Scientific Pursuits

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

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 Jefferson Memorial in sight, head east. Near the Anacostia Crossing metro entrance you will notice a metal construct next to the broken hangar ship; 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 who your father is and offers details on Project Purity, then 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. 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
There is a large group of raiders outside before you get to Vault 112 so come prepared. The waypoint is revealed to be Smith Casey's Garage. Inside, the player will find several mole rats and a control switch, which allows access to a lower level leading directly to the Vault 112 door. Activate the control switch to open the Vault and step inside. A Robobrain will walk up to you, insisting that you put on a Vault 112 Jumpsuit, which it will give you before asking that you please enter a Tranquility Lounger.

Continuing downstairs, you will find a number of Tranquility Loungers in a circle. One is unlocked. Opening it and sitting in the pod will end Scientific Pursuits and begin Tranquility Lane.

Rumours
It is rumoured 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.

Getting the Achievement
To successfully get the achievement for this quest, you must speak with Three Dog in the Galaxy News Radio quest, and have him give you the quest, as opposed to going to Rivet City and getting the quest from Dr. Li. Receiving the quest from Dr. Li disqualifies you from getting the achievement, as the first objective in the quest is to find Rivet City, and completing objectives out of order or before getting the quest can disqualify you from certain quest-based achievements.