Near the landing site of the Apollo 11 mission, a stainless steel plate reads "Here men from the planet Earth first set foot on the moon, we came in peace for all mankind."
Although space travel can be a dangerous, intensely stressful enterprise, astronauts have done very well to live up to that message of peace. Granted, we haven't met anyone to fight with on these missions, but people can get pretty tired of each other when you put them together in a cramped spacecraft.
So there's something to be said for the fact that until now, nobody has been accused of any criminal activity that took place outside of the earth's atmosphere.
Not only that, but we're still in the early stages of determining whether a crime took place even in the case we're about to look at.
