Mars in sight: Jena-Optronik sensors to navigate JAXA’s MMX mission to the Martian moons
Launched on October 20, 2026, the Martian Moons eXploration (MMX) mission by the Japan Aerospace Exploration Agency (JAXA) aims to explore the Martian moons, Phobos and Deimos, to uncover their origins and gain deeper insights into the history of the solar system.
The MMX space probe will land on Phobos, collect more than 10 grams of material, and return it to Earth, with the sample return expected in 2031. This mission seeks to answer a fundamental scientific question: whether the Martian moons are captured asteroids or debris formed from a massive impact on Mars.
Two ASTRO APS star sensors developed and built by Jena-Optronik will guide this groundbreaking mission to its target.
The MMX mission is led by JAXA and represents an international endeavor involving NASA, CNES, DLR, and ESA. Mitsubishi Electric Corporation (MELCO) serves as the prime contractor, responsible for the mission's overall development and manufacturing. Jena-Optronik provides as key supplier to MELCO the ASTRO APS star sensors as part of the Attitude and Orbit Control (AOCS) system of MMX and thus has a vital role in ensuring the mission's success.
Star sensors act as the primary "eye" for the space probe’s AOCS system:
- Precision navigation baseline: Capture the surrounding star field and instantly compare it with an integrated star catalog to determine the probe's exact orientation in space.
- Trajectory accuracy: Pinpoint navigation data is essential for the interplanetary transfer flight to Mars and the complex orbital insertion around Phobos and Deimos.
- Instrument target alignment: Scientific instruments (cameras, spectrometers) rely on a high-precision pointing to gather accurate data from the Martian moon surfaces.
- Critical descent and sample return: Safe rover deployment and surface sampling require ultra-stable positioning during close-proximity operations and descent corridors.
The ASTRO APS provides specific technological advantages tailored to the extreme demands of deep-space missions:
- High radiation hardness: Built on advanced Active Pixel Sensor (CMOS) technology, the ASTRO APS is characterized by exceptional resistance to harsh cosmic radiation encountered during interplanetary transit.
- Extensive flight heritage: As one of the market's most trusted star sensors, it provides proven reliability for high-stakes science and exploration missions.
- Optimized SWaP (Size, Weight, and Power): It delivers high-accuracy performance within a lightweight, low-power design, which is a vital factor for deep-space payloads.
- Fast "Lost-in-Space" autonomous recovery: Capable of acquiring orientation within seconds without prior attitude information, even following unexpected maneuvers or disturbances.
- Superior stray light rejection: Advanced optical design prevents light reflections from the sun or moon surfaces blinding the sensor during close-approach operations
- Proven surface heritage: The ASTRO APS brings direct lunar landing heritage, having successfully landed and operated on the surface of Earth's Moon as part of JAXA’s SLIM ("Smart Lander for Investigating Moon") mission.
Pictures: © Jena-Optronik GmbH
