Supersynchronous orbit

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A supersynchronous orbit is either an orbit 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 of the orbit.

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Geocentric supersynchronous orbits

One particular supersynchronous orbital regime of significant economic value to Earth commerce is a band of near-circular Geocentric orbits beyond the geosynchronous belt—with perigee altitude above 36,100 kilometres (22,400 mi), approximately 300 kilometres (190 mi) above synchronous altitude [1] —called the geo graveyard belt. [2]

The geo graveyard belt orbital regime is valuable as a storage and disposal location for derelict satellite space debris after their useful economic life is completed as geosynchronous communication satellites. [2] Artificial satellites are left in space because the economic cost of removing the debris would be high, and current public policy does not require nor incentivize rapid removal by the party that first inserted the debris in outer space and thus created a negative externality 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 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. [3]

An additional common use of supersynchronous orbits are for the launch and transfer orbit trajectory of new commsats intended for geosynchronous orbits. In this approach, the launch vehicle places the satellite into a supersynchronous elliptical transfer orbit, [4] an orbit with a somewhat larger apogee than the more typical geostationary transfer orbit (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. [5]

This technique was used, for example, on the launch and transfer orbit injection of the first two SpaceX Falcon 9 v1.1 GTO launches in December 2013 and January 2014, SES-8 [4] and Thaicom 6 (90,000 kilometers (56,000 mi)-apogee), [5] respectively. In both cases, the satellite owner uses the propulsion built into the satellite to reduce the apogee and circularize the orbit to a geostationary orbit. 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 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. [6]

Non-Geocentric supersynchronous orbits

The Martian moons Phobos and Deimos are in subsynchronous and supersynchronous orbits respectively. Phobos is orbiting Mars faster than the rotation of Mars itself. Orbits of Phobos and Deimos.gif
The Martian moons Phobos and Deimos are in subsynchronous and supersynchronous orbits respectively. Phobos is orbiting Mars faster than the rotation of Mars itself.

Most natural satellites in the Solar System are in supersynchronous orbits. The Moon is in a supersynchronous orbit of Earth, orbiting more slowly than the 24-hour rotational period of Earth. The inner of the two Martian moons, Phobos, is in a subsynchronous orbit of Mars with an orbital period of only 0.32 days. [7] The outer moon Deimos is in supersynchronous orbit around Mars. [7]

The Mars Orbiter Mission—currently orbiting Mars—is placed into highly elliptical supersynchronous orbit around Mars, with a period of 76.7 hours and a planned periapsis of 365 km (227 mi) and apoapsis of 70,000 km (43,000 mi). [8]

See also

Related Research Articles

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<span class="mw-page-title-main">Geosynchronous orbit</span> Orbit keeping the satellite at a fixed longitude above the equator

A geosynchronous orbit is an Earth-centered orbit with an orbital period that matches Earth's rotation on its axis, 23 hours, 56 minutes, and 4 seconds. The synchronization of rotation and orbital period means that, for an observer on Earth's surface, an object in geosynchronous orbit returns to exactly the same position in the sky after a period of one sidereal day. Over the course of a day, the object's position in the sky may remain still or trace out a path, typically in a figure-8 form, whose precise characteristics depend on the orbit's inclination and eccentricity. A circular geosynchronous orbit has a constant altitude of 35,786 km (22,236 mi).

<span class="mw-page-title-main">Geostationary orbit</span> Circular orbit above Earths Equator and following the direction of Earths rotation

A geostationary orbit, also referred to as a geosynchronous equatorial orbit (GEO), is a circular geosynchronous orbit 35,786 km (22,236 mi) in altitude above Earth's equator and following the direction of Earth's rotation.

A synchronous orbit is an orbit in which an orbiting body has a period equal to the average rotational period of the body being orbited, and in the same direction of rotation as that body.

<span class="mw-page-title-main">Low Earth orbit</span> Orbit around Earth with an altitude between 160 and 2,000 kilometres (99 and 1,243 mi)

A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never more than about one-third of the radius of Earth.

<span class="mw-page-title-main">Geostationary transfer orbit</span> Hohmann transfer orbit used to reach geosynchronous or geostationary 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 for reaching their final orbit.

A geocentric orbit or Earth orbit involves any object orbiting Earth, such as the Moon or artificial satellites. In 1997, NASA estimated there were approximately 2,465 artificial satellite payloads orbiting Earth and 6,216 pieces of space debris as tracked by the Goddard Space Flight Center. More than 16,291 objects previously launched have undergone orbital decay and entered Earth's atmosphere.

The areosynchronous orbits (ASO) are the synchronous orbits for artificial satellites around the planet Mars. They are the martian equivalent of the geosynchronous orbits (GSO) on the Earth. The prefix areo- derives from Ares, the ancient Greek god of war and counterpart to the Roman god Mars, with whom the planet was identified. The modern Greek word for Mars is Άρης (Áris).

<span class="mw-page-title-main">Graveyard orbit</span> Planned spacecraft end-of-life orbit

A graveyard orbit, also called a junk orbit or disposal orbit, is an orbit that lies away from common operational orbits. One significant graveyard orbit is a supersynchronous orbit well beyond geosynchronous orbit. Some satellites are moved into such orbits at the end of their operational life to reduce the probability of colliding with operational spacecraft and generating space debris.

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GSAT-1 was an experimental communications satellite launched aboard the maiden flight of the GSLV rocket. The spacecraft was equipped with instrumentation to test Pulse-code modulation (PCM) transmitting on S-band frequencies and transponders operating in the C-band. The spacecraft was unable to complete its mission after a launch failure left it in a lower than planned orbit and propulsion issues prevented the satellite from correcting this via its own maneuvering system.

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.

A parking orbit is a temporary orbit used during the launch of a spacecraft. A launch vehicle boosts into the parking orbit, then coasts for a while, then fires again to enter the final desired trajectory. The alternative to a parking orbit is direct injection, where the rocket fires continuously until its fuel is exhausted, ending with the payload on the final trajectory. The technology was first used by the Soviet Venera 1 mission to Venus.

<span class="mw-page-title-main">Apogee kick motor</span> Type of rocket motor

An apogee kick motor (AKM) is a rocket motor that is regularly employed on artificial satellites to provide the final impulse to change the trajectory from the transfer orbit into its final orbit. For a satellite launched from the Earth, the rocket firing is done at the highest point of the transfer orbit, known as the apogee.

Thaicom 5 was a geostationary communications satellite operated by Thaicom. It was used to provide communications services to Asia, Africa, Middle East, Americas, Europe and Australia.

<span class="mw-page-title-main">Thaicom 6</span> Thai satellite

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<span class="mw-page-title-main">SES-9</span>

SES-9 is a geostationary communications satellite operated by SES S.A. It was launched from Cape Canaveral SLC-40 by a Falcon 9 Full Thrust launch vehicle on 4 March 2016.

<span class="mw-page-title-main">Ariane flight VA241</span> Space launch

Ariane flight VA241 was an Ariane 5 space launch that occurred from the Guiana Space Centre on 25 January 2018 at 22:20 UTC.

References

  1. ↑ "U.S. Government Orbital Debris Mitigation Standard Practices" (PDF). United States Federal Government. Retrieved 2013-11-28.
  2. 1 2 Luu, Kim; Sabol, Chris (October 1998). "Effects of perturbations on space debris in supersynchronous storage orbits" (PDF). Air Force Research Laboratory Technical Reports (AFRL-VS-PS-TR-1998-1093). Bibcode:1998PhDT.......274L. Archived (PDF) from the original on December 3, 2013. Retrieved 2013-11-28.
  3. ↑ Frank Zegler and Bernard Kutter, "Evolving to a Depot-Based Space Transportation Architecture" Archived 2011-07-17 at the Wayback Machine , AIAA SPACE 2010 Conference & Exposition, 30 August-2 September 2010, AIAA 2010–8638.
  4. 1 2 Svitak, Amy (2013-11-24). "Musk: Falcon 9 Will Capture Market Share". Aviation Week. Retrieved 2013-11-28.
  5. 1 2 de Selding, Peter B. (6 January 2014). "SpaceX Delivers Thaicom-6 Satellite to Orbit". Space News. Archived from the original on January 7, 2014. Retrieved 7 January 2014.
  6. ↑ "Independent Enquiry Commission announces conclusions concerning the launcher trajectory deviation during Flight VA241 - Arianespace". Arianespace. Retrieved 23 February 2018.
  7. 1 2 Lodders, Katharina; Fegley, Bruce (1998). The planetary scientist's companion. Oxford University Press US. pp. 190, 198. ISBN   0-19-511694-1.
  8. ↑ "Trajectory Design" (PDF (5.37Mb)). Indian Space Research Organisation (ISRO ). October 2013. Retrieved 2013-10-08.
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