LightSail2 and the Case for Solar Sailing

Two of humanity's biggest challenges exploring, as opposed to observing, deep space are the speed limitations of conventional fuel-based propulsion technologies, and the inherent finite nature of those fuel sources on a spacecraft. As an example, Voyager 1 launched in 1977 and only first reached interstellar space (leaving our solar system) 35 years later in 2012. Voyager 1 is expected to run out of fuel and the means to communicate its findings back to us by around 2025, approximately 48 years after launch.

STP-2 SpaceX Falcon Heavy Launch

Image courtesy of Peter Van Delden

On June 24, 2019, Planetary Society’s LightSail2 launched on a SpaceX Falcon Heavy rocket as part of the U.S. Air Force’s STP-2 mission payload in the Prox-1 carrier spacecraft. The purpose of LightSail2 is to test the ability to propel a spacecraft using nothing more than radiation pressure from the sun (like wind in the sails of a boat). While this solar sail mission will take place entirely in Low Earth Orbit, and only hopes to add approximately 1 KM/day to the satellite’s acceleration, it has far reaching implications for the future of deep space science and exploration.

LIGHTSAIL 2  Artist's concept of LightSail 2 above Earth.  Image courtesy of Josh Spradling / The Planetary Society

LIGHTSAIL 2 Artist's concept of LightSail 2 above Earth.

Image courtesy of Josh Spradling / The Planetary Society

Consider that a spacecraft using conventional space propulsion technologies would take approximately 75,000 years to reach our closest neighboring star system, Alpha Centauri. “Beam sailing” projects like Breakthrough Starshot, already in the planning stages, theorize that interstellar travel at up to 1/5 light speed can be achieved by using high-powered lasers as a power source for light sails. For context, that would reduce the duration of the same trip to Alpha Centauri to 20 years.

Solar sailing is presently in its infancy, but it takes the kind of small steps that Planetary Society, with the help of its global network of members and supporters, is taking with missions like LightSail2 to eventually achieve these kinds of quantum leaps.

This is why we do space science, and BoldlyGo is proud to have been the first mission sponsor of Planetary Society's LightSail2.