Sphere of Influence Calculator

Property to Calculate:

Radius of the sphere of influence (r):

Semi-major axis (a):

Mass of the smaller body (m):

Mass of the larger body (M):

How This Is Calculated

$$ r_{SOI} = a \left( \frac{m}{M} \right)^{\frac{2}{5}} $$ where:

r_SOI = Radius of the sphere of influence (m)

a = Semi-major axis (m)

m = Mass of the smaller body (kg)

M = Mass of the larger body (kg)

Assumptions

The system is treated as a two-body problem.
Central body is spherically symmetric.
Orbit follows Kepler's laws of motion.
Both masses are treated as point masses.
Gravitational fields are time-invarient.

Related Calculators

Orbital Period

Orbital Period for Circular Orbits

Orbital Velocity

Radius from True Anomaly

Specific Orbital Energy