To paraphrase (or rip off) H.G. Wells...
Who could have known that at the dawn of the 21st century, from across the vastness of space our red planet was being observed. Intellects vast, cool and unsympathetic studied the myriad comings and goings of our home as carefully as they might observe the organisms that swarm and multiply in the occasional, incredibly rare drop of liquid water that you might find. They looked upon the 4th planet from the Sun, its resources and natural history with envious eyes, and slowly they drew their plans against us.
It started with seeming innocence, with simple observational missions from high above our beloved red deserts. Then the limits of the Outsiders aggression were made clear by the orbital bombardment of our world with BEAGLEs and probes that alledgedly were meant to go into orbit if they had not been programmed with the wrong unit of measurement, but these were just the initial phases of a far more sinister conspiracy......INVASION!!!