Geryon was an uninhabited class M desert moon in orbit of Theta Helios.
In 3190, Lieutenant Sylvia Tilly volunteered to lead a group of Starfleet Academy cadets in conducting a full planetary analysis of Geryon as a team-building exercise. However, their shuttle UFP-11 was struck by a rogue gamma-ray burst en route and crashed on the moon of Kokytos instead. (DIS: "All Is Possible")
Geryon is a giant in Greek mythology renowned for his cattle.