(a) Calculate how much walk is required to launch a spacecraft of mass m from the surface of the earth (mass m/E, radius REJ and place it is a circular low earth orbit-that is, an orbit whose altitude above the earth's surface is much less than RE• (As an example, the International Space Station is oil low earth orbit at an altitude of about 400 k/n, much less than RE = 6380 k/n.) You can ignore the kinetic energy that the spacecraft has on the ground due to the earth's rotation.
(b) Calcn1ate the minimum amount of additional work required to move the spacecraft from low earth orbit to a very great distance from the earth. You can ignore the gravitational effects of the sun, the moon, and the other planets. (c) Justify the statement: "In terms of energy, low earth orbit is halfway to the edge of the universe."