Space Based Solar Power Stations by 2030(Computerworld | Mar 30, 2015)
The first solar energy cell was developed back in 1883, while writer Isaac Asimov published a 1941 story, Reason, describing a space station beaming down vast amounts of solar energy using microwave beams.
US scientist Peter Glaser drew up plans in 1968 to make Asimov's dreams a reality, only to be stymied by the technological limitations of the time.
Japan’s Shimizu Corporation proposes an even more startling SBSP alternative – a 400km-wide belt of solar cells around the Moon's 11,000 km equator. Dubbed the Luna Ring, it could beam back enough energy to meet the world’s energy needs in a heartbeat.
Both China and Japan are planning space-based solar power (SBSP) stations by 2030 that will dwarf previous projects of this kind. “An economically viable space power station would be really huge, with the total area of the solar panels reaching 5 to 6 square kilometers,” explains Wang Xiji from the Chinese Academy of Sciences.
But why build power stations in space?
A major reason is to tap the far higher levels of solar radiation available in space – more than 60% of the sun's energy is lost due to reflection and absorption in the Earth's atmosphere – and do it around-the-clock.
“Space-based solar panels can generate ten times as much electricity per unit area, as produced by ground based panels” points out Chinese space engineer, Duan Baoyan.
SBSP poses huge challenges, in particular the need to ensure super-accurate transmission to avoid frying vast swathes of the Earth’s surface with an immensely powerful wandering beam.
“When transmitting power by microwaves, a significant challenge is how to transmit it with pinpoint accuracy to a receiving site on the ground. Transmitting microwaves from an altitude of 36,000 km to a flat surface 3 km in diameter will be like threading a needle,” says Yasuyuki Fukumuro of Japan's JAXA space agency.
Other challenges are system maintenance in the hostile environment of space and getting SBSP stations into orbit. A commercially viable space power station would likely weigh over 10,000 tonnes – yet few rockets today can carry payloads over 100 tonnes.
While creating SBSP stations poses huge challenges, they echo those faced by mankind's first ventures into space in the 1960s. Many queried the point of putting humans into space at all, and yet the technological and knowledge bonanza from meeting the challenges involved, continues to reverberate through our modern world.