Apollo 16 Lunar Module Foil

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    A 8x8” book of Kapton foil, Velcro, tape and some unusual rectangular orange patches (detail of that below). Apollo 16 with LM Orion launched 40 years ago, on April 16.

    You probably remember the lunar modules, wrapped in bright gold like a present to the cosmos. I always thought that there was one layer of foil to reflect the harsh sunlight in space.

    I was surprised to see that this blanket from the Apollo 16 LM was made of 26 layers, of different colors and thicknesses.

    As I recently learned, the foil was also a thermal blanket, not just a reflector. Earlier this month, EDN Magazine interviewed Grumman’s Ross Bracco, one of 25 engineers who began development of the LEM, as it was first called:

    “Still another major challenge Bracco and his team faced was the fact that the LEM was expected to land on the sunny side of the lunar surface, which meant an environmental temperature of 250°F and a shade temperature of -250°F. A low-cost technique was needed to insulate and protect the LEM's structural materials, including the landing feet. The team decided to use 12 to 18 layers of Kapton or aluminized Mylar material sandwiched together in a 70°F earth clean room and trap the air with a special sealing tape. This trapped air remained permanently at 70°F and was used in many areas of the LEM, including the cupped landing feet. The ‘foil’ around much of the LEM was made with 2- and 5-mil aluminized Kapton film.”

    scleroplex, origamidon, solerena, and 9 other people added this photo to their favorites.

    1. jurvetson 25 months ago | reply

      Top view, with Velcro band:

      Anyone have an idea what the orange rectangular patches are for? Or how temperature was kept at 70°F?

      Flip side:

      Removal tag:

      LM-11 is the Lunar Module used on Apollo 16, named Orion by the crew.

      Kennedy Space Center QC tag:

      And here's Orion on the moon, with a link to a better action shot =)

    2. scleroplex 25 months ago | reply

      so much work!

    3. solerena 25 months ago | reply

      your first shot is so cool, like some sort of sci-fi...

    4. pegleg000 25 months ago | reply

      I _think_ that the orange patch is Kapton tape used to repair tears in the Kapton or Mylar, or possibly to provide a venting path between layers. The Kapton/Mylar allows very little conduction and the aluminization prevents radiation between layers. Simplistically, the multi-layer blankets act in a manner similar to a thermos bottle, to keep the interior at a constant temperature, by preventing thermal radiation and conduction from the inside to the outside. Usually, there is a layer of low conductivity mesh material between layers to keep them separated. I'm not sure that the blankets used on LEM were unvented as implied by the EDN article. Trapped air would cause the blankets to at least puff out in the vacuum of space, if not blow out. The blankets I'm familiar with, on later spacecraft, were all vented, again with a nylon/dacron/ etc mesh between layers. But it's been a long time since I had hands-on experience with this stuff - I've forgotten more than I knew......

    5. jurvetson 25 months ago | reply

      very cool. Please jog that memory! Maybe this will help. Just in from spaceaholic:

      Screen Shot 2012-03-22 at 10.11.00 PM
      Screen Shot 2012-03-22 at 10.12.03 PM

      from Lunar Module Structures Handout LM-5, In support of LM-5 Structures Course, MSC Houston, May 1969.

      Whoa. That thermal blanket diagram has 26 layers. Maybe I counted correctly after all. =)

      I always wondered why the foil was only on the bottom. The Descent Stage was unpressurized and had no bulkhead walls. The lightweight Kapton blanket was all she had.

    6. pegleg000 25 months ago | reply

      Here's a couple of links on thermal blanket design. The spacecraft thermal control is one of the more difficult tasks in the overall design. Maintaining structures and electronics (and humans!) at benign temps in the space environments is extremely complex. Direct exposure to sunlight, deep space (-270 C or so), eclipses, reflections, varying payload power dissipation, etc, and with the thermal properties degrading over time, all need to be modeled. While always trying to minimize thermal control weight and heater power loads.....


    7. ukweli 25 months ago | reply

      "This trapped air remained permanently at 70°F"


    8. jurvetson 25 months ago | reply

      Yea - I had the same reaction. Meanwhile, here are some answers to my question from spaceaholic:

      The LM was the first true manned spacecraft - no atmospheric dynamic loads to contend with..also beneficial for tank venting (cyro boil-off). The LM always oriented on the lunar surface so that the sun was radiating against the aft equipment bay, and that area did incur structural deformation as a result. The waste heat was rejected via sublimaters ontop of the LM)

      Here is the ascent stage of Orion, after a three-day tanning session on the moon, showing pretty significant damage to the Inconel panels covering the bay:

      Apollo 16 Orion Ascent Stage

      And sticking out like orange shirttails, you can see kapton employed inside the ascent stage aft equipment bay panels.

      Apollo 16 Orion Ascent Stage

    9. Happy Tinfoil Cat 25 months ago | reply

      The more stuff like this I see, the more amazed that these guys made it back alive. A person could say that there is only one atmosphere difference between Earth and space, but considerations like these show how difficult it was... over 40 years ago.

    10. Astrocatou 25 months ago | reply

      Its the spacesuit (EVA) heating/cooling control that must be fascinatingly complex...

    11. tuckerproject 9 months ago | reply

      Can you say were you located this specific picture? Larger sizes, like this, can't be found anywhere else...

    12. jurvetson 9 months ago | reply

      I took the photo, and it's an artifact in my space collection. Did you mean large sizes of foil like this (or large sizes of this particular photo?)

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