Takron-Galtos is the principal prison and criminal rehabilitation facility for the United Planets in the 30th century. It originally used to be Science Police's main base and their training academy, but was turned into detention facility by Lt. Zendak. The planetary prison is largely automated and houses high security inmates from all across the galaxy. The administrative staff at Takron-Galtos consisted of a warden and armed guards from the Science Police.
Takron-Galtos was created by Jim Shooter, Mort Weisinger and Curt Swan.
The 21st Century era
The Guardians of the Universe deposited many galactic criminals at Takron-Galtos, many of whom were apprehended by their militant charges the Green Lantern Corps. Galactic bounty hunter Lobo is also responsible for sending escaped felons to the prison planet (those he doesn't kill, at least). After the Sinestro Corps War, Superboy Prime burns an S in the surface that can be seen from orbit. At the conclusion of that story, Takron Galtos is yet again rebuilt.
The 30th Century era
It has become a prime location in stories involving the Legion of Super-Heroes and every member of the Legion's Rogues gallery has spent some time in its confines. Legionnaire Brainiac 5 has used his force field technology to protect the planet, however, it is often the target of criminals.
Major Story Arcs
During the Great Darkness Saga, Takron-Galtos was ravaged, its staff tortured and its inmates freed. During Crisis on Infinite Earths, Takron Galtos was disintegrated by an anti-matter wave. In Final Crisis: Legion of Three Worlds, Superboy Prime and the Legion of Super-Villains break into the complex and free its prisoners to bulk its army against the Legion of Super-Heroes.
In the alternate universe from the futuristic Justice League 3000, Takron-Galtos is a dumpster planet, once known as Earth. Under unknown circunstances, the original home from mankind became one thousand years later in one of the worst places of the universe. Takron-Galtos still hides a lot of secrets, including how were Blue Bettle and Booster Gold freezed for a whole millenum to be awaken soon.
Superman and The Legion of Super-Heroes
Takron-Galtos was once a harsh and uninhabited world until the Science Police selected it for their training facility. The facility grew over time to become a small prison and armory. Eventually, it grew into a maximum security prison for the worst criminal offenders. Prisoners were kept powerless by light-based pacification technology. Some of the more notable prisoners are the Fatal Five, the Legion of Super-Villains, and Alexis Luthor. The Fatal Five, in particular, are infamous for repeatedly escaping the planet. When Imperiex arrived, Takron-Galtos was liberated. The Fatal Five and the Legion of Super Villains used Takron to imprison members of the Legion of Super-Heroes until a surviving few turned the tide with Supermen.