The U.S. Air Force (USAF) is experimenting with the idea of harvesting solar energy from space to be returned to Earth as usable energy.
The U.S. Air Force Research Laboratory (AFRL) has posted a video on YouTube describing how the Arachne solar-powered satellite would work.
AFRL Director Gen. Heather Pringle, quoted by Breaking Defense, said a critical review of the Space Solar Power Incremental Demonstration and Research Project (SSPIDR) will be conducted this summer.
SSPIDR aims to use the Arachne satellite, which will convert energy generated by the sun into radio frequency and transmit it to a ground antenna. Once the radio frequency hits the antenna, it is converted into useful power.
If the SSPIDR is successful, it could one day give the U.S. military a big advantage on the modern battlefield and an unlimited source of power for forward operating bases. It would also allow the bases to power future weapons such as lasers and rail guns.
Currently, the military requires massive supply chains and convoys to deliver not only power generation equipment, but also fuel for generators at remote bases.
“Providing a reliable power supply to an advanced operating base is one of the most dangerous parts of ground military operations. Convoys and supply lines are a prime target for adversaries,” says a new AFRL video.
Arachne and SPIRRAL are two subcomponents of AFRL’s Supplemental Space Solar Energy Demonstration and Research (SSPIDR) project. Each of the experiments is to confirm one of five different types of technology underlying future solar-powered satellites.
In theory, space solar power grids could provide electricity to remote military bases without the need for expensive, complicated and vulnerable fuel convoys. But the Air Force is looking further afield and considering solar-powered satellites as possible “refueling stations” for spacecraft operating near the moon or even anywhere in the solar system.
The Department of Defense has long had a love affair with space solar power, but national security space leaders have recently become increasingly interested in the potential for future military operations in near-lunar space. Solar energy satellites could provide easier access and cheaper long-term energy for spacecraft that must traverse the vast amounts of space between Earth and the Moon and the rest of the solar system.
Under the concept of space solar power, satellites with very large solar panels would collect free and ubiquitous solar radiation, convert it on board into microwaves (or optical waves) and transmit that energy to so-called rectennae or rectifying antennas, after which the energy would be distributed to users. (A rectenna is a special type of receiving antenna that converts electromagnetic energy into direct current electricity. They are currently used, for example, in wireless radio communications.)
Arachne, which is SSPIDR’s flagship experiment, is based on the Helios base satellite provided by Northrop Grumman Space Systems under a $25 million contract. The experimental satellite will carry a variety of routine operating systems and an experimental SSPRITE payload (also being developed by Northrop Grumman) designed to demonstrate solar energy harvesting.
The Helios satellite provides power and a hosting platform for the project, while SSPRITE is the system that directly collects solar power, converting that power to radio frequency. SSPRITE consists of a set of solar energy collecting tiles that integrate the entire process of collecting, converting and transmitting energy into a single unit. It’s a potentially game-changing concept, as it allows the technology to scale and opens up the possibility of larger systems that can be used on a much larger scale.