Today, space satellites serve the U.S. military’s communication and intelligence needs. Soon, though, they may take on a radical new function: generating abundant clean energy. The Air Force Research Laboratory (AFRL) and partners are on a mission to design satellites that harvest energy from the sun’s rays and beam them in continuous, steady streams down to military bases on Earth.

Antennas at the recipient bases would receive the beams and convert them into enough electricity to fully power homes, offices, and workstations base-wide.

It’s an ambitious idea. And a polarizing one, it seems.

“Proponents have portrayed it as the smartest, most comprehensive energy solution available, while detractors have seen it as an insanely expensive scheme that will never work,” wrote the Aerospace Corp. in a recent study.

But AFRL is taking a chance on the idea. So is Northrop Grumman, who’s working with the AFRL’s Space Solar Power Incremental Demonstrations and Research (SSPIDR) initiative, a “collection of ground and flight experiments designed to mature different critical technologies needed to build an operational space-based solar power beaming system,” according to an AFRL statement.

AFRL has given the company $100 million to build the parts for a future spacecraft named–—appropriately for a project with a name spelled like a SSPIDR—”Arachne,” which the agency aims to launch into space in 2025. The company has thrown an additional $15 million of its own money into the project.

Northrop Grumman hit two important production milestones in the last two months. First was completion and successful testing of a new “tile”—like a solar cell, but much more durable—for collecting and storing the sun’s energy. Arachne will carry arrays of these tiles when it goes into orbit.

Northrop Grumman also recently completed the “bus,” the core body component that will hold key parts of the spacecraft’s power, communications, and control systems. The bus will also store the Space Solar Power Radio Frequency Integrated Transmission Experiment (SSPRITE), which will collect and convert the solar energy prior to its relay to the ground. Northropp Grumman is still working on the SSPRITE.

Defense officials inside and outside AFRL are interested in space-based solar because it could provide even the most remote military bases, in the hardest-to-reach locations, access around-the-clock to all the energy they need. Right now, those bases rely on fuel deliveries, via aircraft or truck convoys. Which does not always pan out in wartime, when enemy forces often seize convoys before they can make their deliveries.

However, the enemy will have a much harder time stopping energy beams shooting down from space.

Solar in the Dark of Night

There are more reasons to get excited about space-based solar: Unlike ground-based solar panels, it doesn’t need daylight or a cloudless sky. It’s raining? No problem: Those energy beams will cut straight through clouds and raindrops.

They can even–an impossible feat for a solar panel down on Earth–keep the energy flowing at nighttime. Solar satellites over on the sun-facing side of Earth orbit could beam their energy to satellites on the dark side, which will relay them down through the night sky to the base’s antennas.

With solar arrays up in space, U.S. forces on the ground would get instant access to all the energy they need, whenever they need it. In any daytime or nighttime hour, in any kind of weather, the beams will keep on running.

Civilian Solar Power

Solar energy could power civilian homes, as well. Defense officials envision these spacecraft bringing affordable clean energy to civilian communities down the road, as well.

“Incorporating space solar power into America’s space and climate agenda could not only provide yet another arrow in the quiver to address climate change but provide novel ways to engage industry, the public and international partners,” reads an AFRL report.

Some of the best technologies the civilian world enjoys were born in the defense sector. GPS systems made a crossover from military to civilian life. As did mobile phones. And the Internet itself. In a few years (or more), maybe space solar power will be next.

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Rick Docksai is a Department of Defense writer-editor who covers defense, public policy, and science and technology news. He earned a Master's Degree in Journalism from the University of Maryland in 2007.