There are no defenseless children in “Alien: Earth.” Quite the opposite. With “Alien: Earth,” he has a broader canon to play with, one with plenty of unclaimed space. In these first episodes, “Alien: Earth” makes a stellar effort to conquer that mission. Corporate inhumanity is a core feature of the “Alien” movies, but “Alien: Earth” uses a variety of faces to illustrate it. Between this and the three corporate players we have yet to meet, “Alien: Earth” can go in assorted directions from here, which is an exciting thought.