The MMX sampling instrument (C-SMP and SSTM) for collecting material from Phobos joined the comprehensive spacecraft system tests

One of the 13 instruments onboard the Martian Moons eXploration (MMX) mission spacecraft, and at the heart of the sample return mission, is the sampler needed to collect and return material from Phobos. Two of the instruments for this purpose are the “C-SMP” (corer sampler) and the “SSTM” (Sample Storage and Transfer Mechanism).

The C-SMP is a robotic arm equipped with sensors. After the spacecraft lands on Phobos, the arm will photograph the surrounding terrain and transmit live images and 3D terrain data back to Earth. The arm will then gather regolith from a depth up to 2cm on the Martian moon’s surface, avoiding small stones and hard areas around a sampling point designated by the ground operations team. After the landing operation on Phobos is complete, the collected sample will be stored in the corer storage section of the SSTM. The SSTM will then transfer the stored sample to the Sample Return Capsule (SRC) to be brought back to Earth, and seal the sample container in a vacuum to preserve its scientific integrity.

Left: C-SMP FM (Flight Model): the right-side is the robotic arm manipulator that is in the position for launch. The left-side structure is the manipulator hand. The corer mechanism is mounted on the cylindrical part inside the bag covering the hand, and the camera is used to search and select areas where sampling can be done safely. Right: Group photograph at the handover of the C-SMP, taken in the cleanroom at MELCO Kamakura. From left to right on the front row are Tanaka Daiki, Kato Hiroki (JAXA), Sakamoto Fuminobu, Fukii Shuta (Kawasaki Heavy Industries). On the back row, Sawada Hirotaka (JAXA), Onitsuka Kazuhiko, Murase Kengo, Irimatsukawa Yuta (Kawasaki Heavy Industries).

The basic design for the C-SMP began at the development manufacturer (Kawasaki Heavy Industries, Ltd.) in April 2019. After undergoing design review, engineering model (EM) manufacturing, and the different development tests, the C-SMP was installed on the spacecraft in April 2024, ready for the Flight Model (FM) comprehensive test.

Left: SSTM FM (flight model). The manipulator for the C-SMP stores the samples from the corer and P-SMP (second sampling mechanism) in the sample storage unit (cylindrical equipment arranged in two rows and two columns at the centre-right of the photo) visible in the foreground. SSTM then transports these to the Sample Return Capsule (SRC) and vacuum seals these for scientific purposes. Right: Group photo from the handover of the SSTM, taken in the cleanroom at MELCO Kamakura. From left to right are Kato Hiroki (JAXA), Watanabe Hajime, Miyaoka Mikio, Yamaji Kosuke (Sumitomo Heavy Industries), Sawada Hirotaka, Tanaka Daiki (JAXA).

The basic design of the SSTM began at the development manufacturer (Sumitomo Heavy Industries, Ltd.) in July 2019. The SSTM also then underwent the design review, EM manufacturing, and development tests, before passing the Post Qualification Test Review (PQR) and Pre-Shipping Review (PSR), which together confirm the completion of the development of the Flight Model (FM).

After C-SMP was transported to the spacecraft system manufacture (Mitsubishi Electric Corporation) site at Kamakura Works in April 2024, and the SSTM was transported in July. The pair were officially handed over after functionality confirmation after transportation.

The C-SMP and SSTM will now join the comprehensive spacecraft system tests.

C-SMP Principal Investigator (PI) KATO Hiroki
JAXA

Since study of the sampling device began in 2015, we have overcome steep peaks and troughs to finally make it this far. First of all, I would like to express my gratitude to all the people who have been involved. As a robotics expert, I am looking forward to a future where robotic missions are launched freely into space. And the MMX sampling device is a historic step that we can be proud to share with the world. If MMX travels to the Martian sphere and successfully returns samples, there will be more and more talk about crewed Mars exploration, and we will feel that we have contributed to the progress of humanity. I was actually the person who proposed the name “Martian Moons eXploration (MMX)” that was adopted during a team discussion to select the mission name in the early stages of the mission. (I only suggested “MMX” instead of the first proposal, “Martian Moons Exploration: MME.) So I am one of the “parents” who raised MMX with love, and I feel a great responsibility and have a special affiliation with the mission. I will never let up until the launch.

C-SMP development company representative SAKAMOTO Fuminobu
Space Systems Engineering Section, Space Systems Engineering Department, Defense & Space Systems Group, Defense & Aerospace Business Division, Aerospace Systems Company, Kawasaki Heavy Industries, Ltd.

Due to the limited time that C-SMP can stay on the surface of Phobos, the sampling process cannot be fully controlled from the ground. Therefore, C-SMP must be able to make autonomous decisions to collect the samples. We had repeated discussions with JAXA members to determine how to autonomously conduct the sampling on the surface, which is subject to many uncertainties. We plan to keep working with JAXA and Mitsubishi Electric to ensure that this mission is accomplished.

SSTM development company representative MIYAOKA Mikio
Industrial Equipment Division, Medical and Advanced Equipment Division, Design Department, Sumitomo Heavy Industries, Ltd.

SSTM is an instrument which is the connecting link in the mission, receiving the samples from Phobos collected by the corer and placing these into the sample return capsule that will return to the Earth. We followed the mechanisms proven with Hayabusa2, but unexpected malfunctions occurred and there were struggles during the development. We are pleased that the handover is now complete, but SSTM does now need to be reassembled once the mechanism is operated after the sample operation is performed during the comprehensive tests. We will approach this challenge with a sense of determination!