A spacecraft of constant mass m is in orbit about the Sun. It deploys a perfectly reflecting flat solar sail and controls it so that it is always normal to the radius vector from the Sun (see Figure 1). The acceleration due to solar radiation pressure is then 2SA r cm r3 where S is the solar intensity at 1 AU from the Sun, A is the sail area, and c is the speed of light in vacuum. c) In one of the cases, the spacecraft always escapes. Show that, for all escape trajectories, the hyperbolic excess speed v is 2 2SA v = 0 - / (-5A), 18 cm where ro and vo are respectively the radius and speed when the solar sail is deployed. Please show all steps in your solution for full credit. Sun ag m Figure 1: Solar sail.