by the way, that heat input is only for those square cms. that are at right angles to the suns rays. Most parts of the capsule exterior would be at some grazing angle less than 90 deg and the heat input to those parts would go way down.

The aluminum of the capsule doesn't radiate as a black body since aluminum has a relatively low emissivity. I've forgotten how to handle that in heat computations (it's been a looong time) but from previous posts and NASA information, the inside temperature was in the vicinity of 4 deg C, or 40 deg F. which is in accord with a low emissivity because the object has to get hotter to get rid of the heat input and get to equilibrium.

SAMU spoke of one side of the capsule at 200 deg F. and the other at -200 deg. F in a previous post. Anyone who thinks that an aluminum structure would support such a large temperature gradient in such a short distance is obviously not very aware of heat conduction and his opinions on heat and temperature in general can be safely disregarded.

This is the end as far as I am concerned. I'm not even sure why I'm bothering with this since, as someone posted, SAMU obviously has a speculation and loves it in spite of anything said.

So let him. The sun will still rise tomorrow and NASA will go on with its work, entirely undisturbed by such bilge.



<font size=-1>[ This Message was edited by: David Simmons on 2001-11-05 10:19 ]</font>

I have pictures of asphalt I took that make it look bright white. How things look depends on many things, not the least of which is how you expose the film. There are pictures of the Moon's surface making it look pitch black, too. Worse, the illumination of the lunar surface depends on the angle of the sunlight with respect to the camera as well.

As I said before, this is a complicated topic with many "side issues" which are critical to understanding them. I strongly urge you to do what I did: research this issue first. I have made plenty of mistakes while discussing this issue, but I followed up by researched them, and wound up learning quite a bit. Far from casting any doubt, my research has reinforced the idea that these missions were indeed real and an incredible achievement.

As far as your weblinks go, you seem to be terribly confused. The thermal capabilities of the Apollo capsules were designed with two things in mind: the electornics run hot, and that heat must be dumped. So, if the electronics are off, the capsule will perforce be cold. It's really just that simple.

Could you post some of those, Phil?

CJSF

Okay, engineer checking in.

First, albedo. Geometric albedo concerns only zero-phase diffuse reflection. It does not consider specular reflections, which in many substances accounts for a vastly different visual phenomenon. The moon's albedo is measured as low as 0.07 and as high as 0.12, meaning it diffusely reflects between 7% and 12% of the light it receives back toward the source of the light. The earth's albedo is somewhere in the 0.30 range, considerably brighter than the moon. In fact, when you see pictures of both the earth and the moon taken by outbound interplanetary spacecraft, you have to artificially brighten the moon because the correct exposure for the earth leaves the moon a rather unimpressive dark brown.

The moon appears bright from earth because it's a the brightest object in an otherwise lightless environment. Look at a candle in daylight, then look at one in an otherwise dark room.

Second, asphalt. Or more properly, "bitumin asphalt concrete". "Concrete" is, in the general engineering sense, anything composed of an aggregate and a cement. In what we commonly call concrete, the aggregate is sand and gravel and the cement is Portland cement or other such compound. "Asphalt" (bitumin) is the cement in the asphalt concrete used in roadway construction. The aggregate is usually pea gravel. The bitumin asphalt holds the aggregate together in the same way Portland cement holds the aggregate together in concrete.

A freshly laid asphalt concrete roadway has a geometric albedo of about 0.04, or almost half that of the moon's lowest measurement. After about five years, the bitumin asphalt wears off the top surface of the aggregate and the geometric albedo rises to about 0.12, or equivalent to the highest estimate of the lunar albedo.

Thus it is not correct to compare the albedo of the moon to a freshly laid asphalt roadway. It is more correct to compare it to an asphalt roadway after several years of use, the ones that appear almost white. In fact, the geometric albedo of worn asphalt concrete is not especially less than the geometric albedo of ceramic concrete.

The thermal behavior of an object in space under solar radiation is directly affected most strongly by the reflectivity of that object. The Apollo command module was covered in aluminized Kapton insulation. The lunar module was covered in several blankets of aluminized Mylar insulation. The geometric albedo of these materials as applied to the spacecraft is in the 0.50 neighborhood. (It differs from the values for aluminum because the Kapton and Mylar sides were outboard.)

Some portions of the lunar module descent stage were covered in absorptive material because the machinery behind them actually needed to absorb a certain amount of solar heat in order to maintain the correct operating temperature.

It's clear SAMU doesn't have the appropriate expertise in thermodynamics or heat transfer to evaluate the viability of his theory, or understand the objections to it. The "Apollo 13 as a publicity stunt" theory is popular among hoax believers. Unfortunately it fails for two reasons. First, the popularity of Apollo missions hit its nadir around Apollo 15 or Apollo 16, and no "stunt" was forthcoming to fix that. Second, the failure of Apollo 13 is cited as a direct contributor to the decision to terminate the project. Its overall effect was to shorten the project, not perpetuate it.

I'm always impressed by the HBers, Cassini protesters, etc., who seem to think they know more about the space environment and spacecraft design than the people who have spent their careers sending hardware into space. [img]/phpBB/images/smiles/icon_wink.gif[/img]

Jay Utah-- impressive display of knowledge. I must admit that my own knowledge of asphalt is limited. It is interesting to know that asphalt's albedo changes. Perhaps a more appropriate comparison to the Moon's albedo is a blackboard, and not asphalt. I'll keep that in mind.

The Moon is not a specular reflector; properties in the soil make it tend to reflect light back in the direction from which it came. I plan on extensively adding to the Moon hoax page eventually, but I can hardly keep up with everything else right now. [img]/phpBB/images/smiles/icon_wink.gif[/img]

Again, I am impressed with the level of knowledge of many of the readers of this board.

Well!!!


OK, the Moon is black as asphalt. Fine, according to some philisophical hokum white is black. Go ahead and believe it you true believers. THAT, I'm not buying.

You want to talk metals? Now you're talking my bussiness. I've got 2500 pounds of my own aluminum handiwork in deap space right now. With a little heart and arrow with me and my girlfriend's initials scribed inside one big piece. You see those C-17 Airforce transports dropping food to the Afganies? I cut the titanium jet tailcones for most of them. You fly Boing 747, 777 etc. Your life is swinging on my handiwork bigtime. Ever bring your kids to the aquarium? Guess who's hand made that 20 ton piece of plastic thats holding back those 20,000 tons of water from crushing your kids to a screaming pulp. That's me.

I make assertions and have the courtesy, not to mention the scientific propriety, to provide links to official NASA drawings, images and figures to support my assertions.

YOU make assertions and expect ME to do the research to support YOUR assertions.

Tsk, tsk, tsk.

You sound like creationists.

I don't think it's too much to ask that if you say the moon is as black as asphalt or a blackboard that you find some pictures from the NASA image gallery, to which I provide a link, containing hundreds of pictures of the Moon from every concievable perspective that you find some that show it to be black. Instead of playing some occult philisophical numbers game.

Not that any of that makes a bit of difference to the point that there is no legitimatly supported theory as to why Apollo 13 got cold when enormous expense is invested in throwing a cooling system that is designed to manage deadly heat up there and it "has to be turned off".

Heck, calling it a cooling system is to under rate it to the point of idiocy. Once the launch stages fall away the spacecraft themselves are nearly all life support system. And life support means pressure vessel, air and cooling.

SAMU



PS

That aquarium plastic mentioned above, It's DOT designation is PVHO. Presurized Vehicle Human Occupancy. And none of it meets the DOT Specs. Just thought you'd like to know.

<font size=-1>[ This Message was edited by: SAMU on 2001-11-06 00:58 ]</font>

People, People, People . . .

I am sorry but I have to step in here. It is true that I was going to step in and defend "The Cause" but in light [img]/phpBB/images/smiles/icon_lol.gif[/img] of what is happening I must state simply.

Please stop confusing SAMU with facts.

I can't believe I said that with a straight face. [img]/phpBB/images/smiles/icon_smile.gif[/img]

I regards to the security oath. Now I personally have never had a reason to see or sign a security oath. But I believe that they might exist. But that just the idea of them dumbfounds me. Follow me here:

If I were were a spy. And the company says "Sign this document stating that you will not reveal secrets to anybody and if you do tell somebody we'll prosecute you." I would sign that document in a heartbeat. That way I know they wouldn't suspect me if the information ever got out because I signed it so it must be true.

OK so I got that idea from an old M.A.S.H episode . . . sue me [img]/phpBB/images/smiles/icon_smile.gif[/img]


Hauteden

I actually do love the banter I learn so much
please don't stop.


<font size=-1>[ This Message was edited by: Hauteden on 2001-11-06 00:25 ]</font>

Let me guess, it's the one with Col. Flagg and Sydney the shrink? IMO, Flagg is his own comedic<sp?> relief. [img]/phpBB/images/smiles/icon_biggrin.gif[/img]

__________________
"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]

SAMU

Just out of interest, do you discount the possibility that Apollo 13 was exactly what NASA said it was?

Buy a torch. Find some asphalt. Shine said torch onto said asphalt in the night. Observe appearance of aforementioned asphalt.
Realize that, in fact, you are wrong.
Now take a small, black, rocky planet sized body. Shine a star at it from 150,000,000km away. Observe said rocky planet from 300,000km away.
Compare aforementioned illuminated rocky planet with aforementioned illuminated asphalt.
Realize that, in fact, you are wrong.
_________________
"We want a few mad people now. See where the sane ones have landed us!" - George Bernard Shaw

<font size=-1>[ This Message was edited by: Hat Monster on 2001-11-06 10:12 ]</font>

You're the only one saying that, at this point. It is NOT black. It is as DARK as asphalt with an albedo of about .12 at it's brightest.

The biggest reason why the moon looks "white" at night is because your EYES and BRAIN adjust the contrast of the image on your retinas. Hence, one of the BRIGHTEST objects in the sky at night - the MOON - appears as the BRIGHTEST object to your eyes... the contrast is changed and it appears white.

For proof your brain did this, look at the moon from inside your house with ALL the lights off. Then, after a few minutes, TURN ON THE LIGHTS. GUESS WHAT? Your retinas get overloaded for two reasons.

ONE, your irises are wide open and can't close up fast enough to compensate, and

TWO, your brain has wired the contrast of the images so that the MOON is near 100%, so the light is WAY too bright for your brain to process.


I use a computer everyday, but I don't claim to know precisely how the video card communicates with the CPU. So you work with metals? Big deal! You don't have to cut metal to understand the physical properties of it.

We ARE doing the research (or have done it) and are presenting the RESULTS to you. You choose not to accept those results. That's your perogitive.

Tsk, tsk, tsk.

ummm...

The photographs of the Moon don't show it to be DARK (NOT black) because in order for it to show up, the CONTRAST HAS BEEN INCREASED TO MAKE IT VISIBLE. The lenses and film speed and exposures used were chosen to make the Moon appear at least as it does to our eyes at night (and in some cases brighter or with MORE contrast). It doesn't help anyone to visually analyse the Moon's surface if they can't see it.

Now - for some images that DO show the Moon as dark! NOW you're talking!

http://home.earthlink.net/~dancingdinos/index.html

http://antwrp.gsfc.nasa.gov/apod/ap980129.html
NOTE: The above image's captions states that the Moon's brightess was increased FIVE times for the image.

There have been thorough studies of the Moon's albedo, and they all indicate something between .06 and .12 (or 6-12%). Would you like us to dig up some reference for you to personally look up? I'll try and do so, if you want.

Apparently you haven't read any of the responses to your questions or you really don't care and are just stirring up trouble.

right................

CJSF

_________________
"Be very, very careful what you put into that head, because you will never,
ever get it out."
--Thomas Cardinal Wolsey (1471-1530)


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

That's the nature of engineering. You spend your whole life studying stuff that no one in his right mind would be interested in, and then in one shining moment it all pays off when that obscure bit of knowledge suddenly becomes useful for something.

I think everyone's seen the difference between freshly laid asphalt, which is a deep black, and asphalt that's been around for several years. Obviously the color changes. The change in albedo isn't all that apparent to the naked eye, but can be inferred. We know that the color brightens, and that bright colors have a higher albedo than dark colors.

Not only do you get the effect from car tires which rub the bitumin film off the top layer of aggregate, but you get dust and grit ground into the upper layer of bitumin between the aggregate, the same way dirt works its way into the calk around your bathroom fixtures.

Perhaps, but I don't know the albedo of a blackboard. Asphalt is appropriate, so long as you clarify that it's weathered asphalt and not the freshly laid variety.

I live in Utah where we have a great deal of sun and lots of asphalt roadways. Which brings me to your comment...

True, but asphalt is. I wasn't trying to describe the moon as much as I was trying to point out that geometric albedo is a poor quantification of the total lighting properties of a surface. Something like asphalt with a "low" albedo can actually reflect enough light in the specular sense (not measured by albedo) to impair vision. The glare off the asphalt roadways here in Utah is quite striking.

You mention the moon's emphasis on zero-phase lighting. That's correct, visually verifiable from earth, and quite evident in the Apollo lunar surface photographs. Again, geometric albedo does not account for these "special" lighting effects, hence it is a poor quantification for the lighting properties of the lunar surface.

No, that's the antithesis of my point. The moon is not black. It's equivalent to a weathered gray asphalt roadway, not a freshly laid black asphalt roadway.

The skill of cutting metal to a pattern given to you by someone else is not equivalent to the skill of determining those patterns. That happens to be my busines. When you cut tailcones or wing spars or what have you, you're simply following the instructions given to you by people like me who work out the designs for you.

The arguments you offer in favor of your assertions demonstrate that you don't understand thermodynamics. A proper understanding of thermodynamics is necessary to the claims you're making. Not only do you seem rather ignorant on the subject of thermodynamics, you seem especially antagonistic to those who are trying to educate you.

I can only speak for myself, but I'm claiming the moon is as white as asphalt, the kind that's been around for several years.

What do you mean by "legitimately supported"? The thermodynamics numbers others have posted seem correct to me. The only quantitative arguments you have made don't constitute valid thermodynamics.

The cooling of the command module has been explained to you as plainly as it can be. The primary source of heat on the Apollo spacecraft was the electronic equipment. The heat production of the astronauts and that absorbed from the sun is very small in comparison. If you run the electronic equipment you must also run the cooling units. If you turn off the electronic equipment you do not need the cooling units. You must either run both or neither.

Without that electronic equipment, the only sources of heat are the astronauts themselves and the radiant heat absorbed from the sun. You've been shown the black-body figures for an object in that situation, which you have sidestepped.
Machinists often have intuitive knowledge of a material's properties because to cut it efficiently, correctly, and without damage one must adjust "feed" and "speed" values on the machine and arrange for the appropriate coolant during machining.

But these are typically given in tables. A good machinist can set the feed/speed values for various aluminum alloys and such from experience. But that's not the same level of experience as the person who originally specified that material for use in the project under construction.

A machinist knows not to let the material get too hot. But he doesn't necessarily have to know how or why it gets hot, or compute transfers and steady states for the thermal situation. And he doesn't necessarily have to know why he's cutting it 0.256 inch thick instead of 0.248 inch. And he doesn't know why that particular alloy was chosen for that particular component. That's the job of the design engineer upstairs.

Needless to say one doesn't become a design engineer without understanding the general problem of thermal effects -- what causes them, how to quantify them, and how to make them work to his advantage.

Chris,
Thanks for the post of these pictures. This leads me to a question. How difficult would it be for an astronomer on Mars using a 10" reflector to actually observe the Moon? I'd think with its dark albedo, the Moon would be hard to observe. Any opinions?

Jay,

Well, I have come across one bit of albedo stuff online that talks about how difficult it is to compare albedos on Earth with that of objects in space.

http://www.roboticobservatory.com/je...ech/albedo.htm

I will note that comparing the albedo of grass to that of lunar surface material as this author does, is not a "fair" comparison either. Grass looks green to us mostly because chlorophyll absorbs most of the red and blue wavelengths it receives. The brightness of grass is also due to our eyes/brains manipulating the contrast. The problem there is that one can measure albedo in various wavelengths.

Here is a report from an instrument called GOME:

http://www.sron.nl/divisions/eos/gome_moon.html

It shows the albedo falling withing the 6-12% zone, on average, with what seems to be a slight, linear increase in albedo from Near UV to Near IR wavelengths.

CJSF

__________________
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

Christopher, excellent material!

I especially like Medkeff's straightforward and comprehensive examination of the geometry of the lunar regolith and its effect on light. Not only does this dispel the incorrect use of albedo as a practical measure of lighting properties, it gives the beginner something of a foothold on what is otherwise an obscure bit of science.

It's difficult to convey in purely textual form the geometrical nature of the behavior of reflecting light. A few years ago I came across a visual representation scheme for incident and reflected light used by computer graphics people, namely Cook, Torrance, and Sparrow. It represents the intensity of reflected light in any direction by a vector along that direction whose magnitude is proportional to the reflection intensity. The set of all such vectors form a surface composed of the vector heads, and which conveys for some incident light direction the total character of the reflected light.

The study of the illumination properties of the lunar surface applies to conspiracy theorists such as David Percy who maintain that the down-sun surfaces of objects should be totally black. The occlusion of shadows by their casting objects at zero phase angle, coupled with the zero-phase reflection through spherical soil particles answers quite effectively the notion that only objects directly illuminated by sunlight on the lunar surface will receive light.

re "light and dark," think about sunspots. They look "dark," even though they're incandescent and bright. It's counter-intuitive: sunspots "look dark." They are obviously "dark spots." Except...they aren't. Not only are your eyes untrustworthy to measure this sort of thing, so are cameras.

Silas

Ah, excellent analogy. I'll have to remember that.

I read the essays on albedo and I'll have to think carefully about this. I know that albedo is a difficult topic (it makes assumptions abotu reflection spectra that may not be accurate) so I want to make sure that I don't say something that makes matters worse.

SAMU, comparing me to creationists is pretty funny, and terribly ironic. I admit when I am wrong, and try to find more info. Several people here (including me) have shown you exactly (and politely, mind you) where you are not correct, but I have not seen you even attempt to assimilate this info. You just deny it.

SAMU, first I was going to congratulate you for not being completely uninformed on some technical matters. For instance, you know the difference in the different types of heating (convection vs conduction vs radiation), something many hoax proponents don't understand.

However, you are not as informed as you think you are. It has been pointed out there are many small details that affect conditions and you ignore them or just refuse to accept them. How can we convince you if you refuse to listen?

The spacecraft temperature issue has been explained to you. Yes, there are radiators on the Service module. Yes, there are three components to the heat load - the human metabolic heat, the solar radiation accumulation, and the heat from the electronics. It's the specifics that give you pause. Solar radiation accumulation can be mitigated. Pick the material properties, and the surface properties that give you what you want. They used white paint and white thermal blankets specifically to reflect as much incoming radiation as possible, and to emit as much as possible. This is understood by engineers. In fact, we build tools and equipment for the Shuttle and Station using the same principles. Some are painted white, but a lot are anodized aluminum because paint gets chipped off too easily in some applications. There are lots of guidelines to design tools and equipment to keep them from heating up in the sun. Apollo used similar controls for the exterior of the Command and Service Modules.

It has been stated that the electronics generated heat, and that with the electronics off, they were not generating heat. Thus the vessel would automatically be cooler than nominal case. How much cooler is a function of how much heat the electronics puts out running and how efficient at rejecting solar heat buildup the ship is. Since the design was to be as efficient as possible in rejecting solar heat, and the electronics put out a lot of heat, the difference was significant.

Rolling the ship to keep thermal equilibrium would not change the situation. If they pointed one side only to the sun and let the other get cold, the interior temperature would not increase, because you still have the same amount of solar incidence and emissivity. However, you would get a thermal gradient across components and systems. Perhaps enough to rupture the pressure skin, or perhaps enough to freeze out electronics in the Service Module required on reentry systems, or perhaps enough to rupture fuel lines. Etc. Thermal gradients bad. And it would not have helped the crew stay any warmer.

What about the long underwear? Those were designed as a cooling garment. They are lined with plastic tubes filled with water that pumps through and removes body heat. Off hand it seems logical to think that if they just didn't pump the water it should work as normal long underwear, but the water would still be in the tubes, and still act as a heat sink from the body. Parts of the tubes are exposed to the air, so it would still remove body heat. While it would be slower than an active pumping of the water, it would probably be faster than not wearing the suits.

You mention the heat removal systems - the radiator panels and cooling systems. Well, those were all turned off, too. You think that would make the vehicle stay warmer. Yes, but warmer than what? Warmer than running the cooling systems and not running the rest of the electronics? Just because the active cooling systems are off doesn't mean the lack of heat generation isn't enough to make the overall situation cold.

Example: my apartment. Right about now the temps are mid 80s in day, and dropping to 40s at night. During the day, the apartment gets warm unless I run the A/C. However, at night I can turn off the A/C when I go to be and I still wake up to a cold apartment in the morning. I'm not running the active cooling system, but the heat generation inside the apartment is not enough to compensate for the heat loss to the environment. Same thing with the Apollo. The active cooling systems were off, but the heat generation devices were off, too.

So your expectation of the situation is not correct, but you use that expectation to reach the following possible conclusions:
I note that you have already concluded that it was a hoax. You do not even allow the possibility that everything was just as NASA said and you are just uninformed. That certainly makes you seem less than open minded. Will you not at least concede it's possible you don't know all the technical details?


SAMU said:
Why is that remarkable? Again, the connection is one you are making but it is not necessarily fair. What range should it fall in? Should it automatically be cold enough to freeze? Should it remain a balmy 68 deg F? What makes the temperature range it reached suspicious to you? Did you already suspect the mission was hoaxed and look at this as something confirming your idea? How are you qualified to a priori determine that the temperature range is suspicious? This is what bugs people here. You notice a similarity (the temperature range corresponds to what could be reached using cold water immersion) but haven't supplied a justification for why that explanation is preferred (more logical) over the official story.

Again, what is suspicious? Yes, they breathed in oxygen and put out carbon dioxide. Yes, the scrubber system was not designed to handle three people for that length of time. Yes, CO₂ is related to metabolic output of heat. Please tell me how that is suspicious. If I jump to a conclusion here, it seems you are saying that they had body heat and so the cabin shouldn't have gotten cold. I don't see how you can quantify that conclusion based purely on CO2 output.

The sand and the bumper are not in the same thermal conditions as the Apollo spacecraft. And just because you have not heard of a design characteristic does not mean that nobody is aware of it. In a purely radiation heating environment, two factors are important - the albedo and the emissivity. Albedo is light reflectivity - how much of the incoming radiation is reflected away. Emissivity is how much of the internal energy is dispersed. The properties of the spacecraft were optimized for a high albedo and high emissivity. Chrome bumpers and white quartz sand are not.

You don't reference the original source. However, I think you are misunderstanding the statement. I believe the above sentence applies to the vehicle with all electronic systems active but the water cooling is off, vs. the Apollo 13 case of all electronic systems off and water cooling off. Big difference between the electronics putting out heat and not putting out heat. This appears to be a statement of how long the systems would remain operational without active cooling, not how they would behave unpowered.

NASA is not any of the above organizations. NASA is a civilian organization (not DoD) that is run in the public.

The Shuttle has in the past run classified missions for the DoD. However, that ended circa 1992.

Your argument is flawed. There are plenty of known cases of government whistle blowers, people who signed security oaths that spilled the beans because the project was dangerous. It is extremely difficult for governments to keep the existence of projects a secret. Especially after 40 years. The sheer scope of the necessary involvement is staggering, and to think that not one person with direct knowledge has come forward in all this time, or left "deathbed confessions", really speaks volumes.

Yes, but you fail to recognize one small but important detail - what is the source of the heat that the cooling system is removing? Is it solar radiation, or heat from the electronics systems? In Apollo's case, mostly the latter, which were powered down on Apollo 13.

Regarding the albedo of the moon, I, too, have always questioned the comparison to new asphault. After all, I can see the moon in the daytime sky - I did this morning. However, comparing to old asphault definitely fits better.

Regarding the moon rocks and their color:

http://www-curator.jsc.nasa.gov/curator/lunar/lunar.htm

Or from http://www.solarviews.com/eng/edu/moonio.htm
Luna is the only natural satellite of Earth and is one of the darker objects in the solar system. Its rocks are mostly dark gray and it reflects less than 15% of the sunlight that falls on it.

http://nssdc.gsfc.nasa.gov/planetary.../moonfact.html

That's a start for references.

Now you're just displaying a strident refusal to listen to anybody. The cooling system is required when all the electronic systems are powered ON. On Apollo 13, they were all powered OFF. Does it make sense to you NOW?



Donnie B. said:
This is not entirely correct, or at least the phrasing is murky enough to be misleading. The Lunar Module did use an active water cooling loop. That water circulated to remove heat from the cabin. Also, the cooling system did vent water to space to remove heat. This is through a phase change process (sublimation). However, they were independent water loops connected via a heat exchanger. Just wanting to be technically precise.

BA and JayUtah, you two mention "specular reflector" vs. the albedo. I do not understand what you mean. Could you please explain?

You're right, I was less than precise. The point I was trying to make was that you don't always have to use radiation to get rid of heat; you can dump it overboard.

Incidentally, this unusual cooling system cost some of the Apollo 13 mission controllers a lot of grey hairs. Throughout the return leg, the spacecraft continually drifted off course, an effect that was serious enough to require a burn to get back into the middle of the reentry corridor.

During the flight, no one could figure out why the course was changing. Later, they realized that it was the impulse from the LM's coolant jet.

In normal operation, its effect was negligible. But of course, since the LM was normally jettisoned before leaving lunar orbit, no one had ever considered what it would do over a 3-day period of trans-Earth coast! Once they jettisoned the LM shortly before reentry, the drift stopped.

Just thought that tidbit might be interesting.

The various definitions of albedo do not generally account for any lighting conditions other than Lambert surfaces -- those which reflect light uniformly in all directions regardless of incident light angle.

In contrast to the Lambertian surfaces we find materials which reflect greater amounts of light in a particular direction congruent to the incident light angle. We term this "specular reflection". Roadway glare is one example of it.

In practice all surfaces exhibit some degree of diffuse or Lambertian reflection, and some degree of directional or specular reflection. The common definitions of albedo use only the former, while both contribute to the actual light reflecting properties of the surface, depending on the direction of observation.

Bad Astronomer emphasized that the lunar surface is neither perfectly Lambertian nor possessed of a particularly salient specular component. The major non-Lambertian reflection component is the zero-phase reflection, or reflection along the reciprocal angle of the incident lighting angle, back to the light source, regardless of incident angle.

Various artificial materials such as Reflexite are constructed to specifically exhibit this property.

While this represents non-Lambertian reflection, it is covered by the definition of geometric albedo which specifies that the light measurement be taken from the zero-phase direction. Materials presented by Christopher demonstrate that measurements taken according to this method give albedos for lunar surface features that far exceed those of asphalt or other common comparison.

I've said all I'm going to about the color of lunar rocks and soil. No one can research answers to all questions presented which are only tangental to a specific assertion. Or especially which are asked from obstrustification and ignorance.

I think that the way to proceed in keeping this discussion on the point of my assertion regarding Apollo 13 tempreture is to reserch the NASA site's info on the spacecraft's cooling systems to find out what their heat exchange capacity is in BTU if available, research the heat output of the internal sources of heat in BTU (electrical and biological) if available and subtract the internal sources from the capacity to find the excess capacity of the system. Presume that they are not going to lift a 1000 pound 100,000 BTU heat exchanger up there if a 10,000 BTU 50 pounder will do. Then presume that the excess "unused" capacity is designed in to manage solar heating.

If the excess is far greater than a reasonable amount of unused margin, as determined by comparing it to other margins (if available) designed into the craft, that will further support my assertion. If the excess is a reasonable amount of unused margin as determined by comparing it to other margins designed into the craft, that will discourage my assertion.

Those are the thermodynamic numbers appropriate for applicability, directness and simplicity to this discussion and that is the research I will do. I will post the well anotated (via short range link) results when I compile them. You are welcome to do the research as well if you don't trust my schoolarship.

Other than that, an impartialy conducted experiment comprised of launching an Apollo spacecraft with it's equiptment turned off and three men aboard into trans lunar orbit and measuring the tempreture would also apply. It would be much more complex, as many other evaluative approaches such as some of the ones posted are. But it would be more accurate, applicable and direct than some posted as well. Because some formulas posted require the support of numbers from materials and structures that are not available and/or are not accurate or applicable.

Regards,
SAMU

PS

As I said in my initial post. Food for thought.

<font size=-1>[ This Message was edited by: SAMU on 2001-11-06 22:06 ]</font>

Obviously, you were not here 6 - 8 months ago for the Fox TV moon hoax flap. Every point that you have brought up (thinking it was original) has hashed and rehashed ad nauseum. The research has been done. The answers have been found. The responses you have been getting are the result of that research. You have three choices:
1) Accept the word of those who have already done the digging.
2) Follow the links that have been provided (the results of the research) and discover the truth that others have found.
3) Keep your head and the sand.

Notice that having others do the research (again) for you is not one of the options.

__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

I must also note that grass reflects only about 13% of the green wavelength light it receives, but the human eye is most sensitive in the green range (that's why "night vision" stuff like they showed on TV in the Gulf War and such is green), so it appears brighter than an object reflecting 13% of red or blue (or other wavelength) light.

__________________
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

How much you wanna bet he's gonna pick #3? [img]/phpBB/images/smiles/icon_evil.gif[/img] [img]/phpBB/images/smiles/icon_evil.gif[/img] [img]/phpBB/images/smiles/icon_smile.gif[/img]

__________________
"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]

SAMU said:
Yet you seem to expect people to be able to research any question as if it is the specific assertion. You have a specific complaint about the heat loads and cooling capabilities of the Apollo spacecraft. Other people want to know why the cameras took such good pictures and weren't over or underexposed, or how the lunar rover fit inside the lunar lander, or how much fuel was required, or why the descent engine of the LM could provide 10,000 lb thrust but the ascent engine could only provide 3000 lb. One guy came here arguing that the space suits could not have kept the astronauts cool because he didn't know anything about how they worked but knew space is a vacuum and so they couldn't cool by convection. So while you have one main question, everyone is coming asking their "one" main question and expecting people here to be able to answer those questions off the cuff. There is a surprising amount of information available, that I've only become aware of in the past 2 years. Some really good technical descriptions and data. On the other hand, I keep finding questions to even more specific levels that I haven't found the data for. Your's is one of those questions.

I will note you are passing on discussing the "tangential" issues, without actually conceding that people here know what they're talking about even if you don't. That is a depressingly common occurrence. Someone asks a technical question, then doesn't accept the answer when it comes from knowledgable professionals who studied the topic in college to get degrees in order to understand it, and then apply that knowledge in their career. You seem aware that not everyone can be an expert in everything. However, you don't seem willing to accept that other people are experts in those areas and are giving you the answer. When a person (such as we have had in the past) comes in and says that everything we tell him about thermodynamics and space suit operations is suspect because we work for NASA (as a few people here do or have in some capacity), he is discounting the fact that all of the general principles being described are taught in engineering and physics classes around the world. It's kinda hard to lie about how physics works. But that's the position you seem to be putting us in when you won't accept how albedo and reflectivity and emissivity work and how material surface properties make all the difference. Or when you accuse NASA of faking the Apollo 13 flight including the explosion because the temperatures just happened to stay above freezing temperatures but were cold and not hot. Even after people have described why, you aren't happy and want to see the actual calculations the design engineers made 40+ years ago when designing the system. That just seems an unreasonable expectation to me.

Be that as it may, I tried to look through the usual references to find the numbers. No luck. I have a pretty good description of how the cooling system (environmental control system) on the LM worked that I can reference. It lists water pressures in the system, but not heating/cooling loads.

http://www.apollosaturn.com/Lmnr/ec.htm

I will note this paragraph down at the bottom of that page:

You will note they reference the cooling systems are designed to cool the electronics and equipment separate from the structure of the vehicle itself. This implies heavily that the cooling system was built to handle electronic equipment heat loads, not heat from the crew or from solar radiation on the structure. Which is what we've already said.

I'll look a little more and see what else I can turn up, but without doing some hairy calculations I don't know that you'll get the answers you want.