Systems Engineering

1. Systems Engineering Mike Pryzby Swales Aerospace August 16-17, 2005

2. LRO Systems Team

3. LRO Systems Engineering Implementation Approach • SE is integrated into project as defined in our SEMP in accordance with GPR 7120.5 and tailored to reflect the successful approach taken by the core LRO team on past missions • Key SE documents include; SEMP, Golden Rules, MRD & Siblings including Electrical, Mechanical, Thermal, and Pointing specifications, Allocations and Con Ops documents • Gold used by subsystems as requirements at L2/L3. Compliance matrix in process, due at PDR • SE activities defined by phase in our SEMP, phase A&B presented today • Evidence of our SE process is the content of this SRR

4. Preliminary Analysis - Phase A Understanding the Objectives - Understand and define Level 1 science requirements; Identify full and minimum mission reqs - 1st draft of Level 1 reqs for review at MDR - Validate Level 1 requirement and show flowdown to Level 2 requirements at MD Operations Concept Development - Identify and define LRO Mission Phases - Complete preliminary draft version of LRO Operation Concept Document Architecture & Design Development - Review LRO ORDT Report & previous concept studies - Identify key LRO design drivers & perform trade studies of various implementation design concepts - Define architecture design concept and balance with reqs and ops concept Requirements Identification & Management - Define draft Level 2 MRD reqs & demonstrate flowdown & traceability to Level 1 reqs at MDR - Detailed walkthrough of MRD Level 2 reqs traceability and assignment at SRR - Initial entry of MRD Level 2 reqs into DOORS database for mgmt and tracking - Define initial LRO Doc Tree, detailing subsystem reqs documentation structure & responsibility Validation & Verification - Perform initial trade studies and fold into initial system architecture design concept - Demonstrate MRD Level 2 reqs traceability to Level 1 reqs and to implementation design concept at SRR Interfaces & ICDs - Begin initial discussions across instrument and subsystem lines on interface design concepts as part of initial architecture design baseline effort - Identify proposed ICD documents within LRO Document Tree Mission Environments - Complete initial radiation environment assessment and document in draft radiation white paper - Distribute contamination questionnaire to Instr, establish contamination working group, and complete draft contamination assessment - Define initial flight operational & test environments in Systems Verif & Envi Def document Technical Resource Budget Tracking - Establish formulation resource allocations as part of architecture design concept investigations - Baseline resource allocations at end of Phase A within SCR allocation margins - Bring resource allocations under CM at beginning of Phase B Risk Management - Establish Risk Management Plan & Procedures & identify, classify, & report initial risk items - Begin initial fault tree analysis and reliability block diagrams and use to optimize design concept System Milestone Reviews - Hold Mission Design Retreat (MDR) to review Level 1 reqs and initial design concept - Hold System Reqs retreat (SRR) for detailed walkthrough of Level 2 MRD reqs and demonstrate flowdown & traceability to Level 1 reqs - Hold SRR/SCR for external review team- acts as review milestone for progression Phase B Configuration Management & Documentation - Define LRO document tree and define subject, when due, and who responsible for each document System Engineering Management Plan - Complete draft SEMP and plans for Phase A definition of “single system design” concept - Update SEMP for Phase B activity plans to “design the right system” Phase A Plans and ActivitiesLRO SEMP (431-PLAN-000005) System Engineering Lifecycle Activities MatrixAll Completed 

5. System Definition - Phase B Understanding the Objectives - Level 1 Science Reqs competed & signed off by NASA HQ; Includes minimum mission reqs - Track any changes to Level 1 reqs (changes req NASA HQ approval) - Refine LRO Mission Phases definitions and LRO Operation Concept Document Operations Concept Development  Architecture & Design Development ◘ - CM block diagram of LRO architecture design concept - Begin preliminary system and subsystem design process - Begin conceptual breadboard design process; use breadboards as testbeds and for interface testing across ss for risk reduction Requirements Identification & Management - Define draft Level 2 MRD reqs & demonstrate flowdown & traceability to Level 1 reqs at MDR - Detailed walkthrough of MRD Level 2 reqs traceability and assignment at SRR - Initial entry of MRD Level 2 reqs into DOORS database for mgmt and tracking - Define initial LRO Doc Tree, detailing subsystem reqs documentation structure & responsibility Validation & Verification ◘ - Update MRD Level 2 reqs with verification information and use process to check validity of reqs Interfaces & ICDs - Baseline and release initial documents and ICDs on LRO Document Tree Mission Environments◘ - Update contamination assessment and complete draft Contamination Control Plan - Begin evaluation and tracking of parts and materials for use in identified flight environment - Update flight operational & test environments in Systems Verif & Envi Def document Technical Resource Budget Tracking - Bring resource allocations under CM at beginning of Phase B within appropriate margins - Track and control resource allocations to complete Phase B within PDR margin allocations Risk Management ◘ - Complete initial FMEA of preliminary design concept and fold results back into design - Update fault tree analysis and reliability block diagrams & use to further optimize design concept - Ongoing identification, classification, & reporting of risk items per Risk Mgmt Plan & Procedures System Milestone Reviews ◘ - Hold subsystem peer reviews and PDRs to review Level 3 reqs and initial design concepts - Hold Mission PDR for external review team- acts as review milestone for progression Phase C Configuration Management & Documentation - Initiate CCB process to address changes to configured documents - Bring Level 1 Reqs, MRD Level 2 Reqs, and Level 3 Subsystem spec under CM System Engineering Management Plan ◘ - Update SEMP for Phase C Design activity plans to ensure system is “implemented right” Phase B Plans and Activities LRO SEMP (431-PLAN-000005) System Engineering Lifecycle Activities Matrix Black –done, ◘Green – In progress

6. Requirement Capture and Control Process

7. Review Process ??? • Peer Reviews discipline driven, ingrained as an institutional process at GSFC and our PI institutions • Project mandated peer reviews by SE and management as deemed necessary • Examples include; FPGA’s, LROC Optical Design, PDE Architecture • Peer Review Process in accordance with GPR 8700.6A and LRO Peer Review Plan. • SE attends and assigns actions as warranted • Project mandated/schedules as necessary, part of GSFC process across all project elements • Team comprised of technical experts, internal and external as required • Desire to keep review team through project lifecycle • Contested RFAs tracked in Project Action Item database • PDR, CDR, PER, PSR etc content defined in our SE plan and controlled by LRO IIRT Review Plan (431-PLAN-000007)

8. Validation and Verification • Validation process includes use of DOORS to insure no orphan requirements and proper traceability and flow down • Verification is part our CM process and a mandatory section of each requirements document • Verification matrix using DOORS database will include the following fields • Ownership to identify which individual is responsible for verifying this requirement, as well as those others with a significant effort in the verification activities. • Verification method; Inspection / Analysis / Demonstration / Test • Description of type of test, if needed • Verification Documentation to show where the requirement is verified • Verification Result Summary • Mission Verification Plan will define overall process and plan for completion.

9. Safety Req. Level 2 Req. Level 3 Req. … … Mission Success Criteria Advanced Functional Schematics (concept) Advanced Functional Schematics (concept) Degraded Mission Criteria Identify Mission Success & Degraded Mission Performance Identify Mission Success & Degraded Mission Performance Risks Risks Trades Trades Req. Chg Req. Chg Risk Management Intertwines with Mission Success & Reliability to Minimize Risk • Mission Success Engineering, Reliability Engineering, and Risk Management coordinating an integrated process • Capture spacecraft concept/design using Advanced Functional Schematic (AFS) • Identify Mission Success and Degraded Mission performance of spacecraft concept. • Criticality & Degraded Mode Analyses • Critical Items List, FMEAs, RBDs, FTAs, & PRA • Safety & Reliability Analyses • Mission Success vs. Implementation Decisions • Risks to Mission Success assessed • Trades Space (Requirements vs. Implementation Considerations) • Recommend changes to level 2, 3 and 4 requirements that improve mission success • Risk inputs provided to Systems Engineering & Project Management

10. Architecture Optimization from Single String to Selective Redundancy • Mission Success requirements flow top down to individual subsystems/elements • Advanced Functional Schematics (AFS) capture big picture; end to end view of spacecraft systems and architecture. • Spacecraft operations, mission modes & phases, timing, event durations and criticality considered. • Criticality of risk factors to mission success and residual risks considered • Apportionment of requirements to improve mission success • Hardware Requirements, Independence, Fault Tolerance, Reliability Apportionment

11. Driving System Trades