NASA’s reaction to Apollo 18 was basically to distance itself from the movie. It said the film was fiction, not a documentary, and criticized the marketing for making the fake mission seem real.

What NASA said

NASA’s spokesperson said the agency was only minimally involved, never saw a rough cut, and did not want viewers to mistake the movie’s “lost mission” premise for real history.

Why that mattered

The movie used a found-footage style, which made the “secret Apollo 18 mission” concept feel believable enough that NASA worried about public confusion. NASA reportedly viewed that as a publicity tactic rather than an accurate portrayal of space history.

In plain terms

So, NASA didn’t endorse Apollo 18 as real; it treated it as a fictional horror movie and made that clear publicly.

TL;DR: NASA’s response was negative and cautious: “This is fiction, not a documentary.”