Space units are a special class of units in Civilization: Call to Power. The game introduces a space level on top of the terrestrial level, as well as units that are capable of launching into space and engaging in space combat.
Some units can only be built in space and cannot move down to the terrestrial level. Players are also able to build colonies in space.
Note that while the movement of space units (except Space Planes and Space Fighters) may seem low, it costs only 1/20 of a movement point (i.e. 0.05 MP) to cross each tile in space. Hence the Space Bomber's 2 movement points is actually 40 tiles.