Spacesuits, also known as Extravehicular Mobility Units (EMUs), protect astronauts from the hostile and inhospitable conditions in space. They create an oxygenated and pressurized environment for the astronauts to breathe easily, and shield them from extreme temperatures that can range from -250°F to 250°F.
Did You Know?A spacesuit, without the astronaut in it, weighs approximately 280 pounds on Earth, while in the microgravity environment of space, a spacesuit weighs almost nothing.
The suit in itself consists of 14 layers of insulation to protect against extreme temperatures and other hazards. The inner layers provide cooling and ventilation, and are surrounded by a pressure garment layer. The outer layers are made from Gortex, Neoprene, Kevlar, and Dacron. These special materials prevent the suit from tears caused by micrometeoroids. All the materials are white because white reflects sunlight, and thus, prevents the suit from heating up.
The spacesuit consists of various other equipment designed to protect astronauts from radiation and other hazards in the uncongenial atmosphere. Go through this Buzzle article to know more.
Primary Life Support Subsystem
The backpack-like stuff seen on every astronaut's back is called the PLSS. As the name suggests, this backpack is vital for survival, since it provides oxygen for the astronauts to breathe. It also removes exhaled carbon dioxide, and contains a battery for electrical power.
The PLSS also holds a fan to circulate oxygen, water-cooling equipment, and a two-way radio. The PLSS also contains a warning system that lets astronauts know if something is wrong with the suit. The entire unit is covered with protective cloth layers. Contrary to popular belief, an astronaut's suit is not like a wetsuit that he/she enters into, but individual pieces of suits that are attached together to form an entire suit.
The top of the spacesuit includes the hard upper torso (HUT), the arm assembly, and the gloves.
Hard Upper Torso
The HUT is a vest made out of fiberglass that covers the chest and the back. It contains the Display and Control Module (DCM)―a unit that contains all the switches, valves, displays, and gages that are necessary to control the PLSS. The Primary Life Support Subsystem (PLSS) is attached to the HUT. A vital function of the HUT is that it serves as the connection for the tubes that allow oxygen flow and drain water.
As mentioned above, astronauts do not wear custom-made suits, but different parts assembled together. For the arms of the astronaut, different sizes of arms are available and sizing rings are used to make the arms longer or shorter.
In space, the fingers of an astronaut become the coldest part of their body. It is essential that the gloves provide protection as well as dexterity to work and pick up objects in space. Extravehicular Activity (EVA) gloves have heaters in the fingertips to beat the cold, and also provide protection and dexterity. A bearing connects the glove to the sleeve, which allows the wrist to turn.
Lower Torso Assembly
This section protects the lower half of the body and is made up of spacesuit pants and boots. A metal body-seal closure connects the lower torso to the hard upper torso, while the waist bearing helps the astronaut to move and turn.
A vital piece of equipment attached to the upper torso are the tethers. Tethers are cords that connect the astronaut to the spacecraft so that he/she does not float away in space while on a spacewalk. D-rings are used to attach tethers to the upper torso.
Some suits are plain white; some have red stripes; and others have candy cane stripes. These variations help to distinguish one astronaut from another.
The helmet has a pad that directs the oxygen which is maintained at the right pressure inside the helmet. It has a clear plastic bubble covered by the Extravehicular Visor Assembly. The visor is coated by a thin layer of gold to protect from the harmful rays of the Sun, utmost temperatures, and dust particles or small objects that may hit the astronaut while walking in space.
Communications Carrier Assembly
Another vital piece of equipment is the cap with earphones and microphones that is worn under the helmet, which connects to a radio on the spacesuit. This assembly helps astronauts communicate with each other and technicians and experts on Earth.
Simplified Aid for Extravehicular Activity Rescue, in short SAFER, is a life jacket which has small nitrogen thruster jets attached to it that come to the rescue of the astronaut if he drifts away from the space station. These jets can be controlled by switches located on the astronaut's arm.
Then, there are the boots that are designed to sustain wear and tear in space and also be light enough to enable astronauts to walk freely. Besides the parts mentioned above, there are many other pieces of equipment that comprise a spacesuit. These are multiple pockets all over the suit to accommodate various equipment like tools, penlight, scissors, etc., used by astronauts. An electrical connector to charge the batteries, urine collection device, in suit drink bag, etc.
Hence, in order to protect the astronauts from these threats, the spacesuits were created. These spacesuits have evolved over the decades after extensive research and experimentation to the present Extravehicular Mobility Unit (EMU) which helps astronauts cope up and face the stressful, unfriendly and inhospitable conditions in outer space.