“Initial tests of the override system are promising. Against unsecured or lightly-encrypted targets, the Eyebots have a 98% success rate. More heavily protected systems are still problematic. Military-grade encryption presents a very real possibility of critical overload of key systems.”— Dr. Whitley, Experiment log 369248/A
To complete this quest, the Courier must proceed to the Control Panel from which the missiles may be launched. Should the courier desire to select "Attempt to cancel the launch.", ED-E must be rescued first. If not, the quest fails and leads to The Apocalypse.
In order to rescue ED-E, the courier must free him from his pod in the repair room near the elevator to the temple. ED-E is located in pod number 2 and can be released by using the terminal on the table in front of the pods.
Once ED-E has been rescued and the Courier has dealt with Ulysses, proceed to the launch control pad and select the option for ED-E to hack it. This will initiate a recording from Dr. Whitley. The following dialogue will explain that the eyebots can override heavily encrypted data, but will probably not survive the process.
Everything that ED-E is carrying will be returned to the Courier's inventory after the quest.
Prior to the Lonesome Road DLC being released, there was no legitimate way to acquire the positive reputation needed with the Brotherhood of Steel for Idolized status with the faction. Completing the Lonesome Road DLC by stopping the missile launch in this quest, alongside all other Brotherhood quests in the base game, is the only way to reach Idolized with the Brotherhood legitimately.
If the player character has a reputation that does not allow Veronica Santangelo to become a follower, the reputation increase with the Brotherhood of Steel will then allow them to have Veronica as a follower if one chooses to visit her after the conclusion of Lonesome Road.