The Boston University Student Satellite for Applications and Training (BUSAT) is a competitor in the University Nanosat Program (UNP) Nanosat-7 competition, a two-year event sponsored by the Air Force Research Laboratories (AFRL) and the Air Force Office of Scientific Research (AFOSR). The competition provides eleven university teams the guidance and support needed to develop a space flight mission and a functional satellite to support it. In this way, the UNP has not only sponsored an effective long-term engineering and scientific research project for hundreds of students, but has catalyzed interdisciplinary participation and widespread interest in scientific space flight at Boston University. BUSAT’s participation in the Nanosat-7 competition sets the stage for future educational space flight initiatives. In the long term, a successful demonstration of BUSAT’s novel design approach will aid future efforts to establish Boston University as a leader in space flight hardware development and education.
The BUSAT satellite is an attempt to provide a rapidly reconfigurable satellite bus that lowers overall mission cost by driving down interface costs. The bus is intended to provide launch opportunities for up to 24 experiments and provides all the necessary support for each of these “black box” missions to succeed, including power, data handling, downlink data telemetry, uplink command telemetry, diagnostics and much more. BUSAT developed from early design concepts that maximized modularity, or the ability to remove, re-orient, and replace a satellite component in a variety of locations around the satellite structure and with a variety of look directions . Additionally, optimization of both time-driven and money-driven processes during the entire lifecycle of the satellite was desired. The cubic mechanical structure clearly shows the influence of the CubeSat “containerized” form factor, as well as a robust mechanical design that emphasizes the need for extra safety measures when flying scientific experiments as secondary payloads.
Many satellite development programs follow a “one-of-a-kind” design path in which a unique satellite is developed specifically to support the needs of a distinct set of instrumentation. This method is both expensive and time-consuming . Because of the complexity and variability of satellite missions, a universal satellite bus has yet to develop fully, although at least one modular demonstration mission has received substantial support . BUSAT’s novel nanosatellite bus provides both the general utility of a multi-mission structure while at the same time retaining mission-specific adaptability to a wide range of instrument requirements. While BUSAT strives to optimize the design cycle by reducing recurring engineering costs, it is recognized that a truly universal satellite is inherently impractical on a university budget. This is supported by the fact that programs such as Space Plug-and-Play (SPA) have met with limited success operating under much more favorable budgetary constraints. However, while the concept of universality is unwieldy in its most general form, it can be effectively applied to a slightly narrowed subset of spacecraft missions, namely those requiring only basic system support functions.
The broad satellite bus functionalities required by this subset include rough pointing, low data rate telemetry and tolerance of duty cycling, and are achievable on a university budget.BUSAT’s target role in the spaceflight industry is therefore that of a mission broker for small scientific instrumentation. By adhering to standardized interfaces in a star network and arranged around a centralized bus, BUSAT facilitates mission sharing while at the same time driving down overall cost for payload developers and overall risk for launch providers.