Mechanics

Geosynchronous Orbit Radius

r=GMT24π23r = \sqrt[3]{\frac{GMT^2}{4\pi^2}}

Radius of an orbit with a specific period. For geosynchronous orbit, T equals the planet's rotation period.

Variables

r
Orbital radius
Distance from center of planet
Allowed values: greater than 0
m
G
Gravitational constant
6.674×10⁻¹¹
In SI units: m³/(kg·s²)
Allowed values: greater than 0
N·m²/kg²
M
Planet mass
Mass of planet
Allowed values: greater than 0
kg
T
Orbital period
Time for one orbit (24 hrs for Earth geosync)
Allowed values: greater than 0
s

Derivation

From T = 2π√(r³/GM), solve for r: r³ = GMT²/(4π²), so r = (GMT²/4π²)^(1/3).

Your notes

0/5000

Constants in this formula

G
6.674 30 × 10⁻¹¹ ± 0.000 15 × 10⁻¹¹. Measured (CODATA 2018).
N·m²/kg²

Check value

Round inputs run through this page's calculator, with each constant at its tabulated value. Use it to test your own working or a rearranged form. It is a test case, not a real-world example.

  • G = 6.674 30 × 10⁻¹¹ N·m²/kg² (Gravitational constant)
  • M = 2 kg (Planet mass)
  • T = 3 s (Orbital period)

Result: r = 0.0003122 m

Other mechanics formulas with the same quantities

Where this formula is listed

Common questions

What is the Geosynchronous Orbit Radius formula?

Geosynchronous Orbit Radius is written r = ∛(GMT²/(4π²)). Radius of an orbit with a specific period. For geosynchronous orbit, T equals the planet's rotation period. It belongs to Mechanics, under Gravitation.

What are the units in r = ∛(GMT²/(4π²))?

In SI units, r is orbital radius, measured in m; G is gravitational constant, measured in m³/(kg·s²); M is planet mass, measured in kg; T is orbital period, measured in s.

How is the Geosynchronous Orbit Radius formula derived?

From T = 2π√(r³/GM), solve for r: r³ = GMT²/(4π²), so r = (GMT²/4π²)^(1/3). The result is r = ∛(GMT²/(4π²)).