bungie should add the entirety of earth. (they could do the others later, but earth first.) not only does it do a majorly sensible thing (why the hell are we fighting on mars when we are holding onto earth with one finger) it gives us a reason to use our ships. summon ghost, press some 3rd button, and hop in the ship to fly towards england, america, india, etc. possibly fight the skiffs, tombships, etc. on the way also gives a reason to have the different ships as now they'd be upgradeable like a player, maybe? talk to the shipwright to acquire different kinds of guns, thrusters, and things like heatseekers ships naturally have different stats, but ofc a green ship wont outdo a blue just shooting it out there if nobody's already said it