Energy of a satellite and escape from the orbit

A satellite of mass $800\mathrm{kg}$ travels on a circular orbit of radius $r=8.0\cdot 10^6\mathrm{m}$ around the Earth ($G{M}_T=3.98\cdot 10^{14}{\mathrm{m}}^3/{\mathrm{s}}^2$). Compute its mechanical energy and the minimum work needed to bring it to infinite distance.