Naval Research Lab Investigating Space-Based Solar Power

The US Air Force has a super secret unmanned airplane called the X-37B that is capable of long duration space flight before it returns to Earth intact. A scaled down version of the Space Shuttle, the X-37B  is 29 feet long and 9.5 feet tall with a wingspan of about 15 feet. It has a cargo bay about the size of a full size pickup truck and weighs 11,000 lbs at launch, according to Space.com.

The sixth flight of the X-37B began last Saturday, May 16. The OTV-5 mission launched on Sept. 7, 2017 by a SpaceX’s Falcon 9 rocket lasted 780 days. The purpose of each flight and the contents of its cargo compartment are closely guarded secrets, but PV Magazine reports that part of the latest payload is a device created by the Naval Research Laboratory that will evaluate the potential for collecting solar energy in space and beaming it back to Earth using microwaves.

Dubbed the Photovoltaic Radio-frequency Antenna Module, it is a 12-inch square panel that converts sunlight into radio frequency microwaves. The panel has an additional layer meant to capture more light in the blue spectrum. “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,” the research group says. “A space solar system traveling above the atmosphere would catch more energy from each of the sunlight’s color bands.”

Solar power from space has been a dream for decades. NASA and the Department of Energy began experiments into the technology in the 70s. China says it will be a leader in space-based solar power. In 2014, the Japan Aerospace Exploration Agency announced its intention to build orbiting solar power stations with a combined capacity of 1 gigawatt by 2030.

The technical challenges of space-based solar power are immense. Perhaps the results of this latest research will move the process away from the theoretical and closer to reality.