BepiColombo spacecraft prepare to separate and begin Mercury arrival phase
The ESA and JAXA orbiters will separate from their propulsion module on September 3, marking the start of a multi-month sequence culminating in their arrival at Mercury in late 2025.
What happened
The BepiColombo mission, launched in October 2018, is entering its arrival phase at Mercury on September 3, 2025. The two science orbiters—ESA's Mercury Planetary Orbiter (MPO) and JAXA's Mercury Magnetospheric Orbiter (MMO/Mio)—will separate from their power and propulsion module at approximately 8 a.m. EDT (1200 GMT), with signal acquisition expected by 9:53 a.m. EDT. The separation marks the beginning of a sequence in which the orbiters will be captured by Mercury's gravity on November 21, with Mio entering its final elliptical orbit on December 9 or 10 and MPO reaching its designated orbit on March 10, 2027. The science phase of the BepiColombo mission is scheduled to begin on April 6.
Context
BepiColombo's arrival ends a six-year journey to the inner solar system's least explored planet. The two orbiters will conduct complementary investigations: MPO will map Mercury's surface at multiple wavelengths to chart mineralogy, elemental composition, and interior structure, while Mio will study the planet's magnetosphere. Together, these investigations aim to answer fundamental questions about Mercury's composition, whether its interior is molten, and the extent and origin of its magnetic field. The mission's science phase will last at least one Earth year.