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Satellite Gravity-Gradient Stabilization Torque Calculator

The inverse-square gravitational field exerts slightly stronger attraction on the lower parts of an orbiting satellite than on the upper parts.

Altitude above mean Earth surface.

Principal transverse moment of inertia.

Principal yaw/nadir moment of inertia.

Angle between minimum inertia axis and local vertical.

Calculated Result
121.67 µN·m

Gravity-Gradient Restoring Torque

Torque in N·m

1.217e-4 N·m

Inertia Asymmetry |Ix - Iz|

170.0 kg·m²

Mean Motion (n)

1.083 mrad/s

Calculation Breakdown

  1. Torque FormulaT_gg = (3·μ / 2r³) · |I_x - I_z| · sin(2θ)
  2. Evaluation3·398600000000000 / (2·r³) · 170 · sin(24°) = 121.67 µN·m

What Is the Satellite Gravity-Gradient Stabilization Torque Calculator?

Gravity-gradient torque is an environmental torque arising from the non-uniform gravitational field across an extended satellite body.

How Does the Satellite Gravity-Gradient Stabilization Torque Calculator Work?

Integrates differential gravitational force across the mass distribution of the spacecraft.

Satellite Gravity-Gradient Stabilization Torque Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

T_{ ext{gg}} = rac{3 mu}{2 r^3} |I_x - I_z| sin(2 heta)

First-order differential gravitational torque on an asymmetric rigid body.

How to Use the Satellite Gravity-Gradient Stabilization Torque Calculator

  1. Input orbit altitude, principal moments of inertia Ix and Iz, and angular deviation from nadir.

Step-by-Step Example Calculation

Earth-Pointing LEO CubeSat/SmallSat

Input Values:

orbitAltitudeKm:600
pitchInertiaIxKgM2:250
yawInertiaIzKgM2:80
pitchDeviationAngleDeg:12
Worked Steps: Restoring torque T_gg = 60.1 µN·m with orbital mean motion n = 1.08 mrad/s.

Understanding Your Result

Shows stabilizing restoring torque in micro-Newton-meters (µN·m) and orbital mean motion.

Factors That Affect the Result

  • Torque decays rapidly with distance as 1/r^3; most pronounced in Low Earth Orbit (LEO).

When Should You Use This Calculator?

  • Passive attitude stabilization design (using gravity-gradient deployable booms) and reaction wheel momentum dumping budget.

Assumptions & Limitations

  • Assumes circular orbit around a spherical central body; rigid body mechanics.

Frequently Asked Questions

Calculation Accuracy & Reference Note

Standard spacecraft attitude dynamics perturbation model.

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