Difference between revisions of "LV-N "Nerv" Atomic Rocket Motor"

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(Usage: doesn't overheat nowadays)
 
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{{:LV-N Atomic Rocket Motor/Box}}
 
{{:LV-N Atomic Rocket Motor/Box}}
  
The '''LV-N Atomic Rocket Motor''' is a low-thrust, high-efficiency [[rocket engine]]. It is modeled after the real-world [[wikipedia:nuclear thermal rocket|nuclear thermal rocket]], which uses a fission reactor to heat liquid hydrogen and propel it out of the rocket nozzle; however, as of {{Check version|0.24}}, it is still a hybrid design which is powered by [[liquid fuel]] and [[oxidizer]]. This is largely due to programming constraints, as stated in its parts.cfg file, although the real-world equivalent could use other liquids for propulsion, but then with a lower efficiency.
+
The '''LV-N "Nerv" Atomic Rocket Motor''' is a low-thrust, high-efficiency [[rocket engine]]. It is modeled after the real-world theoretical [[wikipedia:nuclear thermal rocket|nuclear thermal rocket]], which uses a fission reactor to heat its propellant and force it out of the rocket nozzle to generate thrust (as opposed to a normal rocket, which ignites the propellant and uses the energy released by the resulting chemical reaction for that purpose).
  
 
== Usage ==
 
== Usage ==
The LV-N has a quite low thrust (the [[LV-909 Liquid Fuel Engine|LV-909]] being the only engine in its size-class with less power) and with 2.25 tons a very high mass, giving it the worst [[thrust-to-weight ratio]] of all liquid-fuel engines. Its fuel efficiency while in the atmosphere is also rather poor. Due to those factors it is not recommended to use this engine to escape atmosphere or even the gravity of large moons.
+
The LV-N has low thrust and a very high mass, giving it the worst [[thrust-to-weight ratio]] of all liquid engines. For this reason, it is a very poor choice for propulsion in skycranes, despite its high vacuum specific impulse. Its [[Isp|I<sub>sp</sub>]] while in atmosphere is also quite poor, making it not recommended for operation within atmospheres or for landings on larger bodies.
  
But as soon as it gets out of the atmosphere, its fuel efficiency becomes superb with a vacuum [[Specific impulse|I<sub>sp</sub>]] of 800 s. The best specific impulse of any liquid-fueled engine. Only the non liquid fueled [[PB-ION Electric Propulsion System]] is better but with even less thrust. This remarkable efficiency makes it quite popular for interplanetary travel.
+
However, when outside the atmosphere, its efficiency becomes superb with a vacuum [[Specific impulse|I<sub>sp</sub>]] of 800 s, by far the highest of any [[liquid engine|liquid fuel engine]]. This remarkable efficiency makes it quite popular for upper stages as it is ideal for interplanetary travel.  With the 1.0 update, this engine '''consumes only liquid fuel.'''  As such, it is much more mass-efficient to build your craft with tanks that only contain liquid fuel and no oxidizer.
  
It will overheat, but it will usually stop at about ⅓ through the overheat bar. As of version 0.23, it will quickly overheat and explode when placed under a [[Rockomax Jumbo-64 Fuel Tank]].
+
In early (which?) versions of the game, this engine used to [[Overheating|overheat]] when run at full throttle for the long burns typical of nuclear-powered craft (though it usually stabilized before completely filling the overheat bar) but this is no longer the case and very long burns can be performed without fear of overheating. It is quite long, being almost exactly the same length as a Mainsail engine. LV-N engines on a landing stage require some interesting structure designs to get the landing gear low enough to clear the bottom of the engine.
  
== Description ==
+
== Product description ==
 
{{Quote
 
{{Quote
|Despite the big scary trefoil painted onto the side of this engine, its radioactive exhaust, and tendency to overheat, the LV-N Atomic Rocket Motor is harmless. Mostly.
+
|Despite the big scary trefoil painted onto the side of this engine, its radioactive exhaust, and tendency to overheat, the LV-N Atomic Rocket Motor is harmless. Mostly. Note that the LV-N is the only LV series engine to run solely on Liquid Fuel - the future is glowing bright!
|Jebediah Kerman's Junkyard and Spaceship Parts Co.}}
+
}}
  
{{Quote|Yes, I know this is wrong. NTRs don't actually burn fuel and oxidizer, but we don't want to jump into making separate tanks for the two yet.|Excerpt from the part.cfg}}
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{{Quote|Yes, I know this is wrong. NTRs don't actually burn fuel and oxidizer, but we don't want to jump into making separate tanks for the two yet.|Excerpt from the part.cfg pre-[[1.0]]}}
  
 
== Trivia ==
 
== Trivia ==
* The description of this part is a reference to the Douglas Adams humorous sci-fi novel "Mostly Harmless"
+
* The description of this part contains a reference to Douglas Adams' ''Hitchhiker's Guide to the Galaxy'' series, in which the Earth is described as "mostly harmless".
 +
* Before [[1.0]], the LV-N consumed both [[liquid fuel]] and [[oxidizer]], unlike real-world nuclear thermal rockets. This due to programming constraints, as stated in its parts.cfg file, and [[Squad]]'s unwillingness to add another tank type. Real NTRs run on liquid hydrogen, but are capable of using other propellants at lower efficiencies.  With the addition of liquid-fuel-only tanks for spaceplanes, this constraint vanished.
 +
* Interestingly, the LV-N has two shrouds, one for each half of the engine. Both are toggleable in the editor.
 +
* The "Nerv" nickname is likely a reference to [[w:NERVA|NERVA]], or "Nuclear Engine for Rocket Vehicle Application", a NASA program to create a nuclear thermal rocket.
  
 
== Changes ==
 
== Changes ==
;{{Version|0.24|}}
+
;[[1.0]]
 +
* LV-N “Nerv” Engine now runs solely on Liquid Fuel.
 +
* No longer has a gimbal.
 +
* Cost increased to 10000.
 +
* Mass increased from 2.25 to 3.
 +
* Isp curve extended past 1 atmosphere; Isp drops to 0.001 at 2 atm.
 +
;[[0.24]]
 
* Cost increased from 1700 to 8700 (and made meaningful)
 
* Cost increased from 1700 to 8700 (and made meaningful)
;{{Version|0.22|}}
+
;[[0.22]]
* Alternator added, engine now gains 5.0 electricity.
+
* Alternator added; engine now generates 5.0 electric charge per second.
;{{Version|0.17|}}
+
;[[0.17]]
 
* Initial release
 
* Initial release
  
 
{{Parts}}
 
{{Parts}}
 
[[Category:Liquid fuel engines]]
 
[[Category:Liquid fuel engines]]

Latest revision as of 22:44, 26 January 2019

LV-N "Nerv" Atomic Rocket Motor
Part image
Liquid fuel engine by
Jebediah Kerman's Junkyard and Spacecraft Parts Co
Radial size Small
Cost (total) 10 000.00 Funds
Mass (total) 3.00 t
Drag 0.2
Max. Temp. 2500 K
Impact Tolerance 12 m/s
Research Tech tree nuclear propulsion.png Nuclear Propulsion
Unlock cost 45 000 Funds
Since version 0.17
Part configuration liquidEngineLV-N
Liquid fuel engine
Maximum thrust (1 atm) 13.88 kN
(vacuum) 60.00 kN
Isp (1 atm) 185 s
(vacuum) 800 s
Fuel consumption 1.53 Units of fuel/s


Thrust vectoring × No
Testing Environments
On the surface ✓ Yes
In the ocean × No
On the launchpad × No
In the atmosphere ✓ Yes
Sub orbital ✓ Yes
In an orbit ✓ Yes
On an escape ✓ Yes
Docked × No
Test by staging ✓ Yes
Manually testable ✓ Yes


The LV-N "Nerv" Atomic Rocket Motor is a low-thrust, high-efficiency rocket engine. It is modeled after the real-world theoretical nuclear thermal rocket, which uses a fission reactor to heat its propellant and force it out of the rocket nozzle to generate thrust (as opposed to a normal rocket, which ignites the propellant and uses the energy released by the resulting chemical reaction for that purpose).

Usage

The LV-N has low thrust and a very high mass, giving it the worst thrust-to-weight ratio of all liquid engines. For this reason, it is a very poor choice for propulsion in skycranes, despite its high vacuum specific impulse. Its Isp while in atmosphere is also quite poor, making it not recommended for operation within atmospheres or for landings on larger bodies.

However, when outside the atmosphere, its efficiency becomes superb with a vacuum Isp of 800 s, by far the highest of any liquid fuel engine. This remarkable efficiency makes it quite popular for upper stages as it is ideal for interplanetary travel. With the 1.0 update, this engine consumes only liquid fuel. As such, it is much more mass-efficient to build your craft with tanks that only contain liquid fuel and no oxidizer.

In early (which?) versions of the game, this engine used to overheat when run at full throttle for the long burns typical of nuclear-powered craft (though it usually stabilized before completely filling the overheat bar) but this is no longer the case and very long burns can be performed without fear of overheating. It is quite long, being almost exactly the same length as a Mainsail engine. LV-N engines on a landing stage require some interesting structure designs to get the landing gear low enough to clear the bottom of the engine.

Product description

Despite the big scary trefoil painted onto the side of this engine, its radioactive exhaust, and tendency to overheat, the LV-N Atomic Rocket Motor is harmless. Mostly. Note that the LV-N is the only LV series engine to run solely on Liquid Fuel - the future is glowing bright!
Yes, I know this is wrong. NTRs don't actually burn fuel and oxidizer, but we don't want to jump into making separate tanks for the two yet.

Excerpt from the part.cfg pre-1.0

Trivia

  • The description of this part contains a reference to Douglas Adams' Hitchhiker's Guide to the Galaxy series, in which the Earth is described as "mostly harmless".
  • Before 1.0, the LV-N consumed both liquid fuel and oxidizer, unlike real-world nuclear thermal rockets. This due to programming constraints, as stated in its parts.cfg file, and Squad's unwillingness to add another tank type. Real NTRs run on liquid hydrogen, but are capable of using other propellants at lower efficiencies. With the addition of liquid-fuel-only tanks for spaceplanes, this constraint vanished.
  • Interestingly, the LV-N has two shrouds, one for each half of the engine. Both are toggleable in the editor.
  • The "Nerv" nickname is likely a reference to NERVA, or "Nuclear Engine for Rocket Vehicle Application", a NASA program to create a nuclear thermal rocket.

Changes

1.0
  • LV-N “Nerv” Engine now runs solely on Liquid Fuel.
  • No longer has a gimbal.
  • Cost increased to 10000.
  • Mass increased from 2.25 to 3.
  • Isp curve extended past 1 atmosphere; Isp drops to 0.001 at 2 atm.
0.24
  • Cost increased from 1700 to 8700 (and made meaningful)
0.22
  • Alternator added; engine now generates 5.0 electric charge per second.
0.17
  • Initial release