Space Brain - S1-E21
Continuity mistake: The number on Kelly's suit was 4. As Paul went to go out after Kelly, you see the number 4 on the control panel, then when he nears Kelly, it's changed to 3, suggesting the shot of the exiting person was re-used.
Answer: Not necessarily - The gravitational fields of Earth and the Sun could have deflected the moon away from the solar system.
Seniram