NBI NEWS — March 13, 2026 — After a complex seven-year journey through the inner solar system, the joint European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) mission, BepiColombo, has begun its final approach to Mercury. The ambitious mission is on track for a critical orbit insertion in late 2026, setting the stage for an unprecedented dual-spacecraft investigation of the solar system’s innermost and least understood planet.
BepiColombo, named after the late Italian scientist Giuseppe “Bepi” Colombo who calculated the gravity-assist maneuver, is one of the most complex planetary missions ever undertaken. Its primary goal is to unravel the mysteries surrounding Mercury’s surprising magnetic field, unique core, and scorched surface, which paradoxically might contain water ice in permanently shadowed craters.
A Seven-Year, Gravity-Assisted Odyssey
Launched in October 2018, BepiColombo has navigated a tortuous path, utilizing nine planetary gravity assists—one with Earth, two with Venus, and six with Mercury itself—to brake against the Sun’s massive gravitational pull without expending enormous amounts of fuel.
The final Mercury flyby, scheduled for late 2026, will be the critical “slowdown” maneuver needed for orbit insertion. This complex “celestial billiards” game has required precise navigation, relying on electric ion propulsion for small corrections between the main gravitational interactions.
One Mission, Two Destinies: The Great Separation
The most unique aspect of BepiColombo is its architecture. It is not one spacecraft, but a composite stack that will separate upon arrival into two independent orbiters, each with distinct scientific objectives:
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MPO (Mercury Planetary Orbiter – ESA): This main orbiter will settle into a tight, polar orbit closer to the planet. It is designed to map the surface, analyze the internal structure and composition, and study Mercury’s thin exosphere. Its instruments will provide high-resolution imaging and geological maps with unprecedented detail.
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MMO (Mercury Magnetospheric Orbiter, ‘Mio’ – JAXA): This complementary orbiter will enter a more distant, elliptical orbit. Its primary focus is to investigate Mercury’s “magnetosphere”—the bubble of magnetic field that surrounds the planet, shielding it from the intense solar wind. The existence of this magnetic field, discovered by NASA’s Mariner 10, is still not fully understood.
By operating simultaneously in different orbits, the two spacecraft will provide the first-ever multipoint measurements of Mercury’s magnetic environment, a crucial step in understanding how planetary magnetospheres interact with the solar wind in the extreme conditions so close to a star.
Scientific Objectives: The Five Mysteries of Mercury
The combined mission aims to answer five fundamental questions that continue to baffle planetary scientists:
| Objective | Description | Why It Matters |
| Magnetic Field Origin | Determine the source of Mercury’s global magnetic field. | Understanding dynamic, liquid metal cores in terrestrial planets. |
| Volatiles in Shadow | Confirm the presence of water ice in permanently shadowed polar craters. | Investigating the distribution of life-essential compounds in the inner solar system. |
| Composition & Structure | Map the surface composition and determine the size of Mercury’s massive, iron-rich core. | Clues to how Mercury formed so dense and close to the Sun. |
| Exosphere & Magnetosphere | Study the dynamics of Mercury’s magnetosphere and its interaction with the solar wind and exosphere. | Insights into space weathering and magnetospheric physics in an extreme environment. |
| Test General Relativity | Perform precise radio science to test Einstein’s theory of gravity near the Sun’s mass. | Advancing our fundamental understanding of physics and gravity. |
Challenges of the Innermost World
Operating so close to the Sun, BepiColombo faces unprecedented challenges. The spacecraft will experience temperatures exceeding 350°C (660°F) on its sun-facing side, while its dark side drops to -180°C (-290°F). To survive this extreme gradient, the spacecraft are equipped with specialized thermal blankets, sunshields, and radiators.
Furthermore, the intense solar gravity makes precise navigation exceptionally difficult. The arrival in late 2026 must be executed with flawless precision to place both orbiters into their respective target orbits.
Global Collaboration for a Universal Goal
BepiColombo is a powerful example of international collaboration in space exploration, drawing on the expertise of scientists and engineers from across Europe and Japan. This mission embodies the global effort to expand our understanding of the solar system and our own planet’s history and future.
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