Solar Space Power
Written by Fraser Cain
Solar space power satellite.
On average, the hits the Earth's surface with 341 watts of energy for every square meter of the planet. That doesn't sound like much, but keep in mind that that's averaged, and includes night and planet's poles. In fact, the Earth's atmosphere is blocking a lot of that energy. If you could launch satellites to gather solar space energy, you would be able to get upwards of 5 kilowatts of energy per square meter.
This sounds like science fiction, but Japanese engineers are currently working on a program that would launch a spacecraft to geostationary orbit. Once there, it would collect vast amounts of solar space power and then beam it down to a transfer station on Earth. By 2030, they're hoping to launch a spacecraft that would generate 1 gigawatt of solar space energy – the same as a large power plant.
The US government is also considering a solar space power system. The Pentagon recently released a report that recommended a pilot solar power station be sent into orbit to test if energy from space can be safely beamed back down to Earth and then converted into electricity. A prototype spacecraft like this might cost $10 billion USD.
All the space solar systems follow the same basic structure. A huge array of solar panels would be launched into orbit around the Earth and collect energy from the Sun. This energy would be concentrated and used to power a microwave beam that would transmit the energy down to Earth. A collection facility would be able to capture the energy and turn it into electricity again.
There are obvious safety risks from having a huge microwave beam striking the Earth. And the costs of launching an maintaining the solar satellites will be enormous. But it might just be the idea that keeps our energy hungry economies going after the fossil fuels run out.
Here's an article from Universe Today that looks into the idea of harvesting power from space.
Scientific American has a great article about space-based power development.
We have recorded an episode of Astronomy Cast just about the Sun called The Sun, Spots and All.
Filed under: Astronomy
