Location from The Expanse by James S.A. Corey
Jupiter's volcanic moon. Site of Jules-Pierre Mao's secret protomolecule laboratory where Dr. Strickland created the hybrid soldiers using kidnapped children, including Prax's daughter Mei.
Mao chose Io because nobody goes there voluntarily. The radiation environment is lethal, the surface is unstable, and Jupiter's magnetosphere makes electronics unreliable. Perfect conditions for a laboratory that needed to remain hidden while conducting experiments that would horrify anyone with a conscience. Dr. Strickland ran the hybrid program from Io, using children with compromised immune systems as hosts for protomolecule integration. The children were kidnapped from Ganymede's pediatric facilities — kids with immune disorders whose disappearance could be explained by the station's deteriorating medical infrastructure. Mei Meng was one of them. The Rocinante crew and a UN Marine detachment assaulted the facility, racing to stop Mao from launching the hybrid soldiers as weapons. The battle of Io was a convergence point — Holden's crew, Bobbie's Marines, Avasarala's political maneuvering, and Prax's desperate search for his daughter all collided in a volcanic hellscape above which protomolecule hybrids launched toward Mars on stolen drives.
Io is hell — the most volcanically active body in the solar system, its surface a constantly reshaping landscape of sulfur plains, lava flows, and erupting vents. The research facility is buried deep underground, shielded from radiation and volcanic activity. Inside, sterile laboratory corridors contrast with the chaos above — clean rooms, containment chambers, and medical bays where children were kept in induced comas while protomolecule samples were introduced to their bodies. The facility has the clinical horror of atrocity committed with proper documentation.
Also known as: Io, Io Station, Io Research Facility