Section 3: Orbital Mechanics & Maneuvers

Kepler’s Laws & Orbit Shape

Orbits are governed by gravity and are elliptical.

Orbital Element: Semi-major axis (a)

Defines the size of the orbit.

Orbital Element: Eccentricity (e)

Defines the shape of the orbit (circular vs. elliptical).

Orbital Element: Inclination (i)

Defines the orientation of the orbit relative to the Earth's equator.

Orbital Element: Argument of Perigee (ω)

Defines the location of the orbit's low point (perigee) relative to the Earth's surface.

Orbital Element: Right Ascension of the Ascending Node (Ω)

Defines the location of the ascending node relative to the equatorial plane.

Orbital Element: True/Mean Anomaly (ν)

Defines the satellite's specific position within the orbit at a given time.

Common Orbit Types (List)

LEO, MEO, GEO, Polar, and Sun-synchronous.

Molniya Orbit

A highly elliptical, high-inclination orbit utilized for communication at high latitudes.

Hohmann Transfer

The primary method used to move a spacecraft between two circular orbits of different radii.

Gravity Assists

Using a planet's gravity to change the path and speed of a spacecraft.

Escape Velocity

The speed needed to break free from a gravitational field.

Sphere of Influence (SOI)

The region around a celestial body where its gravity is the primary influence on an object.