The BepiColombo spacecraft, a joint mission operated by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA), is experiencing complications as it journeys towards Mercury. Recently, the spacecraft’s thrusters have encountered a glitch, reducing their power output. This issue poses potential challenges for the mission, particularly for the upcoming flybys and its eventual orbit insertion around Mercury later this year.
Launched on October 20, 2018, BepiColombo is the second mission aiming to orbit Mercury, with an anticipated arrival in Mercury’s orbit by December 2025. The mission comprises two probes: the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). These probes are expected to address several enigmatic aspects of Mercury, including its extreme temperatures, the presence of ice in its polar craters, its weak magnetic field, and the mysterious surface hollows.
The spacecraft’s journey to Mercury spans 77 million kilometers and is far from straightforward. It involves nine planetary flybys to leverage gravitational assists for trajectory adjustments. To date, BepiColombo has successfully executed a flyby of Earth on April 10, 2020, and two flybys of Venus on October 15, 2020, and August 10, 2021. During these Venus flybys, the spacecraft gathered significant scientific data about the planet, which is the second planet from the sun and the hottest in the solar system.
BepiColombo also completed three flybys of Mercury on October 1, 2021, June 23, 2022, and June 19, 2023. The fourth flyby is scheduled for September 5, 2024, with additional flybys planned for December 2, 2024, and January 9, 2025. These maneuvers are crucial for the spacecraft to adjust its path and reduce speed for a successful orbit insertion around Mercury.
The recent glitch occurred as BepiColombo was preparing for a maneuver to set up its fourth Mercury flyby. The Mercury Transfer Module (MTM), which houses solar arrays and an electric propulsion system, failed to deliver sufficient electrical power to the thrusters. This resulted in the spacecraft operating with less than optimal thrust.
Upon identifying the fault, ESA operators promptly initiated corrective measures. By May 7, the team managed to restore power to the thrusters, achieving 90% of their full capacity. Despite this partial recovery, the power output remains below the required level, meaning BepiColombo continues to function without its full thrust capability.
The primary concern for the BepiColombo team is maintaining the spacecraft’s thrust stability at its current sub-optimal level. They are also focused on evaluating how the reduced thrust will impact upcoming maneuvers and whether full power can be restored. Determining the cause of the power drop and devising a solution are critical tasks currently underway.
The spacecraft’s journey and scientific objectives are significant. Mercury, being the smallest planet in our solar system, presents numerous scientific puzzles. One key question is how the planet can endure such high temperatures and still retain ice within its polar craters. Additionally, understanding Mercury’s weak magnetic field and the origins of the mysterious hollows on its surface are central to the mission’s scientific goals.
BepiColombo’s data collection during its journey has already contributed valuable insights. For example, observations of Venus provided crucial information about its atmospheric composition and surface conditions, enhancing our understanding of this neighboring planet.
As BepiColombo approaches its fourth flyby of Mercury, the mission team remains vigilant in managing the thruster issue. ESA has not yet disclosed whether the glitch will significantly affect the planned flybys or the overall mission timeline, which aims to conclude on May 1, 2028. By that time, BepiColombo will have spent a decade orbiting Mercury, providing an unprecedented wealth of data about the innermost planet in our solar system.
The mission’s success hinges on overcoming the current technical challenges. With ongoing efforts to restore full thruster functionality and adapt to the current limitations, the BepiColombo team remains committed to achieving its scientific objectives and expanding our understanding of Mercury and the broader solar system.
