Secondary spacecraft in 2016: Why some succeed (And too many do not)

This paper updates previous reviews of secondary spacecraft. With the number of new secondary spacecraft exceeding 100 per year, it is necessary to revisit the data, to better understand the trends and make new predictions. While CubeSats are the dominant type of secondary payloads, they are not the sole focus of this work. For 2016, we will re-examine our data and previous claims using a new set of classifications. We now believe that secondary-spacecraft developers are best divided into three groups: novices, traditionalists and experimentalists. Each of these groups approaches the development and operation of rideshares in very different ways, and the mission success rates between the three groups diverge. In this paper, we will review the census data (mass, lifetime, mission category, contributing organizations), examining trends and identifying deviations from (or confirmations of) previous predictions. Our focus will be on mission success and failure. We have accumulated sufficient information to define failure rates based on the type of organization, and to identify most-likely-causes based on the mission and organization type.