Systems Engineering

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Systems Engineering Goddard's GPR Guideline,
Mission Concept Studies, and Support Tools
John Azzolini Systems Engineering Services and
Advanced Concepts Branch September 2005
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Agenda

• A Brief Overview Of GPR 7120.5A Concepts
• An Examination Of The Pre-phase A Concept Study
  To Illustrate The Guidelines
• A Demonstration Of A Systems Engineering
  Validation Support Tool

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Overview of GPR 7120.5A

• What is the GPR?
• A practical definition of what should be done as
  a part of good systems engineering practice
• Based on the NASA Systems Engineering Handbook
  SP-6105
• Incorporates principles of industry systems
  engineering standards
• Why do we have it?
• Correct deficiencies in the execution of systems
  engineering. (Many of the root causes of
  Aerospace Industry failures were traced to poor
  systems engineering)
• Describe what constitutes good systems
  engineering
• Improve uniformity of systems engineering in
  completeness and quality
• How can it be useful?
• Serves as a set of reminders for what should be
  considered
• Provides guidance for establishing a project
  unique systems engineering plan
• Provide common understanding and expectations
  within the Goddard systems engineering community

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Overview of GPR 7120.5A

• Principles
• Encourage a Team Approach
• Cover full mission life-cycle
• Define the whats
• Show product maturity over life-cycle
• Stress Validation
• Keep good practices of the past

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Overview of GPR 7120.5A

• Document Contents
• Preface Purpose, Applicability, Authority,
  References, Cancellation, Safety, Training,
  Records, Metrics, Definitions
• Roles and Responsibilities
• Communications
• Key Systems Engineering Functions
• Configuration Management and Documentation
• Systems Engineering Management Plan
• App A - Systems Engineering Requirements
• App B - System Engineering Management Plan
  Outline
• App C - Tailoring Guidelines

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Overview of GPR 7120.5A

• Roles And Responsibilities
• Project or study manager teams with Mission
  Systems Engineer
• Mission Systems Engineer coordinates and
  facilitates team
• SEMP describes details

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Overview of GPR 7120.5A
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Overview of GPR 7120.5A

• Communications
• Systems Engineering is a Team Activity
• The Mission System Engineer facilitates and
  coordinates team effort
• Solutions converge when decisions are made
• Validation is the job of all team members

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Overview of GPR 7120.5A
The organization of information, to understand
our goals,

• Key Systems Engineering Functions
• Understanding the Objectives
• Operations Concept Development
• Architecture and Design Development
• Requirements Identification and Management
• Validation and Verification
• Interfaces and ICDs
• Mission Environments
• Technical Resource Budget Tracking
• Risk Management
• System Milestone Reviews

and to systematically achieve them .
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Overview of GPR 7120.5A
Maintaining information which accurately reflects
our decisions

• Configuration Management and Documentation
• Identify information products which must be
  configured
• Use project CM system to maintain
• Single point of configuration
• Change control at the appropriate time

to assure integrated success .
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Overview of GPR 7120.5A
Plans are nothing -

• Systems Engineering Management Plan
• What, who, when, where, how
• An active plan, it is updated and used to plan
  efforts
• Products defined
• Tasks defined
• Schedule maintained
• Costs maintained

planning is everything Dwight Eisenhower.
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Mission Concept Study

• Back to the SE functions
• Understanding the Objectives
• Operations Concept Development
• Architecture and Design Development
• Requirements Identification and Management
• Validation and Verification
• Interfaces and ICDs
• Mission Environments
• Technical Resource Budget Tracking
• Risk Management
• System Milestone Reviews
• What is known? What needs to be known?
• Lets start at the very beginning

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Mission Concept Study
All the worst mistakes

• Mission Objectives
• Mission Needs is a better term

are made the first day Anon.
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Mission Concept Study
Mission Needs for Other NASA Mission Types
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Mission Concept Study
Design Specification and Validation Flows
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Mission Concept Study
Mission Design

• Payload Concept

depends on payload design.
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Mission Concept Study
Partitioning of functionality

• Mission Design

between space and ground is made here.
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Mission Concept Study
And now

• System Design

Instrument Accommodation Requirements
Mission System Requirements
Spacecraft Design Ground System Design Launch
Accommodations
Mission Architecture
Mission Operations Concept
system design can proceed.
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Mission Concept Study
A continuing validation of products
Verification and Validation

• Validation -
• Assuring that the design is correct (Did we
  build the right system?)
• Validation of mission needs flow-down (flow of
  authority) (necessary)
• Validation of design compliance to needs
  (sufficient)
• Functionality
• Performance Analysis
• Verification -
• Assuring that the implementation is correct (Did
  we build the system right?)
• Testing, analysis, and inspection
• Verification of function and performance
• Verification of implementation
• Verification of operations
• Note Many people (erroneously, in my opinion)
  call end-item operational verification
  Validation Pshaw!

keeps the team coordinated.
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Mission Concept Study
Putting it all together
Mission Needs
Mission Design
System Design
for a complete validation of design.
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Mission Concept Study
Good interface requirements and interface
control documents
Interface Requirements and ICDs
Interface Requirements Functional Performance Stan
dards Compliance Interface Control
Documents Function Form Specifications
Properties Covered Mechanical Electrical Thermal P
ower Ground
allow decoupling of implementation efforts.
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Mission Concept Study
Determine mission environments early
Mission Environments

• Launch Environment
• GEVS
• Mechanical Sine, Sine Sweep, Acoustic
• Electrical - EMI, EMC
• Shock
• External RF

• External Space Environment
• Atomic Oxygen
• Radiation TID
• Radiation SEE
• Thermal Cycling
• Power Cycling
• Internal Environment
• Grounding
• Noise
• Power Surges

and apply uniformly.
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Mission Concept Study
Everything depends on

• Mission Technical Resources
• Mass Affects launch margin, ACS, propellant
• Power Affects mass, thermal dissipation
• Thermal Affects Alignment, Life, calibration
• Attitude Affects measurement resolution, image
  smearing
• Position Affects orbit dependent aspect
  knowledge
• Data Affects bandwidth, link margin, storage
• RF Affects power, mass
• Essentially all the things where margins are
  defined

everything old systems engineering adage.
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Mission Concept Study
Mission risks

• Mission Risks
• Safety Risks
• Hazard analyses are the prime method to identify
  safety risks
• Project management should understand and manage
  safety risks
• Performance Risks
• FMEA, FTA, RBD and PRA are good tools here
• Sound design practices, simple robust designs,
  and adequate peer review
• High to low risks often on a logarithmic scale
• Project management should understand and manage
  performance risks
• Programmatic Risks
• Schedule, Cost
• Classical FMEA, FTA, RBD do not apply here,
• Communication and continuous assessment of
  progress
• High to low risks often on a linear scale
• Element lead and/or project management has
  responsibility for managing programmatic risks

are of three distinct types.
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Mission Concept Study

• Product Maturity and Reviews

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A Systems EngineeringValidation Support Tool
Caveat A fool with a tool is still a fool
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In closing
. . . Come my friends, tis not too late to seek
a newer world.Push off, and sitting well in
order smitethe surrounding furrows for my
purpose holdsto sail beyond the sunset, and the
bathsof all the western stars, until I die. -
A. Lord Tennyson, Ulysses