KAAVACA -- Why SmallSats Fail and How To Stop Them

SmallSats, defined as satellites under 180 kg, have shown a persistent failure rate of approximately 40% from 2000 to 2019, with no discernible improvement over time. Nearly all of these Beyond-Day-One (BDO) mission failures can be attributed to unexplained issues within satellite electrical systems. This research proposes that nearly all such failures can be traced to thermal cycling-induced degradation of trace wire within printed circuit boards (PCBs). SmallSats, which lack active thermal control systems, experience orbital thermal cycling as they alternate between solar exposure and eclipse, often undergoing ±25°C swings each 90-minute orbit. These thermal variations induce mechanical stresses due to differential expansion and contraction with change in temperature, accelerating material fatigue and defect propagation. In the first part of this paper, a fracture mechanics-based approach is used to simulate how manufacturing imperfections in SmallSat PCB traces propagate under orbital thermal cycling. Results indicate that orbital cycling alone cannot account for the observed rates of electrical failure, predicting significantly longer lifespans than flight data suggests. The discrepancy is resolved by considering electrothermal cycling: local heating and cooling caused by intermittent usage/spiking of electrical systems. Though it may seem as though this effect is negligible, it is intensified at deformation sites where orbital cycling has already stretched and thinned out the trace wire. and when orbital and electrothermal cycling are modeled concurrently, predicted failure rates align closely with empirical mission data. The second part of this paper presents a mitigation strategy: Kaavaca, the (K)corrugated Authority Against Volatile Astronomical Conditions at Altitude—a systems engineering approach to prevent the aforementioned thermal cycling induced failure mode while adhering to the specific needs of SmallSat programs. Named after the Sanskrit word for "armour," Kaavaca protects the satellite by thermally isolating the solar array (the primary heat source) from the bus, as well as integrating radiators in both subsystems such as to decouple the thermal cycling between the two. In the middle, a pseudo-actively managed “thermal battery” stores excess heat from the solar array. This stored heat can be redistributed among the satellite as it passes through the Earth’s shadow, using conductive louvering to control the heat transfer to/from each subsystem. Effectively, Kaavaca operates as a thermal cycling absorber, offsetting thermal cycling loads from sensitive, critical electronic components to the thermostructurally resistant thermal battery. Furthermore, the system is parameterized and mission-adaptable, such as to suit the typical range of mission profiles for SmallSats; while also meeting common SmallSat requirements, with no deployables and sufficient solar coverage to recover from an uncontrolled tumble. All in all, Kaavaca has the potential to promote a promising path toward reducing the dominant failure modes in SmallSats. With further development, it could significantly enhance mission reliability and help democratize access to space-based research.