For Space Exploration by the Apollo program, NASA helped develop a thin aluminum metalized film, which reflected 95% of the radiant heat. A metalized film was used to protect spacecraft, equipment, and astronauts from thermal radiation or to retain heat in the extreme temperature fluctuations of space. The aluminum was vacuum-coated to a thin film, and applied to the base of the Apollo landing vehicles, in addition to numerous other NASA projects like the James Webb Space Telescope and Skylab. In the vacuum of space where temperatures can range from 250 °F above to 400 °F below zero,  heat transfer is only by radiation, so a radiant barrier is much more effective than it is on earth, where 5% to 45% of the heat transfer can still occur via convection and conduction, even when an effective radiant barrier is deployed. Radiant barrier is a Space Foundation Certified Space Technology(TM). Radiant barrier was inducted into the Space Technology Hall of Fame in 1996.

Our patented metal batten and counter batten system incorporates  a radiant vapor barrier underlayment.  Metal battens and counter battens provide the required air space for radiant vapour barriers to effectively deflect 97% of radiant energy, while also providing a drainage plane for moisture that builds up under the panels. 

You can find plenty of valuable information on Radiant Barriers from RIMA at  http://www.rimainternational.org/ 

To illustrate how radiant barriers work, watch these informative videos by Attic Foil.com

Residential Compliance Manual for California's 2005 Energy Efficiency Standards:
www.energy.ca.gov/title24/2005standards/residential_manual.html

California Energy Commission educational video on radiant barriers: 
www.energyvideos.com/bldvid.php?P=CA&A=5&S=rad

California Energy Commission website for cool roof research: www.consumerenergycenter.org/coolroof

Cool Roof Rating Council maintains a listing of cool roof products: 
www.coolroofs.org

Oak Ridge National Laboratory's Radiation Control Calculator can help estimate the potential savings for cool roofs. At the website, click on "interactive calculators" and run the "radiation control calculator":www.ornl.gov/roofs+walls

Lawrence Berkeley National Laboratory (LBNL) maintains a Cool Roofing Materials Database:http://eetd.lbl.gov/coolroof

Building Green, publisher of Environmental Building News, has cool roof information:www.buildinggreen.com

Fact sheet on attic ventilation by U.S. Department of Energy:www.eere.energy.gov/buildings/info/documents/pdfs/26450.pdf