In 1989, the US and Russia have lunar bases with two-person teams. The Americans replace their male teams due to mental instability, assuming only men would avoid impropriety. The Russians, with a male-female team, remain well-adjusted. A new American team, a married couple, is sent to replace the all-male team, with most of the story focusing on their relationship and interactions with their Russian neighbors.
Way... Way Out
In a futuristic world, the US sends a married couple of astronauts to its lunar base to maintain a safe distance from Soviet cosmonauts stationed at the USSR moon base.