The scientific payload of LIGHT-1: A 3U CubeSat mission for the detection of Terrestrial Gamma-ray Flashes

Terrestrial Gamma-ray Flashes (TGFs) represent the most intense and energetic natural emission of gamma rays from our planet. TGFs consist of sub-millisecond bursts of gamma rays (energy up to one hundred MeV) generated during powerful thunderstorms by lightnings (average ignition altitude of about 10 km). Such bursts of gamma-rays are in general companions of several other counterparts (electron beams, neutrons, radio waves). The TGF ideal observatory is a fast detector with spectral abilities operating in Low Earth Orbit (LEO). Conceived to these specifications, the LIGHT-1 3U CubeSat mission was launched on December 21st, 2021 and deployed from the International Space Station (ISS) on February 3rd, 2022 with the aim of targeting TGFs. In this paper the detailed structure of the payload, its main detection features, and the first flight data are presented.