The software strategy for SPA Plug and play spacecraft

The space market could benefit immensely from satellites that not only start their service lives as soon as possible, but can perform their on-orbit roles with minimal intervention from ground operations. The development of flight software techniques that addresses both of these issues has been ongoing at the Air Force Research Laboratories (AFRL) Responsive Space Testbed (RST) for a number of years. The Space Plug&play Avionics (SPA) standards define the means by which software (and hardware) components installed on a networked spacecraft bus deliver their data interfaces and self-organize into a coherent, functional system. A collection of modular, pre-validated software applications are maintained in a ¿virtual store room¿ and are called upon to configure tailored mission capabilities based upon operational needs. Mission ¿Activity Agents¿ encapsulate the logic and sequences necessary to accomplish satellite operations autonomously. Their execution is coordinated using on-orbit planning resources and a priority-based scheduler. The PnPSat mission was the first formal application of these techniques. In the course of the program a spectrum of software tools were authored to support the rapid design, prototyping, and testing of flight software modules for SPA-based satellites. The AFRL Operationally Responsive Space (ORS) assembly depot is being populated with an assortment of hardware and software components sufficient to build a reasonably diverse array of tactical small satellites. The tools being used, and the philosophies employed in their application, are ready for exposure to the larger space community.