The Extravehicular Mobility Unit (EMU) has many parts, all made in different sizes to fit a wide range of astronauts. “Extravehicular” means “outside of the vehicle” — or, in the case of today's astronauts, outside the International Space Station. This suit is basically a personal spacecraft designed to protect an astronaut from the dangers of Space.
Read on for more information on the helmet assembly, and to find out what astronauts do for snacks during a seven- or eight-hour spacewalk!
The helmet covers and protects an astronaut’s head, and has a Vent Pad that sends oxygen to the front of the helmet. This ensures that the astronaut can breathe, and that the helmet is properly pressurized. The bubble is covered by the Extravehicular Visor Assembly, which is coated with a thin layer of gold to filter harmful rays from the Sun. The visor also protects the astronaut from very small flying objects. In Space, even a tiny piece of dust can be dangerous!
Recording equipment such as a camera and lights can be attached to either side of the helmet, in order to record and broadcast elements of a spacewalk from the astronaut’s perspective.
The Communications Carrier Assembly is nicknamed a “Snoopy Cap” because it is black and white, like the Peanuts comic-strip character of the same name. The nickname dates back to the Apollo space program of the 1960s, which is also when Peanuts was extremely popular.
The cap is worn under the helmet, and contains earphones and a microphone connected to the suit’s radio.
In-Suit Drink Bag
The In-Suit Drink Bag (IDB) is a plastic, water-filled pouch which is operated by a tube-and-valve system. The astronaut bites down on the valve to open it and make the water flow, then closes the valve by releasing his or her bite.
A fruit bar used to be fitted inside the suit, close to the astronaut’s mouth. This is no longer done, because most astronauts prefer to eat first and not snack during a spacewalk — even though they are sometimes working for eight hours!