1. What is the Perigee Radius?

Perigee Radius refers to the distance between the center of the Earth and the point in a satellite's orbit that is closest to the Earth's surface. It is a crucial parameter in orbital mechanics and satellite operations.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( r_{perigee} \) — Perigee Radius (m)
• \( a_{orbit} \) — Major Orbital Axis (m)
• \( e \) — Eccentricity (unitless)

Explanation: The formula calculates the closest approach distance of a satellite to the Earth based on the orbital characteristics.

3. Importance of Perigee Radius Calculation

Details: Accurate perigee radius calculation is essential for satellite orbit planning, collision avoidance, and ensuring proper orbital parameters for communication and observation satellites.

4. Using the Calculator

Tips: Enter major orbital axis in meters and eccentricity (value between 0 and 1). Both values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between perigee and perigee radius?
A: Perigee refers to the point of closest approach, while perigee radius is the actual distance measurement from the center of the Earth to that point.

Q2: Can eccentricity be exactly 1?
A: No, eccentricity values range from 0 (circular orbit) to values approaching 1 (highly elliptical orbits), but cannot be exactly 1 for closed orbits.

Q3: What are typical values for major orbital axis?
A: For Earth satellites, major orbital axis typically ranges from about 6,600 km (low Earth orbit) to 42,000 km (geostationary orbit).

Q4: How does perigee radius affect satellite operations?
A: Lower perigee radii result in higher orbital speeds and may require more frequent orbital maintenance due to atmospheric drag.

Q5: Is this formula applicable to all orbital types?
A: This formula applies specifically to elliptical orbits around Earth. Different formulas are used for parabolic or hyperbolic trajectories.