Analysen zur Dynamik von Kugelhaufen-Hochtemperaturreaktoren

With the aid of the -axial-one dimensional diffusion program DYNOTTO in this work the dynamical accident behaviour of pebble bed high temperature reactors is investigated. The effects of temporal xenon concentration changes, temperaturedependent variations of the radial neutron losses and the possible accident 'water ingress' have been included in the program. An analytical simulation of the experiments performed at the AVR in Julien come to a good, agreement between themeasured results and the arithmetical results. Also the accident behaviour of other HTR-concepts is described analytically The results confirm, also for extremely impossible accident situations, that pebble bed high temperature reactors show a high inherent safety, which especially is effective for small HTRs

EnMAP Ground Segment: Design and Status of the Integration and Technical Verification and Validation Phase

EnMAP (Environmental Mapping and Analysis Program) is a German hyperspectral satellite mission, where the ground segment is operated by the Earth Observation Center (EOC), and the German Space Operation Center (GSOC) of the German Aerospace Center (DLR). The ground segment comprises all the facilities and systems required on Earth to control and operate the mission. It specifically facilitates access for the user segment to the space segment, including the commanding of the satellite, ordering and receiving data, and finally the processing, archiving and distribution of data. The Ground Segment consists of three sub-segments (the Mission Operations Segment, the Payload Ground Segment and the Processor and CalVal Segment), further decomposed into fifteen subsystems. By the time of the presentation it has just finished its Production Phase, where the subsystems were procured, clearly stating their readiness for integration into the Ground Segment by their Technical Verification and Validation. These subsystems are now integrated and their common functioning verified. Two main topics are identified as follows: on the one hand the status of the Ground Segment's subsystems is presented. On the other hand the focus of the presentation lies in the design of the ITVV Phase. During this phase the ground segment and its subsystems have to prove their capability for ordering, commanding, receiving, processing, archiving and distributing the mission's data according to the requirements imposed on it. This is performed in different stages. The presentation starts with an overview of the development model of the ground segment. This comprises its contributing fifteen subsystems and their interfaces as well as use cases accounting for the dynamic nature of the ground segment. Further the organisation of the requirements is shown, which are validated during the ITVV phase. Based on that knowledge the different stages of the ITVV Phase are presented, starting out with the subsystem verification on different levels. This is followed by the sketch of the verification of the interfaces and the ground segment's verification based on scenarios

On the Design of the Ground Segment for the Future Hyperspectral Satellite Mission EnMAP

The ground segment of the future German hyperspectral satellite mission EnMAP (Environmental Mapping and Analysis Program; www.enmap.org) is developed by the Applied Remote Sensing Cluster and the German Space Operations Center at the German Aerospace Center (DLR). The launch is planned for 2013. This paper describes the EnMAP mission - being currently in its detailed design phase - and focuses at first on the analysis of the development approach for the ground segment formed by 15 subsystems. At second the ground segment and subsystems designs themselves with their relations to the space and user segments are detailed

Status Report of the EnMAP Ground Segment: Presentation of the Design and the Changes Recently Accomplished

EnMAP (Environmental Mapping and Analysis Program, www.enmap.org) is a German, Earth observing, imaging spectroscopy, spaceborne mssion planned for launch in 2020. This work reflects the current status of the EnMAP Ground Segment, currently procuring its facilities and elements for later testing and integrating them. The Ground Segment’s Design Model is discussed as well as its constituents are introduced. It further discusses the recent changes to be respected by the design covering the topics, how low-quality data is handled within the Ground Segment, how the files aboard the satellite are deleted to ensure a maximum data security, and how the moon could serve as further calibration source during the EnMAP mission