Any chance of getting an EM Drive Engine in the future?

[Alshain]

1 minute ago, Sharpy said:

@Alshain: Download and install the mod I posted. Then tell me again it's massively overpowered

Or you could just tell me why you think it isn't overpowered and we could discuss it.  I'm not downloading and installing a mod to prove your point.  The burden of proof is on you.

[Sharpy]

@Alshain

[Alshain]

@Sharpy  I see an overpowered engine compared to the dawn.  What is your point?  Stop trying to be clever and just type the words.

Edited August 31, 2016 by Alshain

[Sharpy]

@Alshain 0.1kN is overpowered according to Dawn's 2kN? At higher own mass, higher power usage, and higher price? Never mind (not shown) considerable cooling requirements?

[The_Rocketeer]

Since a functional EM drive stands to rewrite the book on RL space-travel, I stand right behind @Alshain on the question of whether the game would benefit from this. Essentially the RL propulsion device renders all much of current propulsion tech (on which KSP's gameplay is based) totally obsolete. Don't get me wrong, this is super-exciting for the future of mankind, but KSP is a game based (mostly) on 20th century rocket science, and I think this is an excellent niche for it - recognisable, approachable, and familiar. Too much future-technobabble and the fun takes a nosedive.

[Red Iron Crown]

The mod part shown is interesting, looks like you can't fully eliminate propellant requirements in KSP's engine implementation. So a tiny amount of solid fuel is included with an incredibly high Isp.

(Not a comment on usefulness of the engine itself, just how it had to be implemented.)

[Corona688]

23 minutes ago, Sharpy said:

@Alshain 0.1kN is overpowered according to Dawn's 2kN? At higher own mass, higher power usage, and higher price? Never mind (not shown) considerable cooling requirements?

The issue isn't that it gives too much thrust for not enough power.  (If anything, you overdid that.  It should be maybe 2/3 that of ion for the same power, if the current results mean anything, which is still uncertain.)  The issue is, it produces thrust without reaction.  As current physics goes, it might as well be a warp drive.

Edited August 31, 2016 by Corona688

[Alshain]

20 minutes ago, Sharpy said:

@Alshain 0.1kN is overpowered according to Dawn's 2kN? At higher own mass, higher power usage, and higher price? Never mind (not shown) considerable cooling requirements?

The drawbacks are mostly irrelevant.  In KSP you can use multiple engines and longer burns with physics warp on to get over that effect.  The Dawn engine itself is proof of that, if low thrust engines were and issue, nobody would use the thing.  The gameplay issue is the craft can be used forever (or in this case practically so).  Why would I ever launch a second one?

[Sharpy]

1 minute ago, Alshain said:

The drawbacks are mostly irrelevant.  In KSP you can use multiple engines and longer burns with physics warp on to get over that effect.

You're neglecting the fact even with physics warp this takes over an hour to escape Kerbin in absolutely minimal configuration. And using more engines doesn't really help because that means more "necessities", and very little "spare" thrust. And more parts reduce phys-warp speed too.

Besides, I've shown my point. You show yours. Show me a Kerbal reaching Duna's low orbit using the drive from my mod. Or unmanned probe on Eloo encounter trajectory, capable of performing a capture burn too.

Bonus: make it competitive to alternatives, cost-, time- and effort-wise.

 

4 minutes ago, Corona688 said:

The issue isn't that it gives too much thrust for not enough power.  (If anything, you overdid that.  It should be maybe 2/3 that of ion for the same power, if the current results mean anything, which is still uncertain.)  The issue is, it produces thrust without reaction.  As current physics goes, it might as well be a warp drive.

There are various ion drives, some of them produce micronewtons, some produce as much as 40N. No EM drive went over 0.1N and most tests show something closer to single micronewtons.

As soon as we invent immortality, we may stop caring about TWR.

[tater]

7 hours ago, Xyphos said:

it's real, it exists, it works. I see no reason why we can't get an EM Drive Engine in game.
small, extra-solar probes would benifiet from them

Because it's not demonstrated to be real. It might be, we don't know. Saying otherwise is showing severe bias, in fact, people who know are fine with "we don't know" as a legitimate answer.

Also, like ion engines, it's pointless in KSP because we do not have constant thrust trajectories as a thing.

Edited August 31, 2016 by tater

[Corona688]

1 minute ago, Sharpy said:

There are various ion drives, some of them produce micronewtons, some produce as much as 40N.

I based my comparison off of thrust-per-watt, not thrust in general, and used real numbers -- Deep Space 1 vs the first EMdrive.  Going by that, emdrive is some weaker but less than an order of magnitude.

[Alshain]

11 minutes ago, Sharpy said:

You're neglecting the fact even with physics warp this takes over an hour to escape Kerbin in absolutely minimal configuration. And using more engines doesn't really help because that means more "necessities", and very little "spare" thrust. And more parts reduce phys-warp speed too.

Time is not a factor.  Either you have a patient player that will wait the time, or an impatient one that will never use the part.  So it's either overpowered or not useful depending on the player.

11 minutes ago, Sharpy said:

Besides, I've shown my point. You show yours. Show me a Kerbal reaching Duna's low orbit using the drive from my mod. Or unmanned probe on Eloo encounter trajectory, capable of performing a capture burn too.

Bonus: make it competitive to alternatives, cost-, time- and effort-wise.

You really don't get this burden of proof thing, do you?  I have no reason to do that.  You are the one that wants it in the game, it's your job to prove it belongs there.  You haven't done that (in my opinion).   You have to convince me to have me change my view (but just my view, of course you don't have to convince me at all to have it implemented, you have to convince Squad)

Edited August 31, 2016 by Alshain

[Sharpy]

7 minutes ago, Corona688 said:

I based my comparison off of thrust-per-watt, not thrust in general, and used real numbers -- Deep Space 1 vs the first EMdrive.  Going by that, emdrive is some weaker but less than an order of magnitude.

The problem lies in "the first EMdrive." NSTAR dry mass (tank included) was of order of 50kg, wet - closer to 130kg, the first EMdrive was 300kg. And its results were never repeated - it seems THAT was an error and a fluke; thrust was detected, over and over in numerous experiments worldwide, but two orders of magnitude lower.

[steuben]

A similar question can be asked with a craft with a drill and ISRU. You can refuel it wherever, so it can be used forever. So why launch more than one? Seems like a cooked carrots position.

As for implementation it is possible to have a completely fuelless engine, the blueprints are here:
 

You`ll have to gut a dawn engine to build it. But, no hacky things with solid fuel ISP. Is it balanced? Well, that`s what SAS is for.

As for the two real questions, balance and in stock.

This type of engine walks a fair bit of a knife edge in terms of balance. Slap a few solar panels on it, and see the stars... except for that pesky inverse square thing that light does. I'll just add a few RTGs to it... here comes our old friend Mass Spiral. Well, let's slap on a few fuel cells and some LfO... except what is real ISP using that  FC-LfO combination? Maybe a simpler rocket might be better. Choosing the right balance of thrust to Ec/s to heat to mass will be the challenge.

As for in stock? Maybe as a level 12 tech with a 6 digit science cost and the blueprint from the monolith on Eeloo. But, then if you can do that it will be pretty much a Bragging Rights Reward doing it in either science or career.

[Sharpy]

@Alshain: If time is not a factor, why isn't everyone using nothing except Dawn after unlocking it?

And apparently I don't understand this burden of proof thing.

You make an opinionated statement.

I counter with a concrete example.

You express a baseless opinion that my example is invalid.

I explain how it's valid, supporting this with facts.

You express another, completely erroneous opinion, and demand I provide more proofs.

No. It's time you provided some proofs. Show me an example scenario where my mod drive is totally overpowered.

 

Unless the "burden of proof" thing is a strictly one-sided thing, where one side provides factual examples, and the other keeps making claims without ever supporting them with facts. After all, I'm supposedly not getting it.

[Corona688]

2 minutes ago, Sharpy said:

And apparently I don't understand this burden of proof thing.

You create the mod, you demonstrate it's not OP.  Put it through its paces, show it off.

RTG + emDrive = infinite dV, however, which is the fundamental problem with the concept.

 

[Sharpy]

14 minutes ago, Corona688 said:

You create the mod, you demonstrate it's not OP.  Put it through its paces, show it off.

RTG + emDrive = infinite dV, however, which is the fundamental problem with the concept.

 

Well, I would. Except I can use the computer where I play KSP for maybe 4 hours a day. I'd need to sacrifice a good fourth of that to demonstrate futility of that approach. And THIS is precisely the factor that limits its usefulness: People have lives. They are not going to spend an hour doing nothing except switching the engine on and off as it passes the periapsis, when they can achieve the same with other parts within five minutes.

In the "general scenario" it can be used to escape the system, or descend to the Sun. But if you want to reach any *specific* destination, you need a semblance of precision. How are you going to achieve that? The game does not provide continuous burn planning, just point burn nodes which you approximate with short, intense burns. You can approximate them with multiple short burns too. But that takes time - a lot of time. Just pressing Z and going to a pub will get you nowhere. All the delta-v in the world won't fix your encounter if your TWR is of order of 0.01 and you have only the evening to do it.

[Corona688]

27 minutes ago, Sharpy said:

Well, I would. Except -

Fair enough, but there's things you might not realize.  The rocket equation is a tyrant.  Its penalties grow exponentially and impose hard limits on what is possible.  Even ion drives only spare you a tiny bit, still being reaction drives.  EmDrives are completely exempt from the tyrant -- the weight to power and cool one forever is constant, which violates conservation of momentum.

Conservation of momentum is a rule which prevents us from building perpetual motion machines.  Throw it out and you open the door to shenanigans, by definition.  Someone will figure out a legit way to turn it into a star-crosser.

The limits you impose don't really matter, as the penalties only stack linearly.

Edited August 31, 2016 by Corona688

[Alshain]

1 hour ago, Sharpy said:

Well, I would. Except I can use the computer where I play KSP for maybe 4 hours a day. I'd need to sacrifice a good fourth of that to demonstrate futility of that approach. And THIS is precisely the factor that limits its usefulness: People have lives. They are not going to spend an hour doing nothing except switching the engine on and off as it passes the periapsis, when they can achieve the same with other parts within five minutes.

In the "general scenario" it can be used to escape the system, or descend to the Sun. But if you want to reach any *specific* destination, you need a semblance of precision. How are you going to achieve that? The game does not provide continuous burn planning, just point burn nodes which you approximate with short, intense burns. You can approximate them with multiple short burns too. But that takes time - a lot of time. Just pressing Z and going to a pub will get you nowhere. All the delta-v in the world won't fix your encounter if your TWR is of order of 0.01 and you have only the evening to do it.

Ok, so lets just say for a moment they won't spend that time (I know they will cause they do it now with the Dawn, but for the sake of argument)... then why do we need it at all?  You are saying it isn't overpowered because people won't use the engine.  What incentive is there to add something people won't use?

More importantly, what is it's niche.  Why do we need this thing? What purpose does  it fill that no other engine in the game can fill?

Edited August 31, 2016 by Alshain

[Sharpy]

Actually, I realized I don't need to perform the burn. All I need is to have KER calculate it for me.

It uses HECS, which provides basic SAS nodes, but doesn't weight more than necessary. I could have saved 0.1t by using OKTO2 and a small reaction wheel, but then SAS would be nearly unusable due to way too high torque, and also power draw would be higher, necessitating either throttling it deeper, or adding yet another RTG, completely obliterating any mass benefits.

The probe has the basic four "lightweight" science devices, and the light antenna. Two panels as necessitated by the drive, and 18 nuke batteries, allowing it to run at 98.5% throttle with the panels operating. Any SAS activity during the maneuver drains the probe's battery, but during idle time it refills slowly.

 

It's the optimal transfer window to Eeloo, Year 1,day 246 according to the planner. I've set up the departure node accordingly.

 

Please note the Node Burn Time in the KER window, in the Node section.

1d 5h 18m 8.6s

Converting from Kerbin time to seconds, that's 40688.6s, or about 11 hours 18 minutes our time.

At phys-warp running x4, you reduce that time to 2 hours 50 minutes of gameplay time, to perform this operation - assuming your computer can run phys-warp at 100% speed.

This is just to achieve the delta-V, ignoring the fact you need to modify the burn to account for orbital curvature; after all, that's nearly 20 orbits in LKO. This is not going to a pub for two and a half hour. It's actively adjusting the burn every time you circle Kerbin, switching the engine on and off, and in general spending roughly three-four times that time performing the operation.

Do you really claim the infinite delta-V outweighs benefits of alternatives of higher thrust in such a situation? Or can you suggest a scenario, where the shortcomings wouldn't be as aggravating?

 

I can. The "Solar Limbo" challenge. Much reduced number of solar panels, necessity to use radiators anyway, and a very simple burn scheme that can be left unattended for hours, plus massive delta-V requirements. But that's a very unique, specific scenario that doesn't apply in great most cases - and as any balanced part, this one has a few situations where it shines, and many where it's crap. If it was overpowered, it would shine in any situation. E.g. multi-kerbal Tylo landing. Try to think up a configuration where it would make ANY sense in this scenario. Because seriously, I can't.

43 minutes ago, Corona688 said:

Fair enough, but there's things you might not realize.  The rocket equation is a tyrant.  Its penalties grow exponentially and impose hard limits on what is possible.  Even ion drives only spare you a tiny bit, still being reaction drives.  EmDrives are completely exempt from the tyrant -- the weight to power and cool one forever is constant, which violates conservation of momentum.

So are ISRUs as long as they have anything to scoop. In all reasonable KSP scenarios they do.

10 minutes ago, Alshain said:

Ok, so lets just say for a moment they won't spend that time (I know they will cause they do it now with the Dawn, but for the sake of argument)... then why do we need it at all?  You are saying it isn't overpowered because people won't use the engine.  What incentive is there to add something people won't use?

More importantly, what is it's niche.  Why do we need this thing? What purpose does  it fill that no other engine in the game can fill?

Oh, no. I'm not arguing the opposite side with you. I have my ideas for its niches, but I leave it to players to think them up themselves.

I'm saying it's not overpowered, because in the general use it's useless. But there ARE niches where it's useful. I'm not telling though; this is not the argument I want to have.

[DaMachinator]

4 minutes ago, Sharpy said:

This is just to achieve the delta-V, ignoring the fact you need to modify the burn to account for orbital curvature; after all, that's nearly 20 orbits in LKO. This is not going to a pub for two and a half hour. It's actively adjusting the burn every time you circle Kerbin, switching the engine on and off, and in general spending roughly three-four times that time performing the operation.

Do you really claim the infinite delta-V outweighs benefits of alternatives of higher thrust in such a situation? Or can you suggest a scenario, where the shortcomings wouldn't be as aggravating?

And this is the reason it shouldn't be in the game.

[Sharpy]

3 minutes ago, DaMachinator said:

And this is the reason it shouldn't be in the game.

I won't argue this. Some people claim Thud or Spider shouldn't be in the game, others think ISRU is just an unnecessary fluff, yet others consider the ion drive useless. These are all personal opinions stemming from personal preferences. There are people who disagree.

It's definitely far, far less useful than my two "rivals" tried to make it out to be, but you must take my word that I believe it has meaningful uses.

ps. Should it be stock? Hell no. Is the mod a complete waste of time? That depends only on your creativity.

Edited August 31, 2016 by Sharpy

[DaMachinator]

1 minute ago, Sharpy said:

I won't argue this. Some people claim Thud or Spider shouldn't be in the game, others think ISRU is just an unnecessary fluff, yet others consider the ion drive useless. These are all personal opinions stemming from personal preferences. There are people who disagree.

It's definitely far, far less useful than my two "rivals" tried to make it out to be, but you must take my word that I believe it has meaningful uses.

You literally just said it doesn't, apart from sundiving?

[Corona688]

10 minutes ago, Sharpy said:

So are ISRUs as long as they have anything to scoop. In all reasonable KSP scenarios they do.

No, they're not.  You have to get the fuel to the rocket, and the longer it fires, the further away it will be.  It's still subject to the tyrant.

There's exactly one scenario that doesn't apply, asteroids, which are fuel-limited.

 

 

Edited August 31, 2016 by Corona688

[Alshain]

14 minutes ago, Sharpy said:

Oh, no. I'm not arguing the opposite side with you. I have my ideas for its niches, but I leave it to players to think them up themselves.

I'm saying it's not overpowered, because in the general use it's useless. But there ARE niches where it's useful. I'm not telling though; this is not the argument I want to have.

Well if you can't say what it is to be used for I wouldn't count on it being implemented.  I don't speak for Squad, mind you, but I've never known them to implement a request from these forums that has absolutely no known uses.

As far as overpowered goes, you seem to be under the assumption that means a trip to Eeloo.  That is simply not the case.  It can be overpowered without ever leaving Kerbin's SOI.  Infinite fuel is overpowered in the gameplay structure we have.  There is no risk for reward, I have a satellite contract, I can screw it up all I want because I never run out of fuel, I have infinite attempts to get it right.  That is bad gameplay.

Edited August 31, 2016 by Alshain