VERTECS: development status and system verification of flight model

Abstract

Extragalactic Background Light (EBL), the cumulative light from outside the Galaxy, is a crucial observational key for understanding the history of the universe. Previous observations have shown that the EBL in the near- infrared is several times brighter than the integrated galaxy light. Proposed origins include radiation from the early universe and intrahalo stars distributed within Galactic halos. Since these sources are expected to exhibit different spectral energy distribution in the visible band, the VERTECS (Visible Extragalactic background RadiaTion Exploration by CubeSat) mission aims to observe the visible EBL. The satellite consists of a 3U payload and a 3U bus module. The payload is composed of a wide-field telescope (6° × 6° FoV, F2, 70-mm focal length), a four-band (400–800 nm wavelength) optical filter set, and a low-dark-current CMOS sensor. The bus employs a platform previously developed in Kyutech along with Blue Canyon Technologies’ XACT-15 attitude control system to meet the pointing-stability requirement of ∠ 10′′/min (1σ), deployable solar array paddles from DHV Technologies to satisfy the power demand, and Addnics’ high-speed X-band transmitter for downlinking science data. Under the JAXA-SMASH program, the VERTECS project started 2022, and in 2025 we are conducting the assembly of the flight model (FM) and its ground verification tests. Specifically, system function and performance were validated through end-to-end testing with the ground support equipment, long-duration testing, thermal- vacuum testing, and initial-phase contingency tests, during which several issues were identified and subsequently corrected. VERTECS is scheduled to be launched aboard the H3 Launch Vehicle No. 6, with all preparations for launch and operations planned for completion by March 2025. This presentation reports the results of those activities.