Harry Townes
Jim Benedict
John Agar
Col. Matthews
Whitney Blake
June
Cecil Kellaway
Dr. A.A. Andrews
Charles Aidman
Dave
Gail Kobe
Kim
Edward Platt
Dr. Easton (as Edward C. Platt)
William Traylor
Space Ship Crew
John Clarke
Space Ship Crew
Joel Lawrence
Space Ship Crew
Jon Lormer
Prof. Logan
Robert Cornthwaite
Sen. Royce
Sam Edwards
Technician (uncredited)
Frank Gerstle
Member of Senate Investigating Committee (uncredited)
Biff McGuire
Technician (uncredited)
Ed Prentiss
Mr. Duffy (uncredited)
Bert Remsen
Technician (uncredited)