Reflected light pressure will push against Cosmos 1’s eight reflective blades, designed to adjust to the continuously changing orbital energy and spacecraft velocity. Cosmos 1 will be the first attempt to sail under sunlight pressure.

The laser light from our solar system hits the ring-shaped remainder of the rendezvous sail and is reflected back on the return sail, sending it on its way back to the solar system.

It occurs to me that, since the thrust is provided by photons reflecting off the sail, and since every photon hitting the return sail will have already hit the remains of the other sail, the two thrusts should cancel out. I’m sure they’ve thought it out, but, from what they said there, I really can’t see how the return sail idea is going to work.