I've tried writing science fiction before but I always fell out of love with the story. It may not happen with this one but you never know.
That happens to all writers. Don't let it discourage you. Just push your way through it. Or just stop writing that scene and move on to one that you're more excited about. You can always finish the scene later. It may be one you pull once you get to the final edit anyway. The key is to get the rough draft done. Once you have the rough draft, you can polish and edit and massage the story just the way you like it.