## 5 Structure
Following Bryce Tech's approach, the small satellites sensu large will mean the broad category of all classes of satellites up to 1200 kg, namely comprising femto (0.01-0.09 kg), pico (0.1-1 kg), nano (1.1-10 kg), micro (11-200 kg), mini (201-600 kg), and small satellites sensu stricto (601-1200 kg) [93] (p. 3). The transport platforms--from cars to ships to aircraft--have evolved in size with technological progress, which has also reached the satellites. Breakthroughs in microelectronics and low-cost, high-quality printed circuit board manufacturing and miniaturization have dramatically changed satellite sizes. The rise in small satellites results in the disruption of the tradition of large, expensive spacecraft [94]. The small satellites evolved from university experiments using commercial off-the-shelf (COTS) components dating back to the 1980s. However, before the mid-1990s, only 6% of small satellites launched were used for commercial applications. Since the 2010s, more than 60% of small satellites launched have been used for commercial purposes [95]. The cost-cutting transformation in orbital launching services, driven mostly by SpaceX, has supplemented and reinforced the miniaturization impact. Lowering launching costs opened doors to new business models and innovations [38; 55]. Small satellites offer advanced functions at a fraction of the mass and size (cf. Figure 8) of larger spacecraft, allowing cost-cutting. In particular, CubeSat technology was transforming space research and commercial ventures by expanding mission capabilities. CubeSats are built from 10 \(\times\) 10 \(\times\) 10 cm units weighing about 1.33 kg each. Their design includes a spacecraft bus/platform and payload/mission hardware [95]. CubeSats tackle tasks once reserved for larger satellites [97]. CubeSats have dominated the smallsats cohort since 2013, when they reached two-thirds of all satellites up to 600 kg and peaked in 2017 with 86% share in this category. This was nearly three-quarters of all small satellites sensu large [98; 99]. Figure 6: Number of active satellites since Sputnik up to 2023. Source: [91]. Since then, CubeSats' share has declined due to the rise in larger spacecraft (but still beholden to the smallsats sensu largo) used to form the mega-constellations of telecommunications satellites designed to provide global internet coverage. Previously, satellite internet was the domain of large corporations and governments operating at GEO. SpaceX, with its Starlink, disrupted this model by mass-producing low-cost satellites dedicated to LEO and launching them using its own rockets. Let us compare the data about the changing structure of mass classes of satellites (Table 1). One could notice the huge increase in the share of mini satellites (201-600 kg) in 2020 and 2022 compared to 2018. This was due to the mega-constellation rollout by SpaceX (Starlink, since 2019) and Eutelsat (OneWeb, since 2020). However, in 2023, the share of small satellites sensu stricto (601-1200 kg) was getting pretty close to that of mini ones. This is due to the new generation of Starlink spacecraft rollout, namely V2 mini (about 800 kg), since 2023 [100; 101; 102]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Mass Class**} & \multicolumn{4}{c}{**Share in Spacecraft Number**} \\ \cline{2-5}  & **2018** & **2020** & **2022** & **2023** \\ \hline Up to 200 kg & 63\% & 27\% & 25\% & 27\% \\ Mini (201–600 kg) & 7\% & 67\% & 71\% & 40\% \\ Small (601–1200 kg) & 15\% & 1\% & 1\% & 31\% \\ Rest (above 1200 kg) & 15\% & 5\% & 3\% & 2\% \\ \hline \hline \end{tabular} Note: mass classes based on [92] (p. 94). Source: own based on data from [93; 96; 98; 104].  
\end{table} 
Table 1: The changing structure of satellite mass classes over time. Figure 8: Decreasing mass and size of launching of satellites in the years 2011–2023 as measured by (**a**) mass and (**b**) number of spacecraft per launch. Source: own based on [6; 93; 96; 103]. Figure 7: Number of small satellites launched globally.