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View File - University of Engineering and Technology, Taxila

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Risk control <strong>and</strong> monitoring measures, including technicalperformance measurementRisks associated with cost <strong>and</strong> schedule performance measurement5. Environmental factorsThe prime environmental problems a satellite encounters are electromagneticcharges, radiation, pressure differential, solar radiation or flare, <strong>and</strong>other artifacts like meteoroids. The space environment is composed <strong>of</strong>electromagnetic <strong>and</strong> corpuscular radiation. Electromagnetic radiation comesmainly from the sun <strong>and</strong> exhibits the properties <strong>of</strong> waves travelling at thespeed <strong>of</strong> light. Corpuscular radiation originates both in the sun <strong>and</strong> in galacticspace <strong>and</strong> consists <strong>of</strong> charged <strong>and</strong> uncharged particles whose velocity is theproduct <strong>of</strong> the mechanics <strong>of</strong> generation. In essence, environmental conditionsduring launch <strong>and</strong> in space affect mechanical <strong>and</strong> electrical design as well asreliability consideration.Upon completion <strong>of</strong> these analyses, an operational concept document(OCD) is produced, whose main purposes are to1. Specify the system characteristics from an operational perspective.2. Ensure that users underst<strong>and</strong> the system goals.3. Provide guidance for development <strong>of</strong> subsequent system definitiondocuments such as system specification, interface specification,product specification, test specification, etc.4. Describe the user organization <strong>and</strong> mission from an integratedsystem <strong>and</strong>=or user point <strong>of</strong> view.It is important to note that, at this system-level design, the customer’s approvalmust be gained for the OCD to become valid because the customer is theowner <strong>of</strong> the OCD. The production <strong>and</strong> subsequent approval <strong>of</strong> the OCD is thefirst step in clarifying the customer’s needs <strong>and</strong> establishing the customer’srequirements as well as providing practical guidelines on how to apply theseoutlined requirements for system analysis <strong>and</strong> design.2.6.4 System Design: Bus, Electrical, <strong>and</strong> MechanicalThe satellite bus system design must consider the beam pointing accuracy,velocity, <strong>and</strong> angular range.Copyright © 2002 by Marcel Dekker, Inc. All Rights Reserved.

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