Sadness. Just found another thing that was broke in 1.0

[basic.syntax]

Yes.

Arguing that the game has 'goofy kerbals and unrealistic physics" is to miss the point.

There should be allowances to make the game more playable -like timewarp, and the high thrust ion engines. But proper representation of space flight should win over making anything doable. Things like ion engine landers should be notable because they work in spite of how hard it would be.

That said, I wouldn't mind them being given an atmospheric thrust of 0.2, or 0.5. They'd still be almost useless in atmosphere, but people did manage to make things which could fly with ion engines before the 23.5 thrust boost.

Though I support KSP willingness to expose players to various real tech concepts with a "game first, realism close second" approach, I actually like the new atmo thrust curves for different engines, and ions especially. It's a nod to reality that they are useless in atmosphere now, while preserving their usefulness in game terms for space probes. KSP players still learn, proportionally speaking, that Ion drives are low thrust and high ISP. I'd support taking their thrust down to nearly realistic levels, if Squad were to face the programming challenge of thrust on rails in timewarp. But I'd have (additional) mental troubles with going all the way to reality, in the Stock game. 10 years of timewarp for one burn would start pushing my "Are we there yet?" gameplay button.

Thanks Nova, for sharing your original design intent. Reading these forums is like a never-ending treasure hunt, you never know what nuggets of KSP backstory you might uncover.

[NovaSilisko]

That's ion engines currently available today on Earth, but there's an awful lot of future out there, we might easily make a better one. And who knows what little green men from another world might have figured out to get decent power density out of an ion engine?

No, I'm fairly certain there's actually a physical hard limit for how much thrust ion propulsion can produce. It's only a few newtons at the theoretical maximum, I think. I can't remember the mechanism that restricts the thrust but I know there is one.

[OddFunction]

No, I'm fairly certain there's actually a physical hard limit for how much thrust ion propulsion can produce. It's only a few newtons at the theoretical maximum, I think. I can't remember the mechanism that restricts the thrust but I know there is one.

Is this where quantity over quality kicks in?

[NovaSilisko]

Is this where quantity over quality kicks in?

Well, as XKCD What If taught us with its lovely AK47 rocket space platform thing, there's a maximum thrust-to-weight ratio that can be achieved for any engine. As you add more and more and more and more engines, you only can ever achieve the thrust to weight ratio of a single, unladen engine. Which, if your engine has peanuts for TWR already (like an ion engine) means you can never get very high acceleration from a low-thrust engine, no matter how many you put on. The thing is, KSP's ion engine has a very very high TWR, which means, in the context of the game, you CAN stack them to get fairly high acceleration.

[Red Iron Crown]

It's the charge, you can only ionize xenon so much. More energy lets you ionize more of it, but it doesn't give more charge to the individual ions.

That is more of an Isp limit than a thrust limit, though.

[Laie]

It's the charge, you can only ionize xenon so much. [...]

That is more of an Isp limit than a thrust limit, though.

Exactly. There is no ultimate limit to the amount of stuff you toss out in a given timeframe. However, if you want to scale it up, you start to get a *lot* of waste heat: you can only put so much power through a coil before it begins to melt. Thicker wires no good, putting many in parallel no more efficient.

If you want considerably higher thrust, it will probably be easier to skip the electricity -> magnetism step and just heat the atoms directly. You'll lose some ISP, but gain a lot in thrust.

Hmm. Sounds familiar.

[Foxster]

No, I'm fairly certain there's actually a physical hard limit for how much thrust ion propulsion can produce. It's only a few newtons at the theoretical maximum, I think. I can't remember the mechanism that restricts the thrust but I know there is one.

...Videre, sed etiam illa, quæ futura sunt. Edited June 8, 2015 by Foxster
cos

[basic.syntax]

JPL's Dawn site has an excellent ion engine educational section.

[sal_vager]

Videre, sed etiam illa, quæ futura sunt prospicere.

See, as well as those that are to come to look.

Quaint

[regex]

Truly what KSP needs is more magical engines because LGM.

[Laie]

school was long ago, but I can still remember that one: "true wisdom is not only seeing what's in front of your feet, but also anticipating what could be in the future". Foxster appears to demant future tech. He also has truncated the first half of the quote.

[NovaSilisko]

So a complete handwaving away of limitations by saying "eh whatever people in the future will figure something out, you can't prove me wrong", then?

[Foxster]

So a complete handwaving away of limitations by saying "eh whatever people in the future will figure something out, you can't prove me wrong", then?

Something like that, yes. But (almost) seriously...ion engines used to work one way in the Kerbal's universe but now they work a different way. Who is to say what those wacky guys will come up with next?

[regex]

So a complete handwaving away of limitations by saying "eh whatever people in the future will figure something out, you can't prove me wrong", then?

"Any resemblance to existing technology that may bear the same name or work in roughly the same manner is purely coincidental."

Clearly the LV-N running hot isn't a problem.

[Beowolf]

Exactly. There is no ultimate limit to the amount of stuff you toss out in a given timeframe.

Respectfully, no. Such "ultimate limits" are built-into the very fabric of our universe.

For example, there are ultimate limits on how quickly you can pump a liquid. Liquids have mass and inertia and don't like going around corners. On rocket-science scales, it doesn't take long at all for the pressures to exceed anything that a turbopump made of matter can withstand. When turbopump turbine blades made of diamond can't handle the load, you need magical sci-fi tech.

But if you have the tech to build turbines out of force fields or some such, what do you still need a primitive ion engine for?

Everything in chemistry and physics has ultimate limits, because our universe's four fundamental forces came with limits pre-installed by the factory.

[Foxster]

Clarke's Three Laws:

1. When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong.
   
2. The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
   
3. Any sufficiently advanced technology is indistinguishable from magic.
   

[Wjolcz]

Rather late response to OP: We don't need no Ion ISP buffs. What we need for Duna's atmosphere (and other atmospheric bodies) is a single part called electric propeller.

Unless you want to get back to orbit from the surface. Then you take with you some old fashioned chemical engines.

[Hotaru]

Any sufficiently advanced technology is indistinguishable from magic.

As much as I like Clarke, that just means that where a fantasy writer handwaves a story mechanic by saying "it's magic," a sci-fi writer can do the same by saying "it's advanced technology." The logic is, if a computer would be as good as magic to a cave man, so futuristic or alien technology would be as good as magic to us. It doesn't apply to something like KSP, which sticks to present-day or near-future technology--technology that is decidedly un-magical to someone who understands the engineering behind it.

In my mind there's three levels of science-fictional technology. One is technology is known to be possible, the next is technology not definitively proven to be impossible, and the last is technology that is impossible as we currently understand it. Some (be honest, most) science fiction uses all three, some uses only the first two, but KSP as it stands now uses only the first: technology that has either already been used (most of it), or is within one technological generation of being used (Rapiers, NTRs, etc.). As soon as we start allowing "indistinguishable from magic" sci-fi handwaving, we might as well add in warp drives, anti-gravity, and teleportation to go along with our high-thrust ion engines.

One thing I like about KSP is using things for other than their intended purpose. If an ion lander is possible within the rules of the stock game, we should build it even if that's not what the ion engines were meant to do. But I won't shed any tears to see it get "broken" in the name of realism, because in real life, using an ion engine to land on anything bigger than a very, very small asteroid is--if not impossible--at least not known to be possible.

As far as the actual engine goes--would reducing its unladen TWR help? Reduce its thrust a bit, and/or make it a little heavier. Maybe increase its Isp a little to make up for it. Not a dramatic change, but just enough to make a TWR > 1 impossible anywhere except perhaps Gilly, Bop, or Pol.

[Falconer]

Gotta agree with most... while cute the ion landers don't really fit in the game well. Their thrust is too high.

All attempts to fix only ion engines kind of miss the point IMO. Simply fixing the ability of all ships to thrust while on rails would do a lot of good.

Also the tech tree really is missing some items which really should also be in here.

Propellers, Rotors, and balloons. Yes they only work in atmospheres... but they work in non-oxidized atmospheres as well as oxidized ones. So far the atmopheric parts really only involve Kerbin and Leythe... People forget unpowered rotors double as parachutes.... and can make autorotation landings... (personally think gyrocopter is great pick for moving around some of the atmospheric biomes, though most people don't understand how they function differenty than helicopters). Instead we need to rely on inefficient rockets and only rockets (and the stupidly broken 1.0 ion) to push us through.

[FleshJeb]

No, I'm fairly certain there's actually a physical hard limit for how much thrust ion propulsion can produce. It's only a few newtons at the theoretical maximum, I think. I can't remember the mechanism that restricts the thrust but I know there is one.

http://en.wikipedia.org/wiki/Dual-Stage_4-Grid

The PDF linked in footnote 1 was fascinating. It looks like the limiting factor is the weight of the power generating equipment. "25 kg/kW or less"

[Foxster]

...doesn't apply to something like KSP, which sticks to present-day or near-future technology--technology that is decidedly un-magical to someone who understands the engineering behind it.

You mean like how entire space rockets, planes and their fuel can be built out of thin air in an instant, with no other infrastructure on the planet? Or how the planets are on rails and the sun has an infinite SOI? Or that the universe's physics, planets' characteristics and how engines work changes every few months? Or that infinite ore can be wished out of the ground? Or where magic spinning boxes can right your craft? Or where the crew never eat, drink or defecate? Or where fuel can be magically created from rocks? Or where a claw can make two craft become one with fuel cross feeds?...

Its a game, not a simulation. Whatever is needed to make it interesting or fun is implemented. So, ion engines lifting a 100t rocket from sea level, why not? Who's to say what is impossible in the Kerbal-verse?

[r4pt0r]

Its a game, not a simulation. Whatever is needed to make it interesting or fun is implemented. So, ion engines lifting a 100t rocket from sea level, why not? Who's to say what is impossible in the Kerbal-verse?

Because that particular example would be terrible and shatter all suspension of disbelief and immersion in the game.

Please for the love of Jeb be posting this ironically. You cant really think this right?

[regex]

Please for the love of Jeb be posting this ironically. You cant really think this right?

They think engines should be used based on their aesthetic properties rather than whether they're appropriate to a situation, what makes you think they're being ironic?

[Sandworm]

You mean like how entire space rockets, planes and their fuel can be built out of thin air in an instant, with no other infrastructure on the planet? Or how the planets are on rails and the sun has an infinite SOI? Or that the universe's physics, planets' characteristics and how engines work changes every few months? Or that infinite ore can be wished out of the ground? Or where magic spinning boxes can right your craft? Or where the crew never eat, drink or defecate? Or where fuel can be magically created from rocks? Or where a claw can make two craft become one with fuel cross feeds?...

Its a game, not a simulation. Whatever is needed to make it interesting or fun is implemented. So, ion engines lifting a 100t rocket from sea level, why not? Who's to say what is impossible in the Kerbal-verse?

For multiple reasons, it's a simulation. For instance many of KSP's "game" shortcomings have been replaced with more realistic physics. Take the ISP inversion. For years engines maintained constant thrust, with fuel flow changing with atmo pressure. Many called that a compromise for "game" over simulation to make launches more consistent in different atmospheres. In reality it seems that whomever wrote the original code simply did not understand ISP. So now with 1.0 it has been "fixed" and replaced with more realistic physics. If KSP was only a "game" there would be no reason to fix such errors, or at least not replace them with more realistic physics. Therefore KSP is something more than a game.

"It's only a game" is the battle cry for those who once said "It's still alpha". Virtually any argument can be dismissed with "It's a game" because it places the whims of the devs above any and all other opinions. It means that the devs can do no wrong because KSP has no basis in the real world whatsoever. Such arguments boarder on fanboyism. I have some respect for the Devs, not total adoration, but enough to deffer to them on how to define KSP. And they have for years stated repeatedly and consistently that KSP is no mere game, that "simulation" really is its defining trait.

Edited June 9, 2015 by Sandworm

[basic.syntax]

Foxster is right that the game has many hand-waves and concessions to gameplay. You kind of answered your own question, observing that planets and engines see changes from time to time - Squad gets to say what is impossible in the "stock" game. Complaints about this change don't seem to be gaining traction. It's not rising to the level of a "Save the Round-8" outcry. Players who want the old ability will have to look into cfg editing or mods.