Model A7LB Extravehicular Mobility Unit—1971 The Apollo model A7LB was the ultimate moonwalking suit. This Extravehicular Mobility Unit (EMU) allowed a crewman to work on the moon for up to seven hours. The suit’s red stripes identified the mission commander. This one represents the one worn by US Air Force Col David Scott in July 1971 on Apollo 15, the only moon landing mission with an all-Air Force crew. The A7LB was more flexible than earlier suits and had a spiral entry zipper around the waist and back instead of straight down the back as in earlier suits. The 212-lb EMU (35 lbs in the moon’s 1/6 gravity) let astronauts move about easily, touch the ground, and drive the lunar rover. The backpack, built by Hamilton Standard, carried oxygen and pumped cooling water through a network of small tubes sewn into astronauts’ undergarments. It also contained emergency oxygen, batteries, and a radio with an antenna. The outer helmet assembly was a series of coated visors, shades, and insulation that fit over a clear bubble helmet. Like other Apollo suits, this one had a very complex inner system of joints, pulleys, cables, and a pressure bladder. The version shown here had 22 thin layers of insulation and pressure-retaining materials that slid easily over one another like bags within bags. The suit’s blue fittings were oxygen, water, and electrical connections; the red fittings were gas outlets. The box on the chest controlled the backpack. The gloves and boots featured woven stainless steel fabric, and the boots had silicone rubber soles. This suit is a reproduction and is on display in the museum's fourth building. (Video) Space Suits Lecture from museum historian Dr. Doug Lantry Click here to return to the Space Gallery.