The rumors you picked up at Outer Wilds’s Southern Observatory on Brittle Hollow will point you to the Orbital Probe Cannon orbiting Giant’s Deep.
This guide will walk you through all there is to discover and explore there.
Orbital Probe Cannon
The first trick to exploring the Orbital Probe Cannon is just finding it. Giant’s Deep is a large planet, and it’ll pull you in if you’re not careful. You’re looking for a station that’s orbiting the planet. It looks similar to the Gravity Cannon on Brittle Hollow. You will have to watch for the various chunks of space debris getting launched out of Giant’s Deep.
Once you spot it, you can land your ship on the glowing blue pad, or you can just match your velocity to the cannon (to make sure your ship doesn’t float away) and spacewalk over to it.
Open the hatch to get inside. In the main hall, there are three tunnels to explore: Control Module, Launch Module, and Probe Tracking Module. The tunnel is open to the Control Module, the Launch Module is blocked (and damaged), and the Probe Tracking Module is … missing.
Head into the Control Module first. Drop to the floor — both the ceiling and floor have gravity tiles, so we’ll call the one with the projection pool the floor.
Pick up the Launch Module projection stone, slot it into the projection pool, and then the blank wall pedestal. Read the Nomai notes.
Pick up the Giant’s Deep projection stone, and do the same.
Head to the small pad with three gravity crystals over by the door. This will flip you and send you to the ceiling.
There, use the ball in the tube to see three simulations of the fate of the Orbital Probe Cannon. Each time you activate a simulation, you’ll get some Nomai script that reports on the various modules. (You have to read them all to get the Control Module marked off on your rumors screen.)
Go back to the main hub.
To get to the Launch Module, you’ll have to go outside. You can use the tunnel that used to lead to the Probe Tracking Module or go back to your ship.
Enter the Launch Module through the cracked window.
Drop to the floor and grab the floating Control Module projection stone. Fit it into the projection pool and blank wall pedestal.
Do the same with the Probe Tracking Module projection stone.
What have we learned? // What’s next?
The Orbital Probe Cannon gave us more information about the Construction Yard on Giant’s Deep — and we know how to get down into Giant’s Deep from the Southern Observatory on Brittle Hollow.
We also know that the Probe Tracking Module that might have information about the Eye of the Universe is probably down in Giant’s Deep somewhere.
Which means it’s time to go down to Giant’s Deep.