|The following is based on information from Van Buren design documents and is not canon.|
Once in the vault, the Prisoner can talk to the Zax computer there and convince him to reveal where he receives his orders from. He will then tell the Prisoner of the satellite dish atop the canyon wall.
Get to the Twin Mothers Dish, clean the solar panels on the roof and activate the computer terminal.
Above the canyon that houses the Twin Mothers tribe, there's a plateau which holds the Twin Mothers Dish entrance. The entrance is hidden behind some boulders, but on closer look one can find the entrance with relatively no trouble.
Upon entering the Twin Mothers Dish, the Prisoner will be in the main room, which holds a computer terminal that is used for the communication and tracking equipment of the satellite dish, but querying the computer for the coordinates is useless, since it will ask for proper access codes. They will also notice that the facility is lacking power and cannot run in operational mode. Going further the facility, into a side room, reveals that the fusion reactor which powered the facility, has failed and it's now running on backup batteries which are charged by solar panels on the roof. However the power that solar panels offers is too low to power the facility.
Going to the roof and taking a closer look at the panels reveals that they are covered in sand and dirt. Cleaning them will allow the batteries to charge to full capacity, given one entire day for them to charge.
Once the station is operational the computer terminal will begin to flash a warning message: "Signal source lost." If the Prisoner investigates this they will find that the dish is locked onto an unknown ground based target to the southeast and cannot be redirected. Any attempt to do so results in the computer demanding security access codes.
- If your skills in Science and Outdoorsman is high enough, you can examine the mechanism that moves the dish in the final room of the facility, and glean the coordinates. This will mark the World Map with a location labeled as "Unknown."