The  Photovoltaic Radio-frequency Antenna Module is a 12-inch square tile module. It is the first orbital experiment designed to convert sunlight into radio frequency microwave. The combination of photovoltaic and EM technologies is called PRAM which helps to capture energy from space and then transfer it to power stations on Earth.


Demanding for source of energy is growing more, even if the sources are from outer space. The U.S. Naval Research Laboratory (NRL) found that the solar energy captured in space may serve as an energy source for terrestrial application on earth over the years with the help of Photovoltaic Radio-Frequency Antenna Module (PRAM) experiment. This experiment resulted in launching the PRAM energy-capturing device aboard the U.S. Air Force X-37B Orbital Test Vehicle last May 17, 2020. This experiment of hardware designed specifically for solar power satellites is the first test in orbit which could play an important role in our energy future


The panel, called the Photovoltaic Radio-Frequency Antenna Module (PRAM) which is  roughly in the size of a pizza box was mounted to the Pentagon’s top-secret X-37B drone. This drone loops around Earth every 90 minutes. PRAM is like “sandwich” modules where one side it has a photovoltaic panel, middle it has electronics and the other side it has an antenna. The photovoltaic panel receives solar energy, the electronics convert that direct current to radio-frequency signals and the antenna which beam power away. Since the sunlight isn’t blocked by the Earth’s atmosphere, the panel receive more illumination than it was on Earth. So far, it has generated about 10 watts which is plenty to power a tablet.


As this drone is traveling above the atmosphere it can catch more energy from each of the sunlight’s colour bands.

This module sends data on a regular basis which helps the scientist to better understand the mechanical and electrical performance requirements over time that will be needed for the long-term success of a power satellite network.

It also delivers valuable data to advance space solar and power beaming research.

Converting PRAM into an optical power transmission might make more sense for lunar applications because there’s no atmosphere on the Moon, but the disadvantage is it could lose a lot of energy through clouds and atmosphere.


For the next iteration of experiments and demonstrations for space solar, the PRAM has successfully layered a foundation. The scientist aims ultimately to build a fully-functional system on a dedicated spacecraft, depending on the experiment results. This helps to test the transmission of energy back to Earth. This development in the space solar could potentially help provide energy to many remote installations which are like forward operating bases and disaster response areas.