Leicester SRC, 3-5 Dec 2007 Systems engineering at detector level Tim Stevenson

Leicester SRC, 3-5 Dec 2007 Elements Requirements engineering Accommodation engineering –Optical –Mechanical –Thermal –Electrical Quality engineering –Verification –Reliability – Risk Mitigation –Serviceability Documentation Model Philosophy

Leicester SRC, 3-5 Dec 2007 Requirements Engineering Science Requirements leading to: –Observatory requirements (pointing, stability, etc) –Chosen detector technology + implementation Position and Envelope Mass Alignment precision Electrical –Power –Noise environment –FE electronics »I/F to separate electronics Thermal Stray light Contamination control Mechanisms Mission requirements –Schedule –Budget allocations –Envelope –Environment Thermal Mechanical Radiation Electrical Attitude disturbance –Reliability Redundancy Life –AIV approach Test and verification facilities Storage, transportation

Leicester SRC, 3-5 Dec 2007 Accommodation Optical requirements and Optical packaging –Position and Volume Vacuum vessel & door/window –Alignment approach –Protection – Door, purging –Mechanisms –Stray light control FP technology specifics –Sealed tube? –Thermal requirements Radiator size, proximity and attitude wrt Sun & Earth Dissipation, detector and FEE Isolation, detector and FEE –Electrical requirements HT discharge precautions, power efficiency Proximity of FEE Relation to main electronics –Radiation protection

Leicester SRC, 3-5 Dec 2007 Quality Engineering Requirements & Design for verification –Testable at all stages –Calibratable and stable Build quality –Traceable materials and parts of known quality –Tried and tested processes Requirements & Design for reliability/confidence –Lessons Learnt from previous similar instruments –Redundancy where possible Failure mode, effect and criticality analysis –Cleanliness –Self test, internal calibration, housekeeping parameters, raw data availability Requirements & Design for serviceability –Spare parts –Access

Leicester SRC, 3-5 Dec 2007 Documentation Hierarchy of requirements Specifications Interface Control Documents Plans Procedures –Assembly –Test –Operations Reports

Leicester SRC, 3-5 Dec 2007 Detector Model Philosophy Deliverable models –Whatever WSO/Lavotchkin requires, STM, EM & FM –Perhaps consider full FS focal plane Development models (dev. function) –Working backwards: Flight Model (calibration) – tested to acceptance levels Ground engineering model (calibration, stability, troubleshooting, software development) –aka Validation Model, qualification levels in test Breadboard model (manufacture & assembly development) Qualification could be done on FM (Proto-flight philosophy – overdesign)