Kokytos
Kokytos was an uninhabited class L moon in orbit of Theta Helios. It had a humanoid-breathable atmosphere with frequent bouts of dangerous spider lightning. The surface was barren and largely covered by snow and ice, including patches of parasitic ice. The moon was home to the Tuscadian pyrosome, a predatory colonial lifeform that fed mainly on bioluminescent crustaceans.

In 3190, the Federation shuttlecraft UFP-11, carrying a group of Starfleet Academy cadets on a team-building exercise led by Lieutenant Sylvia Tilly, crashed on Kokytus after being struck by a rogue gamma-ray burst. Despite drawing the attention of a pyrosome, the group was able to trek to a nearby ridge and contact the  for rescue. ()

Moons