The BepiColombo spacecraft, operated by the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA), could feel the heat even before it reaches its destination: Mercury. Due to a breakdown, the spacecraft’s engines no longer work at full power. The team still needs to determine how this will affect upcoming maneuvers, such as a flyby of Mercury planned later this year.
BepiColombo is scheduled to become only the second mission to orbit Mercury in December 2025. It consists of two probes and a so-called “Mercury transfer module,” which scientists hope will answer many puzzling questions about our solar system’s smallest planet. (To be clear, BepiColombo has already conducted flybys of Mercury, but has not yet entered Mercury’s orbit.)
These questions include questions like how Mercury can be so scorching hot and still have ice in its polar craters, why the planet has a weak magnetic field, and what the mysterious cavities on its surface are.
The 48 million mile (77 million kilometer) journey to Mercury is anything but easy for BepiColombo; The spacecraft will conduct a total of nine planetary flybys before inserting into the orbit of the relatively small planet. And as ESA reports, the spacecraft’s mishap on April 26 made this journey even more complicated.
Related: A cursory visit to BepiColombo shows that Venus is leaking carbon and oxygen
BepiColombo, which launched from the ESA launch facility in Kourou, French Guiana on October 20, 2018 aboard an Ariane 5 rocket, experienced the mishap as it prepared to carry out a maneuver in space should prepare for its fourth flyby of Mercury on September 5, 2024.
The Mercury Transfer Module is equipped with solar systems and an electric propulsion system to generate thrust. However, as the spacecraft was about to begin its maneuver on April 26, operators discovered that the transfer module was unable to supply sufficient electrical energy to its engines.
Once the error was identified, ESA operators set about fixing it. By May 7, the team had restored power to the engines so that they were at 90% of their full capacity, but the power available from the Mercury Transfer Module is still below what it should be. This means that BepiColombo will continue to operate without full thrust.
ESA said the BepiColombo team’s main priorities at the moment are keeping the spacecraft’s thrust stable at its current suboptimal level and figuring out how the spacecraft will handle upcoming maneuvers at less than full propulsion. Operators are also working to determine the cause of the loss of performance and assess whether full performance can actually be restored.
During its journey to Mercury, BepiColombo completed one flyby of Earth on April 10, 2020 and two flybys of Venus on October 15, 2020 and August 10, 2021. During these later flybys, the spacecraft collected important scientific data about Venus. This is the second planet from the Sun and the hottest planet in the solar system.
BepiColombo made its first Mercury flyby on October 1, 2021, with the second and third flybys following on June 23, 2022 and June 19, 2023. As mentioned above, the fourth Mercury flyby is scheduled for September 5 this year. with a fifth and sixth flyby of the first planet from sunset on December 2, 2024 and January 9, 2025.
ESA has not yet announced whether and how the engine failure will affect these operations or the overall schedule of the mission, which is scheduled to end on May 1, 2028, after BepiColumbo has spent ten Mercury years in orbit around the tiny planet.