[WIP][1.8.1, 1.9.1, 1.10.1, 1.11.0–2, 1.12.2–5] Principia—version ‎Καραθεοδωρή, released 2024-04-08—n-Body and Extended Body Gravitation

[Delay]

2 minutes ago, Tonas1997 said:

could it theoretically be implemented?

I reckon that would break physics.

[hypervelocity]

@Tonas1997 you shouldn't worry too much about that - I have been playing Principia for a long while now and stationkeeping is the least of my "problems". I have orbital relays around the Earth, Moon and Mars and I check on them/adjust once every 1-2 in-game years. You should definitely give this mod a try, you are not going back to stock physics, believe me! 

[AloE]

@GregroxMun @pleroy

@eggrobin

Thanks, all of you, for creating these very special mods!

I have not seen this 'fix' posted else where...my TRAPPIST install just never would 'start a new game' even though Principia or SLIPPIST would run  just fine in 1.4.x installed by themselves...

so I dug into the glog and noticed the error:

F0825 23:37:01.099138 32236 interface.cpp:765] missing gravity model for Sun

which led me to look in the .cfg files & google for "%cbNameLater = Trappist-1" and, thus, found GregroxMun's June '"fixed trappistpatch" in PasteBin :

https://pastebin.com/i7dvVZYZ

excerpt:

1. //you also need to modify trappist_gravity_model.cfg and the initial state file, changing name = Trappist-1 to name = Sun
2. @Kopernicus:AFTER[aSLIPPIST-1] {
3.   @Body[Sun] {
4.     @Properties {
5.       !mass = delete

I made the indicated changes in the various .cfg files in "Trappist-1 for Principia folder" and now all seems to work & create TRAPPIST-1 with  1.4.5, Desargues, & SLIPPIST 0.6.0

I still get the old files that need to be corrected when I download from the link provided in the Principia GIT FAQ , so might be worth a quick check:

• Download the trappist-1 for principia dedekind.zip file, unzip it, and drop the Trappist-1 for Principia folder in the GameData folder of your installation of KSP.

https://github.com/mockingbirdnest/Principia/wiki/Installing,-reporting-bugs,-and-frequently-asked-questions#installing-trappist-1-for-principia

If the above download file is correct from your end and/or there are more current .cfg for me to use for TRAPPIST for Principia, please let me know! 

(e.g. maybe my google drive is playing tricks with me by pulling an old version or something...)

Thanks again & Kind regards!

 

Edited August 26, 2018 by AloE
add additional acknowledgement & request clarification

[T-10a]

I've been making a custom system arrangement using Kopernicus configs, would testing them in Universe Sandbox² be a good idea to ensure the system arrangement doesn't end up collapsing stock-Jool style? 

[pleroy]

On 8/26/2018 at 12:59 AM, AloE said:

I have not seen this 'fix' posted else where...my TRAPPIST install just never would 'start a new game' even though Principia or SLIPPIST would run  just fine in 1.4.x installed by themselves...

so I dug into the glog and noticed the error:

F0825 23:37:01.099138 32236 interface.cpp:765] missing gravity model for Sun

Ah, thanks a lot for reporting this, @AloE.

It turns out that while we coordinated with @GregroxMun when he was developing version 0.6.0 of his SLIPPIST-1 mod, we never fixed the link if the FAQs.  So the version that you downloaded (trappist-1 for principia dedekind.zip) was designed for 0.5.x and had plenty of problems, one of which was an incompatibility with Kopernicus that caused the crash that you encountered.

I have fixed the link in the FAQs to point to trappist-1 for principia δημόκριτος.zip.  I suggest that you download this version and install it instead of what you have at the moment.  It is better in a number of ways, in particular better alignment of the planetary textures, more realistic radius and atmospheres, data suitable for EVE and Scatterer, etc.  (See PR #1856 and #1859 for details.)

Apologies for the confusion caused by the outdated FAQs.

 

Edited August 29, 2018 by pleroy
Typos.

[flyby2412]

Does anyone have the file for Principia 1.2.1? I want to run Realism Overhual and Realistic Proggression with Principia, but so far, RP-0 doesn't have a 1.3.1 release as far as i know

[Damien212]

15 hours ago, flyby2412 said:

Does anyone have the file for Principia 1.2.1? I want to run Realism Overhual and Realistic Proggression with Principia, but so far, RP-0 doesn't have a 1.3.1 release as far as i know

Install RP-0 dev (RP-1) for 1.3.1 instead as detailed here

[AloE]

15 hours ago, flyby2412 said:

Does anyone have the file for Principia 1.2.1? I want to run Realism Overhual and Realistic Proggression with Principia, but so far, RP-0 doesn't have a 1.3.1 release as far as i know

If you decide to use 1.2, assuming the Principia team does not mind, I do have my 1.2 archives with various older Principia versions I could share with you...

[pleroy]

20 hours ago, flyby2412 said:

Does anyone have the file for Principia 1.2.1? I want to run Realism Overhual and Realistic Proggression with Principia, but so far, RP-0 doesn't have a 1.3.1 release as far as i know

@flyby2412: Cramer, the last version of Principia to support 1.2.2, can be obtained at https://goo.gl/XgRdRP.  No support, no bug fixes, no questions answered.

This being said, we recommend to use RP-1 with 1.3.1 and the latest Principia.  Other people seem to have been successful with that setup.

[AloE]

On 8/29/2018 at 9:49 PM, pleroy said:

Ah, thanks a lot for reporting this, @AloE.

It turns out that while we coordinated with @GregroxMun when he was developing version 0.6.0 of his SLIPPIST-1 mod, we never fixed the link if the FAQs.  So the version that you downloaded (trappist-1 for principia dedekind.zip) was designed for 0.5.x and had plenty of problems, one of which was an incompatibility with Kopernicus that caused the crash that you encountered.

I have fixed the link in the FAQs to point to trappist-1 for principia δημόκριτος.zip.  I suggest that you download this version and install it instead of what you have at the moment.  It is better in a number of ways, in particular better alignment of the planetary textures, more realistic radius and atmospheres, data suitable for EVE and Scatterer, etc.  (See PR #1856 and #1859 for details.)

Apologies for the confusion caused by the outdated FAQs.

 

Thank you :-)  Pretty clouds and scattered atmosphere now working in TRAPPIST1 in both 1.3.1 & 1.4.5... I foresee many hours in my future helping someone who very much enjoys the result of your efforts engage with plenty of transfer exploration & colony experiments this winter on days under the Seeland fog.  Using RO with both TRAPPIST1 & RSS Principia arranged solar system models...an insightful solar system contrast/comparison.  Thanks again!

[AloE]

@pleroy

Do I understand correctly that the TRAPPIST-1 system starts at epoch : "JD2457000.000000000" =  UTC Noon  Monday 2014 December 8 ?

[pleroy]

6 minutes ago, AloE said:

@pleroy

Do I understand correctly that the TRAPPIST-1 system starts at epoch : "JD2457000.000000000" =  UTC Noon  Monday 2014 December 8 ?

@AloE: Yes, that's correct.  That's mostly a round number (in JD) that's happens to fall shortly before the first observation of TRAPPIST-1.  We run a fairly complex and expensive optimization to determine orbital elements that match the observed transits, so it's convenient to start a short time before the first observation.  Also, many sources give dates like "7282.80570" where the leading JD245 is omitted.

[eggrobin]

For the new moon (lunation number 231), the new release (Descartes) is out.

Important note for mac users: Principia no longer supports macOS El Capitan, as that version is no longer supported by Apple. We now require macOS Sierra or later.

As a consequence, we can use shared_mutex on mac, so there should be noticeable performance improvements for macOS users.

We have added generalized Runge-Kutta-Nyström methods, which allow for a more accurate prediction of burns that are fixed in the Frenet frame.

See the change log for more details.

 We support two versions of KSP: downloads are available for 1.4.5 and 1.3.1. Make sure you download the right one (if you don't, the game will crash on load).

[sjsharks39]

Has anyone ever managed to get this working with GPP @ 10.625x rescale? This would be icing on the cake for me but I even found the principia planet pack patch thread and GPP is still "planned".

[AloE]

@eggrobin  

I am trying to display in game the common calendar date of the 'Principia' time in the 'TRAPPIST-1 for Principia" & would much appreciate your insight on how to use the RSSTimeFormater config resulting from your Git pull request: #3 for it: https://github.com/KSP-RO/RSSTimeFormatter/pull/3

which I am under the impression would enable me to accomplish that, however I appear to not be understanding one or more important things.

I do not see anything like the following in any of the .cfg in "TRAPPIST-1 for Principia", so is such a RSSTimeFormater config to be placed in game in a specifically named .cfg file in KSP GameData, or is it a config that needs to be used when making the RSSTimeFormater.dll ?

& would a RSSTimeFormater config for "TRAPPIST-1 for Principia"  look like the following?

RSSTimeFormatter {
dateFormat = dd.MM.yyyy
epoch = 2014-12-08T12:00:00
}

Thanks for your insights!

reference note from eggrobin on GitHub:

Quote

"Note that in practice epoch should be combined with something to offset the initial positions of the celestials in-game, e.g., Principia's game_epoch setting. Principia parses dates that are either Julian dates or a fairly strict subset of ISO 8601, which is why I specifically checked the 1993-01-01T00:00:00 format for the epoch of RSSTimeFormatter, since Principia will accept that format."

[eggrobin]

On 9/10/2018 at 11:30 AM, AloE said:

I am trying to display in game the common calendar date of the 'Principia' time in the 'TRAPPIST-1 for Principia" & would much appreciate your insight on how to use the RSSTimeFormater config resulting from your Git pull request: #3 for it: https://github.com/KSP-RO/RSSTimeFormatter/pull/3

This is a good idea, we should recommend it.

Quote

I do not see anything like the following in any of the .cfg in "TRAPPIST-1 for Principia", so is such a RSSTimeFormater config to be placed in game in a specifically named .cfg file in KSP GameData, or is it a config that needs to be used when making the RSSTimeFormater.dll ?

The TRAPPIST-1 for Principia config isn't currently intended to support RSSTimeFormatter (although it probably should), so it has no configuration for it.

KSP configuration is just a matter of having some cfg file with the right nodes somewhere under GameData, which file it comes from matters little (it can have an effect on the order of ModuleManager patches, but this is fairly advanced KSP configuration).

Quote

& would a RSSTimeFormater config for "TRAPPIST-1 for Principia"  look like the following?

RSSTimeFormatter {
  dateFormat = dd.MM.yyyy
  epoch = 2014-12-08T12:00:00
}

 

Yes, at least if you want Swiss-style dates. :-)

In particular, `epoch` should be equal to the `game_epoch` setting from Principia's principia_initial_state.

An important note is that the time shown will be the time on Earth in Temps Terrestre (TT) at which the system will be seen in that configuration from Earth, and that there are about 40 light-years between from here to TRAPPIST-1; further TRAPPIST-1 is moving at about 80 km/s with respect to the solar system.

[AloE]

10 hours ago, eggrobin said:

In particular, `epoch` should be equal to the `game_epoch` setting from Principia's principia_initial_state.

An important note is that the time shown will be the time on Earth in Temps Terrestre (TT) at which the system will be seen in that configuration from Earth, and that there are about 40 light-years between from here to TRAPPIST-1; further TRAPPIST-1 is moving at about 80 km/s with respect to the solar system.

RE: TT...yes, one impetus has been that my son enjoys exploring TRAPPIST-1 as 'observed' from equipment on/near Earth at various approximate dates where the light left that system at specific X,Y ages of his parents...( some Swiss kids & time...lol ;-)  hmmm...at 80 km/s that is a change of about 1 light day per ~10 Earth years I think...

Quote

Example format strings: dd.MM.yyyy, M/d/yyyy, dd/MM/yyyy, yyyy/MM/dd, yyyy. M. d..

maybe I just could not find it over at github...what epoch formats are currently supported by RSSTimeFormater?  I see that RSSTimeFormater does ok with the following in the "Trappist1.cfg" file I added

epoch = 2014-12-08T12:00:00

but it does not like the epoch format I see in trappist_initial_state_jd_2457000_000000000.cfg => game_epoch = JD2457000.0 as  epoch = JD2457000.0 or epoch = 2457000.0 for example in my "Trappist1.cfg"

& Thank you, this is fun!

[SnailnamedSnail]

On 9/10/2018 at 7:51 AM, sjsharks39 said:

Has anyone ever managed to get this working with GPP @ 10.625x rescale? This would be icing on the cake for me but I even found the principia planet pack patch thread and GPP is still "planned".

With 6.4 rescale i get strange bug: the radius of the orbits remained old and the planets move on a rails, but graphical part of orbits built by Principia (it's high eccentricity ellipses, the old speeds are too small). pLeAsE! add "rescale" compatibility for 1.4.5 in next release!

[scimas]

2 hours ago, SnailnamedSnail said:

but graphical part of orbits built by Principia

As far as I know principia does not draw the orbits of planets, only of ships and asteroids. 

[eggrobin]

12 hours ago, AloE said:

RE: TT...yes, one impetus has been that my son enjoys exploring TRAPPIST-1 as 'observed' from equipment on/near Earth at various approximate dates where the light left that system at specific X,Y ages of his parents...( some Swiss kids & time...lol ;-)  hmmm...at 80 km/s that is a change of about 1 light day per ~10 Earth years I think...

It's only 54 km/s in the radial direction, the rest is from tangential motion.

I was mostly mentioning relative velocity because of relativistic effects, since you generally work with time scales in which the system of interest is at rest: people use geocentric coordinate time (Temps-Coordonnée Géocentrique, TCG) or its linear scaling terrestrial time (Temps Terrestre, TT) when working with satellites of the Earth, but barycentric coordinate time (Temps-Coordonnée Barycentrique, TCB), the time coordinate of the barycentric celestial reference system (BCRS) when working with missions in the solar system. Hypothetical inhabitants of the TRAPPIST-1 system would similarly work with the time coordinate of a reference system in which the TRAPPIST-1 system is at rest, rather than one in which it moves at considerable speed, so that it is hard to assign precise and useful meaning to "the time at which the light left TRAPPIST-1":

• "the time at which the light left TRAPPIST-1 in the BCRS" is well-defined, but:
  • odd from the perspective of the denizens of TRAPPIST-1e who would see BCRS clocks moving past them at 80 km/s, and therefore running slow by about 1 s per year;
  • not useful from the perspective of our solar system, where it takes 40 years for that to actually be observed.
• "the time at which the light left TRAPPIST-1 in a reference system in which the barycentre of the TRAPPIST-1 system is at rest" is not well-defined (since TRAPPIST-1 clocks and BCRS clocks tick at different rates in either frame, you need to decide when they are aligned, which makes your dates essentially arbitrary).

As a result, we use "the time at which the light reached Earth in the terrestrial frame", which at least is useful from an observational standpoint. Note of course that TT is different from UTC, so what you see is not quite civil time.

12 hours ago, AloE said:

Quote

Example format strings: dd.MM.yyyy, M/d/yyyy, dd/MM/yyyy, yyyy/MM/dd, yyyy. M. d..

 

maybe I just could not find it over at github...what epoch formats are currently supported by RSSTimeFormater?  I see that RSSTimeFormater does ok with the following in the "Trappist1.cfg" file I added

epoch = 2014-12-08T12:00:00

 but it does not like the epoch format I see in trappist_initial_state_jd_2457000_000000000.cfg => game_epoch = JD2457000.0 as  epoch = JD2457000.0 or epoch = 2457000.0 for example in my "Trappist1.cfg"

The example format strings are for the dateFormat setting, which, as you have seen, controls the format in which RSSTimeFormatter shows the date. dd/MM/yyyy will give you French-style dates, dd.MM.yyyy Swiss and German-style ones, yyyy年M月d日 Chinese-style ones, etc.

It is unrelated to the epoch setting.

The epoch setting will take whatever DateTime.TryParse will accept. DateTime.TryParse does not accept Julian dates (.NET is not an astronomy framework). In practice, I recommend using ISO 8601 extended format calendar dates, i.e. things like 2014-12-08T12:00:00, since this is unambiguous and also works for Principia.

Edited September 12, 2018 by eggrobin

[AloE]

 

On 9/12/2018 at 9:53 PM, eggrobin said:

The epoch setting will take whatever DateTime.TryParse will accept. DateTime.TryParse does not accept Julian dates (.NET is not an astronomy framework). In practice, I recommend using ISO 8601 extended format calendar dates, i.e. things like 2014-12-08T12:00:00, since this is unambiguous and also works for Principia.

Thank you for clarifying that it is DateTime.TryParse.   In the future I will use the format that you recommend & that works in Principia as wel,.

& for clarifying & reminding me that an image playing around with time formats does not make a clear separator of different questions,

& for the useful distinctions regarding several reference systems & the respective time coordinate for each.

[MaltYebisu]

I have a small question on terminology. 

Principia use different terminology for the delta-v directions (Prograde ==> Tangent etc). My question is: how do you pronounce the words "-tangent", "-normal", and "-binormal"? How would you use them in a sentence? Is it "this manoeuvre is 10 m/s -normal and 20 m/s -tangent" or something else?

Anyhow, thank you very much for this fantastic mod. It is a little hard on my potato laptop, but I'm having fun becoming a novice at rendezvous and having to struggle to go to the Mun again. 

 

Edit to clarify my question a bit:

 I'm asking about the "-" part of the words "-tangent", "-normal", and "-binormal". Do you pronounce it "anti tangent", "negative tangent", or something else?

Edited October 6, 2018 by MaltYebisu
To clarify

[Clockwork13]

For me, Principia crashes when trying to load a save. I know the problem is Principia, however looking through the logs I couldn't find anything that seemed related to this. What I did find, however was that an stderr.log was being created every time it crashes. I'm on Debian Linux. I think this might mean I'm missing a C Library or something like that. Any thoughts?

The output of stderr.log is as follows:

/home/user/.steam/steam/steamapps/common/Kerbal Space Program/KSP.x86_64: symbol lookup error: GameData/Principia/Linux64/principia.so: undefined symbol: _ZNSt3__119__shared_mutex_baseC1Ev

[pleroy]

4 hours ago, Clockwork13 said:

The output of stderr.log is as follows:

/home/user/.steam/steam/steamapps/common/Kerbal Space Program/KSP.x86_64: symbol lookup error: GameData/Principia/Linux64/principia.so: undefined symbol: _ZNSt3__119__shared_mutex_baseC1Ev

@Clockwork13: As mentioned in the FAQs, you need version 6.0-2 of libc++.  You must have a rather ancient version to be missing shared_mutex (it was added in the 3.4/3.5 timeframe).

[Clockwork13]

8 hours ago, pleroy said:

@Clockwork13: As mentioned in the FAQs, you need version 6.0-2 of libc++.  You must have a rather ancient version to be missing shared_mutex (it was added in the 3.4/3.5 timeframe).

It looks like I have 3.5 installed for some reason, so that must be it. Thanks!