BepiColombo - Status and next Activities

Mercury is in many ways a very different planet from what scientist were expecting. Further spacecraft investigations are essential to better understand this mysterious planet. On 20 October 2018 the BepiColombo spacecraft was launched from the European spaceport in French Guyana and started its 7-year journey to the innermost terrestrial planet to obtain new investigations on the fundamental questions about its evolution, composition, interior, magnetosphere, and exosphere. BepiColombo a joint project between the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA) consists of two orbiters, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MIO).

The BepiColombo spacecraft is on its way to Mercury is in a so-called 'stacked' configuration: The MIO and the MPO are connected to each other, and stacked on-top of the Mercury Transfer Module (MTM). Only in late 2025, the 'stack' configuration is abandoned and the individual elements spacecraft are brought in to their final Mercury orbit: 480x1500km for MPO, and 590x11640km for MIO. Until then, BepiColombo has several opportunities for scientific observations - during the cruise and during nine flybys (one at Earth, two at Venus and six at Mercury). However, since the spacecraft is in this stacked configuration during the flybys only some of the below mentioned instruments will perform scientific observations on a best effort basis.

Recently the Near-Earth payload commissioning has been finished. In a first 3 months period after launch all payload on the MPO and MIO have been activated and checked. Some of the instruments has been already operated regularly in their "scientific" observation mode: the magnetometer (MPO-MAG), the accelerometer (ISA), the environmental sensor (BERM), the gamma-ray and neutron spectrometer (MGNS), and the solar intensity x-ray and particle spectrometer (SIXS). Others, like the radio science experiment (MORE), using the X-band and the Ka-band, the thermal infrared spectrometer (MERTIS), and the UV spectrometer (PHEBUS) are prepared to be operational during some solar conjunction experiments and the upcoming flybys at Earth and Venus, respectively. In a second period of the Near-Earth Commissioning the "high-voltage" instruments including instruments on MIO will be commissioned and it is expected to have some of them also scientific operational for the upcoming Venus flybys. Other instruments such as cameras and NIR spectrometer (SIMBIO-SYS), the laser altimeter (BELA), the x-ray spectrometer (MIXS), and the electron, neutron, and iron sensors of SERENA are operational, but can only be used in their scientific modes after the Mercury in-orbit commissioning in early 2026 because their field of view is blocked by the underlying Transfer Module.

The two commissioning phases were interrupted by the so called first "thrust arc" of the spacecraft. BepiColombo on its route to Mercury is propelled by a solar electric propulsion system. A second "thrust arc" is foreseen from September to November 2019 and sets the spacecraft into the right conditions to successfully perform the first Earth flyby in April 2020.

Once inserted into its orbits, the scientific payload of both spacecraft will provide the detailed information necessary to understand Mercury and its Magnetospheric environment and to find clues to the origin and evolution of a planet close to its parent star. The BepiColombo mission will complement and follow up the work of NASA's MESSENGER mission by providing a highly accurate and comprehensive set of observations of Mercury. In addition, the BepiColombo mission will provide a rare opportunity to collect multi-point measurements in a planetary environment. This will be particularly important at Mercury because of short temporal and spatial scales in the Mercury's environment. The foreseen orbits of the MPO and MIO will allow close encounters of the two spacecraft throughout the mission. The mission has been named in honor of Giuseppe (Bepi) Colombo (1920-1984), who was a brilliant Italian mathematician, who made many significant contributions to planetary research and celestial mechanics.