Justice Prime

Justice Prime was a small and cold planet, so cold that the nitrogen on the surface was turned into snow as it moved away from the sun. It was the only planet in the Justicia system not to have a circular orbit. This planet was the first to be used as a prison planet, specifically for alien criminals. The criminals were kept underground in the SCAT-house (Species-lead, Creative and Advanced Technologies). It was there that the Doctor was sent after being captured on Justice Alpha. (NSA: The Monsters Inside)