A Micro-Meteorological mission for global network science on Mars: Rationale and measurement requirements

The general circulation of the Martian atmosphere and how it relates to the planet's climate system are the main goals of post-Viking atmospheric science investigations. An unambiguous determination of the wind systems associated with the general circulation requires simultaneous measurements from at least 15-20 globally-distributed surface stations and a single, high inclination, short period orbiter. The required number of stations would be too costly using conventional multi-instrumented lander designs. However, truly global network science for meteorology can be accomplished using landers instrumented for a single measurement, namely pressure. Pressure is the most important meteorological parameter and pressure sensors do not require deployment or orientation. This facilitates the design of relatively simple landers that are sufficiently small and light that the required number can be launched on a single Med-Lite launch vehicle (see the accompanying paper by Merrihew et al. (Planet. Space Sci. 44, 1385-1393, 1996)). Of equal importance, the low power demand of the stations would allow them to last for a Martian year and provide the necessary seasonal coverage. The rationale and measurement requirements are given for such a network, and it is shown how it would contribute to the understanding of the Martian general circulation and climate system. In particular, the number and siting of stations is discussed, and the basic science specifications for barometric pressure sensors and an atmospheric sounder. The proposed mission would, for the first time, observationally define the seasonally-varying global wind held on another planet.