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Sun Synchronous Orbit Calculator SSO Calculator Online Abstract In the Kerbal Space Program, planets are regular spheres. After adding Principia, planets like Kerbin do not have sun-synchronous orbits. And this tool can generate configuration file of Principia, so as to add the second-order spherical harmonic coefficient j2 to the stock planet to help players successfully enter the sun-synchronous orbit of the stock planet. At the same time, this tool also supports the calculation of relevant parameters of the sun-synchronous orbit in the RealSolarSystem environment. Dependencies The newly generated xx_xx_GravityModels.cfg file requires support from Kopernicus. If you want to enter a sun-synchronous orbit, you must have the support of Principia. You must download Planet Stock Essentials.cfg from Spacedock or GitHub into GameData to use it, especially for players who use Planet Stock. Chinese Version Tutorial (obsolete) Credits @SirMortimer Kopernicus configuration file. @Nazfib Code help for calculating sun-synchronous orbit inclination and other formulas. @Charon_S丶 KSP players have provided help for adding second-order spherical harmonic coefficient terms. @PrincipiaTeam Provide file support for planetary data in the RSS environment. @tinygrox Thank you for his suggestions on language and unit options. NewBing The planetary rotation period under RSS is provided.

Yesterday I started a new game with Principia. I tried to rendezvous two ships on low Mun orbit (Pe=Ap=15km) . Being new to Principia, I wasted a lot of fuel tweaking around and ended up finding that I had only 174m/s to go home. I found that if I put all of the delta-v into a prograde burn I would reach an unstable orbit, where there might be some ways to leave Mun. But I failed to find such ways. Do those ways exist? Is there a minimal delta-v for this transfer? If there really is one, then what is it?

Exploring Lagrange Points & Rectilinear orbits...Let's start with the Moon Retrograde Square Orbit Why explore this intriguing region of space in KSP with Principia & RSS? The upcoming ESA/NASA/JAXA Lunar Gateway DSL station & SLS Artemis III+ missions & the 'mind puzzle' of navigating the 'shape' of forces in this region of space. One simple way to start exploring the 'shape' of force potentials around the Moon gravity well in the Earth-Moon system is the DRO 'Lunar Retrograde Square': an orbit from near L2 towards L5, back near L1 then towards L4, & falling back towards L2... Update: Principia added an EML reference frame -- with the option to show equipotential lines for the sum of forces associated with gravity & rotation in the plane defined by the orbital of the Moon around Earth... These equipotential lines are shown for a single plane & for the 'current time' & do shift slightly with the Moon's distance from Earth i.e. the location of the equipotential lines will be slightly different when a craft actually reaches a given point on the Principia projected fuchsia or dashed paths... the shift is quite noticeable over time along the direction of an imaginary line say from L4 to L5. a visual explanation of equipotential in a video by Scott Manley The EML frame offers an insightful way to visualize the dynamics shaping the Lunar Retrograde Square Orbit... For example, for the 'square' orbit plotted in the MCI frame... see how a lower AP creates a more rounded 'corner' (e.g. see the AP on the L4 side of the orbit in the screenshots below); where as, traveling further towards L4 or L5 creates a sharper 'corner' (e.g. see the AP on the L5 side of the orbit in the screenshots below)... well, that is at least until you get close to a transfer to L4 or L5 where you will see a loop 'ear' corner instead. Note: To help interpret the craft path, I have added to the screenshots in yellow text approximate L point information...this is _not_ shown in game. The above animation shows the 'Square' orbit over 7 years in MCI (Moon Centered Inertial) frame (fyi...with the small vessel in this save the 'square' path persisted for about 18 years with no station keeping). Clarification: the Earth is traveling along the blue-ish arc counter-clockwise. Summary of Earth-Moon system Challenges: Challenge #1 (Beginner): "Get a feel for the dynamics that shape the 'Retro Square' orbit: Make a 'Moon Pentagon' orbit" Challenge #2 (Intermediate): 'Transfer to an Artemis III & Gateway Station type of Moon NRHO [pdf] (see animation & NASA graphic below)" Challenge #3 (Intermediate): 'Transfers along the 'Lunar Retro Square' to halo orbits around L2, L1, L4, L5' Challenge #4 (Advanced): "Moon L1 halo to Moon L2 halo transfer similar to the 2010 ARTEMIS-P1 mission (see NASA drawing below)" Challenge #5 (Advanced): "Create a 'Lunar Gateway (images post by NASA of the planned station) ' type station (module link sequence video NASA) (or a magic potatoroid mining station [Matt Lowne] ) in a long term 'Lunar Retro Square Orbit' (since a Moon NRHO might require more frequent station keeping) for ease of docked ship transfers to Moon NRHO, L2, L1, L4, L5" Challenge #6: Create an even better n-body related challenge & share it! Challenge #1: "Get a feel for the dynamics that shape the 'Retro Square' orbit: Make a 'Moon Pentagon' orbit" In the provided save, with a single less than 10s burn, turn the Retrograde "Moon Square" orbit into a "Moon Pentagon" orbit: Inspired by the @maccollo "Principia Mun Retrograde Square Orbit" during the afternoon of an 'at home from school not so well day', my son & I decided to see if a related "Square Retrograde Moon" orbit could be created in Principia RSS. Indeed, we found something similar that we could also manipulate purposefully with a single small burn at a specific time: In this 1st case, turn the "Moon Square" orbit into a "Moon Pentagon" orbit as shown in the images with a single less than 10s burn like we did (yes, that's a hint, & improvements welcome). We share this as an introduction of a thread to explore, discuss & share refined versions of this orbit as well as new saves of other intriguing orbits with the 'flight plan' of burns to reach them... Discovery either by blind fortune dragging Principia maneuver burn sliders or intricate use of KSPTOT 1.6.9 welcome! KSP version: 1.12.x Required Mods: Principia, RSS Optional Mods: RealScaleBoosters, SMURRF, KOS To load: download the "Moon Square Orbit" save create a KSP 1.12.x GameData with Principia, RSS load KSP & create a new save game, find the folder with the name you gave to that newly created save game on your hard drive & copy into that folder the "MoonSquare.sfs" Load the MoonSquare save as normal from the usual in game menu (e.g. from the Space Center screen) Find the craft in the Tracking Station & select it to fly. if you are unfamiliar with Principia here is a link to a post with some visuals & suggestions. Metrics: Orbit Uniformity & Stability (both improved revisions as well as your own original orbits welcome) Quality & Ease of the flight plan (the easier/simpler to execute the better) in the save you share discovery of a simple regular maintenance maneuver(s) would be a nice plus most importantly -- the fun factor: how much fun we all have exploring what you improve/create! Objectives: 1) Fun (with Principia RSS ;-) 2) hands on play with fascinating orbits, one barely new existed, with saves someone else took the effort to make 3) improve a save: create & share Principia 'flight plans' of maintenance burn(s) that make a given orbit more uniform & stable 4) make a new save (with a simplified mod list): and share your own flight plan for some type of cool orbit... Flight Plan to make the "Moon Square": requires RealScaleBoosters added to GameData in addition to Principia & RSS Related to Challenge #1: The recent SLS Artemis 1 mission made use of a Lunar distant retrograde orbit (DRO) [source link for animation below] (not square though ;-) The Principia EML frame is similar to the left 'Earth-Moon Pulsating Rotating Frame': Challenge #2 (Intermediate): Transfer to a SLS Artemis III & Gateway Station Moon NRHO: NASA explains why a NRHO vs DRO or low lunar orbit for Gateway station: https://www.planetary.org/space-images/near-rectilinear-halo-orbits Challenge #3 (Intermediate): 'Transfers along the 'Lunar Retro Square' to halo orbits around L2, L1, L4, L5' Challenge #4 (Advanced): "Moon L1 halo to Moon L2 halo transfer similar to the 2010 ARTEMIS-P1 mission" 2010 "ARTEMIS-P1 - The First Earth-Moon Libration Orbiter": Additional videos: NASA Scientific Visualization Studio 2010 ARTEMIS at Lagrange: "In this version, the satellite trails are are constructed in a lunar-centric inertial coordinate system so the trails reveal the motion of the satellites relative to the Lagrange points in INERTIAL space (fixed with the distant stars)" Some examples of additional orbits to explore: Near Rectilinear Halo Orbit (NRHO) "KSPTOT LVD: (Tools -> Halo Orbit Constructor menu)" Arrowstar's post with details about this new tool (link) Lissajous orbit WMAP at Sun–Earth L2,[7] Earth-Moon L points Visual Data Mission ideas: place a station, gravitational wave 'telescope' (link), or comsat(s) at the stable Earth-Moon L4 & L5 Note: L3 is an unstable L point = requires small periodic maintenance burns. Images: source source source

I'm making this topic largely in case someone else comes across the same issue I did, so that they can (potentially) find the answer to their problem sooner rather than later. The title says it all, basically. Principia, which changes the way physics are handled in KSP, does not play nice with the Firespitter plugin-- specifically, "FSengineBladed" and "FSbladeLiftSurface". I've looked through the code but I haven't found an obvious source for this incompatibility, but I am certain that it comes from those two classes conflicting with/improperly using Principia's slightly different physics. In practice this incompatibility manifests basically only with helicopter parts. If you throttle up a helicopter blade while Principia is installed, your helicopter will flop from side to side and bounce up and down like a fish out of water. It's quite funny, actually. Tellingly, the "current force" field of the rotor will always remain at 0. Simply put, the parts won't work for their intended purpose. Remove Principia, and boom- Helicopters can take off, hover, and crash catastrophically into the VAB just as you would expect. I know for certain that this issue affects the Firespitter rotors, as well as those from "Airplane Plus". Another separate but very similar issue occurs with lifting bodies that use the mod "Hooligan Labs Airships"-- the parts from that mod also bounce about like convulsing fish when you attempt to use them in conjunction with Principia, so I can only assume that something very similar is causing both issues. At the moment, since my cursory knowledge of unity modding doesn't afford me the ability to really find out what's wrong, and possibly fix it, There's not much that can be done if you find yourself with the same mod conflict. However, on the bright side, in the case of "airplanes plus", many of the parts cause no conflicts: so, you could simply hide the offending parts with something like "Janitor's Closet", and not encounter any problems. Hopefully this little write-up serves to help someone figure out why their helicopters just won't work, without having to check for mod incompatibilities one at a time for hours on end like I did

I have searched every where on the internet but can't find a guide on how to install principia. I have the zip file but don't know what to do with it.(Win 10)

Hello, things that I would really like to see in KSP 2 are surface fixed reference frames, let me elaborate: There is this mod called principia, it models n-body gravitation and has an option to manually change reference frames, one of the options is a surface-fixed one. This one is really useful for analyzing how a satellite drifts in say a geostationary orbit, or even a Molniya orbit, and is really nice for fine tuning orbits like that. Here is an example how this would look in a RSS KSP 1 system in a geostationary orbit: Here you see a satellites history as it moves into GEO (using RSS + principia). It is clearly visible that at the final trajectory, the satellite has very minimal movement with reference to the fixed surface of Earth (in map view). In principia there is also this other reference frame, where you can select a target, and the target becomes the center of the reference frame (like the visual effect you'd get when you get an encounter with another body), this is way more intuitive to look at than 2 closest approach markers as we would have in stock KSP 1. I would really enjoy these features in KSP 2, if possible.

I am trying hard to install Principia for 1.7.1. But I can't figure it out. Why 1.7.1? Because I do not want to reinstall all my mods again. Thanks for Response.

I'm running KSP 1.8.1 from Steam with a fair number of mods: Realism Overhaul and all its dependencies, Real Solar System and its dependencies, MechJeb2, and Principia. My problem is that I can load my worlds (albeit slowly) and open the launchpad and set a target in map view, but the moment I try engaging the autopilot in MechJeb (or pausing the game—that seems to cause the same problem) the game freezes and I have to force close it. I'm running it from Steam with the -force-glcore launch option so the game doesn't run out of memory (I have 16gb RAM and my PC's specs should not be a bottleneck). I've attached my Player.log, KSP.log, and a video with the replication steps here: https://www.dropbox.com/sh/z8024cpf160fjlq/AABq_k5UnXyunaHYc75tk_cKa?dl=0. (Note that the video has like entire minutes of nothing happening; this was actually during the loading screens. Sorry for the choppy video. It didn't look that bad from my end.) I'm trying to launch Raidernick's Luna 13 into Earth orbit at the lunar plane of orbit. I'm confused because this worked before (about a month ago) without major issues, but trying it now the game pretty much always freezes up. Even funnier is that the one time I record my screen to show it, it actually doesn't freeze the first time around! It did freeze when I disengaged and re-engaged the autpilot though, so the problem really is still there. I know I'm not running out of RAM or anything because when I open the task manager nothing is excessively full (the RAM sits around 70% full when the game is running). I'd really appreciate it if you guys could give me a hand with getting my game functional again. I know RO works for the people who use it so I'm kinda sad that it doesn't seem to be working for me.. Thanks in advance!

Hello. I'm a bit of a forum lurker, but I hope this can change that. I'll be documenting most of my missions with Principia, Ferram Aerodynamics Research, and Restock++ in one of my sandbox saves. I'll try to post reports actively, but don't be surprised if I don't post for the better part of a week (or longer). Images will be in spoilers to prevent atrocious loading times, and links to them may be below the spoilers. This is my save as of November 11, 2020. I have lots of satellites, with no interplanetary missions yet. \/ https://imgur.com/a/eUQCqg9 This is the SSTO I have made that can launch the ion powered relay satellites into orbit with around 1600 delta V to spare. It takes advantage of the lifting body aspect of FAR to shave off weight that would be added by wings, and also because it looks awesome. It is also the best SSTO I have ever made, by far. It could probably go to the Mun and back, and that's excluding the ion surprise inside. One of the downsides is it needs a lot of space to get off the ground which makes it quite hard to get it into a polar orbit. \/ https://imgur.com/a/KbyZHYU I will be uploading more reports, and if anyone has ideas I'd be happy to try and make them into a craft or mission.

I wrote a couple of config files that make OPM stable with Principia. You can get them here. What the configs do: Reinstate the stabilized Jool system that is usually provided by Principia (using planet packs causes Principia to ignore stabilizing the Jool system). Moves Ovok into a high retrograde orbit around Sarnus, preventing it from causing a Principia error around year 15.

Hi. I found this amazing mod that generates n-body orbital mechanics known as Principia, by @eggrobin. Even the planets work with the new mechanics, knocking each other's orbits around in a quite interesting fashion, the same way it's done in real life. It even reworks the Jool system to make sure the moons don't go completely out of whack. The problem is, it only seems to work with stock KSP. There are many planet packs out there which do not get reworked for compatibility with this mod. What I am doing with Planet Patches is adding a patch for each planet mod I come across that has unstable orbits with Principia, repositioning the unstable bodies to make them stable. Modified Planet Packs: Planned Planet Packs: I am open to requests. In fact, I plan on building this entire thing on requests Requests I will not take: Half-baked mods - what I mean here is, mods that are so in-development that they can't even work properly on their own. For example, if the SOIs are insanely sized in a way that completely messes up one's ability to travel. Kopernicus mods from before KSP 1.2.2 - sorry, but the earliest KSP version for Principia is 1.2.2, and I really can't go back further than that, unless the mod does work on 1.2.2 or above. Other than that, I hope to take every single request that I can! Download - Github

I love Principia but find it too time consuming to constantly switch around to do 'orbit maintenance' when there is long term precise requirements. Real satellites have a delta-v budget, ion/rcs engine and a team of people dedicated to this. Anyone know of any mods that will maintain my n-body orbits for me (obviously only until my fuel is used up)?

Not exactly "fanart" per se, but I guess a ragecomic can count?

I lost in some kind of betting game with my friend... So I should do.... "position a satellite at the lagrange point of Laythe". Is this possible? Oh, and no other mods, debug menu, or cheats are allowed... Please, If there's anyone that can help me?

Like Principia? Want contracts utilizing Lagrange points? Now you can have them. This mod extends Contract Configurator to let you configure contracts that can make sure your within a range of distances between two celestial bodies (a parent and a child), as well as an angle between the child body's prograde vector, and the line between the vessel and the child body (useful for differentiating between L4 and L5). Download: Github View the Source Installation: Copy the GameData folder into the KSP root directory and merge them with the existing GameData folder. This will not make contracts. View the github repo on how to configure your own contracts. Feel free to make some and share them with others! Changelog:

Seeing as Principia is getting to the point where it is quite useable, it seems to be a good time to do this. The challenge is fairly straight forward. A space station has been placed in a magical square orbit around Mun. The objective is to pilot the cargo vessel, which is in low Kerbin orbit, and rendezvous with the station, using as little delta V as possible. You will need a 1.2.2 installation of KSP with a stock planetary setup, and Principia Catalan, then load this save file. https://www.dropbox.com/s/d9vbdw0wba0jkxv/rendezvous.zip Rules: No use of cheats or performance altering mods. Telemetry and visual enhancement mods are allowed. Since this is not a docking challenge, you only have to park within a 100 meter distance from the station, with a relative velocity less than 0.3 m/s. Submissions are scored based on how much delta V remains after rendezvous is complete. The Kerbals must not exit the station. Also crashing into the station to slow down is not allowed The time limit is 5 Kerbin years. This is just a technicality since I can't be certain the orbit of the station will be stable 1000 years from now. This is not a super serious challenge so extensive documentation is not really required. Just post an screenshot showing your overall approach, and one after you've completed the challenge showing how much delta V you have left. However, feel free to show your approach in greater detail if you complete the challenge with a small amount of delta V.