I am making a video game on-board an old, creaky, leaky space station, which is forgotten or mostly not cared about, drifting around some moon/planet, with a single lonely, weary astronaut on board. I want it isolated and introverted, thoughtful and wistful. A bit like the movies Moon, Silent Running, or 2001 (although not forgotten about, its protagonist is isolated and lonely). 

The technology involved should be highly realistic, with roughly todays technology level, and I prefer even more primitive, something like Mir would be excellent. My core problem is that real space stations are expensive, and require regular resupplies, and so are not very likely to be forgotten about..

My question to Worldbuilding community is HOW and WHY the station and astronaut came to be in this situation...  what events transpired to put him there (and then passed him by, leaving him mostly obsolete?). How can I justify the expenses and mission importance of placing a manned station somewhere, only to let it fall into obscurity? 

A good answer would also provide a vague, distant goal to keep the astronaut going about the daily grind of survival. Last man at his post when everyone else has moved on, etc. Astronaut should not be obsessed with his mission, but some point for his existence, however small, needs to be there.

An occasional message from mission control, and regular automated supply drops are permitted. Bonus points if the station is located somewhere with a beautiful view (like Saturns rings).