BepiColombo to Probe Mercury's 85% Core and 1.5-Km Cliffs in November 2026

1 articles · Updated · spacedaily.com · Aug 9

21 November 2026 is the scheduled date for BepiColombo’s twin European and Japanese orbiters to enter Mercury orbit, beginning the next global study of the planet’s oversized metallic core and tectonic surface.
85% of Mercury’s radius is metallic core, and scientists want BepiColombo’s gravity, magnetic, topographic and imaging data to refine estimates of that layered interior and the thickness of its rocky shell.
Up to 7 kilometers of planetary contraction inferred from MESSENGER data helps explain Mercury’s long curved scarps—some rising more than 1.5 kilometers—as the crust was compressed over a cooling interior.
About 6,000 ridges and scarps were mapped by MESSENGER, while later studies found 190 small grabens that may be 300 million years old or younger, hinting contraction may have continued into geologically recent times.
No seismometer has yet recorded a Mercury-quake, so BepiColombo’s broader significance is testing whether the Solar System’s smallest planet is still adjusting to its metal-rich interior.