The LightSail 2 experimental spacecraft from the Planetary Society – designed to fly on light from the sun – has lived up to its namesake. The non-profit today announced that the satellite has successfully increased its orbit around the earth thanks to sunlight that pushes on the large, reflective solar spring of the vehicle. It is the first time that a spacecraft in the Earth's orbit has used solar-powered sailing to change its path around our planet.
LightSail 2 has been in a low orbit above the Earth since its launch on a SpaceX Falcon Heavy rocket on June 25. Last week the spacecraft successfully deployed its sail – a thin, square piece of mylar the size of a boxing ring. Since then, the Planetary Society has been turning and rotating the sail's position in orbit to optimize the spacecraft's ability to utilize the power of the sun's light. And so far this orbital dance has worked. The Planetary Society says that LightSail 2 has raised a part of its trajectory by about 1.7 kilometers, and that this change can only be attributed to solar powered sailing.
"We are excited to explain mission success for LightSail 2," said Bruce Betts, LightSail program manager and chief scientist for the Planetary Society, in a statement.
This demonstration is exactly what the LightSail mission wanted to prove. The Planetary Society, which advocates space travel and funding for space projects, has the LightSail crowdfund to demonstrate that small satellites could only rely on light to propel space. Particles of light have no mass, but they carry speed. And this light can actually push objects in the space. With a large, thin and reflective sail, a spacecraft can capture enough of this momentum from the light of the sun and change its position.
"This idea that you can fly with spacecraft – that you can propel into space – only through photons, is really surprising," said Bill Nye, CEO of the Planetary Society, at a press conference. "And for me it is very romantic that you sail on the sun's rays."
Solar sailing in space is not exactly new. A Japanese spacecraft named IKAROS used a light sail to sail through space on its way to Venus in 2010. The Planetary Society, however, wanted to demonstrate that the same technique could be used for smaller satellites, in particular CubeSats – a type of standardized spacecraft that is usually not much larger than a cereal box. CubeSats have become a great tool for companies, researchers, and more who want to collect data from space using a relatively inexpensive spacecraft that is easy to build.
Small satellites such as these maneuver through space is difficult. Most satellites have to rely on mobile engines – small engines that burn chemical propellants to push a vehicle through space. That can be an expensive addition to a spacecraft, and the propellants required for these thrusters add weight, which is expensive when launching things from the Earth. Small satellites such as CubeSats are usually not suitable for bow thrusters and cannot be maneuvered once they reach space.
Now the Planetary Society has demonstrated that this usable sun shade could be added to CubeSats in the future, giving these mini probes an option to move around the room without using traditional chemical propellants. "We have a very small spacecraft that delivers very high performance, very capable solar-powered sailing," says Nye. And Nye says it took $ 7 million to leave – about a twentieth of the cost it would have been if the organization had done this with an average spacecraft, he claims. The organization says it will share the data it receives from this mission so that other groups may be able to use this technology in the future.
In the meantime, the Planetary Society will continue to run on Sun rays with LightSail 2 in the coming month. "We expect to continue to increase the runway until the end of August," said David Spencer, project manager and associate professor LightSail 2 at Purdue University, during a press conference. Finally, LightSail 2 is withdrawn to earth. The spacecraft is in an elliptical orbit around our planet and every time it cancels its orbit, it dives closer to the earth on the other. The thin LightSail 2 atmosphere will shortly drag down and the vehicle – with its sail – will burn up again on return. But at least it has entered a little before that time.