By now, everyone knows that solar is the fastest, most economical way to get more kilowatts into the terrestrial grid. Used in satellites, solar energy is also an essential element in both commercial and national defense systems, as recently admitted by the self-named Department of War. In particular, the US Air Force has been lending its muscle to the space solar industry, and they have some pretty good arguments on their side. More Solar Energy For National Defense In its new iteration as the Department of War, the agency has muted its once-vigorous support for solar ever since US President Donald Trump swept back into office last year. However, a sign of persistent interest crossed the CleanTechnica radar over the weekend, when researchers in Germany unveiled a germanium-based solar module that set a new world record for solar conversion efficiency. Following some digging through the Intertubes, we find that germanium is in short supply here in the US, and that’s a problem. Germanium is used in high-end solar cells and it also appears in infrared optics, night vision systems, surveillance windows, and weapon sights among other defense applications. In January, DoW addressed the germanium shortfall with an award of $18.1 million to a domestic producer, aimed at pumping up the onshore supply chain. In a press statement announcing the award, DoW took note of multiple defense applications. Solar also made the cut. “Germanium is also essential for solar cells that power military and civilian satellites,” the agency stated. No kidding! The US Air Force totally agrees. As described by USAF, solar represents a next-level logistics improvement over fossil fuels. “Today, expeditionary energy relies on diesel generators, fuel convoys and aerial resupply. These systems increase lift requirements, create detectable signatures and introduce operational risk,” USAF explained last March, in an article explaining its interest in solar energy. Space-Based Solar Is Coming For Your Fossil Fuels The USAF article describes how solar can reduce if not eliminate fuel resupply risks to pilots, crews, and aircraft. The idea is to deploy space-based systems that harvest solar energy in orbit, 24/7 regardless of the weather, and beam it down to receivers on Earth. When first introduced in the early 2000’s, the concept seemed too futuristic for any real shot at reality. However, the technology pieces are in place, the cost of rocket launches has dropped, and private sector stakeholders are closing in on the demonstration phase (see more space-based solar background here). USAF does not intend to be left out of the mix. In May, they issued a contract to the US firm Overview Energy to demonstrate how space-based solar systems could be deployed to power large, remote military operations. Seal Of Approval From USAF Air University Overview is among the stakeholders racing to make space-to-Earth solar technology happen within the next 10 years. The company has been testing its equipment on airborne platforms and expects to send it orbiting around the Earth sometime in 2028. Around 2030, they anticipate megawatt-level delivery to Earth, with plenty more where that comes from. “In the early 2030s, we’ll be capable of delivering more than a gigawatt of 24/7 clean energy anywhere on Earth,” the company has stated. The USAF is among those sorting out the Earth-bound end of things. The article posted in March describes research under way at USAF’s academic branch, Air University, with a focus on fuel resupply in the Indo-Pacific region. The project is titled PERSEUS for Pacific Expeditionary Resilient Solar Energy from Uninterrupted Space. The researchers do not advocate for putting the technology to use any time soon, taking note of further R&D work in addition to cost limitations. However, the project does does describe how space solar could be used in defense applications, once deployed. So far, the researchers have demonstrated a scaled proof of concept model for wireless energy transmission from a satellite to a mobile receiver, based on an analysis from NASA. The mobility element is something that distinguishes the PERSEUS project from other space solar technologies, which rely on static receiving stations. For defense purposes, the ability of the receiver to keep up with force movements is crucial. “It shows that space-based solar power could become a future capability that reduces logistics burdens, supports distributed operations and increases operational tempo for the Air Force and the Joint Force,” USAF concludes. “Space-based solar power offers a way to reduce reliance on vulnerable fuel supply chains. It presents a future where energy can be delivered to distributed forces when and where it is needed,” they emphasize. Plenty More Solar Energy Where That Came From Here on Earth, the President has tried, and failed, to stop the US solar industry from dominating all other energy sources for new, utility-scale capacity additions to the nation’s grid. Solar manufacturers in the US have also been ramping up operations in anticipation of persistent demand for new utility-scale solar power plants. Manufacturing activity in the space solar field is somewhat more difficult to track, but some recent developments in the field indicate that the demand for solar energy in space is also a force to be reckoned with. On June 4, the US defense supplier York Space Systems announced that it has acquired the space solar startup Solestial. “The acquisition secures a domestic source for critical space solar capability at a moment much of the satellite manufacturing industry remains deeply exposed to Chinese-controlled source materials, delivering a meaningful strategic advantage through a secured, U.S.-sourced supply chain,” York explained. If Solestial rings a bell, it should. The company surfaced on the pages of CleanTechnica back in 2023, when NASA tapped it for an award of $850,000 under a project titled, “Next Generation Silicon Based Solar Arrays for Space Stations and Other Permanent Space Infrastructure,” deploying the company’s ultra-thin, ultra-durable, self-repairing silicon solar cells. The 2023 award followed on the heels of previous development support from NASA and USAF, too. By November of 2024 Solestial was preparing its new solar cells for volume production. Earlier this year the company also announced the purchase of specialized manufacturing equipment from Meyer Burger, a once-promising European solar firm that went bankrupt last year. “The strategic acquisition enables Solestial to completely process its self-healing silicon solar technology from wafer to cell in house, significantly expanding its manufacturing capabilities and supply chain control,” Solestial announced on January 21. “Solestial plans to transition the limited solar cell manufacturing currently conducted in Germany to the United States, resulting in a fully integrated cell to module solar manufacturing operation based in the United States,” the company added. That helps explain why York spotted a ripe opportunity to grow its foothold in the space solar field. As for beaming energy from space to Earth, don’t jump the gun just yet. Solestial has stated that its primary market is in-space applications. Photo: The US Air Force is among those recognizing that solar energy is an essential tool in the national defense toolkit, with the potential to replace treacherous fuel resupply missions for ground operations (cropped, courtesy of US Army).
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