A simple solutuion for Terraforming Mars.
Lob jupiters moon Eruopa at it for a impact event, this will provide it with more water and mass, and would likely reactivate plate techtonics on mars. Next lob IO at mars, but into orbit, to become a stablising moon.
Wait a few hundred years for the surface to soldify again and wala, a half baked earth like world!
Easy as pie
