Sabrina Eberle

EnMAP Ground Segment Design: An Overview and Its Hyperspectral Image Processing Chain

EnMAP (Environmental Mapping and Analysis Program; www.enmap.org) is the first German hyperspectral remote sensing satellite mission. This chapter focuses on the challenges on the design of the ground segment as a whole and in particular of its image processing chain. In the context of the system response time we investigate the ability of tilting the satellite which allows for frequent revisits and enables meaningful downstream change detection activities on a global scale. In the context of comparable and high-quality controlled products we investigate in detail the processing steps to radiometrically calibrate, spectrally characterize, geometrically and atmospherically correct the data. The status corresponds to the baseline for the production activities of the ground segment, namely only minor changes are expected. The launch is planned for 2016. The establishment and operation of the ground segment is under responsibility of the Earth Observation Center (EOC) and the German Space Operations Center (GSOC) at the German Aerospace Center (DLR).

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 first on the analysis of the development approach for the ground segment formed by 15 subsystems. Second the ground segment and subsystems designs themselves with their relations to the space and user segments are detailed.

Towards a critical design of an operational ground segment for an Earth observation mission

Abstract The ground segment for the future remote sensing mission Environmental Mapping and Analysis Program (EnMAP; www.enmap.org) is developed by the Earth Observation Center and the German Space Operations Center at the German Aerospace Center. The launch is scheduled for 2017. An operational satellite ground segment is a highly complex heterogeneous system which has to cope with different levels of criticality, novelty, specificity, and to be operated for many years. It consists of equipment, hard- and software as well as operators with their procedures. The strengths of the global coherence of the segment-wide approach bringing these aspects together is examined and not on the local details of segment-specific issues. However, the effects on two software-based elements of the ground segment are considered in more detail, namely the product library and the level 2geo processor. The development methodology and how the critical design of the complete ground segment finished its detailed design phase successfully was achieved is analyzed. As a measure of the maturity of the design, its stability across the project phases is proposed.

The user interface of the EnMAP satellite mission

The Ground Segment for the future hyperspectral satellite mission EnMAP (Environmental Mapping and Analysis Program) will be designed, implemented and operated by the German Aerospace Center (DLR). The Applied Remote Sensing Cluster (DFD) at DLR is responsible for the establishment of a user interface. This paper provides first issues on design and functionality of the user interface. The user interface consists of two online portals. The EnMAP portal is the central entry point for all users interested to learn about the EnMAP mission, its objectives, status, and results. The EnMAP Data Access Portal (EDAP) provides a set of functions for registered users that will support the international EnMAP user community. The operational services offered through the EnMAP portal will be complemented by a service team, EnMAP Application Support, offering expert advice on the exploitation of EnMAP data.

Technical and operational investigations of the real-time communication for robotic missions

Robotic missions become more and more interesting for many applications in space. Especially there where human space flight is too expensive or not applicable, one is tempted to use robotic missions to reach the target. Whereas operations of such missions are maybe not as complex as human ones (no life support environment needed), they are still very challenging, especially for teams which until now worked mainly with non-robotic satellites. When talking about robotic mission operations, one needs to discuss in general some typical scenarios. This could include debris removal, refueling or in general on orbit servicing activities. Even all of them use in such or another way robotic fixtures, operational fingerprint may be different. Whereas one type of the mission needs short but intensive activity of the operations team, another one can be stretched in even years with short periods of activities only. The paper gives an overview of such missions and specific operational aspects. The GSOC prepares its infrastructure and operations for the upcoming and potential robotic missions. These preparations include wide spectrum of technical and operational investigations, as such missions impose many new requirements. One of areas which are especially important for the robotic mission operations is the communication chain. Aiming for the real-time telepresence, including haptic feedback and stereoscopic imaging, makes the communications essential for the mission. For the operator on the ground it is very important to have a feeling of immersion to perform all tasks. Not only the technical arrangement, but maybe even more importantly the operational environment, needs to fit to the requirements. Analyzed operational impacts include mission safety, operational procedures, priority regulations and training of the personnel. The analysis which we performed shows how challenging such setup could be. The results of the analysis are presented, together with a discussion on side aspects of such solutions and their influence on satellite operations. Further analysis directions are proposed. As a technical verification, we performed intensive investigations on a packet delay in IP networks. The measurement setup and overview of the results is shown as well. Also the analysis of usage of different off-the-shelf components (basebands, edge router) has been performed and the operational impact has been assessed. The tradeoffs between different software and hardware solutions are shown as well. Finally we spend some place on a proposal for a future mission operations concept with real-time communications.

Ground Segment Design for On-Orbit Servicing Missions at GSOC

The interest in On-Orbit Servicing (OOS) space missions is growing. Such missions pose challenging requirements to ground segment design for these mission types. Especially when robotic elements, like rovers or robotic manipulators, come into play, legacy and proven ground segment concepts need revision and mission type-specific upgrade. Driven by the strategy to enable support of such missions in near-Earth space, the German Space Operation Center (GSOC) undertakes significant effort to achieve the desired readiness on technical and operational levels. This publication gives an overview about current activities at GSOC from a system engineering point of view and describes current mission preparation activities and future design tasks. The presented technological developments are of generic nature; however, a two-satellite, low-Earth orbit (LEO) mission with a robotic manipulator, which dominantly drives communication requirements, is taken as example to illustrate the presented concepts. That mission type is a very likely candidate for near-term OOS missions because of two reasons: First, the growing number of space debris poses a non-negligible threat to space operations, with large inoperable satellites in polar orbits of heights between 700 and 900 kilometers being the most vulnerable ones. Second, the life-time extension of valuable space assets may be a cost-saving alternative to the replacement by a new satellite. Active space debris removal and OOS almost inevitably require robotic in-space elements. If tele-operated in LEO regime, robotic mission operations can even take place under telepresence conditions, i.e., with visual and haptic feedback. For robotic tele-presence to function, a near-realtime communication environment with low latency and low jitter is therefore required. GSOC currently specifies the required equipment for innovative telecommand and telemetry communication chains and a generic ground segment design that supports Launch and Early Operations Phase and routine operation phases of OOS missions. Before presenting related current research activities and future development, implementation, test and validation plans, the authors describe recent and past achievements in that context. The identification of design-driving requirements is then followed by the technology development plan to address these requirements. This part also includes a description of those ground segment design entities that can be derived from established and proven concepts, such as backup and redundancy, network support, scheduling, archiving and replay, offline processing, multimission flight support, monitoring and control software, etc. The final part elaborates on the test and validation concept of the entire ground segment, which constitutes of the concept of subsequent tests of increasing complexity. Due to the special character of envisaged mission types, particularly adapted tests will however be necessary. Furthermore, for the envisaged two-satellite mission type, special two-crew concepts must be developed and validated through simulations starting from single-satellite simulations to two-satellite simulations involving realtime telepresence operations under most realistic conditions. This publication concludes with an outlook on OOS-related development and qualification activities over the next years and the possible extension on OOS missions in geostationary orbit (GEO).