For the downlink elements of mission operations systems to be unprepared to identify anomalies or for the mission planning or sequence generation or commanding elements to fail to be prepared to respond to them is to ignore the realities of operating a mission. Thus, just as many anomalies which can be foreseen should have contingency responses prepared; those contingency responses which leave a system’s performance degraded should have alternate mission plans prepared as well. Preparation for anomalies begins by listing the most likely problems to occur as the mission proceeds. The only anomalies which need contingency plans are those which have a reasonable probability of occurrence, a significant compromise to success, and a necessary and useful reaction. For spacecraft anomalies which require uplink responses, four general levels of contingency preparedness exist. The lowest level, a plan which describes the response in text, may be sufficient for the less probable anomalies.