Nevermind - I thought I had to lead the laser ahead of the planetary body because it was moving. But you just have to aim right at it and hit fire, and it works lol.
There seems to be a bug with the registry. Sometimes when I start the game all the entries are there, sometimes it's just the entry for the sun with no drop down menu, so nothing else appears, and the search function doesn't work either (like I'll search for mars but it says 'no entry found for mars'). And why are the coordinates in this game written backwards?