You say “Picosat”, I say “'CubeSat”: Developing a better taxonomy for secondary spacecraft

Abstract

Secondary spacecraft are being put in orbit at the rate of hundreds per year, with each year smashing the record set by the previous. These “piggyback” missions (which reach orbit using the unused mass/volume in a launch vehicle) come from every source: universities, government labs, large contractors, startups and even art collectives (?!?!). There are Beepsats, journal-worthy science missions, operational sigint missions, radio Amateur missions, technology demonstrations and venture-capital-backed remote sensing missions. For today, secondary spacecraft are almost exclusively low-Earth-orbiting missions, though even that limitation is changing. Despite the breadth of mission sponsors, mission developers, mission types and orbital domains, our terminology is unchanged and contradictory: cubesat (or CubeSat), picosat, smallsat. More importantly, decisionmakers hear a phrase like “half of all CubeSats fail” and assume that there's something inherently flawed in the CubeSat concept - instead of recognizing that half of “all” CubeSats fail because hobbyists make up more than half of all CubeSats, and their ad hoc practices fail two-thirds of the time. In this paper, we propose two taxonomies for secondary spacecraft: the first, based on the type of mission developer (e.g., Hobbyist, Crafter, Industrialist) and the second based on the type of mission flown (e.g., constellation, experiment, short operational, long operational and extreme operational). We will contrast these taxonomies against the existing ones (such as NASA's Class A/B/C/etc). Finally, we will use these new taxonomies to parse our existing secondary spacecraft database to provide meaningful examinations of mission types, mission success rates and opportunities for further study.