Secondary spacecraft in 2015: Analyzing success and failure

摘要

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. We review the census data (mass, lifetime, mission category, contributing organizations). examining trends and identifying deviations from (or confirmations of) previous predictions. For 2015, we introduce mission success metrics. We have assessed every secondary mission on a granulated scale of success, including milestones such as launch, ejection, first contact, commissioning and primary mission success. With this new data, several factors stand out: as expected, university-class missions have a much lower rates of mission success, with as high as 40% of missions failing to achieve all the primary objectives, compared to 20% of professional missions. However, there is good news: the very high failure rate can be explained by the fact that so many of these schools are flying their first-ever spacecraft; success rates increase significantly for follow-on missions. In this paper, we will address three questions: 1) Are there any lessons that new programs can glean from this high-level study of success and failure? (Answer: Yes! First, it is important to persist to that second launch. Second, certain types of missions and performance objectives lend themselves to increased success.) 2) Are there new trends emerging in terms of the organizations and missions participating in CubeSats? (Answer: NASA, the DoD and universities are all greatly increasing participation. And we think this will all change again in 2015.) 3) Is there a response/change in the rest of the secondary payload market? Are those missions continuing in the same numbers? Are there changes in the kinds of missions pursued among the "larger" secondaries? (Answer: we still don't know. The market is very fluid.).