Other mistake: There is something drastically wrong with the design of the spherical 'Aries' moon shuttle. Some seats and many fixtures are 'upside down' relative to the up-down orientation of the shuttle itself, and we see loose food trays and equipment about the place as if this is routine. But - the shuttle is designed to land on the moon. What happens then? The moon has gravity, remember? There are going to be quite a few very disgruntled people dangling upside down like spiders, and there will be loose gear (and perhaps a stewardess or two) bouncing about all over the place. It is not a matter of stowing loose gear or lying flat on landing - some parts of the shuttle are upside down relative to others, which is why the stewardess has to do that famous 180 degree upside down walk. Whichever way you look at it the shuttle is going to encounter serious problems when it reaches a gravity well, which will occur whenever the engines are fired up, never mind landing on the moon.
Revealing mistake: When we see the space station from the cockpit of the approaching shuttle, the station does not appear to rotate because the shuttle is rotating at the same speed. OK...except that the station IS still rotating with respect to the sun, which means that the light source and shadows on the station should be moving.
Continuity mistake: The view of the front of the moon buggy shows the sunlight coming from the right side of the screen(Pilot's left shoulder) But when we see his view out the window, the sunlight casts shadows as if the sun was behind them.
Continuity mistake: Several times during Heywood's speech to the team at the moon base, his arms shift from his sides with hands in pockets to in front of him with hands on the podium.
Revealing mistake: When the astronauts are on the way to the monolith on the Moon, there are two windows seen within the interior of the small space shuttle. During their small lunch, in the left window, the horizon is seen as the surface of the Moon is flowing back against the direction of the flight. However, although sometimes this horizon fills up to half of the window, no horizon can be seen in the right window despite being located directly beside the left window. Nevertheless, the inclination of the Lunar surface should allow for it to be seen.
Continuity mistake: The Discovery's crew quarters has five beds, three for the hibernating crew, two for the Bowman and Poole. The exact beds occupied by hibernating crew changes from one scene to the next. This error is caused by Frank's last two running shots (the ones where the camera stayed just ahead or just behind him as he ran) having been accidentally reversed in editting. Frank's hair is parted on the wrong side and the sleep tube layout and the body positions within are precise mirror images of the layout seen in all prior and following shots.
Continuity mistake: When Floyd and his team are heading to the Lunar excavation site, they start to eat those synthetic sandwiches. One of the shots shows a closeup of Floyd. As he is right about to take a bite, the camera cuts back to a shot of the three men. However, Floyd's sandwich is instantaneously about a foot from his mouth and he is fully chewing. (00:47:50)
Continuity mistake: When Frank receives his parents' birthday message he is relaxing on the sun-bed. As the message drags on there is some intercutting with various other views about the room. One shot happens to be of the sun-bed from an alternative angle, and Frank is nowhere to be seen. In the next shot Frank is once again lying on the bed.
Revealing mistake: During the "Dawn of Man" sequence, the ape-man scenes were shot on an indoor stage with projected background images on a huge screen behind the stage. The screen itself was a highly reflective cloth. In most shots, it is quite convincing, but in several (especially when facing the aggressive, victorious group during the first fight, then again when facing the tool-using group in the last fight), the rear screen appears to be a patchwork of smaller pieces of cloth as very obvious puzzle-like shapes of varying reflectivity appear in the sky. Once you notice them, it's incredibly distracting. It was originally parallel strips, but they were VERY visible as vertical lines so they were torn into a patchwork to make lines less obvious. (00:08:35 - 00:18:00)
Continuity mistake: When the astronauts are approaching the monolith on the moon, the earth is clearly seen in a gibbous phase near the horizon. In the next scene, the sun passes behind the earth, which is now in a "new" phase overhead. The earth does not change its position in the lunar sky, and certainly cannot change phase that fast.
Factual error: On board spaceship Discovery, the crew's living area is the spinning centrifuge, which spins about its axis to generate a gravity-like acceleration at its perimeter, the floor. When exiting the centrifuge a crewman climbs a ladder from the floor up to the hub, where there's a door leading to other parts. When Poole & Bowman climb this ladder, it's evident that they're under full body weight the whole way up. But in reality they'd get steadily lighter toward the hub. In fact, they'd be practically weightless within a few feet of it.
Continuity mistake: For most of the sequence during which the Orion space shuttle closes in to dock with Space Station One, we see the space station rotating counterclockwise, as viewed from the side the Orion is approaching. But the first two times we see the station (immediately before and immediately after the scene in which Floyd's pen floats free aboard the Orion), it is rotating clockwise. It is also apparently rotating clockwise in the shot from inside the station, looking out at the approaching Orion. The stars in this shot are turning clockwise, implying that the station is moving anti-clockwise, hence must be rotating clockwise when observed from the Orion.
Revealing mistake: When Dave Bowman is attempting to break into the Discovery after being locked out by Hal you can see, reflected in the Pod window as the Pod is spinning around, the edges and top corner of the small set of the Discovery hatch area. (Second timecode is accurate for DVD release) (01:43:00 - 01:46:50)
Continuity mistake: On board the Aries Moon Shuttle is the famous scene when the Pan Am flight attendant serves a meal to Dr. Floyd and then retrieves additional meals, enters the doorway and walks 180 degrees up the wall and over to be upside down to deliver the meals to the shuttle pilots. However, from the outside view of the spacecraft, the pilots are sitting perpendicular to where the passengers sit and she should only have walked up the wall 90 degrees.
Revealing mistake: In the sequence of the shuttle approaching the moon the pilot talks to Dr. Floyd. Floyds food-tray moves away from his knees because of the zero gravity in the shuttle. But it doesn't drift straight away, it swings like a pendulum showing that the tray is hanging on a string.