This Age of Steam Expansion expands the game to Mars. Age of Steam Expansion - Mars: Global Surveyor is an expansion for the basic game Age of Steam. The originality of this expansion is that the green discs (the Martians) can move around the planet, and birth with blue cubes. The map uses the same mechanic as Age of Steam on the Moon and allows edges connections. This expansion is sold on the back of the reprint Age of Steam Expansion: The Moon, and printed on one large heavy plasticized paper map (52cm x 36cm)