Reference Architecture for Space Production Systems
Creators: name:  D. SANDERSON 
name:   A. BROWN 
name:   J. LEADBETTER 
name:   A. GORDON 
name:   E. SHIRES 
name:   S. RATCHEV 
Publisher: name: Proceedings of  the 9th European Conference for Aerospace Sciences. Lille, France, 27 June - 1 July, 2022
Year: 2022
Subjects: SPACE EXPLORATION
ISRU

description: A desire for production to occur in space has a long history, whether this is the historically manual assembly and repair of space assets or the planned autonomous additive manufacture of human habitats on other planets. Organisations such as NASA have devoted a large amount of resources to developing the technologies for in-space production. An example of this is the NASA\'s Space Technology and Exploration Directorate strategy on In-Space Assembly, Construction, and Operations based out of the Langley Research Centre: it focusses on ``On-orbit autonomous assembly and aggregation of large space structures, modular designs, and interfaces to meet the Agency\'s science and exploration future mission needs\'\'. There is a large body of work on the technologies to enable in-space production, often through the use of autonomy and robotics. Other work considers how existing technology can be used to enable that capability, or how the software for such a capability could be designed and verified. Similarly to the integration of in-situ resource utilisation (ISRU) technologies, any use of in-space production technologies will require deep integration with existing space architectures. Although some work is evident in the literature on how this might be accomplished for ISRU, particularly in Lunar or Martian mission scenarios, there is little in terms of the detailed integration with software systems, or how this might be accomplished for platforms dedicated to autonomous production operations. In this paper, we therefore propose a conceptual framework and reference architecture for space production systems (SPS). A review of the existing digital architecture approaches and standards for space systems identifies a number of avenues, including the NASA core Flight System (cFS), ESA\'s Space Avionics Open Interface Architecture (SAVOIR) advisory group, and the Consultative Committee for Space Data Systems (CCSDS) Reference Architecture for Space Data Systems (RASDS). Both the cFS and SAVOIR approaches define a component-based software system integrated over a databus. CCSDS also defines a similar architectural approach --- through a service-oriented architecture, which is a higher-level paradigm that often utilises component-based software design --- but abstracts away from the specific integration approach required. The intention for all is to use functional separation and software engineering principles to enable software standardisation, reuse, compatibility, and flexibility of the overall system. While the CCSDS RASDS is only concerned with components of a data system, it is acknowledged in the standard that ``a full space system design would include other classes of components and connectors not addressed\'\'. We therefore extend the CCSDS suite of standards to meet the requirements of an SPS. Our reference architecture for space production systems (RASPS) is defined through the functional, information, connectivity, and communications viewpoints. An initial design and integration is presented with reference to a number of common key use case requirements for advanced production systems. This design is then validated through implementation in a self-contained ground-based robotic demonstration cell that can perform a flexible assembly task. The demonstrator cell has been successfully used to assemble a variety of hexagonal panels in a number of different designs, where each panel had varying integrated technologies.