the ion engine is way too OP

[Levelord]

Yeah, the way it SHOULD work is allowing ion engines to work in on-rails time warp.

There's a mod for that (Orbit Manipulator Series), and I think KSP Interstellar has solar sails that work in on-rails time warp too.

Then drop the thrust to like .01, and then you can use it at 100x time warp and the burn takes 80% of the (real, player's) time it would with a 0.23.5 2kN max-4x-warp ion engine.

That's more of a problem with the game mechanics and interface and less to do with the ion engine.

In terms of dV alone, no, but it DOES change where you can go in terms of being able to land with ions on more bodies.

As I said previously a few pages back addressing this point:

On what bodies? Gilly? Minmus?

All the super low gravity bodies that you can already land on (and take off) using the ant engine (or even RCS) which is faster responding than the ion engine and uses less power and weighs less?

Ion engine spamming doesn't count in the argument, because people can spam any engine to land a lander anywhere. People spam engines for an Eve ascent vehicle, and you can even spam ant engines to land on the Mun.

[hawk_za]

As the ion engine was in the old days i hated it and never used its it,

as it took to damn long to do anything with it.

So i tried it again today and for a tiny probe with a scan sat module and all the small science scanning gear on it (thermometer,gravioli detector etc) and 2 gbig solar panels it still took a 8 min burn to get to the mun.

8 MINUETS of watching a probe burn and managing its power drain that is 8 min REAL TIME,

As in stock mode you cant accelerate time when craft is throttled up ...........NO ion engines are not op they are far more fun now but still 8 MIN to watch a screen real time is a long time,

ksp is a balance of a game and sim key word balance, NOT just a sim id expect the old ion engines to be in a game like take on mars

for now, GO dEVS I'm glad they boosted the ion engines.

[Dodgey]

As the ion engine was in the old days i hated it and never used its it,

as it took to damn long to do anything with it.

So i tried it again today and for a tiny probe with a scan sat module and all the small science scanning gear on it (thermometer,gravioli detector etc) and 2 gbig solar panels it still took a 8 min burn to get to the mun.

8 MINUETS of watching a probe burn and managing its power drain that is 8 min REAL TIME,

As in stock mode you cant accelerate time when craft is throttled up ...........NO ion engines are not op they are far more fun now but still 8 MIN to watch a screen real time is a long time,

ksp is a balance of a game and sim key word balance, NOT just a sim id expect the old ion engines to be in a game like take on mars

for now, GO dEVS I'm glad they boosted the ion engines.

So did you use physical warp? You know, where you hold down the ALT key and press the warp buttons?

[Pockrtplanesairways]

I wonder what propellants the kerbals use. Maybe just LOX and LH, or maybe UDMH and N2O4 like the russians.

Edited April 8, 2014 by Pockrtplanesairways
Incorrect spelling

[coolitic]

As the ion engine was in the old days i hated it and never used its it,

as it took to damn long to do anything with it.

So i tried it again today and for a tiny probe with a scan sat module and all the small science scanning gear on it (thermometer,gravioli detector etc) and 2 gbig solar panels it still took a 8 min burn to get to the mun.

8 MINUETS of watching a probe burn and managing its power drain that is 8 min REAL TIME,

As in stock mode you cant accelerate time when craft is throttled up ...........NO ion engines are not op they are far more fun now but still 8 MIN to watch a screen real time is a long time,

ksp is a balance of a game and sim key word balance, NOT just a sim id expect the old ion engines to be in a game like take on mars

for now, GO dEVS I'm glad they boosted the ion engines.

Yeah, I have rarely used them back then, now a bit more viable.

[technicalfool]

What was the mass of it, and what kind of orbit did it start from? I sun-dived a probe from a Kerbin type solar orbit in way less time than that... didn't keep track, but I don't think it was more than an hour (at x4), maybe more like 30 min?

Found this in the 0.22 installation, I think this is the one. Less engines than I remember, but still. Look at the Mechjeb dV readouts. A fun mission this does not make for.

After looking around, I did find a more-engined affair with rather more solar panels attached, that would have made the sun-dive in a "mere" 8 hours or so.

[Jouni]

Ion engine spamming doesn't count in the argument, because people can spam any engine to land a lander anywhere. People spam engines for an Eve ascent vehicle, and you can even spam ant engines to land on the Mun.

You don't need to spam ion engines to make a lander. My 6.5-tonne Mun lander used 7 ion engines to carry a Mk2 Lander-can to surface and back. The engines fit nicely to the bottom of the ship, and the entire lander was smaller than it would have been with conventional rocket engines. Fuel usage was 10x less than with chemical rockets, which can be important on long-term missions with multiple landings.

I'm not saying that the new ion engines are overpowered. I'm just saying that the update brought ion-powered landers from the realm of extreme sports to the realm of reasonable design choices.

Now we just need bigger xenon tanks to reduce part count.

[Rizendell]

no its not. Its just finally barely fun to use. This isn't a simulation of real life, its a game, games are suppose to be fun, not tediously boring.

[mythbusters844]

At first, people complained that the ion engine had too little thrust to be of any use.

Now, people complain that the ion engine has too much thrust.

Seriously, the ion engine is MUCH more useful now that it's received a thrust increase. Remember: This is a game about sending little green guys into space on huge rockets, not a simulator like Orbiter. Gameplay is more important than realism.

[RocketPilot573]

When the Ion came out, I used it for one mission and NEVER touched it again. At least it's usable now.

[Superfluous J]

"OP" and "finally barely worth using" are not synonyms.

[NERVAfan]

Ion engine spamming doesn't count in the argument, because people can spam any engine to land a lander anywhere. People spam engines for an Eve ascent vehicle, and you can even spam ant engines to land on the Mun.

But ant engines are liquid fuel engines, totally different.

Spamming shouldn't work because the TWR of the engine itself should be too low to land on any significant body, and in that case, adding more doesn't help.

[NERVAfan]

http://i.imgur.com/QaqREB7.jpg

Found this in the 0.22 installation, I think this is the one. Less engines than I remember, but still. Look at the Mechjeb dV readouts. A fun mission this does not make for.

After looking around, I did find a more-engined affair with rather more solar panels attached, that would have made the sun-dive in a "mere" 8 hours or so.

Yeah, that's definitely over-built. You shouldn't have 4 gigantor panels on the thing. 6 of the smaller unfolding panels instead, that's enough to run 1 ion engine at full thrust (or was before 0.23.5 anyway).

EDIT: Not that it's "wrong" as such... but that's why the burns are so absurdly long. Pre 0.23.5 ion engines reward building really light.

"OP" and "finally barely worth using" are not synonyms.

They were totally worth using before, for sun-diving and Kerbol escape.

Beyond those niche roles, there's really no point in them anyway even at 2 kN thrust, since kerbol system dV requirements are so low that you don't NEED better Isp than NTR engines for interplanetary transfers, and they don't work for Eve/Tylo/Kerbin ascents.

Edited April 9, 2014 by NERVAfan
added other quote / reply

[Levelord]

But ant engines are liquid fuel engines, totally different.

Spamming shouldn't work because the TWR of the engine itself should be too low to land on any significant body, and in that case, adding more doesn't help.

Even with a TwR below 1, landing on the moon is still possible, which is for one thing, not a special feature of the updated ion engine. I believe Mublin showcased this with a single LV-909 engine for a heavy Mun lander, all it takes is a shallower descent profile. Doesn't make the LV-909 overpowered because it's capable of doing a low TwR landing.

Regardless, there are so many engines that do a better job than the ion engines at landing that it's only due to pure novelty value that people would decide to use the ion engines as a lander engine in the first place. It's the same reason why you don't see droves of people using the nuclear engines as lander engines on the Mun, even though it can get you around further and works perfectly well as a lander engine.

Mublin's video showcasing this (http://forum.kerbalspaceprogram.com/threads/28073-New-Rebuild!-Apollo-Replica-Munbug-XI-Saturn-V-CSM-Lander-Buggy-and-A-L-S-E-P)

[architeuthis]

The point is that you shouldn't be doing hohman burns at all with ion engines.

What we need is an engine that works during time warp/affects "on rails" calculations.

As it is now, the ion engine acts like a perfectly efficient ion thruster in the 40 MEGAwatt power range, (or more realistically, an ion thruster at 50% efficiency, with a power consumption of 80 megawatts).

Good luck getting 10's of megawatts of power output from solar alone...

Right P=F*Ve/2. Solar isolation works differently enough that solar panels can collect hundreds of times more power than on Earth or the PB-Ion is a perpetual motion machine of the first kind...

I actually don't really mind that, the thing that bothers me is that we use ions for Hohmann transfers in KSP, but that is fundamentally different from how they are used in real life (not just balanced differently). I get it; gameplay, but low thrust is kind of the point of ion engines. The PB-Ion shouldn't be NERVA-lite, why not just ditch it and put in a 'Ant Jr." or some such?

[Jouni]

Regardless, there are so many engines that do a better job than the ion engines at landing that it's only due to pure novelty value that people would decide to use the ion engines as a lander engine in the first place. It's the same reason why you don't see droves of people using the nuclear engines as lander engines on the Mun, even though it can get you around further and works perfectly well as a lander engine.

People use nuclear engines as lander engines all the time. The lander just has to be big enough to make it worthwhile. Because the nuclear engine is big and bulky, it's hard to use it as an inline engine, so most of the time you need at least two of them. That adds 4.5 tonnes of engine mass, which isn't worthwhile in mid-gravity worlds like the Mun, unless the payload is more than that.

Let's look at my ion-powered Mun lander. The payload, including the lander can, lights, landing struts, a docking port, and minimal solar panels, is about 3 tonnes. It has 0.175 tonnes of solar panels, 0.8 tonnes of batteries, 0.84 tonnes of xenon tanks, and 1.75 tonnes of engines, making the total mass around 6.5 tonnes. The lander has over 3200 m/s of delta-v, which is almost enough for two landings without refueling, and definitely enough for hopping around for a while.

We could decide to use conventional rocket engines. With this much payload, the LV-909 is already a better engine than the 48-7S. With one FL-T400 fuel tank, we have 1650 m/s of delta v, which is enough for the landing, but not for any significant hopping. The addition of a second fuel tank increases the delta-v to 2680 m/s, making it about as capable as the ion-powered lander. The total mass of the lander is now over 7.9 tonnes.

The conventional lander is easier to fly due to its higher TWR. It consumes about 2.5 tonnes of fuel in a simple landing, and up to 4 tonnes of fuel during an extended mission. The ion-powered lander uses much less fuel: 0.25 tonnes for a simple landing, and up to 0.49 tonnes during an extended mission. If we want to make multiple landings, refueling the lander at a space station or a mothership, the ion-powered lander is usually the better alternative.

[Levelord]

People use nuclear engines as lander engines all the time. The lander just has to be big enough to make it worthwhile. Because the nuclear engine is big and bulky, it's hard to use it as an inline engine, so most of the time you need at least two of them. That adds 4.5 tonnes of engine mass, which isn't worthwhile in mid-gravity worlds like the Mun, unless the payload is more than that.

Let's look at my ion-powered Mun lander. The payload, including the lander can, lights, landing struts, a docking port, and minimal solar panels, is about 3 tonnes. It has 0.175 tonnes of solar panels, 0.8 tonnes of batteries, 0.84 tonnes of xenon tanks, and 1.75 tonnes of engines, making the total mass around 6.5 tonnes. The lander has over 3200 m/s of delta-v, which is almost enough for two landings without refueling, and definitely enough for hopping around for a while.

We could decide to use conventional rocket engines. With this much payload, the LV-909 is already a better engine than the 48-7S. With one FL-T400 fuel tank, we have 1650 m/s of delta v, which is enough for the landing, but not for any significant hopping. The addition of a second fuel tank increases the delta-v to 2680 m/s, making it about as capable as the ion-powered lander. The total mass of the lander is now over 7.9 tonnes.

The conventional lander is easier to fly due to its higher TWR. It consumes about 2.5 tonnes of fuel in a simple landing, and up to 4 tonnes of fuel during an extended mission. The ion-powered lander uses much less fuel: 0.25 tonnes for a simple landing, and up to 0.49 tonnes during an extended mission. If we want to make multiple landings, refueling the lander at a space station or a mothership, the ion-powered lander is usually the better alternative.

People use the nuclear engine for landers once in a while, but it's never popular enough as a lander engine to warrant people calling it overpowered. The same thing is true with the ion engine and that's the point I was trying to make; It'll never be as popular as conventional engines because conventional engines still do a better job overall.

Bravo, it's nice that you can hop around in your ultra light ion-powered lander all over the mun, but because it has to be ultra light, means that you can't bring any of the worthwhile science equipment down with it (or even return them for that matter). Which makes hopping around to different biomes utterly pointless on ion powered engines. So other than being a nice sightseeing tool of novelty value, the ion engines will never replace the actual usefulness of the conventional engines to carry useful scientific payloads down to the Mun and back.

That is, unless you're going to spam ion engines with solar panels to compensate, then in that case I'll go ahead and spam jet engine intakes and call the jet engines overpowered.

[Jouni]

Bravo, it's nice that you can hop around in your ultra light ion-powered lander all over the mun, but because it has to be ultra light, means that you can't bring any of the worthwhile science equipment down with it (or even return them for that matter). Which makes hopping around to different biomes utterly pointless on ion powered engines. So other than being a nice sightseeing tool of novelty value, the ion engines will never replace the actual usefulness of the conventional engines to carry useful scientific payloads down to the Mun and back.

I deliberately used the heavy 2-kerbal lander can to see if it's possible to build reasonable ion-powered landers. In a science lander, I would use the smaller 1-kerbal lander can, which would free 2 tonnes for the scientific payload. That 2 tonnes could include 5 material bays, 5 goo containers, and a large number of small sensors.

[Levelord]

I deliberately used the heavy 2-kerbal lander can to see if it's possible to build reasonable ion-powered landers. In a science lander, I would use the smaller 1-kerbal lander can, which would free 2 tonnes for the scientific payload. That 2 tonnes could include 5 material bays, 5 goo containers, and a large number of small sensors.

That is, unless you're going to spam ion engines with solar panels to compensate, then in that case I'll go ahead and spam jet engine intakes and call the jet engines overpowered.

How many ion engines does it take for that? 6? 8? 10? and how many solar panels? I noticed you left out the details on how many ion engines you've used for your lander because spamming ion engines to overcome it's low TwR is not an argument that it's overpowered.

[cantab]

Spamming any engines doesn't really overcome a low TWR, since the overall TWR can never exceed that of the engine. Rather, it overcomes a low total thrust and the lack of a scaled-up version of the engine.

[Jouni]

How many ion engines does it take for that? 6? 8? 10? and how many solar panels? I noticed you left out the details on how many ion engines you've used for your lander because spamming ion engines to overcome it's low TwR is not an argument that it's overpowered.

7 ion engines, which fit nicely to the bottom of the lander, and 10 small sets of foldable solar panels. The only thing that feels like spamming is the amount of science stuff in the science version of the lander.

This is an earlier version that didn't have enough batteries, so the command module had to assist in killing horizontal speed:

This is the final version that can land easily on its own:

I'm still not saying that it's overpowered. I'm saying that the update changed the nature of the ion engine so much that it's no longer believable.

[maccollo]

How many ion engines does it take for that? 6? 8? 10? and how many solar panels? I noticed you left out the details on how many ion engines you've used for your lander because spamming ion engines to overcome it's low TwR is not an argument that it's overpowered.

The maximum TWR you can attain at Mun with an ion engine would be 2.6.

Subtracting the mass of the engine, one radial xenon tank, and 8 OX-4 solar panels, one ion engine should have enough thrust to lift 0.76 tons at the surface of Mun at a TWR of >1.

*edit

One thing I realized just now is that since the electric charge consumption was reduced per unit of thrust, the batteries have indirectly been buffed on ion probes. You now get 4 times the delta V per charge, but without any mass penalty.

Edited April 9, 2014 by maccollo

[Comrade Jenkens]

If ppl want to edit their configs of the ion engine to more realistic values and then leave their PC on for 6 months real time for a burn then there isn't anything stopping them doing that.

I just wouldn't consider that fun...

[Superfluous J]

7 ion engines, which fit nicely to the bottom of the lander, and 10 small sets of foldable solar panels.

http://www.cs.helsinki.fi/u/jltsiren/ksp/ion_mun_4.jpg

I'm still not saying that it's overpowered. I'm saying that the update changed the nature of the ion engine so much that it's no longer believable.

What's the dV of that thing? I'm not huge on "everything must be super realistic" and I may build something like this just because I can

[Jouni]

What's the dV of that thing? I'm not huge on "everything must be super realistic" and I may build something like this just because I can

A bit over 3200 m/s. Another limitation is battery capacity: the final lander can use full thrust for at most 5.5-6 minutes at a time, before the batteries run out. After that it will be limited to roughly 1/3 thrust, until it can find time to recharge its batteries.

If you build something like that, remember that low TWR turns a Mun landing into a Tylo landing. (Edit: That's why I don't think that the new ion engines are overpowered. It's not that easy to use them in landers.)

Edited April 9, 2014 by Jouni