Corrected entry: When the ark is breaking free from Zyra's passing, men slide I beams into the carriage to stop it. To the right of them is another crew of 6-8 people that are helping, as the shot changes angles these people vanish and reappear several times.
Corrected entry: After the rocket boosts itself to escape velocity the motors cut off and it coasts toward planet Zyra on inertia alone. During the coast everything within the ship should be in free-fall, weightless. Yet during the scene between Earth and Zyra everyone and everything is under a full g.
Correction: Just like they are in Star Trek, The Black Hole and thousands of other sci-fi films - artificial gravity, yet another film convention that is not a mistake.
Correction: The 6-8 people mentioned are different people, as they are wearing different uniforms, jump suits, hats, etc... They do not vanish and reappear as mentioned.