Pezun is an asteroid base located in Lagrange Point 4 near Sides 2 and 6. It was one of three asteroids that the Principality of Zeon used as staging points during the One Year War. During the war Zeon moved the asteroid Pezun to L4, between Sides 2 and 5, in order to guard it's other flank in a mirror image of Solomon. The asteroid was used as a base for developing Mobile Suits, such as the MS-10 Pezun Dowadge. Like Solomon, it became a Federation base after the war, who inherited it's mobile suit R&D center. Pezun became the home base of the Titans Mobile Suit Instructor Corps. When the Earth Federation disbanded the Titans in 0088, the Instructor Corps seized Pezun in a military coup, declaring themselves the New Desides. In March 0088, a Federation task force was sent to Pezun to quell the rebellion. After several days of fierce fighting, the New Desides decided to escape their base and detonate it using nuclear warheads, in order to cause damage to the Federation fleet.
- Originally, MS-X established a number of Zeon mobile suits developed as part of the "Pezun Project". However, what "Pezun" meant was never explained until Gundam Sentinel established that it was the asteroid base where the project took place.