PLAYED BY: Gary Lockwood
SPECIES: Human Male

Navigator of the U.S.S. Enterprise and close friend of Captain James T. Kirk. Both had attended Starfleet Academy together and Kirk requested Mitchell aboard his first command. Mitchell had taken a poisonoius dart on the planet Dimerus that was intended for Kirk and nearly died in the process. When the Enterprise crossed the galactic barrier in 2265, Mitchell's high ESP (extra-sensory-perception) rating reacted with the negative energy present in the barrier, bestowing him with extraordinary powers. Proving to be a danger not only to the Enterprise, but all of mankind, Captain Kirk had no choice but to maroon Mitchell on planet Delta Vega. When Mitchell escaped, Kirk was forced to crush him with a falling boulder. Although Mitchell had turned against his captain and friend, Kirk recorded in his log that he died in the line of duty.

PLAYED BY: Paul Fix
SPECIES: Human Male

Chief Medical Officer of the Enterprise in 2265, having replaced Dr. Phillip Boyce. Piper was attacked by Gary Mitchell when he and Dr. Dehner escaped from the detention facility, although, he lived. Piper was later replaced by Dr. Leonard McCoy.

PLAYED BY: Paul Carr
SPECIES: Human Male

Helmsman of the Enterprise in 2265, Kelso directed the repair party on Delta Vega and wired a self-destruct switch to be pressed in the event that Gary Mitchell escaped confinement. He was killed by Mitchell who telekinetically used a power cord to strange him to death.

PLAYED BY: Andrea Dromm
SPECIES: Human Female

Captain's yeoman aboard the Enterprise in 2265, having replaced Yeoman Colt who served Captain Christopher Pike. Although she was the captain's yeoman, Captain Kirk mistakenly referred to her as "Jones", which she corrected him on. She would later be replaced by Yeoman Janice Rand.