The Orion GN&C data-driven flight software architecture for automated sequencing and fault recovery

The Orion Crew Exploration Vehicle (CEV) is being designed to include capabilities that allow significantly more automation than either the Space Shuttle or the International Space Station (ISS). In particular, the vehicle flight software has requirements to accommodate increasingly automated missions throughout all phases of flight. This paper presents the Guidance, Navigation & Control (GN&C) flight software architecture designed to provide evolvable automation capability that sequences through software modes and configurations. This software architecture is required to maintain flexibility to address the maturation of operational concepts over time, permit ground and crew operators to gain trust in the system, and provide capabilities for human override of the automation in `off-nominal' situations. To allow for mission flexibility, reconfigurability and reduce the recertification expense over the life of the program, a data-driven approach is used to load the mission event plan as well as the flight software artifacts associated with the GN&C subsystem. The flight software schema for automated mission sequencing is presented with a concept of operations for interactions with ground and crew members. This data is managed through a prototype database of GN&C level sequencing data, which tracks mission specific parameters to aid in the scheduling of GN&C activities. A prototype architecture for fault detection, isolation and recovery interactions with the automation software is presented as part of the upcoming design maturation to respond with appropriate GN&C and vehicle-level actions in `off-nominal' scenarios.