5
$\begingroup$

In the image shown in the question Why is the Apollo LM landing gear covered with so much thermal isolation? (also shown below) it appears that the color of the film around the bottoms of the lander's legs is close to "gold color" (though not necessarily related to the metal of the same name) whereas the film on most of the body looks to be a darker red color.

There is also a shiny "metallic" color film and a charcoal gray film as well.

I know there are materials like metallized Kapton and Mylar but I don't know what is used in this case and if there are different thicknesses of the film involved.

  1. How many different kinds of insulation film are wrapped around the Apollo Lunar Module?
  2. Are the different colorations I'm seeing real? If so, why? Different films or just optics?

Apollo lunar module Image AS11-40-5915.jpg

Image AS11-40-5915.jpg from Apollo 11 Lunar Surface Journal, from this question.

$\endgroup$
3
$\begingroup$

Only a partial answer about the medium gray foils.enter image description here

The thermal blanket consists of multiple-layered (at least 25 layers) of aluminized sheet (mylar or H-film). Each layer is only 0.00015 inch thick and is coated on one side with a microinch thickness of aluminum. To make an even more effective insulation, the polymide sheets are hand crinkled before blanket fabrication. This crinkling provides a path for venting, and minimizes contact conductance between the layers. Structures with a high thermal conductivity, such as antenna supports and landing gear members, that pass through the thermal blanket also have thermal protection. Individual blanket layers are overlapped and sealed with a continuous strip of H-film tape.

Mylar sheets are used predominantly in those areas where temperatures do not exceed 300° F. In areas where higher temperatures are sustained, additional layers of H-film are added to the mylar sheets. H-film can withstand temperatures up to 1000° F, but, because it is a heavier material, it is used only where absolutely necessary. Certain areas of the ascent stage are subjected to temperatures as high as 1800° F due to CSM and LM RCS plume impingement. These areas are thermally controlled by a sandwich material of thin nickel foil (0.0005 inch) interleaved with lnconel wire mesh and lnconel sheet.

Block quotes and image from: APOLLO NEWS REFERENCE LUNAR MODULE QUICK REFERENCE DATA

$\endgroup$
  • 1
    $\begingroup$ Does anybody understand the difference between aluminized polyimide (H-film) and aluminized polyimide (Mylar)? Two different manufacturers of polyimide foils? $\endgroup$ – Uwe Aug 2 at 14:36
  • $\begingroup$ wow, that's complicated stuff! $\endgroup$ – uhoh Aug 2 at 14:55
  • 2
    $\begingroup$ @uwe As far as I can tell that's a mistake/oversimplification. H-film is now called Kapton and is a polyimide, however Mylar isn't (strictly speaking). Interestingly both are made by dupont (Mylar and Kapton, its possible h-film was another companies trade-name). Roughly: Mylar is strong reflective and tough. Kapton has (as pointed out) very good resistance to high temperatures. I also is very good at dealing with low temperatures too. $\endgroup$ – ANone Aug 2 at 15:05
  • $\begingroup$ This is not the first time where I have seen NASA Apollo press kits mistakenly call Mylar and Kapton the same thing; they are not. (Specific example: the CM thermal protective system.) If you read the Apollo Experience Reports or the Operations Handbooks (which are documents for a technical audience), the difference is correctly distinguished. $\endgroup$ – DrSheldon Aug 2 at 19:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.