A space blanket (also known as a Mylar blanket, first aid blanket, safety blanket, thermal blanket or weather blanket) is an especially low-weight, low-bulk blanket made of heat-reflective thin plastic sheeting. Their design reduces the heat loss in a person’s body which would otherwise occur due to thermal radiation, water evaporation, or convection.
Their compact size before unfurling and light weight makes them ideal when space is at a premium. They may be included in first aid kits and also in camping equipment. Lost campers and hikers have an additional possible benefit: the metallic surface appearance flashes in the sun, allowing use as an improvised distr-beacon for searchers.
Outer space can be very cold or very hot — or both. Solar radiation is intense, but objects in the dark lose heat quickly. The temperature can vary by 275 degrees Fahrenheit (135 degrees Celsius) from one side of an object to the other [source: NASA Temperature]. As a result, scientists at the National Aeronautics and Space Administration (NASA) have had to come up with ways to warm, cool and insulate people and equipment.
The space blanket is probably the best-known NASA spinoff for keeping you warm. It was originally designed to protect against temperatures extremes in space and used on almost all manned and unmanned NASA missions.
To create the material that goes into a space blanket, NASA researchers deposited vaporized aluminum onto plastic. The result was a very thin but durable sheet of material that was very good at reflecting the infrared waves that created heat. The material could either reflect and preserve body heat or ward off the intense radiation of the sun [source: NASA Scientific Reflecting].
Space blankets were used as insulation in the suits that astronauts wore when walking on the moon. They also serve as a radiation barrier for instruments, protecting them from extreme temperatures. On earth, space blankets are available to hikers who need to preserve body heat. Spectators watching a football game in January also use them to keep warm in the stands.
An important use of space blankets is in medical emergencies like auto accidents. They are a light, convenient way to keep a victim from losing heat and suffering the effects of a low body temperature.