English: The JUpiter ICy moons Explorer (JUICE) is ESA's first mission to the outer solar system. It will carry a total of ten scientific experiments to study the gas giant Jupiter and three of its largest moons, Ganymede, Callisto and Europa. The mission was launched in April 2023 and its arrival at Jupiter will take place in 2031.

The J-MAG instrument is being developed for the JUICE mission by the J-MAG consortium, formed to implement, operate and exploit the magnetic field investigation on JUICE and led by Imperial College London (ICL). The J-MAG instrument consists of a very specific design with two fluxgate vector sensors and one scalar sensor with low absolute error. One of the fluxgate sensors and associated electronics are provided by ICL, the second fluxgate sensor and associated electronics are developed by the Technical University Braunschweig and the scalar sensor and associated electronics are provided by the Space Research Institute of the Austrian Academy of Sciences in Graz in close cooperation with the Institute of Experimental Physics of the Graz University of Technology.

The scalar sub-instrument (MAGSCA) is an optical magnetometer with low absolute error. The required accuracy of the J-MAG instrument can only be achieved when the fluxgate vector sensors are calibrated with the MAGSCA as baseline instrument.

https://www.oeaw.ac.at/en/iwf/research/space-missions/current-missions/juice/magsca