A risk-aware architecture for resilient spacecraft operations

Abstract

Abstract-In this paper we discuss a resilient, risk-aware software architecture for onboard, real-time autonomous operations that is intended to robustly handle uncertainty in spacecraft behavior within hazardous and unconstrained environments, without unnecessarily increasing complexity. This architecture, the Resilient Spacecraft Executive (RSE), serves three main functions: (1) adapting to component failures to allow graceful degradation, (2) accommodating environments, science observations, and spacecraft capabilities that are not fully known in advance, and (3) making risk-aware decisions without waiting for slow ground-based reactions. This RSE is made up of four main parts: deliberative, habitual, and reflexive layers, and a state estimator that interfaces with all three. We use a risk-aware goal-directed executive within the deliberative layer to perform risk-informed planning, to satisfy the mission goals (specified by mission control) within the specified priorities and constraints. Other state-of-the-art algorithms to be integrated into the RSE include correct-by-construction control synthesis and model-based estimation and diagnosis. We demonstrate the feasibility of the architecture in a simple implementation of the RSE for a simulated Mars rover scenario.

Towards Architecture-wide Analysis, Verification, and Validation for Total System Stability During Goal-Seeking Space Robotics Operations

“…We have discussed in prior work 1 some examples of (limited) resilient behavior on spacecraft, such as the Remote Agent Experiment flown on Deep Space One, 2,3 the autonomous navigation capability on Deep Impact, 4,5 and the Cassini spacecraft's onboard orbit insertion calculations. 6 We have also discussed layered autonomy architectures, like Remote Agent, CLARAty 7,8 and the Autonomous Sciencecraft capability on Earth Observing One.…”

“…6 We have also discussed layered autonomy architectures, like Remote Agent, CLARAty 7,8 and the Autonomous Sciencecraft capability on Earth Observing One. 9 To restate, the key distinctions and innovations in the RSE framework (shown in Figure 1) include, as originally given in: 1 (i) The development and use of formal architectural analysis to perform tradeoffs and inform the appropriate allocation of capabilities to the deliberative, habitual and reflexive layers. This will result in systems with flexibility to adapt to their uncertain environments and potential mission changes.…”