Normal-space propulsion system.
— In-Game Description
Thrusters are what propels a ship when flying in normal space. Upgraded thrusters can accommodate heavier ships, increase ship speed and improve manoeuvrability. If the Optimal Mass of a ship is exceeded, it will be unable to travel at its top speed until its mass is lowered below the Optimal Mass threshold.
Theory based on player-gathered data
A ship's top speed is based on the ratio of optimal mass of the equipped thrusters to the total mass of the ship. This ratio is only linear in the case of C-rated thrusters. A- & B-rated thrusters are positively concave, meaning that they benefit more from a total mass lower than optimal mass and have less of a disadvantage from a total mass higher than optimal mass. D- & E-rated thrusters have the opposite effect.
At a total mass identical to the optimal mass of the equipped thrusters, a ship's top speed will always be identical to the advertised speed, no matter the rating. This does not mean that a higher rated thrusters won't have a benefit over lower ratings, as they have a higher optimal mass.
Power Distributor rating and class appears to have no effect on top speed (outside of it's mass), but the number of pips allocated to engines do. Top speed per pip allocated is a linear function, meaning that 2 pips will have a speed exactly between 4 pips and 0 pips, but the speed modifier of 0 allocated pips depends on a hidden value belonging to the ship, as can be seen in the table below.
|Federal Assault Ship||0.710|
Thruster effect on ship agility in the form of pitch, yaw & roll speed as well as acceleration has yet to be determined.
The following modifications can be applied to this module by Engineers to enhance its abilities:
The following experimental effects can be applied to this module:
The main thruster(s) obviously push the ship forward, but generally also have flaps to redirect thrust or are even capable of being swiveled and re-pointed, which allows them also to control the direction of the ship. However all ships have multiple smaller thrusters situated in relevant locations over their hull: these are the manoevering thrusters, and allow for more refined directional changes.
Manoeuvering thrusters fire automatically in response of the pilot's stick movements. Pilots will see them as small jets emitting from points along their ship as they move the stick. Turning off Flight Assist will give the manoeuvering thrusters more control over the ship's orientation at the cost of less control over its forward motion.
The force applied by the manoeuvering thrusters relative to the ship mass is used to specify a ship's manoeverability rating, but there are exceptions. It is assumed that upgrading thrusters also upgrades manoeuvering capability, but the effect has not yet been quantified.
Although they are clearly based on a real physical model, the individual manoeuvering thrusters or arrays were never named by any official publication from Frontier Developments, but in a simplified way they can be labeled by their real-life equivalents.
Retro (or reverse) thrusters are those which act in the opposite direction than the main thruster, causing a "braking" effect. Some ships are known for their retros being weak compared to their main thrust (such as the Asp Explorer). Pilots in such ships need to take especial care not to collide at high speed with objects such as stations, especially after boosting. Conversely, strong retro thrusters (such as on the Mamba) allow a pilot to reverse in the face of an oncoming target keep all front-mounted hardpoint weapons on them, and even to decelerate suddenly and allow a pursuer to overshoot and become pursued himself.
The lateral thrusters are those on the flanks of a ship and push it port and starboard in space. They are most significant when landing gear are deployed, although they do assist in changing the ship's yaw. If the lateral thrusters are powerful enough, a ship can turn all the way to face the opposite direction of its previous travel without pitching or rolling, but this is generally only practical in some of the most nimble combat ships.
Dorsal thrusters, on the "top" and ventral thrusters on the "belly" of the ship are used to roll and pitch the ship. These tend to be the most important for nimbleness, especially in combat. Ventral thrusters are also used to hover and to therefore to land; weak ventral thrusters can make landings slower, or even (in the case of high gravity bodies) more difficult and dangerous.
It is a common misconception that air resistance is responsible for slowing ships when landing gear is engaged, but in reality it is due to main thruster power being redirected to the manoeuvering thrusters. When landing gear is engaged, a ship can move freely in every direction without changing orientation, but not very quickly.