Principia:SSO Calculator(Stock,RSS)

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Initial Page

Introduce

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

1. The newly generated StockPlanet_GravityModels.cfg file requires support from Kopernicus.
2. If you want to enter a sun-synchronous orbit, you must have the support of Principia.

Tutorial

1. Open SSOCalculator.exe

2. First select the System, then select the corresponding Planet.

   • If you choose RealSolarSystem, then you only need to enter the Altitude (excluding the planet radius) and Eccentricity, and click Calculate to get the Satellite Orbital Parameters want. (SMA = Semi-major Axis)

     

     Example of Earth’s sun-synchronous orbit

   • If you choose Stock, then you need to enter the Altitude (excluding the planet radius) and Eccentricity, and j2.
     ( Note: The j2 term can refer to the j2 parameter of a planet similar to your choice in sol_gravity_model.proto.txt.)
     After clicking Calculate, you will get the Satellite Orbital Parameters want. (SMA = Semi-major Axis)

     

     Example of Earth’s sun-synchronous orbit

3. In the Stock environment, once the orbit parameters are correctly generated, you will find that the Generate Configuration File button is enabled. Next, you only need to click it to generate the StockPlanet_GravityModels.cfg file. Then put it anywhere in GameData.
   (Note:The generated file is in the current directory.)

Configuration generation successful case

GameData content

1. The Clear button is for one-click clearing of the Altitude, Eccentricity, and j2 parameters.

To-Do List

1. Considering adding a button, the purpose of this button is to append the content of the generated configuration.

Warning

1. This tool does not take into account whether the orbit composed of the altitude and eccentricity you entered is below a safe value, and you need to verify it in the game.

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.