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Thread: LM Hatch "Too Small" - A Debunking Project

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    LM Hatch "Too Small" - A Debunking Project

    Hi all! I'm working on a personal project building a LIDAR-based 3d scanner which I plan to use to take measurements from the ground of the LM-9 hatch opening and Cernan's practice suit at the Saturn V center at KSC (as seen in this photo: https://www.richasi.com/Snapshots/KS.../Floor-027.jpg ). I'll probably try to make a scan of Alan Shepard's flown A7L suit as well, but since it does not have any kind of PLSS attached I don't think it would be quite as useful for my plans (plus, filling in the back of the suit won't be readily doable whereas Cernan's suit is positioned such that I can easily position the scanner to get the back of the suit). My plan is to take the point clouds I generate of the LM and space suit and translate them into 3D meshes to test and demonstrate the space suit fitting through the lunar module hatch. The scan will look similar to this (though I am trying to make it look a lot less home-brew so that it doesn't raise too many eyebrows when I take it through security at the gate):
    https://www.youtube.com/watch?v=gCpCGkwwy8I
    The LIDAR I'm using has a 40 meter range (so it should easily reach the LM suspended above the floor) and I do plan to take multiple readings from multiple spots to combine the point clouds to maximize their density before translating them into meshes.

    My question is whether or not Cernan's practice suit (and especially the PLSS) is identically scaled to the flight article? Tentatively, I plan for the final step to take the 3D mesh of the space suit and rig up the joints so that I can import it into the Unity game engine as a player avatar for a VR app to then simulate egress from the lunar module mesh and show that it is possible to fit through the hatch. I guess I'm inspired in part by the mythbuster's Apollo hoax debunking episode, and in part by Nvidia's hoax busting tech demo, but before I execute on this plan I was wondering if someone could help me verify that the practice suit on display is truly to-scale with the suit Cernan wore on the moon? Of course it's not going to be pressurized, but given that I've heard it claimed that the Smithsonian deliberately made the figurines on display by their LM significantly smaller than life sized astronauts to hide the hatch being too small, I'm not concerned about quibbling over a few centimeters. I do want to make sure that the PLSS used in the practice suit isn't dramatically under-scale though.

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    Just a project update, today I finally got the lidar scanner fully assembled and working. I scanned a couple rooms with it over Bluetooth successfully. With luck I'll have my data on the LM very soon.

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    Wow. Are there really people out there who claim that the first image of Aldrin's egress shows a hatch that's too small for him to fit through?

    Grant Hutchison
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    Quote Originally Posted by grant hutchison View Post
    Wow. Are there really people out there who claim that the first image of Aldrin's egress shows a hatch that's too small for him to fit through?

    Grant Hutchison
    If they are, they must really be grasping at straws or scraping the bottom of the barrel for arguments in their favor. That hatch looks plenty big to me.

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    Quote Originally Posted by grant hutchison View Post
    Wow. Are there really people out there who claim that the first image of Aldrin's egress shows a hatch that's too small for him to fit through?

    Grant Hutchison
    I guess they think that was just a dummy, or that they used a different set that day?

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    I would suggest not putting this online. It is just giving the HBs attention which they appear to crave.

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    Amazingly, I'm pretty sure I remember hearing this argument in the mid-80's. In fact, I think it might have been the first time I encountered an HB.

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    The lack of logic in these claims does astound me.

    Effectively they're saying that the people supposedly filming the hoax footage didn't take the trouble to make sure the sets were consistent and properly constructed, and the props and continuity matched from scene to scene.

    Not to mention that the director didn't go "Cut! Somebody close that door. The flag's blowing all over the place. Let's go for another take..."
    Days spent at sea are not deducted from one's alloted span...
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    Quote Originally Posted by Hornblower View Post
    I would suggest not putting this online. It is just giving the HBs attention which they appear to crave.
    Point taken, but I'm afraid I've already gone too far and spent too much building this thing to not follow through on it. I'm also tentatively planning to use it to model the lunar rover they have on display to measure the angular size of the rover antenna as seen from the GCTA camera in order to measure the angular size of earth in a shot that had both in frame simultaneously, providing the data needed to refute the claim that earth wasn't large enough in the Apollo images of it (again an incredibly boneheaded mistake if it were true, yet it's frequently claimed).

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    Quote Originally Posted by grant hutchison View Post
    Wow. Are there really people out there who claim that the first image of Aldrin's egress shows a hatch that's too small for him to fit through?
    I'm not sure if that particular image was involved, but yes, I've seen the claim that the hatch was supposedly too small several times. Even here. When "here" was BAUT. Clavius has a page on it too.
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    Quote Originally Posted by grant hutchison View Post
    Wow. Are there really people out there who claim that the first image of Aldrin's egress shows a hatch that's too small for him to fit through?

    Grant Hutchison
    It is clear that the hatch size was a somewhat tight fit, IIRC each astronaut gave directions for his partner to adjust before moving through the doorway.

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    While sitting in the traditional place for pondering the imponderable*, I took an empty cardboard TP roll and flattened it; noting how much wider it was that way. If I remember my geometry correctly, the circumference of the roll is pi x diameter. The width of the flattened roll is half the circumference. Therefore the width of the flattened roll is pi/2 or ~1.57 times the diameter of the un-flattened cylinder. Thus the arms, legs & torso of a spacesuit laying flat would each be ~57% wider than they would be if someone was in the suit.

    My 2

    *Apologies to John Varley
    Last edited by Count Zero; 2018-Jan-03 at 08:16 PM. Reason: I changed π to pi for clarity

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    Quote Originally Posted by Count Zero View Post
    While sitting in the traditional place for pondering the imponderable*, I took an empty cardboard TP roll and flattened it; noting how much wider it was that way. If I remember my geometry correctly, the circumference of the roll is pi x diameter. The width of the flattened roll is half the circumference. Therefore the width of the flattened roll is pi/2 or ~1.57 times the diameter of the un-flattened cylinder. Thus the arms, legs & torso of a spacesuit laying flat would each be ~57% wider than they would be if someone was in the suit.

    My 2

    *Apologies to John Varley
    All true, but the suit I plan to measure is sitting upright on a headless dummy, not laying flat. I also plan to turn it into a model where the arms and legs can be moved as needed to pose the model appropriately exiting the hatch.

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    Just an update, I know it's been a month but the project isn't dead. In fact I plan to do the scans as soon as this weekend, if things work out. I reprogrammed the Arduino to take an average of 10 readings at each point to reduce noise in the data and also tightened up the pan/tilt bracket; a loose screw caused it to flop around a bit. The big hurdle to clear now is security. I have no idea if they'll let me in the gate with this thing. I've covered the wires running from the motors and laser with tubing, and although it hides the wires, I'm not sure it makes it look much less suspicious than it was before.
    http://h.dropcanvas.com/896ta/20171231_154200.jpg
    The rubber bands were temporary, everything is now secured with screws and Velcro. If anyone asks, it's just a 3D camera. Not sure if that will fly though. I'm really wishing I had a contact at the space center who could explain the situation and clear me through security, but as it stands I'm just going to have to take my chances and hope I don't cause a scare. If you hear about a suspicious device being detonated and a misguided nerd being hauled off to gitmo this weekend, it was nice knowing you all.

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    Wait! Before you go, there is one thing you absolutely must do!



    Will all your belongings to me.

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    Quote Originally Posted by NGCHunter View Post
    Just an update, I know it's been a month but the project isn't dead. In fact I plan to do the scans as soon as this weekend, if things work out. I reprogrammed the Arduino to take an average of 10 readings at each point to reduce noise in the data and also tightened up the pan/tilt bracket; a loose screw caused it to flop around a bit. The big hurdle to clear now is security. I have no idea if they'll let me in the gate with this thing. I've covered the wires running from the motors and laser with tubing, and although it hides the wires, I'm not sure it makes it look much less suspicious than it was before.
    http://h.dropcanvas.com/896ta/20171231_154200.jpg
    The rubber bands were temporary, everything is now secured with screws and Velcro. If anyone asks, it's just a 3D camera. Not sure if that will fly though. I'm really wishing I had a contact at the space center who could explain the situation and clear me through security, but as it stands I'm just going to have to take my chances and hope I don't cause a scare. If you hear about a suspicious device being detonated and a misguided nerd being hauled off to gitmo this weekend, it was nice knowing you all.
    Ya know, they read this board...

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    Only tangentially related: When I visited the US Space and Rocket
    Museum at Huntsville Alabama in 1993, they had a grey flight suit
    worn by either Keir Dullea or Gary Lockwood (I forget which, now)
    in '2001: A Space Odyssey'. It appeared to be greatly shrunken.
    Way too small for either actor to fit into. Way too small for even
    me to fit into. They also had the red space helmet Keir Dullea wore.
    No sign of shrinkage there, but it looked like it was carved out of
    wood! It may actually have been fiberglass, but looked like wood.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

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    Quote Originally Posted by grapes View Post
    Ya know, they read this board...
    Well, fortunately, they didn't even raise an eyebrow. They let me right through security with no problem. Scans are done and voila, the suit fits through the hatch perfectly.
    http://h.dropcanvas.com/03s0u/hatchsuit.jpg
    More to come when I have the time, I have more scans of the lunar module to add to densify the points and it's easier to see when I move it around in a video, but the bottom line is that the technique worked and the suit does fit through the hatch.

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    Quote Originally Posted by DaveC426913 View Post
    Wait! Before you go, there is one thing you absolutely must do!



    Will all your belongings to me.
    No such person has ever existed. Now, Please look at the bright light. Click image for larger version. 

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    Quote Originally Posted by NGCHunter View Post
    Well, fortunately, they didn't even raise an eyebrow. They let me right through security with no problem. Scans are done and voila, the suit fits through the hatch perfectly.
    http://h.dropcanvas.com/03s0u/hatchsuit.jpg
    More to come when I have the time, I have more scans of the lunar module to add to densify the points and it's easier to see when I move it around in a video, but the bottom line is that the technique worked and the suit does fit through the hatch.
    Wait. What is that?

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    Quote Originally Posted by grapes View Post
    Wait. What is that?
    The yellow dots are the space suit from 3D LIDAR scans that I did of Gene Cernan's practice suit sitting in the display case across from the LM.
    https://www.youtube.com/watch?v=t9ZSmcCmvr0
    I then imported that into a scan I did of the LM's hatch to show that it would fit through the hatch. It's easier to see in motion, so here's a crude gif animation until I can make a proper video about it:
    http://h.dropcanvas.com/9sgak/spacesuithatch3.gif
    I also combined multiple scans of the LM hatch in that animation to make it a bit more clear. The spacesuit fits through the hatch quite nicely. Because the LIDAR measures the position of each point it scans in real space, the two 3D models from the scans are automatically to scale with each other. The servo motor's coarseness results in some gaps between points, particularly on the LM since it's farther away from the scanner, but you can still see the much larger gap formed by the hatch and the suit fits it with a bit of room to spare (even with the point sizes inflated for both the suit and the LM to make it easier to see - each point measured by LIDAR becomes a cube occupying a set volume for visualization purposes).

  22. #22
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    I guess the HBs will just have to scrape the bottom of the barrel for another argument.

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    Wasn't the origin of this question the fact that astronaut figures in
    Revell Apollo spacecraft model kits were too big, not correct scale?

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

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    Quote Originally Posted by Jeff Root View Post
    Wasn't the origin of this question the fact that astronaut figures in
    Revell Apollo spacecraft model kits were too big, not correct scale?

    -- Jeff, in Minneapolis
    Heh, was it that? I honestly don't know the earliest origin, but the story I first heard was that the models of Neil and Buzz walking around outside the LM on display at the Smithsonian were made smaller than life size to try to hide the fact that the hatch was too small. As a secondary long term goal, I'd like to do a scan of them at the Smithsonian next time I'm in DC to compare them to the scan of Cernan's space suit. For all I know they could be sub-scale, the large main room the LM is sitting in certainly has a way of making things look small visually. I've also heard a similar story that the dummy sitting on the porch of the "under-construction" LTA-1 LM display at the Cradle of Aviation museum is deliberately smaller than a real person to try to hide some shenanigans about the hatch being too small.
    http://www.americanspacecraft.com/im...1/DCP_1880.JPG
    Of course, LTA-1 doesn't even have the final hatch design (not that the hoaxies notice this). Regardless, it's clear that the real hatch on the real last H mission LM-9 is large enough for a full scale space suit to fit through.

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    Quote Originally Posted by Jeff Root View Post
    Wasn't the origin of this question the fact that astronaut figures in
    Revell Apollo spacecraft model kits were too big, not correct scale?

    -- Jeff, in Minneapolis


    If our models are taken as exact representations of reality, then there is a vast conspiracy hiding the fact that real diesel and steam locomotives actually have a giant electric motor inside of them, and really get their power from 12V DC power supplied by the rails.

    Don't get me started on the real meaning of Hot Wheel cars.
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    That was very cool, NGCHunter. The GIF made it much easier to understand what I was looking at.

    I was going to say that it was too bad you had to waste your time disproving a silly hoax theory, but I can see where it provided a focus for your hobby.
    I may have many faults, but being wrong ain't one of them. - Jimmy Hoffa

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    Dang it! I don't have a PC (boot drive died) and my phone won't show your images and work blocks them! Curses!

    CJSF
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    If you were incorrect
    A fact is just a fantasy
    Unless it can be checked
    Make a test
    Test it out"
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    Quote Originally Posted by Swift View Post


    If our models are taken as exact representations of reality, then there is a vast conspiracy hiding the fact that real diesel and steam locomotives actually have a giant electric motor inside of them, and really get their power from 12V DC power supplied by the rails.

    Don't get me started on the real meaning of Hot Wheel cars.
    Back in the '60's, there was a big (but brief) controversy because Revell put out a cutaway model of the USS George Washington, the first Polaris missile submarine. Much clutching of pearls because they were giving away our secrets to the Ruskies. My parents got me the model. It didn't even have the correct number of missile tubes.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

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    Quote Originally Posted by NGCHunter View Post
    I'm also tentatively planning to use it to model the lunar rover they have on display to measure the angular size of the rover antenna as seen from the GCTA camera in order to measure the angular size of earth in a shot that had both in frame simultaneously, providing the data needed to refute the claim that earth wasn't large enough in the Apollo images of it (again an incredibly boneheaded mistake if it were true, yet it's frequently claimed).
    You don't need to go to such lengths. The angular size of the FOV is known. The angular size of the Earth is known. The pixel size of the picture against the pixel width of the Earth is pretty spot on in any full picture.

  30. #30
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    Quote Originally Posted by NGCHunter
    I'm also tentatively planning to use it to model the lunar rover they have on display to measure the angular size of the rover antenna as seen from the GCTA camera in order to measure the angular size of earth in a shot that had both in frame simultaneously, providing the data needed to refute the claim that earth wasn't large enough in the Apollo images of it (again an incredibly boneheaded mistake if it were true, yet it's frequently claimed).
    Let me guess. By taking 3D scans of the museum rover, you can evaluate perspective effects and thus calibrate your instrument to determine the distance from the camera to the rover in the mission photo, and thus calculate the angular size of its antenna. Am I correct? I can visualize how to do it in principle, with the challenge being to get the desired precision.

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