The 2.5 m long boom carrying the magnetometer sensors onboard ESA’s BepiColombo Mercury Planetary Orbiter (MPO) has been successfully deployed. The sensors are now prepared to measure the magnetic field on the way to Mercury. Moreover, they have already returned their first data – recording the magnetic field change as the boom moved away from the slightly magnetized body of the spacecraft into its deployed position.
Until 12:40 UTC (12: 40 GMT or 14:40 CEST), the graph shows the intrinsic spacecraft magnetic field as measured by the boom’s sensors. At the moment the boom deployment started, the fields decay with distance from the spacecraft, until the boom is fully deployed at 12:41 UTC. The three lines represent the strength of the magnetic field from the outboard sensor in the three directions of space.
The sensors will measure the solar wind on its way to Mercury. Two boom-mounted sensors with different distances to the spacecraft (indicated in the green circle in the right sub-image) will be used to distinguish between natural magnetic fields and intrinsic stray fields.
At the same time, one of the monitoring cameras onboard the Mercury Transfer Module imaged the deployment, which took about one minute.
Once at Mercury, the magnetometer will measure the planet’s magnetic field, the interaction of the solar wind, and the formation and dynamics of the magnetosphere – the magnetic ‘bubble’ around the planet. Together with measurements captured by a similar instrument suite onboard JAXA’s Mercury Magnetospheric Orbiter, the spacecraft will provide scientists with data that will help investigate the dynamic environment of the planet, as well as the origin, evolution and current state of the planet’s magnetic field and its interior.
BepiColombo is a joint endeavour between ESA and the Japan Aerospace Exploration Agency, JAXA. It is the first European mission to Mercury, the smallest and least explored planet in the inner Solar System, and the first to send two spacecraft to make complementary measurements of the planet and its dynamic environment at the same time.