Traditional satellite development programs involve extensive careful engineering analyses, modeling, testing, and mission assurance processes. Development programs can span many years; in some cases more than a decade can elapse between program initiation and first launch.  In contrast, agile space programs, and particularly CubeSats, reduce the development effort to levels that allow program durations measured in months rather than years. The key to the short development cycle of CubeSats is the CubeSat paradigm, which is distinct from the CubeSat standard.  The CubeSat standard is defined by the CubeSat Interface Control Document (ICD), which defines the interface between the CubeSat and the launch vehicle, and sets tight constraints on such factors as dimensions, mass, and hazardous materials. For the launch provider the ICD ensures that the CubeSat, as an auxiliary payload, will do no harm. The point of the CubeSat ICD was to ensure access to space at a cost where a mission failure was not intolerable. The original concept of CubeSats was as a teaching tool in a university environment; there was a high value placed on innovation and risk taking.  However, many non-university programs recognized the value of the CubeSat ICD for supporting a program of rapid technology development. The opportunity to fly a high-risk mission at nominal cost encouraged entrepreneurs to establish programs that required multiple generations of spacecraft design on a very short cycle, with the understanding that there will be failures on orbit.  However, these failures will all be lessons that lead to improved designs in the next generation of the satellite. The program is defined not by the capabilities of the first satellite to fly, but by the capabilities of the nth generation of satellite.  The CubeSat paradigm is the recognition that failures are a natural part of the development cycle, and that as much, or more, can be learned by having these failures in early flight models than through extensive ground modeling, development, testing, and mission-assurance programs. The CubeSat paradigm is a natural (although possibly not foreseen) outcome of the CubeSat ICD.