Difference between revisions of "Reaction engine"

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m (→‎Solid fuel rocket engines: !link to solid rocket booster;)
(+ion engine; +RCS thrusters; *moved text into their designated sections; +physical principle;)
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[[Image:LV-T30_Liquid_Fuel_Engine.jpg|right|thumb|[[LV-T30 Liquid Fuel Engine]]]]
 
[[Image:LV-T30_Liquid_Fuel_Engine.jpg|right|thumb|[[LV-T30 Liquid Fuel Engine]]]]
  
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A '''rocket engine''' is an engine that uses nothing but its onboard propellant to generate thrust. Unlike traditional air breathing engines used by atmospheric crafts rocket engines are able to function in a vacuum where no oxygen is present.
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A '''rocket engine''' is an [[engine]] that uses nothing but its onboard propellant to generate thrust. Unlike traditional air breathing [[jet engine]]s rocket engines are able to function where no oxygen is present.
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== History ==
 
−
 
 
−
Rocket engines were present in KSP in all public releases of the game.
 
  
 
== Approaches to rocket engines ==
 
== Approaches to rocket engines ==
 +
All rocket engine work with the same principle: They propel mass out of nozzles and accelerate because of Newton's third law of motion. The difference to jet engines is that they don't need a surrounding atmosphere. They also don't need any surface which allows them to be used everywhere.
  
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Rocket engines come in two commonly used forms. The first and most ancient type is a [[solid fuel]] rocket which is as simple as igniting a solid, self-oxidizing compound or mixture within the casing of the rocket and allowing the escaping gases to be released through a nozzle at the rear. There are currently two booster rocket sizes included.
+
There are four different types available in the game which all use this basic principle. Apart from RCS thrusters their controls are the same.
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Liquid fuel engines are powered by a liquid propellant which is comprised of combustible [[liquid fuel]] and [[oxidizer]]. In the real world typical liquid fuels are often liquid hydrogen or kerosene, and typical oxidizers are liquid oxygen or nitrous-oxide. All engines use [[w:Bell nozzle|Bell nozzles]] except the only [[w:Aerospike engine|aerospike engine]].
 
  
 
== Solid fuel rocket engines ==
 
== Solid fuel rocket engines ==
 
:→ Main article: [[Solid rocket booster]]
 
:→ Main article: [[Solid rocket booster]]
 +
The most ancient type is a [[solid fuel]] rocket which is as simple as igniting a solid, self-oxidizing compound or mixture within the casing of the rocket and allowing the escaping gases to be released through a nozzle at the rear.
 +
 
=== Advantages ===
 
=== Advantages ===
  
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== Liquid fuel rocket engines ==
 
== Liquid fuel rocket engines ==
 +
Liquid fuel engines are powered by a liquid propellant which is comprised of combustible [[liquid fuel]] and [[oxidizer]]. In the real world typical liquid fuels are often liquid hydrogen or kerosene, and typical oxidizers are liquid oxygen or nitrous-oxide. All engines use [[w:Bell nozzle|Bell nozzles]] except the only [[w:Aerospike engine|aerospike engine]].
 +
 
=== Advantages ===
 
=== Advantages ===
  
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* Complex design with fuel tanks and other additional components.   
 
* Complex design with fuel tanks and other additional components.   
 
* More points of possible failure such as if the parts tear apart from stress.
 
* More points of possible failure such as if the parts tear apart from stress.
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{{FlipBox
 
{{FlipBox
 
|title=Available liquid fuel rocket engines
 
|title=Available liquid fuel rocket engines
 
|content={{Stats Table Liquid Fuel Engines}}
 
|content={{Stats Table Liquid Fuel Engines}}
 +
}}
 +
 +
== Ion engines ==
 +
There is a new third form called ion engine which uses ionized atoms, [[xenon gas]], and accelerate them in a electro-magnetic field. This type of engine is very efficient but has a very low thrust making it only suitable for probes already in space.
 +
 +
=== Advantages ===
 +
* A very high specific impulse.
 +
* The [[xenon gas]] can be moved between tanks, which means that spacecraft with ion engines and tanks are easier and more resource-efficient to refuel than vessels with solid fuel engines, which required the entire engine bay to be replaced, while xenon gas can quickly be moved between two docked vessels.
 +
* The fuel doesn't need to be moved as xenon gas is used evenly.
 +
* Modular design: fuel and other components can be stored elsewhere in the craft.
 +
* Throttle can be adjusted depending on thrust requirements.
 +
* Can be switched off and re-ignited at will.
 +
=== Disadvantages ===
 +
* Very low thrust so it is impossible to lift off with ion engines only.
 +
* No thrust vectoring is available.
 +
 +
{{FlipBox
 +
|title=Available ion engine parts
 +
|content={{Stats Table Xenon}}
 +
}}
 +
 +
== RCS thrusters ==
 +
The [[RCS]] thrusters are allowing an craft to change the attitude, because their thrust is low allowing tiny changes in velocity. Usually it isn't used as a main engine because the specific impulse is lower than any other liquid fuel engine.
 +
 +
=== Advantages ===
 +
* The [[monopropellant]] can be moved between tanks, which means that spacecraft with RCS thrusters and tanks are easier and more resource-efficient to refuel than vessels with solid fuel engines, which required the entire engine bay to be replaced, while xenon gas can quickly be moved between two docked vessels.
 +
* The fuel doesn't need to be moved as monopropellant is used evenly.
 +
* Modular design: fuel and other components can be stored elsewhere in the craft.
 +
* Can be switched off and re-ignited at will.
 +
=== Disadvantages ===
 +
* Very low thrust so it is impossible to lift off with ion engines only.
 +
* No thrust vectoring is available.
 +
* The user can only switch engines on or off, while the SAS can run them on different thrust levels in between.
 +
* The specific impulse is, especially in atmosphere, low and comparable with solid rocket engines.
 +
 +
{{FlipBox
 +
|title=Available RCS engines
 +
|content={{Stats Table RCS Thrusters}}
 
}}
 
}}
  
 
{{Parts}}
 
{{Parts}}
 +
[[Category:Engine]]

Revision as of 18:17, 5 July 2013

LV-T30 Liquid Fuel Engine

A rocket engine is an engine that uses nothing but its onboard propellant to generate thrust. Unlike traditional air breathing jet engines rocket engines are able to function where no oxygen is present.

Approaches to rocket engines

All rocket engine work with the same principle: They propel mass out of nozzles and accelerate because of Newton's third law of motion. The difference to jet engines is that they don't need a surrounding atmosphere. They also don't need any surface which allows them to be used everywhere.

There are four different types available in the game which all use this basic principle. Apart from RCS thrusters their controls are the same.

Solid fuel rocket engines

→ Main article: Solid rocket booster

The most ancient type is a solid fuel rocket which is as simple as igniting a solid, self-oxidizing compound or mixture within the casing of the rocket and allowing the escaping gases to be released through a nozzle at the rear.

Advantages

  • Have a very high thrust to weight ratio.
  • Engine and fuel tank are combined in one part, lowering part count, simplifying design and improving stability, which is especially important in the early stages of a rocket launch from the surface of a planet where large ammounts of more or less heavy parts and high-powered rockets cause stress both to the vessel itself and the player's computer.

Disadvantages

  • Monolithic design, must be built in one piece.
  • Cannot be throttled or switched off after ignition.
  • Once spent, they are unable to use fuel from another source of the craft.
Available solid fuel rocket engines
Solid Fuel Density is 7.5 kg/unit Mass
(t) 		Fuel
(Units of fuel) 		Thrust
(kN) 		TWR Isp (s) Burn
(s)
Full Empty
Image Part Radial size Cost
(Funds)		 Full Empty Max. Temp.
(K)		 Tolerance
(m/s)		 Tolerance
(g) 		atm vac atm vac atm vac atm vac
RT-5 White.png
 RT-5 "Flea" Solid Fuel Booster Small, Radial mounted 200
(116) 		1.50 0.45 2 000 7 50 140 162.91 192.0 11.07 13.05 36.92 43.51 140 165 8.8
RT-10 White.png
 RT-10 "Hammer" Solid Fuel Booster Small, Radial mounted 400
(175) 		3.56 0.75 2 000 7 50 375 197.90 227.0 5.66 6.50 26.91 30.86 170 195 23.7
BACC SFB.png
 BACC "Thumper" Solid Fuel Booster Small, Radial mounted 850
(358) 		7.65 1.50 2 200 7 50 820 250.00 300.0 3.33 4.00 17.00 20.39 175 210 42.2
SRB.png
 S1 SRB-KD25k "Kickback" Solid Fuel Booster Small, Radial mounted 2 700
(1 140) 		24.00 4.50 2 200 7 50 2 600 593.86 670.0 2.52 2.85 13.46 15.18 195 220 62.8
Sepratron.png
 Sepratron I Radial mounted 75
(70.2) 		0.0725 0.0125 2 000 7 50 8 13.79 18.0 19.40 25.32 112.51 146.84 118 154 5.0
Mite.png
 FM1 "Mite" Solid Fuel Booster Tiny, Radial mounted 75
(51.0) 		0.375 0.075 2 200 7 50 40 11.012 12.5 2.93 3.33 14.68 16.66 185 210 49.44
Shrimp.png
 F3S0 "Shrimp" Solid Fuel Booster Tiny, Radial mounted 150
(96.0) 		0.875 0.155 2 200 7 50 90 26.512 30.0 3.22 3.65 17.1 19.35 190 215 47.44
Thorougbred.png
 S2-17 "Thoroughbred" Solid Fuel Booster Large, Radial mounted 9 000
(4 200.0) 		70.00 10.00 2 200 10 50 8 000 1 515.217 1 700.0 2.16 2.43 15.15 17.0 205 230 79.6
Clydesdale.png
 S2-33 "Clydesdale" Solid Fuel Booster Large, Radial mounted 18 500
(8 660.0) 		144.00 21.00 2 200 10 50 16 400 2 948.936 3 300.0 2.05 2.29 14.04 15.71 210 235 85.9

Liquid fuel rocket engines

Liquid fuel engines are powered by a liquid propellant which is comprised of combustible liquid fuel and oxidizer. In the real world typical liquid fuels are often liquid hydrogen or kerosene, and typical oxidizers are liquid oxygen or nitrous-oxide. All engines use Bell nozzles except the only aerospike engine.

Advantages

  • Fuel and oxidizer can be moved between liquid fuel tanks, which means that spacecraft with liquid fuel engines and fuel tanks are easier and more resource-efficient to refuel than vessels with solid fuel engines, which required the entire engine bay to be replaced, while liquid fuel and oxidizer can quickly be moved between two docked vessels.
  • Modular design: fuel and other components can be stored elsewhere in the craft.
  • Throttle can be adjusted depending on thrust requirements.
  • Can be switched off and re-ignited at will.
  • Many nozzles can be gimballed for thrust vectoring.
  • Efficiency largely dependent on design, with large variations. For early stages, high-output engines with low fuel-efficiency can be used to reach a low Kerbin orbit, while extremely efficient but low-power engines should be used for travelling between planets and moons to save fuel and extend the range of the craft.

Disadvantages

  • Lower power to weight ratio compared to solid rocket engines.
  • Complex design with fuel tanks and other additional components.
  • More points of possible failure such as if the parts tear apart from stress.
Available liquid fuel rocket engines
Thrust
(kN) 		T/W
ratio 		Max. Fuel
Consumption
(Units of fuel/s) 		Isp (s) TVC
Image Part Radial size Cost
(Funds)		 Mass
(t)		 Max. Temp.
(K)		 Tolerance
(m/s)		 Tolerance
(g) 		atm vac atm vac atm vac Gimbal
(°)
LV-1R Shroud.png
 LV-1R "Spider" Liquid Fuel Engine Radial mounted 120 0.02 2 000 7 50 1.79 2.0 9.14 10.20 0.141 260 290 10.0
24-77 Orange.png
 24-77 "Twitch" Liquid Fuel Engine Radial mounted 230 0.08 2 000 7 50 15.17 16.0 19.34 20.39 1.125 275 290 8.0
Mk-55 Radial mount engine.png
 Mk-55 "Thud" Liquid Fuel Engine Radial mounted 820 0.90 2 000 7 50 108.20 120.0 12.26 13.60 8.024 275 305 8.0
O-10.png
 O-10 "Puff" MonoPropellant Fuel Engine[Note 1] Radial mounted 150 0.09 2 000 7 50 9.60 20.0 10.88 22.66 2.039 120 250 6.0
LV-1 Shroud.png
 LV-1 "Ant" Liquid Fuel Engine Tiny, Radial mounted 110 0.02 2 000 7 50 0.51 2.0 2.59 10.20 0.129 80 315 —
48-7S Shroud.png
 48-7S "Spark" Liquid Fuel Engine Tiny 240 0.13 2 000 7 50 16.56 20.0 12.99 15.69 1.275 265 320 3.0
LV-909 Shroud.png
 LV-909 "Terrier" Liquid Fuel Engine Small 390 0.50 2 000 7 50 14.78 60.0 3.01 12.24 3.547 85 345 4.0
LV-T30 Liquid Fuel Engine recent.png
 LV-T30 "Reliant" Liquid Fuel Engine Small 1 100 1.25 2 000 7 50 205.16 240.0 16.74 19.58 15.789 265 310 —
LV-T45 LFE.png
 LV-T45 "Swivel" Liquid Fuel Engine Small 1 200 1.50 2 000 7 50 167.97 215.0 11.42 14.62 13.703 250 320 3.0
KS-25 LFE.png
 S3 KS-25 "Vector" Liquid Fuel Engine Small, Radial mounted 18 000 4.00 2 000 22 50 936.51 1 000.0 23.87 25.49 64.745 295 315 10.5
ToroidalAerospikeLiquidFuelEngine.png
 T-1 Toroidal Aerospike "Dart" Liquid Fuel Engine Small, Radial mounted 3 850 1.00 2 000 20 50 153.53 180.0 15.66 18.35 10.797 290 340 —
LV-N Atomic.png
 LV-N "Nerv" Atomic Rocket Motor[Note 2] Small 10 000 3.00 2 500 12 50 13.88 60.0 0.47 2.04 1.530 185 800 —
RE-L10.png
 RE-L10 "Poodle" Liquid Fuel Engine Large 1 300 1.75 2 000 7 50 64.29 250.0 3.75 14.57 14.568 90 350 4.5
SkipperV2.png
 RE-I5 "Skipper" Liquid Fuel Engine Large 5 300 3.00 2 000 8 50 568.75 650.0 19.33 22.09 41.426 280 320 2.0
MainsailV2.png
 RE-M3 "Mainsail" Liquid Fuel Engine Large 13 000 6.00 2 000 7 50 1 379.03 1 500.0 23.44 25.49 98.683 285 310 2.0
LFB KR-1x2.png
 LFB KR-1x2 "Twin-Boar" Liquid Fuel Engine[Note 3] Large, Radial mounted 17 000
(14 062.4) 		42.50
(10.50) 		2 000 20 50 1 866.67 2 000.0 4.48
(18.13) 		4.80
(19.42) 		135.964 280 300 1.5
Big1.png
 Kerbodyne KR-2L+ "Rhino" Liquid Fuel Engine Extra large 25 000 9.00 2 000 7 50 1 205.88 2 000.0 13.66 22.66 119.968 205 340 4.0
Quad.png
 S3 KS-25x4 "Mammoth" Liquid Fuel Engine Extra large 39 000 15.00 2 000 20 50 3 746.03 4 000.0 25.47 27.19 258.978 295 315 2.0
Rapier Engine 01.png
 CR-7 R.A.P.I.E.R. Engine[Note 4] Small 6 000 2.00 2 000 20 50 162.30 180.0 8.27 9.18 12.036 275 305 3.0
  1. ↑ Consumes monopropellant. (the density of monopropellant is less: 4kg/unit)
  2. ↑ Consumes liquid fuel only.
  3. ↑ The LFB KR-1x2 is a liquid fuel booster -- a combination of a "normal" engine and a fuel tank.
  4. ↑ The R.A.P.I.E.R. Engine is a combination of liquid fuel and jet engine. Only the liquid fuel engine properties are shown.

Ion engines

There is a new third form called ion engine which uses ionized atoms, xenon gas, and accelerate them in a electro-magnetic field. This type of engine is very efficient but has a very low thrust making it only suitable for probes already in space.

Advantages

  • A very high specific impulse.
  • The xenon gas can be moved between tanks, which means that spacecraft with ion engines and tanks are easier and more resource-efficient to refuel than vessels with solid fuel engines, which required the entire engine bay to be replaced, while xenon gas can quickly be moved between two docked vessels.
  • The fuel doesn't need to be moved as xenon gas is used evenly.
  • Modular design: fuel and other components can be stored elsewhere in the craft.
  • Throttle can be adjusted depending on thrust requirements.
  • Can be switched off and re-ignited at will.

Disadvantages

  • Very low thrust so it is impossible to lift off with ion engines only.
  • No thrust vectoring is available.
Available ion engine parts
Template:Stats Table Xenon

RCS thrusters

The RCS thrusters are allowing an craft to change the attitude, because their thrust is low allowing tiny changes in velocity. Usually it isn't used as a main engine because the specific impulse is lower than any other liquid fuel engine.

Advantages

  • The monopropellant can be moved between tanks, which means that spacecraft with RCS thrusters and tanks are easier and more resource-efficient to refuel than vessels with solid fuel engines, which required the entire engine bay to be replaced, while xenon gas can quickly be moved between two docked vessels.
  • The fuel doesn't need to be moved as monopropellant is used evenly.
  • Modular design: fuel and other components can be stored elsewhere in the craft.
  • Can be switched off and re-ignited at will.

Disadvantages

  • Very low thrust so it is impossible to lift off with ion engines only.
  • No thrust vectoring is available.
  • The user can only switch engines on or off, while the SAS can run them on different thrust levels in between.
  • The specific impulse is, especially in atmosphere, low and comparable with solid rocket engines.
Available RCS engines
Image Part Radial size Cost
(Funds)		 Mass
(t)		 Max. Temp.
(K)		 Tolerance
(m/s)		 Tolerance
(g) 		Thrust
(kN) 		Fuel
(Units of fuel/s) 		Isp (s) (atm) Isp (s) (vac)
RV-1X.png
 RV-1X Variable Thruster Block Radial mounted 30 0.005 1 500 12 50 0.1 0.01 100 240
PlaceAnywhere1.png
 Place Anywhere 1 Linear RCS Port Radial mounted 15 0.001 1 500 12 50 0.2 0.02 100 240
RV-105.png
 RV-105 RCS Thruster Block Radial mounted 45 0.04 1 500 15 50 1.0 0.11 100 240
Linear RCS.png
 Place-Anywhere 7 Linear RCS Port Radial mounted 25 0.02 2 600 15 50 2.0 0.21 100 240
Vernor.png
 Vernor Engine[Note 1] Radial mounted 150 0.08 2 000 15 50 12.0 0.94 140 260
  1. ↑ The Vernor Engine uses a liquid fuel/oxidizer mixture.
 
Manned pods
Command seats
Probe cores
 
Liquid fuel tanks
Monopropellant fuel tanks
Jet fuselages
Fuel transfers
Xenon containers
Ore tanks
 
Jet engines
Liquid fuel engines
Solid fuel rockets
Monopropellant engines
Ion engines
 
RCS thrusters
Reaction wheels
SAS modules
 
Beams, panels and radial elements
Launch assistance
Stackable elements
 
Decouplers
Separators
Claws
Docking ports
 
Fairings
Cargo bays
Service bays
 
Air intakes
Control surfaces
Modular wings
Nose cones
Static wings
Tail connectors
Winglets
 
Landing struts
Landing gears
Rover wheels
 
Heat shields
Radiators
 
Fuel cell
Generators
Batteries
 
Direct Antennae
Relay Antennae
 
Sensors
Labs
Telescopes
Resource scanners
Storages
 
Storages
Equipment
Deployables
 
Parachutes
Ladders
Lamps
Escape systems
Habitation modules
Resource harvesters
Ore processing
Flags
Fireworks
 
Command modules
Fuel Tanks
Decouplers
Separators
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