ESA’s BepiColombo completes epic 8-year, 6-billion-mile journey to Mercury
The European Space Agency marked the successful arrival of its BepiColombo mission to Mercury on September 3, just the third spacecraft to ever visit our solar system’s innermost planet.
Despite being so close to Earth, it takes roughly as much time to arrive in orbit around Mercury as it would to arrive at Pluto: more than 8 years. Given the intense gravitational pull of the Sun, any attempt at keeping a flat, straightforward course is impossible without substantial propulsion equipment unsuitable for a science probe like BepiColombo.
Instead, the craft had to rely on constant flybys of other planets, whose gravity could help to apply the brakes. Nine were completed in total en route to Mercury, which had to be approached at a Goldilocks velocity — too fast and the probe would fly right past it, too slow and it would drift permanently off course.
Against the odds, ESA successfully navigated 6 billion miles this way, and at noon local time from mission control in Darmstadt, Germany, the first arrival phase was completed to cheers.”BepiColombo’s Mercury Transfer Module (MTM) successfully separated from the spacecraft stack,” ESA wrote in a statement. “This landmark achievement for the ESA and Japan Aerospace Exploration Agency (JAXA) mission marks the first step of BepiColombo’s long-awaited arrival at Mercury.”The MTM contained a combination solar and gas propellant propulsion system that helped power it through the constant gravitational interference.
Having come within 1.8 million miles of Mercury, its job was done and the module was left to float away in a process which the agency described as “one of the most complex planetary arrival sequences ever attempted by ESA.””We heard it loud and clear in the voice loop from Flight Dynamics Manager, Frank Budnik, that they could clearly see from the Doppler data that MTM had separated. After all this waiting and preparation, we all looked at each other and hugged. It was a very powerful moment,” said Emmanuela Bordoni, ESA BepiColombo B-shift Spacecraft Operations Manager.
The results will offer unprecedented opportunities to study Mercury’s surface, interior, magnetic field, and surrounding environment when the two remaining science modules begin primary mission phases in April 2027.”Although we already have great science from the cruise phase and nine planet flybys, it’s fantastic that we’ve taken this first important step towards finally being able to use all the powerful instruments on both MPO and Mio to study Mercury,” said ESA BepiColombo Lead Project Scientist Geraint Jones.
