LightSail 2 Successfully Orbits The World Using Only Solar Energy


The Planetary Society has officially carried out a demonstration that was discussed by Carl Sagan on the Tonight Show with Johnny Carson back in 1976. Carl Sagan talked about a new kind of space propulsion known as solar sailing. The final demonstration took ten years of hard work along with seven million dollars in crowdfunding to make LightSail 2 become the very first spacecraft to rely on solar power for raising its orbit.

Bruce Betts, LightSail program manager and Society’s chief scientist, said, ‘We’re thrilled to announce mission success for LightSail 2. Our criteria was to demonstrate controlled solar sailing in a CubeSat by changing the spacecraft’s orbit using only the light pressure of the Sun, something that’s never been done before.’

The LightSail 2 spacecraft has been in orbit for more than a month, and last week it opened its sails for the first time. During the eight days that have passed since then, the spacecraft has managed to raise its orbit by 1.7 kilometers using only solar power. LightSail 2 follows in the footsteps of IKAROS (from Japan) solar sail becoming the second successful attempt so far at solar flying. However, unlike IKAROS, LightSail 2 can use this technique of propulsion for actually changing its orbit.

As per project manager Dave Spencer, an onboard algorithm is in charge of autonomously controlling LightSail 2. The software twists the spacecraft 90 degrees every fifty minutes thus altering the orientation of the craft. This means that LightSail 2 is able to get energy from the Sun, regardless of where it is. The amazing algorithm is continuously being updated and tweaked. The most challenging aspect of the mission so far has been adjusting the momentum of the spacecraft that is controlled using a spinning wheel.

Bill Nye, the CEO of The Planetary Society, said, ‘We are learning a lot from LightSail 2 right now. In other words, although we’ve declared mission success, and we did this thing that we have been hoping to do for – depending on how you reckon – 42 years, LightSail 2 will fly for almost another year… We are going to learn a lot about controlling the spacecraft and the performance of the sails in the next few months.’

Spencer explained during a press briefing while talking about the upper limit of altitude, ‘The atmospheric density at those altitudes is really poorly modeled and highly variable, and so we don’t really know at what point atmospheric drag is going to overcome our ability to continue orbit raising. So we’ll keep doing this as long as we can.’

Bill Nye also said, ‘This technology enables us to take things to extraordinary destinations in the Solar System and maybe even beyond, in a way that was never possible before, because you don’t need fuel, you don’t need all the systems to control fuel, manage fuel and buy fuel.’