Sargasso

Sargasso was a human colony world. It was lush, with much vegetation and large deposits of water. Sargasso was the birthplace of SPARTAN Daisy-023.

In 2517, a six-year-old resident of the planet, Daisy, was captured by the Office of Naval Intelligence to serve in Dr. Catherine Halsey's SPARTAN-II program. Daisy was replaced with a flash clone to cover up her disappearance. She eventually escaped custody and returned to Sargasso to resume her civilian life, only to learn of the flash clone who had replaced her. Having lost all hope of resuming her previous life, Daisy returned to the UNSC to become a supersoldier.

Trivia
Sargasso was likely named for the Sargasso Sea, a region in the center of the North Atlantic Ocean.