Measuring Complexity and Risk of New Small Satellite Endeavors

Abstract

The space industry has greatly increased the use of small satellites to conduct civilian and commercial space missions. As recently as ten years ago, small satellites were not applicable to operational endeavors consisting primarily of simple unstabilized, battery-powered, single frequency store-and-forward spacecraft used for technology demonstrations. The irony is that small spacecraft designers, in their quest to reduce costs through streamlined development and use of “off-the-shelf” technology have in many cases pioneered the use of advanced devices in space. The functionality achievable in small packages has taken a leap forward due largely to the availability of increased space-compatible computational power and memory. While it is clear that the current spectrum of small-satellites offers a rich suite of capabilities, it is debatable whether the associated complexity of building these systems has outstripped the budget and time that industry and its sponsors are willing, or able, to commit. Recent failed or impaired small satellite missions have amplified concerns about the applicability of small satellites to operational and commercial applications. Experience shows time and again that risks often do not manifest themselves ahead of time or in obvious ways. However, when examined after the fact, loss or impaired performance is often found to be the result of mismanagement or miscommunication in deadly combination with a series of “low probability” events. Such occurrences, often when the program is operating near the budget ceiling and/or under tremendous schedule pressure, result in failures due to a lack of sufficient resources to test, simulate or review work and processes in a thorough manner. While small satellites arguably result in lower absolute costs and shorter development times, these benefits may have been achieved at the expense of increasing performance risk. One key question to be answered is when does a mission become resource constrained such that it is prone to failure? This paper takes an objective look at small satellites using a complexity index to normalize development time and costs. An examination of the failure rates of small-satellite missions and conclusions regarding dependence on system complexity are presented. Finally, an example of the methodology to a future small-satellite endeavor is presented with a commentary on the applicability of the approach to risk planning.