[cornholio]

Terraforming is an exceptionally energetic endeavor. Even if you had the perfect combination of icy asteroids with just the right amount of water, nitrogen, oxigen etc. and the means to hurl them towards Mars, this kinetic event would be so energetic that it would take centuries to millennia before the surface would cool to habitable temperatures. it's not physically possible to do it ex in the span of a human lifetime.

Ar the scale terraforming entails, the crust reactions with the new atmosphere are closer to a rounding error.

[lisper]

Just put a parachute on the asteroid.

;-)

[cornholio]

All that kinetic energy needs to go somewhere. It's irrelevant if the asteroid burns up in the atmosphere or if trillions of tiny parachutes heat the atmosphere.

I guess you could devise some scheme where kinetic energy is shed or transformed into useful tasks; for example, delivering to Venus an amount of water similar to Earth requires an icy ball half the diameter of the Moon - and the kinetic energy of this mass traveling at 10km/s is about half of the energy required to spin up Venus to a 24h cycle. So some space elevator like contraptions could hypothetically catch the snowballs and lay them on the surface while at the same time spinning up the planet.

But if you have the required clarketech it's unclear why bother with planets instead of creating exponentially larger and better habitats.

[lisper]

You must have missed the smiley emoticon. Yes, I am well aware that parachutes on asteroids won't work. It was a joke. (I used to work for NASA.)