Q Could we harness energy in space for use on Earth?

— Arielle Howard

A Dan Ludois, professor of electrical and computer engineering at the University of Wisconsin-Madison:

In regard to collecting energy from a source in space, the natural answer is the sun.

The sun is a giant fusion reactor that powers our solar system, and harnessing its radiation is the first step.

To collect the solar radiation, you could use solar panels that convert the sun’s radiation into electricity. You then have to take that electricity and somehow send it down to the Earth.

Researchers are currently looking into this topic, and the popular idea is to use microwaves to beam that electricity down to Earth.

The entire process requires a number of steps: 1) gather radiation from the sun; 2) turn the radiation into electricity; 3) turn that electricity into microwaves; 4) beam the microwaves down to Earth; 5) turn the microwaves back into electricity that we could use.

People can, and do, use solar panels on the Earth to collect the sun’s radiation. The question is: What are the benefits of collecting this energy up in space?

On Earth we have day and night due to the rotation of the planet. Up in space you could position a satellite in a location where it’s getting the sun all the time.

Also, our planet has an atmosphere that filters some of the sun out, so not all of the solar radiation makes it down to the Earth. By putting solar panels up in space, you could potentially capture much more energy.

The downside is that a vast array of solar panels and equipment conversion systems are needed both up in orbit and down on the ground. It’s extremely expensive to put something up in space.

The idea of harnessing energy in space for use on Earth is very technically feasible, but the engineering challenges and economics are daunting for it to be practical.