Watt’s Happening: Space Energy

Don Pettit


Can’t help myself. I’m a space buff.

That image of the world’s first orbiting space satellite, Russia’s famous Sputnik, as it appeared in Time magazine when I was a kid, somehow became permanently imprinted on my psyche. Space has been an unwavering passion ever since. So my youth was filled with telescopes, chemistry labs and amateur rocketry (which I somehow survived with all fingers and eyes intact).

More recently I have been inspired by several real-life space explorers: Canadian astronaut Chris Hadfield of course, but also a US astronaut who shares my name: Don Pettit. While in my life path I chose a career in the visual arts but maintained a keen interest in space, the other Don Pettit chose space technology as a career and kept photography as a passion. His stunning photos of our planet taken from the International Space Station have inspired millions.

But this is supposed to be a column about energy, right? Let me explain the connection.


The German physicist Max Planck received the 1918 Nobel Prize for his revolutionary quantum theory, a theory that Einstein then used to explain why some metal surfaces emit negatively charged particles (electrons) when struck by light. This mysterious phenomenon had been observed some years earlier and dubbed “the photoelectric effect”, but never explained. Einstein was awarded the 1921 Nobel Prize for his quantum explanation of the photoelectric effect, and not for his theory of relativity.

It took awhile to figure out how to use the photoelectric effect to create a practical means of generating solid-state electricity from sunlight. One of the first applications of solar electricity turned out to be, you guessed it, in outer space.

Pretty well all of the some 20,000 satellites presently orbiting the Earth are solar powered. The International Space Station is the crowning achievement of space-based solar electricity. Its eight massive solar arrays, totaling some 3000 square meters, generate 246 kilowatts of electricity, automatically rotate to track the sun, and keep everything on the ISS working and everybody on board comfortable and safe.

Why would solar electricity be chosen to power the multi-trillion dollar spaced-based communications, exploration and research industry? Reliability: no moving parts to wear out or replace. Safety: no fuel to run out or explode. Unlimited power source: as long as the sun keeps shining, space electricity is there for the taking.


NASA’s Dawn spacecraft just left the asteroid Vesta, having traveled several hundred million miles to get there. It too is powered entirely by the sun. A revolutionary solar-electric propulsion system takes electrons generated by solar panels and uses them to bombard a tiny bit of xenon fuel, then accelerates the resulting charged particles with an electric field. The resulting jet of ions creates a small but continuous thrust, which over the months of a deep space voyage can build up immense velocities.

Likewise, NASA’S new asteroid capture mission, launching in the next few years, will use a 40 kilowatt solar array to power its solar-electric propulsion system. After rendezvousing with a small asteroid, it will capture it and haul it back to lunar orbit for study. Understanding asteroids will help us figure out how to divert an inevitable Earth-threatening asteroid like the kind that wiped out the dinosaurs. Thanks to solar-electric power and propulsion, the door to our solar system stands wide open.


Happily, all the advantages of solar power (reliability, safety and a forever fuel source) have come down to Earth over the last couple of decades in the form of inexpensive and readily available photovoltaic panels. Why does it feel so cool to power my home and business with space energy? Perhaps it’s a little bit of the other Don Pettit coming through.

Don Pettit is an author and photographer from Dawson Creek. He is a founding member of the Peace Energy Cooperative, a renewable energy cooperative out of Dawson Creek.