1. What is Mean Motion of Satellite?

Mean Motion is the angular speed required for a body to complete an orbit, assuming constant speed in circular orbit that takes same time as variable speed elliptical orbit of actual body.

2. How Does the Calculator Work?

The calculator uses the Mean Motion formula:

Where:

• \( n \) — Mean Motion (rad/s)
• \( GM_{Earth} \) — Earth's Geocentric Gravitational Constant (3.986004418 × 10¹⁴ m³/s²)
• \( a_{semi} \) — Semi Major Axis (meters)

Explanation: The formula calculates the mean angular velocity of a satellite in its orbit around Earth based on the semi-major axis of its orbit.

3. Importance of Mean Motion Calculation

Details: Mean motion is crucial for determining orbital period, predicting satellite positions, and planning satellite maneuvers and operations.

4. Using the Calculator

Tips: Enter the semi-major axis of the satellite's orbit in meters. The value must be positive and greater than Earth's radius (approximately 6,371,000 meters).

5. Frequently Asked Questions (FAQ)

Q1: What is the relationship between mean motion and orbital period?
A: Mean motion (n) is related to orbital period (T) by the formula: n = 2π/T, where T is the time for one complete orbit.

Q2: Why is GM_Earth used instead of G and M separately?
A: The product GM (gravitational constant times Earth's mass) is known with much higher precision than either value separately, making it more accurate for orbital calculations.

Q3: What are typical values for mean motion?
A: For low Earth orbit satellites, mean motion is typically around 0.001-0.002 rad/s, while geostationary satellites have a mean motion of approximately 7.292 × 10⁻⁵ rad/s.

Q4: Does this formula work for all orbit types?
A: Yes, this formula works for elliptical orbits as well as circular orbits, using the semi-major axis of the ellipse.

Q5: How does semi-major axis affect mean motion?
A: Mean motion decreases as the semi-major axis increases. Satellites in higher orbits move slower than those in lower orbits.