A system and method for identifying a safe path in a partially unknown environment in a time critical fashion includes identifying long range paths that avoid known obstacles. Short range paths within a receding horizon are identified corresponding to the long range paths, the short range paths avoiding known obstacles and unknown regions. Each short range path is broken into segments based on subsequent control operations or timing, and abort procedures are identified corresponding to each segment to enforce time critical availability of a safe action. Short range paths are excluded unless abort procedures can be identified for subsequent segments.