Therefore, its known narrative elements are not a part of the Doctor Who universe. It may have been the basis for a similar story in another medium, however — and that story may indeed be a part of the DWU.
Mission to Magnus was an unproduced story for the original Season 23.
Basic plot Edit
Philip Martin, the writer, came up with the scheme while his wife worked at the University of Lancaster. He told a group of intellectuals that he was writing for Doctor Who and asked if he wanted to make the Earth drastically colder, how would he do it? The group replied that you would have to change the tilt of the axis of the Earth and told him a specific way to do it. He worked this into the script.
The story would have focused on the Ice Warriors, who would have tried to change the tilt of Magnus to better suit themselves. They would betray Sil, but the Doctor would have stopped them with their own technology. (DOC: The Lost Season)