Snowball was the first game in the Silicon Dreams trilogy of text adventures developed by Level 9. Released in 1983, it was notable for the intentional ambiguity of the lead character Kim Kimberley's gender, and it's unprecedented number of locations (something of a cheat, as 6800 are near identical) to indicate the monotonous scale of it's setting.
Snowball 9 is a massive starship carrying 1.8 million cryogenically frozen colonists on a century long mission to the planet Eden. The ship is named after the shell of ice which protects it from interstellar debris.
During the final stages of the journey the ships protectors, the robotic Nightingales, are unable to prevent a deranged crew member sabotaging the ship by setting it on a course for Eden's star. Before it's destroyed by the saboteur, the ships computer awakens security agent and player character Kim Kimberley to resolve the emergency.