Relativistic Electron and Proton Experiment for the HENON mission: simulated performance




Ngom, Catherine; Oleynik, Philipp; Virtanen, Pasi; Raukunen, Osku; Peltonen, Juhani; Peltola, Tatu; Säntti, Tero; Punkkinen, Risto; Punkkinen, Arttu; Anantha Raman, Deepa; Lehti, Jussi; Marcucci, Maria Federica; Laurenza, Monica; Vainio, Rami

PublisherEDP Sciences

2026

 Journal of Space Weather and Space Climate

9

16

2115-7251

DOIhttps://doi.org/10.1051/swsc/2026002

https://doi.org/10.1051/swsc/2026002

https://research.utu.fi/converis/portal/detail/Publication/523410303



HEliospheric pioNeer for sOlar and interplanetary threats defeNce (HENON) is a 12U CubeSat that will explore for the first time ever the Distant Retrograde Orbit in the Sun-Earth system, bringing a payload suited for Space Weather observations and science. Initially designed for the Foresail-2 nanosatellite mission, the Relativistic Electron and Proton Experiment (REPE) instrument has since evolved for deployment in a variety of future missions, including the HENON mission. REPE is a particle telescope developed to measure fluxes of high-energy electrons and protons over broad ranges of energies, relevant to the space radiation environment. The instrument is designed to measure electron energy spectrum from 0.1 to 10.4 MeV and proton energy spectrum from 2 to hundreds of MeV. We present Monte Carlo simulations of REPE performance using Geant4. We evaluate the performance in terms of sensitivity (geometric factor), energy resolution, and cross-contamination between measured species. We show that the instrument meets the scientific requirements of the mission.


We gratefully acknowledge the use of SOHO/EPHIN electron observations as input to our simulation studies. SOHO is an international project of collaboration between ESA and NASA. We also acknowledge the use of ESA’s SEPEM Reference Data Set version 3.0 (produced under the following ESA Contracts: 20162/06/NL/JD; 4000108377/12/NL/AK; 4000107025/12/NL/AK; 4000115930/15/NL/HK, 4000127129/19/NL/HK, 4000127282/19/NL/IB/gg). We acknowledge the Heliospheric Pioneer for Solar and Interplanetary Threats Defence (HENON) mission Phase A/B and C. HENON is part of the Italian Space Agency (ASI) program Alcor and is being developed under the European Space Agency General Support Technology Programme (ESA-GSTP) through the support of the national delegations of Italy (ASI), UK, Finland, and the Czech Republic. The views expressed herein can in no way be taken to reflect the official opinion of ESA. M.F.M. and M.L. acknowledge the Space It Up project of ASI and the Ministry of University and Research, MUR, contract n. 2024-5-E.0 – CUP n. I53D24000060005. The work in the University of Turku was carried out under the umbrella of Finnish Centre of Excellence in Research of Sustainable Space (FORESAIL, Research Council of Finland, decision 352847). We gratefully acknowledge also the Proof of Concept funding from the Research Council of Finland (RADICS, decision 359530). The editor thanks Fan Lei and an anonymous reviewer for their assistance in evaluating this paper.


Last updated on 18/05/2026 11:30:49 AM