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Post by gwiz on Feb 22, 2012 5:53:48 GMT -4
This was in the early 1970s, and of course the United States would be completely metric/SI in just a few years so why bother learning obsolete stuff? Even if he'd been right about the US going metric, he'd still be wrong about ignoring the Imperial units, because obsolete and obsolescent are not the same. The UK engineering industry switched to SI units four decades back, but there are still products around that pre-date the switch, so I had to be able to work in both systems throughout my career.
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Post by gwiz on Feb 21, 2012 6:19:07 GMT -4
After the fire, NASA decided to adopt a less obtuse numbering system that made each mission seemed more glamorous leading to Apollo 501 being named Apollo 4. The three missions already flown would have been Apollos 1, 2 and 3, but because the widows campaigned to let Apollo 1 be the official name of Grissom's moribund flight, that happened and the first three were never officially renamed from their Apollo 201, 202 and 203 designations. Hence why there is no Apollo 2 or 3. Not quite right. The flown missions were never re-numbered. Apollo 2 and 3 were the missions cancelled after the Apollo 1 fire, for which crews had been assigned. NASA didn't really explain this, which is why there are various guesses about renumbered flown missions floating about.
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Post by gwiz on Feb 17, 2012 12:04:07 GMT -4
After the exhaust gas initially contacts the lunar surface, a cm3 area of gas at the center will than move outward, say 1 cm, as it does a cm3 of gas must be combined into this cm3 area as a result of the continued flow of exhaust gas, this additional cm3 of gas must be compressed into the original cm3 area and so on until the original cm3 of gas reaches the perimeter of the plume, 137 cm from the center. The original cm3 of exhaust gas will now have accumulated 138 cm3 of exhaust gas compressed into a 1 cm3 area. Just to show that this argument doesn't make sense, try doing it in inches instead of cm. The radius of the plume becomes 54 inches, so by your argument the density increase is a factor of 55 instead of a factor 138. Now use feet, and radius becomes 4.5 ft so the density increase is only 5.5. Now use metres... An argument that gives an answer for a non-dimensional factor based on the dimensional units used is obviously incorrect.
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Post by gwiz on Feb 1, 2012 6:29:39 GMT -4
Hey, does anybody know the inclinations of the lunar orbits used during each Apollo mission? This is surprisingly hard to find, as it's not in Apollo by the Numbers. I'm looking for the lunar orbit inclinations of the CSMs for each mission when the LMs were jettisoned, specifically for Apollos 11 and 16, the two missions that abandoned their LMs in lunar orbit. The following figures for final LM orbits are from the DRA Table of Space Vehicles. Note the orbits are retrograde, so subtract from 180 deg to get a more familiar number. Apollo 11 178.7 Apollo 12 165.6 Apollo 14 166 Apollo 15 151.28 Apollo 16 169.3 Apollo 17 159.9
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Post by gwiz on Jan 29, 2012 14:14:28 GMT -4
Is it correct to say the exhaust follows the path of least resistance? It seems to me that flowing radially outwards along the surface like you say would be easier than digging a crater into solid rock or going straight back up and fighting against gravity and the rest of the exhaust coming down. Basically, provided the surface is strong enough, it turns the jet molecules through ninety degrees so they can flow outwards. After that, there's nothing to turn the jet any more and they just keep going. I think Bob(?) has shown that the pressure in the jet was low, so it is only going to shift loose material. The core of the jet, all of it at the nozzle exit but diminishing in diameter as it goes downwards, is supersonic which means no pressure wave can travel against the flow.
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Post by gwiz on Jan 29, 2012 6:50:29 GMT -4
Yes, I have heard of back pressure. However, you're the first person who has suggested that it is insurmountable. How does a Harrier land, if it cannot be manipulated so that the weight of the vehicle exceeds any upward force? As playdor wont be answering your question, here's my shot at it. Basically, when a jet strikes a surface, it flows radially outward along the surface. This is what happens with the single nozzle of the LM, and it doesn't create significant back-pressure. In an atmosphere, the outflow actually induces a flow in the air between itself and the aircraft that sucks the aircraft down. The four nozzles of the Harrier are a bit different, since in the region between the nozzles, the outflows from the individual nozzles are inflows from the point of view of the aircraft. This means that the flows converge and form a rising plume or fountain from the centre. This impinges on the underside of the aircraft, so there is a back-pressure that pushes the aircraft up. This is actually a valuable feature for countering the suck-down effect and braking the descent. on-target-aviation.com/Assetts/images/Harrier_HOVER%20DIAGRAM%20CAG.jpgThe later variants of the Harrier had vanes on the undersurface to contain the plume and add to the effect. lh5.ggpht.com/_cTaLGgz4Ru8/SFC_X7x1ClI/AAAAAAAAGCk/3CTZYMOrU3g/AV8B.jpg
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Post by gwiz on Jan 4, 2012 11:05:14 GMT -4
How much harder is it to get a rocket to the Moon... Seeing that the first Moon launch attempts, US and Russian, were less than a year after Sputnik 1, and that the Russians achieved their first success within two years, not very much.
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Post by gwiz on Dec 20, 2011 7:37:17 GMT -4
Completely wrong - many peolpe (including real experts) have tried to deny Pokrovsky's modeling work, but so far the attempts have been either laughable or just miserable. There's also Pokrovsky's argument based on the rate at which the second stage separates from the smoke cloud of the retros. This is again a geometrical mistake as, from the point of view used, the part of the cloud he claims is its leading edge is in reality expanding to the side in a way that makes it appear closer to the upper stage than the actual leading edge which is hidden from view.
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Post by gwiz on Dec 17, 2011 9:37:06 GMT -4
Didn't a school in Germany do some work here? Italy. I mentioned it in post #29 in this thread.
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Post by gwiz on Dec 17, 2011 7:15:20 GMT -4
The moon picture books published in early 1970s were either Disney kind of books with very bad quality pics (from a gravel pit and some with lamp lightning - some from Langley flight simulator) or geological books where only Metric/Panoramic camera pictures were used. Apart from National Geographic and Life, mentioned above, the technical magazine Aviation Week included a good quality colour section of photos after every mission. I don't think they missed any of the pictures that are now well known. For instance, the hoax theory's C-rock picture was used as an Av Week cover - curiously without the C, which is thus proved to be an artefact from a later scan. Within a few months of each mission, NASA published a preliminary science report with a lot more pictures, typically the ones of less general interest unless you are a geologist, such as the in situ documentation of the retrieved rocks. NASA also published a large format book - Apollo Expeditions to the Moon, 1975 - again with a lot of very good quality photos.
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Post by gwiz on Dec 16, 2011 12:25:27 GMT -4
There Is No Time Delay... On the contrary, not only is the time delay present but it is possible to measure the orbit of the moon from variations in the time delay. www.mendeley.com/research/echoes-moon-7/My, those hoaxers were clever, how on earth did they know what details Italian schoolchildren would think to examine decades later?
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Post by gwiz on Dec 15, 2011 9:49:59 GMT -4
The Skylab decay from orbit was extensively examined and agencies all over the world were making predictions. If the Skylab mass was different from the official NASA figure, this would have altered the ballistic coefficient and made all these predictions wildly inaccurate.
The fact that the decay was predicted accurately means the mass was as claimed
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Post by gwiz on Dec 14, 2011 12:50:13 GMT -4
Americans really want to tell that there was a competition to the moon between USA and SU - and USA won. US media has done everything to find smallest pieces of Soviet moon interests. Unfortunately this is not true. N-1 was a natural continuation to develop bigger and bigger rockets mostly for construction of space stations - it was not a moon rocket. It's depressing to compare such ignorance with the achievements of Boris Chertok, who died yesterday at the age of 99. He was at the core of the Soviet space program for decades, Sputnik, Vostok, Soyuz and their manned lunar programme.
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Post by gwiz on Dec 14, 2011 10:28:38 GMT -4
About Saturn V capacity problems there is another thread - about Pokrovsky theory (Russian spy organization analyzed the capacity of the rocket by using sophisticated electronic equipment 1969 at the Florida coast). All Pokrovsky proved is that Pokrovsky isn't very good at geometry.
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Post by gwiz on Dec 13, 2011 7:58:23 GMT -4
...Armstrong's answer is also inclusive with cislunar inner space and that when space is viewed from cislunar inner space, space is a deep black and the only visible objects are the earth the sun and the moon. Stars are not visible. Neil Armstrong says you can see stars:Playdor, this is basically what we've been telling you all along. In your quote, Armstrong says he didn't see stars on the lunar surface or cislunar space, both locations where he experienced continuous sunlight. However, in lunar orbit on the night side of the moon, with no sun visible, he could see stars.
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