Following Gemini, the Apollo program added a new dimension in spacesuit design because actual spacewalks, on the surface of the Moon, were now to occur for the first time. As with Mercury and Gemini space garments, Apollo suits had to serve as a backup pressure system to the space capsule. Besides allowing flexibility in the shoulder and arm areas, they also had to permit movements of the legs and waist. Astronauts needed to be able to bend and stoop to pick up samples on the Moon. Suits had to function both in microgravity and in the one-sixth gravity of the Moon's surface. Furthermore, when walking on the Moon, Apollo astronauts needed the flexibility to roam freely without dragging a cumbersome combination oxygen line and tether. A self-contained portable life-support system was needed.
The Apollo spacesuit began with a garment that used water as a coolant. The garment, similar to long johns but laced with a network of thin walled plastic tubing, circulated cooling water around the astronaut to prevent overheating. A multi-layered pressure garment was worn on top of the cooling suit. The innermost layer of this garment was a comfort layer of lightweight nylon with fabric ventilation ducts. On top of this was a layer of neoprene-coated nylon surrounded by a nylon restraint layer. This layer contained the pressure inside the suit. Improved mobility was achieved by bellow-like joints of formed rubber with built-in restraint cables at the waist, elbows, shoulders, wrist, knees, and ankles. On top of the pressure layer were five layers of aluminized Mylar for heat protection, mixed with four spacing layers of non-woven Dacron.
Above these were two layers of material for additional thermal protection and a non-flammable layer of Teflon coated in a fibrous cloth. The outermost layer of the suit was white Teflon cloth. The last two layers were flame resistant. In total, the suit layers provided pressure, served as a protection against heat and cold, and protected the wearer against micrometeoroid impacts and the wear and tear of walking on the Moon.
Capping off the suit was a communications headset and a clear plastic pressure helmet. Slipped over the top of the helmet was an assembly consisting of sun-filtering visors and adjustable blinders for sunlight protection. The final items of the Apollo spacesuit were lunar protective boots, a portable life-support system, and custom-sized gloves with molded silicone-rubber fingertips that provided some degree of fingertip sensitivity in handling equipment.
The life-support system, a backpack unit, provided oxygen for breathing and pressurization, water for cooling, and radio communications for lunar surface excursions lasting up to eight hours. Furthermore, back inside the lunar lander the life-support system could be recharged with more oxygen and battery power for additional Moonwalks.
During the Apollo program, 12 astronauts spent a total of 161 hours of extravehicular activities on the Moon's surface. Additional extravehicular activities were spent in microgravity while the astronauts were in transit from the Moon to Earth. During a total of four hours, one astronaut, the command module pilot, left the capsule to retrieve photographic film. There was no need for the portable life-support system away from the Moon, as those astronauts were connected to the spacecraft by umbilical tether lines supplying them with oxygen.
5
Select the correct answer.
Why does the author most likely include the details in the first paragraph?
A.
to show the first time astrounats walked on the Moon
B.
to show that the Apollo program was very innovative
C.
to explain why there was a need for a new spacesuit design
D.
to explain how the new spacesuit was adapted