eggrobin

Yes, and for once, I have a reason to write an integrator (something that was severely lacking from my Numerical Mathematics courses). How do you deal with the accumulation of unit roundoffs? On this kind of number of steps, this can become very significant... I use simple compensated summation when accumulating the steps, but not within the actual Runge Kutta stages. Depending on your number of steps, perhaps doubly compensated summation might be worthwile. I'm very worried about the outliers in the errors in H, p and L though (bear in mind that this is sampled down by a factor of 100, so there are probably more of those). I suspect something is coming to close to 0, though I'm not sure why my integrator goes mad in those circumstances. This is v0.1, with an added satellite and both Bop and Boepli. Again, the Mun's trajectory is highly chaotic, it changes significantly over a year between a 10s and a 1s time step, so I'm not sure much can be deduced from that. I think the intent was to replicate the Io-Europa-Ganymede resonance, but that would probably help.

I switched to doing the simulation using a fifth order symplectic integrator (coefficients from The accuracy of symplectic integrators, Robert I. McLachlan and Pau Atela (1992)) that I just wrote in C#: it's faster, 1 year in 149 s with a 10 s timestep, and it's symplectic, which can't be a bad thing. Below are some results from a 1-year simulation with a constant 1 s time step, downsampled to 100 s for plotting due to memory usage. The Mun hasn't quite escaped, as seen from the kinetic energy plot, but is well on its way. The Mun's trajectory is highly chaotic: in a previous simulation where I encountered some issues with the sun (my integrator doesn't like stuff that has velocities/positions close to 0), the Mun made a close Kerbin encounter (certainly below the Roche limit, probably a collision). While Boepli (this is what I called the small version of Bop) had its inclination significantly altered (last picture in the album), it fared pretty well despite the close encounter with such a large body. Similar conclusions hold for the 5t satellite in equatorial circular 100km Kerbin orbit that NovaSilisko asked me to add to the simulation. It seems Kerbin orbit is a very safe place. Finding a configuration for the Jool system that makes the Mun more stable would be an interesting exercise.

I'm not using a symplectic integrator at the moment, I had trouble getting Mathematica to use one. I might want to try again. As a result, the energy error is a drift (the plot is pretty boring, the relative error as a function of time is roughly affine). The energy of the system increases. I can control the solver in Mathematica. This is not the problem. Understanding what the settings do, however, seems nontrivial... Regarding Minmus, it seems I typed in the inclination.

This probably makes more sense. Bad plotting happens. I should increase PlotPoints (MaxRecursion is already at 15). More on the 'orbiting the sun' bug. It seems in the scenario you describe (reload a save with a ship in Kerbin orbit) is the ship's fault (the bodies are where they should be). It occurs after reloading the save, and after restarting the game (exiting to main menu and going back to the save won't do it). These are the orbital elements after restarting the game, but before opening the save (Looks correct): ORBIT { SMA = 680021.630935808 ECC = 4.22982001551599E-05 INC = 0.0886935965917476 LPE = 123.812416691305 LAN = 303.763776806527 MNA = 2.79772644965481 EPH = 159722.345319818 REF = 1 } After opening the save (this is a highly eccentric orbit around the sun, with its aphelion twice that of Tylo; the ship is around the position of Jool at UT = 0 s): ORBIT { SMA = 26727254086.9888 ECC = 0.999040655797898 INC = 6.04635789986987 LPE = 176.48236550725 LAN = 5.1220573694153 MNA = 6.1027150029262 EPH = 1915783.09934322 REF = 0 } I'm not sure where such an orbit could be coming from...

O, that way madness lies. More data from the 10-year simulation (Besides the fact that it takes an eternity and a half for Mathematica to generate a video from the animations it shows me, I can't find a good solution for the Jool system animation: if I run it faster than 50 000x it is illegible, but at 50 000x it lasts 1 h 45 min): A new and improved table of the kinetic energies (I left out Eeloo last time, the bodies are now shown depth-first, increased the MaxRecursion so the plots look decent), and a huge (10 000 x 1 000) speed plot (excluding the sun). EDIT: I'm a bit puzzled by the low-frequency component in Eve's kinetic energy... Could that be the influence of the Eeloo-Vall system?

@NovaSilisko I'd like to look into it (now I have an easy way of knowing where the planets should be, by just adding n*t to the mean anomaly and plotting), but I would need some steps to reproduce (preferably on a stock + Alternis install), as well as the current state of PlanetShifter.cs. @shrx, thanks! I'm not sure how this would affect the already slow integration though.

The question is, who is to blame? The planets, or the ship?

I'm using Mathematica's NDSolve (the thing decides what integrator to use and is typically smarter than I am in this regard), the Mathematica file is in the Google Drive folder I just added to my signature (this is the very file I'm working on, so it will sometimes contain random stuff). There's also a .mov file showing the my 10-year simulation. I tried to make it somewhat readable, but you will need Mathematica to use it (you can view some of it with the Mathematica Player, I think). A student (may be free, depending on your institution) or home ($221.25) edition will do. "Curiously enough, the only thing that went through the mind of the bowl of petunias as it fell was 'Oh no, not again'. Many people have speculated that if we knew exactly why the bowl of petunias had thought that we would know a lot more about the nature of the Universe than we do now." Why is the MET 4h? EDIT: explanation of the animation (https://docs.google.com/file/d/0B4y-shYXMH9BemczakhacjZqMFU/edit) The orbits are the 2-body ones at t=0, the dots are the bodies. EDIT2: I added a pdf generated from my Mathematica notebook in case someone needs it. EDIT3: Mathematica crashed while generating the pdf. I need to re-run the simulation... EDIT4: Happy new year! EDIT5: Whenever you get the 'spawning in solar orbit' bug, take a screenshot of the solar system (with jool and the inner bodies visible) and of the jool system; also note the universal time. Comparing this with the orbital elements from the source, it should be possible to see whether the planets are where they should be.

Preliminary conclusions from a 10-year (315 Ms) simulation, |ÃŽâ€E|/E0 < 2E-7, ||ÃŽâ€p||/||p0|| < 1E-12, ||ÃŽâ€L||/||L0|| < 1.2E-9: The Jool system loses the Mun a bit after 10 Ms and Bop around 175 Ms. Pol's orbit seems to have moved a bit, but it may stand a chance. Laythe, Kerbin and Minmus are very stable. The Tylo system doesn't seem to move much, I haven't looked at it closely. I'm still trying to make gifs out of my animations, but plots of the kinetic energies will have to do for the moment.

It's complicated. At the moment (v0.0), the in-game positions of the planets are as good as random, and this causes the spawning in space bug. Stock anomalies + the M0s I gave is what you get from v0.0 + the anomaly fix. This is what I am using at the moment. To clarify: Body M0 a e É / ° i / ° Ω / ° -------------- -------------- -------------- -------------- -------------- -------------- -------------- sun 0 0 0 0 0 0 9 moho 3.1400000 4.2750404 10 0.40000000 15.000000 0.25020000 70.000000 9 eve 3.1400000 8.1855503 10 0.0080000000 0 1.0200000 15.000000 7 mun 1.7000000 4.3152000 10 0.0020000000 0 0.10900000 180.00000 7 kerbin 3.1400000 6.8506000 10 0.020000000 0 0.40000000 0 7 duna 3.1400000 3.4598850 10 0.050000000 0 0.70000000 135.50000 11 ike 2.8727251 1.6798808 10 0.95850000 0 28.450000 0 10 gilly 6.1508858 3.4084735 10 0.97050400 79.080000 225.05000 25.300000 7 minmus 0.90000000 1.4740300 10 0.030000000 38.000000 0.030000000 78.000000 10 jool 0.10000000 1.3605008 10 0.017000000 0 1.9570000 0 10 tylo 3.1400000 2.4708887 10 0.030000000 0 1.2200000 0 6 vall 0.90000000 4.9950400 10 0.011000000 0 2.3370000 0 7 dres 3.1400000 1.7580043 10 0.0020000000 90.000000 0.10900000 280.00000 7 laythe 3.1400000 2.7184000 10 0 0 0 180.00000 8 bop 0.90000000 1.2850000 10 0.090000000 25.000000 0.89400000 10.000000 8 pol 0.90000000 1.7989000 10 0.083000000 15.000000 4.2500000 120.00000 10 eeloo 3.1400000 9.0118820 10 0.080000000 260.00000 1.1500000 50.000000 This is very strange. I don't have any collision detection, but the general behaviour is very different in my simulation over 500 days (|ÃŽâ€E|/E0 < 2E-8, ||ÃŽâ€p||/||p0|| < 5E-13, ||ÃŽâ€L||/||L0|| < 1.5E-10, I finally figured out that the reason I thought my energy was way off was that I counted potential energy twice). The Mun runs away around t=1.5 Ms t=15Ms (EDIT: I can't count ), and the Jool system stays very stable from then on. Pictures are coming once I can get Mathematica to make an animated gif (hopefully without freezing my computer). EDIT: Can you give me the RGB values for your planets, so that we use the same conventions? EDIT 2: Now that I got the times right, it doesn't seem so inconsistent. I'll run the simulation some more.

This is going to sound silly, but if you just want to shift the planets around, how about doing it by hand (or in the code, or in the cfg this class should be turned into ), namely adding 2pi/Period * ÃŽâ€t to the meanAnomalyAtEpoch of each body. Now that the anomalies work as intended, using them sounds safer than tweaking the numerous inconsistent properties of the orbit class... Mattasmack: I think I'm going to give up on getting a symplectic integrator to work... How high does the relative error of your Hamiltonian go?

That leaves me some time to find the bugs in my own code; for the moment, my simulation seems to be quite keen on shooting every planet and moon on a straight line out of its orbit...

Documentation? There's this by Anatid, but it's very incomplete (and probably outdated). The game seems to handle angles in degrees, but the mean anomaly is not an angle, so it keeps it in radians... Sense cannot be made from this. Why can't it just use radians for everything? Thanks!

This is not a very good fix, because the bodies still end up at random places on their orbits (meaning you can't really easily set up a resonance or just move planets around their orbit by tweaking the anomaly). This is a good fix (stolen from Real Solar System): // // // Three lines of context cb2.hillSphere = GetNewHillSphere(cb2); cb2.orbit.period = GetNewPeriod(cb2); cb2.timeWarpAltitudeLimits = newWarpLimits; // <<< Line 864 // // // Insert fix: // NathanKello Gratias. This comes from anomFix in RSS. cb2.orbit.meanAnomaly = cb2.orbit.meanAnomalyAtEpoch; // let KSP handle epoch cb2.orbit.orbitPercent = cb2.orbit.meanAnomalyAtEpoch / 6.2831853071795862; cb2.orbit.ObTAtEpoch = cb2.orbit.orbitPercent * cb2.orbit.period; Now the bodies are where they should be, and therefore the spacecraft doesn't spawn in interplanetary space. You can (and you probably should) keep "cb_sun.OrbitingBodies.Remove(cb_kerbin)". It seems the orbit class is a complete mess, and as a result doesn't update all its orbital parameters to match what you give it. You might want to file a bug. I'll try running a simulation of the system I get from this fix using Mathematica's symplectic integrators. EDIT: Okay, this messes up Gilly and Ike, as you move them by tweaking the epoch. May I suggest moving them by changing the meanAnomalyAtEpoch instead? This would make things more consistent anyway. If my calculations are correct, setting M0=2.87273 for Ike and M0=6.15089 for Gilly takes them to where the epoch shift should put them.

I was trying to do this... ... and I came to an interesting conclusion about that. It's not the ship that decides to suddenly exist in solar orbit instead of on the pad, it's the pad (and pretty much all the bodies) that decide to exist somewhere else. If you try hard enough, the ship too starts existing in the wrong place, so it ends up on kerbin. More precisely: I'll call the orbital elements (e,a,i,Ω,É,ν), the last one being the true anomaly. I will call the mean anomaly at epoch Mt, and the mean anomaly M. The first five work fine, I get the same orbits as the ones displayed in-game. The anomalies are completely broken though. For instance, Moho has Mt=3.14, so it should be at its aphelion when the game starts. It isn't there. Jool has Mt=0.1, so it should be near its perihelion. It ends up somewhere else. However, when the ship starts existing in solar orbit, it ends up in Jool's orbit, near Jool's perihelion. I suspect it actually ends up where the pad should be. I decided to modify your code, adding the following trace after line 864 in PlanetShifter.cs (that's a bit of a big line number by the way, some of the things done in this class could be read from a cfg...): print("ALTERNIS KERBOL TRACE: " + cb2.gameObject.name); print("Mean Anomaly: " + cb2.orbit.meanAnomaly); print("True Anomaly: " + cb2.orbit.trueAnomaly); print("Semi-Major Axis: " + cb2.orbit.semiMajorAxis); print("Eccentricity: " + cb2.orbit.eccentricity); print("Argument of Periapsis: " + cb2.orbit.argumentOfPeriapsis); print("Inclination: " + cb2.orbit.inclination); print("Longitude of Ascending Node: " + cb2.orbit.LAN); print("Epoch: " + cb2.orbit.epoch); print("Mean Anomaly at Epoch: " + cb2.orbit.meanAnomalyAtEpoch); print("Eccentric Anomaly: " + cb2.orbit.eccentricAnomaly); This is what I get when the game first loads: [LOG 17:23:50.123] ALTERNIS KERBOL TRACE: Kerbin [LOG 17:23:50.124] Mean Anomaly: 3.14000014586568 [LOG 17:23:50.124] True Anomaly: 179.912318783786 [LOG 17:23:50.125] Semi-Major Axis: 68506000 [LOG 17:23:50.126] Eccentricity: 0.02 [LOG 17:23:50.126] Argument of Periapsis: 0 [LOG 17:23:50.127] Inclination: 0.4 [LOG 17:23:50.127] Longitude of Ascending Node: 0 [LOG 17:23:50.128] Epoch: 0 [LOG 17:23:50.129] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:50.129] Eccentric Anomaly: 3.1400313714949 [LOG 17:23:50.130] ALTERNIS KERBOL TRACE: Mun [LOG 17:23:50.131] Mean Anomaly: 1.70000276015492 [LOG 17:23:50.132] True Anomaly: 97.630183427476 [LOG 17:23:50.132] Semi-Major Axis: 43152000 [LOG 17:23:50.133] Eccentricity: 0.002 [LOG 17:23:50.133] Argument of Periapsis: 0 [LOG 17:23:50.134] Inclination: 0.109 [LOG 17:23:50.135] Longitude of Ascending Node: 180 [LOG 17:23:50.135] Epoch: 0 [LOG 17:23:50.136] Mean Anomaly at Epoch: 1.70000004768372 [LOG 17:23:50.137] Eccentric Anomaly: 1.70198557420591 [LOG 17:23:50.137] ALTERNIS KERBOL TRACE: Minmus [LOG 17:23:50.138] Mean Anomaly: 0.900000326095427 [LOG 17:23:50.139] True Anomaly: 51.5662208475882 [LOG 17:23:50.139] Semi-Major Axis: 14740300 [LOG 17:23:50.140] Eccentricity: 0 [LOG 17:23:50.140] Argument of Periapsis: 38 [LOG 17:23:50.141] Inclination: 0.03 [LOG 17:23:50.142] Longitude of Ascending Node: 78 [LOG 17:23:50.142] Epoch: 0 [LOG 17:23:50.143] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:50.143] Eccentric Anomaly: 0.900000326095427 [LOG 17:23:50.144] ALTERNIS KERBOL TRACE: Moho [LOG 17:23:50.145] Mean Anomaly: 3.14000027504539 [LOG 17:23:50.145] True Anomaly: 179.95733898431 [LOG 17:23:50.146] Semi-Major Axis: 4275040399 [LOG 17:23:50.147] Eccentricity: 0.4 [LOG 17:23:50.147] Argument of Periapsis: 15 [LOG 17:23:50.148] Inclination: 0.2502 [LOG 17:23:50.148] Longitude of Ascending Node: 70 [LOG 17:23:50.149] Epoch: 0 [LOG 17:23:50.150] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:50.150] Eccentric Anomaly: 3.14045524027372 [LOG 17:23:50.151] ALTERNIS KERBOL TRACE: Eve [LOG 17:23:50.152] Mean Anomaly: 3.14000017153398 [LOG 17:23:50.152] True Anomaly: 179.910205018822 [LOG 17:23:50.153] Semi-Major Axis: 8185550300 [LOG 17:23:50.154] Eccentricity: 0.008 [LOG 17:23:50.154] Argument of Periapsis: 0 [LOG 17:23:50.155] Inclination: 1.02 [LOG 17:23:50.155] Longitude of Ascending Node: 15 [LOG 17:23:50.156] Epoch: 0 [LOG 17:23:50.157] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:50.157] Eccentric Anomaly: 3.14001281027524 [LOG 17:23:50.158] ALTERNIS KERBOL TRACE: Duna [LOG 17:23:50.159] Mean Anomaly: 3.14000012667618 [LOG 17:23:50.159] True Anomaly: 179.917343645244 [LOG 17:23:50.160] Semi-Major Axis: 34598850 [LOG 17:23:50.161] Eccentricity: 0.05 [LOG 17:23:50.161] Argument of Periapsis: 0 [LOG 17:23:50.162] Inclination: 0.7 [LOG 17:23:50.162] Longitude of Ascending Node: 135.5 [LOG 17:23:50.163] Epoch: 0 [LOG 17:23:50.164] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:50.164] Eccentric Anomaly: 3.14007596126343 [LOG 17:23:50.165] ALTERNIS KERBOL TRACE: Ike [LOG 17:23:50.166] Mean Anomaly: 4.97155489782577 [LOG 17:23:50.167] True Anomaly: 189.260954621812 [LOG 17:23:50.167] Semi-Major Axis: 167988084550 [LOG 17:23:50.168] Eccentricity: 0.9585 [LOG 17:23:50.169] Argument of Periapsis: 0 [LOG 17:23:50.169] Inclination: 28.45 [LOG 17:23:50.170] Longitude of Ascending Node: 0 [LOG 17:23:50.170] Epoch: 325000000 [LOG 17:23:50.171] Mean Anomaly at Epoch: 1.70000004768372 [LOG 17:23:50.172] Eccentric Anomaly: 4.15708094532696 [LOG 17:23:50.172] ALTERNIS KERBOL TRACE: Jool [LOG 17:23:50.173] Mean Anomaly: 0.100000005092122 [LOG 17:23:50.174] True Anomaly: 5.92825622352348 [LOG 17:23:50.174] Semi-Major Axis: 13605008470 [LOG 17:23:50.175] Eccentricity: 0.017 [LOG 17:23:50.175] Argument of Periapsis: 0 [LOG 17:23:50.176] Inclination: 1.957 [LOG 17:23:50.177] Longitude of Ascending Node: 0 [LOG 17:23:50.177] Epoch: 0 [LOG 17:23:50.178] Mean Anomaly at Epoch: 0.100000001490116 [LOG 17:23:50.179] Eccentric Anomaly: 0.101726372341934 [LOG 17:23:50.179] ALTERNIS KERBOL TRACE: Laythe [LOG 17:23:50.180] Mean Anomaly: 3.14000722051126 [LOG 17:23:50.181] True Anomaly: 179.909163475946 [LOG 17:23:50.181] Semi-Major Axis: 27184000 [LOG 17:23:50.182] Eccentricity: 0 [LOG 17:23:50.182] Argument of Periapsis: 0 [LOG 17:23:50.183] Inclination: 0 [LOG 17:23:50.184] Longitude of Ascending Node: 180 [LOG 17:23:50.184] Epoch: 0 [LOG 17:23:50.185] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:50.185] Eccentric Anomaly: 3.14000722051126 [LOG 17:23:50.186] ALTERNIS KERBOL TRACE: Vall [LOG 17:23:50.187] Mean Anomaly: 0.900003533950579 [LOG 17:23:50.187] True Anomaly: 52.5622555191047 [LOG 17:23:50.188] Semi-Major Axis: 4995040 [LOG 17:23:50.189] Eccentricity: 0.011 [LOG 17:23:50.189] Argument of Periapsis: 0 [LOG 17:23:50.190] Inclination: 2.337 [LOG 17:23:50.190] Longitude of Ascending Node: 0 [LOG 17:23:50.191] Epoch: 0 [LOG 17:23:50.192] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:50.192] Eccentric Anomaly: 0.908679150188512 [LOG 17:23:50.193] ALTERNIS KERBOL TRACE: Bop [LOG 17:23:50.194] Mean Anomaly: 0.900000668510714 [LOG 17:23:50.194] True Anomaly: 60.2170563373709 [LOG 17:23:50.195] Semi-Major Axis: 128500000 [LOG 17:23:50.196] Eccentricity: 0.09 [LOG 17:23:50.196] Argument of Periapsis: 25 [LOG 17:23:50.197] Inclination: 0.894 [LOG 17:23:50.197] Longitude of Ascending Node: 10 [LOG 17:23:50.198] Epoch: 0 [LOG 17:23:50.199] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:50.199] Eccentric Anomaly: 0.974466903770252 [LOG 17:23:50.200] ALTERNIS KERBOL TRACE: Tylo [LOG 17:23:50.201] Mean Anomaly: 3.14000188378209 [LOG 17:23:50.201] True Anomaly: 179.914128432408 [LOG 17:23:50.202] Semi-Major Axis: 24708887045 [LOG 17:23:50.203] Eccentricity: 0.03 [LOG 17:23:50.203] Argument of Periapsis: 0 [LOG 17:23:50.204] Inclination: 1.22 [LOG 17:23:50.204] Longitude of Ascending Node: 0 [LOG 17:23:50.205] Epoch: 0 [LOG 17:23:50.206] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:50.206] Eccentric Anomaly: 3.1400482168654 [LOG 17:23:50.207] ALTERNIS KERBOL TRACE: Gilly [LOG 17:23:50.208] Mean Anomaly: 4.41517458953723 [LOG 17:23:50.208] True Anomaly: 184.881751093799 [LOG 17:23:50.209] Semi-Major Axis: 34084734575 [LOG 17:23:50.210] Eccentricity: 0.970504 [LOG 17:23:50.210] Argument of Periapsis: 79.08 [LOG 17:23:50.211] Inclination: 225.05 [LOG 17:23:50.211] Longitude of Ascending Node: 25.3 [LOG 17:23:50.212] Epoch: 6000000 [LOG 17:23:50.213] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:50.213] Eccentric Anomaly: 3.81211098805513 [LOG 17:23:50.214] ALTERNIS KERBOL TRACE: Pol [LOG 17:23:50.215] Mean Anomaly: 0.900000394153509 [LOG 17:23:50.215] True Anomaly: 59.5029457206509 [LOG 17:23:50.216] Semi-Major Axis: 179890000 [LOG 17:23:50.217] Eccentricity: 0.083 [LOG 17:23:50.217] Argument of Periapsis: 15 [LOG 17:23:50.218] Inclination: 4.25 [LOG 17:23:50.218] Longitude of Ascending Node: 120 [LOG 17:23:50.219] Epoch: 0 [LOG 17:23:50.220] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:50.220] Eccentric Anomaly: 0.96839029243542 [LOG 17:23:50.221] ALTERNIS KERBOL TRACE: Dres [LOG 17:23:50.222] Mean Anomaly: 3.14000011277569 [LOG 17:23:50.222] True Anomaly: 179.909120305738 [LOG 17:23:50.223] Semi-Major Axis: 17580043 [LOG 17:23:50.224] Eccentricity: 0.002 [LOG 17:23:50.224] Argument of Periapsis: 90 [LOG 17:23:50.225] Inclination: 0.109 [LOG 17:23:50.225] Longitude of Ascending Node: 280 [LOG 17:23:50.226] Epoch: 0 [LOG 17:23:50.227] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:50.227] Eccentric Anomaly: 3.14000329149853 [LOG 17:23:50.228] ALTERNIS KERBOL TRACE: Eeloo [LOG 17:23:50.229] Mean Anomaly: 3.14000010730551 [LOG 17:23:50.229] True Anomaly: 179.922023937306 [LOG 17:23:50.230] Semi-Major Axis: 90118820000 [LOG 17:23:50.231] Eccentricity: 0.08 [LOG 17:23:50.231] Argument of Periapsis: 260 [LOG 17:23:50.232] Inclination: 1.15 [LOG 17:23:50.232] Longitude of Ascending Node: 50 [LOG 17:23:50.233] Epoch: 0 [LOG 17:23:50.234] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:50.234] Eccentric Anomaly: 3.14011807365735 After lauching a vessel which ends up in solar orbit, reverting to the VAB and relaunching (now I'm on the pad): [LOG 17:23:52.500] ALTERNIS KERBOL TRACE: Kerbin [LOG 17:23:52.501] Mean Anomaly: 5.24873697767145 [LOG 17:23:52.501] True Anomaly: 298.735391205793 [LOG 17:23:52.502] Semi-Major Axis: 68506000 [LOG 17:23:52.503] Eccentricity: 0.02 [LOG 17:23:52.503] Argument of Periapsis: 0 [LOG 17:23:52.504] Inclination: 0.4 [LOG 17:23:52.504] Longitude of Ascending Node: 0 [LOG 17:23:52.505] Epoch: 0 [LOG 17:23:52.506] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:52.506] Eccentric Anomaly: 5.23137048164601 [LOG 17:23:52.507] ALTERNIS KERBOL TRACE: Mun [LOG 17:23:52.508] Mean Anomaly: 2.23037310431032 [LOG 17:23:52.508] True Anomaly: 127.971802097603 [LOG 17:23:52.509] Semi-Major Axis: 43152000 [LOG 17:23:52.510] Eccentricity: 0.002 [LOG 17:23:52.510] Argument of Periapsis: 0 [LOG 17:23:52.511] Inclination: 0.109 [LOG 17:23:52.512] Longitude of Ascending Node: 180 [LOG 17:23:52.512] Epoch: 0 [LOG 17:23:52.513] Mean Anomaly at Epoch: 1.70000004768372 [LOG 17:23:52.513] Eccentric Anomaly: 2.23195167099713 [LOG 17:23:52.514] ALTERNIS KERBOL TRACE: Minmus [LOG 17:23:52.515] Mean Anomaly: 1.85036737861459 [LOG 17:23:52.515] True Anomaly: 106.018242580832 [LOG 17:23:52.516] Semi-Major Axis: 14740300 [LOG 17:23:52.517] Eccentricity: 0 [LOG 17:23:52.517] Argument of Periapsis: 38 [LOG 17:23:52.518] Inclination: 0.03 [LOG 17:23:52.518] Longitude of Ascending Node: 78 [LOG 17:23:52.519] Epoch: 0 [LOG 17:23:52.520] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:52.520] Eccentric Anomaly: 1.85036737861459 [LOG 17:23:52.521] ALTERNIS KERBOL TRACE: Moho [LOG 17:23:52.522] Mean Anomaly: 4.28930132205398 [LOG 17:23:52.522] True Anomaly: 212.91546205275 [LOG 17:23:52.523] Semi-Major Axis: 4275040399 [LOG 17:23:52.524] Eccentricity: 0.4 [LOG 17:23:52.524] Argument of Periapsis: 15 [LOG 17:23:52.525] Inclination: 0.2502 [LOG 17:23:52.525] Longitude of Ascending Node: 70 [LOG 17:23:52.526] Epoch: 0 [LOG 17:23:52.527] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:52.527] Eccentric Anomaly: 3.98937527206724 [LOG 17:23:52.528] ALTERNIS KERBOL TRACE: Eve [LOG 17:23:52.529] Mean Anomaly: 4.13397191968825 [LOG 17:23:52.529] True Anomaly: 236.095736768881 [LOG 17:23:52.530] Semi-Major Axis: 8185550300 [LOG 17:23:52.530] Eccentricity: 0.008 [LOG 17:23:52.531] Argument of Periapsis: 0 [LOG 17:23:52.532] Inclination: 1.02 [LOG 17:23:52.532] Longitude of Ascending Node: 15 [LOG 17:23:52.533] Epoch: 0 [LOG 17:23:52.533] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:52.534] Eccentric Anomaly: 4.12730260459927 [LOG 17:23:52.535] ALTERNIS KERBOL TRACE: Duna [LOG 17:23:52.536] Mean Anomaly: 6.06957993837549 [LOG 17:23:52.536] True Anomaly: 346.468056629552 [LOG 17:23:52.537] Semi-Major Axis: 34598850 [LOG 17:23:52.538] Eccentricity: 0.05 [LOG 17:23:52.538] Argument of Periapsis: 0 [LOG 17:23:52.539] Inclination: 0.7 [LOG 17:23:52.539] Longitude of Ascending Node: 135.5 [LOG 17:23:52.540] Epoch: 0 [LOG 17:23:52.541] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:52.541] Eccentric Anomaly: 6.05843688232 [LOG 17:23:52.542] ALTERNIS KERBOL TRACE: Ike [LOG 17:23:52.543] Mean Anomaly: 1.17263800967908 [LOG 17:23:52.543] True Anomaly: 169.682365446553 [LOG 17:23:52.544] Semi-Major Axis: 167988084550 [LOG 17:23:52.545] Eccentricity: 0.9585 [LOG 17:23:52.545] Argument of Periapsis: 0 [LOG 17:23:52.546] Inclination: 28.45 [LOG 17:23:52.546] Longitude of Ascending Node: 0 [LOG 17:23:52.547] Epoch: 325000000 [LOG 17:23:52.548] Mean Anomaly at Epoch: 1.70000004768372 [LOG 17:23:52.548] Eccentric Anomaly: 2.03129291313392 [LOG 17:23:52.549] ALTERNIS KERBOL TRACE: Jool [LOG 17:23:52.550] Mean Anomaly: 1.13667519953759 [LOG 17:23:52.550] True Anomaly: 66.9096924646006 [LOG 17:23:52.551] Semi-Major Axis: 13605008470 [LOG 17:23:52.552] Eccentricity: 0.017 [LOG 17:23:52.552] Argument of Periapsis: 0 [LOG 17:23:52.553] Inclination: 1.957 [LOG 17:23:52.553] Longitude of Ascending Node: 0 [LOG 17:23:52.554] Epoch: 0 [LOG 17:23:52.555] Mean Anomaly at Epoch: 0.100000001490116 [LOG 17:23:52.555] Eccentric Anomaly: 1.15220747806286 [LOG 17:23:52.556] ALTERNIS KERBOL TRACE: Laythe [LOG 17:23:52.557] Mean Anomaly: 3.15089116032308 [LOG 17:23:52.557] True Anomaly: 180.532767298915 [LOG 17:23:52.558] Semi-Major Axis: 27184000 [LOG 17:23:52.559] Eccentricity: 0 [LOG 17:23:52.559] Argument of Periapsis: 0 [LOG 17:23:52.560] Inclination: 0 [LOG 17:23:52.560] Longitude of Ascending Node: 180 [LOG 17:23:52.561] Epoch: 0 [LOG 17:23:52.561] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:52.562] Eccentric Anomaly: 3.15089116032308 [LOG 17:23:52.563] ALTERNIS KERBOL TRACE: Vall [LOG 17:23:52.564] Mean Anomaly: 0.389216407145809 [LOG 17:23:52.564] True Anomaly: 22.7849285654848 [LOG 17:23:52.565] Semi-Major Axis: 4995040 [LOG 17:23:52.565] Eccentricity: 0.011 [LOG 17:23:52.566] Argument of Periapsis: 0 [LOG 17:23:52.567] Inclination: 2.337 [LOG 17:23:52.567] Longitude of Ascending Node: 0 [LOG 17:23:52.568] Epoch: 0 [LOG 17:23:52.568] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:52.569] Eccentric Anomaly: 0.393433386264814 [LOG 17:23:52.570] ALTERNIS KERBOL TRACE: Bop [LOG 17:23:52.570] Mean Anomaly: 0.900004629442292 [LOG 17:23:52.571] True Anomaly: 60.2173070665353 [LOG 17:23:52.572] Semi-Major Axis: 128500000 [LOG 17:23:52.572] Eccentricity: 0.09 [LOG 17:23:52.573] Argument of Periapsis: 25 [LOG 17:23:52.574] Inclination: 0.894 [LOG 17:23:52.574] Longitude of Ascending Node: 10 [LOG 17:23:52.575] Epoch: 0 [LOG 17:23:52.575] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:52.576] Eccentric Anomaly: 0.974471075563775 [LOG 17:23:52.577] ALTERNIS KERBOL TRACE: Tylo [LOG 17:23:52.577] Mean Anomaly: 0.0295249802583349 [LOG 17:23:52.578] True Anomaly: 1.79708705770096 [LOG 17:23:52.579] Semi-Major Axis: 24708887045 [LOG 17:23:52.579] Eccentricity: 0.03 [LOG 17:23:52.580] Argument of Periapsis: 0 [LOG 17:23:52.581] Inclination: 1.22 [LOG 17:23:52.581] Longitude of Ascending Node: 0 [LOG 17:23:52.582] Epoch: 0 [LOG 17:23:52.582] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:52.583] Eccentric Anomaly: 0.0304379786241376 [LOG 17:23:52.584] ALTERNIS KERBOL TRACE: Gilly [LOG 17:23:52.584] Mean Anomaly: 5.26038901729548 [LOG 17:23:52.585] True Anomaly: 189.677735432824 [LOG 17:23:52.586] Semi-Major Axis: 34084734575 [LOG 17:23:52.586] Eccentricity: 0.970504 [LOG 17:23:52.587] Argument of Periapsis: 79.08 [LOG 17:23:52.587] Inclination: 225.05 [LOG 17:23:52.588] Longitude of Ascending Node: 25.3 [LOG 17:23:52.589] Epoch: 6000000 [LOG 17:23:52.589] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:52.590] Eccentric Anomaly: 4.35217170920849 [LOG 17:23:52.591] ALTERNIS KERBOL TRACE: Pol [LOG 17:23:52.591] Mean Anomaly: 0.900001543653261 [LOG 17:23:52.592] True Anomaly: 59.5030179929597 [LOG 17:23:52.593] Semi-Major Axis: 179890000 [LOG 17:23:52.593] Eccentricity: 0.083 [LOG 17:23:52.594] Argument of Periapsis: 15 [LOG 17:23:52.595] Inclination: 4.25 [LOG 17:23:52.595] Longitude of Ascending Node: 120 [LOG 17:23:52.596] Epoch: 0 [LOG 17:23:52.596] Mean Anomaly at Epoch: 0.899999976158142 [LOG 17:23:52.597] Eccentric Anomaly: 0.968391498664067 [LOG 17:23:52.598] ALTERNIS KERBOL TRACE: Dres [LOG 17:23:52.598] Mean Anomaly: 4.44963358703825 [LOG 17:23:52.599] True Anomaly: 254.724054979369 [LOG 17:23:52.600] Semi-Major Axis: 17580043 [LOG 17:23:52.600] Eccentricity: 0.002 [LOG 17:23:52.601] Argument of Periapsis: 90 [LOG 17:23:52.601] Inclination: 0.109 [LOG 17:23:52.602] Longitude of Ascending Node: 280 [LOG 17:23:52.603] Epoch: 0 [LOG 17:23:52.603] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:52.604] Eccentric Anomaly: 4.44770323751809 [LOG 17:23:52.605] ALTERNIS KERBOL TRACE: Eeloo [LOG 17:23:52.605] Mean Anomaly: 3.1400021695025 [LOG 17:23:52.606] True Anomaly: 179.922124911674 [LOG 17:23:52.607] Semi-Major Axis: 90118820000 [LOG 17:23:52.607] Eccentricity: 0.08 [LOG 17:23:52.608] Argument of Periapsis: 260 [LOG 17:23:52.608] Inclination: 1.15 [LOG 17:23:52.609] Longitude of Ascending Node: 50 [LOG 17:23:52.610] Epoch: 0 [LOG 17:23:52.610] Mean Anomaly at Epoch: 3.14000010490417 [LOG 17:23:52.611] Eccentric Anomaly: 3.14011998309916 As you can see, the planets have been moved around. Mt and M are inconsistent however, so this may result in further issues. Back to Which mean anomalies should I use? If I use the ones inherited from stock, Jool will start at its perihelion, moho at its aphelion, and the Mun, Laythe, Jool and Kerbin Kerbin, Minmus, Jool and Laythe will lie in a straight line (in this order) at the start (hopefully this is the configuration you get in your bugfixed version). Otherwise, just start Alternis Kerbol 0.0 to see the initial configuration.

Thanks! You might want to add this snippet to the documentation, lest somebody else complain you can't rebind keys.

This is important. There are quite a few mods out there that hardcode keybindings (I'm looking at you, stretchytanks). This is annoying for people using custom keybindings / another keyboard layout (I use dvorak, so only A and M are bound to the same actions). While I can recompile the dll with the modified keybindings, this makes the installation rather tedious. EDIT: now that I think of it, this would still be a problem for those of us who use joysticks for the throttle; You never want the in-game throttle and the physical one to be in different states (otherwise moving the throttle starts the engine up again). I might want to try implementing custom action groups next year... We do. And they should be fully rebindable, as are the existing 10, to both keyboard input and joystick buttons... (looks at these USB adaptors for 30-switch panels they sell for desktop flight simulators) They could be persisted in the command pod, and the active action groups could then be those of the controlling command pod... Controlling from a docking port may lead to trouble though...

At https://drive.google.com/folderview?id=0B4y-shYXMH9BcEhsUWNyLXpXZEU&usp=sharing. If you just want the models and textures, they are under Models only. If you want the modified resources file (with Hydrogen) and the cfgs for the Bacon cell and Electrolyser (beware, my electrolyser is less efficient than Taranis's, which violates the conservation of energy), grab the ThunderAerospace folder and merge it with the one under GameData. For convenience I have added a zipped version of that folder. You will need to make a Hydrogen tank yourself if you want to be able to use the fuel cell. I might model some tanks next year, I also want to model the Sabatier and the Bosch reactors.

I can replicate that, investigating... Edit: Found and fixed. I had grabbed an old version of the cfg from my 0.22 install instead of the new version from the 0.23 install. For some reason I had picked the right cfg for the fuel cell.

Thanks, this is my first attempt at modeling/texturing, so there is a lot of room for improvement. You will need to do some cfg editing in order for the parts to reference the right model though. Moreover, there is no fuel cell in the current version of TAC. Finally, there is no Hydrogen resource in TAC. I just added my cfgs for the Fuel Cell and Electrolyser, as well as a modified TacResources.cfg that includes Hydrogen, in a ThunderAerospace folder that you can just paste in your GameData install. There are no H2 tanks at the moment though, so you will probably want to make one yourself (by cfg editing an existing TAC tank or something similar). The cfgs being derivatives of Taranis's work, they are CC-BY-NC-SA. The models and textures remain CC-BY-SA. Bear in mind that my Electrolyser is far less powerful than Taranis's Water Splitter (which violates the conservation of energy, see this bug). It is also a 1.25m part, and it consume 1 Water per day, producing 3.7215675 Oxygen per day. The Bacon cell produces 3 Water per day (from 3.7215675 Oxygen and 7.443135 Hydrogen), and produces 624 W (0.624 ElectricCharge/s). The sources for these numbers can be found on page 33 of this thread. Might as well give the link again: https://drive.google.com/folderview?id=0B4y-shYXMH9BcEhsUWNyLXpXZEU&usp=drive_web The problem of the covers was discussed on the Realism Overhaul thread. It certainly looks awkward if you launch with them exposed; I typically hide them under fairings during the ascent.

They are, and this is coming from a student in mathematics.

Done. Hydrogen RAL 3000 and Oxygen is RAL 9010 as per CEN EN 1089-3. Also added a bump map and cleaner connexions between the pipes and tanks.

Could the attachment nodes perhaps be moved in proportion then? Something like node_stack_top = 0.0, 0.0920, 0.0, 0.0, -1.0, 0.0, 0 node_stack_bottom = 0.0, -0.0920, 0.0, 0.0, -1.0, 0.0, 0 I understand actually remodeling the parachutes to be taller would be quite tedious, but the flickering caused by the clipping (e.g. when stacking Mk I pod - stack mains - stack drogues) is quite ugly. The Mk I pod merges well with these parachutes without having the attachment nodes inside the model. Screenshots: Good point. Would node_stack_top = 0.0, 0.1534, 0.0, 0.0, -1.0, 0.0, 0 node_stack_bottom = 0.0, -0.1304, 0.0, 0.0, -1.0, 0.0, 0 be an acceptable solution? This allows for good merging between the parachute and the pod, and nearly no clipping when stacking stack parachutes. Thanks! In the same vein, albeit possibly harder to fix: activating the combo nosecone chute below the drogue cutoff altitude results in the main parachute being deployed through the cover, as this cover is jettisoned when the drogues deploy. I think two single canopies are the way to go. I don't know of any spacecraft that landed/splashed down on six parachutes. This is a direct result of the 'forced orientation' thing: the pod does hang from the bottom of the parachute line, it's just that the parachute line is kept at an angle from the vertical. This is probably better than clipping parachutes, I simply wanted to bring it to your attention. Screenshots to clarify my confusing explanations: This is would indeed explain why it doesn't . This is true (unless you are, like me, too lazy to update from VS2008 and don't have System.Threading. Time to find the VS2012 installer).

Hi, I would like to report a few bugs: 1. The small stack chutes have their model distorted (they are too tall), and stacking two small stack chutes results in some unsightly clipping (the nodes are inside the model). Setting scale = 0.425, 0.425, 0.425 instead of scale = 0.425, 0.6, 0.425 in the relevant cfgs fixes this, with no obvious adverse effects. 2. stacking large stack chutes results in some unsightly clipping (same as above, but the model is not distorted). Setting node_stack_top = 0.0, 0.1534, 0.0, 0.0, -1.0, 0.0, 0 node_stack_bottom = 0.0, -0.1534, 0.0, 0.0, -1.0, 0.0, 0 node_attach = 0.0, -0.1534, 0.0, 0.0, 1.0, 0.0 instead of the current +/- 0.1304 fixes this with no obvious adverse effects. 3. The parachute covers on both small and large stack chutes are swapped: pre-deploying the main parachute jettisons the 2nd cover, and pre-deploying the 2nd parachute jettisons the main cover. 4. While the small main stack parachutes are fine, the large main stack parachutes still clip (having dual triple parachutes looks very weird anyway, perhaps this part could use single canopies instead of triple ones). 5. When cutting one of the parachutes on a stack parachute, the parachute line will remain at an angle to the vertical. 6. Changing the diameter has no effect on the diameter of the parachute model. This is probably intended/known, but then you mentioned this feature in this post (I like the idea by the way. I don't think square rooting the value would make much sense though (m^(1/2) ?)). 7. I think the System.Threading.Tasks namespace is unused in RealChuteModule.cs. I would have filed them on github, but then the relevant configs for bugs 1 through 4 are not up to date.

You mean using CEN EN 1089-3? I can do that (I was not quite fond of pipe markings on tanks anyway). Which parts of the tank should I colour? (Finding the shoulder of a shpere is hard.) I can make the psd s and blend s available, but then I keep tweaking things and moving the UV mapping around. My layers are very messy too (I often find myself drawing on the wrong one). Edited to add: CEN EN 1089-3 is a standard for transportable cylinders. Should I also include transport GHS pictograms?