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Post by inconceivable on Jul 4, 2007 19:28:38 GMT -4
So what if an entire Area 51 sized building was filled and sealed with Helium for the purpose of filming some Apollo footage. In a sense a clean room was created so that dust and dirt could be more easily simulated. Dust and dirt sink faster in Helium than in normal air. Now the Apollo suits consist of an inner suit and outer suit. Suppose between the inner suit and the outer suit Helium was inserted to lighted the affects of the suit. How would the astronauts look hopping around?
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Post by james on Jul 4, 2007 20:06:13 GMT -4
I'm pretty sure the effect would be little to none. An Apollo space suit itself weighs about 80lbs if I remember right. It would take a fair bit of helium to get one to appear as though they are in 1/6th of earth's gravity.
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Bob B.
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Post by Bob B. on Jul 4, 2007 20:07:34 GMT -4
So what if an entire Area 51 sized building... How big is that? Is it as big as the scenes we see in the Apollo video? Dust and dirt sink faster in Helium than in normal air. True. How does this eliminate aerosolation? Now the Apollo suits consist of an inner suit and outer suit. Suppose between the inner suit and the outer suit Helium was inserted to lighted the affects of the suit. Negligible weight difference. How would the astronauts look hopping around? It wouldn't affect it at all. Helium creates buoyancy in air because it is less dense than air. But in your scenario you have helium both inside and outside the suit, therefore there is no buoyancy.
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Post by Tanalia on Jul 4, 2007 20:11:41 GMT -4
Helium (for instance, in a balloon) rises because is it lighter than the surrounding air. A helium-filled balloon in a helium-filled room would float down the same way an air-filled balloon does normally, and a helium "augmented" suit in a helium-filled room would similarly provide no benefit.
As for the benefit of helium vs normal air, the small volume of helium, even assuming the PLSS was hollow and filled with helium too (since if it was being faked we assume they wouldn't need real life support), would only decrease their weight by a couple ounces.
And while dust would settle faster, it would still form noticeable clouds and be affected by any breeze or eddies.
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Bob B.
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Post by Bob B. on Jul 4, 2007 20:17:45 GMT -4
(since if it was being faked we assume they wouldn't need real life support) They would still need some sort of breathing apparatus being in a helium atmosphere. And they would probably still need some sort of cooling system being in a sealed suit.
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Post by Tanalia on Jul 4, 2007 20:40:07 GMT -4
My second case was not in a helium atmosphere (though maybe I didn't spell that out clearly enough), since the helium suit in a helium atmosphere scenario provides no benefit. I was attempting to follow the idea of making the suit as light as possible from the point of an HB, assuming that if it was normal air outside (so the helium would have some effect), the suit wouldn't have to be sealed against the outside air (only sealed to make a helium-filled shell), and small circulating fans plus keeping the "set" well air-conditioned would probably suffice. Even so, the suit would still be heavy and bulky, and the limited amount of space you could fill with helium doesn't help enough to be worthwhile -- you would be better off skipping the helium and using an unsealed suit.
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Post by nomuse on Jul 4, 2007 21:35:23 GMT -4
Naw. They call it a vacuum suit, right? So take all the air out of it. Be lighter than even helium.
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Bob B.
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Post by Bob B. on Jul 4, 2007 21:45:06 GMT -4
My second case was not in a helium atmosphere... Ah, yes, I see that now. Sorry, my mistake.
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MarkS
Earth
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Post by MarkS on Jul 4, 2007 22:06:47 GMT -4
Wouldn't they need to empty the chamber to perform the feather and hammer experiment?
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Post by JayUtah on Jul 5, 2007 1:18:51 GMT -4
The buildings at Area 51 are not any larger than any other flight line's. Norton AFB is another site commonly proposed as a shooting location. Both scenarios involve buildings that started life as airplane hangars. Sealing an aircraft hangar gas-tight would probably be no easier that building a new building specifically to be gas-tight. Airplane hangars are notoriously drafty, unsealed structures.
Since helium is a very small molecule, it's very hard to design seals for it that will hold up at such a large scale with acceptable leakage. Latex balloons don't hold helium for very long. Mylar balloons hold it for longer. Blimps top themselves off with onboard compressed sources. If you need, say, five million cubic meters of the stuff, in practice you'll need much more than that to compensate for leakage. You'll also need a slight positive pressure, because you can't tolerate air leaking in -- it will congregate near the floor where the effects will occur and ruin them.
Could it be done as a matter of engineering? Possibly, but I wouldn't start with an existing structure. I'd fabricate one of those large inflatable buildings -- essentially a big giant gas bag. Anchor it to the ground and then enter through an underground airlock that forms a sort of sump for heavier gases to accumulate. The problem with any fabrication method is scale -- a few of the Apollo shots demonstrably occupy an area hundreds of meters square. At that size you'd have to raise the internal pressure to maintain the shape, which then eats into your mass density advantage. The alternative is to support the bag by means of an external structure -- a series of trusses spanning hundreds of meters. So then basically you have a shrink-wrapped football stadium.
I'm still not sure you can get rid of enough aerosol tendency by using a lighter gas. Aerosols are easily revealed even slightly in lighting designs that light foregrounds brightly against a dark background. Your tolerances here are very, very small. And by adding any gas at all you introduce other fluid effects, such as blowing flags.
As for filling the internal space between the space-suit layers with helium, that wouldn't produce a significant amount of buoyancy. Helium just isn't that buoyant. One of my favorite party tricks is to tie a helium-filled Latex balloon string to an empty soda can and drip water into it until neutral buoyancy is achieved. Kids love seeing a balloon essentially motionless, neither rising nor falling. It takes suprisingly little water in the soda can to achieve neutral buoyancy with the typical party balloon.
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Post by Count Zero on Jul 5, 2007 1:19:54 GMT -4
Wouldn't they need to empty the chamber to perform the feather and hammer experiment?
...which gets us back to fundamental fact that is not stressed enough:
The "hammer & feather" experiment, like nearly every other piece of video from Apollo, is part of a MUCH longer continuous shot which shows a variety of phenomena which cannot all be consistent with a single hoaxing hypothesis.
For example, HBs have pointed to some clips and said the astronauts are bouncing on strings, yet in the complete video, the same astronauts move close enough to the camera that you can clearly see that there are no strings.
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Post by JayUtah on Jul 5, 2007 1:25:29 GMT -4
Agreed. This is where the convenience clips on NASA web sites, on YouTube, and in conspiracy videos simply do not suffice. People are bound to think that's how the original material occurs, and so common techniques could be employed that only have to hold up for a few seconds.
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furi
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Post by furi on Jul 5, 2007 8:16:52 GMT -4
As has been stated before, the buoyancy effect exhibited by He in Air would have no impact in an He atmosphere,
The drag effects of atmosphere would be lessened but not eliminated, aerosolisation and vortices would still be in evidence.
however this theory would introduce a whole host of other problems,
The Enviroment suits would be required to function, with cooling and life support, and the cooling system as documented would not function, so would need a larger radiative system to dump the excess heat the exhalations of the Astronauts/Film crew would need to be sumped locally or condensed and collected through a rebreather system as these heavier gasses would cascade to the floor possibly creating disturbance.
the other problem is that you would effectively have a closed system, which is having Heat Pumped into it at a great rate due to Body activity, electronic systems and Lighting, Placing small fans within the enviroment would just increase the heat input as there is no cooling, unless you intend the fans to move air over a cooled surface, this however would require some serious air conditioning sytems, even with large heat dumps (pumped fluid cooling systems under floor in support structures and props) the cooling would be huge but not technically insurmountable. However you would now have a serious number of convection systems set up, which could move dust and materials.
The easier solution would be to lie and say the Lunar rover did not work as performed & not to do any of the Lunar rover footage/experiments, or to change the characteristics of the lunar soil, to one more friendly to simulation
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Post by Grand Lunar on Jul 5, 2007 8:17:42 GMT -4
With the technology needed to create this hypothetical enviroment, it seems to me it'd be easier, and less of a headache, to just GO to the moon.
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Post by JayUtah on Jul 5, 2007 9:11:59 GMT -4
A great deal of equipment used in filmmaking -- lighting instruments especially -- are cooled by either natural or forced convection. Putting that equipment into an environment with lesser heat-transfer capacity won't work.
Now that you have an atmosphere that won't support life, your actors will indeed need practical closed-loop suits instead of mere costumes, and that wears pretty heavy for those hours-long single takes. But your crew will also need respirators and some way to deal with the prodigious amount of carbon dioxide everyone will exhale over the course of filming.
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