Truly Modular and Open System Design is Difficult

In the United States, major defense acquisition programs must implement a modular open systems approach (MOSA) as required by U.S. law. (Defense Standardization Program, 2016). Some in the defense community have focused on MOSA as a checklist compliance activity. However, designing economically and operationally competitive system platforms that are truly modular is extremely challenging. Many such modular system platform efforts fail to meet early expectations for convenience, cost, and community uptake. Open standards are challenging as well. If a highly successful, stable, well-documented, appropriate open standard is available for an interface, then leveraging such a standard can be fairly straightforward. However, often there is no obvious or adequate open standard available and the system platform owners have to organize a community to bring such a standard into existence.

This paper will review three concrete examples of such MOSA efforts. The three cases cover both commercial and defense applications as well as covering both hardware and software. The two systems that focused on hardware modularity did eventually go into production but did not completely fulfill early expectations for their programs. The software system used an out-of-the-box approach and achieved a best-in-class result in terms of economic effectiveness, time to market, and stakeholder satisfaction. This paper will discuss underlying challenges that seem to be common to all such efforts, review the results of the three cases, and offer some simple guidelines for increasing the probability of success for such a program.