Areostationary orbit - Revision history

CZMatt at 05:44, 7 December 2019

2019-12-07T05:44:51Z

Michel Lamontagne at 21:38, 19 April 2019

2019-04-19T21:38:57Z

Michel Lamontagne at 21:38, 19 April 2019

2019-04-19T21:38:24Z

Pb: /* Satellite Coverage */

2018-09-01T03:34:24Z

Satellite Coverage

Pb: /* Satellite Coverage */

2018-09-01T03:06:51Z

Satellite Coverage

Pb at 04:05, 30 August 2018

2018-08-30T04:05:15Z

Pb: fixing ref

2018-08-30T03:51:25Z

fixing ref

Pb: /* Satellite Coverate */

2018-08-30T03:45:42Z

Satellite Coverate

Pb: /* Stable Orbital Slots */

2018-08-30T03:44:29Z

Stable Orbital Slots

Pb: creating aerostationary orbit

2018-08-30T03:43:02Z

creating aerostationary orbit

New page

A satellite in areostationary orbit is a satellite in a circular, [[synchronous orbit]] at the equator, making it appear stationary in the sky above the ground.

As shown on the [[synchronous orbit]] page, a satellite must have a semi-major axis of 20,427.7 km to have its orbital period equal the rotational period of Mars. Since an aerostationary satellite is in a circular orbit, the orbital radius equals the semi-major axis, 20,427.7 km, placing it at an altitude of 17,038.2 km above the Martian surface. This puts Mars stationary orbit above Phobos (9,376 km) and below Deimos (23,463 km).

==Stable Orbital Slots==
Mars is not perfectly spherical, and so most satellites in areosynchronous orbit will tend to drift if left free-flying without station-keeping maneuvers. However, there are latitudes which have been shown to be equilibrium points in areosynchronous orbit. The are two stable equilibrium points at 17.92W and 167.83E, and there are two unstable equilibrium points at 105.55W and 75.34E.<ref name="Silvaa"/>

==Satellite Coverate==
For an areostationary satellite, coverage can be approximated as a circular region below the satellite. This coverage area could be defined as one in which all points remain in the satellite's field of view at all times, or an area in which a unit on the ground maintains contact with the areostationary satellite at all times.

In the case where the satellites coverage defines an area in which a unit on the ground maintains contact with the satellite, for instance if the satellite were used as a radio relay, one might start by assuming that contact can be established if the satellite is at least 10 degrees above the horizon. In this case, the coverage zone would be a circle with a radius of approximately 4176 km. The coverage zone in this image is centered on the equator at 180 degrees latitude.

[[Image:AreostationaryCoverage.png]]

<ref name="Silvaa">{{cite journal |author1=Silvaa, J. |author2=Romero, P. |title=Optimal longitudes determination for the station keeping of areostationary satellites |journal=Planetary and Space Science |volume=87 |issue=October |year=2013}}</ref>

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 A more realistic plot of coverage might take into account both altitude data and the non-spherical shape of Mars.
-===References===
+== References ==
 <references />

@@ Line 1: / Line 1: @@
 A satellite in areostationary orbit is a satellite in a circular, [[synchronous orbit]] at the equator, making it appear stationary in the sky above the ground.
-As shown on the [[synchronous orbit]] page, a satellite must have a semi-major axis of 20,427.7 km to have its orbital period equal the rotational period of Mars. Since an aerostationary satellite is in a circular orbit, the orbital radius equals the semi-major axis, 20,427.7 km, placing it at an altitude of 17,038.2 km above the Martian surface. This puts Mars stationary orbit above Phobos (9,376 km) and below Deimos (23,463 km).
+As shown on the [[synchronous orbit]] page, a satellite must have a semi-major axis of 20,427.7 km (17 000 km above the surface) to have its orbital period equal the rotational period of Mars. Since an aerostationary satellite is in a circular orbit, the orbital radius equals the semi-major axis, 20,427.7 km, placing it at an altitude of 17,038.2 km above the Martian surface. This puts Mars stationary orbit above Phobos (9,376 km) and below Deimos (23,463 km).
 ==Stable Orbital Slots==
@@ Line 20: / Line 20: @@
 ===References===

@@ Line 9: / Line 9: @@
 For an areostationary satellite, coverage can be approximated as a circular region below the satellite. This coverage area could be defined as one in which all points remain in the satellite's field of view at all times, or an area in which a unit on the ground maintains contact with the areostationary satellite at all times.
-In the case where the satellites coverage defines an area in which a unit on the ground maintains contact with the satellite, for instance if the satellite were used as a radio relay, one might start by assuming that contact can be established if the satellite is at least 10 degrees above the horizon. In this case, the coverage zone would be a circle with a radius of approximately 4176 km, with the top of the coverage zone reaching a latitude of approximately 78.2°.
+[[Image:StationarySatelliteFOV.png]]
 [[Image:AreostationaryCoverage.png]]
 The coverage zones in this map approximate those of satellites in the two stable equilibrium points (yellow) and the two unstable equilibrium points (cyan). Plotted with Leaflet using tiles from [https://github.com/openplanetary/opm/wiki/OPM-Basemaps OpenPlanetaryMap].
 ===References===

@@ Line 9: / Line 9: @@
 For an areostationary satellite, coverage can be approximated as a circular region below the satellite. This coverage area could be defined as one in which all points remain in the satellite's field of view at all times, or an area in which a unit on the ground maintains contact with the areostationary satellite at all times.
-In the case where the satellites coverage defines an area in which a unit on the ground maintains contact with the satellite, for instance if the satellite were used as a radio relay, one might start by assuming that contact can be established if the satellite is at least 10 degrees above the horizon. In this case, the coverage zone would be a circle with a radius of approximately 4176 km.
+In the case where the satellites coverage defines an area in which a unit on the ground maintains contact with the satellite, for instance if the satellite were used as a radio relay, one might start by assuming that contact can be established if the satellite is at least 10 degrees above the horizon. In this case, the coverage zone would be a circle with a radius of approximately 4176 km, with the top of the coverage zone reaching a latitude of approximately 78.2°.
 [[Image:AreostationaryCoverage.png]]
-The coverage zone plotted in this map is centered on the equator at 180 degrees latitude. The locations on the map, from left to right, are Jezero Crater (a NASA Mars 2020 rover candidate site), Elysium Planitia (InSight planned landing site), Gale Crater (Curiosity landing site), Columbia Hills (NASA Mars 2020 candidate), Oxia Planum (ExoMars 2020 candidate), and Mawrth Vallis (ExoMars 2020 candidate). It was plotted with Leaflet and Mapbox. Unfortunately, the Mapbox tiles are no longer available, but the source code for this map remains available here: <ref name="pbrandt">https://github.com/pbrandt1/flight-dynamics-tutorials/blob/master/Mars_Stationary_Satellite.md</ref>
+The coverage zones in this map approximate those of satellites in the two stable equilibrium points (yellow) and the two unstable equilibrium points (cyan). Plotted with Leaflet using tiles from [https://github.com/openplanetary/opm/wiki/OPM-Basemaps OpenPlanetaryMap].
 ===References===

@@ Line 4: / Line 4: @@
 ==Stable Orbital Slots==
-Mars is not perfectly spherical, and so most satellites in areosynchronous orbit will tend to drift if left free-flying without station-keeping maneuvers. However, there are latitudes which have been shown to be equilibrium points in areosynchronous orbit. There are two stable equilibrium points at 17.92W and 167.83E, and there are two unstable equilibrium points at 105.55W and 75.34E.<ref name="Silvaa"/>
+Mars is not perfectly spherical, and so most satellites in areosynchronous orbit will tend to drift if left free-flying without station-keeping maneuvers. However, there are latitudes which have been shown to be equilibrium points in areosynchronous orbit. There are two stable equilibrium points at 17.92W and 167.83E, and there are two unstable equilibrium points at 105.55W and 75.34E.<ref name="Silvaa">{{cite journal |author=Juan J. Silvaa and Pilar Romero Silvaa |title=Optimal longitudes determination for the station keeping of areostationary satellites |journal=Planetary and Space Science |volume=87 |issue=October |year=2013}}</ref>
 ==Satellite Coverage==
@@ Line 12: / Line 12: @@
 [[Image:AreostationaryCoverage.png]]