Trivia: The "old gangster movie" that's on the TV in Harry's apartment is the fictional movie "Angels with Filthy Souls," which was seen in the movie "Home Alone." The director wanted a detective movie for the scene, and said: "We needed something and I hadn’t figured out what I was going to put on that TV yet...Just as a laugh, we got the movie that they shot for Home Alone off of YouTube...We could never beat it!"
Trivia: During the feast in which Christian finds a pubic hair inside of his food, look closely at the drinks on the table. While the camera never calls direct attention to this, if you look closely, Christian's drink is very slightly darker than everyone else's. Earlier in the film, the camera briefly passes over a mural that depicts a woman collecting menstrual blood in a cup. (Along with the image of a woman cutting off pubic hairs, like the one Christian found in his food.) It seems Christian's drink has been laced with something he didn't expect.
Trivia: K Callan, who plays Christopher Plummer's mother in this film, is actually six years younger than Plummer in real life.
Trivia: When Roy McBride is reviewing a top-secret message regarding his father and the LIMA mission, the message filename is "6EQUJ5," which is a very obscure easter egg in the movie. The filename 6EQUJ5 refers to the real-life "WOW Signal," a deep space radio signal received by the Big Ear radio telescope at Ohio State University in 1977. The alpha-numeric designation "6EQUJ5" was a printed readout of the signal's duration and intensity. This signal lasted 72 seconds and was 20 times stronger than background radio noise, causing a surprised astronomer to circle the printed 6EQUJ5 readout in red ink and make the handwritten notation "WOW!" in the margin. While the signal was an anomalous one-time event that was never repeated, and there is still no proof that 6EQUJ5 was alien in origin, it has stimulated debate about extraterrestrial radio signals for decades. Ironically, the movie "Ad Astra" concludes that there are no alien radio signals and that we really are alone in the universe.
Trivia: The movie was filmed in a full-frame aspect ratio and in black and white in order to help put the audience into the film. The aspect ratio was chosen in to make the film feel more confined and closed in. And it, along with the black and white filmstock, also helps the film feel aged and older.
Trivia: Spoilers. In the end, Dr. Butler and his wife Stephanie are revealed to be the killers. They were actually the killers in the original script for the first film, but the ending was changed several times until the final version seen in theaters with Lori being the killer. The original idea was recycled into this film, since the dimension-hopping angle of the story allowed the presence of a new version of the killer.
Trivia: The cuckoo bird was used at the beginning of the movie to point out what a parasitic bird does - secretly lays eggs in the nest of another bird species and leaves them for the different species to raise as their own. Another "brood parasite" that many people might be more familiar with is the Brown-headed cowbird. If all goes as intended, the different species, such as a Cardinal, will take care of the eggs until they hatch and continue feeding fledgings. Sometimes, "alien" eggs are evicted.
Trivia: The Mermaid spit "ink" at Dr. Beyer in his car. This suggests a Mermaid is similar to an octopus, squid, or cuttlefish (which have "ink sacs" - though anal, not oral!) and is a type of mollusk, not fish. However, mollusks are invertebrates, and the Mermaid in the movie apparently had a spine/backbone. (01:13:28)