A space blanket (also known as a

Mylar BoPET (biaxially-oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and a ...

blanket, emergency blanket, first aid blanket, safety blanket, thermal blanket, weather blanket, heat sheet, foil blanket, or shock blanket) is an especially low-weight, low-bulk

blanket A blanket is a swath of soft cloth large enough either to cover or to enfold most of the user's body and thick enough to keep the body warm by trapping radiant body heat that otherwise would be lost through convection. Etymology The term ...

made of heat-reflective, thin, plastic sheeting. They are used on the exterior surfaces of spacecraft for thermal control, as well as by people. Their design reduces the heat loss in a person's body, which would otherwise occur due to thermal radiation, water evaporation, or convection. Their low weight and compact size before unfurling make them ideal when space or weight are at a premium. They may be included in

first aid kit A first aid kit or medical kit is a collection of supplies and equipment used to give immediate medical treatment, primarily to treat injuries and other mild or moderate medical conditions. There is a wide variation in the contents of first aid ...

s and with camping equipment. Lost campers and hikers have an additional possible benefit: the shiny surface flashes in the sun, allowing its use as an improvised distress beacon for searchers and as a method of signalling over long distances to other people.

Manufacturing

First developed by

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeedin ...

Marshall Space Flight Center The George C. Marshall Space Flight Center (MSFC), located in Redstone Arsenal, Alabama (Huntsville postal address), is the U.S. government's civilian rocketry and spacecraft propulsion research center. As the largest NASA center, MSFC's firs ...

in 1964 for the US space program, the material comprises a thin sheet of

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adapta ...

(often PET film) that is coated with a

metal A metal (from ancient Greek, Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, e ...

lic, reflecting agent, making it

metallized polyethylene terephthalate Metallised films (or metallized films) are polymer films coated with a thin layer of metal, usually aluminium. They offer the glossy metallic appearance of an aluminium foil at a reduced weight and cost. Metallised films are widely used for decorat ...

(MPET) that is usually gold or silver in color, which reflects up to 97% of radiated heat. For use in space,

polyimide Polyimide (sometimes abbreviated PI) is a polymer containing imide groups belonging to the class of high-performance plastics. With their high heat-resistance, polyimides enjoy diverse applications in roles demanding rugged organic materials, e. ...

(e.g.

Kapton Structure of poly-oxydiphenylene-pyromellitimide Kapton insulating pads for mounting electronic parts on a heat sink Kapton is a polyimide film used in flexible printed circuits ( flexible electronics) and space blankets, which are used on spa ...

, UPILEX) substrate is usually chosen due to its resistance to the hostile space environment, large temperature range (cryogenic to −260 °C and for short excursions over 480 °C), low

outgassing Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen, or absorbed in some material. Outgassing can include sublimation and evaporation (which ...

(making it suitable for vacuum use), and resistance to

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...

radiation. Aluminized

, with foil thickness of 50 and 125 µm, was used on the

Apollo Lunar Module The Apollo Lunar Module (LM ), originally designated the Lunar Excursion Module (LEM), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed ...

. The polyimide gives the foils their distinctive amber-gold color. Space blankets are made by vacuum-depositing a very precise amount of pure

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...

vapor onto a very thin, durable film substrate. Infrared spectroscopy

Usage

In their principal usage, space blankets are included in many emergency,

first aid First aid is the first and immediate assistance given to any person with either a minor or serious illness or injury, with care provided to preserve life, prevent the condition from worsening, or to promote recovery. It includes initial i ...

, and survival kits because they are usually waterproof and windproof. That, along with their low weight and ability to pack into a small space, has made them popular among outdoor enthusiasts and emergency workers. Space blankets are often given to

marathon The marathon is a long-distance foot race with a distance of , usually run as a road race, but the distance can be covered on trail routes. The marathon can be completed by running or with a run/walk strategy. There are also wheelchair div ...

ers and other endurance athletes at the end of races, or while waiting before races if the weather is chilly. The material may be used in conjunction with conductive insulation material and may be formed into a bag for use as a

bivouac sack A bivouac shelter is any of a variety of improvised camp site, or shelter that is usually of a temporary nature, used especially by soldiers, or people engaged in backpacking (hiking), backpacking, bikepacking, scouting, or Mountaineering, mount ...

(

survival bag A survival kit is a package of basic tools and supplies prepared as an aid to survival in an emergency. Civil and military aircraft, lifeboats, and spacecraft are equipped with survival kits. Survival kits, in a variety of sizes, contain s ...

). In

, the blankets are used to prevent or counter

hypothermia Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe ...

. A threefold action facilitates this: * The airtight foil reduces

convection Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the c ...

* Heat loss caused by

evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when h ...

perspiration Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distr ...

is reduced * The

reflective Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The ' ...

surface inhibits losses caused by

thermal radiation Thermal radiation is electromagnetic radiation generated by the thermal motion of particles in matter. Thermal radiation is generated when heat from the movement of charges in the material (electrons and protons in common forms of matter) i ...

In a hot environment, they can be used to provide shade or protection against radiated heat, but using them to wrap a person would be counterproductive, because

body heat Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperatur ...

would get trapped by the airtight foil. This effect would exceed any benefit gained from heat reflection to the outside. Wearing a space blanket produces an insignificantly slower cooling rate after running in hot, humid conditions. Space blankets are used to reduce heat loss from a person's body, but as they are constructed of PET film, they can be used for other applications for which this material is useful, such as insulating containers (e.g. DIY solar concentrators) and other applications. In addition to the space blanket, the

United States military The United States Armed Forces are the military forces of the United States. The armed forces consists of six service branches: the Army, Marine Corps, Navy, Air Force, Space Force, and Coast Guard. The president of the United States is ...

also uses a similar blanket called the "casualty blanket". It uses a thermal reflective layer similar to the space blanket, backed by an

olive drab Olive is a dark yellowish-green color, like that of unripe or green olives. As a color word in the English language, it appears in late Middle English. Shaded toward gray, it becomes olive drab. Variations Olivine Olivine is the typic ...

-colored, reinforcing, outer layer. It provides greater durability and warmth than a basic space blanket at the cost of greater bulk and weight. It is also used as a partial liner inside the layers of bivouac sacks in very cold weather climates. Space blankets were also used by the

Taliban The Taliban (; ps, طالبان, ṭālibān, lit=students or 'seekers'), which also refers to itself by its state (polity), state name, the Islamic Emirate of Afghanistan, is a Deobandi Islamic fundamentalism, Islamic fundamentalist, m ...

to hide their heat signature from NATO forces.Smucker, Philip
"U.S. soldiers' options limited to protect Afghans from Taliban."
The State. Jun. 2, 2009.

References

External links

* {{DEFAULTSORT:space blanket Blankets First aid Materials Technical fabrics NASA spin-off technologies American inventions 1964 introductions

Manufacturing

Usage

See also

References

External links