Al Johnston
"Cheer up!" they said, "It could be worse!" So I did, and it was.
Posts: 1,453
|
Post by Al Johnston on Aug 18, 2007 7:19:58 GMT -4
In fact, when the moon is fully eclipsed by Earth and a deep-red colour, a properly-exposed photo of it still doesn't show any stars. Not quite, although this may be Venus... Overall though, the point stands: there are a lot more stars in that field of view, you just can't see them at that exposure.
|
|
|
Post by ka9q on May 1, 2008 15:11:01 GMT -4
Lunar module looks too flimsy to work. I'd worked on some small ham radio communication satellites before I saw the LM close up in the Smithsonian, so I was already familiar with spacecraft design and thermal control. So it didn't even occur to me that people might think the thermal blanketing was the actual LM structure. Is this common?
|
|
|
Post by Joe Durnavich on May 1, 2008 15:51:37 GMT -4
I'd worked on some small ham radio communication satellites before I saw the LM close up in the Smithsonian, so I was already familiar with spacecraft design and thermal control.
Are you the KA9Q of, well, the KA9Q TCP/IP package from way back when?
|
|
|
Post by ka9q on May 1, 2008 16:02:49 GMT -4
It's probably dust on the prints or, more likely, the glass when they were scanned I noticed these artifacts a while ago and gave them some thought. I don't think they're scanner artifacts as they appear in different locations. Also, these are Ektachrome slides, so dust would appear black, not white. At first I also thought they might be high energy cosmic ray particles, but as pointed out here some should be streaked in random directions. Also, I'd expect particles to be energetic enough to penetrate several layers of film on the spool in the magazine, so we should see artifacts that line up appropriately in consecutive pictures. A closer inspection of the artifacts showed that some were round and others were elongated -- always vertically, parallel to the sides of the image even if the camera was turned. Furthermore, all but the brightest artifacts were blue in color; the brightest were white. I note that the outermost layer in Ektachrome emulsion is the blue-sensitive layer. When exposed to blue light, it develops to metallic silver which is then bleached away. The remaining unexposed halide is developed into yellow dye (blue's complementary color). So if the silver halide in the blue layer is removed, either by exposure to light and development or by a physical scratch, there'll be no yellow dye. And you'll end up with a blue spot. If all three layers of emulsion are removed, the area will develop clear, i.e., white. So his strongly suggests one of two things: contamination of a roller or guide in the camera or magazine, or static discharges in those same places as the film was wound. The moon is bone dry, and its dust is known to be very fine and abrasive with a nasty habit of getting into everything. All the astronauts complained about it. So either theory is plausible, but I lean towards the dust contamination theory because I'd expect all but the very weakest static discharge to expose more than just the outer blue layer of the film.
|
|
|
Post by ka9q on May 1, 2008 16:03:13 GMT -4
I'd worked on some small ham radio communication satellites before I saw the LM close up in the Smithsonian, so I was already familiar with spacecraft design and thermal control.Are you the KA9Q of, well, the KA9Q TCP/IP package from way back when? Yup, that's me!
|
|
|
Post by Joe Durnavich on May 1, 2008 17:19:38 GMT -4
Yup, that's me!
Hey, that's neat. An important figure from personal computer history graces our presence! These youngsters today have no idea of the hell it took to get networking going on PCs. (And with that, I officially become an old man complaining about how things were back in my day.)
|
|
|
Post by Joe Durnavich on May 1, 2008 17:25:04 GMT -4
I noticed these artifacts a while ago and gave them some thought. I don't think they're scanner artifacts as they appear in different locations. Also, these are Ektachrome slides, so dust would appear black, not white.
That may be true for the color slides, but the post you referred to shows some of the 500 mm photography done by Apollo 15, which was on black-and-white negative stock. The quality of the scans available from the LPI catalog tends to be of a poorer quality with a good deal of dust and compresssion artifacts. That's consistent of course with the purpose to present a comprehensive catalog of the images that are available.
|
|
|
Post by Ginnie on May 1, 2008 17:45:52 GMT -4
I officially become an old man complaining about how things were back in my day
And I guess it's either "good" or "bad" depending on what mood you're in?
I long for knobs that turn, Vu meters and bass and treble controls.
|
|
|
Post by Count Zero on May 2, 2008 2:43:00 GMT -4
So it didn't even occur to me that people might think the thermal blanketing was the actual LM structure. Is this common? Quite. Of course, by the same arguement, our shirts are what holds us all upright...
|
|
Bob B.
Bob the Excel Guru?
Posts: 3,072
|
Post by Bob B. on May 2, 2008 8:56:13 GMT -4
So it didn't even occur to me that people might think the thermal blanketing was the actual LM structure. Is this common?Yes, it is very common. HBs frequently complain about the supposed 'sloppy' appearance of the LM's exterior. Of course they are ignorant about how and why the LM was built the way it was. They're idea of what a spacecraft should look like comes from sci-fi television. They don't realize that the LM's ascent stage was covered with a thin micrometeoroid layer supported by standoff brackets. They are unaware that Mylar insulation is crinkled on purpose to improve its insulation properties. They don't know that tape is an ideal fastener because it provides a lightweight continuous joint. Sadly they don't want to learn any of this because it conflicts with their desired belief that the LM was faked. We also see this type argument regarding the spacesuits. The HBs are unaware of the multilayered construction of the EMU. They think the outer thermal and micrometeoroid garment is the pressure garment and then complain when it doesn't look like a pressure garment should. Willful ignorance is a prerequisite for persistent belief in the moon landing hoax. * * Edited to add the word "persistent".
|
|
|
Post by AtomicDog on May 2, 2008 10:38:58 GMT -4
I just saw the "Spider" episode of From The Earth To The Moon again last night. (Rest in peace, John Shea.)
It really galls me to see such a robust and meticulously engineered vehicle referred to by the HBs as "flimsy" and "untested".
|
|
|
Post by JayUtah on May 2, 2008 13:25:36 GMT -4
Yes, unfortunately naive expectations are the norm when evaluating Apollo construction, especially with the LM.
Science fiction has given us a number of beautiful, inspiring spacecraft -- many of them wholly impractical. Galactica does an excellent job of placing us in a warship setting for dramatic purposes, but only by mimicking what we have come to expect as the construction associated with battle machinery. Real spacecraft construction simply can't afford to let appearance be more than about a third-order concern.
There is a natural appeal to intuition. Most conspiracy theorists seem to be male, and most males want to be considered adept at construction. The maxim seems to be, "I've built a guest room addition onto my house, therefore I ought to know how to build a spacecraft." Well, yes and no. If you've mastered one technique of construction, chances are you'll appreciate the principles of another. In a certain sense, a screw is a screw and a weld is a weld. But just because one technique eschews duct tape as "ghetto" doesn't mean another technique can't adopt it as best practice.
Modern balloon framing for residential construction is largely a matter of recipe. Buy standard-sized lumber and use standardized techniques, and you probably can't go wrong. The reason you can't go wrong is because the margins in that method are so absurdly broad that you really have to try hard to exceed them. But spacecraft construction -- and aerospace in general -- can't afford such luxurious margins and therefore can't rely on cookie-cutter methods. Space engineering often has to go back to basic principles and engineer structures, coatings, and control methods from the ground up.
In short, if you haven't studied spacecraft construction, then you can't really speak knowledgeably about whether a particular spacecraft is properly constructed. You can basically only say that it isn't built like a battleship or a birdhouse, which ought to be obvious.
But most importantly, conspiracists don't want to delve into the details not because they're incapable of understanding them, but because handwaving is so much easier and effective on this point. "Just look at it! Who could believe such a contraption could actually fly?"
That's not to say conspiracists won't ever delve. But they quickly learn where and when to delve. On topics such as spacecraft construction, where there are experts to be had, they know they can't hold their own. If they happen to get tangled up in someone who knows aerospace construction, they'll very quickly get in over their heads -- visibly so. So staying at the high level avoids revealing anything that might be testable.
But on topics such as human motivations or rumor, they'll happily delve because there isn't any hard and fast closure. You can argue forever on whether someone "would have" done something. That ties up the discussion in endless circling, conjecture, and counter-conjecture which distracts from the factual aspects -- if any -- of their claims. Conspiracy theorists would much rather speculate about why they think someone would have done something rather than look at the evidence that it was or wasn't done.
Over at BAUT a couple of weeks ago there was a poster who demanded the "factory drawings" of the lunar module, so that he could verify for himself whether it was built correctly. He had what he said were specific questions about its appearance and construction methods. Of course there were a number of people ready, willing, and able to discuss the LM construction with him, but he was dead-set on seeing "the plans." He was given references to such classics as LM-5 Structures Manual and the Lunar Module Operator's Handbook. But these he deemed insufficient because they did not, in his opinion, provide sufficient detail. But the questions he asked were answered in these materials. And he would not say what detail he expected in the "factory drawings" that were not provided by the existing references, nor where he acquired the skills necessary to interpret low-level engineering and assembly drawings.
Clearly he didn't really want the information in those drawings; he merely wanted to hammer home the notion that they had been destroyed and/or were no longer easily available to him. He was much happier with the notion that crucial design information was allegedly being concealed than with the notion that there weren't actually any specific questions left unanswered about the lunar module. That sort of handwaving trumping-up of suspicion is what characterizes the conspiracist approach to many things.
|
|
Jason
Pluto
May all your hits be crits
Posts: 5,579
|
Post by Jason on May 2, 2008 13:46:21 GMT -4
Out of curiosity, how does having the Mylar crinkled improve its efficiency at insulation?
|
|
|
Post by Grand Lunar on May 2, 2008 13:54:17 GMT -4
I'm willing to bet that it allows for more efficent reflection of heat, by not having it smooth.
That's only a guess of mine, though. I do not claim to be an expert at heat transfer. Except in internal combustion engines. ;D
Okay, not even that. More of a novice.
|
|
Bob B.
Bob the Excel Guru?
Posts: 3,072
|
Post by Bob B. on May 2, 2008 14:13:15 GMT -4
Out of curiosity, how does having the Mylar crinkled improve its efficiency at insulation? In NASA own words: "The crinkling provides a path for venting, and minimizes contact conductance between the layers."This post gives a more complete description of the LM's thermal and micrometeoroid shield (from the Apollo Saturn News Reference).
|
|