Only two spacecraft have ever visited Mercury — Mariner 10, which flew by in 1974 and 1795, and MESSENGER, which orbited more than 4,000 times before crashing onto the planet’s surface in 2015. Both of these were NASA missions. BepiColombo will be the first Mercury mission for both ESA and JAXA, and the scientists behind it hope to uncover some unique features about the largely unknown planet.
“Mercury plays a fundamental role in understanding the formation and evolution of our solar system,” Johannes Benkhoff, a project scientist at ESA, told Digital Trends. “Until recently, Mercury was the least known planet in the inner solar system and its precise characterization is long overdue.”
As a joint venture, BepiColombo boasts an unconventional “stacked aircraft” design, which consists of a transport module carrying one orbiter each for the European and Japanese agencies. The two orbiters will disjoin once they arrive at Mercury, before dipping into separate orbits.
Japan’s Mercury Magnetospheric Orbiter is designed to study the planet’s magnetosphere with five custom instruments, while ESA’s Mercury Planetary Orbiter is optimized for remote sensing of the planet’s surface with eleven instruments.
Getting the orbiters into position will be a challenge, as the planet basks in sunlight and radiation levels that would obliterate familiar lifeforms. The aircraft developer Airbus has coated the European orbiter with 50 layers of ceramics and aluminum insulation to shield it from these extreme temperatures.
To Benkoff, it’s worth the effort. “Studying Mercury fits very well into ESA’s program and our science goal,” he said. “We can also demonstrate international collaboration and our ability to do state of the art science and engineering.”
The mission will cost around $1.48 billion, including cooperation with 33 companies from twelve European Union nations, and companies in the United States and Japan.
The agencies plan to launch the module from Kourou in French Guiana on October 5, 2018. It is expected to arrive at Mercury on December 5, 2025.