Sphere of influence

Earth's SOI. The Moon's orbit is also visible.

A gravitational sphere of influence (abbreviated as SOI) is how large a planet's gravitational influence reaches into space. It attracts rockets passing by it. For a rocket/celestial body to orbit around a planet, the rocket/celestial body must be inside of the sphere of influence of it. If it's a moon, that moon will have its sphere of influence of its own. The moon can have satellites of its own and have their own spheres of influence.

Except for the Sun, all celestial bodies' SOIs end at a finite point. 

The SOI system only works for three-body or greater system, plus mass of the primary body to be much greater than the mass of the secondary body.

Calculating sphere of influence radius

The formula for calculating the SOI radius of a celestial body in the game is:

$r = m \times (R \times (\mu^1 \div \mu^2)^{0.4})$

where:

• r is the SOI radius;
• m is the multiplerSOI;
• R is the orbit radius of the celestial body;
• μ¹ is the gravitational parameter of the celestial body; and
• μ² is the gravitational parameter of the parent body.

Formula for calculating gravitational parameter:

$\mu = g\times r^2$

where:

• g is the gravity of the celestial body; and
• r is the radius of the body.

SOI list

This is a list of SOI distance of bodies in the game.

Celestial body	SOI radius
Sun	Infinite (in the game) 2.56 light-years
Mercury	11,710 kilometers
Venus	64,212 kilometers
Earth	121,725.3 kilometers
Moon	4464.6 kilometers
Captured Asteroid	3083 meters
Mars	113,430 kilometers
Phobos	2440 meters
Deimos	4123 meters
Jupiter	2,933,793 kilometers
Io	798.2 kilometers
Europa	742.1 kilometers
Ganymede	1549.1 kilometers
Callisto	2394.7 kilometers