Theareosynchronous orbits (ASO) are thesynchronous orbits forartificial satellites around the planetMars. They are the martian equivalent of thegeosynchronous orbits (GSO) on theEarth. The prefixareo- derives fromAres, the ancientGreek god of war and counterpart to theRoman godMars, with whom the planet was identified. Themodern Greek word for Mars isΆρης (Áris).
As with all synchronous orbits, an areosynchronous orbit has anorbital period equal in length to the primary'ssidereal day. A satellite in areosynchronous orbit doesnot necessarily maintain a fixed position in the sky as seen by an observer on the surface of Mars; however, such a satellite will return to the same apparent position every Martian day.
Theorbital altitude required to maintain an areosynchronous orbit is approximately 17,000 kilometres (11,000 mi). If a satellite in areosynchronous orbit were to be used as acommunication relay link, it "would experience communications ranges of 17,000 to 20,000 kilometres (11,000 to 12,000 mi)" to various points on the visible Martian surface.[1]
An areosynchronous orbit that is equatorial (in the same plane as theequator of Mars), circular, andprograde (rotating about Mars's axis in the same direction as the planet's surface) is known as anareostationary orbit (AEO). To an observer on the surface of Mars, the position of a satellite in AEO would appear to be fixed in a constant position in the sky. The AEO is analogous to ageostationary orbit (GEO) about Earth.
Although no satellites currently occupy areosynchronous or areostationary orbits, some scientists foresee a futuretelecommunications network for the exploration of Mars.[2]
