Orbit nomenclature

Mostly for future reference:

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From

http://www.aero.org/publications/chao/index.html

Applied Orbit Perturbation and Maintenance
Chia-Chun "George" Chao
The Aerospace Press
ISBN 1-884989-17-9

The following definitions of various orbit types are useful for
discussing concepts related to the orbits of Earth satellites.

ACE (apogee at constant time-of-day equatorial) orbit: An elliptical
orbit that lies in Earth's equatorial plane with a sun-pointing apogee.
To satisfy the sun-pointing property, the secular rate of the apsidal
rotation in the inertial reference frame must equal the rate of the
right ascension of the sun.

frozen orbit: An Earth satellite orbit whose mean eccentricity and
argument of perigee remain constant, such as NASA's Topex mission
orbit.

GEO: Geostationary or geosynchronous orbit; one with an altitude of
about 35,786 km. Its orbital mean motion equals the Earth's rotation
rate. A geostationary satellite requires both longitude and latitude
control, while a geosynchronous satellite requires only longitude
stationkeeping. A geostationary satellite appears stationary to a
ground observer. Most communication satellites, such as Intelsat and
PanAmSat, are geostationary.

GTO: Geostationary transfer orbit; an elliptical orbit that completes a
Hohmann and plane-change transfer from a low, circular parking orbit to
a geosynchronous drift orbit. A geosynchronous or geostationary drift
orbit is a circular orbit with a mean altitude either higher or lower
than the stationary altitude required for a newly launched satellite to
move to its desired longitude, usually at a rate of 3 deg/day,
equivalent to an altitude of 234 km above or below GEO altitude.

HEO: Highly elliptical orbit; one with eccentricity larger than 0.5.

LEO: Low Earth orbit; one with altitude less than 1000 km, the level
where atmospheric drag becomes significant.

Magic orbit: An orbit that has a period of about 3 hours, an
inclination of 116.6 deg, and a nonzero eccentricity. Its semimajor
axis and eccentricity values satisfy conditions for both
sun-synchronous and frozen orbits.

MEO: Medium Earth orbit; one with an altitude between 1000 km and
35,286 km (500 km less than geostationary distance), such as the orbits
of Galileo and GLONASS.

Molniya orbit: A highly elliptical orbit that has a 12-hour period and
an inclination near the critical value (63.4 deg). It has an argument
of perigee of 270 deg, and its ground traces repeat every other
revolution.

sun-synchronous orbit: A satellite orbit whose nodal rate equals the
angular rate of the mean sun, or one for which the local time of every
ascending node crossing remains the same throughout the year, such as
the weather satellite orbits.

supersynchronous orbit: A circular or nearly circular orbit with an
altitude higher than that of the GEO orbit (about 35,786 km), such as
the GEO disposal orbits.

Tundra orbit: An orbit with a 24-hour period, 30 to 70 deg inclination,
and eccentricity from 0.13 to 0.5. Its primary purpose is to ensure
good polar coverage in situations where regular GEO orbits cannot do
so.

Allen Thomson wrote:
Mostly for future reference:


sci.space.online-dictionary?

Thanks for posting this, BTW.

/dps