Design of the Structure of an Earth Observation 3U CubeSat for Hyperspectral Imaging

Abstract

Hyperspectral imaging has a variety of commercially important applications in Earth observation because of its advanced functionalities that enable precise material identification. This manuscript presents the structural design and analysis of a 3U CubeSat carrying a hyperspectral imaging payload, as part of the Earth Moon Education CubeSats (EMEC) mission by EuroMoonMars. Due to its high resource demands, hyperspectral imaging requires an efficient design of the structural subsystem to accommodate the payload and other subsystem components, but publicly available research on this is extremely limited. A CAD model of the complete CubeSat was designed in Autodesk Fusion based on the mass, protrusion, and CG requirements from the dispenser. The design satisfied these requirements, and the total mass of the CubeSat was 6.482 kg after accounting for margins. Structural FE analyses were performed using ANSYS Mechanical to ensure that the CubeSat withstands the vibrational loads (quasi-static loads, random vibrations, and shock loads) from the launch vehicle. After simplifying the geometry of the CAD model to reduce the computational effort, and applying appropriate loads and constraints, the analyses were run on a multi-core processor. The first natural frequency of the CubeSat was 822.69 Hz, which was above the minimum requirement of 115 Hz, indicating that resonance was unlikely. The margins of safety against yielding for the quasi-static loads, random vibrations, and shock loads were 9.95, 3.09, and 0.13, respectively. Based on these preliminary results that showed positive margins of safety, it was concluded that the CubeSat withstands these loads. A sensitivity analysis on uncertain parameters was conducted in optiSLang, and the results of this will be used for validating and updating the FE analyses, to be carried out by testing a physical model of the CubeSat in dedicated setups.