The name on Travis' helmet switches between 'Ryer' to 'Travis' several times throughout the movie.
After every time travel safari, Charles Hatton greets and welcomes back his guests, comparing them to Columbus, Marco Polo, Armstrong, and 'Brubaker landing on Mars.' In 1978, director Peter Hyams, directed Capricorn One [and A Sound of Thunder], a film about a staged travel to Mars. Three astronauts were involved - Lt. Willis, Cmdr. Walker, and Col. Brubaker.