8
$\begingroup$

The Apollo LM landing gear – struts, footpads, shock absorbers and contact probes was completely covered with foils.

enter image description here

There should be no temperature sensistive electronics within the landing gear, only switches and cables for the contact probes.

So what should be protected against extreme temperatures?

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

Improve this question
$\endgroup$
5
  • $\begingroup$ Has it just been my imagination all these years, or are there two slightly different color films? $\endgroup$
    – uhoh
    Commented Aug 2, 2019 at 10:31
  • 1
    $\begingroup$ @uhoh I see four different foil types. It may be another question. $\endgroup$
    – Uwe
    Commented Aug 2, 2019 at 10:45
  • 1
    $\begingroup$ speculation: without insulation, the legs would act as radiators, cooling down or heating the descent stage. $\endgroup$
    – Hobbes
    Commented Aug 2, 2019 at 10:51
  • $\begingroup$ @Uwe How many different kinds of insulation film are wrapped around the Apollo Lunar Module? $\endgroup$
    – uhoh
    Commented Aug 2, 2019 at 10:52
  • 6
    $\begingroup$ @Hobbes I think it's to protect the lunar surface; if it gets too warm the cheese will melt and flow... $\endgroup$
    – uhoh
    Commented Aug 2, 2019 at 10:53

1 Answer 1

Reset to default
15
$\begingroup$

Everything of the Lunar Module should be as light as possible. Therefore no thick-walled, heavyweight, pneudraulic-type struts were used to absorp the landing shock but lightweight aluminum honeycomb cartridges. Shock was absorbed by crushing the honeycomb cartridges.

enter image description here

The footpads were build as a sandwich structure of a honeycomb core between two aluminum panels.

The aluminum honeycombs were assembled using adhesives, also the footpads. The used aerospace aluminum alloys and the adhesives should not be too hot or too cold, they would loose their strength otherwise.

Landing-gear thermal insulation must maintain the landing-gear temperatures at or below design levels to ensure positive structural margins of safety and proper me­chanical operation during deployment and landing. Furthermore, temperature control of the honeycomb energy absorbers within specified limits is necessary to preclude large variations in crush-load levels.

enter image description here

From: APOLLO LUNAR MODULE LANDING GEAR pdf

According to this pdf, long term temperature of most honeycombs should be lower than 350 °F or about 175 °C.

About 300 °F or 149 °C may reduce strength to about 80 %.

Improve this answer
$\endgroup$
4
  • 1
    $\begingroup$ Interesting. Do you have a source in re: adhesives? $\endgroup$
    – Stu Smith
    Commented Aug 4, 2019 at 5:07
  • 1
    $\begingroup$ @StuSmith see these pages: 1 2 3. $\endgroup$
    – Uwe
    Commented Aug 5, 2019 at 8:39
  • $\begingroup$ Very good, thanks! $\endgroup$
    – Stu Smith
    Commented Aug 5, 2019 at 14:24
  • 1
    $\begingroup$ I notice the quoted text refers to "positive structural margins of safety and proper me­chanical operation", which I take to include both structural failure to due to either excessively high or low temperature, but also mechanical issues such as binding of the moving parts due to differential expansion/contraction. $\endgroup$
    – Anthony X
    Commented Aug 6, 2019 at 0:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

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