The History of Solar Sails
When you say Solar Sails you might be tempted to think about the giant pirate ships from Treasure Planet flying through space looking for treasure and having skirmishes with the Royal Navy. You would be forgiven to think so because it sounds like something out of a space fantasy but its quickly becoming a real thing. What’s even cooler is that this technology has been theorized about since the 1600’s and we’re finally beginning to see the technology beginning to work as intended. So where does this idea come from and how has it progressed, lets find out.
The Birth of Solar Sailing
The Idea for solar sails comes from the legendary Dutch astronomer Johannes Kepler. If that name sounds familiar its because he was the man that figured out 3 major laws of planetary motion which figured out how planets move in regards to other celestial bodies. It’s these same laws that we use to map out the satellites that we send to space today. This is really impressive considering it was just 50 years before he was born that Copernicus figured out the Earth revolves around the earth.
It’s safe to say that Kepler is a really important guy so when he says something you take note of it. So when he was watching the comets fly over the night sky he made a curious observation; comets have tails. He theorized that there must be some sort of solar breeze that caused these tails. In a letter to Galileo Galilei he writes about how humans might use these winds and sail technology to traverse the universe on day.
“Provide ships or sails adapted to the heavenly breezes, and there will be some who will brave even that void.”
I guess you can’t win them all. Even though the idea wasn’t right, it wasn’t completely wrong.
A century later in Britain there was a Scottish man by the name of James Clerk Maxwell. James Maxwell is known as the father of modern physics and comes up with the theory of electromagnetic radiation.
So what does the theory of electromagnetic radiation and solar sails have to do with each other?
Well essentially he finds that photons are little packets of energy released from the sun. This means that sunlight exerts pressure on objects, exactly like wind but with less force. This means that if the sail is big enough we could use it as a method of propulsion in the vacuum of space much like a boat uses the wind it catches in its sails.
A Little Fiction
But that idea hadn’t been caught on yet. It would take the work of an writer/engineer Carl Wiley at the beginning of the space age. In May 1951 Carl published a story in Astounding Science Fiction about a spacecraft pulled by a sail.
In the story Wiley envisions a spacecraft that is tethered to a sail that is pointed away from the sun pulling the spacecraft along as it uses light as the “wind” to push it forward. The idea was so crazy at the time that he published it under the name Russell Saunders, probably to avoid being ridiculed.
Six years later in 1957 the Soviets launched Sputnik and the Americans weren’t having any of that. In response the United States began to pump a lot of money into Space to gain a military and political advantage over their rival. So much money was spent in fact that they began to consider ideas that might have been called crazy a decade ago.
One of these ideas was the solar sail. In 1975 NASA created a prototype of the first solar sail to visit Haley’s Comet. The next year the legendary Carl Sagan went on the Today Show to show off the model that might one day be launched into space.
Although it never was it did make it to Haley’s comet because the technological ambitions were too much too fast and the comet had passed by then the idea found new light in the Planetary Society. The Planetary Society is a non-profit that is dedicated to the exploration of space and understanding our place within it.
Crashing and Burning
Under the Planetary Society the idea of a solar sail that could fly into deep space farther than we have ever been. But before we get to there we’re going to have to go through the burning pile of failures, literally.
In 2005 the Cosmos 1 (the first privately funded Space Sail) launched with the hopes of exploring space but its hopes were squashed when the mission came crashing down, literally. The former Russian ballistic missile, the Volna, that once carried nuclear warheads was carrying the Cosmos 1 but never made it into orbit as its systems failed and it fell into the ocean.
With that failure the Planetary Society had to start over again and began working on the Light Sail, the next generation of solar sails. But by now it wasn’t only the Planetary Society that had seen the potential in solar sailing though. The Japanese Space Program(JAXA- Japanese Aerospace Exploration Agency) was beginning to dabble with solar sails as well.
In 2010 JAXA became the first entity to successfully use a solar sail with the IKAROS with a mission to enter Venus’s orbit and fly around the sun. Although it didn’t enter the orbit the first time around it showcased that like Wiley had predicted, and Kepler had prophesized we could use the sun to propel us around and out of the galaxy.
Solar Sails Today
Solar Sails are seeing a new wave of enthusiasm today because of new CubeSat technology. CubeSat’s are small satellites the size of a loaf of bread that are full of technology that once could only be fit on two ton satellites. With this shrinkage in weight it is possible to use these solar sails to propel us out of the solar system for the first time into other galaxies.
It’ll be interesting to see where solar sails go from here and where they will lead us in the future.
The story of LightSail, Part 1. (n.d.). Retrieved February 10, 2021, from https://www.planetary.org/sci-tech/the-story-of-lightsail-part-1
Howell, E. (2014, May 08). Ikaros: First successful solar sail. Retrieved February 11, 2021, from https://www.space.com/25800-ikaros-solar-sail.html
What is Solar Sailing? (n.d.). Retrieved February 10, 2021, from https://www.planetary.org/articles/what-is-solar-sailing
A brief history of solar sails. (n.d.). Retrieved February 10, 2021, from https://science.nasa.gov/science-news/science-at-nasa/2008/31jul_solarsails