Of all the shiny things we’ve sent into space, this has got to be one of the coolest.
The Planetary Society, a nonprofit dedicated to exploring our solar system, will be launching the Prox-1 CubeSat on June 24, via SpaceX's Falcon Heavy rocket. The Prox-1 will be carrying the crowd-funded craft, LightSail 2.
Things will get interesting about two weeks after launch when Prox-1 will deploy its sail, which will slowly take LightSail 2 into orbit by using the pressure from solar photons. Meaning, the craft will be fueled solely by—that’s right—sunlight.
If the 32-square-meter sail works as planned, it will be the first entirely solar-powered spacecraft to fly in Earth's orbit. Keeping it there will also prove that solar sails like this will be able to fly more CubeSats in the future.
LightSail 2 will be inside Prox-1 during liftoff and remain there until the rocket drops it off to circle Earth for a week. The magic will happen at the end of that seven-day period, when Prox-1’s P-POD, (the front door of the CubeSat dispenser), will open and use a spring to push LightSail 2 out into microgravity.
Once in space, LightSail 2 is expected to start functioning right away. It will automatically boot itself up, get its antenna going and beam health and status updates back to Earth. Its solar panels will be released about 5 days after deployment from Prox-1, also revealing the triangular solar sail sections that will have been hiding out in storage compartments until then.
It will be about two weeks after launch before the team on Earth will send a message to LightSail 2 to fly on its own.
From that point, LightSail 2 will be afloat on a sea of solar photons, using its momentum wheel to adjust itself when it starts floating toward or away from the sun. When heading in the direction of our star, the sail will turn off its thrust, then turn it back on when flying further away. Photon pressure gives a very slight push, but it will continue to propel the sail halfway around Earth.
Then comes the real sci-fi part. To get an idea of where LightSail 2 is and if it's getting into orbit as planned, the Planetary Society has joined forces with the International Laser Ranging Service (ILRS). The ILRS will use a network of ground-based lasers to reflect off the cluster of mirrors on the outside of the craft. That reflection time will tell us if the sail is where it's supposed to be.
While LightSail 2 will not be able to keep up its orbit forever and eventually burn up in the atmosphere, it will be visible from terra firma after the solar sail deploys, so you may be able to see it will be flying over your head from the comfort of our home planet.
(via The Planetary Society)