From The Perry Mason TV Show Book (Revised)
Mitchell Heller (Robert Bray, who later played Corey Stewart, the forest ranger who adopted Lassie), an overworked astronaut, is marked as a murder suspect after his worst enemy, Major General Addison Brand (James Coburn) is murdered. The police figure Heller had motive since Brand stole his job and his girlfriend, and was suspected of stealing his valuable invention.

Perry believes Heller is innocent, and now he must figure out how a dead man can talk.

This is the episode where Paul—resisting all the way—goes for a spin in a simulated space capsule.