CSES (China Seismo-Electromagnetic Satellite) is a sophisticated multi-payload space observatory aimed to the observation of the Van Allen Belts dynamics, the study of solar-terrestrial interactions and the extension at low energies of existing Cosmic Ray measurements. The first satellite (CSES-01) is on orbit since February 2018, hosting on board the HEPD-01 particle detector. The second (CSES-02) will be launched during the early 2024, and will carry HEPD-02, a new high energy particle detector. HEPD-02 is optimized to detect charged particles: mostly electrons (3-100 MeV) and protons (30-200 MeV), with good capabilities in the identification of heavier nuclei. The instrument is quite compact (40.36cm x 53.00cm x 38.15cm) and presents important upgrades with respect to its predecessor: it will be the first instrument carrying a CMOS pixel tracker in space, designed to reach a 5 micron resolution; it will mount an electromagnetic calorimeter that includes six of the largest LYSO crystals ever used in space (15cm x 5cm x 2.5cm). The full detector has been recently integrated, with an event reconstruction software already in place. A detailed Monte Carlo (MC) simulation was developed and an extensive test beam campaign performed to validate HEPD-02 capabilities in identification and measurement of kinetic energy and arrival direction of incoming particles. In this contribution a synthetic description of the HEPD-02 detector and its main characteristics will be given. The estimation of its scientific performances on MC simulation will be reported, with a particular focus on their assessment with the different test beam acquisitions and atmospheric muon data.