In order for an astronaut to talk to mission control, this part of the spacesuit must fit just like a cap. Astronauts become very thirsty while working in space. This part of their EMU holds water and has a straw so they can grab a quick drink. Though it looks silly, this part of the EMU is needed to keep the astronauts cool. It fits the astronaut like a new pair of pajamas.
Most astronauts have very hard heads.
Without this part of the EMU, though, their hair could be messed up by asteroids blowing by. Their favorite pair of shoes might not be along for the trip, but no need to worry. This part of the EMU protects an astronaut's feet from passing meteoroids. While wearing this piece of the EMU, every astronaut looks like Arnold Schwarzenegger. It's strong enough to support the life support system, the helmet, and the drink bag.