For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Satan the accuser before the throne still in heaven until the big battle with Michael in the book of revelation.
Satan is still in heaven accusing the brethren day and night. He will fall from heaven like lightning at the beginning of the tribulation.
Second Thessalonians 2:3-4 The falling away is the rapture of the church. Apostasia. Means departure from earth to heaven. Then the Son of perdition shall be revealed. Satan himself will fall from heaven like lightning.