1. What is Orbital Eccentricity?

Orbital eccentricity is a parameter that determines the amount by which an orbit around another body deviates from a perfect circle. It's a dimensionless parameter that ranges from 0 (perfect circle) to 1 (parabolic trajectory).

2. How Does the Calculator Work?

The calculator uses the orbital eccentricity formula:

Where:

• \( r_a \) — Apogee, the farthest point in an orbit from the center of mass (km)
• \( r_p \) — Perigee, the closest point in an orbit to the center of mass (km)
• \( e \) — Orbital eccentricity (unitless)

Explanation: The formula calculates how elongated an orbit is by comparing the difference between apogee and perigee to their sum.

3. Importance of Eccentricity Calculation

Details: Eccentricity is crucial in orbital mechanics for determining orbital characteristics, predicting satellite behavior, planning orbital maneuvers, and understanding celestial mechanics.

4. Using the Calculator

Tips: Enter apogee and perigee distances in kilometers. Both values must be positive, and apogee must be greater than or equal to perigee.

5. Frequently Asked Questions (FAQ)

Q1: What does an eccentricity of 0 mean?
A: An eccentricity of 0 indicates a perfectly circular orbit where the distance from the center remains constant.

Q2: What is considered a high eccentricity value?
A: Values above 0.5 are generally considered highly eccentric. Earth's orbit has an eccentricity of about 0.0167, which is nearly circular.

Q3: Can eccentricity be greater than 1?
A: For closed orbits (ellipses), eccentricity ranges from 0 to 1. Values greater than 1 indicate open trajectories (hyperbolas).

Q4: How does eccentricity affect orbital period?
A: For a given semi-major axis, eccentricity doesn't affect orbital period (Kepler's third law), but it does affect orbital velocity.

Q5: Why is eccentricity important for satellite operations?
A: Eccentricity affects communication windows, solar exposure, thermal management, and fuel requirements for station-keeping.