[aminok]

There's a way to slow down:

http://www.lunarsail.com/LightSail/rit-1.pdf

>The lightsail is built in two sections, an outer doughtnut- shaped ring, and an inner circular section 30 km in diameter. This 30 km payload section of the sail has a mass of 71 metric tons, including a science payload of 26 metric tons. The remaining, ring-shaped "decel" stage has the mass of 714 metric tons, or ten times the smaller payload "stage". The central payload section of the sail is detached from the larger stage and turned around so that its reflecting surface faces the reflecting surface of the ring-shaped portion (see Fig. 4). At a time 4.3 years earlier, the laser power from the solar system was upgraded to 26 TW (there are 37 years to get ready for this increase in power). The stronger laser beam travels across the space to the larger ring sail. The increased power raises the acceleration of the ring sail to 0.2 m/s2 , and it continues to gain speed. The light reflected from the ring sail is focused onto the smaller sail, now some distance behind. The light rebounds from the 30-km sail, giving it a momentum push opposite to its velocity, and slowing it down. Since the smaller sail is 1/10 the mass of the larger one, its deceleration rate is 2.0 m/s2 , or 0.2 g. The light flux on the smaller sail has increased considerably, but it is only two-thirds of the maximum light flux that the sail can handle.