Steadfast and dedicated Helmsman of the USS Enterprise under the Command of Captain Christopher Pike. Lt Kelso showed great character and a true potential for further success. When James Kirk accepted command of the Enterprise, he kept Lt Kelso on board to ensure a smooth transition between commands. Unfortunately, Captain Kirk's good friend and ships Navigator Lt Cdr Gary Mitchell became infected with an unknown agent resulting in Lt Cdr Mitchell developing high levels of telekinesis and madness. Lt Cdr Mitchell in his ailing state was directly responsible for the death of Lt Kelso.