Mining, mobile internet, even manufacturing – the vast vacuum of space holds great promise for the future of many sectors.
The decades to come will see thousands more 5G satellites launched and projects targeting asteroids’ mineral wealth, while some hope that orbital microgravity could be the ideal enabler for computer-chip manufacturing.
Energy, on the other hand, seems a resolutely earthbound industry. Each year we tap more of the renewable resources available to us, while commercial nuclear fusion seems closer and closer. Even if we could access some space-based power source, how would we transmit it down to us?
That question and many more could be answered by an ambitious project from the government, which has commissioned Frazer-Nash Consultancy to research space-based solar power (SBSP) systems. Such systems would use very large satellites to collect solar energy before converting it to high-frequency radio waves and beaming it to ground-based receivers connected to the grid.
The concept, first developed by Russian scientist Konstantin Tsiolkovsky in the 1920s and also featured in the work of science-fiction writer Isaac Asimov, could enable constant solar power. But could the sci-fi idea become reality?
The list of challenges is far from short. Power transmission is one, although a team at the Japan Aerospace Exploration Agency has reportedly designed and demonstrated an orbital system for the conversion of electricity into electromagnetic waves.
Size is another – Earth-based solar farms are huge, some covering the area of more than 1,000 football pitches. SBSP systems would have to be enormous to maximise their lifetime efficiency, bringing manufacturing and deployment challenges that could involve robotic assembly.
Conventional solar cells are also very heavy and therefore unsuitable for launch into space, says Dr Amanda Hughes from the University of Liverpool, who is working with colleagues to research the use of thin-film solar cells instead.
Unlike traditional solar panels, thin-film cells are light, thin, and even offer a degree of flexibility. The Liverpool project, which is not linked to the government scheme, hopes to print them onto solar sails made of materials such as Mylar and Kapton, which harness photon energy for movement.
Ultimately the cells would be placed on lightweight origami-style scaffolds. The frames would be folded to fit into compact cargo holds, before unfolding once released into orbit.
The government hopes that an SBSP system could be deployed by 2050. Frazer-Nash is studying leading international designs and will draw up the engineering plan. It will also compare space-based solar to other renewable sources, while Oxford Economics will help work out the cost.
Such an ambitious project will not come cheap. While the price of associated technology such as rocket launches is falling each year, a significant amount will be needed for R&D, manufacturing and deployment.
The potential benefits are enormous, however. According to an online article by Hughes, a proposed Chinese system known as Omega could supply 2GW at peak – more than could be delivered by 6m conventional panels. As the population grows and energy demand soars, figures like that could be very tempting.
Interest is high even though the cost of conventional solar power has fallen, says Hughes. “The price of silicon has come down significantly but the market has plateaued somewhat. We haven’t seen much increase in efficiency, at least at commercial level.”
She adds: “There have been huge advances in the field of lightweight flexible solar cells in recent years. These efforts have not only been for the benefit of space-based applications – there are plenty of uses for them here on Earth too, such as wearable solar cells on fabrics.”
Space-based solar power stations might be a long shot, but they could bring significant benefits back down on Earth.
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