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

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Annex 2Page 25Ref. Activity Title Procurement Policy Budget(KEUR)4E.037(09.153.32)Objective:Description:Planned TenderIssueUltra Light Compact Shock Damping Device Open Competitive Tender Type: C1 400 Priority 2 15Estimated Duration(months)This activity is to design, manufacture and characterise (test) a breadboard of an Ultra Light Compact Shock Damping Device intended to be used in combination with inertial deploymentsystems (e.g. ULMAAS). The proposed Ultra Light Compact Shock Damping Device is intended for implementation at the deployment hinge between antenna and spacecraft. It should betuneable to meet the needs of the new generation of telecom antennae and match with the interfaces to the antenna or its trim mechanism.A new generation of compact telecom S/C with light weight antennas is being developed for the GEO commercial market. New inertial deployment systems, e.g. ULMAAS, and compacttrimming mechanism are being developed to meet the demands of this sector. One of the toughest challenge of inertial deployment is meeting the high torque requirements and the highstiffness in deployed configuration while minimising the shock levels at the end of the deployment. This activity centres on the development of a compact damping system which can beintegrated to the antenna or trimming mechanism I/F and dampens the shock to minimal levels. In a first step a review of state-of-the-art damping devices and a trade-off of shock controlsystems for space applications will be performed. In parallel, the requirements of new telecom antenna assemblies will be reviewed. This part will conclude with a consolidated set ofrequirements including expected shock damping characteristics, stiffness, envelopes, mass and all other performance criteria for the device. The damping system will be developed to meet theconstraints of the specification, performance being verified by analysis and built breadboard. Its shock damping efficiency will be measured both at beginning of life and after acceleratedageing. The ability of the system to comply with the typical environmental, lifetime and positioning requirements of a selected target application will be assessed and, where applicable, tested.The versatility of the system for larger payloads and alternative deployment kinematics will be tested and correlated to previous analysis.NOTE: This activity has been designated as "Priority 2". Priority 2 activities will only be initiated on the explicit request of at least one delegation.
Annex 2Page 262.6 Power SystemRef. Activity Title Procurement Policy Budget(KEUR)4F.020(06.153.72)Objective:Description:Planned TenderIssueQuenching Circuit for Solar Array Power Arcing Events Open Competitive Tender Type: C 200 3Q 2009 12The objective of this activity is to design, manufacture and test a breadboard of a Quenching Circuit for Solar Array Arcing Events.Estimated Duration(months)Geosynchronous telecommunication satellites having system power levels in the tens of kilowatt range, now have typically power bus voltages of 100 volts or greater. If under sun illuminatedconditions of the solar array, any conductive particles bridge across opposite polarity electrical conductors that are carrying electrical power (i.e. adjacent solar cells, bus bars, or slip rings),any initial current flow will very likely rapidly evaporate such particles. What happens next however is very unpredictable. Either following the fusing of the particle, any residual arc maysimply extinguish, or alternatively if sufficient plasma, heat and material damage has already occurred, a sustained arcing event can be initiated. If this latter situation proves to be the case, theextreme localised heat generated by the arcing event can rapidly degrade any local insulating barrier and quickly result in a permanent short circuit condition, resulting in a dramatic powerloss for the satellite.A possible solution for the suppression of arcing is one, which will detect the initial short-circuit/arc and then allow a short delay time, so as to give a chance for any short-circuiting materialto evaporate. If the phenomenon persists beyond this short delay, any maintained arcing will then be quenched by removing the applied voltage for a much longer period by driving on theappropriate array section dump of the power system shunt regulator. Of key importance in this activity will be the ability to configure this circuit feature as simply as possible within existingpower dump stages of the shunt regulator. Within this proposed activity the contractor will be asked to design, manufacture and test a breadboard concept of a reliable arc quenching circuitconcept to be integrated within individual power dump stages of a Sequential Switching Shunt Regulator (S3R).Ref. Activity Title Procurement Policy Budget(KEUR)4F.039(09.153.33)Objective:Planned TenderIssueSolar Array Charging Voltage Limited by Neutralizer Open Competitive Tender Type: C 200 3Q 2009 12Estimated Duration(months)The objective is to study the feasibility of using a charge neutralizer mounted on the S/C body to reduce the overall solar array charging voltage to minimize the risk of damaging ESD onsolar arrays (primary and secondary arcs). The potential impact of such a neutralizer on the lifetime, performance of the solar array (such as contamination or sputtering effects on solar cellinterconnections) and the spacecraft attitude control management shall be assessed.Description:Solar arrays operating in GEO are typically charged to very high potentials resulting in ESD. Under various conditions primary arcs trigger damaging secondary arcs. Several in-flight solararray anomalies/failures were attributed to this phenomenon. It is known that the operation of ion engines on GEO S/C is changing the S/C floating potential. Having this in mind they mightalso be used to limit the max solar array charging potential.The main task of this activity is to find out if it is possible to use ion engines/neutralizers, to limit the maximum charging potential of a solar array. It shall be investigated if AOCS engines(modified either in performance and/or orientation) can be used or if dedicated units (identical to an AOCS engine or with equivalent performance) are required. Please note, that thisparticular phenomena and resulting potential solution of the problem is exclusively applicable for solar arrays in GEO.
Page 1 and 2: March 2009ARTES-5.1 - ESA Telecom T
Page 3 and 4: Annex 1Page 1ANNEX 1SUMMARY TABLE F
Page 5 and 6: Annex 1Page 3ActivityRef.Title Cost
Page 7 and 8: Annex 2Page 21. SYSTEM/NETWORKS/PRO
Page 9 and 10: Annex 2Page 4Ref. Activity Title Pr
Page 15 and 16: Annex 2Page 101.2 PropagationRef.al
Page 17 and 18: Annex 2Page 12Ref. Activity Title P
Page 19 and 20: Annex 2Page 142. SPACE SEGMENT - GE
Page 21 and 22: Annex 2Page 162.2 Propulsion System
Page 25 and 26: Annex 2Page 202.3 AOCSRef. Activity
Page 27 and 28: Annex 2Page 222.4 Thermal SystemRef
Page 58: Annex 2Page 53Ref. Activity Title P

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