Thruster Issues Delay BepiColombo Probe's Mercury Arrival Until November 2026
The European-Japanese BepiColombo spacecraft will face a delay in its mission to Mercury due to thruster issues, pushing its expected arrival at the innermost planet to November 2026. The spacecraft, which launched in 2018, was initially scheduled to enter Mercury's orbit in December 2025, but complications with its propulsion system have forced a revision of its trajectory.
Details of the Glitch
In April 2024, BepiColombo encountered a problem with its thrusters, which has since been traced to unexpected electric currents between the spacecraft’s Mercury Transfer Module (MTM) solar array and its power distribution unit. As a result, the MTM’s electric thrusters are operating below the necessary power levels needed for the planned orbital insertion.
Santa Martinez, ESA's BepiColombo mission manager, explained in a statement on September 2, “Following months of investigations, we have concluded that MTM's electric thrusters will remain operating below the minimum thrust required for an insertion into orbit around Mercury in December 2025.”
New Trajectory and Mission Impact
Despite the setback, ESA's Flight Dynamics team has developed a workaround. The spacecraft will now follow a revised trajectory that will bring it about 22 miles (35 kilometers) closer to Mercury than initially planned. This adjustment will reduce the thrust needed for the fifth flyby and alter the spacecraft’s path to ensure it reaches Mercury in November 2026.
Johannes Benkhoff, BepiColombo project scientist, remains optimistic about the mission’s long-term goals. “We get to fly our world-class science laboratory through diverse and unexplored parts of Mercury’s environment that we won’t have access to once in orbit,” he said. The spacecraft’s main scientific observations will commence once the ESA and JAXA orbiters separate and begin their dedicated studies of Mercury.
Mission Details
BepiColombo, a joint mission between the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA), is designed to explore Mercury's surface, interior, and magnetic field. The spacecraft comprises two orbiters: ESA's Mercury Planetary Orbiter (MPO) and JAXA’s Mercury Magnetospheric Orbiter (MMO).
Each orbiter is equipped with a suite of 16 scientific instruments, and they will spend at least one year in orbit around Mercury, with the possibility of extending this period.
The spacecraft's upcoming flyby on September 4, 2024, will be its fourth close pass of Mercury. During this maneuver, BepiColombo will capture images of Mercury's surface using three monitoring cameras on the MTM, while its main science camera remains shielded until the orbiters separate.
Future Expectations
Although the delay is disappointing, it does not endanger the mission’s overall success. The revised trajectory will still allow BepiColombo to achieve its scientific objectives, providing valuable insights into Mercury’s composition and evolution.
The spacecraft’s new arrival timeline underscores the complexity and challenges of space exploration, particularly when operating near the Sun.
For ongoing updates and discussions about space missions, join the Space Forums and stay tuned for further developments on BepiColombo’s journey.