Verification Approaches for Nano- and Micro-Satellites

There is growing interest for the development of light, small, high-performance spacecraft (S/C) platforms for a wide range of missions. In the early stages of the small-satellite era, both nano-satellites (<10 kg) and micro-satellites (>10 kg) were mainly intended for educational and technology demonstration goals [1]. Nowadays, they are a consolidate means for Earth observation, where they dramatically reduce mission costs. We are now at a turning point, where nano- and micro-satellite systems can accomplish interplanetary missions beyond the boundaries of low Earth orbit (LEO) [2,3]. However, in spite of the substantial increase in low-mass satellites launched since 2013, several statistics show the low success rate of these commercial off-the-shelf (COTS)-based cost-driven systems. Only half of nano-satellites succeeded in mission operations after a successful launch in the last 15 years [4]. The low success rate of nano-satellites is acceptable, up to a certain extent for educational or technology demonstration missions. This may stem from the way in which university-led projects design and carry out the S/C ground verification process, which lacks repeatability and rigor routinely found in industry. However, even though a nano-satellite is relatively inexpensive, if the S/C is launched for commercial or scientific exploration purposes, failure is not really an option. We should thus ask ourselves what technical challenges and programmatic difficulties must be faced in order to substantially increase the reliability of nano- and micro-satellite missions. The historical causes of low-mass satellite failure can be traced back to (a) lack of system-level testing due to schedule and budget constraints, (b) inadequate thermal design and verification, and (c) use of COTS electronics. Clearly, rigorous ground verification approaches—tailoring the existing testing standards for traditional large-/medium-class satellites—are needed to effectively face such challenges. It is therefore our pleasure to introduce this Aerospace MDPI Special Issue on Verification Approaches for Nano- and Micro-Satellites, which aims at addressing, at least in part, the above concerns.