# Presentation: 871867

## Section 13

_***Section 13***_
***Spacecraft Systems Management Approach***

*** ******. . . Mark Perry***
*Swales Aerospace, Inc.*

## Contents

***Contents***

***Requirements Verification***
***Process***
***Matrix***
***EO-1 Approach to Systems Engineering***
***Risk Management***
***Critical Resource Management***
***Mass, power, and telemetry bandwidth***
***Configuration Management***
***Drawings - Integration & Test Procedures***
***Software***
***Spacecraft Quality Assurance***
***Design & Fabrication***
***I&T Program ***
***I&T Staffing***

## Requirements Analysis

***Requirements Analysis***

***Traceability***
***Lowest level requirements traced back to the higher level requirements from which they were developed***
***Level One requirements tracked to source project document (EO-1 Project Plan)***
***Level Two and Three requirements become Derived to satisfy a Level One requirement or Allocated by an Interface Control Document***
***Verification***
***Each lowest level requirement, for a given function, is verified by Analysis or Test & Evaluation***
***The requirement is traced to the Verification requirement (Test Plans) in addition to the verification performed (Test Procedures, Analysis Reports, and Work Order Authorizations)***

## Requirements Verification

***Requirements Verification***

***System-level 1, 2 and 3 and subsystem derived requirements***
***Verified during integration and system tests***
***Functional requirements verified using functional test after each environmental test and each move***
***Performance requirements verified using CPT and other special tests before and after environmental testing***
***Environmental requirements***
***Verified at box and satellite level ***
***See Environmental Verification Matrix***
***Software***
***Verified by developer, by EO-1 team in S/W lab, and on spacecraft in acceptance tests, regression tests, and CPT***
***Separate S/W verification matrix***

## Requirements Matrix

- LEVEL I REQUIREMENTS
- (Sample)

- LEVEL II REQUIREMENTS
- (Sample)

- LEVEL III REQUIREMENTS
- (Sample)

*REQMT ID Interpretation:   Example 02.3.12*
*	**Interpretation:  02 - This requirement is a level 2 requirement.*
*	**                         **3 – The requirement is item number 3 within the L-II requirements.*
*	**                         **12 – This requirement is traceable to the next higher level requirement (L-I in the example) item number 12.*

## Program Constraints

***Program Constraints***

***EO-1 development was driven by cost and schedule***
***Design to cost: existing architecture and hardware, redundancy implemented to balance risk of single-string design***
***Build to cost: limited documentation, de-scope if necessary, rapid decisions, etc.***
***Cost and schedule are as important as performance***
***If cost or schedule threatened, performance trades considered***
***Due to aggressive planning to incorporate the most advanced technologies, de-scopes occurred as the mission progressed***
*ALI WIS and GIS detectors*
*1 Gb/s fiber optic data bus*
***The early design was realistically evaluated with respect to program constraints: “buy-ins” not considered on EO-1***

## Approach to Systems Engineering

***Approach to Systems Engineering***

***Success depended on ***
***Active interface control and monitoring***
***Quick decisions: key personnel using engineering judgement***
*Example: quick incorporation of Hyperion*
***Limited system documentation, particularly on design process***
*Lesson-learned: earlier documentation (e.g., systems schematics, C&T handbook) would have saved time during integration & tests*
***When evaluating system trades, took advantage of mission goal: technology development.  For example, EO-1 is in standby mode for 90% of the mission.***
***Selected redundancy implemented only on mission-critical systems consistent with Project constraints***
***Solar array release mechanism, 1773 data bus, power harnessing, separate ACS safehold processor, main-computer memory source (EEPROMS), propulsion heaters***
***Thorough and careful Integration & Testing***
***Detailed documentation of all integration procedures & anomalies***
***Caught errors not discovered during rapid development phase***

## Delegated Responsibilities

***Delegated Responsibilities***

***Managers and systems engineers identified and empowered lead engineers who have the initiative, capability, and dedication to take full responsibility for their system: performance, cost, schedule, and interfaces***
***Responsible for all phases of development: design through on-orbit checkout***
***This distributes the systems-engineering responsibility and ensures several checks on each interface ***
***Minimizes the number of dedicated systems engineers, reducing cost***
***For example, the EO-1 engineer responsible for the structure also acts as the mechanical systems engineer: confirming interfaces and doing the system layout***

## Spacecraft Level Risk Management Process

***Spacecraft Level Risk Management Process***

***Risk Identification Sources***
***Schedule***
***Cost***
***Performance***
***Recent anomalies on other Programs***
***During developments, risks identified, reported monthlies, and tracked to completion***
***During I&T, risks identified and tracked through PR system***

***Examples***
***Limited Documentation***
*Use of core design personnel from development through operations*
*Use of MAP design personnel during I&T process*
***Single String Design***
*Some elected redundancy under program constraints*
*Incorporation of fuse plugs for non-essential loads*
***Schedule/Cost***
*Descopes*
*ALI WIS and GIS detectors*
*1 Gb/s fiber optic data bus*
*Augment team with GSFC & MAP personnel*

## Sample of Monthly Risk Matrix

## Management of Critical Resources

***Management of Critical Resources***

***Preliminary allocations developed for the Systems Design Review***
***Included reserves for mass and power and telemetry***
***Resource use constantly monitored, with weekly reports***
***Deviations reported by subsystems as soon as discovered***
***Systems reallocates when necessary***
***EO-1 allocations revised several times***
***In trades to reduce cost or shorten schedule***
*Example: allocate additional mass to structure to permit switching from a composite structure to an aluminum structure*
***In response to technical difficulties***
*Example: ALI required additional mass to meet stiffness requirement.*
***After as-built characteristics released reserve***
***Mass: after switch to Delta L/V, total mass became weak constraint***
***Telemetry: sufficient bandwidth for nominal and emergency ops***
***Power: the most-critical resource, particularly after adding Hyperion***

## EO-1 Mass

***Subsystem weights were measured prior to installation on the satellite & the solid model is updated based on latest measured weights***
***Inertia properties are calculated from solid model***
***Final satellite mass will be within flight allocation***
***Allocation: 588 Kg***
***Final mass: 573 Kg, 2.5% below allocation***

## EO-1 Power Use

***EO-1 Power Use***

***Rack up of “as measured” powers for total system power for DCE and Standby orbits***

## EO-1 Telemetry Bandwidth Use

***EO-1 Telemetry Bandwidth Use***

## CM Drawings and I&T Procedures 

***CM Drawings and I&T Procedures ***

***SAI EO1-CM-PLAN-001 Configuration Management Plan for the EO-1 Spacecraft (265 I&T Plans/Procedures not including Test Directives)***
***Covers the CM  Process for all Swales generated Drawings and Hardcopy Test Procedures specific to the EO-1 Program***
***Process audited by outside ISO9001 certification team and GSFC Code 300 (no discrepancies or changes required)***
***Subcontractors rely on in-house CM  Plan/Procedures***
***Payload ICDs managed by GSFC CM***
***All documentation reviewed and signed before work begins***
***Drawings updated following fabrication and assembly***
***Procedure redlines incorporated before re-running procedures***
***CM  personnel co-located with I&T team to reduce process time***
***Automated Test Procedures ***
***STOL Procedures managed by EO-1 Lead Test Conductor.  Changes to procedures require Data Base Change Request (DBCR) form with review by system/subsystem engineer.  QA verifies that DBCR has been written prior to PR closure.***

## EO-1 Software CM

***EO-1 Software CM***

***Visual SourceSafe***
***Flight Software stored in separate libraries***
***Problems & changes to source code documented with EO-1 Problem Test Report (PTR) number***
***Builds labeled on delivery to FSW Test Lab***
*After testing, code is copied from string by CD&H CM Manager*
*If needed, old builds can be retrieved from VSS*
***VSS can generate history report of code changes for each file***
***PTR System***
***Changes to code done via PTR***
***Problems, design issues, and program improvements are logged***
***MAP PTRs tracked for issues applicable to EO-1***
***Delivery to Spacecraft for Test***
***Version Description Document (VDD) delivered w/ WOA for each new build & includes:***
*Description of change*
*PTRs implemented in the new build*
***Test Directive (TD) specifically calls out regression testing to be performed on load to fully test change on spacecraft***

## Quality Assurance Spacecraft Bus Elements

***Quality Assurance Spacecraft Bus Elements***

***Overall Mission QA Requirements ***
***NMP/EO-1 Mission Assurance Requirements (MAR)***
***Spacecraft Bus QA Requirements covered in:***
***SAI-QA-008, EO-1 Performance Assurance Requirements for Spacecraft Bus***
*Appendix A of SAI-QA-008 covers EO-1 EEE Parts Implementation Plan & Procedure.  Plan conforms to the EEE parts requirements of GSFC 311-INST-001 for Grade 3 quality level parts.  The plan is similar & based on the MIDEX EEE parts requirements.*
***Subcontractor/Vendor QA requirements are dictated in existing company documentation unless specifically addressed in EO-1 Specification/SOW***
***I&T Work Order Authorization & Problem Report System process covered in SAI-PLAN-130, the EO-1 I&T plan***
***SAI-SPEC-158 EO-1 Verification Plan & Environmental Specification***
***Covers Verification Process and design/test environments***

## Quality Assurance Spacecraft Bus ElementsWorkmanship Standards

***Quality Assurance Spacecraft Bus Elements****Workmanship Standards*

***The following commercial, or NASA, workmanship standards are used for the EO-1 effort:***
***NHB 5300.4 (3M)******	******	******	******Workmanship standard for surface ******	******	******	******	******	******mount technology***
***NHB 5300.4 (3A-2) or ******	******	******	******Soldering of electrical connections ANSI/J-STD-001 thru 006 (Hi Rel)***
***NAS 5300.4(3G-1)******	******	******	******Cable, harness, & wiring ******	******	******	******	******	******	******interconnections******	***
***NHB 5300.4(3H)******	******	******	******Crimping***
***NAS 5300.4(3J)******	******	******	******Conformal coating and staking***
***IPC-D-275 [NASA alt.- NHB 5300.4(3K)]******	******	******Printed wiring board design***
***EIA-625 [NASA alt.-. NHB 5300.4 (3L)]******	******	******ESD control***
***Technicians required to be certified for the specific standard***
***Printed wiring board coupons evaluated at GSFC or by a GSFC approved laboratory.  Approval required prior to population of printed wiring board.***

## Quality Assurance Spacecraft Bus ElementsWork Order Authorization (WOA) System

***Quality Assurance Spacecraft Bus Elements****Work Order Authorization (WOA) System*

***The WOA System controls all work performed on the spacecraft***
***Initiated by Subsystem Lead or Test Conductor, and only authorized after the following actions:***
***Referenced Procedure released through CM***
***Signature of Systems Mgr., Subsystem Lead, Mech. & Elec. Leads, I&T Mgr & QA Mgr.***
***Following successful completion of work, WOA will be closed after approval from I&T Manager & QA***
***If a Problem Report is issued, the WOA remains open until PR is disposition & closed ***
***Original WOA with supporting information will then be entered into S/C logbook***
***WOA System uses an ACCESS 97 database developed specifically for EO-1***
***Provides statistics on WOAs and Problem Records, ***
***GSFC representative has full access to database at anytime & is invited to attend all meetings***
***Database is located on I&T network which will be portable to the Launch Site ***

## Quality Assurance Spacecraft Bus ElementsWork Order Authorization (WOA) System

***Quality Assurance Spacecraft Bus Elements****Work Order Authorization (WOA) System*

## Quality Assurance Spacecraft Bus ElementsProblem Records (PRs) and S/W Problem Test Reports (PTRs)

***Quality Assurance Spacecraft Bus Elements****Problem Records (PRs) and S/W Problem Test Reports (PTRs)*

***PRs are anomalous events that are inconsistent with expected results***
***PRs entered into the ACCESS database system & assigned numbers associated with the WOA under which the work was performed***
***PRs are entered into the database system as they occur***
***PRs must be dispositioned, corrective action taken and closed before WOAs can be closed***
***Closure of PRs requires approval from responsible subsystem lead & QA***
***PR meeting held typically every two weeks or as required to review status & develop corrective action plan ***
***QA responsible to follow through with Subsystem Leads on closure***
***PTRs are analogous to PRs in Software environment. ***
***PTR data base maintained by Hammers Co.***
***FSW-related PRs generated during S/C I&T have an associated PTR ***
***FSW PR closure requires closure of the associated PTR***
***PTRs also are generated during FSW testing in software lab & MAP program***

## Quality Assurance Spacecraft Bus ElementsPR Closure Process

***Quality Assurance Spacecraft Bus Elements****PR Closure Process*

***Typical PR Meetings held with the following Representatives:***
***Responsible Subsystem Engineer  (PR Assignee)***
***System Engineering***
***Swales Quality Lead***
***GSFC Quality Assurance Manager***
***Swales Program Manager***
***GSFC Mission Manager and or Observatory Manager***
***PR Closure requires agreement of all of the above***
***The PAR form used during spacecraft I&T replaces the Material Review Board Report form used during hardware development as referenced in the CERT Log***

## Quality Assurance Spacecraft Bus ElementsWOA Status

***Quality Assurance Spacecraft Bus Elements****WOA Status*

***Spacecraft I&T WOA Statistics ***
***Total number generated as 3/24/98 through 3/21/00 = 952***
*Note all work prior to 3/24/98 is covered in component/subsystem certlogs*
***Number Closed out =  924 (97% closure rate)***
***Open Work Orders = 28 (as of 3/21/00)***
*Work In Process**	**	**= 8*
*Open PRs**	**	**= 16 (two on WOA-829)*
*Close Out Work**	**	**= 3*
*In Close Out Process **	**= 0*

## Quality Assurance Spacecraft Bus ElementsProblem Report Status

***Quality Assurance Spacecraft Bus Elements****Problem Report Status*

***Total number generated from 4/1/98 through 3/21/00 =  1572***
***Number Closed out  =  1554 (98.9% closure rate)***
***Number open  =  17 (as of 3/21/00)***
***Work In Process******	******	******= 9***
***Test verification required ******	******= 0***
***In Closure Process******	******	******= 5 ******(one potential Redbook candidate)***
***Redbook Items ******	******	******= 3***
*WOA 468-20-4 IRU Helium Exposure (see Special Topic)*
*WOA 770-20-3 One Time Event Chassis Current during EMC Testing (see Electrical Systems)*
*WOA 837-20-1 One Time Event LVPC Current Red Limit (see Power Subsystem)*

## Quality Assurance Spacecraft Bus ElementsCritical  Problem Reports

***Quality Assurance Spacecraft Bus Elements****Critical  Problem Reports*

***In response to Pre-Ship Review Teams request the EO-1 Project Team has identified all Problems Reports that were generated from the start of Thermal Vacuum (10/1/99) that fall in the following categories:***
***Flight Hardware Changes***
***Flight Software Changes***
***“******Use As Is” Classification/MOC Constraint Manual***
***Redbook items / unknown***
***Under investigation (as of 3/21/00)***
***All Problem Reports that are classified as critical, or that remain open as of 3/21/00, are addressed within the Subsystem presentations or in the Special Topic sections ***
***Residual Risk has been assessed for all critical and open PRs***
***All open Problem Reports prior to the 10/1/99 were addressed in detail at the Thermal Vacuum readiness reviews (9/24/99, 10/1/99)***

## Quality Assurance Spacecraft Bus Elements

***Open Problem Reports***

**Pre TV**

## Quality Assurance Spacecraft Bus ElementsSummary of Critical PRs as of 3/21/00

***Quality Assurance Spacecraft Bus Elements****Summary of Critical PRs as of 3/21/00*

***122 Critical Problem Reports, all closed with exception of 4***
***7 Hardware ***
*Re-wire thermostats and heaters on nadir deck (3) (Special Topic)*
*Rework LFSA power and telemetry interface (Special Topic)*
*Reset ALI HOP*
*Repair WARP 5-volt power service*
*Battery Trickle Charge Fuse (ground use only)*
***78 Software (see S/W presentation)***
*Expected because of limited testing available in the S/W lab without ETUs*
*Many related to improved deployment logic (20) and failure monitoring implemented in the TSM system (20)*
***33 “Use as is” / constraint manual***
*May add complication during operations, but not residual risk*
***2 (Post 10/1/99) Redbook items***
***2 under investigation (WOA-949, WOA-943)***
***Negligible residual risk due to the critical PRs***

## Spacecraft Problem Report Statistics from 10/1/99 to 3/20/00

## RFA #2.06 Delta Confirmation Review (RFA #6) 

***RFA #2.06 ******Delta Confirmation Review (RFA #6) ***

***Define which spacecraft-level test will not be conducted with both flight instruments installed and the rationale and how the instruments will be tested to assure mission success (safe launch and successful on-orbit performance)***
***This RFA has been since overtaken by events since all the instruments were available for the start of the environmental test program. Therefore, there was no need to justify a separate spacecraft-level test program***

## Critical PRs not covered in other Sections

***Critical PRs not covered in other Sections***

## Integration & Testing Staff

## Integration & Testing Staff

## Integration & Testing Staff

## Integration & Testing Staff

## Integration & Testing Staff

## Additional Systems Information

***Section 13a***

*** ******. . . Mark Perry***
*Swales Aerospace, Inc.*

## EO-1 Mission and Subsystem Modes

**Switch to Internal Power**

**Separation from L/V**

- *   Turned ON during early Mission Ops
- **  Includes 30 W of survival heater power

***EO-1 Mission and Subsystem Modes***

## EO-1 Changes Since Environmental Test

***EO-1 Changes Since Environmental Test***

***LVPC fuses on non-critical services: full environmental testing***
***S/A release HOP fuses: environmental and functional testing***
***New s/w: all verified by extensive regression testing***
***M5***
*ACS: arctan, warm start time, validate GPS data using HK RSN flag*
*Time code: add GPS leap second*
*XB: 1773 request 2 words to prevent hangup*
*TSMs and RTSs: table loads*
*TO: jam limit on APIDs, filter tables, add GPS leap second*
***Read/write timing for all RSNs A/D conversion (except WARP RSN)***
***HK RSN: GPS, time processing, and deployment (auto-detect)***
***ACE: SHM inhibit, IRU event message, checksum***
***PSE and COMM: no change other than A/D read***
***X-band: open telemetry limits on FDC***

## EO-1 Changes Since Environmental Test (continued)

***EO-1 Changes Since Environmental Test ****(continued)*

***Nadir-deck heaters re-wired; bay-5 heater on new service; fully tested***
***WARP removed, repaired, tested, and re-integrated for TV test***
***ACDS removed, opened, x-rayed, workmanship vibe, and re-integrated***
***LFSA: power re-work, re-integrated with full functional test***
***AST removed, and filter replaced, workmanship vibe, and re-integrated***
***Replace trickle-charge fuse with diode: non-flight path***
***IRU removed (from Helium exposure), 5 of 6 vent holes closed, re-integrated***
***Hyperion electronics removed for access to panel: re-integrated***

## Redundancy on EO-1

***Redundancy on EO-1***

***1773 communications bus***
***MV memory and processes area (2 PROMs and areas of RAM)***
***Special hardware command path for contingency commands***
***Thermal control system: power services, heaters, and t-stats***
***S/A release: power, HOPs, switches, activation, mechanisms***
***Backup to GPS: time and position are up-loadable***
***Independent processor for safehold attitude***
***Dual coils on magnetic torquer bars***
***RCS thruster valves and valve seats***
***S/A drive: drive motors, drive electronics, and position indicators***
***Battery temperature monitor***
***S-band backup for science downlink***
***TDRSS telemetry and commanding***
***SSPC Power harnesses, S/A and battery wiring, BERB relays***
***ALI thermal control system***
***Backup device for opening ALI door***

**13 - **

## Built-In Redundancy that Contributes to Graceful Degradation

***Built-In Redundancy that Contributes to Graceful Degradation***

***Multiple S/A strings***
***4 GPS antennas***
***2 S-band antennas, on opposite decks***
***64 amplifiers in X-band phased array***
***22 battery cells and large capacity permits functionality after some failure modes***
***Two WARP memory boards, each with multiple blocks***
***Coupled thermal control***

## EO-1 S/C Risk Management Process - 1

***EO-1 S/C Risk Management Process - 1***

***Mostly informal: process not well documented, ***
***Implementation is formal: PRs, PTRs, reviews, etc.***
***Elements of risk management***
***Top-level requirements and ICDs***
*Active management of ICDs, looking for problems*
***Constant communication between subsystems***
*Weekly, full-team, technical review meetings*
*Monitor cost and schedule as additional problem indicators*
***Emphasis on design margins and approved parts***
*Increases reliability in single-fault areas*
***Internal review and peer reviews***
*Resulted in changes and risk mitigation*
*Insert redundancy where mitigated risk warranted extra cost and complexity*
*Review requirements during development; de-scope if necessary*
*Sacrifice performance rather than increase cost or risk*

## EO-1 S/C Risk Management Process - 2

***EO-1 S/C Risk Management Process - 2***

***Elements of risk management (continued)***
***Examples of changes due to technical reviews***
*ACE safehold on independent processor*
*PSE H/W and S/W: analysis and changes*
*Extra ACS phasing tests*
*X-band near-field test*
*Fuse plugs*
*Second TV test*
***Active investigation and implementation of other-mission issues***
*IMAGE (PSE, DC/DC converters, etc), MAP (Flight S/W, AST, HSSR 7111 oscillations, etc.), TIMED (S/A cell de-bonding)*
*Continued communication with the related missions*
***Comprehensive, rigorous, integration and system test***
*No sacrifices in documenting integration procedures*
*Identifies risks*
*Mitigates risks incurred during rapid development*
***Strict and thorough attention to PRs during I&T***
***Take advantage of delays to further retire risk***
*Additional testing, including contingency and simulation testing*

## Top Risks and Mitigation on EO-1

***Top Risks and Mitigation on EO-1***

***Single string failure possibility: LVPCs, MV processor, COMM RSN, transponder, ACS components, PSE RSN: mitigate by continued improvement of contingency procedures and continued review of parts vulnerability***
***WARP recovery: mitigation is full environmental testing at box level, TV at S/C level***
***Flight software: mitigation is 2 additional CPTs, 2nd TV, and ops sims***
***IRU sensitivity to helium: removed from S/C, purge until launch, close extra vent holes, improve purge lines***
***AST quality: mitigation is complete (extra testing and parts review)***
***SSPC fuses trip at too high current; possible problem if 1.5 to 2 ohm short: mitigated by TSMs and FDC***
***A/D anomalies: testing on MAP ETU to investigate cause***