Project Purity

 is a mysterious scientific project that started before the beginning of Fallout 3. In Rivet City, Dr. Li will tell the PC that his father, James, left Vault 101 to travel to Rivet City to start the project up again. Dr. Li refused and James moved on.

Related quests
The project is tied to Following in His Footsteps, and possibly tied to The Waters of Life as well.