Salusa Secundus

Salusa Secundus is a fictional planet appearing in Frank Herbert's Dune universe. With harsh conditions rivaling those of the desert planet Arrakis, Salusa is used as the Imperial Prison Planet, and is one of two planets on which shigawire is grown (the other being III Delta Kaising).

Dune
In "Terminology of the Imperium," the glossary of the 1965 novel Dune, Herbert writes:

"SALUSA SECUNDUS: third planet of Gamma Waiping; designated Imperial Prison Planet after removal of the Royal Court to Kaitain. Salusa Secundus is homeworld of House Corrino, and the second stopping point in migrations of the Wandering Zensunni. Fremen tradition says they were slaves on S.S. for nine generations."

The Padishah Emperors of the known universe use Salusa Secundus as a prison planet, a penal colony where the "worst riff-raff in the galaxy are sent." Infamously known as a "hell world," the planet's climate is so severe that the "mortality rate among new prisoners is higher than sixty per cent." In the events of Dune it is also revealed that the Imperial House Corrino makes use of the planet as a secret recruiting and training ground for its fierce Sardaukar troops. After Paul Atreides ascends to the Imperial Throne, House Corrino is exiled to Salusa Secundus, with the exception of Padishah Emperor Shaddam IV’s eldest daughter, Princess Irulan, who is married to Paul.

Children of Dune
In Children of Dune (1976), Shaddam IV's third daughter Princess Wensicia plots from exile to assassinate Paul's twin children, Leto II and Ghanima, to retake control of the Empire for her son, Farad'n. Paul's mother Lady Jessica escapes a murder plot by her daughter Alia and travels to Salusa with Duncan Idaho; there she trains Farad'n in the Bene Gesserit ways in exchange for Wensicia's public banishment and the promise of his marriage to Ghanima.

Legends of Dune
According to the Legends of Dune prequel trilogy (2002-2004) by Brian Herbert and Kevin J. Anderson, Salusa Secundus is the capital of the League Worlds during the Butlerian Jihad, and the home planet of Serena Butler. In 2002's Dune: The Butlerian Jihad, Salusa is described as "a green world of temperate climate, home to hundreds of millions of free humans in the League of Nobles. Abundant water flowed through open aqueducts. Around the cultural and governmental center of Zimia, rolling hills were embroidered with vineyards and olive groves." In Dune: The Battle of Corrin (2004), the Imperial House Corrino is founded on Salusa Secundus by Viceroy Faykan Butler, the grandnephew of Serena Butler, who takes the name "Corrino" to honor mankind's victory over the thinking machines in the Battle of Corrin. This battle marks the end of the Butlerian Jihad, mankind's crusade against computers, thinking machines and conscious robots.

Prelude to Dune
The Brian Herbert/Kevin J. Anderson prequel trilogy Prelude to Dune (1999-2001) establishes that, after centuries as the capital of the Corrino Padishah Empire, Salusa is devastated by atomics before the events of 1999's Dune: House Atreides. Padishah Emperor Hassik Corrino III relocates the Imperial throne to Kaitain, and the renegade House which had perpetrated the attack is exterminated, their name erased from history. Salusa Secundus is intentionally left as a barren wasteland. The interquel novel Paul of Dune establishes that House Tantor had been responsible for the destruction of Salusa, and House Moritani are secretly descended from them.