D5.2 Analysis of existing orchestration mechanisms... 3 Executive Summary This deliverable is the output of task 5.2 Understanding the challenges for distributed computational analysis across Europe. The task activities started defining a set of aspects for which the project would like to investigate their status in existing workflow and orchestrator systems. These aspects relate to the distribution of data and computation, to the support to sensitive data, and to the support for data provenance and reproducibility. In addition to questions related to these topics, other generic questions were put all together. An initial classification of workflow environments and orchestrators was also done, and from there the task searched for information about the different systems. The information was provided in some cases by project partners, in other cases by system owners and in other cases fetched by partners from websites or other sources of information. From this initial catalogue, the partners involved in this activity selected the most promising ones that were invited to present in two workshops. The workshops were online and organized quite informally, but enabled a lot of discussion and provided in-depth information on the topics more relevant to the project. The information collected in the two phases of the task (catalogue elaboration and workshops) is summarized and analysed in this deliverable.