PRAM Solar Powered Satellite Hardware Tested In Orbit
PRAM, the Photovoltaic Radio-frequency Antenna Module created by U.S. Naval Research Laboratory engineers, was tested aboard an Air Force X-37B Orbital Test Vehicle on May 17 of this year. The intent is to see whether it is possible to make terrestrial use of solar energy captured in space.
“To our knowledge, this experiment is the first test in orbit of hardware designed specifically for solar power satellites, which could play a revolutionary role in our energy future,” said Paul Jaffe, PRAM principal investigator.
The 12-inch square tile module will test the ability to harvest power from its solar panel and transform the energy to a radio frequency microwave.
“PRAM converts sunlight for microwave power transmission. We could’ve also converted for optical power transmission,” said Chris Depuma, PRAM program manager. “Converting to optical might make more sense for lunar applications because there’s no atmosphere on the Moon. The disadvantage of optical is you could lose a lot of energy through clouds and atmosphere. “
Depending on the results, the team aims ultimately to build a fully-functional system on a dedicated spacecraft to test the transmission of energy back to Earth. The development of a space solar capability could potentially help provide energy to remote installations like forward operating bases and disaster response areas.
This flight experiment enables researchers to test the hardware in actual space conditions. Incoming sunlight travels through the Earth’s atmosphere, both filtering the spectrum and reducing its brightness. A space solar system traveling above the atmosphere would catch more energy from each of the sunlight’s color bands.
PRAM is the first orbital experiment designed to convert sunlight for microwave power transmission for solar power satellites.
Isaac Asimov's 1941 short story Reason described a solar station which beamed energy around the solar system. However, I think Clifford Simak was earlier (by about one month!) with his Solar Energy Beam from his 1941 short story Masquerade.