 What is the landscape of Ganymede like?
The glowing semi-disk of Jupiter was more than half a million miles distant. Maybe they live soft back on Earth since the mines and the Jovian satellite colonies grew; but they were out here in the beginning, most of them. Sometimes there's no reason but them for sending a ship back with a crew instead of in an economy orbit. Then he headed the tractor across the frozen surface of Ganymede toward the permanent domes of the city. "Ganymede's only about the size of Mercury, something like 3200 miles in diameter, so things get heaped up at steep angles. In the gravity of Ganymede, the man was knocked off balance as much as he was hurt, and sprawled on the floor.
 Frozen, cold, and dim
 Steaming hot and rugged  Riddled with volcanic puffballs  Frozen, cold, and dim  Steep mountains of rock and ice