Transcript Document

Systems Engineering
Mike Pryzby
Swales Aerospace
August 16-17, 2005
NASA’s Goddard Space Flight Center
05 - 1
LRO Systems Team
Martin Houghton
Mission Systems Engineer
Mission Requirements Document (MRD)
Systems Concept
Requirements Management
T. Ajluni
J. Brannen
Tom Jones
Launch Vehicle Manager
LV ICD
Mike Xapsos
Radiation
Engineer
Radiation Environment
Assessment
Chris Lorentson
Contamination
Engineer
Contamination Control
Plan
Rich Saylor
Ground Systems
Concept of
Operations
Joanne Baker
I&T Engineer
I&T Plan
Arlin Bartels
Payload Systems Manager
Michael Pryzby
Orbiter Systems Engineer
J. Baker
L.Hartz
M. Reden
Phil Luers
Electrical Systems
Electrical Sys. Spec
Electrical ICDs
Giulio Rosanova
Mechanical
Systems
Mechanisms
Deployment Sys
Mechanical ICDs
Eric Holmes
GN&C Systems
GN&C Architecture
R. Kinder
Nick Virmani
Mfgr Engineer
Parts Review
Parts Use / Applicability
Database
Lydia Lee
Systems Reliability
Engineer
Reliability Analysis
(FTA,FMEA, RBD, etc.)
Pilar Joy
Materials Engineer
Ken Deily
Mission Success
Systems Engineer
Material Review
Materials Use /
Applicability Database
Subsystem
Leads
Charles
Wilderman
HW / SW Systems
Software Architecture
S/W Resources
Software ICDs
Level 3 Requirements
Subsystem Spec & Verification Plans
Component Specs
ICDs
J. Simpson - ACS
R. Saylor - Ground System
Q. Nguyen - C&DH
C. Baker - Thermal
C. Zakrzwski - Prop
R. Kinder - Harness
J. Soloff - Comm.
M. Hersh - Mechanisms
M. Blau - Flight S/W
G. Casto - Structures
T. Spitzer - Power
NASA’s Goddard Space Flight Center
M. Beckman - Flight Dynamics
05 - 2
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
The Three Major Functions Must Lead to a Balanced Design that is
Consistent with Project Cost, Schedule and Risk
Architecture & Design
Requirements ID & Mgmt
- Level 1 Reqs, Min Mission Reqs
-Mostly Driven by Science
- Top Down Hierarchy
- Reqs Flow, Doc Tree, WBS,
Product Structure, Team Org
-Database utilized to track reqs flow,
owner, verification
- What the End Item looks like
- Flight and Ground Elements,
Hardware, Software Block
Diagrams, Operations Team
-Special Accommodations for
Verification & Test
- Design for testability
Project Objectives Met,
Ready for Operations
Operations Concept Development
- How the End Item is used
-Flight and Ground Elements, Hardware, Software,
Operations Team
- How the End Item can be verified & tested on the ground
- Test Points, GSE impacts on Architecture and Design
- 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
NASA’s Goddard Space Flight Center
05 - 3
Phase A Plans and Activities
LRO SEMP (431-PLAN-000005) System Engineering Lifecycle Activities Matrix
All Completed 
Preliminary Analysis - Phase A
Understanding the
Objectives
Operations Concept
Development
Architecture & Design
Development
Requirements
Identification &
Management
Validation &
Verification
Interfaces & ICDs
Mission Environments
- 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
- Identify and define LRO Mission Phases
- Complete preliminary draft version of LRO Operation Concept Document
- 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
- 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
- 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
- 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
- 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
Configuration
Management &
Documentation
System Engineering
Management Plan
- 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
- Define LRO document tree and define subject, when due, and who responsible for each document
- 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”
NASA’s Goddard Space Flight Center
05 - 4
Phase B Plans and Activities
LRO SEMP (431-PLAN-000005) System Engineering Lifecycle Activities Matrix
Black –done, ◘Green – In progress
System Definition - Phase B
Understanding the
Objectives
Operations Concept
Development 
Architecture & Design
Development ◘
- 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
- 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 ◘
System Milestone
Reviews ◘
Configuration
Management &
Documentation
System Engineering
Management Plan ◘
- 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
- 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
- Initiate CCB process to address changes to configured documents
- Bring Level 1 Reqs, MRD Level 2 Reqs, and Level 3 Subsystem spec under CM
- Update SEMP for Phase C Design activity plans to ensure system is “implemented right”
NASA’s Goddard Space Flight Center
05 - 5
Requirement Capture and Control
Process
L1 Requirements
Controlled at NASA HQ
L2 Requirements
Controlled at LRO Project
L3 Requirements for
Spacecraft, Ground Elements
Controlled at LRO Project
LRO Project Level
Tracking Verification Database
In DOORS
L3 Requirements
for Instruments
Controlled at PI Institution
L4, L5, L6 Requirements
Developer Controlled at LRO or PI Institution as Rqd
NASA’s Goddard Space Flight Center
Updated
Documents in
CM*
*CM Plan is Document
431-PLAN-0000xx
05 - 6
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)
???
TOPIC
Spacecraft &
Ground
DATE/TIMEFRAME
System Phase
Phase
Subsystem Peer Reviews
A/B
C/D
S/C Mechanical Sy stems
8/5/05
9/21/05
Thermal Sy stem
9/15/05
GN&C
8/5/05
9/15/05
Propulsion Module
5/5/05
3/22/06
Propulsion Tank
3/10/06
Pow er
8/5/05
9/13/05
C&DH
9/5/05
9/22/05
FLT S/W
11/5/05
11/4/05
Communication
Ground netw orks
Ground Data Sy stem/MOC
Instrument Peer Reviews
Div iner
8/25/05
LROC
8/1/05
LOLA
CRaTER
LAMP
6/17/05
LEND
Focused Technical Peer Reviews
PDE detail design options and
38569
reliability assessment
FPGA Implementations (all
A/R
A/R
38600
N/A
38569
N/A
subsy stems using FPGAs)
SSR implementation options
preliminary design decision rev iew &
assessment. (C&DH, Flight Softw are)
High Accuracy Tracking
implementation options and decision
rev iew . (Comm., GDS, LOLA)
NASA’s Goddard Space Flight Center
05 - 7
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.
NASA’s Goddard Space Flight Center
05 - 8
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.
•
•
•
–
Level 2
Req.
Mission
Success
Criteria
Level 3
Req.
Advanced
Functional
Schematics
(concept)
Degraded
Mission
Criteria
……
Advanced
Functional
Schematics
(concept)
Mission Success vs. Implementation
Decisions
•
•
•
•
Criticality & Degraded Mode Analyses
Critical Items List, FMEAs, RBDs,
FTAs, & PRA
Safety & Reliability Analyses
Safety
Req.
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
NASA’s Goddard Space Flight Center
Identify Mission
Success &
Degraded
Mission
Performance
Risks
Trades
Req.
Chg
Identify Mission
Success &
Degraded
Mission
Performance
Risks
Trades
Req.
Chg
05 - 9
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
NASA’s Goddard Space Flight Center
LRO - PSE Reliability Prediction Worksheet
Output Module A
D esig nat o r
Par t D escr ip t io n & T yp e
Par t N umb er
LRO SPACECRAFT RELIABILITY BLOCK DIAGRAM
M anuf act ur er
Quant it y
C r it ical
QualitBy ase F ailur e
T o t al
C3, C5, C7, C10, C700,
C1000, C4, C6, C8,
C12, C13, C23, C34,
C35, C43, C51, C53,
C54, C55, C56, C14,
C15, C16, C17, C18,
C19, C20, C21, C22,
Cap, Ceramic, Chip, 0.010 uF, 25V,
C24, C25, C26, C27,
C28, C29, C30, C31,
C32, C33, C62, C63,
C64, C65, C66, C67,
C68, C69, C70, C71,
C72, C73, C74
npC37, C38
T o t al F ailur e
% o f A ssemb ly
Reliability
Allocation
U sed
Including 1 Instrument
F R xN 1xQ F R xN 2 xQ
LRO SPACECRAFT RELIABILITY BLOCK DIAGRAM
Presidio
Components
SR0805X7R103
56
60
1 6.3400E-13
Obtained
FR from the
LRO
Spacecraft
3.5504E-11 3.8040E-11 # # # # # # # # # #
Presidio
Components
LRO SPACECRAFT RELIABILITY BLOCK DIAGRAM
Cap, Ceramic, Chip, 10 uF, 50V, 10%
SR0405BX106K2S2
Cap, Ceramic, Chip, 0.10 uF, 50V, 10%
SR0805X7R104
C59
Cap., Fixed, Tantalum, Solid, ER, 22 uF, 20V, 10%
C82
C83
C200, C201, C202,
C204, C205, C206,
C208, C209, C210,
C212, C213, C214,
C220, C221, C222,
C224, C225, C226,
C228, C229, C230,
C232, C233, C234,
C236, C237, C238,
C240, C241, C242,
C244, C245, C246,
C248, C249, C250,
C252, C253, C254
C203, C207, C211
C215, C223, C227,
C231, C235, C239,
C243, C247, C251,
C255
C216, C217, C218,
C219
M anufacturer.
Reliability Allocation
R = 0.90
Including 6 Instruments
C44, C45, C46, C47,
C48, C49, C52, C50,
C84
C81
N o t es
R at e ( F R )C r it ical C ktB eing U sedC r it . C kt B eing
C kt ( N 1)
U sed ( N 2 ) ( Q)
Presidio
ReliabilityComponents
Allocation
2
2
9
GN&C
9 Power
1 6.3400E-13 5.7060E-12
1 6.3400E-13 1.2680E-12
1.2680E-12 # # # # # 0.0001%
Obtained FR from the
M anufacturer.
Obtained FR from the
Communications
5.7060E-12C&DH
# # # # # # # # # # Propulsion
M anufacturer.
Deployment
Instrument
R = 0.98506
R = 0.98506
LRO Spacecraft
CWR06JC226KCA
1
1
0.01 7.0000E-10 7.0000E-12 7.0000E-12 0.0010% 0.0007% Grade-1
R = 0.98506
Cap., Fixed, Tantalum, Solid, Low ESR, 100 uF, 16V, T495X107K016AS
10%
(562)
M 123A02BXB105K
Cap., Fixed, Cer. Dielectric, 1.0 UF, 50V, 10%
C
Cap., Fixed, Tantalum, Solid, Low ESR, 220 uF,
T495X227K006AS
6.3V, 10%
(562)
1
1
1
1
1
1
27
39
0.03 7.0000E-10
R = 0.98506
2.1000E-11
R = 0.98506
R = 0.98506
2.1000E-11 #R# #
# #####
=#0.90
Commercial. Goddard
screening to FR Level: S
R = 0.98506
0.1 8.6000E-10 8.6000E-11 8.6000E-11 0.0117% # # # # # Grade-2, FR Level: C
0.03 7.0000E-10
2.1000E-11
2.1000E-11 # # # # # # # # # #
Commercial. Goddard
screening to FR Level: S
LRO Spacecraft
R = 0.90
Cap, M ulti Layer, Fixed, Unencap, Ceramic
Dielectric, 0.1 uF, 100V, 10%
Power
GN&C
Cap, Tantalum, Non-Solid, 6.8 uF, 75V, 10%
R = 0.98529
R = 0.98529
Cap, Tantalum, Non-Solid, 3.3 uF, 75V, 10%
Cap, Tantalum, Non-Solid, 110 uF, 75V,
CDR35BX104BKUS
Power
GN&C
R = 0.99126
C&DH
Propulsion
M 39006/30-0826
R = 0.98529
R = 0.98529
M 39006/30-0823
93026-46KS
Communications
3
3
R = 0.98529
6
10
4
4
C&DH
Propulsion
Communications
Deployment
Instrument
R = 0.99126
R = 0.99126
0.03 1.8000E-09 1.4580E-09 2.1060E-09 0.1980% # # # # # Grade-1, FR Level: S
R = 0.99126
R = 0.99126
R = 0.99126
R = 0.99126
Deployment
0.3 1.1000E-09 9.9000E-10 9.9000E-10 0.1344% 0.1035% Grade-2, FR Level: P
R = 0.98529
0.3 1.1000E-09 1.9800E-09 # # # # # # #
#####
0.3451% Grade-2, FR Level: P
0.1 1.1000E-09 4.4000E-10 4.4000E-10 0.0597% # # # # #
Commercial. Goddard
screening to FR Level: R
05 - 10
Driving System Trades
TOPIC
LV
Prop
Primary Structure
Solar Array Configuration
Data Bus Architecture
Data Storage
Timing
Tracking
Comm System
NASA’s Goddard Space Flight Center
TRADE
2 Stage vs 3 Stage
Mono Prop vs Bi Prop vs Hybrid
OUTCOME
7925H-9.5 ELV
Mono Prop
Honeycomb with Al
facesheets for bus,
composite face sheets for
Material, configuration and tank
instrument deck,
accomodation
Configuration J
Single circular Ultra Flex
Structure, shape and materials
array
1553 for low speed,
Spacewire for high speed
1553, SpaceWire, CAN, Wireless, etc. interfaces
SRR or Hard Drive
Ongoing, due at PDR
USO in bus or LOLA instrument
USO part of bus C&DH
S Band vs Other
Ongoing, due at PDR
Ka vs X-Band
Ka
05 - 11