SPACE BLANKET, FROM NASA TO YOUR KIT
Space blankets, also known as emergency blankets or Mylar blankets, were first developed in 1964 by NASA for the US space program. The agency used an extraordinarily strong polyester film developed by DuPont in the early 1950s and called it Mylar.
In the mid-1970s, space blankets started being distributed to marathon race finishers to stabilize their body temperatures. They were also used in medical facilities to keep patients warm. Nowadays, space blankets have become a must-have item for first aid and survival kits. The technology has been incorporated in outdoor clothing and sleeping bags as well.
How can something so thin keep you warm?
The material is made of a very thin sheet of plastic (usually ethylene polyterephthalate, or PET) with a metallic coating on both sides that is able to reflect up to 80% of radiated heat. When radiant heat hits the shiny surface it basically bounces off.
Space blankets are waterproof and can prevent heat loss from evaporation when you are sweating. If it's close to your skin your sweat won't be able to evaporate. Remember that, over time, this will create moisture inside the blanket and might soak into your clothes.
The blankets are also windproof, and prevent heat loss from convection, when your body heat is carried away by the wind.
PET material has a low thermal conductivity, so you can place it between your body and the ground if you are seated or lying down, to avoid body heat loss by conduction.
How to properly use a space blanket?
A space blanket generally costs around $3 or $4, comes in packaging smaller than a deck of cards and weighs less than 3 ounces (85 grams). Unfolded it’s about 56 by 84 inches (142 by 213 centimeters).
To keep yourself warm, wrap it over dry clothes with the shiny surface inside. Since it stops evaporation, make sure you vent it just enough to avoid vapor build-up inside the blanket. Otherwise, your clothes may become wet and you will be colder (wet clothing increases heat loss by a factor of 5).
You also use it to keep your space warm, for example, in your car if you are trapped in cold weather. Cover the windows with the space blanket shiny side in and it will help reflect any source of heat, including your body, back inside the car. (Don’t try this while driving, obviously).
To upgrade your emergency shelter and protect you from the rain and snow, place it in front of a heat source, like a campfire, to reflect heat back to you. (Avoid contact between the blanket and any open flamme).
For lining clothes and shoes, cut pieces of the space blanket to put inside your shoes or under your coat (but not next to the skin). Be careful to avoid excessive sweating.To keep yourself cool a double side space blanket can also reflect heat away from you. Place the shiny side of the blanket outward to protect against the sun heat. Same thing for your shelter or your car.
As a first-aid item If someone is going into shock, wrap them with the blanket. Shock is a critical condition brought on by the sudden drop in blood flow through the body (it may result from trauma, heatstroke, blood loss, an allergic reaction, severe infection, or other causes).
As a signal for help the shiny surface of the blanket is very visible from the sky when oriented to the rescuers or when using the reflectionion of your flashlight at night.
Use wisely and with caution
Like every item you have in your emergency kit, learn how to use the emergency blanket before you really need it.
Even if most space blankets conform to the Flammable Fabrics Act, keep them away from open flame, as they will burn if ignited.
You should cover your head with a wool hat since this is where most radiant heat is lost but never cover your face with a space blanket to avoid suffocation risk.
Don’t put a space blanket right next to your skin.
Space blankets are pretty durable and also very thin, beware of rips, especially if you use it as a shelter. Add a piece of duct tape on the corners before attaching them.
When you wrap the blanket around your body, add an extra source of heat inside, like a hand warmer, warm water in a sealed container (to avoid vapor), a heated rock. This is especially helpful if you are already hypothermic, since your body won’t have enough heat to be reflected by the blanket.
How to select your space blanket
You can find several different types of space blankets for sale in outdoor and sporting goods stores.Price - Super cheap space blankets will do the job, but you should consider them disposable, as they won’t last more than one or two uses.
Size - They are usually big enough to cover one person but you can find some larger ones that will fit two.
Shape - Space blankets can be sold with a poncho cut that allows you to wear it easily over your clothes but will restrict the number of different uses. You can also buy a bivy sack (short for bivouac sack), which is basically a single-person, waterproof shelter shaped like a sleeping bag. It is a bit heavier than a regular space blanket, but it is also much more durable.Thickness - The thicker blankets are more durable and some of them come with grommets which make them easier to use as a shelter.Color - The heat reflective side of a space blanket is always shiny. The other side can be any color but we recommend choosing a bright colour (orange or red) to make it more visible, specifically for rescue situations. A FEW OF OUR FAVORITE SPACE BLANKET TO CONSIDER
Basic space blanket
Wanpion Emergency Mylar Thermal Blankets
Survival Foil Space Blanket, Pack of 5
Color: orange
Weight: 1.76 Ounces
Dimensions: 52 x 82 in
2 person space blanket
S.O.L. Survive Outdoors
Color: orange
Weight: 3.2 Ounces
Dimensions: 58 x 98 in, Sized to fit two people.
Bivy bag
SOL Emergency Bivy XL
Bright orange exterior is easy to spot, even in bad weather
Dimensions: 84 x 60 in. sized to shelter up to 2 adults
Weight: 5.8 Ounces
Heavy duty space blanket
Grabber Outdoors Original Space Brand All Weather Blanket
Grommeted
Material(s): Astrolar/polyethylene film/aluminum
Dimensions: 84 x 60 in
Weight: 12 ounces
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