Because.... in the ensuing years, surely technology will develop to the point that we LATER could send a mission that will arrive BEFORE the previous mission, due to better propulsion technologies. Plus we could send more people, bigger ships, better equipment, etc etc.
Kind of like like heading out to cross the the ocean in a canoe when you know that in a few days ocean liner will be available.
Kind of like like heading out to cross the the ocean in a canoe when you know that in a few days ocean liner will be available.