Satellites sending electricity to Earth: The European Space Agency’s (ESA) proposal to beam power to Earth from space has just been demonstrated to be feasible, providing the Astro agency with extra firepower as it prepares to request more money to support research into solar energy.
In order to investigate the feasibility of transmitting solar energy from satellites to Earth using microwaves, the European Space Agency (ESA) developed a pilot program named SOLARIS. The SOLARIS project was the agency’s attempt to learn more about the technology necessary to implement the concept and the viability of doing so.
In 2022, the ESA spent time working on many components of SOLARIS, such as releasing two cost/benefit evaluations and hosting an industry day where they and its commercial partners, such as Airbus, gave presentations.
Among the renewable energy sources considered by the ESA, SBSP was deemed to be a viable addition. This past September, Airbus showed it could power a tiny city using microwaves from a distance of 36 meters (118 ft). It’s not quite Alderaan, but it will do for now.
If ministers aren’t already convinced, Airbus’s demonstration may be the deciding factor in allocating further resources to SBSP.
Airbus research project leader Yoann Thueux remarked, “Now that we have successfully tested the main components of a future space-based solar power system on a modest scale, we are ready to take Power Beaming to the next level.”
Although these findings are promising, SOLARIS is limited in its ability to further its mission without further financing from the European Space Agency’s Council of Ministers, which will shortly have its annual meeting at which it considers funding proposals.
The idea of employing solar panels in orbit to transmit microwaves to Earth is not new and has been used in both fiction and reality. As well as NASA, the Japanese space agency, the US Navy, the UK Space Energy Initiative, academic institutions, and the commercial industry have all looked at the possibility.
Yet, China looks to be ahead of the rest of the world in SBSP. The country has conducted testing of a ground-based receiver employing balloons floating at altitudes of up to 300 meters and has plans to conduct experiments at even greater heights.
Is It Just a Space Fantasy, or is There More to It?
SBSP is fascinating for several reasons: It has the potential to aid in the achievement of net-zero energy objectives, to provide electricity around the clock, to gather solar energy more effectively than conventional terrestrial solar arrays due to its elevated location, and to reduce the amount of land required for energy production.
However, the ESA acknowledges that solar power satellites in orbit are not practically possible at this time. Previous research by the ESA and other comparable projects “had revealed no primary technological showstoppers but prohibitive obstacles to make the concept economically feasible due to high launch costs and engineering problems.”
Think about satellites designed to capture sunlight. Each satellite would need to be at least a kilometer in diameter to be worth the effort. To the naked eye, it would look like a little moon in the sky; it would be far too large to be a space station. That’s the same amount of energy produced by a nuclear power plant on Earth, so the satellite could beam it down to us.
However, the receiver on the ground may need to be 10 times as large in order to effectively capture that much energy. The Indian 2GW Pavagada solar farm is around 53 square kilometers in size.
The SBSP microwave receiver would let light and rainfall through, in contrast to terrestrial solar panel arrays. So it’s possible that the soil underneath can be used for farming.
Putting aside issues on Earth, it is improbable that such satellites could be constructed with current technology. The ESA remarked that the assembly of a solar power satellite weighing thousands of tonnes “would certainly need an order of magnitude more launches to construct the International Space Station.”
Instead of seeing that as evidence that SBSP is a waste of research funds, the ESA argued that the work involved will be beneficial to the whole space sector.
The European Space Agency (ESA) identified many potential byproducts of such research and development, including improvements in “photovoltaic and power conversion efficiency,” on-orbit manufacturing, assembly, and servicing, and deployable antenna advancements.
Those who were concerned that these efforts will result in space lasers capable of sparking forest fires need not worry. According to the ESA, microwaves can’t injure cells since they employ a non-ionizing wavelength. However, the SBSP-specific microwave models can only produce a maximum power density of around 250 watts per square meter at the beam’s center, while a human standing at the Earth’s equator at high noon would be exposed to four times that amount of radiation.
However, the ESA has stated that this is just one of several factors and “additional studies” that need to be conducted before the agency can consider SBSP as something that might significantly contribute to Europe’s clean energy ambitions. The ESA stressed that a request to advance to an SBSP development project would only be made “if, and when, these findings are reached.”
That is to say, it’s still too early to start scanning the heavens for the components of a Dyson swarm that will eventually encircle Earth.