In a November 1949 symposium, Harry Ross presented a paper on the “Lunar Space-Suit”. Ross ha
d examined the problem of a 68 kg lunar space suit (equivalent to 11 kg on the Moon) which could be worn for up to 12 hours, within the temperature range of 120 degrees to minus 150 degrees Celsius, representing night and day. The suit design was a 4-ply, made up of a thin exterior skin of closely woven cloth. It had a 1 cm layer of cellular heat-resisting material (Kapok, wool, felt et cetera) and a 1-2 mm main airtight sheath of fabric-backed natural or synthetic rubber. It also had an interior lining of non-hygroscopic material, mainly for comfort and to manage contact between the rubber and skin and absorption of the water-vapour. The exterior of the lunar space suit was to be a highly burnished metallic film, designed to reflect as much heat as possible. The chest and thigh areas were to be given an external matt-black finish to permit radiation manage heat loss. Operation of the suit during the lunar day would require further cooling through the use of a low boiling liquid such as Ammonia or water – which would vaporise to space through a thermostatic valve. The helmet was to be a light, rigid double-shell structure, with the inner a bright alloy metal and the outer a plastic with burnished metal coating. Lateral vision of 180 degrees was proposed with a minimal vertical extension in order to minimise heat gain or loss. A special glass to prevent heat and actinic Ultra-Violet rays would be employed. There would be further precautions, including providing the helmet with a shading peak and an external movable visor made either of darkened glass or bright metal pierced with cross-slits in front of the eyes. The suit was to be a good fit to ensure maximum comfort and the shoulders would be internally padded. Considerable thought went into the problem of air-conditioning, as discussed by Bob Parkinson in his book “Interplanetary”:
“Compressed (bottled) oxygen was regarded as simplest, and Ross recognised that a skin-tight suit with bottled oxygen flushing to waste might be sufficient, the weight of even a 12-hr supply not being excessive. However, a pure liquid oxygen supply was suggested, with the atmosphere maintained at about 160 mm Hg (21 kPa). The suit’s atmosphere was to be circulated through the conditioning units and throughout the dress by an electric fan-pump driven by the electric battery. Respired carbon dioxide was to be removed by chemical means – sodium peroxide being preferred because the reaction yielded oxygen, reducing the generous allowance of 0.78 litres per min by as much as 43% – as against, for example, sodium hydroxide, where there is no regain. The sodium peroxide would also absorb water, of which it was assumed the lungs and skin would yield some 108 gm/hr”.
The space suits that were eventually worn by the Project Apollo astronauts are a far cry from this original 1940s design. But the work started out by Harry Ross, led to credible thinking on how humans could survive in a self-contained, mobile habitat.