Sensing small-scale structures in the lower Martian atmosphere with tomographic principles

As discussed recently at the Ninth International Conference on Mars, held from July 22-25 2019 in Pasadena, CA, small-scale atmospheric structures and the diurnal temperature cycle in the lower Martian atmosphere are both under-sampled by the available record of observations. In order to address the existing gaps in the Mars observation network, we propose a mission concept which is based on a series of cubesats, carried to Mars and injected into a so-called pearls-on-a-string constellation. For best global and temporal coverage, a circular orbit with an altitude of about 370 km, an inclination of about 60 degrees and a separation of the satellites in mean anomaly of about six degrees is assumed. With this constellation, planetary and cross-link observations to existing orbiters in X-band and UHF-band are obtained, which are well-suited for tomography processing.

In contrast to existing radio occultation missions, the suggested cubesat constellation allows for alternative processing of the radio signals using tomographic principles. With the tomography technique the obtained radio signals are processed together for the retrieval of two-dimensional temperature and pressure fields with a horizontal resolution of about 10 km and vertical resolution of 0.5 km. These fields will provide us a better insight into small-scale processes in the lower Martian atmosphere - especially of those that are characterized by distinct horizontal gradients, vertical convection, water ice clouds, planetary and gravity waves. Since radio signals are less sensitive to dust, we expect also new perceptions about atmospheric processes during dust storms.

For the proof of concept, various atmospheric conditions were simulated and processed in an end-to-end simulation. In this presentation, we will show selected results of these simulations to highlight the potential of atmospheric tomography and of dedicated cubesat missions, optimized for tomography processing.