ARTES-5.1 – ESA Telecom Technology Workplan ... - Emits - ESA

Annex 2Page 202.3 AOCSRef. Activity Title Procurement Policy Budget(KEUR)4C.015(09.153.06)Objective:Description:Autonomous Orbit Determination and Station Keeping Control for Competitive TelecomMissionsPlanned TenderIssueOpen Competitive Tender Type: C 600 2Q 2009 18Estimated Duration(months)The objective of the activity is to define an overall autonomous orbit determination and control (AOCS) system onboard of telecom satellites including manoeuvre planning and executing,with orbit determination using optical navigation or GNSS.As far as the autonomous orbit determination is concerned it shall be based either on an optical navigation sensor or a GNSS sensor. These two sensors shall be traded for best performance,cost and availability, and the activity shall in particular consider the current ARTES-5 contract "GEO Orbit Determination Using an APS-based Navigation Sensor" and the current TRPcontract "Feasibility of GNSS sensors for AOCS applications in GEO and higher altitudes". The activity shall define a suitable orbit determination and propagation scheme, selecting asuitable computation method and defining a solver/estimator that can be easily implemented on-board and meeting the performance needed. A worst-case data outage has to be considered forthe different sensor technologies, including the effect on the overall performance. For the autonomous station keeping control scheme, the activity shall also develop and justify the necessaryalgorithms allowing for a complete on-board manoeuvre planning and execution. The design should be fully fault tolerant and safe and provide full visibility and configurability from anoperational point of view. The strategies shall be verified in a closed loop simulation environment. The activity shall define and demonstrate an overall AOCS architecture, resulting in anautomated and robust platform design, with reduced operational costs and increased availability. The study should focus on an electric propulsion based platform, allowing for more efficientautonomous manoeuvre planning. The output of the activity shall include algorithmic description of orbit determination and station keeping strategies, prototype SW, benchmarking testbed,and simulation tools.Ref. Activity Title Procurement Policy Budget(KEUR)4C.016(09.153.30)Objective:Description:Robust Control Techniques for Large Telecom Satellites with Demanding PointingPerformancePlanned TenderIssueOpen Competitive Tender Type: C 400 2Q 2009 18Estimated Duration(months)The objective of the activity is to improve the overall pointing performance and robustness of large telecom platforms with highly flexible appendages and demanding payload pointing.The activity shall investigate novel control techniques (overall system solutions) for improved pointing and robustness of large telecom platforms. Many larger platforms are suffering inperformance and robustness due to a combination of demanding flex modes from large appendages (solar arrays and antenna structures), together with very tight payload pointingrequirements, and coarse control means due to actuator selection. This is in particular important for more performing missions such as Ka-band and GEO-mobile missions. Several factors arecausing problems in current design solutions (e.g. too large minimum impulse bit, thermal snap of arrays, reflectors during entry/exit of eclipse, low resonance frequencies, etc) and need to beanalysed in more detail. The activity shall analyse the whole system for an optimal solution at system level, considering:1) advanced control techniques (addressing also the modulation/phasing of the control demand);2) dedicated sensors to measure bending and deflection of the appendages in order to allow for an active damping;3) the structural design of appendages (e.g. mechanical design &material selection for reduced elasticity and improved damping);4) active control of the appendage considering embedded dedicated actuators for control of the appendage itself; and5) the typical platform actuators (wheels and thrusters and their sizing, accommodation and interfaces).These options should be considered individually and together. The activity shall revisit current design solutions and identify the limitations faced today. Alternative design solutions shall beinvestigated and provided in the respective areas for an improved overall system performance and robustness, respecting also the unique telecom needs in terms of cost and recurrence. Thesuggested design solutions shall be traded and fully justified through analyses or test as deemed necessary and feasible. The output of the activity shall include design and justificationdocumentation files, software modelling/tools, and test samples (where needed).