Novastrike

Here's the full strategy, copied straight from Pooshonmyshoos's thread:

1. Start off right away by unloading the Disperser and Heavy Rockets into its outer component that’s facing you while it’s on the way to the first stop

2. Keep using the electro-mines and beam to wipe out the Daggers the Harbinger launches to get more megapacks (and more Disperser and Heavy Rocket ammo) – this way you can keep attacking the Harbinger with the heavier weaponry. Also, it can be useful to drop mines in the path of the Harbinger not just to kill the Daggers but to damage the outer components as it passes

3. When the Harbinger reaches the first stopping point don't kill off the shield conduits right away, instead use electro-mines to farm the Daggers some (so they drop megapacks) to get your Disperser and Heavy Rocket ammunition filled back up

4. After you’ve gotten ammunition again you can kill the shield conduits so that it starts moving toward the second stop – again, unload the Disperser and Heavy Rocket on the Harbinger’s outer component that's facing you. Try to make sure Daggers won't intercept projectiles (especially heavy rockets), the goal here is to try to take out the weapon components (at least three of them, potentially four) before it reaches the second stop

5. Once it reaches the second stop go ahead and repeat step 3 – don't wipe out all of the shield conduits until you're refilled you Disperser and Heavy Rocket ammunition, then finish off the shield conduits so the Harbinger begins its journey to stop #3

6. While the Harbinger is on the way to stop #3 keep attacking the outer components with the heavy weaponry. If you can wipe out all the weapon bays and one hangar (so five of the eight outer components destroyed) then you can basically do an outer circle that in the same direction that the Harbinger is rotating – using your afterburner you can get it so you can afterburn along with it, then turn and face it and attack it with the Disperser and Heavy Rocket (where it's exposed), then continue doing this more. You’ll need to keep picking up megapacks to replenish your heavier weaponry, of course.

7. Even if step 6 doesn’t finish it off before it reaches stop #3, you can then replenish your heavy ammunition weaponry again, then once again let the Harbinger loose by destroying the remaining shield conduits. Now it’s headed toward the final destination so you need to kill it before it reaches the last stop. Repeat circling it with the afterburn to attack its exposed spot – if this proves difficult then you can try killing another hangar off (so six of its eight outer components destroyed) that’s facing you giving a bigger exposed area to target.

Note that you can also use the beam and electro-mine when you're circling around it to further damage it.