Autonomous spacecraft rendezvous is an enabling technology for many future space missions, but anomalies in recent flight experiments suggest that safety considerations will play a critical role in mission success. This paper presents a method for online generation of safe, fuel-optimized rendezvous trajectories that guarantee passive collision avoidance for a large class of anomalous system behaviors. We examine the cost of imposing safety as a problem constraint and of additional constraints that guarantee infinite horizon passive collision avoidance while enabling future docking retries. A convex collision avoidance formulation was introduced and determined to provide computationally fast solutions at a small fuel expense. Several examples using both rotating and non-rotating targets are presented to demonstrate the overall benefits of incorporating these safety constraints when compared to nominal trajectory design techniques.

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Formation flying is a key technology for many planned space missions that will use multiple spacecraft to perform distributed observations. This paper extends p r o vious work on the design of a highly distributed formation flying control system that uses linear programming to determine minimum fuel trajectories for the spacecraft to remain within some specified tolerance of their "desired points". The primary contribution of this paper is that it presents a direct procedure for calculating the fleet reference point (called the virtual center) that can be used to determine the desired states for each vehicle in the fleet. The calculation of this virtual center is based on measurements available from the relative navigation sensing system (carrier-phase differential GPS) developed for this application. The selection of the reference point includes a weighting on fuel use across the fleet, which facilitates increased coordination and cooperation within the decentralized control system. Full nonlinear simulations are presented to demonstrate the reduction in fuel use that can be obtained with this improved cooperation.

Autonomous spacecraft rendezvous is an enabling technology for many future space missions, but anomalies in recent flight experiments suggest that safety considerations will play a critical role in mission success. This paper presents a method for online generation of safe, fuel-optimized rendezvous trajectories that guarantee passive collision avoidance for a large class of anomalous system behaviors. We examine the cost of imposing safety as a problem constraint and of additional constraints that guarantee infinite horizon passive collision avoidance while enabling future docking retries. A convex collision avoidance formulation was introduced and determined to provide computationally fast solutions at a small fuel expense. Several examples using both rotating and non-rotating targets are presented to demonstrate the overall benefits of incorporating these safety constraints when compared to nominal trajectory design techniques.