The three green card monuments compared: Sewer Branch, Satellite Dish, and Harbor. Requirements, puzzles, and what each rewards.
Sewer Branch, Satellite Dish, and Harbor are the three green card tier monuments. Their purpose is the same: give you a Blue Keycard to progress to mid-tier monuments. All are low-risk runs requiring minimal gear.
All three follow the same basic structure: Green Keycard and 1 Electric Fuse. Insert the fuse into a fuse box, flip a switch to power the door, swipe the Green Keycard on the card reader, and collect the Blue Keycard and loot inside. Green Keycards are found at Lighthouse, Supermarket, Gas Station, and Abandoned Cabins. Fuses are common from barrels.
Mild radiation (burlap set is enough). Single fuse box and switch, then swipe the card. Inside: 3 or more basic crates and a Blue Keycard. The easiest and fastest of the three. Full details in the Sewer Branch guide.
No radiation at all, the safest green card monument. Multiple switches in a specific order, then insert the fuse and swipe. Has a recycler on site. Full details in the Satellite Dish guide.
No radiation, no scientists. Small Harbor is a single building. Large Harbor uses two separate buildings. Both reward a Blue Keycard and a loot crate. Full details in the Harbor guide.