The Terzina payload on board the NUSES space mission

The Terzina payload, onboard the NUSES space mission is being built in collaboration with TAS-I by GSSI, INFN and the University of Geneva. It is a Cherenkov Schmidt-Cassegrain compact telescope with an effective focal length of 925~m and a camera focal assembly composed of 640 pixels (16 vertically and 40 horizontally) organized in 8x8 tiles produced by FBK with sensitive area 2.9x2.6 mm^2. We will illustrate the performance for the signal of cosmic rays beyond a threshold of few hundreds of PeV. Understanding the operation of SiPMs in space with almost direct exposure to solar and trapped protons and electrons, defining the mitigation strategy for the increase of DCR of exposed silicon, the characterisation of the luminous backgrounds, the data acquisition strategy for this payload, the maximization of the effective exposure to the atmospheric showers induced by the signal of neutrinos and cosmic rays are the challenges. At this conference, we describe how they are being addressed.