A supersynchronous orbit is either an

orbit In celestial mechanics, an orbit 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 ...

with a period greater than that of a synchronous orbit, or just an orbit whose apoapsis (apogee in the case of the Earth) is higher than that of a synchronous orbit. A synchronous orbit has a period equal to the rotational period of the body which contains the

barycenter In astronomy, the barycenter (or barycentre; ) is the center of mass of two or more bodies that orbit one another and is the point about which the bodies orbit. A barycenter is a dynamical point, not a physical object. It is an important con ...

of the orbit.

Geocentric supersynchronous orbits

One particular supersynchronous orbital regime of significant

economic value In economics, economic value is a measure of the benefit provided by a good or service to an economic agent. It is generally measured through units of currency, and the interpretation is therefore "what is the maximum amount of money a speci ...

to Earth commerce is a band of near-circular

Geocentric In astronomy, the geocentric model (also known as geocentrism, often exemplified specifically by the Ptolemaic system) is a superseded description of the Universe with Earth at the center. Under most geocentric models, the Sun, Moon, stars, an ...

orbits beyond the geosynchronous belt—with

perigee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any el ...

altitude above , approximately above synchronous altitude —called the geo graveyard belt. The geo graveyard belt orbital regime is valuable as a storage and disposal location for

derelict satellite Space debris (also known as space junk, space pollution, space waste, space trash, or space garbage) are defunct human-made objects in space—principally in Earth orbit—which no longer serve a useful function. These include derelict spacec ...

space debris Space debris (also known as space junk, space pollution, space waste, space trash, or space garbage) are defunct human-made objects in space—principally in Earth orbit—which no longer serve a useful function. These include derelict spacec ...

after their useful economic life is completed as geosynchronous communication satellites. Artificial satellites are left in space because the economic cost of removing the debris would be high, and current

public policy Public policy is an institutionalized proposal or a decided set of elements like laws, regulations, guidelines, and actions to solve or address relevant and real-world problems, guided by a conception and often implemented by programs. Public ...

does not require nor incentivize rapid removal by the party that first inserted the debris in

outer space Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, pred ...

and thus created a

negative externality In economics, an externality or external cost is an indirect cost or benefit to an uninvolved third party that arises as an effect of another party's (or parties') activity. Externalities can be considered as unpriced goods involved in either co ...

for others—a placing of the cost onto them. One public policy proposal to deal with growing space debris is a "one-up/one-down"

launch license The Office of Commercial Space Transportation (generally referred to as FAA/AST or simply AST) is the branch of the United States Federal Aviation Administration (FAA) that approves any commercial rocket launch operations — that is, any laun ...

policy for Earth orbits. Launch vehicle operators would have to pay the cost of debris mitigation. They would need to build the capability into their launch vehicle-robotic capture, navigation, mission duration extension, and substantial additional propellant – to be able to rendezvous with, capture and deorbit an existing derelict satellite from approximately the same orbital plane.Frank Zegler and Bernard Kutter
"Evolving to a Depot-Based Space Transportation Architecture"
, AIAA SPACE 2010 Conference & Exposition, 30 August-2 September 2010, AIAA 2010–8638. An additional common use of supersynchronous orbits are for the launch and transfer orbit trajectory of new commsats intended for

geosynchronous orbit A geosynchronous orbit (sometimes abbreviated GSO) is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds (one sidereal day). The synchronization of rotation and orbita ...

s. In this approach, the

launch vehicle A launch vehicle or carrier rocket is a rocket designed to carry a payload ( spacecraft or satellites) from the Earth's surface to outer space. Most launch vehicles operate from a launch pads, supported by a launch control center and sys ...

places the satellite into a ''supersynchronous'' elliptical transfer orbit, an orbit with a somewhat larger

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any el ...

than the more typical

geostationary transfer orbit A geosynchronous transfer orbit or geostationary transfer orbit (GTO) is a type of geocentric orbit. Satellites that are destined for geosynchronous (GSO) or geostationary orbit (GEO) are (almost) always put into a GTO as an intermediate step ...

(GTO) typically used for communication satellites. Such an orbit is used because a small change in inclination at a lower altitude requires much more energy than the same change at a higher altitude. Thus is it sometimes optimal to use spacecraft propulsion to change the inclination at a higher-than-desired apogee, then lower the apogee to the desired altitude—resulting in a lower total expenditure of propellant by the satellite's kick motor. This technique was used, for example, on the launch and transfer orbit injection of the first two

SpaceX Space Exploration Technologies Corp. (SpaceX) is an American spacecraft manufacturer, launcher, and a satellite communications corporation headquartered in Hawthorne, California. It was founded in 2002 by Elon Musk with the stated goal o ...

Falcon 9 v1.1 GTO launches in December 2013 and January 2014, SES-8 and Thaicom 6 (-

), respectively. In both cases, the satellite owner uses the

propulsion Propulsion is the generation of force by any combination of pushing or pulling to modify the translational motion of an object, which is typically a rigid body (or an articulated rigid body) but may also concern a fluid. The term is derived f ...

built into the satellite to reduce the apogee and circularize the orbit to a

geostationary orbit A geostationary orbit, also referred to as a geosynchronous equatorial orbit''Geostationary orbit'' and ''Geosynchronous (equatorial) orbit'' are used somewhat interchangeably in sources. (GEO), is a circular geosynchronous orbit in altitu ...

. This has also been a common practice by ULA, including the WGS communications satellite constellation. This technique was also used on the launch of

SES-14 SES-14 is a geostationary communications satellite operated by SES S.A. at 47.5° West, replaces NSS-806, and designed and manufactured by Airbus Defence and Space. The satellite launched on 25 January 2018 at 22:20 UTC along with the Global ...

and Al Yah 3 during Ariane 5 flight VA241. However, due to launch crew error resulting in anomaly and a deviation of the trajectory, the satellites were not inserted into the intended orbit, causing a reschedule of their maneuvering plan.

Non-Geocentric supersynchronous orbits

Most natural satellites in the

Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...

are in supersynchronous orbits. The

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

is in a supersynchronous orbit of

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's sur ...

, orbiting more slowly than the 24-hour rotational period of Earth. The inner of the two Martian moons, Phobos, is in a

subsynchronous orbit A subsynchronous orbit is an 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. Technical considerations An Earth satellite that i ...

of Mars with an orbital period of only 0.32 days. The outer moon

Deimos Deimos, a Greek word for ''dread'', may refer to: * Deimos (deity), one of the sons of Ares and Aphrodite in Greek mythology * Deimos (moon), the smaller and outermost of Mars' two natural satellites * Elecnor Deimos, a Spanish aerospace company * ...

is in supersynchronous orbit around

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

. The

Mars Orbiter Mission The Mars Orbiter Mission (MOM), also called ''Mangalyaan'', was a space probe orbiting Mars since 24 September 2014. It was launched on 5 November 2013 by the Indian Space Research Organisation (ISRO). It was India's first interplanetary mis ...

—currently orbiting Mars—is placed into highly elliptical supersynchronous orbit around Mars, with a period of 76.7 hours and a planned periapsis of and apoapsis of .

References

{{Reflist, 30em Astrodynamics Orbits

Geocentric supersynchronous orbits

Non-Geocentric supersynchronous orbits

See also

References