I wonder how many millennia it will be before we can trivially terraform one of these from another planet for fun. Just deploy a hoard of self-replicating auton

I wonder how many millennia it will be before we can trivially terraform one of these from another planet for fun. Just deploy a hoard of self-replicating autonomous robots and sit back for ten years. Might need some carefully-orchestrated nuclear detonations to increase the average gravitational potential, though.