When Cargraves and Thayer are watching the launch of the satellite at the beginning, they are looking out a window while facing away from the camera. Then, in one continuous take, they turn around to face the camera and walk out of the building to look at the wreckage that is now on the opposite side of the building they were in.
Early in the movie Sweeney is assigned the green suit and Cargraves the blue suit. In later scenes, they have switched suits.
While staging the picture of Sweeny we can see he has his left arm in the "air"; while the view of Sweeny immediately after the picture shows him with his right arm up.
The view of Sweeny with his right arm apparently up was a view through a waist level screen on a twin lens reflex camera, which reverses the image left-to-right. Image characteristics indicate this is an actual image from a TLR.
The view of Sweeny with his right arm apparently up was a view through a waist level screen on a twin lens reflex camera, which reverses the image left-to-right. Image characteristics indicate this is an actual image from a TLR.
The size of the "Luna" rocket varies. During the spacewalk, the ship (as compared to the crew walking on its hull) appears to be about 100 feet in length. After landing on the surface of the moon, when they're seen climbing down its side, it is nearly twice as big.
When they are leaving the moon, the background moonscape through the porthole drops out of sight as expected, but the earth at the top of the porthole doesn't move.
It was stated that titanium was being used to construct the ship. The magnet boots would not stick to the hull and walls because titanium is non-magnetic.
When Barnes attempts to rescue Cargraves, who has fallen away from the ship during the antenna repair, he uses a bottle of pressurized gas as a makeshift rocket to propel him to the point where he can retrieve him. However, the gas exhaust from the bottle is nowhere near Barnes' center of gravity, thus the expelled gas would simply flip him end over end.
When the crew of the ship are pushed into their seats by G forces, distorting their faces, their shirt collars show no effects. They should have been flattened as well.
The astronauts go outside the ship to unfreeze a stuck antenna. When one goes adrift and has to be rescued, he is rescued using an oxygen bottle as a makeshift rocket. After the rescue, the rescuer, Jim Barnes, drops the bottle, which falls quickly out of sight. That wouldn't happen in outer space where there is no gravity to pull the bottle down.
The astronauts go outside the ship to unfreeze a stuck antenna. When one goes adrift and has to be rescued, he is rescued using an oxygen bottle as a makeshift rocket. They go inside without any repair of the antenna being shown.
After Dr. Cargraves, in the blue suit, jumps on the moon, it is Sweeney, in the green suit, who is reprimanded for "clowning around." He is actually being scolded for throwing Cargraves up in the air, which he did to show off his ability to lift things he couldn't normally.
When first watching this film, it appears as though the crew looks through the round port that leads into the airlock to view the Earth outside the ship. This looks like a continuity error, but it is not - the confusion comes from the elaborate "special effect" of weightlessness generated with a rotating set and magnetic boots. The crew was squatting on the "wall" of the cabin and looking "out" through a round porthole on the outer wall of the ship, not down through the floor. There is indeed a round airlock door that leads down into a lower cabin where the spacesuits are kept, but it is not the same round port they looked through to see outside. The rotated perspective, the magnetic shoe use, and the two round windows causes this common misconception.
When the astronauts are supposedly in a weightless environment, there are several things -food, straps, first aid kit contents, etc.- that do not float despite not being fastened down in any way.
During the early scenes in zero-gravity, some of the wires are visible.
Although the characters mention that radio signals take 3 seconds to travel between the earth and the moon, earth replies arrive almost instantaneously during conversations with the men on the moon.
In the one scene a rocket is seen crashing, but remains partially intact. Rockets are built in a way that the fuel inside the fuel cells acts as a structural support. So when a rocket crashes there is not much left to see.
In long shots of the astronauts walking on their spaceship, it is obvious that stop animation models are used, which are proportionally large.
The banana a crew member eats whilst in space has an obvious prop skin as it is far too rigid.
When the astronauts emerge from the hatch during their spacewalk to repair the antenna, the shadow of one of the film crew can be seen on the open hatch door, helping push the cast members out onto the surface of the "ship".
During the moonwalk, studio lights are seen reflected in the glass visors of the astronauts' helmets.
Radiation readings from the surface below the rocket indicate it is radioactive. The exhaust from the nuclear-powered engine would likely be source of this. The readings should have been taken at a distance.
When Cargraves and Thayer are watching the launch of the satellite at the beginning, Cargraves tells the General, "They'll break your necks to get you back and raise your rank when they see what this'll do." Clearly, actor Warner Anderson (Cargraves) misspoke his line, which obviously should have been, "They'll break their necks...."