“Sure, your rocket’s reusable, but can it go 300k miles on the original engine?”
perilunar
300k miles is only about 12 low earth orbits, so easily achievable by a second stage booster (though it’s going to be coasting for most of it). Not so easy for a booster though.
bee_rider
Really once the rocket is in space, the joke kinda falls apart; frictionless vacuum and all that.