Scientific Pursuits

 is a Fallout 3 quest. It is also a Xbox 360/PC achievement and a PlayStation 3 Trophy.

Objectives and walkthrough
This quest can be started by talking to Madison Li in the Rivet City Science Lab, without completing the Galaxy News Radio quest. It can also be started by picking up the notes in Jefferson Memorial regarding Project Purity.

Gain entrance to Rivet City
It is highly likely that you have already visited Rivet City, likely as part of The Wasteland Survival Guide or in the course of visiting the southern Metro Stations to reach areas like Museum of American History or the National Archives. In this case, reaching Dr. Li is trivial.

The easiest - as in, quickest and no or almost no combat - way to get to Rivet City is to go back via the Map Marker in your Pip-Boy 3000 to Super-Duper Mart.
 * From there, follow the river (Potomac) south on the west bank, passing Wilhelms Wharf, down to the Arlington Memorial Bridge at the Citadel.
 * You can either avoid a few Super Mutants by swimming over at the Jefferson Memorial, or you can cross the Arlington Memorial Bridge and head south after a brief battle.
 * When you have the Jefferson Memorial in sight, head east. Near the Anacostia Crossing metro entrance you will notice a metal construct next to the aircraft carrier ; climb it and use the intercom to get the bridge connected.

You can also cross the D.C. urban area, dodging in and out of metro stations, or follow the east bank of Potomac, and it will lead you to a lot or at least some more combat.

Depending on your earlier missions - The Power of Atom in particular - you may run into Talon Company or Regulators.

Talk to Doctor Li about Dad and Project Purity
Dr. Li knows your father, James. She offers details on Project Purity and tells you where your father James ran off to: the Jefferson Memorial. If you've been to this location and visited the underground tunnel, the game will allow you to tell her that he isn't there; she will instead insist that you go back as his notes were left there.

Look for Dad in Project Purity's Control Room
Enter the memorial through the metal door labeled Gift Shop, it's on the right front side with a metal frame around it and a set of lights next to it.. Be warned that there are a number of Super Mutants inside. Make your way to the Rotunda by following the signs.

Once in the Rotunda, walk up to the auxiliary filtration unit near the entry way and pick up the log tapes resting here. One of the tapes, #10, will indicate that your father has left for Vault 112 already. The location will be added to your map; there are several other points of interest in the area, which makes it relatively simple to fast travel to.

Gain access to Vault 112
Walk or fast travel to Smith Casey's Garage. Once inside progress past the front desk and into the back room, killing the radroaches and mole rats. You will find a switch located on the wall to your left that operates a large hole in the floor. Activate the switch and the door will open. Proceed down the stairway, down the next set of stairs and to the bottom. You cannot miss the Vault 112 doorway. Activate the door using the panel and you can walk right in. Next walk down into the tranquility lab and find the single only operational tranquility lounger where you will complete the quest.

Rumors
It is rumored that it is possible to skip this quest by managing to get into Braun's office without ever sitting in a Tranquility Lounger. This is not true; there is nothing in that office which will end the simulation and release James. The only way to end the quest is to enter Tranquility Lane via a Tranquility Lounger.

It is also possible to complete the quest without gaining the achievement. Through over exploring, and failing to use the intercom for the Rivet City bridge, it's possible to bypass the Rivet City section completely, as you can stumble across the journals in the Jefferson Memorial (Project Purity HQ) without ever having met Madison Li... since not all of the objectives have been completed in order, this disqualifies you from receiving the achievement.

Also, you can just head straight to Vault 112 as soon as you receive the quest and it will update the quest to that point, although the dialogue will be the same and therefore not joined well to the plot your character will have followed.

Achievement
It is possible to skip major portions of this quest, for example by speaking directly to Dr. Li in Rivet City before visiting Three Dog, or by visiting the Jefferson Memorial or even Vault 112 directly. In these cases, this achievement will still be rewarded at the same time that the Tranquility Lane achievement is received.

Bugs

 * Sometimes the quest fails to update when you enter Vault 112. If this happens, you will not receive Vault112 jumpsuit from robobrains, nor find any in the vault itself and will be unable to continue with the main quest. This can be fixed by adding item with console command "player.additem 000340EF"