Japan's H3 rocket delivers Mars probe after two-stage propulsion sequence

(SpaceEnergy) Japan's H3 rocket has successfully deployed the Martian Moons eXploration spacecraft on its planned Mars-transfer trajectory, completing a launch requiring two upper-stage engine burns.

The Japan Aerospace Exploration Agency (JAXA) confirmed that H3 flight 10 lifted off from Tanegashima Space Centre at 04:41:03 Japan Standard Time on 20 October.

The rocket flew according to plan and separated the MMX spacecraft approximately 1 hour 11 minutes 13 seconds after launch.

The mission used the H3-24L configuration, incorporating two LE-9 liquid hydrogen–oxygen first-stage engines, four SRB-3 solid rocket boosters and a long payload fairing.

JAXA's flight plan specified an initial firing of the LE-5B-3 upper-stage engine beginning 5 minutes 12 seconds after launch, followed by a second firing approximately 64 minutes after liftoff.

The second burn was designed to accelerate the spacecraft onto its Mars-transfer trajectory, with a planned inertial velocity of approximately 11.2km/s at engine shutdown.

JAXA's confirmation of nominal flight and successful spacecraft separation establishes completion of the launch's principal propulsion objectives.

The 4,480kg MMX spacecraft comprises outbound, exploration and return modules. It is designed to reach the Martian system in 2027, investigate Phobos and Deimos, and return samples collected from Phobos to Earth in 2031.

The successful launch demonstrates H3's capability to deliver a substantial planetary exploration spacecraft onto an interplanetary trajectory.

It does not establish completion of MMX's subsequent cruise propulsion manoeuvres or Mars orbital insertion.