A statistical survey of rideshares (and attack of the CubeSats, part deux)

In last year´s conference, we presented a statistical look at the 316 rideshare missions launched from 1990-2010, examining issues of mass, nations of origin and launch and mission type. Examinations of the data indicated that the broad range of mission types, sizes and participating nations could be classified in several useful ways. For example, we were able to forecast a bifurcation of rideshares into the CubeSat-scale and ESPA-scale categories. In this paper, we will expand on last year´s results in three meaningful ways. First, we will extend the analysis back to the first rideshare in 1960 and up through 2011. In doing so, we will be able to confirm what were anecdotal conjectures from the previous paper: that the changes in the numbers and demographics of rideshares can be tied to the availability of specific launch vehicles/systems (namely the Ariane, Dnepr, Shuttle and P-POD); and that the avalanche of CubeSat flights represents a significant change in the nature of rideshares. The second extension of previous work will be the further subclassification of rideshares into military, civil, commercial and educational categories. Identifying the nature of the rideshare operator will help us better correlate the launches available to different missions. For example, we will show that the large number of U.S. rideshare missions is actually a large number of DoD rideshare missions, with a handful of U.S. civil, commercial and educational flights (most of them in the last 5 years). With this new data, we will further refine our forecasts of the launches available for various mission categories in the next few years.