posted 09-30-2012 02:20 AM               

• the thickness of the floor where the astronauts were in flight position (before their dashboard);
  
• the thickness of the side walls

posted 09-30-2012 02:46 PM               

On my first visit to the Smithsonian in Washington in 1993, I was shocked at how thin the walls of the LM on display there at the time actually were. It's one of my abiding memories of that visit.

posted 09-30-2012 03:11 PM               

The single wall concept consisted of 1/8" aluminum or equivalent mass.

posted 09-30-2012 03:47 PM               

OK, looking at that again I saw where the cross section on that same page has the outer skin at 0.012 minimum which would make sence for 5 psi and add credibility to the oh-so-thin skin stories.

I believe the 1/8 reference may be the single skin thickness equivalent for the multi layer cross section shown on the same page.

posted 09-30-2012 06:15 PM               

The cabin floor was 2" thick honeycomb.

posted 09-30-2012 06:46 PM               

Crew Compartment

The crew compartment was cylindrical in section in a welded and riveted construction, 92 inches in diameter and 42 inches deep, giving a habitable volume of 160 cubic feet, just sufficient for the two crewmembers to stand side by side. Due to the weight saving programs the compartment skin was reduced to a thickness of 0.012 inches, the equivalent of approximately three layers of kitchen foil.

posted 10-01-2012 01:26 PM               

quote:

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Originally posted by space1:
I mentioned that the pressurized cabin web thickness was specified as thin as "0.015 to 0.025" inches thick.

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posted 10-03-2012 06:46 AM               

According to this ALCOA source, US aluminum beverage can walls were approximately 0.015 inches thick in the 1970s. According to this excellent Scientific American article from September 1994, The Aluminum Beverage Can, can wall thicknesses were reduced even further to 0.003-0.006 inches. This study shows that US aluminum soda cans with walls 0.005 inches thin can contain internal gas/liquid pressure loads of 50+ psi.

Moving away from aluminum pressure vessels, I wanted to check relevant dimensions of aluminum sheet and foil. According to this Aluminum Industry document, aluminum sheet is a product 0.008-0.249 inches thick (previously 0.006-0.249 inches), and aluminum foil is a product 0.0079 inches or less thick (previously less than 0.006 inches). Reynolds Wrap Aluminum Kitchen Foil varies in thickness from 0.00064-0.00137 inches as you progress from the standard product to the extra heavy product. So while the aluminum skin of the Apollo LM crew cabin may have been, in certain areas, the equivalent of 3 (very thick) layers of aluminum foil, that foil was not thin modern-day kitchen foil grade. Perhaps kitchen foil of the 1960s-1970s was an awful lot thicker!

Overall, the chem-milled aluminum skin was sufficiently robust for the lunar landing missions. While you may not have been able to push your finger through the side walls, a sharp pointed object or a stray foot may have resulted in disaster so care was needed. Andrew Chaikin wrote in A Man On The Moon (p156):

"In the ascent stage, the walls of the crew cabin were thinned down until they were nothing more than a taut aluminum balloon, in some places only five-thousandths of an inch thick. Once, a workman accidentally dropped a screwdriver inside the cabin and it went through the floor."