Thrusters are the output point of the engine chain, using hydrogen gathered from the intakes and energy from the engine to provide the actual thrust that moves a spacecraft. They modify the overall engine output, burn at different rates, impact the range, and increase or decrease the radar profile of the ship.
- Main engine thrust: Typically provided by the largest and most powerful units, these thrusters, typically mounted at the aft of the ship, provide forward thrust.
- Retro thrust: Reverse thrust used to slow or stop a spacecraft, provided typical by thrusters mounted near the bow.
- Maneuvering thrust: Thrust used to change the spacecraft's orientation and overall vector.
- Maneuvering thrusters mounted near the bow of a ship typically also provide retro thrust when needed.
Main article: Thrust Rating
A thruster's rating is a number between one and ten that reflects its size and power. A 1-rated thruster typically serves as a maneuvering or retro thruster on the smallest ships, while a 10-rated thruster would provide main engine thrust for a cruiser.
A spacecraft has thruster slots that are intended for a thruster of a specific rating, but the rating of a thruster slot is the maximum rating of thruster that can be mounted there. A thruster slot can also accept thrusters with a lower rating.
Most spacecraft, at a minimum, have one slot for a main engine thruster that is two ratings higher than the slots for maneuvering thrusters, of which there will generally be no less than four. More commonly, a spacecraft will have at least eight thrusters, and may provide at least a few main engine thruster slots.
A thruster's articulation type refers to its ability to rotate and/or redirect its thrust, and the available types are:
- Fixed: Cannot rotate or redirect its thrust; always provides thrust in the direction it was mounted.
- Jointed: Rigid thrusters that can rotate along either one axis or two.
- Flex: Non-rigid thrusters that can rotate along either one or two axes.
- Vectored: Thrusters with rotating flaps that can redirect the thrust.
The Hornet, as a example, has a single 4-rated vectored main engine thruster, four 2-rated flex maneuvering thrusters on the top, and four 2-rated jointed thrusters on the bottom. The two forward thrusters on top and the two on the bottom also provide retro thrust as needed.
Stealth thrusters can provide roughly equal thrust to their equivalent non-silencer versions, but have a reduced plume that results in a lower radar profile. Naturally, these cost more than the equivalent standard thrusters. The F7C-S Hornet Ghost is a Hornet alternative equipped with a stealth thruster.