If a satellite is orbiting in space having air and no energy is being supplied, then the path of that satellite would be

Air offers viscous resistance to the motion of satellite. So the satellite loses its energy in over coming this viscous drag.

Now total energy of the system = $-\left(\frac{GMm}{2r}\right)$

Since $-\left(\frac{GMm}{2r}\right)$ is decreasing , r is also decreasing. 

So the satellite with follow a spiral path and finally strike the surface of earth.