a hangglider steers by weight shift. to over-simplify, the pilot moves the body weight in relation to the balance point of the wing, inducing a lateral force, that turns the craft. this soon to be launched NASA NEA Scout probe is powered by a solar sail that catches the sun’s photons. in order to steer a course other than away from the sun, the craft will move its center of gravity in relation to the sail very similar to hangglider weight shift. because, physics.