I'd like to think that the "co-ordinates" for Earth were in Navigational computers and the like, so 'bots didn't need to know them. That way it was easy for the information to be wiped from nav computer data banks.
Bit like GPS for us: we can type a location into a Garmin which will then tell us how to drive to it. We don't need to know (or remember) the exact lat/long co-ordinates.
Ark Navigational Main Menu -> Recent destinations -> Earth -> Engage!
Space flight = cakewalk.
:D