LightSail 2 has been in area for two years now and may final even longer earlier than diving again into the environment
The Planetary Society’s crowdfunded solar sailing CubeSat, LightSail 2 was launched on June 25, 2019 and two years later the mission is still going strong. LightSail 2 is a breakthrough technology demonstration of solar sailing ability, leveraging the gentle thrust of photons from the sun to maneuver and adjust its orbit. Within a few months of its launch, LightSail 2 was already declared a success, breaking new ground and expanding the possibilities for future propulsion systems for spacecraft. Since then, it has been testing the limits of solar sailing in an ongoing expanded mission.
One of the main objectives of this expanded mission is to try out the spacecraft in different operating modes while learning how to sail efficiently and effectively. Although two years of flying in the harsh orbital environment have started to degrade the sail, software updates, learned experience, and careful debugging efforts have ensured that the LightSail 2 still flies exceptionally well. Shrinkage, wrinkles, and delamination must be continuously monitored, but nonetheless the team reports that the current “orbit decay rates … are the lowest we’ve seen since the early days of the mission”.
Of course, it will deorbitize at some point. The spacecraft is now at an average altitude of 692 km (about 25 km lower than its original orbit). In sailing mode he loses less than 20 m per day and even gains altitude on good days. When you’re not sailing, the LightSail falls about 50m per day.
It is clear that the mission was an amazing success, and the Planetary Society is not afraid to share its findings. The LightSail 2 team regularly posts pictures from orbit, which can be seen here.
LightSail 2 over the Bahamas. Credit: the Planetary Society.
It was a long way to get to this point. Even if you don’t know the Planetary Society’s history of solar sailing technology, you can probably guess from the name that LightSail 2 isn’t their first try. The idea was championed early in the company’s history by one of its founders, the famous astrophysicist Carl Sagan. Driven by his passion and influence, a plan was developed that would eventually become Cosmos 1: a 100-kilogram vehicle launched from a submarine on a Russian Volna rocket in 2005. Unfortunately, a launch vehicle failure prevented Cosmos 1 from reaching space.
The Planetary Society didn’t give up. With improvements in satellite technology, smaller, cheaper, toaster-sized CubeSats became viable test vehicles that enabled the formulation of an ambitious new plan, starting with LightSail 1, which launched in 2015. Its orbit turned out to be too low for sunlight pressure to overcome atmospheric drag, but it laid the foundation for LightSail 2, which has now reached leaps and bounds beyond its predecessors.
It is worth noting that solar sails have also been tested outside of low earth orbit. In 2010, the Japanese Space Agency (JAXA) successfully used a solar sail called IKAROS to navigate over the cloud peaks of Venus.
There is still a long way to go, but there is hope that this technology could eventually make interstellar travel possible. Initiatives such as the Breakthrough Starshot program provide solar sails that, powered by concentrated laser light, could transport small probes to nearby stars like Alpha Centauri in an incredibly fast travel time of just 20 years. The lessons of LightSail 2 could be an important first step on the path to distant stars. And right now they’re an inspiring symbol of perseverance and ingenuity (and I don’t mean the Mars robots).
Learn more: https://www.planetary.org/articles/lightsail-2-completes-second-year-in-space