December 27th, 2020 by Tina Casey
I know, right!? It sounds crazy, but plans are in the works to harvest solar power in space and beam it down to you wherever you are, any time, any place, any weather. Kind of like GPS, only without the disembodied voice ordering you around. When CleanTechnica checked into the topic of space-based solar a while back, it seemed like one of those things that could happen, eventually, but now that a key component is in place, eventually is turning into just a few years from now.
Solar Power From Outer Space
First things first: why bother harvesting solar power in outer space when there is so much of it right here on Earth.
That’s a good question. The problem isn’t not enough solar on Earth. It’s not enough solar at the right place and time. And then there’s that pesky issue of competing land use interests. If you could grab clean kilowatts from outer space on an as-needed basis, you wouldn’t need to invest the big bucks in new transmission infrastructure, and you wouldn’t have to worry about sacrificing farmland or nature habitats for solar farms.
CleanTechnica first took note of space-based solar power back in 2012, when the US-based organization National Space Society launched a solar-scavenging space mission with a research team based in India.
Sounds kooky, right? Wrong! In 2014, CleanTechnica ears perked up even more when the Naval Research Laboratory dipped its toe in the space solar waters under the direction of spacecraft engineer Dr. Paul Jaffe. From Jaffe’s perspective, the technology elements were already at hand. The sticking point was how to trim them down to a manageable size and weight. Here’s what we said back then:
To tackle the weight problem, Jaffe has developed two related ultra-light solar modules. One is a high-efficiency “sandwich” style module that converts solar energy to a radio frequency, with an integrated antenna to transmit power.
The other is a patent pending “step” variation that opens the sandwich out. For those of you playing accordion at home, you can think of the sandwich as a closed bellows. With everything pushed together that creates thermal inefficiencies, but if you open it out you can enable heat to radiate more efficiently.
Beam Me Down Some Solar Power, Scotty
As further proof of the non-kookiness of the idea, in 2015, Northrup Grumman threw its hat into the space solar ring, in a partnership with CalTech, which happens to run NASA’s Jet Propulsion Laboratory. So, yes, not kooky at all.
CalTech’s Space Solar Power project aims at the same ultralight, foldable target, with an integrated radio frequency converter that enables wireless transmission of solar energy from a spacecraft down to Earth.
“Integration of solar power and RF conversion in one element avoids a power distribution network throughout the structure, further reducing weight and complexity. This concept enables scalability and mitigates local element failure impact on other parts of the system,” CalTech explains.
Solar Beaming, Coming Soon From A Spacecraft Near You
That brings us up to the latest news. We’re not sure what happened to the Naval Research Laboratory (if you know anything, drop us a note in the comment thread), but earlier this month, the Air Force Research Laboratory announced that its “Space Solar Power Incremental Demonstrations and Research” solar beaming project has just received the first key component for its Arachne spacecraft, from none other than Northrup Grumman.
If you caught the SSPIDR acronym, that explains the Arachne moniker. There are a bunch of other acronyms and names of things involved, but the important one to remember is Helios, with is the name of the component supplied to the lab by Northrup Grumman.
In spacecraftspeak Helios is the “bus,” which is the element that houses the payload, which in this case is the platform for conducting all the space solar beaming experiments. In days of yore, the Air Force Research Lab would have had to devote some time and energy to designing and building its own bus, but thanks to a public-private partnership, the heavy lifting was handed off to Northrup Grumman, leaving the lab free to focus on the science.
The Arachne team is quite excited about the advantages of using a commoditized, off-the-shelf bus rather than having to develop, build, and test one from scratch. Here, let’s have Arachne chief engineer Kevin Gleichmann explain it all (watch that first acronym, it’s a doozy):
“The idea to use the ESPA ring as the main structure of a spacecraft started with AFRL’s [Demonstration and Science Experiments (DSX)] program and eventually led to AFRL’s EAGLE program. As a result of EAGLE, the ESPA platform has successfully been transitioned to industry and can be purchased as a commoditized spacecraft.
“This essentially allows AFRL to buy a spacecraft off the shelf and eliminate it from the critical path of our flight programs, allowing AFRL to concentrate our time, money, and efforts in bringing cutting-edge technologies to our warfighters.”
We Are ThisClose To Infinite Solar Power From Space
Got all that? Good!
Of course, it’s not as simple as plugging Helios in and maybe giving it a kick or two to get started. The Arachne tea still has to figure out the optimal systems for interfacing with the bus and its primary payload, which is officially titled the Space Solar Power Radio Frequency Integrated Transmission Experiment, and Northrop Grumman is still working on that end.
Aside from the Arachne spacecraft, there will be a whole raft of associated experiments on Earth and up in space, because the SSPIDR solar beaming project is focusing on five areas: Deployable Structures, Energy Generation, Thermal, Radio Frequency Beaming, and Metrology.
Long story short, don’t hold your breath for GPS-style solar power to beam into your electric vehicle whenever you need to recharge your battery. However, Arachne is expected to launch in 2024 with Helios and the SSPRITE payload on board, at which point the lab expects to demonstrate those “sandwich tiles” and other systems involved in converting solar energy to radio frequency power.
What Does It All Mean?
For the here and now, we’ll just have to muddle through with plain old Earth-based solar power. In that regard, it’s helpful to note that transmission issues are not insurmountable. The emerging trends of community-based solar and solar + storage could help ease the demand for major new transmission infrastructure.
Come to think of it, with the cost of Earth-bound solar power continuing to drop like a rock, the need for space solar power is not altogether evident. The last time we checked, the estimated cost of a solar kilowatt from space was a lot higher than its terrestrial cousin.
However, if you caught that observation from the Air Force Research Laboratory about warfighters, that’s one area in which price is no object.
That circles right back around to that thing about GPS, which after all was initially developed with military purpose in mind.
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Image: “The image depicts AFRL’s Space Solar Power Incremental and Demonstrations Research Project beaming solar power from space to earth. SSPIDR consists of several small-scale flight experiments that will mature technology needed to build a prototype solar power distribution system” (courtesy of AFRL).
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