Comic Title: Challengers of the Unknown #73
Publisher: DC (National Periodical Publications, Inc.)
Address: 909 Third Avenue, New York, NY
Cover Date: Apr/May 1970
On Sale Date: January 29, 1970 Newsstand Date January 29, 1970
Source: Comic Reader, #77

Copyright Date January 29, 1970
Source: Library of Congress, Periodicals 1970

Newsstand Date February 3, 1970
Source: House Ad, Flash #196, Page 11

Newsstand Date February 26, 1970
Source: House Ad, Unexpected #118, Page 20

Frequency: Bi-monthly
Cover Price: $0.15
Page Count: 32
Circulation: 140584
Editor: Murray Boltinoff

Title: "The Curse of the Killer Time Forgot"
Pages: 23

Feature(s):
Challengers of the Unknown (of Earth-1)

Writer: Dennis J. O'Neil
Artist: George Tuska

Feature Character(s)

• Challengers of the Unknown (last appearance in Challengers of the Unknown #72; next appearance in Challengers of the Unknown #74)
• Ace Morgan (last appearance in Challengers of the Unknown #72; next appearance in Challengers of the Unknown #74)
• Red Ryan (last appearance in Challengers of the Unknown #72; next appearance in Challengers of the Unknown #74)
• Rocky Davis (last appearance in Challengers of the Unknown #72; next appearance in Challengers of the Unknown #74)
• Prof. Haley (last appearance in Challengers of the Unknown #72; next appearance in Challengers of the Unknown #74)
• Corinna Stark (last appearance in Challengers of the Unknown #72; next appearance in Challengers of the Unknown #74)

Villain(s)

• Major Cheever (an astronaut; dies in this story; no further appearances)
• Machu (an alien entity; no further appearances)

Other Character(s)

• An unnamed astronaut (dies in this story; no further appearances)
• An army general and various soldiers (no further appearances)

Synopsis:
A space capsule returns to Earth carrying a lone astronaut. When the capsule is opened, the man inside is found strangled to death. The Challengers are called in to investigate. Corinna Stark senses a ghostly presence, then someone tries to kill her. She survives and convinces the team to hold a seance. After making psychic contact, the ceremony is interrupted by a grenade. Rocky smothers it, and Corinna tells them to head for the moon.

Ace, Red, and Corinna join Major Cheever on a space flight. During the flight, Ace reveals that Major Cheever is behind the assassination attempts. The astronaut made contact with an alien named Machu who killed the first astronaut. Corinna convinces Machu that it was duped by Cheever. The alien turns against him and kills him before disappearing into space.