Xadomy

Hostile aliens are threatening the planet Earth. There is but one hope. Centuries ago, an uninhabited planet on the dark side of the universe became the base for the only hyponuclear weapon in existence. This weapon can only be activated by a code being entered into the planet's computer. If this weapon is activated, Earth will be saved.

Your mission is to find and enter the code. It can be found in one of the 100 locations on the planet. If you fail in your mission, you will be destroyed and the Earth will be open to attack. Due to the planet being outside time, there is no time limit on your mission.

The planet is: Xadomy.