Space power plant projects face a range of engineering challenges. One of them is the transfer of energy collected by solar panels in geostationary orbit to Earth. The British company Space Solar not only offered a concise technical solution, but also successfully tested its reduced prototype.
At first glance, there is nothing technically impossible about the idea of a solar power plant that transmits energy to Earth. We take solar cells, assemble a huge battery from them, connect it to a microwave emitter — and send it to geostationary near-Earth orbit (GEO). We only need a bigger rocket, and reliable folding farms to support huge areas of panels. It seems to be simple, but the devil lies in the little things.
For example, a satellite on the GSO only looks tightly "frozen" to an observer from Earth. It is still moving in orbit around the planet. This means that in order for its panels to always face the Sun, it needs to rotate. At the same time, the emitter of microwave radio waves must remain oriented to the Earth, otherwise what is the point of the whole idea. Simply put, the antenna for energy transmission needs to be fixed on a hinge. The trouble is that any mechanics performs very poorly in open space, and it is extremely difficult to make it reliable.
The startup Space Solar from the UK has solved this problem radically. She has created a new emitter capable of continuously focusing the radio beam in any direction. In a recent press release on its website, the company talked about testing a prototype of such a device. The tests were carried out in a laboratory at Queens University in Belfast. The development confirmed the operability of the concept, the radio beam hit the target regardless of the orientation of the emitter, while its characteristics (positioning accuracy, diameter) were always in the required range.
The innovative emitter is called Harrier, and a smaller version with a diameter of 50 centimeters was tested in the laboratory. The final project involves the creation of an antenna with a diameter of 1.7 kilometers, capable of transmitting gigawatts of energy from space to Earth. In addition, Space Solar plans to use its development in ground-based devices.
The details of the technology, as well as the power of the tested device, are not disclosed. As far as can be judged from the photographs published by the company, the Harrier is an active phased array of complex shape, placed on a flattened cylindrical truss. This design implies a 360—degree circular "view" of the radio beam, but not spherical - dead zones are inevitable from above and below the cylinder.
Not only the efficiency of a promising space power plant, but also its safety depends on how accurately Harrier can shape the beam. Few people would want gigawatts of energy to miss the receiving antenna on Earth.
In its press release, Space Solar provided few details, only shared the success of the tests. However, the UK Space Agency is closely monitoring the project, and its representative was present at the prototype test. It can be assumed that the Harrier meets the minimum safety requirements for the future product.