The Ellesant were a civilization that lived on the third planet in an unexplored star system (as of the 2260s), in a sector located beyond Starbase 25. In the last year of his five-year command of the Enterprise, Captain James T. Kirk discovered the Ellesant's home system.
As of the late 2260s, their homeworld had a global population of three and a half billion. They were pre-warp but had interplanetary travel, settling on one of their homeworld's three moons as well as the fourth planet in their system.
When the Enterprise crew scanned the system, they noticed a massive asteroid on a collision course with the fourth world and its 100,000 inhabitants. The impact would lay waste to the world, killing off the population. The Ellesant knew the asteroid was coming and tried to destroy it as well as evacuate the world, but both efforts failed to prevent the upcoming deaths of the colonists.
Ignoring the Prime Directive, Kirk ordered his crew to fire the ship's phasers and photon torpedos to destroy the asteroid. He saw no moral reason to allow so many to die when they could be saved. Unable to hide from detection by the Ellesant, Kirk had to decide whether or not to establish contact, in which he chose contact. (TOS novel: Allegiance in Exile)
- The outcome of this contact is unknown.