Demonstrating the accessibility of Space with SBUDNIC

SBUDNIC is a student-managed project that demonstrated the potential for efficient, inexpensive, open-source satellite design and production by (1) launching a 3U CubeSat with a reproducible parts cost of 6.210 USD; (2) completing design, development, and testing within 14 months; and (3) doing this in a team of under 30 undergraduate and graduate students with no prior Space systems experience. SBUDNIC’s low unit cost precluded the use of most Space-qualified components, leading to novel subsystem designs that deviated from industry practices. A particularly important contribution to Space technology was a Kapton drag sail designed to stabilize SBUDNIC and accelerate its deorbiting. Over SBUDNIC's lifetime, the team used publicly available positioning data (collected by the United States Space Force, and as compiled and shared on space-track.org) to monitor the trajectory of SBUDNIC and the other 3U satellites that launched with it. SBUDNIC's reentry from 550 km was swift, especially in comparison to the 3U reference satellites: it occurred on August 10, 2023, after only 441 days in Space. By comparison, the orbit of the 3U reference satellites decayed around 50 kilometers over that same time span. SBUDNIC's rapid decay therefore suggests that the drag sail was effective and functioned to purpose. SBUDNIC’s deorbit was 95% faster than anticipated by pre-launch engineering simulations, suggesting a far-higher-than-average atmospheric density at its altitude, likely influenced by heightened solar activity, although further investigation might identify additional contributing factors to such accelerated descent. SBUDNIC's key goal of making Space exploration more accessible is not limited to the availability of the parts used. The entire satellite project follows the Open Architecture philosophy, and significant effort was made to engage student and hobbyist communities with the mission. The timely program execution, launch, and subsequent deorbit of SBUDNIC demonstrated techniques for manufacture and design that can facilitate low-cost, short-timeline satellite programs for many applications. Additionally, SBUDNIC's orbital decay data sets, though unintended, offer scientific value for Space Weather studies, underscoring the potential of LEO satellites in understanding geospace dynamics. The SBUDNIC project was a collaboration between the National Research Council of Italy and the Brown University School of Engineering, with support from D-Orbit, AMSAT-Italy, La Sapienza-University of Rome and NASA Rhode Island Space Grant.