What If NASA's Apollo Program Had Not Been Canceled?

"There's a reason we've never gone back to the moon," teases the poster for the new horror sci-fi flick "Apollo 18." The movie claims to reveal decades-old footage of astronauts on a secret mission two years after Apollo 17 — the last real expedition to the moon — flew in 1972. (Without giving away anything that isn't in the trailer, lunar aliens apparently share some blame for our 40-year absence from the moon.)

In actuality, NASA did prepare for Apollos 18, 19 and 20. But these missions were scrapped amid budgetary concerns and a decline in public interest.

"The whole world was glued to Apollo 11," said David R. Williams, planetary curation scientist at the NASA Goddard Space Flight Center in Greenbelt, Maryland. "But by the time they got to 16 and 17, the general public just really wasn't that interested anymore." [Lunar Legacy: 45 Apollo Moon Mission Photos]

Even before Apollo 11 — the first lunar landing in July 1969 — the government had already axed the program's loftier ambitions. Planners had envisioned Apollo leading to a lunar base, for instance, and a manned mission to Mars was entering the conversation....