As we know that for the earth and satellite system,

$$\begin{gathered} \mathrm{Kinetic} \mathrm{energy}, \mathrm{K} = \frac{\mathrm{GMm}}{2\mathrm{a}} \\ \mathrm{Potential} \mathrm{energy}, \mathrm{V} = - \frac{\mathrm{GMm}}{\mathrm{a}} \\ \mathrm{and} \mathrm{total} \mathrm{energy}, \mathrm{E} = - \frac{\mathrm{GMm}}{2\mathrm{a}} \end{gathered}$$

where, a = radius of the orbit of the satellite and m = mass of the satellite

On the basis of above three expressions for the energies, we have

$\mathrm{K} = \frac{\mathrm{GMm}}{2\mathrm{a}} = - \left(- \frac{{\displaystyle \frac{\mathrm{GMn}}{\mathrm{a}}}}{2}\right) = - \frac{\mathrm{V}}{2}$