We're adding metal to the mix.
Mars is rich in metals and we'll be shipping them back to a metal hungry Earth.
To carry our first load of metal, I've added a new ship called 'Pebble' which will be unlocked when Mars develops far enough.
Mars ships are supposed to be chunky and robotic looking, as opposed the Earth ships that are based off sea creatures.
Starting with a sketch:
Into the Blender:
And out comes Pebble:
Finally, the first drafts of Triton and Mercury are also done, giving us a more complete Solar System: