16:15 〜 16:30
[PPS06-10] Martian Moons eXploration MMX: Current Status Report 2021
キーワード：フォボス、ダイモス、火星、MMX、生存可能惑星、初期太陽系
As of February 2021, the MMX project is under the final phase of preliminary design reviews (PDRs), which consist of reviews on specific instruments, subsystems, total system, operations, and integration. Tests using mechanical test models and thermal test models are being conducted. The composition of science instruments (7 sensing instruments, 2 sampler systems, a return capsule, and a rover) is maintained although the architecture of the infrared spectrometer has been changed from a hyperspectrometer to a grating array detector. The plan of observations during the stay in the Mars-moons system is being extensively studied as well as measures for possible regolith contamination onto sensing instruments during landing operations. After passed the PDRs, the MMX project will proceed to phase C or the detailed design phase. Partly due to the effect of the COVID-19 pandemic, the development schedule has been slightly revised so far but maintains the launch year 2024.
The MMX mission is a sample return mission to Phobos, a small inner moon orbiting Mars. Owing to the lack of definitive evidence, the origin of Phobos and the outer Martian moon Deimos is still under debate between two leading hypotheses: the capture of volatile-rich primordial asteroid(s) and the in-situ formation from a debris disk that generated by a giant impact onto early Mars. Whichever theory is correct, the Martian moons are expected to be associated with Mars formation and preserve key records of volatile material transport that would make the terrestrial planets habitable in the early solar system. Through close-up observations of both moons and sample return from Phobos, MMX will settle the controversy of their origin, reveal their evolution, and constrain the early solar system evolution around the region near the snow line. Monitoring of global circulation and escape of the Martian atmosphere will be also conducted to reveal basic processes that have shaped and altered the Martian surface environment.
To achieve a round-trip to the Martian system within a reasonable time, the MMX spacecraft is composed of three modules equipped with a chemical propulsion system and solar generators. By releasing used modules at appropriate timings, the spacecraft mass is reduced to allow orbital tuning to quasi-satellite orbits around Phobos, landing on Phobos surfaces, and the escape from the Martian gravity to the return cruise to the Earth.
MMX will arrive at the Martian system in 2025 and start close-up observations of Phobos after the release of the propulsion module used for Mars orbit insertion. In early 2027, Mars will approach the closest distance from the Earth which minimizes the communication delay between the spacecraft and the Earth station. Together with the timing relatively far from Sun-Mars conjunctions and the Martian equinoxes, this period is the most favorable for landing operations that require real-time communication with the ground station and day-time solar illumination undisturbed by an eclipse. Preceded ~1 year will be largely devoted to landing site selection that requires global and zoom-up observations of Phobos confirming operational safety and availability of Phobos-indigenous materials at landing sites. After the stay near Phobos for ~3 years, the MMX spacecraft will be transferred to Deimos-flyby orbits to conduct Deimos observations, and then only the return module will depart the Martian system leaving the exploration module in a circum-Martian orbit in 2028. The sample capsule will come back to the Earth in 2029.
The MMX mission is a sample return mission to Phobos, a small inner moon orbiting Mars. Owing to the lack of definitive evidence, the origin of Phobos and the outer Martian moon Deimos is still under debate between two leading hypotheses: the capture of volatile-rich primordial asteroid(s) and the in-situ formation from a debris disk that generated by a giant impact onto early Mars. Whichever theory is correct, the Martian moons are expected to be associated with Mars formation and preserve key records of volatile material transport that would make the terrestrial planets habitable in the early solar system. Through close-up observations of both moons and sample return from Phobos, MMX will settle the controversy of their origin, reveal their evolution, and constrain the early solar system evolution around the region near the snow line. Monitoring of global circulation and escape of the Martian atmosphere will be also conducted to reveal basic processes that have shaped and altered the Martian surface environment.
To achieve a round-trip to the Martian system within a reasonable time, the MMX spacecraft is composed of three modules equipped with a chemical propulsion system and solar generators. By releasing used modules at appropriate timings, the spacecraft mass is reduced to allow orbital tuning to quasi-satellite orbits around Phobos, landing on Phobos surfaces, and the escape from the Martian gravity to the return cruise to the Earth.
MMX will arrive at the Martian system in 2025 and start close-up observations of Phobos after the release of the propulsion module used for Mars orbit insertion. In early 2027, Mars will approach the closest distance from the Earth which minimizes the communication delay between the spacecraft and the Earth station. Together with the timing relatively far from Sun-Mars conjunctions and the Martian equinoxes, this period is the most favorable for landing operations that require real-time communication with the ground station and day-time solar illumination undisturbed by an eclipse. Preceded ~1 year will be largely devoted to landing site selection that requires global and zoom-up observations of Phobos confirming operational safety and availability of Phobos-indigenous materials at landing sites. After the stay near Phobos for ~3 years, the MMX spacecraft will be transferred to Deimos-flyby orbits to conduct Deimos observations, and then only the return module will depart the Martian system leaving the exploration module in a circum-Martian orbit in 2028. The sample capsule will come back to the Earth in 2029.