Solar wind monitor for space weather forecasting and science at 0.9 AU – HENON mission

The HEliospheric pioNeer for sOlar and interplanetary threats defeNce (HENON) mission is being developed in the framework of the ESA General Support Technology Program (GSTP) Fly Element and funded by the Italian Space Agency. Currently it is in the middle of implementation stage (Phase D), expected to be launched as a companion of the ESA Plato spacecraft in January 2027. In several months using its own innovative solar-electric propulsion, the 12U cubesat will transfer to a Distant Retrograde Orbit (DRO) of the Sun-Earth system. The one-year lasting orbit allows for about three months to stay ~ 0.1 AU in front of the Earth. Such a unique vantage point enables the quasi real time monitoring of the particle radiation environment in deep space and the generation of alerts for geoeffective solar wind structures several hours before they can reach the Earth. During the rest of the orbit the HENON cubesat will make scientific observations of large solar wind structures and study the fundamental processes of space plasma physics including the particle acceleration and turbulence. The mission payload consists of the high-resolution radiation monitor (REPE), magnetometer (MAGIC), and the Faraday cup based solar wind monitor (FCA), provided by the Italian, Finnish, UK, and Czech consortium members.

 

We report on a development progress of latter sensor – the Faraday Cup Analyzer (FCA), devised at Charles University as a simple and robust sensor for long-term monitoring of the basic solar wind parameters – density, velocity and temperature. The FCA flight unit currently undergoes environmental and functional testing. As the HENON mission is greatly constrained with limited spacecraft telemetry, we also discuss the data strategy and on-board data processing allowing maximum scientific income and satisfying the mission requirements. The instrument operation modes and telemetry data products are described.