Ion engines

[Rakaydos]

I'm working on an ion powered kethane lifter for minmus and gilly. 24 ion engines, with just enough solar power to full throttle directly into the sun.

[Sabreur]

I don't know how you feel about mods, but this is one area where mechjeb is damn near essential. The ability to set a maneuver node and just let the autopilot handle things while you go grab a sandwich or something is critical to using ion engines without losing your mind.

I've used ion engines in two places - one for a Moho probe, and a big cluster of them for a high-efficiency ferry that would take fuel from my orbital fuel depo to whatever vessel needed it. Even then I ended up replacing the fuel ferry with a nuclear-engine version. Not quite as efficient, but much easier on my sanity.

[WhiteWeasel]

People apparently don't pys-warp with ion probes. A 12 minute burn can be cut down to mere 3 minutes. Usually for any probe under 4 tons and ferrying in between moons. Probably my 3rd favorite engine.

[DerpenWolf]

I got Bill to Duna with a Mk1 capsule and a pair of ion engines relatively easily (Mostly by an accidental munar assist), so far I have noticed that to use ion engines effectively (meaning you don't wait for a hour long burn) you have to use get gravity assists and use aerobraking as much as you can (getting a low perigee for an encounter helps). Just keep your craft light and if you are impatient use a small rocket stage to assist your exit of kerbin's sphere of influence.

[WafflesToo]

Ahhhhhhhhh! AUGHHHHHHHHHHHHH! Stop using Gigantors to power ion probes! Their PWR is TERRIBLE!

*cough*

Anyway, I use them for small interplanetary missions like most. Physical time acceleration helps immensely with the burn times on these. I do have plans on paper for a 3-Kerman "solar sailer" but I haven't tried building one yet.

[Streetwind]

Ahhhhhhhhh! AUGHHHHHHHHHHHHH! Stop using Gigantors to power ion probes! Their PWR is TERRIBLE!

Educate us, then, as to how we best provide the 15 charge/sec that each ion engine requires?

[Brapness]

I'll admit to only using them for the first time recently, but I actually quite like them. In career mode I used ion probes as a test cargo for my shuttle program and as such had two in orbit. They're off to Dres and Eeloo now. Even with time warp those are very long burns, but I usually have the tv on in the background when I play KSP so I just watch that.

It's possible when money is introduced that ion probes might allow distant travel quite a bit cheaper than conventional rockets, which require much larger lifters to get them into orbit.

[Superfluous J]

Educate us, then, as to how we best provide the 15 charge/sec that each ion engine requires?

Short answer: OX-STATs if you can guarantee they'll always be aimed at the sun with as little supporting structure as possible. Better is OX-4Ws, as they track the sun and don't need much if any added structure. Don't use Gigantors, they're the worst solar panel. and never, ever use PB-NUKs. They're horrible from a mass/energy standpoint.

Long answer:

[table][tr][td]

Thing

[/td][td]

OX-STAT

[/td][td]

OX-4W

[/td][td]

SP-L

[/td][td]

Gigantor

[/td][td]

PB-NUK

[/td][/tr]

[tr][td]

tons

[/td][td]

0.0050

[/td][td]

0.0175

[/td][td]

0.0250

[/td][td]

0.3500

[/td][td]

0.0800

[/td][/tr]

[tr][td]

e/s

[/td][td]

0.7500

[/td][td]

2.0000

[/td][td]

2.0000

[/td][td]

18.0000

[/td][td]

0.7500

[/td][/tr]

[tr][td]

e/s/ton

[/td][td]

150.0000

[/td][td]

114.2857

[/td][td]

80.0000

[/td][td]

51.4286

[/td][td]

9.3750

[/td][/tr]

[tr][td]

#/ion

[/td][td]

19.3973

[/td][td]

7.2740

[/td][td]

7.2740

[/td][td]

0.8082

[/td][td]

19.3973

[/td][/tr]

[tr][td]

tons/ion

[/td][td]

0.0970

[/td][td]

0.1273

[/td][td]

0.1819

[/td][td]

0.2829

[/td][td]

1.5518

[/td][/tr][/table]

Edited January 31, 2014 by 5thHorseman
made the table a little more succinct and readable

[magnemoe]

I like the long six pannels ones, one benefit is that they don't cast shadow on each other. Downside with static is that you need extra ones to be sure to face the sun.

Yes you can rotate but not change if you have the sun in front or behind you.

Solar rider took me from Eve to Moho landing and back, the lander is in front, option to drop outer part then dry and get even more Dv for less trust.

[Pineapple Frenzy]

After adding ANY structural element to an OX-Stat, they no longer hold a mass/energy advantage over the 1x6 panels. My strategy has been this:

The PX-Stat panels are simply a redundancy in case I forget to open my other panels right away.

I use this vessel to cruise around the moons of Jool. I'll get them there by conventional rocket. Once captured in Jool's SOI, I'll switch to the ion vessel and sail around for a few hours. It's fun.

[Streetwind]

Hah, I've always had a feeling that the static panels were overpwoered...

[WafflesToo]

Educate us, then, as to how we best provide the 15 charge/sec that each ion engine requires?

Looks like I got ninja'd a few times over XD. But yes, the OX-4 really is the way to go. I usually build a spine out of octostruts and install them in a line along the dorsal and ventral sides, reminds me of a fore-and-aft rigged sailing ship.

[Pineapple Frenzy]

That's how I started building my solar cruisers. They were very elegant. The only problem I found occurred when making orbit adjustments at low altitude. I found the solar panels would block each other if the edge of the array's plane pointed at the sun. Unfortunately, in the sailing ship configuration the axis of the ion engine was parallel to the array plane to. So if the vessel was pointed prograde or retrograde to the sun, as it must be when burning at terminus so as to be in sunlight at both sides of a low inclination orbit, then I often did not have energy to make the burn. I solved this by making the engine axis perpendicular to the array axis (as above). Not as visually pleasing as the sailing ship, but certainly more versatile for low inclination orbiting. But this configuration is much harder to load on to a launch vehicle.

[WafflesToo]

That's how I started building my solar cruisers. They were very elegant. The only problem I found occurred when making orbit adjustments at low altitude. I found the solar panels would block each other if the edge of the array's plane pointed at the sun. Unfortunately, in the sailing ship configuration the axis of the ion engine was parallel to the array plane to. So if the vessel was pointed prograde or retrograde to the sun, as it must be when burning at terminus so as to be in sunlight at both sides of a low inclination orbit, then I often did not have energy to make the burn. I solved this by making the engine axis perpendicular to the array axis (as above). Not as visually pleasing as the sailing ship, but certainly more versatile for low inclination orbiting. But this configuration is much harder to load on to a launch vehicle.

I think they changed the occlusion mechanics in one of the updates. The long-thin OX4s have to be almost perfectly inline with each other to block out the sun now. The few times I've had trouble I just angle the burn off a few degrees for the first half of the burn them a few in the other for the second half.

[problemecium]

I almost exclusively use OX-STATs. Not so much because they're OP, but with 0.23's science mechanics there's little need for me to have a lot of big panels to power transmitters. And I also don't use ion engines. They're just not superior enough to good ol' nuclear engines... or even 48-77s for that matter.

[WafflesToo]

I almost exclusively use OX-STATs. Not so much because they're OP, but with 0.23's science mechanics there's little need for me to have a lot of big panels to power transmitters. And I also don't use ion engines. They're just not superior enough to good ol' nuclear engines... or even 48-77s for that matter.

I can build a well equipped duna science probe using ion engines that masses less than just the nuke engine by itself :-p

[Aragosnat]

Short answer: OX-STATs if you can guarantee they'll always be aimed at the sun with as little supporting structure as possible. Better is OX-4Ws, as they track the sun and don't need much if any added structure. Don't use Gigantors, they're the worst solar panel. and never, ever use PB-NUKs. They're horrible from a mass/energy standpoint.

Long answer:

[table][tr][td]

Thing

[/td][td]

OX-STAT

[/td][td]

OX-4W

[/td][td]

SP-L

[/td][td]

Gigantor

[/td][td]

PB-NUK

[/td][/tr]

[tr][td]

tons

[/td][td]

0.0050

[/td][td]

0.0175

[/td][td]

0.0250

[/td][td]

0.3500

[/td][td]

0.0800

[/td][/tr]

[tr][td]

e/s

[/td][td]

0.7500

[/td][td]

2.0000

[/td][td]

2.0000

[/td][td]

18.0000

[/td][td]

0.7500

[/td][/tr]

[tr][td]

e/s/ton

[/td][td]

150.0000

[/td][td]

114.2857

[/td][td]

80.0000

[/td][td]

51.4286

[/td][td]

9.3750

[/td][/tr]

[tr][td]

#/ion

[/td][td]

19.3973

[/td][td]

7.2740

[/td][td]

7.2740

[/td][td]

0.8082

[/td][td]

19.3973

[/td][/tr]

[tr][td]

tons/ion

[/td][td]

0.0970

[/td][td]

0.1273

[/td][td]

0.1819

[/td][td]

0.2829

[/td][td]

1.5518

[/td][/tr][/table]

I do agree with you that the OX-STATs are great. Just one tiny tiny little problem thou. Around Kerbin you will need 20 of the buggers on just one side to have full power non-stop. Bit hard to fit all on just 1 xenon can, 1 small round battery, Ion drive and a probe core. Do agree when used they are best for going to Moho with as one panel if I remember right can get 20+ per second. But, the real problem is when you start moving away. For around Jool. You would need 40 of them as 2 Gigantor was what was needed for around there. And around Eeloo it was around 3 Gigantor for full power. The reason is because of the square the distince law that the light and the game uses. Eventually one could be better off with 20 PB-Nuk as either the part count and or mass needed will be greater then the number of PB-Nuks.

[Superfluous J]

I do agree with you that the OX-STATs are great. Just one tiny tiny little problem thou. Around Kerbin you will need 20 of the buggers on just one side to have full power non-stop.

Which is why I said "Better is OX-4Ws" (though as others have said, the OX-4Ls have less problems with shadows).

[Aragosnat]

Which is why I said "Better is OX-4Ws" (though as others have said, the OX-4Ls have less problems with shadows).

I know others and you did. Just wanted to point it out to others who might have missed the amount needed, also would be intresting to see the cost to ton ratio as well as the energy gain for all the planets.

Either way. An excesive amount of extra parts needed regardless of OX and SP (at least by my standards) to run at full power. But, if you are trying to keep the part cound down as well as have full power, Gigantor is the way to go. And PB-Nuk will be good for when a modder finds a nice way to add in other star systems or need to burn in the shadow of a planet or moon. Better to have some way to change course then none at all.

Edited January 31, 2014 by Aragosnat

[Ozzallos]

I got a little overly ambitious...

TwerkStar III will drain a 12k battery inside a minute, and that's with panels deployed backed by 8 blutonium rods.

Good news is recharge is relatively fast (3 minutes), and 1/3 is the break even point on the throttle.

Maybe I'll use some of the tricks I see here for TwerkStar IV to reduce mass, since acceleration is still breathtakingly lethargic.

[Aragosnat]

@Ozzallos:

Well goodnews then. It seems like the next update the IonDs will get a boost. Also if you ditched the nose cone. You will get a better Delta-V and shorter Burns. Less mass = more speed and more fuel.

[problemecium]

What I'd really like to see is a patch / mod that lets you turn on an ion engine and then timewarp / switch vessels. You'd of course have to manage your timing and make sure to go back and turn it off at the right time so as not to overshoot.

[magnemoe]

I know others and you did. Just wanted to point it out to others who might have missed the amount needed, also would be intresting to see the cost to ton ratio as well as the energy gain for all the planets.

Either way. An excesive amount of extra parts needed regardless of OX and SP (at least by my standards) to run at full power. But, if you are trying to keep the part cound down as well as have full power, Gigantor is the way to go. And PB-Nuk will be good for when a modder finds a nice way to add in other star systems or need to burn in the shadow of a planet or moon. Better to have some way to change course then none at all.

Gigantor is for heavy industrial use kethane or ore mining and processing, here the weight is not very important as you use ships of 50 ton or more.

[Ozzallos]

@Ozzallos:

Well goodnews then. It seems like the next update the IonDs will get a boost. Also if you ditched the nose cone. You will get a better Delta-V and shorter Burns. Less mass = more speed and more fuel.

I was willing to make performace sacrifices for aesthetics

[WhiteWeasel]

@Ozzallos:

Well goodnews then. It seems like the next update the IonDs will get a boost. Also if you ditched the nose cone. You will get a better Delta-V and shorter Burns. Less mass = more speed and more fuel.

Sweet! Do you have the source? Better Ion engines would be awesome!