"and later we will have to try and determine where on the surface we can have a touchdown"
...which didn't work out too well with Philae, though that may have turned out for the best.
However, even thinking about working out the best place for an impact not part of the original mission plan, long after the mission was supposed to have ended, rather a long way from Earth...rocket science really ought to get more public attention, because it's come an awfully long way from Lunar landings.