BepiColombo’s Unexpected Detour: A Year-Long Delay to Unlock Mercury’s Secrets
The European Space Agency’s (ESA) ambitious mission to Mercury, BepiColombo, is facing a significant setback. After encountering an unforeseen glitch in its propulsion system, the spacecraft’s journey to the innermost planet has been extended by nearly a year.
Originally scheduled to enter Mercury’s orbit in December 2025, BepiColombo will now arrive in November 2026. This delay stems from an issue with the spacecraft’s Transfer Module, which is responsible for generating thrust. During a scheduled maneuver on April 26th, the module failed to provide sufficient electrical power to the thrusters.
"It’s so exciting that BepiColombo can boost our understanding and knowledge of Mercury during these brief flybys, despite being in ‘stacked’ cruise configuration,” stated Johannes Benkhoff, BepiColombo project scientist. “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, while also getting a head start on preparations to make sure we will transition into the main science mission as quickly and smoothly as possible.”
Following a thorough investigation, engineers determined that "unexpected electric currents" arose between BepiColombo’s solar array and the unit responsible for power distribution. This resulted in a persistent reduction in electrical power to the thrusters, making the original 2025 arrival impossible.
However, the ESA team has devised an ingenious solution. BepiColombo will now follow a modified trajectory, taking it closer to Mercury’s surface than initially planned. This new route allows the spacecraft to utilize lower thrust during its cruise phase, ultimately enabling it to reach its destination.
The revised flight path will also offer an unprecedented opportunity for scientific observation. On Thursday, BepiColombo is scheduled to fly by Mercury, coming within 35 kilometers of its surface. This will be the first time the spacecraft flies over Mercury’s poles, providing valuable data and allowing for an adjustment of its trajectory to match the planet’s orbit.
Beyond its scientific significance, this close encounter will also offer breathtaking views of Mercury’s south pole, images that are eagerly anticipated by the scientific community.
BepiColombo is a collaborative mission between ESA and the Japan Aerospace Exploration Agency (JAXA). It comprises two orbiters: ESA’s Mercury Planet Orbiter (MPO), designed to study Mercury’s surface and internal structure, and JAXA’s Mercury Magnetosphere Orbiter (MMO), dedicated to investigating the planet’s magnetic field.
Launched in October 2018, BepiColombo has already completed its first Mercury flyby in October 2021, delivering stunning images of the solar system’s smallest planet. This journey is not a straight shot to Mercury; the spacecraft navigates a complex series of gravity assists, maneuvering around Earth, Venus, and Mercury itself. A total of nine flybys are planned: one around Earth, two around Venus, and six around Mercury.
Mercury, despite its proximity to the Sun, remains one of the least explored planets in our solar system. Its enigmatic nature, driven by the Sun’s powerful gravitational pull, presents unique challenges for spacecraft reaching its surface.
The mission aims to unravel many of Mercury’s mysteries, including:
- Its composition and formation: How did Mercury, the smallest rocky planet, come to exist? What is it made of?
- Its magnetic field: How does Mercury, a relatively small planet, generate a magnetic field that rivals Earth’s?
- The evolution of its surface: What processes have shaped Mercury’s scarred and cratered landscape?
- Its internal structure: What lies beneath the planet’s surface?
BepiColombo‘s journey to Mercury is a testament to human ingenuity and scientific ambition. Despite the unexpected delay, the mission remains poised to unlock the secrets of this enigmatic planet, expanding our understanding of our solar system and the processes that shaped it. As the spacecraft embarks on its final leg of the journey, scientists and space enthusiasts alike hold their breath, eager to witness the unveiling of Mercury’s hidden treasures.
