BepiColombo, mankind's third mission to the hellish planet Mercury, blasted off Oct. 20 on a seven-year-long journey that should allow scientists to learn more about the formation of our Solar System. Mercury lies only 60 million miles from the Sun.
A joint effort of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA), BepiColombo comprises two satellites. These sats -- the Mercury Planetary Orbiter or MPO (nicknamed Bepi) and Mio (Mercury Magnetospheric Orbiter, or MMO) -- will be launched towards the planet once the spacecraft establishes Mercury orbit.
Bepi was developed by ESA while JAXA built Mio. The BepiColombo spacecraft and its two "passengers" should arrive at Mercury in December 2025.
The BepiColombo mission will perform mankind's most comprehensive study of Mercury to date. It will study the planet's magnetic field, magnetosphere, interior structure, and surface. To establish orbit, Mercury, BepiColombo will have to make a flyby of Earth; two flybys of Venus, and six flybys of Mercury.
The $1.5 billion mission was approved in November 2009, is the last mission of ESA's Horizon 2000+ program to be launched.
The spacecraft is named after Italian scientist Giuseppe Colombo, whose nickname is Bepi. This scientist, mathematician, and engineer from Italy was the first to implement the interplanetary gravity-assist maneuver during the 1973 Mariner 10 mission. Mariner 10 flew past Mercury and Venus and studied both these searing inner planets.
ESA says the mission is one of the most challenging in its history. Mercury's extreme temperatures; the massive gravitational pull exerted by the Sun and destructive solar radiation make for hellish conditions that will severely challenge BepiColombo's hardened technologies.
The same hardening went into the design of Bepi and Mio. Both probes are designed to cope with temperatures ranging from 430 degrees Celsius on the side facing the Sun, too -180 degrees Celsius in Mercury's shadow.
Bepi will operate in Mercury's inner orbit, while Mio will stay in the outer orbit to gather data that should reveal the internal structure of Mercury, its surface and geological evolution.
Mercury's surface temperatures vary diurnally and range from 173°C at night to 427°C during the day across the equatorial regions. The Polar Regions are constantly below -93°C.
Scientists hope to build on the insights gained by NASA's Messenger probe, which shut down in 2015 after a four-year studying Mercury. The only other spacecraft to get to Mercury was Mariner 10.
Beyond completing the challenging journey, this mission will return a huge bounty of science, said Johann-Dietrich Wörner, ESA Director General.
JAXA President Hiroshi Yamakawa said his agency has high expectations that the forthcoming detailed observations of Mercury will help scientists better understand the environment of the planet. These observations will ultimately lead to more clues about the origin of the Solar System, including that of Earth.
