From WIRED · Ritsuko Kawai · · 1m 50s
BepiColombo finally reaches Mercury after 8 years
After a propulsion malfunction and a 6 billion mile journey, the joint European-Japanese probe is entering orbit around the solar system's most extreme planet.
In brief
After a propulsion malfunction and a 6 billion mile journey, the joint European-Japanese probe is entering orbit around the solar system's most extreme planet. BepiColombo's arrival at Mercury marks the first time two probes will simultaneously orbit the planet, enabling unprecedented study of its extreme conditions…
Eight year journey finally nearing end
BepiColombo was supposed to reach Mercury last year, but a propulsion malfunction forced a course change. After traveling 6 billion miles and eight years in space, the probe is now beginning its descent to low orbit.
Propulsion module separates successfully
On September 3, ground control confirmed the propulsion module separated from BepiColombo, marking the final phase of the European Space Agency and Japan Aerospace Exploration Agency mission. All systems reported smooth separation after the 200 million kilometer journey.
Why Mercury is so hard to reach
Mercury's proximity to the sun makes it extremely challenging to reach. Spacecraft must use massive amounts of fuel to slow down and avoid falling into the sun's gravity, or take a longer path using gravity assists from other planets.
Mercury's extreme temperature swings
Mercury's surface reaches over 800 degrees Fahrenheit during the day but plummets to minus 290 degrees at night. With virtually no atmosphere to regulate temperature, BepiColombo must survive these brutal daily extremes.
Two probes, one mission, new discoveries
BepiColombo will split into two spacecraft: the Mercury Planetary Orbiter to study the surface and interior, and the Mercury Magnetospheric Orbiter to investigate the magnetic field. This is the first time multiple probes will orbit Mercury simultaneously.
Key questions about Mercury await answers
Scientists hope to understand why Mercury has an oversized iron core, why ice exists in polar craters despite extreme heat, why it's the only rocky planet besides Earth with a magnetic field, and what causes mysterious surface depressions. Full observations begin in April 2027.
The short version
BepiColombo's arrival at Mercury marks the first time two probes will simultaneously orbit the planet, enabling unprecedented study of its extreme conditions and mysterious features.
