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Post by ka9q on Jul 9, 2008 7:46:12 GMT -4
I'm seeing mention in some HB boards of yet another "anomaly" that supposedly proves a hoax. I haven't been able to find an actual statement of the claim, but it seems to have something to do with the "air conditioning system" in the lunar module being operated by batteries.
Anybody know what that one is about?
The entire LM, including the environmental control system, was operated by batteries. Nearly a tonne of them using silver-zinc chemistry with no provision for recharging. The LM, like the PLSS, cooled itself by vaporizing water into space, carrying heat with it. This water was the cruicial consumable in the Apollo 13 lifeboat mission.
Perhaps the claim is that batteries could not possibly have operated a conventional electric air conditioner for the required period of time?
The actual cooling mechanism is well documented, but this is just the kind of silly, ignorant crap we're used to hearing from the HB's.
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Bob B.
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Post by Bob B. on Jul 9, 2008 9:47:33 GMT -4
My understanding is that all the LM's "air conditioning" system needed was a pump to circulate the coolant. Yes, it ran off batteries, but it didn't require much energy. When the HBs hear "air conditioning" their minds run wild imagining some sort of energy hog system like we use to cool our homes. Their claims stem from ignorance. (edit) By the way, this is not the appropriate section of the forum for this topic. The "Clavius Moon Base" section should be use only for topics specifically relating to JayUtah's Clavius web site. This should probably be in either "The Hoax Theory" or "The Reality of Apollo" sections.
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Post by JayUtah on Jul 9, 2008 15:16:17 GMT -4
Bob has likely hit the nail mostly on the head. Conspiracists argue from several wrong assumptions.
First is that by "air conditioner" in the LM's case (and in the suit's case) is meant the familiar vapor-compression cycle by which refrigeration occurs in domestic air conditioners and refrigerators. That apparatus indeed require considerable application of external energy in order to effect the compression side of the cycle.
But of course the LM cooling system did not work by those principles. Heat rejection was by radiation, supplemented by an open-cycle sublimator where necessary. Radiation is an entirely passive process; sublimation is almost entirely passive, if you happen to have a vacuum handy. In each case a refrigerant must be circulated in order to convey heat from the cabin and electrical equipment to the heat-rejection elements. But unlike the vapor-compression cycle, there is no costly recompression of the refrigerant. The circulation of the refrigerant and the feedwater for the sublimator require only nominal pumping at manageable flow rates.
Radiation is not generally as effective in an Earth ambient environment because of the convective heat load upon the radiator. Sublimation is not effective in an Earth ambient environment because suitable sublimands are not plentiful, and the entire design incorporates a consumable. Hence the vapor-compression cycle is the most effective and efficient cooling technology in the Earth environment for consumer purposes. Informal references to "air conditioner" in NASA literature or among conspiracists does not imply that the design of the LM's cooling system was anything other than what has been more carefully documented elsewhere.
Second, conspiracists invoke the alleged 250 F daylight temperature of the lunar surface to imply that an atmospheric (or similar) ambient temperature must persist. This is used to suggest that the ambient-imposed heat load on astronauts and equipment must be ferocious, requiring more prodigious heat rejection than can be accomplished by a battery-powered unit of any design. This too is fundamentally ignorant of basic thermodynamics, but it nevertheless feeds the misconception.
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Post by Grand Lunar on Jul 9, 2008 21:54:22 GMT -4
Also along these lines, when HBs hear "batteries", they think of the lead-acid batteries used in automotive technology. They do not know of, or care to research, the different types of batteries that exist.
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Jason
Pluto
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Post by Jason on Jul 10, 2008 11:05:02 GMT -4
In today's world of cell-phones and ipods, can anyone really be ignorant enough to think that "battery" always means "lead-acid cell"?
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Post by grashtel on Jul 10, 2008 11:46:10 GMT -4
In today's world of cell-phones and ipods, can anyone really be ignorant enough to think that "battery" always means "lead-acid cell"? I have a horrible feeling that the answer to that question is yes considering how dumb people can be. Also Apollo was back in the 60s way before they had cellphones and ipods so its obvious that their battery technology sucked (except to people who actually know about battery technology).
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Post by Grand Lunar on Jul 11, 2008 20:03:46 GMT -4
In today's world of cell-phones and ipods, can anyone really be ignorant enough to think that "battery" always means "lead-acid cell"? I have a horrible feeling that the answer to that question is yes considering how dumb people can be. Also Apollo was back in the 60s way before they had cellphones and ipods so its obvious that their battery technology sucked (except to people who don't actually know about battery technology). To add to this, I read a comment by an HB that prompted my observation here. I don't recall who said it, though. Perhaps someone else with more dealings have seen this person? Anyway, the HB seemed to believe that the LM batteries were like those in a car, because they person said that car batteries go dead in few hours time, and so did not see how the LM could've been powered by batteries for the amount of time it spent on the lunar surface. This person also must never have heard of deep cycle lead acid batteries.
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Jason
Pluto
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Post by Jason on Jul 11, 2008 21:21:18 GMT -4
Anyway, the HB seemed to believe that the LM batteries were like those in a car, because they person said that car batteries go dead in few hours time, and so did not see how the LM could've been powered by batteries for the amount of time it spent on the lunar surface. This person also must never have heard of deep cycle lead acid batteries. I wonder how those U-boats in WWs I and II were so effective when they could only power their engines for a few hours time?
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Post by Grand Lunar on Jul 12, 2008 8:43:48 GMT -4
Only goes to show HBs awareness of technology.
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Post by ka9q on Jul 15, 2008 4:16:01 GMT -4
I wonder how those U-boats in WWs I and II were so effective when they could only power their engines for a few hours time? That's power their motors for a few hours time. The prime mover was a diesel engine driving a generator. U-boats spent most of their time on or just below the surface where they could use a snorkel. Battery power was only needed when diving, and they only did that when attacking. Both range and speed were greatly limited on batteries, but they were effective enough. This is really getting off topic...
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Bob B.
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Post by Bob B. on Jul 15, 2008 8:34:52 GMT -4
... and they only did that when attacking. Or when evading. Actually, whenever possible, U-boats would attack on the surface using their deck gun. 3-inch shells are a lot cheaper and more plentiful than torpedoes, and very effective against merchant ships. As the allies adjusted their tactics and began protecting merchant convoys with naval escorts, surface attacks became a rarity.
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Jason
Pluto
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Post by Jason on Jul 15, 2008 10:49:50 GMT -4
I know quite a bit about U-boats. My point was twofold - that batteries were useful as far back as the 19-teens and that hoax believers tend not to know anything about battery technology.
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Post by ka9q on Sept 22, 2011 18:26:11 GMT -4
Also Apollo was back in the 60s way before they had cellphones and ipods so its obvious that their battery technology sucked (except to people who don't actually know about battery technology). The standard Apollo-Saturn battery was silver/zinc. Zinc was the fuel (the electron donor) and silver oxide was the oxidizer (the electron sink). The electrolyte was potassium hydroxide in water. Silver-zinc batteries have surprisingly good energy densities (watt-hours per kg of mass). Almost as good as lithium-ion, in fact. But they have two main disadvantages. The first is a poor cycle life when used as a secondary (rechargeable) battery, typically measured in single digits. This was not a serious problem for Apollo; only the CM entry batteries were ever recharged, and then only a few times during a mission. No other battery, including those on the Saturn V and the LM, was ever recharged. The other drawback to silver-zinc chemistry should be fairly obvious, although it was not a major consideration for the government-funded Apollo project. Nowadays one would probably use lithium metal/thionyl chloride batteries for primary applications and either lithium ion or nickel-hydrogen for rechargeable batteries depending on the life cycle requirements.
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Post by Mr Gorsky on Sept 28, 2011 3:45:20 GMT -4
In today's world of cell-phones and ipods, can anyone really be ignorant enough to think that "battery" always means "lead-acid cell"? In a recent discussion about smartphones, an acquaintance of mine (who I thought was relatively tech-savvy) waxed lyrical about his iPhone. One of the others said he would never buy an iPhone until he was allowed to change the battery himself, at which point he chimed in to state that the iPhone "... doesn't have a battery, you just charge the phone itself".
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Post by echnaton on Sept 28, 2011 9:29:29 GMT -4
the iPhone "... doesn't have a battery, you just charge the phone itself". Although a guffaw might have been the natural response, I hope you were able to restrain yourself to a giggle. I've never understood the "can't change the battery" objection. The iPhone is designed to operate without any maintenance for the length of time that most purchasers are expected to use it, a little more than two years. I don't know any one that purchased an original iPhone that is still using it, they have all upgraded to smarter, faster phones. Besides it just doesn't stop working and will last far longer than two years with the same battery for most users. Any additional expense or complexity to make the battery changeable would make it cost more and not serve the intended customer well. The idea that things should be built to be maintained for extended use is fine, but it does not apply equally to all goods. Most products are engineered with an array of constraints that reduce the potential life span, either to meet a price point or because of projected functional obsolescence. An original iPhone has past the point of functional obsolescence.
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