A Helmet is part of the EVA Suit of an astronaut which is designed to protect the wearer from numerous environmental hazards especially the hard vacuum of outer space. The helmet of an EVA suit also has a clear faceplate to allow the wearer to see while still maintaining a safe and comfortable environment for them. Although in reality the helmets do not actually form a seal around the astronaut, in the Beta reality they are airtight.
The current helmets are composed primarily of papier-mâché with a plexiglass faceplate, and they are white and blue. Since wearing a helmet for a long period of time can make an astronaut overheat, miniature fans have been installed on the inside, internally powered by a 9-volt battery.
Helmets are necessary for EVAs and IVAs. It is worth noting that although sound does not travel through the vaccuum of space, astronauts on EVA can place their helmets together and hear one another through the vibrations in the helmet.