Ion Engines - Why?

[RocketBlam]

It seems to me that Ion engines would only be useful for very long flights - like, outside the solar system, taking years. I'm not sure when they would be useful for traveling even to the most remote planet. Please edumacate me.

[Joshington]

I personally use them for completing and perfecting orbits for my satellites. I wouldn't have made it to Moho that little thing.

[Greenspan]

Link to Edumacation

[Ravenchant]

They are useful (if you are patient), mostly for probes weighing only a ton or two. Burns can take more than an hour without time acceleration, yes, but the upside is insane delta-v. Even a tiny probe can get anywhere in the system using them - except perhaps Moho.

[Tank Buddy]

The only bodies they are practical to land on are Gilly, Bop, Pol, and Minmus. The last 3 are pushing the limits on "Practical". I have a successful base on Gilly, and because of the insane Isp, I'll never be able to use all of the xenon. Since escape velocity is 35 m/s and the fastest safe, circular orbit never exceeds 20 m/s, it is very manageable, except it takes longer than I would like because of the low speeds and restricted time warp.

For me, I would never try to use them for interplanetary, especially not pushing payloads.

[dangerbird2]

As Joshington says, they are good for fine orbit adjustments. It's also ideal for making an orbital insertion to Moho, which has ample sunlight to power the engine for a very ÃŽâ€v intensive burn. And don't quote me on this, but I believe that the newest version of Interstellar mod allows burning its ion engines while running on-rails timewarp

[Captain Sierra]

It seems to me that Ion engines would only be useful for very long flights - like, outside the solar system, taking years. I'm not sure when they would be useful for traveling even to the most remote planet. Please edumacate me.

Ion engines in the stock game are very weak, but outrageously overpowered by real life standards. Now, one fix is to speed up time beyond just 4x phys warp, and this was doable with the old DynamicWarp mod (the reincarnation, Time Control, states that it may blow up crafts. This should be read as ]always as I have yet to make a ship it won't explode, and it only slows, no acceleration). The trick is build very light. Two gigantors will power one ion engine ANYWHERE in the kerbal system.

Ion engines can enable a probe to flyby every planet without refueling. They have insanely high delta V because of insane Isp. Ion engines should not be used for quick burns or for payload, it simply won't work.

If you simply want moar power, go get Near Future Propulsion, which adds a ton more ionic engines, which have higher thrusts, and you also get more ways to power those greedy engines.

[magnemoe]

Solar rider says hi, this was used for going from Eve to Moho during my 100 ton from LKO grand tour. No it does not have an great focus on crew facilities, however it had better twr than the LV-N ship who took him to Eve.

It also has serious dV 10Km/s is with the Moho lander in front, in an emergency you can pump all xenon to the two central tanks drop the outer tanks and engines and have 4Km/s left.

Yes it would be no issue going to Jool from Moho with it.

Edit, yes that is after landing on Moho.

On the other hand the colonization class factory ship burning for Jool has better crew facilities. However as you see everybody is happy and that is the important part.

[PPR]

The thing to remember about ion engines is that they give you range and precision. So if you are trying to fine tune your intercept with a far away planet or land a probe on a low-g moon like Gilly they can be useful. They don't have the thrust to establish an orbit, but if you are in orbit they give you plenty of range to maneuver. Think of them as a niche engine. There are tasks that an ion engine just will not do, but they do have some uses.

[James_Eh]

As Joshington says, they are good for fine orbit adjustments. It's also ideal for making an orbital insertion to Moho, which has ample sunlight to power the engine for a very ÃŽâ€v intensive burn. And don't quote me on this, but I believe that the newest version of Interstellar mod allows burning its ion engines while running on-rails timewarp

Wow, I must be doing something wrong in my trips to Moho. Not disputing the dV part, but rather the time-while-you-are-encountering Moho part i.e. unless I had 40+ ion engines "blazing" from the moment of encounter, I would blow right through to the escape. I guess you could start the burn way before SOI change?

[RSwordsman]

Why ion engines? Because you've got electricity to burn and a blue glow looks way more high tech than gratuitous flames.

[Rakaydos]

Insired by a random comment, I just built an ion-powered glider. It's currently over 12 KM from the runway at 12m/s, and climbing at 45 milimeters per second.

[Rodyle]

I am kind of warming up towards ion engines. As long as you make INCREDIBLY light crafts, the acceleration is not much lower than what you'd get out of a large nuclear-powered ship (read: in the neighbourhood of 1m/s^2). The other day I sent 4 probes into interplanetary space, waiting for their nodes to get an intercept with other objects. Yes, it's not the most interesting job, but the burn shouldn't take more than 30 minutes in-game time, so 7.5 minutes for me with time acceleration. I played some other games in the mean time and watched a few videos on youtube.

[Streetwind]

It seems to me that Ion engines would only be useful for very long flights - like, outside the solar system, taking years. I'm not sure when they would be useful for traveling even to the most remote planet. Please edumacate me.

Why make a new thread about this, when this thread is literally six lines below it...?

[SargeRho]

What you are doing by doing the orbital capture burn is basically matching your orbital velocity around the sun with that of Moho, So one way to reduce the time it takes to enter orbit, is to get close to Moho's orbit before the encounter, sort of spiraling inwards.

You also want to make use of gravity slingshots, lots of gravity slingshots. On the one occasion where I went to Moho, I used a slingshot maneuver around Moho itself to get closer to its orbit, and then only had to do a rather short burn to get into orbit.

Edited February 19, 2014 by SargeRho

[magnemoe]

Wow, I must be doing something wrong in my trips to Moho. Not disputing the dV part, but rather the time-while-you-are-encountering Moho part i.e. unless I had 40+ ion engines "blazing" from the moment of encounter, I would blow right through to the escape. I guess you could start the burn way before SOI change?

The issue with ion engines is that you want to keep you payload down. In short you don't want to carry more than probe and light science instruments, perhaps kethane scanner. Solar rider it pretty lightweight, it did not even have an seat on the lander as it weight 50 kg, i would not make any ion crafts so heavy again.

Keep payload below 100 kg and you do nice.

[ZodiaK]

because this:

Javascript is disabled. View full album

[eldorim]

They are useful (if you are patient), mostly for probes weighing only a ton or two. Burns can take more than an hour without time acceleration, yes, but the upside is insane delta-v. Even a tiny probe can get anywhere in the system using them - except perhaps Moho.

And they take much cpu power.. the game gets very slow, when i activate them

[eldorim]

They are useful (if you are patient), mostly for probes weighing only a ton or two. Burns can take more than an hour without time acceleration, yes, but the upside is insane delta-v. Even a tiny probe can get anywhere in the system using them - except perhaps Moho.

And they slow the game massively down.. 1 second are now 6 seconds in realtime, when i activate them...

[Russoft]

I can't remember which, I think Bop. I made a perfect landing using an Ion engine. Granted, it was a small probe and I monitored my velocity carefully, but I had enough thrust that I could take have taken off again if I didn't topple over upon landing due to a lack of landing legs. On all other planets, Ion engines failed me spectacularly.

[Caelib]

MOD ALERT: Necro thread! This argument doesn't even seem valid anymore given the changes in the ARM patch.

[timsfitz]

I have an ion only spaceplane that can fly to Duna, land, then easily fly back to kerbin no problem. It's not even that slow with time acceleration.

Next I'm trying a SSTL(aythe), which should be fairly easy.

[NERVAfan]

Part of the "problem" with ions is that KSP delta-V requirements are scaled down from the real world, and LV-Ns are available in KSP. So you don't "need" ions to go anywhere in the system.

Ions are useful in real life despite their thrust being more than four orders of magnitude worse than the KSP ones because:

- we don't have nuclear rockets, so the next best Isp available is chemical rockets

- delta V requirements are much higher

- launcher size is much more limited than in KSP so you can't just bring 200 tons of fuel

-you can burn constantly through the mission so low thrust is less important (you can't really do this in KSP without mods)

The trick is build very light. Two gigantors will power one ion engine ANYWHERE in the kerbal system.

Gigantors are much less efficient in terms of power per mass than the smaller folding panels, IIRC.

[Soda Popinski]

I haven't installed Interstellar yet (next "campaign mode" game). Watching Scott Manley's GDC interview with Squad, he mentioned the Interstellar ion drives function while in non-physics time warp. I'd hope this gets into stock KSP ion engines, so they can be used in a more realistic manner. Ion engines are typically fired for months at a time.

[merendel]

I haven't installed Interstellar yet (next "campaign mode" game). Watching Scott Manley's GDC interview with Squad, he mentioned the Interstellar ion drives function while in non-physics time warp. I'd hope this gets into stock KSP ion engines, so they can be used in a more realistic manner. Ion engines are typically fired for months at a time.

I cant remember if manly had that wrong or you just misquoted but no KSPI does not have an ION type drive that works in non physics warp. KSPI equivelent to ion would be the plasma thrusters, an electric powered drive with more fuel options but similar principle. They still cant be used in timewarp because the game is hardcoded to block TW while throttled up.

What works in non phisics warp is the solar sail which is not a traditional drive. You cant actualy throttle up or down with the solar sail, instead what happens is the mod simply updates the orbit based on the relitive position to kerbol constantly even during timewarp. This bypasses the hardcoded limit in the game that blocks TW while throttled up.