ESTRACK, the European network of tracking ground stations, is remotely operated by a 24 h team located in ESOC, Darmstadt, Germany, called ECC team. In order to provide the requested tracking services the ECC team has to coordinate with several entities: the Scheduling Office, the satellite mission teams, the local maintenance teams and the external tracking service suppliers. The growing interest on human factors impacting space missions triggered the collection of related measures using ESTRACK service availability as initial case study. Since 2007 the ESTRACK incidents attributed to human errors of the ECC team and the interacting entities have been isolated for a dedicated analysis and investigation. After an initial cleaning of the records, the paper describes the operational context of this collection of documented human errors and compares them against the volume of performed activities. A second classification discriminates between nominal and contingency operational scenario. The result is an uneven distribution of human error rate, mostly toward the execution of nominal procedures. The core of the analysis consists of the driver identification for each human error. The drivers are grouped in two categories: endogenous and exogenous drivers ["Human Error: Cause, Prediction, Reduction", Senders and Moray, 1991]. The endogenous drivers are connected to the individual responsibility of the ground operator with respect to his/her responsibility and acquired knowledge. The exogenous drivers are related to external factors inducing the operator in error. Out of this distribution the three most accounted drivers (not following procedures, lack of attention, inadequate MMI) are discussed with examples and recovery goal. This analysis provides the basis for corrective and preventive measures to prevent human errors in ESTRACK services, although the system and organisation evolution will present other new challenges to the operators. It will also constitute the methodological reference to analyse human errors of spacecraft operators.
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