What is FOXSI?
The Focusing Optics X-ray Solar Imager (FOXSI) is a sub-orbital rocket project with four successful launches (and gearing up for a fifth in winter/spring 2025-2026!) It is the first solar-dedicated instrument to observe hard X-rays using focusing optics. Direct imaging enables the experiment to study solar X-ray radiation with enhanced sensitivity and dynamic range, exploring issues of energy release and particle acceleration in the corona—the outermost layer of the Sun.
FOXSI-4
The rocket’s fourth launch successfully occurred in April 2024 at Poker Flat Research Range in Alaska as part of NASA's first-ever solar flare campaign. Hi-C and FOXSI-4 observed an M1 class solar flare simultaneously.