In Starfield, your entire ship is powered by one part—the reactor. A reactor is simply a battery, and the more powerful your reactor, the more powerful other parts of your ship can be. There are dozens of different reactors to choose from, and picking the right one is essential to optimizing your ship’s quality.
Reactors can be changed out through the Ship Builder menu, regardless of whether a ship was custom-built or purchased. Upgrading a reactor will in turn allow for all other ship modules to be upgraded.
Starfield ship reactors explained
If you already know all the inner workings of reactors, use the table of contents to jump ahead. If not, read on, as the categories and limitations of reactors matter greatly when selecting which one is best for your ship.
Reactors are split up into three categories in Starfield—Class A, Class B, and Class C. Class A reactors generally provide the least amount of power, and Class C reactors provide the most. This does not simply mean you should always purchase Class C reactors, however.
In Starfield, you must acquire rank three of the skill Piloting in the Tech tree before you can fly ships with a Class B reactor, and rank four of Piloting is required to fly Class C ships. Because of this, your level and skill point distribution matters greatly when deciding on your reactor; buying a Class C ship when you don’t have any skill points in Piloting would be a complete waste of Credits, as you would need to level up at least four times before you could actually use that ship.
Piloting isn’t the only skill that determines your building options. While anyone with rank four of Piloting can fly Class C ships, they can’t necessarily build Class C ships worthy of their rank. Reactors have rarity tiers just like all other items in Starfield, and you’ll need to rank up the skill Starship Design before you can access high-rarity modules in Ship Builder.
The Best Class A reactor in Starfield
Because of the skill requirements for higher reactor classes, it is very common that a player will not need to know the objective best reactor in Starfield, but rather the best reactor accessible to everyone with no prerequisites.
With that criteria in mind, the best Class A reactor is:
360 Stellarator Reactor
This reactor can be purchased from the Shipyard Vendor in New Atlantis for 17,600 Credits. The reactor offers 20 power—the most you’ll get out of a Class A reactor without being a very high level and fully upgrading the Starship Design skill. If your goal is to avoid prerequisites, this is the perfect option.
| Reactor | Class | Power Generated | Reactor Health | Hull | Crew Capacity | Required Skills: |
| 360T Stellerator | A | 20 | 32 | 440 | One | N/A |
The Best Class B reactor in Starfield
If you ask me, once you’ve put three points into piloting, it is completely worth it to dish out the one extra point to unlock Class C reactors. With that said, you will inevitably have a period between levels where that isn’t possible yet, and a ship enthusiast may still want to fully optimize their ship during that time by selecting the best Class B reactor available.
With that said, if you’re also willing to put some points into Starship Design, a fantastic Class B reactor becomes available.
With no prerequisites other than rank three of Piloting (no points in Starship Design), the best Class B Reactor you can get is:
Z-Machine 2000 Reactor
This reactor offers 21 power—only one more than the best Class A reactor. However, it does offer more crew capacity, more health, and a significantly faster repair rate.
Even with those bonuses, I’d say put an extra point into Piloting to unlock Class C reactors or put three points into Starship Design to unlock additional Class B options. At rank three of Starship Design, the true best Class B reactor is available.
Z-Machine 3000 Reactor
This generator is a step up from its 2000 counterpart in every way possible. It offers 28 power and an improvement in Health, Hull, and Crew Capacity. You will need to put three points into Starship Design to add this reactor to any ship, but if you’re serious about shipbuilding, Starship Design is already a must-have skill.
| Reactor | Class | Power Generated | Reactor Health | Hull | Crew Capacity | Required Skills: |
| Z-Machine 2000 | B | 21 | 57 | 610 | Two | Piloting (Rank three) |
| Z-Machine 3000 | B | 28 | 65 | 890 | Two | Piloting (Rank three) Starship Design (Rank three) |
The Best Class C reactor in Starfield
Class C is the absolute best reactor class in Starfield, and these reactors can power any other module while offering significantly more overall power to be distributed across your ship’s other systems. Most Class C reactors are going to also need skill points in Starship Design, which allows you to install rare/unique parts into your ship. If you want to access the true best of the best reactors, you’ll need to rank four of both Piloting and Starship Design.
SF40 Sheard Flow
This reactor is an absolute bear that can power any ship with ease, as it grants 40 power. You’ll need to be level 57 before it can be acquired, and you’ll also need to have fully advanced Piloting and Starship Design.
But hey, you’re after the best of the best—what did you expect?
| Reactor | Class | Power Generated | Reactor Health | Hull | Crew Capacity | Required Skills: |
| SF40 Sheard Flow | C | 40 | 116 | 1315 | Three | Piloting (Rank four) Starship Design (Rank four) |
Once you are able to fly Class C ships by putting four points into Piloting, definitely put points into Starship Design. Piloting allows you to fly these higher-ranked ships, but Starship Design is what allows you to install higher-rarities modules. You can fly a Class C ship that already has rare parts on it, but only if you found or purchased it that way.
If you want to add rare reactors, weapons, grav drives, or shield generators to your ships via Ship Builder, then Starship Design is just as important as Piloting.
