Joseph Fielding Smith writes that man will be limited to this earth; does not believe man will ever have "dominions beyond this earth while they dwell in mortality."
Joseph Fielding Smith, Answers to Gospel Questions, 5 vols. (Salt Lake City: Deseret Book, 1958), 2:191-92
MAN IS LIMITED TO HIS OWN EARTH
When man was placed on this earth it became his probationary or mortal home. Here he is destined to stay until his earth-life is completed, subject to all the mortal conditions outlined in the beginning. There is no prophecy or edict ever given that mortals should seek dominions beyond this earth while they dwell in mortality. Here we are, and here we should be content to stay. All this talk about space travel and the visiting of other worlds brings to mind vividly an attempt long ago made by foolish men who tried to build to heaven.
The earth is our destined earth home. With this in mind, wise men will be content and will wait until the time comes when this earth is cleansed and purified from all sin for heavenly visits, and in that day they will come.