Overview
- The Mercury Transfer Module separated from the two science orbiters on Thursday, Sept. 3, triggering live telemetry checks and a planned pause in ESA’s webcast while teams confirm signal acquisition.
- After separation the two orbiters will operate as a single stacked pair while the Mercury Planetary Orbiter uses its chemical thrusters to perform linked burns that aim for Mercury gravity capture on Nov. 21.
- If the capture burns go to plan, ESA’s MPO will release JAXA’s Mio into its final magnetospheric orbit on Dec. 9–10, with MPO moving toward its own final orbit through March 10, 2027.
- Mission leaders warn the arrival phase is highly risky because Mercury’s extreme heat and intense solar radiation shape every maneuver and hardware choice, making the separation effectively like launching a new spacecraft near another planet.
- The paired orbiters carry complementary instruments to map Mercury’s surface composition, probe its interior and study the magnetosphere and exosphere, and any major anomaly during arrival could delay the start of formal science operations slated for April 6, 2027.