MPI Outdoors


Let's Get Technical

There are more than a few people out there who want to know some of the technical aspects of our unique products. The "why they work" and "how they work" in keeping you warm and protected, which is the purpose of the following article. I hope you find it both interesting and informative. You have heard that "this is not rocket science" but in some way this really is, as the principles were explored and expanded on by NASA in the early 1960's for their proposed use in the Apollo missions.

The sensations of heat and cold are induced by the abnormal gain or loss of heat from the body. In a warm environment wherein the ambient temperature is greater than that of the body, it absorbs heat and we feel warm. Conversely, when the temperature of the atmosphere around us is less than that of the body, it loses heat at an accelerated rate and we feel cold. In order to operate efficiently, effectively and to maintain good health, we all know that normal body temperature should be 98.6· F.

The body has built in mechanisms to combat temperature variations. When we over exert and feel hot, the body perspires, the evaporation of which provides a cooling effect. Conversely, cold causes us to shiver and the induced muscular activity generates a certain level of warmth.

The body can be warmed in several ways; (1) wearing several layers of clothing to provide insulation barriers, (2) heating of the air in a room or enclosure to raise the ambient temperature, (3) carefully ingesting hot liquids to slowly warm the internal engine, and (4) if possible by exercise to stimulate and accelerate the internal organs to create heat through exercise.

To cool the body one can (1) wear lighter weight, light colors or no clothing, to allow the body to perspire and cool naturally, (2) cool the surrounding air mass (air conditioning), (3) consume liquids or (4) find shade and allow the body to rest.

The body loses heat in five (5) ways:

  1. Radiation
  2. Conduction
  3. Convection
  4. Evaporation
  5. Vapor loss from breathing

The U.S. Army Quartermaster Testing Laboratories in Natick, MA breaks this heat loss down as follows:

  1. Radiation 38.5%
  2. Convection 31.5%
  3. Evaporation/Vapor loss 27.0%
  4. Undetermined 03.0%


Radiation is energy that is emitted in the form of waves, these waves can be:

  • Sound Waves
  • Radio Waves
  • Infra Red Energy
  • Visible Light
  • Ultra Violet Light
  • X-Rays
  • Gamma Rays

The rays that are of direct concern in helping to maintain your body heat are the Infra-Red Radiation. These lie between wave lengths of 10-1 and 10-4 cm. The ideal way to control and direct this type of energy is to allow it to bounce off a reflective surface. In the case of a simple mirror, energy is reflected so that a clear image can be seen, your reflection. But this mirror also reflects other forms of energy including Infra-Red. You may have heard of a solar furnace which develops some of the highest temperatures known to man. This furnace is a series of highly polished parabolic mirrors focused to concentrate infra red energy at one point.

The SPACE® Brand BLANKETS utilize this principle through its highly reflective layer of vapor deposited aluminum. This "barrier" slows the loss of body heat caused by the emission of radiated escaping heat from the body and captures it and reflects it back to its source. In providing the means with which to preserve this loss of body heat, and reflecting it back, the SPACE® Brand BLANKETS help to maintain the comfort level within the human body.


You should be familiar with the cold feeling which occurs when you are sitting near a window in the winter. This "chilly feeling" is not that cold air is leaking in open holes around the window but rather it is air flowing off of the glass surface. This air film is cooled by the cold glass, flows downward towards the floor and replaces warmer air by creating air circulation in the room. Cold air falls—hot air rises. This "convective" force causes additional heat from within the room to be transferred and lost directly at the window surface. (fogging-misting-water vapor). This problem can be reduced by Thermo-pane windows, storm windows, etc., which trap a layer of dead air between two glass surfaces. This trapped air serves as an excellent insulator since still air is a poor conductor.

The SPACE® Brand BLANKETS help create an "air barrier" by the nature of the material, it being windproof, waterproof and reflective and the "trapped air" from your body held inside the blanket. This helps keep you warm and protected from the elements.


Moisture loss from the body occurs both from the surface of the skin and from exhaled saturated air. In both cases, the moisture is vaporized, is diluted with air and mechanically removed from the body. If this moisture is allowed to collect and re-condense on a cooler surface like clothing the body will feel cold and uncomfortable and reduce the insulative properties of the clothing.

The SPACE® Brand BLANKETS by their nature being "wrapped around" you with openings at the closure, help to create a natural air passage flow. Enough fresh air circulates inside the blanket creating movement to dissipate excess moisture into the outside environment as it exits. It is good to remember that opening and repositioning the blanket from time to time helps facilitate this vapor expulsion process.


The loss of heat from conduction is caused by body pressure on a cold surface, i.e. sitting on a rock. Insulate "your bottom" with a build up of pine needles, dried leaves, a foam pad, or whatever to prevent contact with the cold surface. The SPACE® Brand BLANKETS will not conduct away your body heat UNLESS the surface is pressed tightly against a cold surface like the ground---INSULATE.

In simple terms, SPACE® Brand BLANKETS:

  1. Reflect and help to retain radiated body heat—helping to utilize the natural effects of RADIATION as an added insulator.
  2. Helps to create a wind barrier from the biting cold which helps to ally the loss of body heat through CONVECTION.
  3. Are lightweight and easy to use, allowing for easy opening and closing to help aid in the dispersal of moisture build up caused by EVAPORATION.
  4. The plastic film substrates are designed to form a non-breathable barrier and will help prevent excessive loss of heat through direct CONDUCTION.

Other technical "stuff" of interest:


  • Have only 1 millionth of an inch of precise vapor deposited aluminum applied to the film surface, this forms the needed reflective barrier to prevent pass through transmission of radiated energy.
  • It is a know fact that body heat is emitted along a certain wave length path. The right film substrate is critical and must be properly metallized with an exact deposition of pure aluminum to become a barrier from emissions against this transmission. Then and only then can it be effective in capturing the radiated heat and returning it back to the source, your body.
  • A direct by-product of materials actually developed for the NASA space programs starting with the Pegasus weather balloon launch program of the late 1950's, through to and including use of reflective film barriers on the current Shuttle missions.
  • 100% American made, since 1964, using only high performance domestic materials, Quality American equipment and focused labor. Off-shore manufactured copies can not always be relied upon for their consistency of the important physical properties needed to create an effective and useful barrier.

If nothing else, you now have a lot of technical words to banter about. We really hope that you have a somewhat better understanding that the SPACE® Brand BLANKETS are more than just a simple piece of plastic material. We trust that you will now have the confidence to carry one or more with you on your outdoor treks, just in case you may someday need its life saving properties.

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