PB-ION Electric Propulsion System
|PB-ION Electric Propulsion System|
| Ion engine by |
Ionic Protonic Electronics
|Max. Temp.||3600 K|
|Impact Tolerance||7 m/s|
|Maximum thrust||0.5 kN|
|Fuel consumption||0.121 x/s|
|Thrust vectoring||× No|
|Electricity required||14.548 E/s|
The PB-ION 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. Although it is a propulsion system, it can be found in the utility tab of the VAB and SPH.
This engine has a phenomenal fuel efficiency (4200 s Isp), but very low thrust and requires an immense amount of electricity to operate. Xenon gas is provided by xenon containers like the PB-X150 Xenon Container. Electricity can be obtained using solar panels and radioisotope batteries. The amount of electricity needed to keep one ion engine running at full thrust is roughly equivalent to the output of one Gigantor XL Solar Array or 20 PB-NUK Radioisotope Thermoelectric Generators.
The ion engine is good for fine tuning of orbits. It is also a popular propulsion method for planes on planets on which jet engines don't work. Due to its great fuel efficiency it is also well-suited for interplanetary travel, but maneuvers take a long time to complete due to its low thrust-to-weight ratio - it is advised to use it for very small craft, and to use physics-warp while propelling with it.
It is practically impossible to build an ion-rocket which can defeat gravity on Kerbin, because the engine isn't even strong enough to lift itself against gravity, yet 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.
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 crafts together using their own engines and RCS.
Because it uses only about 0.121 units of xenon per second, one PB-X50R Xenon Container with 400 units of xenon can supply the engine for more than 55 minutes. The other larger tank PB-X150 Xenon Container with 700 units of xenon has enough to supply the engine more than 96 minutes.
The game lists the electrical consumption as 12 E which is the electricity consumed for 0.1 xenon. To propel 1 xenon a electricity of 120 E is required. With the thrust and specific impulse the calculated fuel flow is 0.0121 kg/s or 0.1214 xenon/s which is more than the listed 0.1 xenon/second. So the electricity consumption is a bit higher at 14.562 E/s. As the Isp given in seconds needs to be multiplied with a slightly higher acceleration than g0 (= 9.81 m/s²) the actual Isp in m/s is higher and therefore the xenon and electrical consumption is lower.
|“|| 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
The Ion-Powered Space Probe stock craft, powered by an ion engine.
- Initial Release