Once you have chosen your asteroid, your spaceship lands somewhere on its surface. Each asteroid consists of three levels - the surface and two subterranean levels. Each level has 100 squares on a 10x10 grid. The asteroids have three terrain types - normal terrain, mine sites denoted by a diamond, and rough terrain denoted by a group of carats. Rough terrain cannot be developed.
Mines extend for two levels and provide the bridge to developing the subterranean levels.
Like most businesses, mining colonies require a delicate balance between maintaining low expenses and keeping your workers happy. You must make your initial million credits last until you begin to successfully mine and sell your ore. You must provide power, living quarters, food, air, medical facilities, ore storage, space ports to facilitate bulk sales, ore processing plants, and, of course, build mines. In addition you must beware of natural disasters and spaceport crashes. This is a daunting task, especially at the more difficult levels where income is limited by the scarcity of mines.