Space-Based Solar Power is a Nascent Space Tech Application, but SpaceX is Changing the Cost Equation in its Favor

As 2024 drew to a close, the recently rebranded Space Tech team has opted to write a “space tech-oriented” ABI Insight. Many ABI Insights, to date, have been on Satellite Communications (SatCom)—a very effective utilization of space—but a number of novel technologies are on the cusp of commercialization. ABI Research will be pushing our research efforts in these sectors. This ABI Insight focuses on Space-Based Solar Power (SBSP), previously covered in “Are Solar Energy Transmissions from Satellites the Next Frontier for Renewable Energy?” as momentum is building in this sector. In 4Q 2024, both companies dedicated to SBSP, Aetherflux (United States) and Space Solar (United Kingdom), have joined a growing field of budding SBSP solution providers:

• Aetherflux: In October 2024, the firm declared its intentions to develop and ultimately deploy a constellation of satellites in Low Earth Orbit (LEO) that will collect solar power and beam it to Earth using Infrared (IR) lasers. The company plans to launch a small satellite demo by early 2026. Rather than a large surface area solar collector, Aetherflux's strategy relies on an incremental constellation of smaller satellites in LEO that can grow over time. Also, the SBSP provider plans to use IR lasers to transmit the converted solar to electrical power to a ground-based receiver (approximately 10 square meters in size). The spacecraft bus is manufactured by Apex (United States) and can transmit potentially Kilowatts (kW) of power to Earth. Aetherflux is targeting the government defense sector, such as forward operating bases where the challenges of arranging the supply of fuel or electricity may be highly constrained.
• Space Solar: More recently, Space Solar announced intentions to be operational by 2030 with an initial capacity of 30 Megawatts (MW). The spacecraft bus, which can operate in Medium Earth Orbit (MEO), Highly Elliptical Orbit (HEO), and Geosynchronous Orbit (GSO), will start at 60 tonnes and have a 400-Meter (m) diameter solar collector. The collected solar energy would be transmitted to Earth as a microwave beam (e.g., in the 5.8 Gigahertz (GHz) band). The ground station (a.k.a. a rectenna) will have an initial diameter of 1 Kilometer (km), but could require up to 4 km for later configurations that could support power delivery in the 600 Megawatt (MW) range. The deployed spacecraft, with its unfurled solar panels, would dwarf the International Space Station (ISS) at 110 meters or even terrestrial man-made objects such as the Eiffel Tower (300 meters), but the company is confident the spacecraft bus could be remarkably launched in a “single” SpaceX Starship launch. It is estimated that 30 MW can provide electricity to around 9,000 U.S. homes. Space Solar also has a committed first customer, Reykjavík Energy in Iceland.

There is a lot to unfold here. These are two very innovative companies, but, in fact, the SBSP concept has been evaluated and tinkered with since the mid-1970s—pretty much since the first solar panels were deployed on spacecraft. SBSP concepts have been researched by companies and government agencies in China, Japan, India, Russia, the United Kingdom, and the United States. Converting solar energy to usable forms of energy in space does have significant merits:

• Solar power can be collected pretty much 24/7.
• The amount of solar energy connected per square centimeter is 10X compared to ground level, as the atmosphere, water droplet, and pollution scatter the light before reaching the ground.
• The delivery of the wireless power could be redirected to additional or multiple locations with minimal effort.

On the flip-side, there are hurdles to overcome:

• While water and vegetation (even animal) damage would be mitigated, the equipment has to be hardened to the consequences of space junk, micro-meteorites, and cosmic rays/solar flares that can damage the electrical and/or structural integrity of the SBSP spacecraft.
• The logistical effort to achieve the successful launch and deployment of a decent-sized solar energy collector into orbit.
• The economic cost of getting the SBSP spacecraft into orbit remains a challenge.

The amount of activity in the SBSP sector in 2024 was reflective of a number of innovations taking place. The principal one is the rise of SpaceX, and its payload launch systems that have radically changed the cost equation of delivering a per unit Kilogram (kg) into orbit, which is now very much in the range of US$2,300 to US$3,059 per kg, from US$10,000+ per kg just 24 years ago. Some industry sources estimate that SBSP can become viable once the costs have fallen under US$200 per kg. (Note: This assumption has yet to be fully validated by ABI Research, which we plan to do in 2025.) Because SpaceX can launch spacecraft at an external price of US$2,300 to US$3,059 per kg, the commercialization scenario where Starship brings prices down even further is starting to look very promising.

With the arrival of SpaceX's Starship, it’s not just the cost of launching payloads that will change. The increased capsule space required to accommodate a folded-up SBSP satellite will make commercial SBSP even more viable, a development that has only recently become possible with Falcon 9 and Starship. Looking further in the future, it will be possible for robotics and self-assembly mechanical systems to help integrate two or more SBSP payloads into a larger deployment.

It should also be noted that the power delivery systems are also improving. Space Solar’s panels are made up of 20,000 layers to maximize solar capture of electricity. That electrical power can then be transmitted to Earth via microwaves or IR lasers. Microwave transmission technology is more mature, but conversion from electrical power to Radio Frequency (RF) power has a low yield (potentially 85% loss). Microwaves do require a large receiver to receive RF power, but they can be placed in remote areas to keep receiver deployment costs low. It should also be noted that the RF low microwave transmission is harmless to people and wildlife. In the other SBSP scenario, IR lasers are used. IR lasers are more compact, and the receiver is only 10 meters in diameter. Conversion of electrical power into IR lasers is significantly higher (50% or higher), but the IR laser transmission can experience attenuation that is a function of the amount of water vapor in the air. The IR laser beam could be reallocated to receivers that are not experiencing heavy rainfall/cloud cover.

The world very much needs to pivot away from fossil fuels. Many countries are embracing green energy solutions such as terrestrial wind, wave-action, and solar energy. SBSP could gain traction in markets that have a lot of land mass in relation to occupied land (e.g., Iceland). ABI Research will be delving into SBSP technologies, economics, and potential adoption. From initial research, there are at least 55 SBSP enterprises, with differing degrees of backing, jockeying for position.