Picture this: You’re traveling through space and see a spacecraft cruising by, but rather than being propelled by rockets, it’s mobilized by a large, shiny, tinfoil-like sail.
No fumes, no tail, just a sail propelled by sunlight — a propulsion system scientists believe could push the boundaries of space exploration and interplanetary travel in new ways.
What Are Solar Sails?
A solar sail is a large, reflective surface, usually made from lightweight materials like Mylar or polyimide, that captures light from the sun.
When sunlight strikes a solar sail, photons bounce off, transferring momentum to the sail and pushing the spacecraft forward. Similar to how a sailboat tacks against the wind, solar sails alter a spacecraft’s trajectory and orbit, offering continuous acceleration as long as sunlight is available.
Companies Using Solar Sails
Japan’s Aerospace Exploration Agency (JAXA) was the first to use a solar sail to propel its IKAROS spacecraft in 2010.
Planetary Society’s LightSail 1 and LightSail 2 — both launched in 2019 — showed low Earth solar sailing was possible.
Additionally, NASA’s upcoming Advanced Composite Solar Sail System (ACS3) will test larger sails in Earth orbit, while its 2025 Solar Cruiser mission will deploy a sail the size of over six tennis courts.
The Future of Solar Sails
Solar sails have come a long way since Johannes Kepler illustrated his idea of solar sailing in the 1600s.
Today, solar sails are being proposed for critical roles like solar monitoring and flybys of multiple celestial objects. They’ve even been touted as the future of CubeSat propulsion, helping these small, low-cost satellites operate in space without traditional rocket fuel.
In the future, a hybrid propulsion system that can propel solar sails further into space with the help of ground-based lasers may be implemented.
Image Credit: Shutterstock.com / Love Employee
