Mean Longitude

Information about Mean Longitude

In astrodynamics or celestial dynamics mean longitude is the longitude at which an orbiting body could be found if its orbit were circular and its inclination were zero. The mean longitude changes at a constant rate over time. The only times when it is equal to the true longitude are at periapsis and apoapsis.

Calculation

The mean longitude $\text{[math]}$ can be calculated as follows:

$\text{[math]}$

where:

$\text{[math]}$ is orbit's mean anomaly,
$\text{[math]}$ is longitude of the orbit's periapsis,
$\text{[math]}$ is the longitude of ascending node and
$\text{[math]}$ is the argument of periapsis.

• • [ e] Orbits
Orbit types	Box orbit • Circular orbit • Ecliptic orbit • Elliptic orbit • Highly Elliptical Orbit • Graveyard orbit • Hyperbolic trajectory • Inclined orbit • Osculating orbit • Parabolic trajectory • Capture orbit • Escape orbit • Semi-synchronous orbit • Subsynchronous orbit • Synchronous orbit • Parking orbit
Earth-centered orbits	Geosynchronous orbit • Geostationary orbit • Sun-synchronous orbit • Low Earth orbit • Medium Earth Orbit • Molniya orbit • Near equatorial orbit • Orbit of the Moon • Polar orbit • Tundra orbit
Other orbits	Areosynchronous orbit • Areostationary orbit • Halo orbit • Lissajous orbit • Lunar orbit • Heliocentric orbit • Heliosynchronous orbit
Orbital elements	Inclination ( $\text{[math]}$ ) • Longitude of the ascending node ( $\text{[math]}$ ) • Eccentricity ( $\text{[math]}$ ) • Argument of periapsis ( $\text{[math]}$ ) • Semi-major axis ( $\text{[math]}$ ) • Mean anomaly at epoch ( $\text{[math]}$ )
Other orbital parameters	True anomaly ( $\text{[math]}$ ) • Semi-minor axis ( $\text{[math]}$ ) • Linear eccentricity ( $\text{[math]}$ ) • Eccentric anomaly ( $\text{[math]}$ ) • Mean longitude ( $\text{[math]}$ ) • True longitude ( $\text{[math]}$ ) • Orbital period ( $\text{[math]}$ )
Orbital maneuvers	Bi-elliptic transfer • Geostationary transfer orbit • Gravitational slingshot • Hohmann transfer orbit • Orbital inclination change • Orbit phasing • Space rendezvous
Other orbital mechanics topics	Apsis • Celestial coordinate system • Delta-v budget • Epoch • Ephemeris • Equatorial coordinate system • Gravity turn • Ground track • Interplanetary Transport Network • Kepler's laws of planetary motion • Lagrangian point • List of orbits • n-body problem • Orbit equation • Orbital state vectors • Perturbation • Retrograde and direct motion • Specific orbital energy • Specific relative angular momentum • The Oberth effect

Orbital mechanics or astrodynamics is the study of the motion of rockets and other spacecraft. The motion of these objects is determined by Newton's laws of motion and the law of universal gravitation.
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Celestial mechanics is a division of astronomy dealing with the motions and gravitational effects of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data.
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equator divides the planet into a Northern Hemisphere and a Southern Hemisphere, and has a latitude of 0. Longitude is the east-west geographic coordinate measurement most commonly utilized in cartography and global navigation.
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For other meanings of the term "orbit", see orbit (disambiguation)

In astrodynamics or celestial mechanics a circular orbit is an elliptic orbit with the eccentricity equal to 0.
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For the science fiction novella by William Shunn, see .

Inclination in general is the angle between a reference plane and another plane or axis of direction.
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In astrodynamics true longitude is the longitude at which an orbiting body could actually be found if its inclination were zero. Together with the inclination and the ascending node, the true longitude can tell us the precise direction from the central object at which the body
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In the study of orbital dynamics the mean anomaly of an orbiting body is the angle the body would have traveled about the center of the orbit's auxiliary circle. Unlike other measures of anomaly, the mean anomaly grows linearly with time.
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longitude of the ascending node (☊ or Ω) is one of the orbital elements used to specify the orbit of an object in space. It is the angle from a reference direction, called the origin of longitude
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The argument of periapsis (ω) is the orbital element describing the angle of an orbiting body's periapsis (the point of closest approach to the central body), relative to its ascending node (the point where the body crosses the plane of reference from South to North).
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ORBit is a CORBA compliant Object Request Broker (ORB). The current version is called ORBit2 and is compliant with CORBA version 2.4. It is developed under the GPL license and is used as middleware for the GNOME project.
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In stellar dynamics a box orbit refers to a particular type of orbit which can be seen in triaxial systems, that is, systems which do not possess a symmetry around any of its axes.
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For other meanings of the term "orbit", see orbit (disambiguation)

In astrodynamics or celestial mechanics a circular orbit is an elliptic orbit with the eccentricity equal to 0.
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A non-inclined orbit is an orbit which is contained in the plane of reference. It therefore has inclination equal to zero. If the plane of reference is the equator, these orbits are called equatorial; if the plane of reference is the ecliptic, they are called ecliptic.
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elliptic orbit can be computed from the Vis-viva equation as:

where:

is standard gravitational parameter,
is radial distance of orbiting body from central body,
is length of semi-major axis.

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Highly Elliptical Orbit (HEO) is an elliptic orbit characterized by a relatively low-altitude perigee and an extremely high-altitude apogee. These extremely elongated orbits can have the advantage of long dwell times at a point in the sky during the approach to and descent from
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A graveyard orbit, also called a supersynchronous orbit, junk orbit or disposal orbit, is an orbit significantly above synchronous orbit where spacecraft are intentionally placed at the end of their operational life.
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In astrodynamics or celestial mechanics a hyperbolic trajectory is an orbit with the eccentricity greater than 1. Under standard assumptions a body traveling along this trajectory will coast to infinity, arriving there with hyperbolic excess velocity relative to the central body.
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A satellite is said to occupy an inclined orbit around the Earth if the orbit exhibits an angle other than zero degrees with the equatorial plane. This angle is called the orbit's inclination.
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In astronomy, and in particular in astrodynamics, the osculating orbit of an object in space is the gravitational Keplerian orbit about a central body that it would have if other perturbations were not present.
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In astrodynamics or celestial mechanics a parabolic trajectory is an orbit with the eccentricity equal to 1. When moving away from the source it is called an escape orbit, otherwise a capture orbit.
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A capture orbit is a reverse escape orbit. It is a parabolic orbit with as special case a straight line in the direction of the center of the central body. If it intersects the central body or its atmosphere the object will crash into the central body or there will be atmospheric
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An escape orbit (also known as C3 = 0 orbit) is a high-energy parabolic orbit around the central body. A body in this orbit has at each position the escape velocity with respect to this central body, for this position.
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Semi-Synchronous Orbit (SSO): An orbit with approximately a 12-hour period. A circular SSO is at an altitude of approximately 20,200 km.^[1]

References

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A subsynchronous orbit refers to the orbit of a satellite that is nearer the planet than it would be if it were in synchronous orbit, i.e. the orbital period is less than the sidereal day of the planet.
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A synchronous orbit is an orbit in which an orbiting body (usually a satellite) has a period equal to the average rotational period of the body being orbited (usually a planet), and in the same direction of rotation as that body.
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A parking orbit is a temporary orbit used during the launch of a satellite or other space probe. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory.
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A geocentric orbit is an orbit of any object orbiting the Earth, such as the Moon or artificial satellites. Currently there are approximately 2465 artificial satellites orbiting the Earth and 6216 pieces of space debris as tracked by the Goddard Space Flight Center.
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A geosynchronous orbit is an orbit around the Earth with an orbital period matching the Earth's sidereal rotation period. This synchronization means that for an observer at a fixed location on Earth, a satellite in a geosynchronous orbit returns to exactly the same place in the sky
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Mean Longitude

Information about Mean Longitude

Calculation

See also

References