Mister Lopez

 is a 65-year old suicidal resident of Rivet City in the year 2277.

Background
According to the Fallout 3 Official Game Guide, his wife and child were killed by Raiders, and he has fallen into a depression ever since. This is probably the cause for his suicidal behavior.

Interactions with the player character
Lopez considers committing suicide due to the fact that no one remembers him or even cares about him (also learned by talking to him on the Flight Deck that he couldn't save his family.), but he doesn't have the courage to do it himself. The player can either help him find a new purpose in life or push him over the edge (literally.) If you wish to do so, be on the deck of the ship at 3 pm.

You can find him at top of the ship, but you'll have to enter through the stairwell and from there go up the stairs and you'll find a door that has a sign on top that says "Bridge Tower". Once you enter inside go up the small stairs and as you walk out turn to your left or right (Depending on the position of your screen). You'll find a sign that'll say "Marketplace". Once you have located the sign you'll see some stairs. Go into the hall then go up stairs and repeat the process 3 times til you enter a room that only has one door. Once you are in that room enter it and you'll be at the highest point of Rivet City. If you see the ledge, that is where Mister Lopez will be. Make sure you don't fall with him, though; it might result in crippling both legs, or worse, death.

Appearances
 only appears in Fallout 3.