M5 -- Mars Magnetospheric Multipoint Measurement Mission: A multi-spacecraft plasma physics mission to Mars

TL;DR

The paper proposes M5, a five-spacecraft mission to Mars designed to comprehensively characterize the induced Martian magnetosphere under varying solar wind conditions. It defines a two-tier science program (primary and secondary questions) and an instrument plan that enables 3D, time-resolved measurements of magnetic fields, particle distributions, and electric fields via a four-spacecraft tetrahedron plus a solar wind monitor. The authors present a detailed mission design, including orbit geometries, formation flying, heritage instruments, and comprehensive budgets (mass, power, thermal, telemetry), arguing that the concept is feasible within an ESA L-class framework. The work advances understanding of magnetospheric dynamics, reconnection in the Martian tail, and atmospheric escape, providing a vital reference for future Mars exploration and comparative studies of induced magnetospheres.

Abstract

Mars, lacking an intrinsic dynamo, is an ideal laboratory to comparatively study induced magnetospheres, which can be found in other terrestrial bodies as well as comets. Additionally, Mars is of particular interest to further exploration due to its loss of habitability by atmospheric escape and possible future human exploration. In this context, we propose the Mars Magnetospheric Multipoint Measurement Mission (M$^5$), a multi-spacecraft mission to study the dynamics and energy transport of the Martian induced magnetosphere comprehensively. Particular focus is dedicated to the largely unexplored magnetotail region, where signatures of magnetic reconnection have been found. Furthermore, a reliable knowledge of the upstream solar wind conditions is needed to study the dynamics of the Martian magnetosphere, especially the different dayside boundary regions but also for energy transport phenomena like the current system and plasma waves. This will aid the study of atmospheric escape processes of planets with induced magnetospheres. In order to resolve the three-dimensional structures varying both in time and space, multi-point measurements are required. Thus, M$^5$ is a five spacecraft mission, with one solar wind monitor orbiting Mars in a circular orbit at 5 Martian radii, and four smaller spacecraft in a tetrahedral configuration orbiting Mars in an elliptical orbit, spanning the far magnetotail up to 6 Mars radii with a periapsis within the Martian magnetosphere of 1.8 Mars radii. We not only present a detailed assessment of the scientific need for such a mission but also show the resulting mission and spacecraft design taking into account all aspects of the mission requirements and constraints such as mass, power, and link budgets. This mission concept was developed during the Alpbach Summer School 2022.

Figures (9)

• Figure 1: Overview of the Martian induced magnetosphere. The Interplanetary Magnetic Field (IMF) is draped around the planet, forming boundary regions and a highly dynamical magnetotail that is yet to be studied in detail. The numbers indicate the different plasma zones addressed in the text. 1. Solar wind, 2. IMF, 3. Sub-solar point of the bow shock, 4. Sub-solar point of the magnetic pile-up boundary, 5. Ionosphere, 6. Crustal field, 7. Lobes of the magnetotail, 8. Plasma sheet of the magnetotail.
• Figure 2: Final orbit configuration of MFOs and SWO at Mars. Due to orbit precession, the orbit of the MFOs will move relative to the Martian reference frame during the Martian year "sweeping" over regions of interest (e.g. boundary crossings marked with red dots).
• Figure 3: Three-dimensional rendering of the two spacecraft types forming the M$^5$ mission.
• Figure 4: Spacecraft in the launch configuration inside the Ariane's fairing.
• Figure 5: Mission trajectory close to Mars in Mars-Solar-orbital coordinates. The approach trajectory of the five spacecraft is shown in green. At the end of the approach trajectory an Orbit Insertion Maneuver (OIM) is performed to reach the capture orbit show in blue. Following the OIM the spacecraft separate. From the capture orbit, SWO lowers first its apoapsis, and finally increases its periapsis to reach its circular target orbit ($\mathrm{5 R_m \times 5 R_m}$) shown in orange. After the SWO has finished its maneuvers, the MFOs lower their apoapsis and raise their periapsis to reach their target orbit ($\mathrm{1.8 R_m \times 6 R_m}$) shown in red. The inclination of the orbital plane is $150^{\circ}$ for all orbits. A more detailed description of the maneuvers is provided in \ref{['sec:orbit']}.