According to a study by Astrostrom for ESA, future Moon bases could be powered by a giant space butterfly called the Greater Earth Lunar Power Station (GEO-LPS) covered with solar panels made from lunar materials beaming microwaves to the surface.
One of the major design concerns in setting up a lunar base is finding a reliable means of powering it. Solar power might seem the obvious answer, but with lunar nights lasting 14 Earth days, it isn’t a practical option. However, though the most promising alternative is currently a small nuclear reactor, solar may not be out of the running.
The idea of solar power plants in space has been around for well over half a century. On Earth, solar panels are limited by night time, atmospheric haze, and bad weather, making them only capable of intermittent power generation with limited efficiency. On the other hand, in space, where there is no night and no atmosphere, solar power becomes very attractive.
According to the new ESA study, a space-based solar plant might be particularly attractive for lunar outposts. The focus of the study is the new GEO-LPS design, which consists of a crewed station core from which span a pair of V-shaped solar panels that are curved in a helix configuration to provide structural support. These panels covering a square kilometer (0.38 square miles) are equipped with iron pyrite monograin-layer solar cells and built-in antennae for beaming the collected energy to receptors on the Moon at a yield of 23 megawatts.
The whole assembly would be located at Earth-Moon Lagrange Point 2 located 61,350 km (38,308 miles) from the lunar surface, where the gravitational pull of the Earth and the Moon balance one another out, providing a point that a station can orbit about as it would a solid body. Here, GEO-LPS can act not only as a power station, but as a space lab with artificial gravity capabilities, a base for deep space missions, and even a tourist destination.
However, what is particularly interesting about the study is that it claims that the needed technology currently exists or is under development on Earth that would allow GEO-LPS to be built using resources mined on the Moon using robotic and teleoperated systems, removing one of the major obstacles of building such stations using components manufactured on Earth. By using the Moon, the lower gravity would greatly reduce launch costs and the modules for the station could be made to self-assemble to lower labor costs.
“Launching large numbers of gigawatt-scale solar power satellites into orbit from the surface of the Earth would run into the problem of a lack of launch capacity as well as potentially significant atmospheric pollution,” said Sanjay Vijendran, overseeing ESA’s SOLARIS R&D initiative. “But once a concept like GEO-LPS has proven the component manufacturing processes and assembly concept of a solar power satellite in lunar orbit, it can then be scaled up to produce further solar power satellites from lunar resources to serve Earth.
“This would also create many other benefits in addition to providing sufficient clean energy for Earth, including the development of a cislunar transportation system, mining, processing, and manufacturing facilities on the Moon and in orbit resulting in a two-planet economy and the birth of a spacefaring civilization.”