Destroy the Planetbuster is a mission in Ratchet & Clank. Ratchet and Clank found an infobot with a recording of Alonzo Drek presenting the PlanetBuster Maximus, a massive missile designed to destroy an entire planet into "sub-atomic particles". Angered by finally noticing Drek's true intentions, Ratchet and Clank reconciled some of their differences and agreed to work together to stop the weapon. Upon arriving in position to stop the ship, they found it was about to leave, though Ratchet suggested they use an old defense turret to shoot it down before it would be too late.
The Gadgetron vendor now sells the Drone Device, an automated defense system that targets some projectiles and enemies in close proximity to you. Follow the path to the right, where you will encounter a few anklebiters, which mostly serve as fodder. A patch of trees hides an ambush from these creatures by a large number of blarg troopers, but they otherwise provide no real threat. Another smaller group ambushes you from behind a stack of crates near the end of the path. To the right is a flying platform that leads to the path ending at the "Buy Hydro-Pack from Ed". Ignore it for now and instead use the platform to the left.
A device in the floor will dispatch several faster and smaller types of homing mines while you are in its vicinity. Destroy any that appear and run past it, approaching a blarg heli-commander that will begin to unload a barrage of rockets. The Devastator is a recommended weapon to use against him. Continue on another platform, and you will encounter another group of troopers that rush forwards to halt your progress. Another commander appears shortly after, after which you can use the wall to wall-jump to reach the top. Keep following the linear route, but be mindful of a conveyor belt that leads you directly into another homing mine dispenser and a few anklebiters that hide within the snow of the second tunnel.
A trio of floating platforms will lead you to a large building. Two troopers emerge from the entrance while a large group of them will wait inside. Once defeated, exit through the rear entrance and approach the turret. A lone commander will attempt to block your path but likely proves futile. Once you take control of the turret, it must be used to shoot down the ship carrying the bomb. The ship is protected by five turrets and a continuously respawning group of blarg heli-commanders. You should focus heavily on shooting down the heli-commanders if their numbers get too high, as the turrets on the ship do not focus fire on you. At the same time, focus on shooting down the ship. As you continue to do so, parts of the ship will fall off, an indicator as to how close you are to destroying it. After completing the mission, simply glide down from the platform you are on to reach your ship.