Solar wind magnetic field measurements from the sub-L1 point on the HENON CubeSat

HENON (Heliospheric pioneer for solar and interplanetary threats defence) is a new European CubeSat technology demonstration mission conceived to address the widely recognized space weather need for longer lead-time measurements of the solar wind upstream of the Earth. To do this, HENON will occupy a distant retrograde orbit in the Sun-Earth system, ‘orbiting’ the Earth once per year and spending a significant period of time upstream of the Earth at 0.1 AU distance, x10 that of the L1 point. Planned for launch in early 2027, HENON will carry a miniaturised space weather payload as a pathfinder to demonstrate increased warning times for space weather conditions at Earth. This payload includes a radiation monitor, a solar wind instrument, and a magnetometer, MAGIC.

In this contribution we present the MAGIC instrument that is being developed for HENON. MAGIC is highly miniaturised and based on magneto-resistive technology, making it a suitable instrument solution given the limited resource envelope on HENON. MAGIC’s flight heritage includes the CINEMA and RadCube CubeSats in low-Earth orbit, with a further version now delivered for flight as part of the ERSA payload planned for the Lunar Gateway. Here we describe the instrument concept and design, as well as the main technical developments arising from the implementation of MAGIC on HENON, most specifically in efforts to improve radiation hardness assurance.

Although HENON is conceived in the context of space weather monitoring, by measuring the solar wind magnetic field HENON-MAGIC will help advance our understanding of the solar wind and heliophysics more generally. We review key outstanding scientific questions relating to the solar wind that HENON will provide insight into, and summarise some previous observations that help inform the HENON science goals.