I know this would be tough and take a long time but we could have 2 extra planets with enough work. 1. Bombarded mars with junk (everything from the astroid be

I know this would be tough and take a long time but we could have 2 extra planets with enough work. 1. Bombarded mars with junk (everything from the astroid belt and some rocks from the kuipler belt) to raise its mass to somewhat earth level. We'd have to be careful not to mess up Mars's orbit too much. 2. Slurp some of venus's thick atmosphere into a massive space tanker 3. Dump the atmosphere onto Mars++ 4. Let time and some engineered bacteria/plants clean up the mess That's my long term goal if I become immortal.