At the time, NASA was looking for what it called a Space Suit Assembly (SSA), something that could be worn during launch and reentry as well as outside the spacecraft. This worked out to be far more than just a suit. NASA wanted a Pressure Garment Assembly (PGA), a Portable Life Support System (PLSS), an Emergency Oxygen System (EOS) as well as whatever was needed to make it capable of supporting Extra-Vehicular Activity (EVA).

ILC’s proposal focused on refining existing technology with an eye on custom designs to suit mission needs. The company handed NASA a full pressure suit that was soft enough to be worn for days at a time yet durable enough to resist abrasion from Moon rocks. For ease of use, it came with detachable boots, gloves, and helmet, as well as a separate life-support backpack; the company boasted that even in a tight space, the suit could be donned by an astronaut without assistance in less than three minutes. NASA liked ILC’s suit but preferred a competitor, Hamilton Standard’s, version of the backpack. And so the space agency awarded a contract that split the work between the two companies.

Not long after beginning work on the suit in earnest, ILC engineers found the lunar spacesuit a bigger challenge than they had initially anticipated. Among the unexpected problems was keeping astronauts safe from themselves. A body at work generates a lot of heat, so ILC had to figure out how to dissipate the heat from inside the suit as well as the heat coming from outside. The solution was a unique set of space age long underwear called the Liquid Cooled Garment (LGC). The nylon-spandex knit formed the breathable structure while polyvinylchloride (PVC) tubes woven firmly into the fabric circulated water that absorbed the astronaut’s body heat. That heat then moved into the backpack where it could be dissipated.

The outer suit was more complicated, and after years of development and testing the A7L version emerged as the multi-layered, multi-pieced garment complete with a backpack assembly ready for its lunar mission.

The main piece was the Torso-Limb Suit Assembly, a single garment that covered everything save but the hands and head. With internal cables for stability and dipped rubber convoluted joints at the shoulders, elbows, wrists, hips, knees, and ankles, it was structurally rigid when pressurized but still gave the astronaut a good range of motion. Permanently attached to this main pressure garment was the Integrated Thermal/Meteoroid Garment (ITMG). Made from five layers of aluminized Mylar, one layer of polyester fiber fabric called Dacron scrim, and one layer of neoprene-coated nylon, all nested to protect against small impacts. The outermost layer was made of woven glass fibers, a material called Beta Cloth that would melt but not burn. For walking on the Moon, the outfit was completed with protective overboots, rubber-finger-tipped and abrasion-resistant gloves, and a set of sun filters worn over helmet faceplate. And, of course, the PLSS backpack.