From Halopedia, the Halo wiki
SPARTAN-B170 was one of 418 candidates recruited in 2539 for training with Beta Company of the SPARTAN-III program. Trained by Lieutenant Commander Kurt Ambrose and Senior Chief Petty Officer Franklin Mendez at Camp Currahee on Onyx for six years, SPARTAN-B170 ultimately became one of the 300 candidates in Beta Company to undergo biochemical augmentation and enter active duty with the UNSC Navy's Naval Special Weapons.
In May 2545, Lieutenant Commander Ambrose attempted to have SPARTAN-B170 and Lucy-B091 deployed on a deep reconnaissance mission to avoid the anticipated bloodbath of Operation: TORPEDO. Though the fate of SPARTAN-B170 is unknown, Lucy ultimately remained assigned to Operation: TORPEDO later that year.