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?