Japan schedules first Phobos sample mission for October launch
Returned material could settle whether Phobos formed with Mars
Overview
Japan is preparing , the first mission designed to bring samples from a moon of Mars to Earth. An is scheduled to launch it in October 2026. The spacecraft should reach Mars in August 2027, study Phobos and Deimos for about five years, then send a sample capsule to Australia in 2031.
will orbit Mars in a path that lets it study both moons instead of orbiting Phobos directly. A rover will examine Phobos’s and help choose two short landing sites. The spacecraft aims to collect at least 10 grams. Tests on Earth could show whether Phobos formed with Mars or is a captured asteroid. That finding could reveal how material moved through the early Solar System and how planets formed.
Timeline
MMX is scheduled to deliver Phobos samples to Australia for recovery
In 2031, MMX is planned to release a sample return capsule for and landing in Australia’s . Recovery teams will transfer the capsule for extraction, cataloguing, , and distribution to researchers. The returned material could clarify Phobos’s origin, Mars’s history, and how planetary material moved through the early Solar System.
MMX is planned to leave Mars with Phobos samples secured for Earth return
After completing observations and sampling, the spacecraft is scheduled to depart the Martian system on a lasting about one year. The return phase must preserve the collected material and keep the sample container on course for Earth. Planned operations may also include additional observations during the departure sequence.
MMX plans two Phobos landings to collect at least 10 grams of material
The main spacecraft is planned to land briefly at two sites on Phobos and collect a minimum of 10 grams of surface material. Sampling separate locations can reveal whether the moon is compositionally uniform, contains mixed source material, or includes Martian debris. Laboratory analysis could distinguish from material formed within the Martian system.
MMX is scheduled to deploy its rover on Phobos for surface reconnaissance
The rover will descend to and examine the surface directly, providing images and terrain information near potential sampling areas. Its reconnaissance is intended to improve understanding of the moon’s loose, low-gravity surface and support safe landings by the main spacecraft. Rover data will complement measurements made from the .
MMX is planned to map both moons before shifting to close Phobos operations
MMX will make detailed observations of Phobos and Deimos using imaging and scientific instruments designed to characterize their surfaces and composition. These measurements will establish the moons’ physical and and guide later operations. Comparing both bodies helps test whether they share a Martian origin or reflect different .
MMX is scheduled to reach Mars and begin surveys of Phobos and Deimos
NASA says MMX is expected to arrive at Mars in August 2027 and begin surveying the planet’s two moons. The spacecraft will first operate in a around Mars rather than orbiting Phobos directly. This configuration allows precise navigation and broad observations before close Phobos operations.
JAXA plans to launch MMX on an H3 rocket from Tanegashima
The mission is scheduled to depart Japan in October 2026 aboard an . Launch begins the and the systems checks required before the spacecraft reaches Mars. The launch plan is the operational starting point for the approximately five-year sample-return mission.
JAXA set MMX on a roughly five-year route from Earth to Phobos and back
The mission plan called for launch in Japan’s fiscal year 2026, operations in the , and sample delivery to Earth in 2031. MMX would conduct detailed measurements of both moons before attempting the first sample return from the . The planned schedule made engineering reliability central to the scientific investigation.
JAXA and international partners advanced MMX as a two-moon survey and sample-return mission
JAXA developed MMX to study both and , land on , collect material, and return it to Earth. NASA, CNES, DLR, and ESA joined the mission with spacecraft, instruments, and scientific support. The architecture connects remote sensing, rover reconnaissance, surface sampling, and Earth-based analysis.
JAXA selected Phobos sample return as a test of the Martian system’s origin
Scientists proposed to investigate whether Phobos formed alongside Mars or was captured from the asteroid population. Remote observations had not resolved the competing explanations, making returned material necessary for laboratory analysis. The mission also links Phobos to questions about and in the early Solar System.