A space shuttle is describing a circular orbit at an altitude of 563 km above the surface...

A space shuttle is describing a circular orbit at an altitude of 563 km above the surface of the earth. As it passes through point A, it fires its engine for a short interval of time to reduce its speed by 152 m/s and begin its descent toward the earth. Determine the angle AOB so that the altitude of the shuttle at point B is 121 km. (Hint, Point A the apogee of the elliptic descent orbit.)