A remote sector of Federation space that was home to the Regula I laboratory and the Mutara Nebula, where Khan was defeated and the Genesis Planet was born in 2285.
The Mutara sector is a quiet region of Federation space containing the planetoid Regula, the Regula I space laboratory and the nearby Mutara Nebula. Its isolation made it a suitable place for Carol Marcus's team to develop Project Genesis.
In Star Trek II: The Wrath of Khan, Khan Noonien Singh takes the USS Reliant to the sector to steal the Genesis Device. Kirk lures him into the nebula, where shields and sensors fail, and the detonation of the device turns the nebula into a new world. Spock dies saving the Enterprise.
In Star Trek III: The Search for Spock the sector is placed off limits while the USS Grissom studies the Genesis Planet. Kirk returns there against orders, loses the Enterprise and his son David, and recovers the regenerated Spock.