Jump to content

Ion drive efficiency--how have you used them?


birrhan

Recommended Posts

I occasionally use them on interplanetary probes. Generally only as a final stage when I plan on relocating the probe's orbit. Its good for mapping a body by changing orbital inclination as well as switching between different moons of Jool or the moons of other planets. I tend to go more for boots on the ground missions these days though.

Link to comment
Share on other sites

I tried launching an ion probe to Moho, while it was burning, i went to the toilet and did lots of things. By the time i checked back on it, it was 1/3 done (after about an hour). After that i declared the ion drive useless, except for looking awesomeily sci-fi.

The burn was estimated to 3 hours by the manouver planner in game....

Link to comment
Share on other sites

I love the ion engine for more precise positioning of satellites, and I occasionally do ion powered missions just for the fun of it, but MechJeb babysits while I do something else in that case.

My kethane probe currently mapping kerbin. It's 2 tonnes with 1 ion engine, after getting it back from the Mun on Ion power alone it'll be my last.

Yeah, a 0.02 TWR would be excruciating, especially without MechJeb, though I did a trip to Jool and back with a 0.12 TWR. Between the low TWR and the fact the ship had so many parts that the physics engine couldn't run in real time, 45 minute burns were pretty common for that mission.

Link to comment
Share on other sites

  • 3 weeks later...

When I was new to KSP, I wanted to build a space station. Simple enough, right? Get a core up there, and dock stuff to it.

My first addon module however only had one docking port aside from its inline that I intended for use with shuttles to dock to station with, and the port was used by the rocket to get it into LKO. In order to dock the thing, I would have to stage-separate the module from the rocket, which created an obvious problem. My solution? Twin Ion Engines, well actually Quad since it was two prograde and two retrograde, but you get the idea. I radially attached ion engines and used them to adjust the orbits to rendezvous, approach, and dock. At the time, I was unaware of ijklhn RCS translation keys; I don't remember if they didn't cover those in the tutorial or if they did but I forgot. Either way, I had RCS used only for wasdqe rotational controls and the pro/retro ions for translating the module to perform all the necessary orbital manuevers.

I got it attached, but it was not a method I wanted to repeat. To avoid any accidents, I used decouplers to remove the engines after I was done with the docking, though I put the decouplers on backwards so they stuck behind. Ah well, they add a bit of detail to the thing.

Other than that insanity, probes. And a rover as well because why not, and ion was more useful on rover for survivable high speed than a jet. Also, a tank, as the main "laser cannon" on the not-really-a-turret, because I can.

Link to comment
Share on other sites

I had a fairly large science probe with 4 ion engines launched from Kerbin and then used the engines to circularise my orbit and then get out to the mun.

I think i could use them to take me out much further.

The payload weight im not sure on, but its the mapsat mapper + the Kethane heavy mapper and 2 communication aerials, some lights and the largest probe body (and the quad adapter and 4x ion engine+xenon fuel tank).

Link to comment
Share on other sites

Polar mapping satellites. Since plane changes can be ridiculously expsive as far as Delta-V is concerned, a tiny satellite with a super effecient engine can start in any orientation and eventually end up in a polar orbit.

I don't actually use the mapping mod, but I do "role-play" one from time to time. I built a craft that can launch 4 satellites/probes at once. So I've used the ion engines combined with RTG for power to move the 4 probes from my launch craft into the different orbital planes.

Link to comment
Share on other sites

I mostly use ions for precise orbital adjustments, normally only on geosynchronous flights where precision is key.

I've done that too. I also used a pair on each of my station cores on my old refueling station (which never refueled anything, ironically) for the same purpose. It's the one case where their weakness is an advantage: A throttled-down Ion is less powerful than RCS, so you can execute fine orbital adjustments really, really well. To a precision greater than the physics system itself can handle, actually.

Link to comment
Share on other sites

I used them to get into orbit around Tylo, Bop, Vall and Pol before I was capable of making a rocket capable of enough dV to get to Jool and do anything more than aerobrake at Laythe and land there. After 6-7 hours of ion burns I can safely say I'll never do that ever again.

Besides, I have a rocket capable of 10km/s dV from LKO now :D

Link to comment
Share on other sites

I use an ion engine on every probe I launch. They're great for orbit adjustments, plus the ton of dV allows for lots of orbital changes. The only problem I have with them is the power draw when they're running.

I haven't used them on anything bigger.

Link to comment
Share on other sites

One word: landers.

There are actually quite a few places where you can land a stock ion-engine craft. Here's a few. Pol and Minmus were pretty easy.

polapproach.jpg

Minmuslanding.jpg

Ike is a bit tougher.

IonIke25engines.jpg

I have a thread full of these: http://forum.kerbalspaceprogram.com/showthread.php/30329-Ion-Engines-Everywhere-My-Attempt-to-Land-As-Many-Places-As-Possible

Link to comment
Share on other sites

I can't come up with any other use for them than fine-tuning geostationary orbits. I prefer Hybrid Ion Engines. Still hella efficient but at least you can get something done with them. It's also got scaled up versions of the stock solar panels to supply enough power to the engines (although 2 Gigantor XL's are enough to run one large Hybrid Ion, and if you add a third panel, you can run 2 large hybrids or 1 medium size PB-Ion).

Link to comment
Share on other sites

  • 2 months later...

I've found it takes 16 1X6 lightweight solar panels to power one ION engine reliably at full throttle throughout most of the solar system, including Joon. Using careful planning and minimal parts, I've been able to get TWRs (Kerbin Gravity) up to .06, with nearly 8000 M/s DV. To put it into perspective, that allows me to burn 500 M/s DV in about 13 minutes, give or take. That's short enough to make cruising the moons of Joon fun, and makes exploring the rest of the solar system possible.

My payloads are minimal: gravity probe and a small antenna with no battery. I can send messages back between burns. It's slow, graceful and fun.

Don't mind the random decoupler. I had just finished deploying the ION Sloop in the Joolian system.

screenshot6.png

Link to comment
Share on other sites

I tried one on a solar probe but the burn time was 18hrs to create a circular orbit. Gave up and not used them since.

I am thinking of building an interplanetary ship with 4 or 8 engines but from what I've read I'll stick with nuclear.

Link to comment
Share on other sites

I tried one on a solar probe but the burn time was 18hrs to create a circular orbit. Gave up and not used them since.

I am thinking of building an interplanetary ship with 4 or 8 engines but from what I've read I'll stick with nuclear.

Yeah, ions only really work for light craft... I suppose you could kludge together a dozen engines (with a Gigantor panel each!) to make a hitchhiker go someplace, but it really is a kludge. That being said, I did build "Sunjammer": a mk1 capsule on a stick, with 4 Gigantors and 4 ions on it. Made for a very sedate ride to Minmus and back... didn't try to land, though.

I should probably take a screencap of my Phaeton ion-powered probe awaiting its launch window to Eeloo sometime and post it here; "Mini-Moho" taught me some stuff.

-- Steve

Link to comment
Share on other sites

Visited the Jool system:

buYKIsu.png

Pol orbit:

YHIf97Q.jpg

Pol landing:

MRRNBww.png

The spacecraft itself was still in orbit - Jeb jetpacked down to the surface, and returned to the orbiting spacecraft with about 13% jetpack fuel left. I don't think the ship would have had enough thrust to lift off again.

Link to comment
Share on other sites

I've tried to use it on a minimal weight probe to reach Kerbol after toying with gravity slingshots around the system. It takes a lot of time and it grinds my gears when it loses power because Jool is green and for similar stupid reasons.

It's hard to plan proper burns without software help so you kind of lose the feeling it's a craft you're working with.

Link to comment
Share on other sites

This thread is quite old. Please consider starting a new thread rather than reviving this one.

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...