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Systems Engineering. Chad Fish chad.fish@sdl.usu.edu 435-797-0469. Presentation Overview. Key System Requirements System Design System Operation Technical Resources and Error Budgets Post-PDR System Changes Technical Risks Technical Coordination Summary Supplementary Material
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Systems Engineering Chad Fish chad.fish@sdl.usu.edu 435-797-0469
Presentation Overview • Key System Requirements • System Design • System Operation • Technical Resources and Error Budgets • Post-PDR System Changes • Technical Risks • Technical Coordination • Summary • Supplementary Material • Error Budget Models • Level 3 Requirements Compendium
Science Objectives • SOFIE will support AIM mission in study of PMCs and the environment in which they form. SOFIE will use differential solar occultation to measure: • Five gaseous species (H2O, CO2, O3, CH4, NO) • Temperature • Particle extinction at 10 wavelengths • Each SOFIE channel uses two detectors to make three measurements: • Strong band absorption • Weak band absorption • Difference signal (weak band – strong band = ΔV) Remove interference and reduce noise!
System Requirements (Cont) SOF 174 : Measurement Bands SOF 183 : Radiometric SNR
Instrument Unit Purpose: Perform science signal detection & FOV pointing and stabilization control Contains: Opto-mechanics Mirrors, filters, beam splitters, field-stop, chopper [1.8’ x 6’ Inst FOV; 32º x 24º Glint FOV] Detector assemblies (includes TECs and PreAmps) Steering mirror [4º x 4º FOR] Sun sensor electronics and software [2º x 2º FOV] Electronics Unit Purpose: Perform system command and control, communication, signal conditioning, and power conditioning Contains: Command and data handling electronics and system software Position and stabilization control electronics and software Communication, signal conditioning, and mechanisms control electronics and software Thermal sensor, TEC thermal control, and housekeeping electronics Power conditioning electronics Design Description
Instrument Unit Radiator Pin pullers Aperture cover Steering mirror Alignment cubes N2 Purge Witness Mirrors (x4) Circular connector interfaces Dynamic Envelope: 16.2 x 26.3 x 29.5 inches SC Isolator Feet (eff 14° wedge)
SOFIE Instrument Unit (cont) POINTING AND STABILIZATION CONTROL Sun Sensor SIGNAL DETECTION Channel Separation Module
SOFIE Electronics Unit Electronics PCBs Top Connectors and Cabling SC Radiator Panel Power Conditioning Dynamic Envelope: 16.2 x 26.3 x 29.5 inches
Modes of Operation Survival
Science Mode (cont) Maximum science measurement duration (AQR, DATA) = 155 seconds
Solar Scanning and Maneuvering Vertical Scanning FOV Azimuthal Offsetting (bore sighting)
Science Data Products 2 1 1 1 El Az
System Technical Resources & Error Budgets
Technical Resources Resource margin and reserve managed by mission
Changes since PDR SMA Caging Mechanism Removed Wedge Removed Radiator Reshaped Cable Ports Relocated
Changes since PDR (cont) Repositioned in SC and Radiator Removed Electronics Power Conditioning Redesigned Detector Packages now Non-hermetic
Technical Risks RISK ID = SOFIE_RISK_4 SOFIE depends upon an active pointing system to provide the required sun pointing accuracy and precision. The active pointing and control system algorithm may be unable to provide the required sun pointing accuracy and precision and the science capability would be degraded. CRITICALITY Green MITIGATION Extensive prototype and protoflight testing will be conducted.
Technical Coordination – SDL Design Processes • Engineering Design and Development • System Design • QP0401 • Software Design • QP0406 • Document Control and Configuration Management • Document Control • QP0501 • Software Configuration Management • QP0403, SOFIE Software Configuration Management Plan • SDL to maintain up-down information flow • Waivers, Problem Failure Reports (PFR) • QP1301
Technical Coordination – Internal Peer Review • Review follows Breadboard/Prototype design phase • Includes SDL members both internal and external to SOFIE • System and component level • Following review, design placed in configuration control
Designs are mature and provide margin on system requirements Technical resources are being managed and tracked Error budgets are being managed SE Summary
Radiometric System Requirements SOF 174 : Measurement Bands SOF 183 : Radiometric SNR
Radiometric Model Error Budget Optical Input Path
Radiometric Model Error Budget (cont) Optical Math Model Transfer Function