re: Why rescue? Colonize from the start!
Then again, they might be just what Mars needs to start making it habitable for us.
Hey, didn't you read the Arthur C. Clarke story? I think it was him. A bunch of
astronauts die on a planet (I think it was Mars) and their bodies provide the
nutrients needed for the plants to survive and eventually change the planet
into something more Earth-like.
Okay, okay - we can ship people already dead to Mars.