Aiding the Outcasts

Aiding the Outcasts is a Fallout 3 quest that was added to the game in the Operation: Anchorage add-on.

The Brotherhood of Steel Outcasts are trying to acquire advanced military tools, and the only way to enter the vault containing these relics is by completing a military virtual reality simulation only the player can enter. In the simulation the player fights in one of the greatest battles of the Fallout universe: the liberation of Anchorage, Alaska from invading Red Chinese troops.

Investigate the Outcast Distress Signal
After installing the DLC, you receive a message about an Outcast Distress Signal and this quest is added to your Pip-Boy.

From the emergency signal you learn that Defender Morrill is asking anybody capable of receiving the signal for support at Bailey's Crossroads.

Bailey's Crossroads can be reached via Bailey's Crossroads Metro just south of the Red Racer Factory. This is a fairly standard tunnel system occupied by a few feral ghouls.

Help the Outcast soldiers
At Bailey's Crossroads a battle is taking place between super mutants and Brotherhood Outcasts, who will mistake you for a Brotherhood Outcast if you have their armor. The battle progresses through a building until you reach the Outcast Outpost guarded by mark IV turrets. Once there, Defender Morrill, who led the Outcasts to the Outpost, asks you to speak with Protector McGraw at the bottom of a freight elevator.

Killing The Outcasts
You can still go into the Anchorage Simulation if the Outcasts are killed. Simply take the neural interface suit from Specialist Olin.

Talk to the leader of the Outcasts
Arriving at the bottom of the elevator, you are greeted by Defender Sibley. Not too happy to see you (unless you are wearing Outcast power armor or make use the Black Widow option), he asks you to keep your mouth shut and follow him. He leads you to Protector McGraw who explains that there is some high-tech equipment locked away and only you with your Pip-Boy can complete the VR program and gain access. This VR program is a simulation of the Anchorage Reclamation. The simulation's safety measures, as a must, have been disabled - dying in the simulator means death in the "real" world as well. The Protector then asks you to follow Sibley to Specialist Olin.

Explore the VSS installation
Olin can be found in the room with the simulation pod. She hands you a neural interface suit which according to her is required to be able to participate in the simulation.

Enter the simulation pod
Once you put the suit on, open the simulation pod and activate it. This quest is concluded and you find yourself inside the simulation at the beginning of The Guns of Anchorage.

Bugs

 * Somewhere along the way into the Outcast Outpost you may lose Ol' Painless from your inventory so be careful and leave it somewhere safe before setting out on this mission.
 * The Outcasts will sometimes turn hostile if hit with a grenade from a super mutant, so save before exiting the Metro.
 * If you have the "You Gotta Shoot 'Em in the Head" quest still open, it will be marked complete once you equip the suit of power armor from the armory at the end of this DLC. This can be useful if you are experiencing the "non-completion bug" for this quest and want it removed from your active list/completed. You receive no extra XP for this, however, as you would for completing the quest as normal (this has been fixed in latest updates for Fallout 3 on PC, GOTY edition).
 * If you have completed the first part of the mission, and Defender Sibley is leading you to the Outcast commander, leaving will cause a very odd bug. Sibley will follow you, and will occasionally appear in the oddest places. He has been encountered in the Enclave Mobile Platform (Broken Steel), outside Rivet City, Raven Rock, The Citadel, in the Republic of Dave, and Tenpenny Tower.
 * It is possible that after downloading Operation Anchorage you will not receive the radio transmission at the start of the game and will not be able to get into Bailey's Metro.
 * The final objective, "Enter the simulation pod", may never be marked as complete, even after the whole simulation is completed, therefore rendering the quest technically unable to be completed and forever present in the Pip-Boy's active quests.