Out of that almost-tragic decision came a moment of great beauty - an alien bursting out of the fragments of the moon and laying another egg in its place. Unlike the Daleks or Cybermen, this creature did not mean them any harm. It was this realisation that allowed humanity to embrace the search for new and alien worlds once more. The Doctor noted rather jovially (for his character) that looking up at this alien creature above them, humanity began to explore space, stretching out to become the mighty empire presented in every story from Frontier In Space to New Earth. There would be many stumbling blocks along the way - the events of Waters Of Mars take place just one decade later - but it was the moment when humanity embraced the stars once more. Kill The Moon established the moment humanity stopped being scared of the 'threat' of alien life and began to seek it out. That was a very important turning point in the humanity of the future the show has presented.