BepiColombo

BepiColombo
National Aeronautics and Space Administration (NASA) · Public domain · source
Name	BepiColombo
Mission type	Planetary science
Operator	European Space Agency / Japan Aerospace Exploration Agency
COSPAR ID	2018-080A
SATCAT	43688
Launch date	20 October 2018
Launch vehicle	Ariane 5
Launch site	Guiana Space Centre
Orbit target	Mercury
Spacecraft bus	MPO / Mio
Mass	~4100 kg (stacked)

BepiColombo is a joint European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA) robotic mission to Mercury, launched by an Ariane 5 from the Guiana Space Centre in 2018. The mission comprises a European-built Mercury Planetary Orbiter and a Japanese-built Mercury Magnetospheric Orbiter, plus a propulsion module, undertaking a complex interplanetary cruise with multiple gravity assists to enter orbit around Mercury and perform coordinated investigations of surface, interior, exosphere, and magnetosphere. The project is named after Giuseppe "Bepi" Colombo in recognition of his work on planetary dynamics and resonances involving Mercury and Venus.

Mission overview

The mission originated from proposals developed within ESA and JAXA programs during the late 20th and early 21st centuries, following precursor missions such as Mariner 10 and MESSENGER. Management and scientific leadership bring together teams from institutions including European Space Research and Technology Centre, European Southern Observatory, National Institute of Astrophysics (Italy), Max Planck Institute for Solar System Research, Institut d'Astrophysique Spatiale, Istituto Nazionale di Astrofisica, National Astronomical Observatory of Japan, and University of Tokyo. Industrial prime contractors include Airbus Defence and Space, Thales Alenia Space, and OHB SE partners. The integrated mission seeks to build on discoveries by MESSENGER and to coordinate with contemporaneous missions such as Parker Solar Probe, Solar Orbiter, and ground facilities like Arecibo Observatory (before its collapse) and Very Large Telescope for complementary studies.

Spacecraft design

The stack consists of the European Mercury Planetary Orbiter (MPO), the Japanese Mercury Magnetospheric Orbiter (MMO, "Mio"), and the European-provided Mercury Transfer Module (MTM). MPO is built on the PRIMA heritage platform and incorporates thermal protection similar to concepts tested on Venus Express and Rosetta. MMO leverages designs from Akatsuki and heritage from Nozomi. Propulsion uses a combination of chemical propulsion and solar electric propulsion informed by technologies from SMART-1, Hayabusa, and Dawn. The thermal shield architecture employs materials and coatings developed with partners including Italian Space Agency and German Aerospace Center. Communications utilize X-band and Ka-band transponders compatible with Deep Space Network, European Space Operations Centre, and Usuda Deep Space Center facilities. Attitude control and guidance reference systems include star trackers akin to those on Gaia and reaction wheels like units flown on Hubble Space Telescope servicing missions.

Scientific objectives and instruments

Primary objectives target Mercury's interior structure, crustal composition, magnetospheric dynamics, exospheric sources, and surface geology, complementing analyses performed by MESSENGER and telescopic studies from Hubble Space Telescope and Chandra X-ray Observatory. MPO carries instruments including a spectrometer suite with heritage from Mars Express and Venus Express missions, a gamma-ray and neutron spectrometer related to instruments on Lunar Reconnaissance Orbiter, a laser altimeter comparable to MOLA, and high-resolution imagers similar to cameras on Rosetta and Cassini–Huygens. MMO hosts magnetometers and plasma instruments built using designs from GEOTAIL, Cluster, and THEMIS, aiming to study Mercury's magnetosphere and coupling with the solar wind measured by Solar Orbiter and Parker Solar Probe. Collaborative payloads and calibration involve scientists from Universidad Nacional Autónoma de México, University of Leicester, Max Planck Institute for Solar System Research, ISAS, and Czech Academy of Sciences.

Cruise, trajectory, and operations

The trajectory uses a series of gravity assists at Earth, Venus, and Mercury, employing resonant flybys as analyzed by Giuseppe "Bepi" Colombo and leveraging navigation strategies refined during Cassini–Huygens and MESSENGER missions. The cruise phase included flybys of Earth (2019), Venus (2020, 2021), and multiple Mercury flybys to adjust velocity and inclination, coordinated through ESOC and ISAS flight dynamics teams. Operations make use of the European Space Tracking network and JAXA ground stations including Usuda Deep Space Center with planning support from European Space Agency Mission Control and the JAXA Electromagnetic Propulsion Laboratory. Thermal and power management during perihelion passages exploits lessons learned from MESSENGER operations and research from Solar Orbiter teams.

Mercury orbital phases and science results

On arrival the MPO entered a series of capture maneuvers to achieve a polar Mercury orbit for global mapping, while MMO aimed for an equatorial magnetospheric orbit to monitor space weather interactions, paralleling measurements by Mariner 10 and MESSENGER. Early science returned insights into crustal magnetization, surface volatile distributions comparable to lunar polar ice studies by Lunar Reconnaissance Orbiter, and confirmations or revisions of models proposed by researchers at Brown University, MIT, Caltech, ETH Zurich, and University of Arizona. Magnetospheric observations link to phenomena studied by Cluster and MMS, revealing reconnection and particle acceleration processes tied to inputs from Parker Solar Probe solar wind characterizations. Spectroscopic mapping informs comparative planetology with Mars, Venus, and Moon research communities hosted at NASA Goddard Space Flight Center and JPL.

Mission legacy and future prospects

BepiColombo's integrated European–Japanese collaboration establishes precedents for international planetary missions following in the footsteps of Cassini–Huygens, Rosetta, and Hayabusa2, influencing planning at NASA, ESA Science Programme, JAXA, and research centers such as Max Planck Institute for Solar System Research and Smithsonian Astrophysical Observatory. Technological legacies include advances in thermal protection, electric propulsion, radiation-hardened electronics, and coordinated multi-spacecraft operations informing missions like JUICE, MMX, and proposed Mercury sample-return concepts debated at International Astronautical Congress sessions. Scientific datasets are archived in facilities like Planetary Data System and PSA, enabling comparative studies by universities including University of Colorado Boulder, University of Oxford, Imperial College London, and Tohoku University. The mission paves the way for future exploration of innermost planets, instrument miniaturization, and collaborative frameworks between major space agencies at international meetings such as COSPAR and IAC.

Category:Planetary spacecraft