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Ion Engines - Why?


RocketBlam

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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)

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

Yes, in real life they don't car much about burn time as you don't have time warp.

In fact real life lacks lots of unsefull features, however stuff like autosave and reload on death or embarrassing situations is far more requested.

As for the Gigantors they are most used for heavy industrial use like kethane mining where a ton extra weight is less important. for ion craft you use the 1x6 ones.

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The only thing that needs to be added is a way to replenish the xenon inside the tank. And, surprisingly, no one thought of a mod that adds a portable air separation plant into the ship, so you have infinite fuel while inside an atmosphere.

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Sure burn times were a bit of a chore, but I feel it was worth it.

My first Duna flights were with Ion powered probes. Sure feels satisfying in the end; all the more for having to endure the relative hardships along the way in my opinion.

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Without Ion engines I wouldn't have been able to pull of a manned return mission to Moho with BTSM.

Chemical there and Ion back - hour long burns at max time warp but doable without multiple missions for refueling.

If you have the time the insane deltaV is worth exploiting.

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Ions are fantastic for small probes. The burn times are long enough that you often need to adjust on multiple orbits, but it's not too bad. What I've found best is to NOT use the probes straight from Kerbin, since the burn times will just be uncomfortably long (even with the recent improvement to ion thrust). Here's my main probe design:

Y0FRlFC.png

Basically, an LV-N transfer stage carries four small probes (seen at the top) to whichever planet needs them. Once it's passing through the SOI in question, it fires one of the probes, which can then deploy its solar panels and maneuver itself into whatever orbit is needed. The LV-Ns keep the burn times extremely manageable, while still having plenty of efficiency. The probes themselves have a Kethane scanner, mapping scanners, plus the full array of standard sensors and an antenna (which allows them to be used as one-shot atmospheric probes for places like Jool).

But don't discount other uses of ions. My SSTO spaceplane can mount ion pods (xenon plus an engine) on its wingtips; they add ~2 tons to its 32-ton mass, but give it enough raw delta-V to get from Kerbin to Laythe. Sure, the burns take a couple hours, but I can just watch a movie while it goes on its way. The only real headache, fuel storage, can be solved if you download certain mods that add larger xenon tanks (or mod a part for yourself) so that you don't need dozens of tiny tanks to bloat your part count.

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IonSolarSailer.jpg

I use Ion engines a for a ton of things. You can set up orbital stations around planets and use Ion busses to ferry kerbals and equipment between them, you can push around efficient little reusable landers, or leave an Ion drive stage in orbit, buzz down to the surface, load the science onto a lander can and ditch the rest. You can set up a really tight, efficient modular system that way. It forces you to really think about weight differently.

Refueling is an issue. I've been making disposable clusters of xenon canisters with ports on each end, but it would be really, really handy to have larger tanks available.

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I've built this single seat ion craft and I find it pretty awesome - 15k dv and acceleration isn't that bad:

http://imgur.com/a/dgYIA

They definitely have their uses, but mostly for small things like probes/satellites as others have said before me.

What solar panels are you using? I'm looking for some larger ones.

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What solar panels are you using? I'm looking for some larger ones.

Balka wings from Kosmos pack. I use only them and some small LED lights out of the pack so my menus don't get too clustered.

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They're not that bad. I find them incredibly useful for sending light scanner satellites to other bodies. A TWR of 0.20 and a couple thousand m/s of dV do the trick very nicely. It feels like flying a large manned interplanetary ship but handles much better.

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Since .23.5, they are also not bad as lightweight landers...

qpd6lvU.jpg

This one is 2.5t in weight, gets to the Mun from Kerbin orbit but it's efficiency isn't something unbelievably-spectacular, as this one still relies on aerobraking to rendez-vous with the return craft.

And apparently these 2 solar panels are enough to go at full throttle with 4 motors.

...also check out Mesklin's grand-tour craft O _ O

Edited by Overfloater
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I made this probe in an attempt to map the sun... (yes i realize it's pointless cause there's no map information to get from the sun....)

i got it into a 300km by 3mil km polar orbit with 27,000 delta V... it took 5hrs of burn time to complete the whole trip. i was aiming for 300 by 300 but i ran out of fuel. didn't account for the inclination change. this is probably the last time i'll use ion engines for a ship. Its just not that much fun waiting around for the burns.

I've used ion engines to create downforce for driving rovers on moons before but other than that i have no interest in using them anymore.

r2ipGEX.png

also discovered that the small 1x6 solar panels produce 18+ energy per second when you're that close to the sun.

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Oh Cupcake, I do so love your landers, right along with your videos.

I made this lander back before the 23.5 buffing they got. It was my first experience with them and since I had flung my probes far-and-wide throughout the Korbol system. My latest probe (MobIle Kontainer of Interesting Experiements, or M.I.K.I.E. for short) feels absurdly OP compared to those earlier ones XD

I'll probably post video of MIKIE's maiden flight sometime this week once I finish editing the footage.

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So far i use them strictly for my Kethane searching satellites. The small lightweight craft is perfect for such a small and efficient engine. Adjusting the orbit is a piece of cake.

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Oh Cupcake, I do so love your landers, right along with your videos.

I made this lander back before the 23.5 buffing they got. It was my first experience with them and since I had flung my probes far-and-wide throughout the Korbol system. My latest probe (MobIle Kontainer of Interesting Experiements, or M.I.K.I.E. for short) feels absurdly OP compared to those earlier ones XD

I'll probably post video of MIKIE's maiden flight sometime this week once I finish editing the footage.

Great video! Loved the soundtrack too, well done! :wink:

Cupcake...

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