was the commander of Space Station W3
He was concerned that the Silver Carrier would hit his station and ordered it destroyed by X-ray laser, unaware that the Second Doctor and Jamie McCrimmon were aboard.
He and Bill Duggan later caught Jamie sabotaging the laser.
Jarvis was unhappy with the mysteries on his station. He didn't believe the Doctor's explanation that Cybermen were able to board the station and thought his crew was suffering from space sickness.
When the Cybermen invaded the station, Jarvis was killed when he tried to fight a Cyberman. (TV: The Wheel in Space)