STPSat-1: A New Approach to DoD Experiment Spaceflight

For small satellites, finding affordable access to space is a daunting hurdle. The Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA) promises to make excess capacity on future EELV launches available for the Department of Defense (DoD) Space Test Program (STP) and other organizations as a lower-cost launch alternative. STP Satellite Mission 1 (STPSat-1) is the first STP satellite built specifically to exploit this capacity. STPSat-1 continues STP’s mission to provide access to space for DoD sponsored experiments. This spacecraft hosts four such experiments: Spatial Heterodyne Imager for Mesospheric Radicals (SHIMMER); Computerized Ionospheric Tomography Receiver in Space (CITRIS); Micro-Electro-Mechanical System (MEMS)-based PicoSat Inspector (MEPSI), and; Wafer Scale Signal Processing (WSSP). Consistent with STP’s mission, these experiments will demonstrate new technologies for space applications. This paper discusses several technical challenges being overcome by the STPSat-1 team. SHIMMER is the primary driver for spacecraft attitude and thermal performance. ESPA restrictions tightly constrain volume and mass. Limited knowledge of the launch environment exists since Delta IV has not yet flown (at this writing). This paper will discuss the approach used to meet these technical challenges, present organizational structures used to optimize communications, and address design-to-cost and mission risk constraints