Rover on the home stretch to the Martian moon Phobos
JAXA, CNES and DLR sign a cooperation agreement on the MMX mission on 20 June 2023 in Paris. The Institute of Robotics and Mechatronics is coordinating the project on the DLR side.
The origin of the Martian moons Phobos and Deimos is still an unsolved mystery in planetary research. Both moons are the target of the Japanese mission Martian Moons eXploration (MMX). A German-French rover is to land on Phobos as part of the mission and explore it on a rolling basis - despite extremely low gravity. At the international aerospace trade fair Paris Air Show in Le Bourget, the Japanese space agency JAXA (Japan Aerospace Exploration Agency) signed an agreement with the German Aerospace Center (DLR) and the French space agency CNES (Centre national d'études spatiales) on trilateral cooperation within the framework of the MMX mission. Meanwhile, the completion of the rover, including instruments and systems, is on the home stretch towards summer 2023. In parallel with the signing, the rover will be named IDEFIX.
"We are delighted that CNES and DLR are working with us on the MMX mission. MMX aims to clarify the origins of the Martian moons and better understand the evolutionary process of the Martian system by collecting samples from Phobos, one of the two Martian moons, for the first time in the history of spaceflight," says Dr Hiroshi Yamakawa, President of JAXA. He adds: "Japan shares with France and Germany precious memories of cooperation in the Hayabusa2 sample return mission, in which the Franco-German lander MASCOT already flew. We look forward to combining our efforts again for a successful mission MMX."
Prof. Dr.-Ing. Anke Kaysser-Pyzalla, Chair of the DLR Executive Board, said on the occasion of the signing: "Japan and France are important strategic partner countries for DLR in almost all of our research areas. The cooperation within the framework of the MMX mission is a particular example of the creative power of our multifaceted collaboration. When a rover rolls over the surface of the Martian moon Phobos for the first time, we will have pushed technological boundaries together. Together, we want to learn more about the origins of our solar system and Mars with its moons."
Dr Walther Pelzer, DLR Executive Board member and Head of the German Space Agency at DLR emphasises, "MMX is a very good example of how challenging space missions can be carried out in international cooperation: As a joint endeavour, together with nations, space agencies and partners pursuing the same goal. Each side brings its particular competencies to the table. The costs and risks will be shared to jointly achieve exceptional technological expertise and scientific results."
"The signing of this new trilateral agreement between CNES, JAXA and DLR is another milestone in the fruitful collaboration between our three nations on the MMX mission. By studying the two moons of Mars, Phobos and Deimos, this mission will lead to major advances in the exploration of our solar system," says Dr Philippe Baptiste, CEO of CNES.
With the cooperation agreement, JAXA, CNES and DLR are creating a joint framework for the integration of the Franco-German rover into the Japanese MMX mission for a joint landing on the Martian moon Phobos in the second half of the 2020s. MMX is a mission at the limits of what is technically feasible. For the first time, samples from the Martian system, specifically from the Martian moon Phobos, are to be brought to Earth by means of the Japanese mother probe. Beforehand, the German-French rover will roll over the surface of Phobos at extremely low gravity (two-thousandths of the Earth's gravity) in order to explore it. The MMX rover was developed according to this unique and challenging idea and was named IDEFIX today.
The final work to complete the rover is currently underway at the CNES site in Toulouse. In the last few months, the final integration of all instruments and subsystems, including the solar panels, power system, on-board computer and radio system for contact with the MMX mothership, has taken place there. Previously, DLR had already integrated the carbon structure of the rover, including the erection and propulsion system, at the Bremen site and delivered it to CNES in Toulouse in November 2022, as well as the miniRAD radiometer and the RAX spectrometer from DLR's Berlin site. In addition to the two DLR instruments for analysing the thermal properties and mineralogical composition of the surface, CNES has mounted two wheel cameras to keep an eye on the wheels and the ground, and integrated two navigation cameras.
In the meantime, the complete rover has almost completely undergone the final space qualification tests at CNES in Toulouse, among other things with regard to its functions and resistance to the vibrations of the rocket launch and to the extreme temperature fluctuations of more than 200 degrees Celsius on Phobos. The qualification tests of the rover are already taking place together with the connection and separation system to the mother ship, called "MECSS" (Mechanical and Electrical Connection and Support System). This adapter was also provided by DLR. The communication system developed by CNES, which transmits commands and telemetry, is also being tested during the qualification campaign. The rover test campaign is now on the home straight. Before delivery in the summer, the electromagnetic compatibility (EMC) test and some final checks still need to be carried out.
MMX spacecraft
The MMX spacecraft consists of three modules. The exploration module has landing legs, samplers and some instruments as well as the MMX rover on board. The exploration module is connected to the return module and to the sample retrieval capsule. This in turn has a connection to the propulsion module, which is equipped with fuel tanks and rocket engines. Construction of the MMX mothership has now been completed. The project team has started the final integration and testing of the spacecraft, including the instruments provided by the partner organisations, towards the targeted launch window of 2024.
The mission sequence
The mission is scheduled to launch in the mid-2020s. After about one year of flight, MMX will reach Mars and enter its orbit. Then the eight scientific instruments of the exploration module will begin mapping and characterising the surfaces of Phobos and Deimos. During the course of the mission, the rover is scheduled to land on Phobos. The rover will be lowered from an altitude of 40 to 100 metres above the surface. After landing, it will set itself up on its own to get ready for operation. The measurement phase, which will last about three months, will then begin, during which the rover will approach various targets that are of interest for scientific analysis. At the end of the mission, ground samples will be collected by the mother probe, taking into account the knowledge also gained by the rover. These will be sent back to Earth with the return module for more detailed analyses.
Where did "fear" and "terror" come from?
Phobos and Deimos (in German: Furcht und Schrecken) accompany the planet Mars as moons. In Greek mythology they are the companions of the god of war Ares, who in Roman antiquity has his counterpart in the god of war Mars. Phobos and Deimos were discovered in 1877 by the American astronomer Asaph Hall. Due to their small size (Phobos 27 kilometres in the largest diameter, Deimos 15 kilometres), both moons are irregularly shaped and their shape is more reminiscent of asteroids. One theory is that Mars "captured" the two bodies in the past, possibly in the asteroid belt. However, the very narrow and almost circular orbits of both moons in the equatorial plane of the planet are difficult to explain. These would be better understood if Phobos and Deimos were remnants of a huge meteorite impact on Mars.
MMX should solve the long-discussed riddle of planetary science. The formation of the Martian system is also a key to better understanding the processes of planet formation in the solar system as a whole. In any case, traces of Martian rocks are likely to be found on the surface of Phobos, which landed on Phobos as ejecta from later asteroid impacts. This means that material from Mars could then also reach Earth in the return capsule along with the samples from Phobos and thus reach terrestrial laboratories.
