The shattered planet is a planet in an unknown star system where the Fortuna ended up.
Description[]
At some point in the past, the planet suffered a cataclysmic event in which the Robots activated an Alien Engine on the planet's surface, shattering it and completely wiping out the inhabitants. At some point after the Fortuna disappeared, it ended up in the asteroid field composed of the planet's remnants.
Twenty years after the Fortuna vanished, while fleeing an attack by the Robots, the children of the Resolute attempted to reach Alpha Centauri with the help of the Robot. Attempting to lock onto Alpha Centauri's radar signature, the Robot instead locked onto the Fortuna's and brought the Jupiter 2 to this star system. The children quickly realized that something was wrong when they saw that the planet only orbited one star instead of the three orbited by Alpha Centauri. After seeing the state of the planet, the children were left wondering what had happened to it before they found the Fortuna floating amongst the asteroids. ("Ninety-Seven")
The children become stranded here for a year after their ship's engine is damaged by an asteroid collison. They discover that while most of the planet is barren and lifeless, the atmosphere having been ripped away by the cataclysm that had destroyed the planet in the first place. However, a single deep valley survived the disaster and is still habitable. There, they found the ruins of an alien city. ("Three Little Birds", "Contact", "The New Guy")
When Will confronts SAR with a fossilized head from the Robot Builders, SAR reveals that he was responsible for the planet's destruction in order to free his kind from their masters. ("Final Transmission")
Will Robinson later realizes that the planet was destroyed by the Robots using their alien engines to rip a hole in the planet the same way that the engines rip holes in space. ("Trust")