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[1.12.x] Alcubierre Warp Drive (Stand-alone)


RoverDude

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Hello, I have a quick question! I was wondering if other vessels inside the warp bubble of the active craft follow it through warp. I ask because I jettisoned a decoupler prior to a jump in one of my ships, and after I activated the engine it followed me along at warp speed. It slowly drifted back towards the back of the bubble, and the moment it crossed some invisible threshold, BAM thousands of kilometers behind.

Edited by Dres
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@Dres It very well could. The way the warp drive works now is by shifting the Krakensbane reference frame, so it wouldn't surprise me if it drags everything along within physics range.
Myself, I think that's a kinda cool side effect of experimental technology. If you're warping space that much there should be some unintended side effects like that :)

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  • 3 weeks later...

Wow, RoverDude, I am thoroughly impressed by this mod! I have played with it and have come to this conclusion: It is the best mod I have ever played with. Seriously! KSP is the perfect game for me to figure out warp drive physics, and when I found this mod, the excitement overwhelmed me! Thank you so much for making this mod! :)

:D:D:D

Edited by skylon7
I forgot to add smiley faces
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@RoverDude, hi, I've experienced a bug, when warp drive wasn't working (in warp mode). I was swearing, because lifting up 1200 parts cargo (dozen of probes + uks base parts) takes too long due to parts count. But then I go to VAB and realized that warp drive was the root part of my vessel (and thought that it was a cause). I changed it to command pod and it worked normally.

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3 hours ago, RoverDude said:

Sorry I don't understand the question?

I am experiencing the same issue: the Alcubierre drive does not function correctly if it is the root part of the vessel. When activated, only the Xenon Gas thrusters fire, and the warp function does nothing.

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14 minutes ago, LordKael said:

I am experiencing the same issue: the Alcubierre drive does not function correctly if it is the root part of the vessel. When activated, only the Xenon Gas thrusters fire, and the warp function does nothing.

Are you in high enough orbit?

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FWIW, I have written a kOS script to help with warpdrive navigation, it's goal being to minimize the dV needed to capture at your target.  It follows the approach shown in the KSP wiki, here:  http://wiki.kerbalspaceprogram.com/wiki/Tutorial:_interplanetary_warp.  It will take you to the intermediate waypoint, which changes your direction, and then wait there until solar gravity changes the magnitude of your velocity (usually only a few hours).  It's up to you to get from the waypoint to the target.

However, the pic in the link above is misleading because it shows your ship crossing a line that runs through the sun and is perpendicular to the line from your starting position to the target.  I've found that if you ever cross that line while en route to the waypoint, your ship's orbit changes to solar retrograde and stays that way out to the target, so the minimum capture burn is 2x the orbital velocity of the target, which is of course huge.  This means my script only works if you use special warpdrive-type transfer windows.  Going outwards, you want the target between about 5^ and 35^ behind the continuation of sun-->ship line.  Going inwards, you want the target 5^-35^ ahead of the ship-->sun line.  The closer the target is to this line, of course, the less direction change the ship needs, so the overall trip is a bit shorter.  Still, within these parameters, my script will let you capture for about 1000 +/-200m/s at both ends of the trip, even out to Plock in OPM.  That could probably be fine-tuned a bit.

Is this reliance on launch windows to avoid getting into a solar retrograde orbit an inherent feature of warpdrives and/or KSP, or am I missing something?  I'd of course like to make this script generally applicable so I could go anywhere at any time.  However, I don't mind waiting for transfer windows as long as I can save on travel time, so I'm fairly happy with it as it stands.

This is my 1st semi-complex kOS script and the 1st code I've written in several years.  It's somewhat rough around the edges and definitely needs refinement, most of which is due to my unfamiliarity with kOS.  Right now it works great for small ships but if you've got a monster that takes all day to change orientation, the script at present probably won't wait for the orientation to be complete before kicking in the warpdrive.

That said, I'm looking for advice.  I'd appreciate input from experienced users of this mod (for alternative warpdrive astrogation techniques) and experienced kOS programmers (to help me with the script).  If you want to take a look, it's in my dropbox:  https://www.dropbox.com/s/epqmsuh2t92ym5k/Astrogator.ks?dl=0 

PM me with what you think.  Scathing comments welcome.

Or even better, point me to a completed, competently written script so I don't have to re-invent the wheel :)

And thanks, @RoverDude, for giving me something else to play with and new challenges to overcome.

------------------------------------------------

New subject:

When the warp bubble is active, whether in the VAB or in space, mousing over parts of the ship within the bubble makes them become invisible.  Is that just me or are others seeing this?  I'm seeing this in both heavily modded and minimally modded games.  Can't try it in stock, of course, as this is a mod :)

 

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@Geschosskopf

You have 2 physics options with this warp drive here and both do that, here's why:
When you warp you shift your local area to a new area. This preserves the absolute direction of your velocity vector. When you leave warp you are heading the same direction as when you enter. Prograde on one side of the sun is retrograde on the other, radial at 90 degrees, anti-radial at 270. In velocity preservation your magnitude of velocity remains the same as well. With Angular Momentum mode, you preserve your orbital momentum so that velocity magnitude increases or decreases based on a whole bunch SOI related calculations.

If this were not the case your kerbals would pull a huge number of Gs upon leaving warp. An Alcubierre drive should work without the passengers feeling any acceleration at all. That's one of the emergent properties of developing a warp drive that should behave somewhat as physics may require (if it's possible), launch windows are still a thing unless you have huge amounts of delta-v to spare. That all said... The Angular Momentum mode allows for a lot more things one can do with gravity assists and cleverness to reduce those delta-v needs than the velocity preserving mode.

Edited by helaeon
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@helaeon

Thanks.  I kinda thought it was the retention of your initial vector that made the orbit switch to solar retrograde but wanted to be sure.  KSP does strange things sometimes..

Also, the angular momentum mode is new to me since the last time I messed with this mod.  As usual, I can't find any information on how it works or how you would navigate using that mode.  Please explain that to me.  I also notice that the decision to use 1 mode or the other is made in the VAB because there's no button to switch between modes once you're in space.  Is that supposed to be that way?

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@Geschosskopf
KSP isn't switching the vector. It is actually staying put, and that is very much by design and on purpose.
Picking which physics/behavior you like in the VAB is on purpose. There's a very cheaty (even more so than a regular warp drive) procedure one can do if they can switch between velocity preservation and orbital/angular momentum mode in space. Now, I seem to remember back when I was working on this a ton I set it up so you could save-edit switch modes if necessary. 

The reason both modes are there is/was a very vocal group wanted the old KSP-I behavior (velocity vector preservation)... I thought that mode while much easier to program was not at all how an Alcubierre drive would behave as you gain significant amounts of free orbital energy. It seemed to me that what would be preserved is your orbital angular momentum vector (the vector h, which is actually a KSP function). If you search my user name in this thread you'll get a lot of explanation on the theoretical physics as to the hows and whys behind a lot of this. Roverdude and I decided the best option would be to let people pick their drive in the VAB. You can't do normal algebra on vectors, so in order to not have infinite solutions to the velocity vector upon dropping out of warp, I decided to retain the original direction of travel as well.

You'll see in angular momentum mode if you warp from Kerbin to Jool, you'll get there with far, far, too little velocity to be captured. Rather than far too much in a lot of ways the two modes are opposites. Angular momentum mode works like a Hohmann transfer where you "pay" for the whole trip at the end. Except you have a warp drive - you can use successive warps to capture or magnify the effect of your burns by doing almost all of it very near periapsis (This too is by design - I tested it at Dres to make sure it worked on even a very small body). You're picking up/losing orbital energy by taking/giving it to the nearby gravitational body. Just like a gravity sling-shot because it is one, just a successive one... again by design.

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23 hours ago, helaeon said:

@Geschosskopf
KSP isn't switching the vector. It is actually staying put, and that is very much by design and on purpose.

Fine with me.  Just wanted to be sure switching mode was intended to be only a design decision and not something available in flight.

 

23 hours ago, helaeon said:

The reason both modes are there is/was a very vocal group wanted the old KSP-I behavior (velocity vector preservation)... I thought that mode while much easier to program was not at all how an Alcubierre drive would behave as you gain significant amounts of free orbital energy. It seemed to me that what would be preserved is your orbital angular momentum vector (the vector h, which is actually a KSP function). If you search my user name in this thread you'll get a lot of explanation on the theoretical physics as to the hows and whys behind a lot of this. Roverdude and I decided the best option would be to let people pick their drive in the VAB. You can't do normal algebra on vectors, so in order to not have infinite solutions to the velocity vector upon dropping out of warp, I decided to retain the original direction of travel as well.

You'll see in angular momentum mode if you warp from Kerbin to Jool, you'll get there with far, far, too little velocity to be captured. Rather than far too much in a lot of ways the two modes are opposites. Angular momentum mode works like a Hohmann transfer where you "pay" for the whole trip at the end. Except you have a warp drive - you can use successive warps to capture or magnify the effect of your burns by doing almost all of it very near periapsis (This too is by design - I tested it at Dres to make sure it worked on even a very small body). You're picking up/losing orbital energy by taking/giving it to the nearby gravitational body. Just like a gravity sling-shot because it is one, just a successive one... again by design.

OK, I'll play with the angular momentum version at some point.  It sounds interesting.

Right now, however, I'll stick with the velocity version.  I rather like it because it reminds me of sailing.  With a sailing ship, you almost never take a direction route to your target, you take a route that's a compromise between which way the winds blow and how close your vessel can sail to them.  For instance, to get from England to India in a sailing ship before the Suez Canal, you'd go SW nearly to the coast of Brazil, then SE to 40-50S, then E to Good Hope, crossing the Atlantic twice diagonally because that's how the prevailing winds work.

Visiting the sun en route to/from anywhere seems very much like this to me.  And my space program has always had an Age of Sail ethos complete with pressgangs, lashings, and rum, so this fits right in.  Besides, the KSP universe manifestly runs on totally different physical laws than our own, so I don't feel compelled to make a speculative technology like an Alcubierre drive follow Earthly thinking.  I feel free to imagine it working via "winds" that exist in some sort of "trans-lumineferous aether", which only happens in the strange universe of KSP :)

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  • 2 weeks later...
14 hours ago, magi093 said:

So maybe I'm an idiot for not knowing this, but does the drive have to be in orbit to function? I can't get it to start and stay started at the KSC, even with infinite electricity and propellant on.

You have to be in a rather high orbit for the drive to activate, it will not do so on land or launchpad or atmosphere.

If you intention was easy sandbox travel, you can google hyperedit to get into orbit.

If your intention was to use it legitimately, it can definitely not be used in atmospheres, you have to have standard engines haul it above 5thEDIT: DEFINITELY 900km for kerbin, and activate the warp drive then.

Edited by YagiHige
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21 hours ago, magi093 said:

So maybe I'm an idiot for not knowing this, but does the drive have to be in orbit to function? I can't get it to start and stay started at the KSC, even with infinite electricity and propellant on.

Gosh, you wouldn't want to turn Kerbin inside-out! That's a safety feature! :D But yes, what YagiHige said. :)

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2 hours ago, theonegalen said:

 

Gosh, you wouldn't want to turn Kerbin inside-out! That's a safety feature! :D But yes, what YagiHige said. :)

 

10 hours ago, YagiHige said:

You have to be in a rather high orbit for the drive to activate, it will not do so on land or launchpad or atmosphere.

If you intention was easy sandbox travel, you can google hyperedit to get into orbit.

If your intention was to use it legitimately, it can definitely not be used in atmospheres, you have to have standard engines haul it above 5thEDIT: DEFINITELY 900km for kerbin, and activate the warp drive then.

Thanks. I realized that was the issue, but now I'm not an xkcd punchline.

wisdom_of_the_ancients.png

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So... I like to have my warp drive work at a bit lower of an altitude. Minimum altitude is 1 planetary radius normally (so 600km on kerbin if I remember right), I like half. If you'd like it to be lower you can make yourself a MM patch

@PART[WarpDrive*]
{
    @MODULE[USI_ModuleWarpEngine]{
        @MinAltitude *= .5
    }
}

I put that chunk in my over all module-manager personal tweak patch. If you'd like 1/4 you can do .25. Keep in mind though, warranty void if you do this. Especially if you make the activation distance even lower as crazy unexpected things may happen.

The reason I did this is it makes repeated gravity assists to capture much easier and less repetitive.

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