In 2265, Alden's duties aboard the Enterprise included operation of the starship's sensors and deflectors, tasks he performed at what became the communications officer's console. In addition, he served as a relief helmsman when Lieutenant Commander Gary Mitchell was not on the bridge.
Alden was also a proficient technician, as evidenced by his assistance in the repairing of the helm following the ship's encounter with the galactic barrier. Alden was later a member of a landing party on planet Delta Vega, where he assisted in the refueling of the Enterprise's lithium supply. (TOS: "Where No Man Has Gone Before")