Difference between revisions of "IX-6315 "Dawn" Electric Propulsion System"
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{{:PB-ION Electric Propulsion System/Box}} | {{:PB-ION Electric Propulsion System/Box}} | ||
| − | The ''' | + | The '''IX-6315 "Dawn" Electric Propulsion System''' is a tiny-sized engine which runs on [[electricity]] and [[xenon gas]] propellant. It's modeled after the real-world [[w:Hall effect thruster|Hall effect thruster]]. |
== Usage == | == Usage == | ||
| − | This engine has a phenomenal fuel efficiency (4200 s I<sub>sp</sub>), but very low thrust and requires | + | This engine has a phenomenal fuel efficiency (4200 s I<sub>sp</sub>), but very low thrust and requires a substantial amount of [[electricity]] to operate. Xenon gas is provided by xenon containers like the [[PB-X50R_Xenon_Container|PB-X50R Xenon Container]], [[PB-X150 Xenon Container]] or [[PB-X750 Xenon Container]]. Electricity can be obtained using [[solar panel]]s, [[PB-NUK Radioisotope Thermoelectric Generator|radioisotope batteries (RTGs)]], and [[Fuel cell|fuel cells]]. Solar panels are recommended in this case, however RTGs are very efficient when traveling to far distances such as Jool and Eeloo. The amount of electricity needed to keep one ion engine running at full thrust is roughly equivalent to half the output of one [[Gigantor XL Solar Array]] (however one array will power two engines only near peak sun exposure around Kerbin), 6 [[Fuel Cell]]s, 12 [[PB-NUK Radioisotope Thermoelectric Generator]]s, or 25 [[OX-STAT Photovoltaic Panels]] at peak output. When pairing with solar panels, it is highly recommended to bring more than it needs (slightly less than 9 Ec/s). Not all panels are at peak output during operations, and maximum available power falls of with the square of the distance from the star. |
| − | Batteries can be used to store the electricity since there may be times the solar panels will be blocked from [[Kerbol|the Sun]] by objects or the dark side of [[Celestial body|celestial bodies]]. | + | Batteries can be used to store the electricity since there may be times the solar panels will be blocked from [[Kerbol|the Sun]] by objects or the dark side of [[Celestial body|celestial bodies]]. For extended burns in the darkness the fuel cells happen to be a good choice. When the power is provided by the fuel cells the majority of the mass flow (about 69.2%) is liquid fuel and oxidizer used by the fuel cell. Thus the ion engine powered by the fuel cell may be seen as having much more modest but still impressive effective Isp of 1293 sec. However if the burn doesn't take more than a couple of hours the stack of RTGs providing the same amount of power (and thus thrust) tend to be heavier than the fuel cell array and its fuel tank. The RTGs should be reserved for very long low-thrust burns in the deep space. |
| − | The ion engine is good for fine tuning of orbits. It | + | The ion engine is good for fine tuning of orbits. It was also a popular propulsion method for planes on planets on which [[jet engine]]s don't work, though its current thrust falloff reduces the value there. Due to its great fuel efficiency it is also well-suited for interplanetary travel, but maneuvers tend to take a long time to complete due to its very low [[thrust-to-weight ratio]] -- it is advised to use it for very small craft, and to use [[Time warp#Physical Time Warp|physics-warp]] while propelling with it. Usually the engine is used on long range craft due to its high efficiency. But when less delta-v is required, overall, it can be easily surpassed by smaller liquid fueled engines such as the [[48-7S "Spark" Liquid Fuel Engine|48-7S "Spark"]] engine with a lot better TWR. |
| − | + | It is incredibly difficult to build an ion-rocket which can defeat gravity on [[Kerbin]], because the engine isn't even strong enough to lift itself against gravity, let alone itself and its fuel, a battery and a probe core. But when on a low-gravity moon like [[Minmus]] or [[Gilly]] it is possible to land, start, enter orbit and reach escape velocity with ion-propulsion alone. Since 0.23.5, it is technically possible to create an ion-powered probe, albeit with a minimum of parts, which will be able to defy [[Mun]] gravity. With that in mind, it is also possible to resist gravity with lightweight Ion craft on Duna, Moho, Dres, Eeloo, and every in-game moon with two exceptions: Laythe and Tylo have too high gravity for a single ion thruster, xenon tank, probe core, and battery. | |
| − | + | While it is possible to build an airplane powered solely by this engine, the ion engine's efficiency is awful in the [[atmosphere]]. Unless you are going very far from the KSC, jet planes are much cheaper and more efficient. | |
| − | + | Ion-powered "ferries" may also be useful for moving fuel, oxidizer and/or kerbonauts between two larger vessels, by keeping the large craft at such range that only one of them is within draw distance from the "ferry" at any moment, performance loss can be avoided. It is generally more fuel-efficient to move fuel and oxidizer between two ships using a ferry than it would be to dock the larger craft together using their own engines and RCS. | |
| − | + | Because it uses only about 0.485 units of xenon per second, one [[PB-X50R Xenon Container]] with 400 units of xenon can supply the engine for almost 14 minutes. The other larger tank [[PB-X150 Xenon Container]] with 700 units of xenon has enough to supply the engine more than 24 minutes. | |
| − | |||
| − | == | + | === Electrical vs Xenon consumption === |
| + | While the consumption ratios listed in the part.cfg files are normally relative mass flows (1.8 electricity and 0.1 xenon here), this breaks down somewhat with massless resources like electricity. Rather, the entire mass flow goes to the xenon, with the relative ratio (1.8 to 0.1, or 18 in total) creating a seemingly disproportionate drain. | ||
| + | |||
| + | Calculating the mass and unit flow from specific impulse and thrust: | ||
| + | <math>I_{sp} = \frac{F}{\dot m \cdot g_0} \Rightarrow \frac{F}{I_{sp} \cdot g_0} = \dot m \Rightarrow \frac{2000 N}{4200 s \cdot 9.80665 \frac{m}{s}} = 0.04856 \frac{kg}{s}</math> | ||
| + | <math>Xe flow = \frac{\dot m}{\rho} = \frac{0.04856\frac{kg}{s}}{0.1\frac{kg}{l}} = 0.4856\frac{l}{s}</math> | ||
| + | <math>Electricity flow = Xe * ratio = 0.4856 * 18 = 8.740 zaps/s</math> | ||
| + | |||
| + | == Product description == | ||
{{Quote | {{Quote | ||
| − | |By emitting ionized xenon gas through a small thruster port, the PB-ION can produce incredibly efficient propulsion, but with a downside of very low thrust and high expense. The general perception of this engine as being powered by "witchcraft" has unfortunately given it a sour reputation. | + | |By emitting ionized xenon gas through a small thruster port, Dawn can produce incredibly efficient propulsion, but with a downside of very low thrust and high energy usage. According to ISP Electronics sales reps, the rumours of this engine being powered by "dark magic" are largely exaggerated.|manufacturer=ISPE |
| − | |Ionic Protonic Electronics}} | + | }} |
| + | |||
| + | {{Quote|By emitting ionized xenon gas through a small thruster port, the PB-ION can produce incredibly efficient propulsion, but with a downside of very low thrust and high expense. The general perception of this engine as being powered by "witchcraft" has unfortunately given it a sour reputation.|Ionic Protonic Electronics (0.18-0.23)}} | ||
| + | |||
| + | == Trivia == | ||
| + | |||
| + | Although the 2 kN IX-6315 "Dawn" Electric Propulsion System is considered to have very low thrust in KSP, real-life Hall effect thrusters typically have orders of magnitude less thrust usually below 1 N (0.001 kN). They make up for this by having a service life of thousands of hours of continuous operation and consuming fuel extremely slowly, which would have been impractical in the game. | ||
| + | |||
| + | The name "Dawn" is a reference to NASA's [[w:Dawn_(spacecraft)|''Dawn'' spacecraft]], which is NASA's first interplanetary space probe to use an ion engine for propulsion. | ||
== Gallery == | == Gallery == | ||
<gallery> | <gallery> | ||
| − | + | Solar ion engine plane.png | A Solar Glider Ready for take-off. This ship uses ion engines. | |
| − | + | Solar ion engine plane flying.png | The Solar glider in action. | |
| − | IPSP orbit.png | The [[Ion-Powered Space Probe]] stock craft an ion engine. | + | IPSP orbit.png | The [[Ion-Powered Space Probe]] stock craft, powered by an ion engine. |
</gallery> | </gallery> | ||
== Changes == | == Changes == | ||
| − | ; | + | ;[[1.0]] |
| + | *Moved from Utility to Engines | ||
| + | ;[[0.25]] | ||
| + | * Moved to Propulsion from Utility. | ||
| + | ;[[0.23.5]] | ||
| + | * Ionic Protonic Electronics renamed Ionic Symphonic Protonic Electronics, description changed, thrust increased from 0.5 to 2, relative electricity reduced from 12 to 1.8, description changed. | ||
| + | ;[[0.18]] | ||
* Initial Release | * Initial Release | ||
Latest revision as of 07:44, 19 January 2021
| IX-6315 "Dawn" Electric Propulsion System | ||
 | ||
| Ion engine by Ionic Symphonic Protonic Electronics | ||
| Radial size | Tiny | |
| Cost | (total) | 8 000.00 
|
| Mass | (total) | 0.250 t |
| Drag | 0.2 | |
| Max. Temp. | 2000 K | |
| Impact Tolerance | 7 m/s | |
| Research |  Ion Propulsion
| |
| Unlock cost | 16 800
| |
| Since version | 0.18 | |
| Part configuration | ionEngine.cfg | |
| Maximum thrust | (1 atm) | 0.05 kN |
| (vacuum) | 2.00 kN | |
| Isp | (1 atm) | 100 s |
| (vacuum) | 4200 s | |
| Fuel consumption | 0.486  /s
| |
| Electricity required | 8.74 ⚡/s | |
| Testing Environments | ||
| On the surface | No | |
| In the ocean | No | |
| On the launchpad | No | |
| In the atmosphere | No | |
| Sub-orbital | Yes | |
| In an orbit | Yes | |
| On an escape | Yes | |
| Docked | No | |
| Test by staging | Yes | |
| Manually testable | Yes | |
| Packed volume | 160 l | |
The IX-6315 "Dawn" Electric Propulsion System is a tiny-sized engine which runs on electricity and xenon gas propellant. It's modeled after the real-world Hall effect thruster.
Contents
Usage
This engine has a phenomenal fuel efficiency (4200 s Isp), but very low thrust and requires a substantial amount of electricity to operate. Xenon gas is provided by xenon containers like the PB-X50R Xenon Container, PB-X150 Xenon Container or PB-X750 Xenon Container. Electricity can be obtained using solar panels, radioisotope batteries (RTGs), and fuel cells. Solar panels are recommended in this case, however RTGs are very efficient when traveling to far distances such as Jool and Eeloo. The amount of electricity needed to keep one ion engine running at full thrust is roughly equivalent to half the output of one Gigantor XL Solar Array (however one array will power two engines only near peak sun exposure around Kerbin), 6 Fuel Cells, 12 PB-NUK Radioisotope Thermoelectric Generators, or 25 OX-STAT Photovoltaic Panels at peak output. When pairing with solar panels, it is highly recommended to bring more than it needs (slightly less than 9 Ec/s). Not all panels are at peak output during operations, and maximum available power falls of with the square of the distance from the star.
Batteries can be used to store the electricity since there may be times the solar panels will be blocked from the Sun by objects or the dark side of celestial bodies. For extended burns in the darkness the fuel cells happen to be a good choice. When the power is provided by the fuel cells the majority of the mass flow (about 69.2%) is liquid fuel and oxidizer used by the fuel cell. Thus the ion engine powered by the fuel cell may be seen as having much more modest but still impressive effective Isp of 1293 sec. However if the burn doesn't take more than a couple of hours the stack of RTGs providing the same amount of power (and thus thrust) tend to be heavier than the fuel cell array and its fuel tank. The RTGs should be reserved for very long low-thrust burns in the deep space.
The ion engine is good for fine tuning of orbits. It was also a popular propulsion method for planes on planets on which jet engines don't work, though its current thrust falloff reduces the value there. Due to its great fuel efficiency it is also well-suited for interplanetary travel, but maneuvers tend to take a long time to complete due to its very low thrust-to-weight ratio -- it is advised to use it for very small craft, and to use physics-warp while propelling with it. Usually the engine is used on long range craft due to its high efficiency. But when less delta-v is required, overall, it can be easily surpassed by smaller liquid fueled engines such as the 48-7S "Spark" engine with a lot better TWR.
It is incredibly difficult to build an ion-rocket which can defeat gravity on Kerbin, because the engine isn't even strong enough to lift itself against gravity, let alone itself and its fuel, a battery and a probe core. But when on a low-gravity moon like Minmus or Gilly it is possible to land, start, enter orbit and reach escape velocity with ion-propulsion alone. Since 0.23.5, it is technically possible to create an ion-powered probe, albeit with a minimum of parts, which will be able to defy Mun gravity. With that in mind, it is also possible to resist gravity with lightweight Ion craft on Duna, Moho, Dres, Eeloo, and every in-game moon with two exceptions: Laythe and Tylo have too high gravity for a single ion thruster, xenon tank, probe core, and battery.
While it is possible to build an airplane powered solely by this engine, the ion engine's efficiency is awful in the atmosphere. Unless you are going very far from the KSC, jet planes are much cheaper and more efficient.
Ion-powered "ferries" may also be useful for moving fuel, oxidizer and/or kerbonauts between two larger vessels, by keeping the large craft at such range that only one of them is within draw distance from the "ferry" at any moment, performance loss can be avoided. It is generally more fuel-efficient to move fuel and oxidizer between two ships using a ferry than it would be to dock the larger craft together using their own engines and RCS.
Because it uses only about 0.485 units of xenon per second, one PB-X50R Xenon Container with 400 units of xenon can supply the engine for almost 14 minutes. The other larger tank PB-X150 Xenon Container with 700 units of xenon has enough to supply the engine more than 24 minutes.
Electrical vs Xenon consumption
While the consumption ratios listed in the part.cfg files are normally relative mass flows (1.8 electricity and 0.1 xenon here), this breaks down somewhat with massless resources like electricity. Rather, the entire mass flow goes to the xenon, with the relative ratio (1.8 to 0.1, or 18 in total) creating a seemingly disproportionate drain.
Calculating the mass and unit flow from specific impulse and thrust:
Product description
| “ | By emitting ionized xenon gas through a small thruster port, Dawn can produce incredibly efficient propulsion, but with a downside of very low thrust and high energy usage. According to ISP Electronics sales reps, the rumours of this engine being powered by "dark magic" are largely exaggerated. — Ionic Symphonic Protonic Electronics |
” |
| “ | By emitting ionized xenon gas through a small thruster port, the PB-ION can produce incredibly efficient propulsion, but with a downside of very low thrust and high expense. The general perception of this engine as being powered by "witchcraft" has unfortunately given it a sour reputation. — Ionic Protonic Electronics (0.18-0.23) |
” |
Trivia
Although the 2 kN IX-6315 "Dawn" Electric Propulsion System is considered to have very low thrust in KSP, real-life Hall effect thrusters typically have orders of magnitude less thrust usually below 1 N (0.001 kN). They make up for this by having a service life of thousands of hours of continuous operation and consuming fuel extremely slowly, which would have been impractical in the game.
The name "Dawn" is a reference to NASA's Dawn spacecraft, which is NASA's first interplanetary space probe to use an ion engine for propulsion.
Gallery
A Solar Glider Ready for take-off. This ship uses ion engines.
The Solar glider in action.
The Ion-Powered Space Probe stock craft, powered by an ion engine.
Changes
- Moved from Utility to Engines
- Moved to Propulsion from Utility.
- Ionic Protonic Electronics renamed Ionic Symphonic Protonic Electronics, description changed, thrust increased from 0.5 to 2, relative electricity reduced from 12 to 1.8, description changed.
- Initial Release
