Rosa Meitner

 is a Wastelander in 2277. She appears the first time you exit the Megaton gates after completing Take it Back!.

Daily schedule
Rosa is a kind-hearted soul, and gives Micky the water beggar a bottle of "blessed" water that she picked up walking through Springvale. This kills Micky, unfortunately.

Rosa, fearful for her own life, will immediately run away into the Wasteland.

Effects of player actions
Rosa and Micky's little incident is one of the ways that you can start the Holy Water quest. You can also grill her for info before she runs off; she can mark the location of the Holy Light Monastery on your Pip-Boy map.

Appearances
appears only in the Fallout 3 add-on Broken Steel.