 " Day of the Moon " is the second episode of the sixth series of the British science fiction television series Doctor Who . Written by show runner Steven Moffat , and directed by Toby Haynes , the episode was first broadcast on 30 April 2011 on BBC One in the United Kingdom and on BBC America in the United States . The episode is the second of a two @-@ part story that began with " The Impossible Astronaut " . 
