Miller seems to have seen “Apollo 18” as a mere proof of concept and hoped to leave the found footage conceit behind for its follow-ups. The sequels, Miller noted, would have been called (perhaps obviously) “Apollo 19” and “Apollo 20.” He also noted that he wanted to switch from horror to action, very much like another popular sci-fi film franchise from the 1970s and 1980s. In his own words:
“My idea there was that it would be a little bit bigger, a little more broader in scope. Kind of like ‘Alien’ versus ‘Aliens.’ James Cameron came in and obviously knocked it out the park with the big action version once Ridley [Scott] had done the small, contained version. That’s what I thought would be great: a big action movie on the Moon. Nobody’s really done that yet.”
Clearly, Miller hadn’t seen the films “Ad Astra,” “First Men in the Moon,” “Iron Sky,” “Moonfall,” “Transformers: Dark of the Moon,” or “A Trip to the Moon,” but one might take his meaning. Ridley Scott directed “Alien” in 1979, and it was a quiet horror movie about an alien creature running amok on a futuristic spacecraft populated only by blue-collar miners. In 1986, James Cameron made a sequel called “Aliens,” which ratcheted up the action and followed the adventures of well-armed space marines as they faced off against dozens of alien creatures and their queen.
It seems that Miller was a fan of Cameron’s follow-up more than he was of Scott’s “Alien” and hoped that his sequel to “Apollo 18” would be the “high octane” version of the original. Notably, “Apollo 19” also wasn’t going to be a found footage movie.