Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Orbital Motion: Circular and Elliptical

Description

This lecture covers the concepts of circular and elliptical orbits, including orbital period, velocity, energy, angular momentum, and the variation of the flight path angle. The instructor explains the characteristics of elliptical orbits such as apoapsis, periapsis, and the line of Apsides.

In MOOC

Space Mission Design and Operations

Official source

Related concepts (32)

Orbit

In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a planet, moon, asteroid, or Lagrange point. Normally, orbit refers to a regularly repeating trajectory, although it may also refer to a non-repeating trajectory.

Elliptic orbit

In astrodynamics or celestial mechanics, an elliptic orbit or elliptical orbit is a Kepler orbit with an eccentricity of less than 1; this includes the special case of a circular orbit, with eccentricity equal to 0. In a stricter sense, it is a Kepler orbit with the eccentricity greater than 0 and less than 1 (thus excluding the circular orbit). In a wider sense, it is a Kepler orbit with negative energy. This includes the radial elliptic orbit, with eccentricity equal to 1.

Orbital speed

In gravitationally bound systems, the orbital speed of an astronomical body or object (e.g. planet, moon, artificial satellite, spacecraft, or star) is the speed at which it orbits around either the barycenter or, if one body is much more massive than the other bodies of the system combined, its speed relative to the center of mass of the most massive body. The term can be used to refer to either the mean orbital speed (i.e. the average speed over an entire orbit) or its instantaneous speed at a particular point in its orbit.

Orbital mechanics

Orbital mechanics or astrodynamics is the application of ballistics and celestial mechanics to the practical problems concerning the motion of rockets and other spacecraft. The motion of these objects is usually calculated from Newton's laws of motion and the law of universal gravitation. Orbital mechanics is a core discipline within space-mission design and control. Celestial mechanics treats more broadly the orbital dynamics of systems under the influence of gravity, including both spacecraft and natural astronomical bodies such as star systems, planets, moons, and comets.

Orbital elements

Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit. There are many different ways to mathematically describe the same orbit, but certain schemes, each consisting of a set of six parameters, are commonly used in astronomy and orbital mechanics. A real orbit and its elements change over time due to gravitational perturbations by other objects and the effects of general relativity.

Related lectures (49)

Elliptical Orbits: Examples and Formulas MOOC: Space Mission Design and Operations

Covers examples and formulas related to elliptical orbits and how to determine parameters of an elliptical orbit using known points.

Kepler Laws: Introduction to Astrophysics MOOC: Introduction to Astrophysics

Covers the Kepler Laws, orbital motion, reduced mass, and orbital periods.

Hohmann Transfer: Small AV MOOC: Space Mission Design and Operations

Discusses the Hohmann transfer for small AV and orbital parameters at different altitudes.

Stellar Orbits in Axisymmetric Potentials

Explores the dynamics of stellar orbits in axisymmetric potentials, focusing on nearly circular orbits and different types of motion.

Catch up rate between orbits MOOC: Space Mission Design and Operations