im thinking part of your question is missing
it isnt a wedding without a groom, its an overly elaborate birthday party
now, if you mean you want to get married but your groom is in a space station orbiting the earth and wont be on this planet for another 3 months or something? (thinking of that russian chick who had to do that in case anyone is wondering...) you have to look into the laws where you live, and see if a proxy wedding is an option. even then, wouldnt it be more meaningful if you just waited till all parties involved could be in the same place at the same time?