They attempt to make Mars habitable by pummeling it with comets in an attempt to deliver Mars with water, methane, etc. The pummeling also heats up the planet.
They retrieve the comets from the kuiper belt using gravitation towing. The towing is done by probes or piloted by humans, your choice.
Something goes wrong. A Comet heads toward Earth or towards the habitation zone on Mars. Or a whole of comets get disturbed due to the slightly chaotic nature of the solar system.
Also, the pilot is a women or an android or both.
They attempt to make Mars habitable by pummeling it with comets in an attempt to deliver Mars with water, methane, etc. The pummeling also heats up the planet. They retrieve the comets from the kuiper belt using gravitation towing. The towing is done by probes or piloted by humans, your choice. Something goes wrong. A Comet heads toward Earth or towards the habitation zone on Mars. Or a whole of comets get disturbed due to the slightly chaotic nature of the solar system. Also, the pilot is a women or an android or both.