# Energy of an Orbiting Satellite

The kinetic energy of the satellite in a circular orbit with speed 'u' is

Considering the gravitational potential energy at infinity to be zero, the potential energy at distance (R + h) from the center of the earth is

. The K.E is positive whereas the P.E is negative. However, in magnitude the K.E is half the P.E, so the total energy is E = K.E + P.E =. The total energy of an circularly orbiting satellite is thus negative, with the potential energy being negative but twice is magnitude of the positive kinetic energy. When the orbit of a satellite becomes elliptic, both the K.E and P.E vary from point to point. The total energy, which remains constant, is negative as in the circular orbit case. This is what we expect, since as we have discussed before if the total energy is positive or zero, the object escapes to infinity. Satellites are always at finite distance from the earth and hence their energies cannot be positive or zero.

The total energy of an circularly orbiting satellite is thus negative, with the potential energy being negative but twice is magnitude of the positive kinetic energy. When the orbit of a satellite becomes elliptic, both the K.E and P.E vary from point to point.

The total energy, which remains constant, is negative as in the circular orbit case. This is what we expect, since as we have discussed before if the total energy is positive or zero, the object escapes to infinity. Satellites are always at finite distance from the earth and hence their energies cannot be positive or zero.