Sgt. James Conover / Major Harold Giles
Emmett Balfour / Professor Hebbel
Paul Cameron / Trent
Adam Ballard / Louis Mace
First Reporter / Chief of Staff
Coroner Leland / Bill Turner
Dean Radcliffe / Mr. Terrence
Detective Lt. Runyan / Dr. Paul Fredericks (uncredited)
Philip Exeter Dundee / Elder of Luminos
Budge / Bert Hamil
Randolph E. Branch / New Sentry
Lt. Rupert Lawrence Howard (uncredited) / James Custer
Ben Fields / Lincoln Russell
Capt. Terrence Ralph Brookman / Harvey Kry Jr.
Chino Rivera / General Juan Mercurio
Dr. Block / Aabel
Policeman / Navigator Dexter
The Mikie / Thetan (uncredited)
Andro / Richard Bellero
Yvette Leighton / Ann Barton
Ann Pearson / Prof. Stephanie Linden
Akada / Dr. Sui-Lin
Dave Crowell / Luis B. Spain
Henry Castle / Galaxy Being (as Wm. O. Douglas)
