The Mylar space blanket was developed by NASA to reduce heat loss for spacecrafts as well as humans.
The material is a thin sheet of plastic that’s been coated with an atomically thin metallic layer. The result is an extremely lightweight blanket that is capable of reflecting up to 97% of radiated heat.
This material is commonly used on the exterior surfaces of spacecraft for thermal control. It was used by NASA to create the first passive communications satellite, a 131 ft (40 m) balloon called Echo II, and the Kapton space blanket gave the Apollo Lunar Module its distinctive gold color.
Their small size makes space blankets perfect to toss in camping packs or emergency kit. Plus, they can be used to reflect the sun as a distress signal.
Keep away from infants. Do not cover anyone’s face with the blanket as this can result in suffocation.