Nemesis

The Nemesis was the personal flagship of the Fallen, aka the Failure, which he used to aid in his fight against the Autobot Rebellion that occured on Earth millions of years ago. When the Fallen's brothers united to stop him from destroying planet Earth he fought against them with all his might, but was eventually overpowered and severely injured. Whilst his brothers could not kill him, they rendered him mortally wounded and stole his Matrix of Leadership. Angered and wounded, the Fallen retreated to his ship and hooked himself up to the main power supply to keep him alive.

What the Failure didn't realise, however, was that the massive power drain on something as simple as a starship needed to support to life of a Cybertronian completely drained the shields, weapons and engines of the ship and left it drifting. That wouldn't have been that much of a problem, however, if it weren't for the fact that the ship was immidietly impacted by a massive asteroid. With the main hull shattered and the engines destroyed, the ship crashed on one of Jupiter's moons. The Fallen then stayed there for millenia until Megatron came to get him.

The Fallen abandoned the ship when Megatron told him that he had killed Optimus Prime (who was later resurrected) and the ruin stayed on the moon it had crashed on from then until the end of time. Great.