What would be an easier way to start terraforming Mars than evaporizing the CO$_2$ deposit near the south pole ?
An autonomous nuclear heating device of about 1000 kg for instance, that landed on that deposit could penetrate it by melting first the water ice coverage and then advance somehow within the evaporating or melting CO$_2$ ice.
According to this article the top water ice layer could be up to 20 meters thick while the underlying CO$_2$ layer would count 300 meters.
If CO$_2$ gas could be produced in this layer, that could even blast away parts of the water ice layer if it is thin enough, uncovering CO$_2$ ice that would sublimate automatically.
Could there be a known way for the heating device to advance in the CO$_2$ deposit ?
For instance, could liquid CO$_2$ be used as a propellant to move the nuclear device somehow ?