Verification of a contract consisting of a lot of free text and no precise requirements is a complex task. This paper describes the approach taken at GSOC during the preparation of a geostationary communication satellite mission to make this task transparent and efficient for both the customer and the operations provider. For the management of contractual requirements the commercial software DOORS together with a few specific customizations was used. All requirements and activities related to their fulfillment were stored in a central database and linked with each other. For that reason complete traceability from contract to subsystem level tests, operational procedures, inspections and design documents could be ensured continuously. Manual generation of verification matrices was rendered unnecessary. An extraction tool made it possible to provide relevant information whenever requested to the customer who was not using DOORS. This approach also enabled verification of internal requirements and tracking of the execution status of the planned tests without additional effort. NomenclatureCDR = Critical Design Review DR = Detailed Requirement(s) ECSS = European Cooperation for Space Standardization PDR = Preliminary Design Review ORR = Operational Readiness Review SR = System Requirement(s) TAR = Technical Acceptance Review TR = Test Report TS = Test Specification TTP = Test and Training Plan

A major program at GSOC required the implementation of a requirements management tool. GSOC selected the software package DOORS for that purpose. The positive experience gained in this project, lead to the aim of establishing an in-house standard for requirements management and verification related topics. In order to achieve this goal a number of initiatives have been started:• An internal training program, designed for the special needs of an operations center, was set up to provide regular training sessions. The training is split between a basic DOORS user training and special sessions on specific topics for key personnel (e.g. project structuring)• A generic DOORS structure for an exemplary project was developed. This contains templates for all relevant documents and elements. The structure shall be used by all projects as basis for project-specific customization.• A GSOC standard set of templates was generated to create office documents from DOORS data by using Rational Publishing Engine (e.g. requirements specification, test specification, test report).• A basic set of DOORS extensions (DXL scripts) is provided to all users. The user gets a set of additional functions (e.g. enhanced import / export, configurable data analysis) without the necessity to develop own scripts.These initiatives increased the project managers' awareness about the benefit of using a standard requirements management approach. They also improved the acceptance of using DOORS among the project staff. Moreover, the initial effort for new projects to implement the requirements management process using DOORS is significantly reduced.

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Satellite data relay services for low-earth orbiting spacecraft are promising to change the operations world. Europe is building up a fleet of relay nodes. They rely strongly on optical communication. After more than a year of regular operations, sub-project EDRS-A can take a look back and tell about the challenges of this peculiar undertaking and the success that was achieved. It is also a story about the way to reduce operations effort through automation. I. About EDRSEDRS-A is the first commercial-grade laser communication relay satellite system. It is part of the European Data Relay System (EDRS) project, an undertaking of Airbus and ESA featuring end-to-end data rates of up to 1.8 GBit/s. The main purpose is to relay earth observation data from spacecraft in low earth orbit to ground stations in Europe in order to provide more earth observation data to the user in less time. Currently the system is used by the Sentinel 1A, 1B, 2A and 2B spacecraft. Fig. 1 The EDRS-A and EDRS-C nodes in orbit providing laser (red) and Ka-Band (green) connections (EDRS-A is on the left in this view).Two precursor missions were undertaken, where GSOC was already involved in operations. First, over 10 years ago the German radar satellite TerraSAR-X was launched with an early version of the laser communications terminal (LCT) on board. It was used for experimental purposes. In a campaign with the American NFIRE satellite it