The Nebula-class starship is capable of mounting several different mission modules. For reasons of warp stability, all Nebula pods are 4 decks tall, and of approximately the same mass.
The ovoid sensor pod was the first module developed for use with the Nebula-class. It has a starship-grade sensor suite, capable of expanding the ship's sensor radius by 10 light years. A disadvantage of this pod is that the high energy sensor sweeps will cause temporary windows where the vessel's shields will be useless. This was exploited by the Enterprise-D to beam aboard the USS Phoenix, while the Phoenix was operating illegally against Cardassian forces. It contains:
- Deck A: Long-Range Sensors
- Deck B: Long-Range Sensors
- Deck C: Module Power Systems and Control Center
- Deck D: Astrometrics Suites, Magnetic Locks, Docking Clamps
The Tactical Module is the most commonly-deployed Nebula module. It expands the vessel's combat capability dramatically, with eight forward-firing torpedo launchers (Type-I Quantum), two aft launchers (Type-I Quantum), magazines for 120 quantum torpedoes and 200 photon torpedoes, an additional three phaser strips (two in the aft groove, firing aft; one running lengthwise on the dorsal surface), andtactical sensor arrays. It contains:
- Deck A: Tactical Sensors Sensors, Dorsal Phaser Array
- Deck B: Torpedo Launchers, Torpedo Magazines
- Deck C: Torpedo Magazines, Module Power Systems and Control Center
- Deck D: Module Shield Systems, Magnetic Locks, Docking Clamps
The Carrier Module expands the Nebula's already-impressive small craft systems, with a through-bay to allow fast launch and retrieval of fighters, shuttles, and runabouts. This module is useful for combat situations (carrying 24 fighters), exploratory situations (carrying 12 runabouts or scouts), and evacuation scenarios (carrying 12 runabouts or other transports). This module also includes dedicated quarters for the officers assigned to these craft.
- Deck A: Small Craft Control Center, Pilot Quarters, Briefing Room
- Deck B: Shuttlebay High Bay
- Deck C: Shuttlebay
- Deck D: Module Power Systems, Magnetic Locks, Docking Clamps
The Cargo Module expands the Nebula's already-impressive cargo-carrying capabilities, with large doors on the ventral surface to carry bulky objects, and smaller cargo bays for other items. It contains its own dedicated transporter systems and cargo elevators.
- Deck A: Cargo Bay Doors, Workbee Storage, Bulk Cargo Bay High Bays
- Deck B: Bulk Cargo Bays
- Deck C: Cargo Bays, Module Power Systems
- Deck D: Cargo Transporters, Magnetic Locks, Docking Clamps