You just need to float down the trench and operate three cannons
Dead Space once again is filled with some light puzzles (or activities) to do, including the recalibration of the ADS cannons. Here’s how to navigate that sequence, and when it actually takes place.
You’ll reach the ADS cannons near the end of Chapter 4
So near the end of Chapter 4, directly after the sequence where you can find the Contact Beam and battle several brutes, you’ll come across the main story objective to recalibrate the ADS cannons. This is a required portion of the campaign, and it’ll take you outside of the ship, with the intent of calling strikes on meteors to calibrate cannons to shoot at them automatically.
To do that, you’ll need to coast over to all three monitor screens on the sides of turrets (pictured above), and interact with them to get the cannons online. Then, you’ll aim (L2/LT) and press X on PlayStation platforms (A on Xbox) to “call a strike.” This essentially tells the turret where to shoot. Aim at the meteors flying at the ship, then call the strike to connect with them. Once that cannon’s percentage level is 100%, move to the next cannon. Each cannon is controlled via a monitor further down the trench.
Once you’ve calibrated all three ADS cannons, float back to where you came and head back into the ship to continue the story.
Make sure to keep an eye on your oxygen levels
Since you’re out in the vacuum of space during this objective, you’ll want to keep an eye on your oxygen levels. Note that the sides of the trench have oxygen replenishment stations available, so if you’re running low, just boost over to one and interact with it.
During the cannon sequence you’ll be pelted by some ranged enemies, so focus on taking them out and getting some oxygen; then going back to the task at hand.
