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THEMIS INSTRUMENT PAYLOAD SYSTEM OVERVIEW Dr. Ellen Taylor University of California - Berkeley. Instrument Overview. Instrument Overview Requirement Development and Verification Instrument Payload Requirements Lifetime and Radiation Resource Budgets (RFA #4: Mass and Power Management)
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THEMIS INSTRUMENT PAYLOAD • SYSTEM OVERVIEW • Dr. Ellen Taylor • University of California - Berkeley
Instrument Overview • Instrument Overview • Requirement Development and Verification • Instrument Payload Requirements • Lifetime and Radiation • Resource Budgets (RFA #4: Mass and Power Management) • Thermal • Contamination Requirements - Magnetics, ESC, General • Interface Requirements - ICDs, Harnessing, Grounding • Test and Verification (RFA #10: Test Flow) • Configuration Control (RFA #1: Configuration Control System) • Instrument SCNs, ECRs
Requirement Development • Top-Level requirements developed during Phase A • Concept Study Report provides basic mission concept • Outlines top-level requirements imposed by science and programmatic objectives • Mission requirements flown down (to subsystem level), formalized and documented early in Phase B • All elements of the THEMIS CSR concept and mission requirements reviewed by development team • Mission Requirements Database (MRD) developed and reviewed • MRD finalized and put under Configuration Control at System Requirements Review (SRR), July 2003 • Subsystem Interfaces and Component Requirements further detailed in Phase B • Interface Control Documents between Subsystems and Institutions • System and Subsystem Specifications (Electrical Spec, SOWs, etc) • Mission Plans and Policies (Safety Plan, Risk Mitigation Plan, etc) • Control Plans (Magnetics, Electrostatic Cleanliness, Contamination)
Requirement Verification • Requirement Verification Plans developed in Phase B and C • Development of Performance Verification Matrix ensures a test or analysis is scheduled for all Mission Requirements in MRD • Development of Environmental Test Matrix ensures appropriate testing at component, subsystem and system level • Performance Verification and Environmental Test Plan provides launch and space environments and outlines comprehensive component, subsystem and system level test program • Requirements Compliance and Verification Matrices completed in Phase D • Mission Requirements Document evolves into summary of test program as run • Documents Verification and Compliance Status of all Requirements • Provides direct trace-ability from requirements to test procedures and reports
Lifetime and Radiation • All Total Dose Radiation Testing for Instruments is complete • Replacements found for failed parts • LM 5030 failed, higher power (less efficient) replacement being used • AD 5544 failed, different date code parts that passed 50krad testing being used • GSFC Code 561 completed initial ray trace analysis • Results show additional shielding from Probe composite structure • Wall thicknesses can be decreased slightly to reduce mass • Analysis is being re-run for all instruments with new wall thicknesses
Resource Budgets - Mass From THM-SYS-008 System Mass Budget:
Resource Budgets - Power From THM-SYS-009 System Power Budget:
IPDR Peer Review RFA #4 • TITLE: Mass and Power Management RFA CODE: UCB-4 • REQUESTED BY: Preble • SPECIFIC REQUEST: The THEMIS project should develop a consistent project-wide approach for managing mass and power for the instruments. The plan should define level of mass and power reporting, definitions of key terms (CBE, NTE, margin, contingency, etc.), reporting requirements and frequency (at least monthly?), minimum margin requirements based on maturity and/or point on program (PDR, CDR, I&T start, …, launch). History of key mass and power numbers should be kept and presented to illustrate trends. • RESPONSE: THM_SYS_006b_Systems Engineering Management Plan provides project-wide approach to managing mass and power. THM_SYS_008_Mass Budget and THM_SYS_009_Power Budget is updated monthly and provides resource history.
RFA #4: Resource Tracking and Control From THM-SYS-006 System Engineering Management Plan (SEMP): • In order to ensure that the design will meet Mission Requirements, Systems Engineering controls the following key resources: • Mass (dry mass, delta-V, propellant margin) • Power • Telemetry (data budget) • RF Link Margin • Resource Requirements have been flowed down to the Probe, Probe Carrier, and Instrument Payload in the MRD. Each Instrument and Probe Subsystem includes: • Current Best Estimate (CBE), updated periodically as the design matures • Contingency, based on design maturity, following schedule outlined in SEMP • System not-to-exceed allocation (current CBE + contingency) • Sum of not-to-exceeds is less than the System Capability providing Program Managers Margin held at UCB • All Resources closely tracked throughout program • Continually tracked and updated by System Engineers (Probe and Instrument) • Periodically (once a month) reported to and reviewed by MSE and PM • Periodically (once a month) reported to NASA Mission Manager
RFA #4:Resource Margins From THM-SYS-006 System Engineering Management Plan (SEMP): • Contingency is defined as % of resource added to an estimate as a provision for uncertainty. • Contingency is based on the level of maturity: 1. Concept: 25% • 2. Design: 15% • 3. Prior Build: 7.5% • 4. Fabrication: 4% • 5. Flight Build: 2% • Contingency % that doesn’t meet schedule triggers re-allocation and possible release of PM Margin. • Program Managers (PM) Margin is defined as the amount of resource remaining when estimate plus • the associated contingencies are subtracted from the available quantity. The project will maintain • appropriate margin at each phase, as shown: 1. Phase A Concept: > 30% • 2. Preliminary Design Review (PDR): 15% to 20% • 3. Conceptual Design Review (CDR): 10% to 15% • 4. Pre-Environmental Review (PER): 5% to 10% • 5. Pre-Ship Review (PSR): 2% to 5% • PM Margin % that doesn’t meet the Margin Schedule will trigger a project level risk mitigation • plan, resulting in possible descope of mission objectives.
RFA #4: Instrument Mass History From THM-SYS-008 System Mass Budget:
RFA #4: Instrument Power History From THM-SYS-009 System Power Budget:
Instrument Power Modes • SAFE POWER MODE is entered on reset (power-on), by ground command, or in response to flag in Probe status field (power-down imminent) in preparation for IDPU load shed • Power-on state, saves power and the contents of SRR • IDPU Core Systems (LVPS, PCB, and DCB) are powered on, all instruments off • Power: 6.2W CBE, 7.1W Mature • LOW POWER MODE is entered by ground command in preparation for maneuvers (FGM data for attitude determination) or in response to flag in Probe status field (low-power) in case of low power condition • IDPU Core Systems (LVPS, PCB, and DCB) and FGM are powered on, all other instruments off • Power: 6.9W CBE, 8.0W Mature • SCIENCE MODE (Nominal) is entered by ground command (instruments are powered on one at a time during early operations) • Normal operating state, full science data collection • IDPU Core Systems, instrument sensors and associated electronics are powered on • Power: 12.7W CBE, 14.8W Mature • ENGINEERING MODE is entered by ground command in preparation for early operations (instrument health and safety diagnostics) and special case instrument operations (boom deploy, high voltage turn-on) • Higher engineering rate and additional telemetry points telemetered • Operational only, typically during ground contact
Resource Budgets - Data From THM-SYS-010 Instrument Data Budget (Detailed Rates):
Data Volume From THM-SYS-010 Instrument Data Budget (Summary):
Contamination • Magnetics Contamination Control Program in place • Magnetics Control Board Established (UCB, UCLA, Swales), Bi-weekly meetings • Main Offenders List, Magnetics Budget, and Component Tracking Spreadsheet • Magnetic Verification and Test planning in progress • ESC Contamination Control Program in place • ESC Specification detailed (see response to IPDR RFA #8 in EFI presentation) • Exposed Insulator Budget and Tracking Established • Contamination Control Program in place • Contamination Control Plan Developed and reviewed by Swales
ICD Document Revision List From THM-SYS-000 Document List:
Verification and Test • See Response to RFA #10
IPDR Peer Review RFA #10 • TITLE: Test Flow RFA CODE: UCB-10 • REQUESTED BY: Preble • SPECIFIC REQUEST: • We recommend that UCB define the development, engineering model, qualification, and acceptance testing approach for all of the THEMIS instruments. We think that this could be contained in an I&T test plan. For starters, however, we recommend that each instrument team (or the project-level system engineering team) develop a flow chart identifying the testing that will be conducted. The conditions of the testing such as temperature, vacuum or air, cycles, etc. should be added when available. • Response: THM_SYS_005d_Instrument Payload Verification Plan and Environmental Test Specification provides the test plan for all instruments. Flow charts for each instrument is contained in the plan. The THEMIS Environmental Test Matrix contains specific test conditions such as vacuum or air, number of cycles, etc. • *I&T Flows presented in Integration and Test Presentation tomorrow afternoon (Rick Sterling)
IPDR Peer Review RFA #1 • TITLE: Configuration Control System RFA CODE: UCB-1 • REQUESTED BY: Heetderks • SPECIFIC REQUEST: • The THEMIS project should establish a project wide Configuration Control System. It would be preferred would be to meet the full requirements of the Midex PAR, but at the least they should: • Identify a Configuration Manager (CM) who has responsibility for maintaining native files of all controlled drawings and documents in a single location. • The MSE is responsible for maintaining all controlled documents. The MechSE is responsible for maintaining all controlled mechanical drawings. • Establish a set of allowed drawing and CAD systems for native files • Engineering database drawing control using PDMWorksTM • Establish a common numbering system for all THEMIS drawings and documents, and pull all drawing numbers from a common registry. • THEMIS number system (THM_XXX_TTT_NNNR_title) provided in Appendix A of THM-SYS-011b_Configuration Management Plan.
IPDR Peer Review RFA #1 • TITLE: Configuration Control System RFA CODE: UCB-1 • REQUESTED BY: Heetderks • d. Establish a formal ERO/ECO system for release of all new drawings and revisions of existing drawings. This should include a formal check as well as sign off by at least the System Engineer and Mission Assurance Manager. • Formal Engineering Change Request/Notice (ECR/ECN) system in place as describe in THM-SYS-011b_Configuration Management Plan using form provided in Appendix D. Form includes signature blocks for Lead Engineer, Mission Assurance Manager, Systems Engineer and Project Manager. • Establish a location where latest the Rev of all drawings are available to everyone on the project. Suggest use of a public server. • Current revisions of all released documents are placed on THEMIS public ftp site. THM-SYS-000_Document List provides folder location and links.
RFA #1:Configuration Management • From THM-SYS-011 Configuration Management Plan: • Configuration Identification • Provides schedule of data and document release to facilitate interface and interaction between subsystems and subcontractors • Configuration Accounting • Controlled document, drawing and schematic revisions, ensure formal review process for changes, maintain history • Engineering database control for drawings using PDMWorksTM • Security: password protected, typical UCB network protection • Controlled Access: only authorized user can view, add or delete (Read, Write permissions), only one owner at any one time has ability to change document and check it back in • Controlled Revision: automated revision control and history tracking, all previous revisions kept within database • Accountability: maintains log of all persons responsible for any change, addition, or deletion to the database • Configuration Assurance and Verification • Accomplished by end-item inspection and documentation review to determine product compliance with the latest approved baseline • Responsibility relies mainly with the MAM • The THEMIS Performance Assurance and Implementation Plan (PAIP) provides the plans for inspection and test, requirements for end-item acceptance, and procedures for numbering and serializing accepted parts, subassemblies, and assemblies
RFA #1: Configuration Management • From THM-SYS-011 Configuration Management Plan: • Configuration Control • Formal change approval/disapproval implemented to protect against uncoordinated/ unauthorized change • System Level Change process involves an Impact Assessment (IA) followed by a formal approval process. The IA is attached a System Change Notice (SCN) and submitted to the Configuration Control Board (CCB) for approval. Subsystem Level (Instrument Payload) change process involves ECR/ECN system • Impact Assessments (IAs): Includes rationale for a change to baseline, summary of impact • System Change Notices (SCNs): Prompts a systematic evaluation of the proposed changes • Engineering Change Requests/Notices (ECR/ECN): Request and Notice of change. • Problem Failure Reports (PFRs): Initiated after a problem is found, documents impacts, assesses alternatives and provides recommended courses of action • Configuration Control Board (CCB) used for Level 1,2,3 changes • Subsystem trades (level 4) can be made within the resources of the subsystem. Systems Engineer insight and involvement. • Trades that impact subsystem/system interfaces or resource allocations (level 3/level 2) require concurrence by the Configuration Control Board (CCB): Principal Investigator, Project Manager, Mission Systems Engineer (MSE), Probe Systems Engineer, Mission Operations Manager and affected Team Leads. GSFC Mission Manager insight. • Trades that impact Level 1 baseline science/programmatic requirements must include approval by Principal Investigator and GSFC Mission Manager. • Trades that impact Level 1 minimum science/programmatic requirements must include have approval by NASA HQ.
SCNs – affecting Instruments • SCN 001 Propulsion Tank Size Change • Initiated to improve propellant margins by 11.5% • Required EFI spin plane booms to be ‘canted’ by small angle • SCN 004 SST Envelope Increase • Initiated to ensure full SST FOV is accommodated • Required reduction in minimum static clearance between probes kept by Swales • SCN 005 ACS Stability • Initiated after dynamic simulations • EFI axials shorted and radials lengthened • SCN 006 Boom Cant Angle • Initiated after detailed solar array shadow analysis • Mag Booms canted to reduce shadow on Solar Arrays • SCN 009 EMC/MAG Testing • Initiated to ensure science requirements are verified at system level • EMI/EMC/MAG Testing at GSFC added to Probe 1 Environmental Test Program
