Siberian students came up with fitting out small space vehicles with solar sails
The students suggest fitting out each satellite with a unified container which after service life expiration automatically spread a solar sail and evoke a natural slow down. By doing so, the satellite will gradually decrease the orbital altitude, enter the atmosphere and burn down. From the other side, the sail can also be used to accelerate a vehicle by catching the pressure of solar lights similar to the working principle of an ordinary sail at windy conditions. In such a way, one could gradually increase an orbital altitude and even move beyond the Earth gravitation field.