Technical Overview and Comparative Assessment of the AkSat U2 and ViskanSat Sub-Orbital Picosatellite Demonstrators for Flight Aboard the Rhumi-1 Sounding Rocket

Abstract

This paper presents a comprehensive engineering overview and comparative analysis of two sub-orbital picosatellite demonstrators AkSat U2 and ViskanSat developed as compact, low-cost platforms for validating avionics, structural integrity, environmental sensors, and autonomous data-logging systems in near-space conditions. Both satellites share an identical system architecture, power subsystem, electrical interface, and mechanical form factor (50 mm × 50 mm, <100 g), allowing standardized payload integration and side-by-side performance comparison. Each unit integrates a 3D-printed structural enclosure, an ESP32-based microcontroller unit, an MS5611 high-resolution barometric altimeter, and an MPU6050 6-axis inertial measurement unit, enabling pressure-altitude profiling, inertial dynamics measurement, thermal logging, and low-power duty-cycled data acquisition. The satellites are intended for an upcoming flight aboard the Rhumi-1 sub-orbital sounding rocket; a micro-payload launch vehicle designed to reach altitudes of approximately 30–75 km. This trajectory provides an ideal environment for validating barometric sensors, inertial systems, structural resilience, and power subsystem endurance under rapidly changing atmospheric and dynamic conditions. The paper details the engineering design, subsystem implementation, software architecture, telemetry workflow, and low-power operational strategies of both satellites. A direct comparison highlights subsystem reliability, manufacturing reproducibility, and opportunities for scaling design principles toward future balloon-borne, aerial-platform, or orbital femtosatellite missions. The work demonstrates that low-cost picosatellite demonstrators, developed using additive manufacturing and commercial off-the-shelf components, serve as effective technology-readiness enhancers for academic and research-driven near-space missions