# Areostationary orbit

An areostationary orbit (abbreviated ASO) is a circular areo­synchronous orbit in the Martian equatorial plane about 17,000 km (11,000 mi) above the surface, any point on which revolves about Mars in the same direction and with the same period as the Martian surface. Areo­stationary orbit is a concept similar to Earth's geo­stationary orbit.

Although to date, no artificial satellites have been placed in this orbit, it is of interest to some scientists foreseeing a future tele­communications network for the exploration of Mars.[1]

The proposed Mars One mission includes a communications system featuring amongst others things an areostationary satellite.[2]

An asteroid or station placed in areostationary orbit could also be used to construct a Martian space elevator for use in transfers between the surface of Mars and orbit.

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).

## Formula

The formula for finding the geostationary orbit of any planetary body (including Mars) is located in the article Geostationary orbit.[citation needed]

Orbital speed (how fast a satellite is moving through space) is calculated by multiplying the angular speed of the satellite by the orbital radius:

$v = \omega r \text{.}$

By this formula we can find the geostationary-type orbit of an object in relation to Mars (this type of orbit above is referred to as an areostationary orbit if it is above Mars). The areogeocentric gravitational constant GM (which is μ) for Mars has the value of 42,828 km3s−2, and the known rotational period (T) of Mars is 88,642.66 seconds. Since ω = 2π/T, using the formula above, the value of ω is found to be approx 7.088218×10−5 s−1. Thus, r3 = 8.5243×1012 km3, whose cube root is 20,427 km; subtracting the equatorial radius of Mars (3396.2 km) we have 17,031 km.