ESA's BepiColombo spacecraft begins autonomous separation en route to Mercury
The joint European-Japanese BepiColombo mission started its final approach to Mercury, successfully separating its two orbiters after an eight-year, 10-billion-kilometre journey.
The BepiColombo spacecraft, carrying the European Mercury Planetary Orbiter and Japan's Mio magnetospheric probe, entered the most challenging phase of its Mercury arrival on Thursday. After launching from Earth in 2018 and completing a series of nine gravity-assist flybys, the combined probe began an autonomous separation from its transfer module, a step required before the final descent toward the planet.
ESA mission manager Santa Martinez described the effort as "very ambitious," noting that Mercury’s weak gravity and proximity to the Sun make precise navigation essential. "It’s a tricky business," said Ignacio Tanco, head of inner solar system mission operations, referring to the 30-minute communication delay that forces the spacecraft to act without real-time ground control.
The separation was executed automatically: four struts were released and spring mechanisms pushed the two orbiters apart at about 40 cm per second. Confirmation of the maneuver arrived at ESA’s control centre in Darmstadt nearly two hours later, prompting applause among staff.
The probes are slated to enter Mercury’s orbit on 21 November, with a subsequent split into separate trajectories on 9-10 December. The Mercury Planetary Orbiter will later fly within 480 metres of the surface, while Mio will study the planet’s magnetic environment from an elliptical orbit extending up to 11 kilometres.
BepiColombo follows earlier missions such as NASA’s Mariner 10 and MESSENGER, aiming to resolve outstanding questions about Mercury’s magnetic field, core composition and surface features.