When the space shuttle lifts off, it promptly turns into a Saturn V.
Simon's space suit changes drastically from when he is riding in the van and outside the spacecraft to when he enters it. The NASA patch moves from his left to his right on the suit, and the number of connections on the front changes from three to six and their placement moves - just to name two differences.
While playing a version of Villa-Lobos Bachianas Brasileiras #5, the caption states that it is sung in Italian, and that it is an opera. It is sung in Portuguese and it is not from an opera, but is a cantilena.
This film was made in 1980, a year before the first space shuttle launched. The filmmakers had no idea what the actual shuttle launch sequence would be, and it shows: Technicians on the pad only minutes before launch, no technicians near the crew hatch as the astronaut entered the shuttle, the shuttle interior layout all wrong, no 6-second main engine firing before launch, etc, let alone why NASA would launch this shuttle in the first place.
Simon spends 197 consecutive hours in his isolation chamber, which equates to over 8.2 days. However, he emerges exhibiting far less beard growth.
Maj. Gen. Korey is wearing two ribbons representing the same Republic of Vietnam Campaign Medal (top and bottom row on the right) and the Infantry crossed rifles lapel devices are missing from his uniform in some scenes. In other scenes the Army Commendation Medal ribbon has been correctly placed in the top row right and the Infantry lapel devices are present.