[WIP][1.8.1, 1.9.1, 1.10.1, 1.11.0–2, 1.12.2–5] Principia—releases every new moon—n-Body and Extended Body Gravitation

[TranquilTempest]

Also, Is there a way to visualize gravitational field lines? I'm trying to set up a horseshoe orbit. 

[hypervelocity]

hi guys - quick question for all you knowledgeable guys!

would there be a way of implementing a full autopilot suite as MechJeb for principia? It deffinitely is waaay out of my league to design & produce such a thing, but I have a modder friend who might be up to the task, and I would like to pitch the idea to him.

I would like to know if it'd be feasible before getting him to investigate on the matter.

cheers!

[eggrobin]

For the new moon (lunation number 219), the new release (Cesàro) is out.

The histories of the vessels are now computed in parallel, speeding up high timewarp on multi-core processors.

A bug was fixed that caused a crash when crashing two vessels into each other.

Again, we support two versions of KSP: downloads are available for 1.3 and for 1.2.2. Make sure you download the right one (if you don't, the game will crash on load).

See the change log for details.

[pleroy]

5 hours ago, hypervelocity said:

would there be a way of implementing a full autopilot suite as MechJeb for principia? It deffinitely is waaay out of my league to design & produce such a thing, but I have a modder friend who might be up to the task, and I would like to pitch the idea to him.

I would like to know if it'd be feasible before getting him to investigate on the matter.

That would be a lot of work.

Such a mod would have to use the Principia APIs directly.  This would be a nightmare because our APIs are quite complex and not-very-well documented, and we change them all the time; we are just not prepared to provide documented and stable APIs to the outside world; also, the autopilot mod would have to be written in C++.

To put things in perspective, Principia has about 75,000 lines of hand-crafted C++ and another 25,000 lines of automatically generated C++.  Understanding how it all works is not for the faint of heart.

[hypervelocity]

gotcha, @pleroy!!! many thanks for the prompt response, and also the details you shared are very much appreciated! I take the opportunity to congratulate you & the devs again for this beautiful piece of work you have brought forward to all of us!!! eternally grateful! you take the KSP experience to a whole new level!!! <3

[Guest]

I just started using Principia interplanetary today. When planning a maneuver for transfer to Mars I found it more intuitive, perhaps because of literally years of using a patched conics system, to have the planning frame be Earth-centric with the reference plane being Mars-centric, allowing me to see the projected Mars periapsis while adjusting the burn in a "patched conics" reference. Is there anything inherently wrong with this approach?

[Nittany Tiger]

I do wish Principa worked with Hyperedit, but I'm glad it works somewhat with the stock orbit editor.  I need the ability to place objects in LEO in any inclination and LAN.

I haven't confirmed this yet, but I suspect KSP's patched conics doesn't do momentum transfer during planetary flybys.  In other words, if you fly by a planet, your entry and exit speed out of an SOI is the same if you don't accelerate.  The only thing that changes is direction.  In real flybys, you actually gain velocity from the planet's forward motion.  I'm hoping Principia's gravity model does capture momentum transfers.

[UmbralRaptor]

2 hours ago, Nittany Tiger said:

I haven't confirmed this yet, but I suspect KSP's patched conics doesn't do momentum transfer during planetary flybys.  In other words, if you fly by a planet, your entry and exit speed out of an SOI is the same if you don't accelerate.  The only thing that changes is direction.  In real flybys, you actually gain velocity from the planet's forward motion.  I'm hoping Principia's gravity model does capture momentum transfers.

Stock KSP's planets are on rails, so no actual momentum exchange is possible, though you can get some weirdness from exiting at  the same speed but different distance from the star (or planet for a moon flyby). You can also do strange things to momentum&energy by transferring propellant in some cases.

Relatedly, Principia's planets are unaffected by the gravitational pull of your craft. Such a violation of conservation laws is rather difficult to spot, though, and the planet and star pulling on the craft part should act just like real life. (If with the planet not marginally changed in speed).

[Iskierka]

Or to clarify, it would not be possible to have meaningful momentum exchange even with celestial bodies not being on rails; even the largest Kerbal rockets are completely dominated in mass by the smallest bodies. This means that, even locking momentum of the body, so there is no exchange, there is negligible, or likely nonexistent difference with the fully simulated case, given computation precision limits. Do note that while there isn't momentum exchange, there is momentum change for the satellite; we can violate conservation here with no real consequences for the accuracy of the simulation, as the change would be eaten by double precision anyway.

 

Scott Manley explains how gravity assists actually work, even without there being meaningful momentum exchange, and even in patched conics of stock KSP: How Gravity Assists Work

[Nittany Tiger]

I'm aware how gravity assist work in stock.  I see them as gravitational bodies changing the direction of a velocity vector but not the magnitude.  I'll still watch the video again to be sure.

I just need proper momentum transfer for an opposition class Mars mission via the Voyage novel.  I know you can do the mission with patched conics, but you have to fly by Venus on the opposite side to get the velocity vector change needed to reach Mars.  With momentum transfer, you can fly by the dark side and get a Mars-bound trajectory that's shorter, and a dark side flyby of Venus is what happens in Voyage.

I do want to test and see if craft velocities obey the math in this link: http://www.mathpages.com/home/kmath114/kmath114.htm

 

[Iskierka]

The magnitude does not change appreciably under any physical model. This is the point of conservation of momentum. In fact, neglecting the body's part of momentum exchange increases the desired velocity change in the solar reference frame, as it would, insofar as is meaningful, move the body in the opposite direction to what you desire, while your receding velocity will not be changed, thus being pulled back with the planet as its velocity change subtracts from yours.

If the trajectory described that you wish to execute is possible at all, it is possible in Principia, despite having only momentum change, not exchange. If the trajectory does not make use of low-energy transfers and other unstable regions of n-body physics, it is 99% likely to be possible in stock KSP. Even if it does make use of such conditions where the approximations of patched conics are made bare, it can likely be approximated in stock, given it has sufficient energy to reach Mars to begin with, it will not be spending humongous amounts of time in these regions.

[Nittany Tiger]

I meant under conservation of momentum.  I'm aware of the laws of physics, and I'm also aware gravitational fields are conservative, so in the body frame of reference, v_in = v_out (because no net work is done on the craft), or the speed you enter the SOI in is the speed you leave with.  I know in stock, what matters more in flybys is the direction in 3D space and periapsis at flyby.

It could be possible that the flight plan in Voyage is wrong, because my first instinct was that if you flew by Venus on the dark side, you should exit with an orbit going closer to the sun, not farther.  You'd need to fly by the light side of Venus to get the boost to Mars.  Flying by the dark side of Venus, getting a 30-degree velocity vector change that would result in an inward-bound orbit, and then going to Mars just didn't make sense without Venus giving some sort of acceleration to the small craft during flyby.  Might just need to do some experiments with KSP RSS, both with Principia and stock patched conics, and do some research to see how Venus flybys are used in real missions.  I think Galileo and Cassini used Venus flybys to get to the outer planets.

Edited October 3, 2017 by Nittany Tiger

[Pand5461]

1 hour ago, Nittany Tiger said:

It could be possible that the flight plan in Voyage is wrong, because my first instinct was that if you flew by Venus on the dark side, you should exit with an orbit going closer to the sun, not farther.

Does not look wrong to me. Look at the Cassini mission plan: both Venus flybys are on the dark side.

EDIT: It's unclear about the first one, the second one is clearly on the dark side.

Edited October 3, 2017 by Pand5461

[Nittany Tiger]

10 hours ago, Pand5461 said:

Does not look wrong to me. Look at the Cassini mission plan: both Venus flybys are on the dark side.

I know.  Many missions going to the outer planets do dark-side flybys of planets like Earth and Venus.

My point is that this is what a dark-side Venus flyby looks like in stock patched conics.

Leave Earth, swing by Venus on the dark side, and you somehow end up dipping below Mercury's orbit.

What it's supposed to look like is:

That's the plan given on the first pages of the book (in my copy).  Apologies for the bad quality of this pic.  Only photocopy I could find (Unless I photocopy the one from my copy).  I think you can at least see that the Venus flyby leads to a Mars intercept.  If you're curious about the dates, Earth departure is March 22nd, 1985; Venus flyby is September 8th, 1985; and Mars arrival is March 25th, 1986.

When I actually looked this problem, I did an experiment with where I placed a maneuver node just outside the Venus SOI at ship departure and played with it until I got a Mars encounter.

So Venus does give Ares a substantial velocity boost on flyby.  Furthermore, without the boost, in stock patched conics, the arrival date at Mars is always in July.  With the correction above, the arrival date at Mars is March 22nd, 1986.  That's why I concluded KSP's patched conics is missing something with planet-craft interactions during flybys.  Planets don't give craft the proper velocity kick.  They just change the direction of flight.  In real life, planets must somehow give spacecraft a velocity kick when the spacecraft falls into the planet's SOI, and I feel it has to do with the planet's orbital velocity around the sun.  That's what my research tells me.  I called it momentum transfer because I thought the planet was giving some of it's orbital momentum to the spacecraft (and the spacecraft is probably giving a very tiny tug on the planet).  It doesn't violate conservation of momentum because in the spacecraft-planet system, the total momentum of the system does not change.  It's akin to an elastic collision, but with planets and gravity fields, and one site equates flybys to elastic collisions to set up the conservation of momentum argument.

This was my whole point in saying stock patched conics is missing something with flybys, and what Prinicpia might provide.  Neither system has to give a momentum change to the planet because it's so small that it's negligible on time and space scales of this game.  Nonetheless, it seems significant to the spacecraft.

Hope this clarifies my understanding of flybys, but this is possibly off-topic of the thread.  My original question was will Principia allow me to do the opposition-class Mars mission as done in Voyage with a dark-side Venus fly-by and 30 degree velocity vector change boosting my craft to Mars and not Mercury?

[Iskierka]

12 hours ago, Pand5461 said:

Does not look wrong to me. Look at the Cassini mission plan: both Venus flybys are on the dark side.

EDIT: It's unclear about the first one, the second one is clearly on the dark side.

Sorry to contradict you so completely, but the 1999 flyby was almost perfectly on the light side:

Subsolar point, as google will tell you, is noon. Periapsis is within three "timezones" of the subsolar point. Completely light-side.

Can't find details on the 1998 flyby, but that's the one you were uncertain about, and you were wrong about the one you were certain of.

As for being able to do a dark-side flyby in stock ...

It's in complete stock system, but it's close enough to the real system in ratios for all conclusions to be transferrable. It also starts the world at a convenient point: this game is at T+20 minutes from a complete new game start. All I did was put a test payload in 100x100km orbit then:

-Ask Mechjeb's manoeuvre planner to plot advanced transfer to Eve

-Select "ASAP", create node

-add 2-3 m/s radial velocity to the manoeuvre

And we immediately get the above trajectory that goes well above Duna's orbit. I'm more than halfway to Dres on ~500 m/s more than it takes to get to Minmus!

For a bonus, trajectory deflection shows you this is also a dark side assist:

Your problem is that you simply don't have the right trajectory still. If your source isn't giving you better trajectory conditions, you'll need to set about more experimentation to find the trajectory it's trying to suggest.

Edited October 3, 2017 by Iskierka
Spelling

[Pand5461]

1 hour ago, Iskierka said:

Sorry to contradict you so completely, but the 1999 flyby was almost perfectly on the light side:

Note to self: not believe schematics from Wikipedia. I tried to draw a mental picture, and seems like speed increases after night-side flyby if it's the ascending branch of trajectory, and after day-side flyby if it's on the descending branch (ascending is Pe to Ap, descending Ap to Pe).

To the point, however, gravity assists should work roughly in the same way in full n-body physics and in patched conics.

@Nittany Tiger Velocity vector indeed just turns in the flyby body-centered frame. But that can be interpreted as spacecraft getting some velocity vector. If that vector is directed same as planet prograde, the spacecraft transfers to a higher orbit, if the vector change is pointed to planet retrograde, to lower orbit. The vector change in velocity is pointed towards the planet center. So, to get the most boost to the prograde velocity, the flyby periapsis must be close to terminator (i.e. not right opposite to the Sun but rather at the "retrograde" side of the planet).

[Iskierka]

In that regard, I think the simple wikipedia svgs represent the trajectory poorly - the UVIS diagram shows periapsis being before noon, indicating it was a descending trajectory in solar frame. Given it's close to noon though, I'm not sure there's much boost - its purpose may be more to ensure that it can cross paths with Earth for a big boost that Venus could not provide easily. Still a valuable flyby to have.

[Nittany Tiger]

@Iskierka I did wonder if my whole trajectory was off before.  Seems like it was and it wasn't just bad physics.  Might be because I was relying a lot on tools like Flyby Finder and KSP TOT.

I did think that it was possible, given a different entry into the Venus SOI, to get a boost from a dark-side flyby.

Despite studying physics in college, I have not done much work with planetary navigation, so I'm learning this as I go.  It's why I had trouble accepting the conclusion that a flyby should give a craft extra velocity because, as I said before, gravitational fields are conservative and do no net work, and in a two-body problem, you should get no net change in speed in the frame of reference of the large body.  The directional changes make a lot of sense to me, being vectors, and that's why I though the only way to get to Mars in an opposition-class approach was either with a light-side flyby of Venus or a trajectory that approaches like this:

Forgive the poor quality.  I threw this together in five minutes to quickly illustrate my suggestion.  Of course, a pericytherian that low might result in a larger trajectory change, but the point is at the right pericytherian, you should get a trajectory like that.

So, it is nice to know that KSP's base system does flybys better than I thought.

[hypervelocity]

hi guys! another quick question for you as I am having issues with the mod 

I removed Principia to place a couple satellites I had in different orbits around Earth and Moon using HyperEdit, but now that I re-installed Principia my game is crashing upon loading my save.

The logs that were generated are included below - if any charitable soul would know what might be going on, it will be very much appreciated!  Many thanks in advance!

Spoiler

FATAL.20171006-132738.5312

Log file created at: 2017/10/06 13:27:38
Running on machine: REDSPC
Log line format: [IWEF]mmdd hh:mm:ss.uuuuuu threadid file:line] msg
    @   000007FEE844EF19      principia__RenderedVesselTrajectory [0x000007FEE844EF18+220088]
    @   000007FEE83BCD4F      principia__SetBufferedLogging [0x000007FEE83BCD4E+572746]
    @   000007FEE83E8585      principia__SetBufferedLogging [0x000007FEE83E8584+750976]
    @   000007FEE83058D9      principia__FutureWait [0x000007FEE83058D8+24588]
    @   000007FEE83200F5      principia__InsertUnloadedPart [0x000007FEE83200F4+204]
    @   0000000268FC8B02      (No symbol) [0x0000000268FC8B01]
F1006 13:27:38.199720  3536 plugin.cpp:1322] Check failed: emplaced part_id: 1963220628

 

ERROR.20171006-132731.5312

Log file created at: 2017/10/06 13:27:31
Running on machine: REDSPC
Log line format: [IWEF]mmdd hh:mm:ss.uuuuuu threadid file:line] msg
E1006 13:27:31.090313  3536 interface.cpp:638] The timewarp limit for Jupiter vanishes
    @   000007FEE844EF19      principia__RenderedVesselTrajectory [0x000007FEE844EF18+220088]
    @   000007FEE83BCD4F      principia__SetBufferedLogging [0x000007FEE83BCD4E+572746]
    @   000007FEE83E8585      principia__SetBufferedLogging [0x000007FEE83E8584+750976]
    @   000007FEE83058D9      principia__FutureWait [0x000007FEE83058D8+24588]
    @   000007FEE83200F5      principia__InsertUnloadedPart [0x000007FEE83200F4+204]
    @   0000000268FC8B02      (No symbol) [0x0000000268FC8B01]
F1006 13:27:38.199720  3536 plugin.cpp:1322] Check failed: emplaced part_id: 1963220628
 

WARNING.20171006-132731.5312

Log file created at: 2017/10/06 13:27:31
Running on machine: REDSPC
Log line format: [IWEF]mmdd hh:mm:ss.uuuuuu threadid file:line] msg
E1006 13:27:31.090313  3536 interface.cpp:638] The timewarp limit for Jupiter vanishes
    @   000007FEE844EF19      principia__RenderedVesselTrajectory [0x000007FEE844EF18+220088]
    @   000007FEE83BCD4F      principia__SetBufferedLogging [0x000007FEE83BCD4E+572746]
    @   000007FEE83E8585      principia__SetBufferedLogging [0x000007FEE83E8584+750976]
    @   000007FEE83058D9      principia__FutureWait [0x000007FEE83058D8+24588]
    @   000007FEE83200F5      principia__InsertUnloadedPart [0x000007FEE83200F4+204]
    @   0000000268FC8B02      (No symbol) [0x0000000268FC8B01]
F1006 13:27:38.199720  3536 plugin.cpp:1322] Check failed: emplaced part_id: 1963220628

 

INFO.20171006-132731.5312

Log file created at: 2017/10/06 13:27:31
Running on machine: REDSPC
Log line format: [IWEF]mmdd hh:mm:ss.uuuuuu threadid file:line] msg
I1006 13:27:31.025310  3536 interface.cpp:462] Initialized Google logging for Principia
I1006 13:27:31.027310  3536 interface.cpp:463] Principia version 2017092006-Cesàro-0-ga65bd108b3e1684464bef72db30d3beae71bbd67 built on 2017-09-16T14:28:38Z by Microsoft Visual C++ version 190024213 for Windows x86-64
I1006 13:27:31.027310  3536 interface.cpp:476] Base address is 000007FEE82B0000
I1006 13:27:31.032310  3536 interface.cpp:650] principia.ksp_plugin_adapter.PrincipiaPluginAdapter.OnAwake()
I1006 13:27:31.089313  3536 interface.cpp:247] Destroying Principia plugin
I1006 13:27:31.089313  3536 interface.cpp:253] Plugin destroyed
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Pluto to 110000 m; its atmosphere extends to 110000 m and timewarp is allowed above 5000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Charon to 1000 m; its atmosphere extends to 0 m and timewarp is allowed above 1000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Neptune to 1250000 m; its atmosphere extends to 1250000 m and timewarp is allowed above 5000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Triton to 110000 m; its atmosphere extends to 110000 m and timewarp is allowed above 1000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Uranus to 1400000 m; its atmosphere extends to 1400000 m and timewarp is allowed above 5000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Saturn to 2000000 m; its atmosphere extends to 2000000 m and timewarp is allowed above 5000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Iapetus to 1000 m; its atmosphere extends to 0 m and timewarp is allowed above 1000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Titan to 600000 m; its atmosphere extends to 600000 m and timewarp is allowed above 130000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Rhea to 2000 m; its atmosphere extends to 0 m and timewarp is allowed above 2000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Dione to 2000 m; its atmosphere extends to 0 m and timewarp is allowed above 2000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Tethys to 2000 m; its atmosphere extends to 0 m and timewarp is allowed above 2000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Enceladus to 1000 m; its atmosphere extends to 0 m and timewarp is allowed above 1000 m
I1006 13:27:31.090313  3536 interface.cpp:650] Set manageability threshold for Mimas to 1000 m; its atmosphere extends to 0 m and timewarp is allowed above 1000 m
E1006 13:27:31.090313  3536 interface.cpp:638] The timewarp limit for Jupiter vanishes
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Jupiter to 1550000 m; its atmosphere extends to 1550000 m and timewarp is allowed above 0 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Callisto to 10000 m; its atmosphere extends to 0 m and timewarp is allowed above 10000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Ganymede to 5000 m; its atmosphere extends to 0 m and timewarp is allowed above 5000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Europa to 5000 m; its atmosphere extends to 0 m and timewarp is allowed above 5000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Io to 10000 m; its atmosphere extends to 0 m and timewarp is allowed above 10000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Mars to 125000 m; its atmosphere extends to 125000 m and timewarp is allowed above 5000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Deimos to 200 m; its atmosphere extends to 0 m and timewarp is allowed above 200 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Phobos to 200 m; its atmosphere extends to 0 m and timewarp is allowed above 200 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Earth to 140000 m; its atmosphere extends to 140000 m and timewarp is allowed above 140000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for the Moon to 5000 m; its atmosphere extends to 0 m and timewarp is allowed above 5000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Venus to 145000 m; its atmosphere extends to 145000 m and timewarp is allowed above 145000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Set manageability threshold for Mercury to 5000 m; its atmosphere extends to 0 m and timewarp is allowed above 5000 m
I1006 13:27:31.091313  3536 interface.cpp:650] Serialization has 470 chunks
I1006 13:27:31.091313  3536 interface.cpp:291] Begin plugin deserialization
I1006 13:27:31.434334  3536 interface.cpp:319] End plugin deserialization
I1006 13:27:31.482336  3716 plugin.cpp:1105] principia::ksp_plugin::internal_plugin::Plugin::ReadFromMessage
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000000D54AEE0
I1006 13:27:31.738350  3716 pile_up.cpp:254] Destroying pile up at 000000001DAEF490
I1006 13:27:38.176719  3536 interface.cpp:650] Setting GameSettings.ORBIT_WARP_DOWN_AT_SOI to false
I1006 13:27:38.199720  3536 vessel.cpp:63] Vessel Polar Relay Network (b1a79512-5fb0-44cc-8fa7-5009a33e8118) is now known as Polar Relay 1
I1006 13:27:38.199720  3536 plugin.cpp:364] Inserted unloaded vessel Polar Relay Network Debris (27b58490-7c38-4f3a-8c8e-92e607097762)
    @   000007FEE844EF19      principia__RenderedVesselTrajectory [0x000007FEE844EF18+220088]
    @   000007FEE83BCD4F      principia__SetBufferedLogging [0x000007FEE83BCD4E+572746]
    @   000007FEE83E8585      principia__SetBufferedLogging [0x000007FEE83E8584+750976]
    @   000007FEE83058D9      principia__FutureWait [0x000007FEE83058D8+24588]
    @   000007FEE83200F5      principia__InsertUnloadedPart [0x000007FEE83200F4+204]
    @   0000000268FC8B02      (No symbol) [0x0000000268FC8B01]
F1006 13:27:38.199720  3536 plugin.cpp:1322] Check failed: emplaced part_id: 1963220628
 

EDIT: I think the aforementioned crash is related to the vessels I have Hyper-Edited to different locations, as I have tried opening another savegame I have without any craft in space and it worked perfectly. 

The crafts I HyperEdited are 4 Earth Satellites @ 10,000km & 90° inclination circular orbits, 4 Moon Satellites @ 7,500km & 90° inclination circular orbits, and 1 Moon Satellite @ 150km & 90° inclination circular orbit.

EDIT 2 & 3: I think the issue might be related to RSS's timewarpAltitude limit issues described a few pages back - I am now downloading RSS's master from github and replacing the configs for all bodies - I will let you know if that fixed it. Did not work - I copied the contents of RSS's Current Repository RealSolarSystem\RSSKopernicus into my GameData and now the game gets stuck in the Loading screen after having loaded all assets & modules.

Edited October 6, 2017 by hypervelocity

[eggrobin]

23 hours ago, hypervelocity said:

I removed Principia to place a couple satellites I had in different orbits around Earth and Moon using HyperEdit, but now that I re-installed Principia my game is crashing upon loading my save.

The state of Principia got desynchronized from the state of the game in the process; the only way out of this is probably to destroy the Principia state from your save, so that Principia then reconstructs things anew (note that histories, flight plans, etc. will be lost).

In your .sfs, remove the entire SCENARIO node whose name is PrincipiaPluginAdapter (this node has a lot of hexadecimal entries called serialized_plugin; the logs say that in your save, there are 470 of them).

Once this is done, start the game with Principia installed; note that the game might take a while to load, as Principia will need to simulate the solar system up to the current time.

[Nittany Tiger]

I'm finding the target reference frame plot (LVLH@E) super-useful for planning rendezvous.  This should be in stock.  A little hard to get used to at first, but I find it better than stock close approach markers since this reference frame lets me see how one vessel moves with respect to the other.  Means I can tell which direction to adjust a maneuver and potentially figure out the lowest dV approach.

The more I use this mod, the more I don't think I can live without it in stock.

[Mr. Quark]

Does this still work with 1.3.1?

EDIT: No it crashes on loading of save or starting new one.

Edited October 11, 2017 by Mr. Quark

[hypervelocity]

On 7/10/2017 at 12:53 PM, eggrobin said:

The state of Principia got desynchronized from the state of the game in the process; the only way out of this is probably to destroy the Principia state from your save, so that Principia then reconstructs things anew (note that histories, flight plans, etc. will be lost).

In your .sfs, remove the entire SCENARIO node whose name is PrincipiaPluginAdapter (this node has a lot of hexadecimal entries called serialized_plugin; the logs say that in your save, there are 470 of them).

Once this is done, start the game with Principia installed; note that the game might take a while to load, as Principia will need to simulate the solar system up to the current time.

many many thanks for your help @eggrobin! the .SFS was daunting, at 17,000 pages - I removed the whole node but the game got stuck at re-load (assuming Principia was simulating the solar system but got stuck at some point) so I ended up removing the save game and creating a new one, placing all my craft before re-installing Principia - this worked like a charm and I am now enjoying the mod! very grateful to all of you guys! <3

[scimas]

On 10/11/2017 at 4:29 PM, Mr. Quark said:

Does this still work with 1.3.1?

EDIT: No it crashes on loading of save or starting new one.

It's not updated for 1.3.1 yet, but I guess the next version will support 1.3.1, at least their change log draft says so. They release updates every new moon, so the next one should be around 20th October.

[Scotskerb]

I updated my install of KSP to 1.3.1, and have no way of reverting to 1.3.0. Now I have to wait until the next update of Principia, which, apparently, doesn't update until the new moon.