Dr. Bixler says that Jupiter is volcanic. It is actually a gas giant with no solid surface for a volcano. Even at the time this was filmed, this was known.
When Stansfield is discussing his mission with Dr. Bixler, they point to a picture on the wall and make gestures toward it pointing out the solar system. It is obviously not the Milky Way galaxy, and, even so, it would have been impossible to have a photo of it from that angle and that far away. Even then, the solar system would not be visible from that distance.
Dr. Bixler informs Cmdr. Stansfield that the spaceship he'll be traveling in has "interstellar drive" and will travel 70 times the speed of light. As with many science fiction plots including such travel, this is impossible with light speed the fundamental constant of the universe.
Dr Bixler says planetary system is 141 light years away from Earth and the ship travels at 70 times the speed of light. The return journey is said to take 40 years. Travelling at 70 times the speed of light, the return journey should only take just over 4 years.
If Stansfield was in suspended animation, he wouldn't have been able to take himself out of it.
Even if Commander Stansfield had the means to survive so long, forty years in isolation and solitary confinement would have driven him insane.
None of the military personnel in the story wears any kind of insignia or devices on their uniforms.