Chemistry, art conservation, and space-age materials meet as conservators try to preserve the space suits worn by NASA astronauts.
When the command module, Columbia, from the successful Apollo 11 moon mission splashed down on July 24, 1969, each astronaut wore a custom-made space suit that had been designed specifically for working in the lunar environment. The bill of materials for each suit reads like an all-star list of 20th century chemical discoveries including: aluminized mylar, neoprene-coated nylon, dacron, urethane-coated nylon, tricot, nylon/spandex, stainless steel, and high strength composite materials.
Faced with the complex challenges of the lunar environment, space suit designers, ILC Industries, Inc, reached for the most advanced materials available. For example, polyvinylchloride tubing supported by spandex fabric was used in the cooling system to regulate the astronauts’ body temperatures. A combination of metal-woven fabric “Chromel-R” and silicone rubber gave the astronauts’ boots high temperature resistance and rugged protection from jagged rocks. Silicone rubber on the fingertips of gloves gave the astronauts a more authentic sense of touch and greater dexterity than if the gloves had been made of a single material. Neoprene-coated nylon pressure bladders helped provide flexibility in the joints of the suits so that the astronauts could walk, collect samples, sit in the lunar rover, or even hit a golf ball.
Forty years after the historic moon landing, the conservators of the Smithsonian’s National Air and Space Museum are developing new techniques such as CT scans to try to monitor and preserve the condition of the space suits. For example, sodium chloride from the astronauts’ sweat has caused corrosion of the aluminum-copper alloys in the wrist connections. PVC tubing used in the life support systems has been removed from the space suits since the phthalate plasticizer leaches out, discoloring the white exterior of the suits. Happily, the conservators have determined that storing the suits in a low humidity environment halts the degradation of all of the problematic materials so that these space suits, which allowed humans to walk on an airless moon, may be preserved to inspire future generations to explore the limits of science and our solar system.
Further information about the design of the Apollo and space shuttle space suits may be found at http://history.nasa.gov/spacesuits.pdf, and the challenges of conserving the suits is described at http://pubs.acs.org/isubscribe/journals/cen/89/i19/html/8919sci1.html