Comment by jadell

It's not necessarily one way. Think of it like a sailboat: wind blows in one direction (at a time) but you can still steer, change direction, speed up, slow down, etc. just by changing the angle of your sail and how tense or slack it is. You can even travel against the direction of the wind. This is the same concept - a sail in wind - except the wind is solar wind: a stream of photons. The difference being that in sailing, the resistance of the water plays a part. For solar sails, you can't do as many complicated maneuvers as with sailing on water, but you can still make adjustments beyond juts being pushed in a single direction.