1. Aerospace Systems Engineering
Chapter 1- Overview of the Engineering of Systems By
Dr. Sartuk KARASOY
Middle East Technical University
The viewgraphs are mainly courtesy of Dr. Dennis Buede.
Chapter 1- Overview of the Engineering of Systems

2. Engineering of Systems
Broad perspective, not deep
What must be done, how well it must be done, how it should be tested before what it is
Clear focus on system's objectives
Design: start with supersystem, migrate towards subsystems and components
Integration: start with pieces and build to system in its real environment
Chapter 1- Overview of the Engineering of Systems

3. Chapter 1- Overview of the Engineering of Systems
System Life Cycle
Concept
Definition
Identification
of Need
Refinement
Preliminary
System Design
Detailed
Configuration
Item Design
System
Integration
Production &
Manufacturing
Deployment
Operation
Retirement/Disposal
Maintenance
Time
Training
Chapter 1- Overview of the Engineering of Systems
Figure 1.1

4. Reason Why Engineering a System Needs To Be Done Well Early
Cost
Time
100%
80%
60%
40%
20% 0%
Conceptual
& Preliminary
Design
Detailed
Design &
Integration
Construction or
Production
Use,
Refinement
& Disposal
Cost Committed
Cost Incurred
Reason Why Engineering a System Needs To Be Done Well Early
Chapter 1- Overview of the Engineering of Systems
Figure 1.2

5. Chapter 1- Overview of the Engineering of Systems
Definitions
Engineering: discipline for transforming scientific concepts into cost-effective products through the use of analysis and judgment
Engineering of a System: engineering discipline that develops, matches, and trades off requirements, functions, and alternate system resources to achieve a cost-effective, life-cycle balanced product based upon the needs of the stakeholders
Chapter 1- Overview of the Engineering of Systems

6. Vee Model of Design and Integration
Understand User
Requirements, Develop
System Concept and
Validation Plan
Develop System
Performance Specification
and System
Expand Performance
Specifications into CI
“Design-to” Specifications
and CI Verification Plan
Evolve “Design-to”
Specifications into
“Build-to” Documentation
and Inspection Plan
Fab, Assemble and
Code to “Build-to”
Documentation
Inspect
“Build-to”
Assemble CIs and
Perform CI Verification
to CI “Design-to”
Specifications
Integrate System and
Perform System
Verification to
Performance Specifications
Demonstrate and
Validate System to
User Validation Plan
Decomposition
Definition
and
Integration
Qualification
Design
Engineering
Systems Engineering
Time
Chapter 1- Overview of the Engineering of Systems
Figure 1.3

7. Vee Model with Onion Peels
Understand User
Requirements, Develop
System Concept and
Validation Plan
Develop System
Performance Specification
and System
Expand Performance
Specifications into CI
“Design-to” Specifications
and CI Verification Plan
Evolve “Design-to”
Specifications into
“Build-to” Documentation
and Inspection Plan
Fab, Assemble and
Code to “Build-to”
Documentation
Inspect
“Build-to”
Assemble CIs and
Perform CI Verification
to CI “Design-to”
Specifications
Integrate System and
Perform System
Verification to
Performance Specifications
Demonstrate and
Validate System to
User Validation Plan
Decomposition
Definition
and
Integration
Qualification
Design
Engineering
Systems Engineering
Time
Peels of the Onion
Chapter 1- Overview of the Engineering of Systems

8. Race Car Example of Requirements and Tests
Operational Need or Mission Requirements - Partially Validated by Operational Test (Proven by Real-World Experience)
System Level Requirements - Verified by System-Level Tests
Component Level Requirements - Verified by Component-Level Tests
Win the Indianapolis 500
· Pretrial average speed of 215 mph
· Average speed in the 500 of 190 mph
· Top speed of X mph
·  · Acceleration in all directions, g-g space
· Average standard pit time of Y seconds
· Engine horsepower of x Btu
· Body’s drag coefficient of y
· Range per tank of gas of z miles
“g-g” Design Region for a Racecar
(from [Milliken and Milliken, 1995])
Chapter 1- Overview of the Engineering of Systems
Figure 1.4

9. Chapter 1- Overview of the Engineering of Systems
Table 1.3

10. Expertise Required on the Systems Engineering Team
Management SE
Process
Domain/
Stakeholders
Technology
(Engineering
Disciplines)
Modeling,
Simulation,
Analysis
Chapter 1- Overview of the Engineering of Systems
Figure 1.5

11. Chapter 1- Overview of the Engineering of Systems
Requirements
Software
Preliminary
Design
Detailed
Coding and
Debugging
Integration
and Testing
Operations and
Maintenance
Waterfall Model
Chapter 1- Overview of the Engineering of Systems
Figure 1.6

12. Evaluate Alternatives; Identify and Resolve Risks
Prototype
1st
3rd
Operational
Benchmarks
Models
Simulations
Risk Analysis
Evaluate Alternatives;
Identify and Resolve Risks
Progress
through phases
Cumulative Cost
Determine Objectives,
Alternatives, and
Constraints
Commitment
Partition
Review
Requirements
Plan
Development
Integration
and Test Plan
Plan Next
Phases
Concept
Software
Validation
Product
Design
Design Validation
and Verification
Detailed
Code
Unit Test
and Test
Acceptance
Test
Implementation
Develop and Verify
Next Level Product
Spiral
Model
Chapter 1- Overview of the Engineering of Systems
Figure 1.7

13. Designing for Concurrency & Risk Mitigation
Chapter 1- Overview of the Engineering of Systems

14. Vee: Evolutionary & Incremental Development
SE Models
Vee: Evolutionary & Incremental Development
Incremental Development: Single Delivery
Evolutionary Development
Incremental Development: Incremental Delivery
Chapter 1- Overview of the Engineering of Systems

15. Operational Architecture Interface Architecture
SE Architectures
Operational Concept
Functional
Architecture
Physical
Operational Architecture
Interface Architecture
Chapter 1- Overview of the Engineering of Systems
Figure 1.9 (modified)

16. Chapter 1- Overview of the Engineering of Systems
Sample Physical Architecture
F-22 Weapon System
Vehicle
Training
Support
Avionics
Systems
Utilities &
Subsystems
Cockpit
Management
System
Electronic
Warfare
Navigation,
Identification
Processing
Controls
&
Displays
Stores
Inertial
Reference
Radar
Chapter 1- Overview of the Engineering of Systems
Figure 1.10

17. Life-Cycle Physical Architecture
Design & Integration
System
XYZ Weapon System
Operational
Training
Retirement
Avionics
Systems
Utilities &
Subsystems
Cockpit
Vehicle
Management
Electronic
Warfare
Navigation,
Identification
Processing
Controls
&
Displays
Stores
Inertial
Reference
Radar
Manufacturing
Deployment
Refinement
Chapter 1- Overview of the Engineering of Systems
Figure 1.11

18. Another View of the Design Process
Chapter 1- Overview of the Engineering of Systems
Figure 1.12

19. Chapter 1- Overview of the Engineering of Systems
Typical
Requirements
Documents
Chapter 1- Overview of the Engineering of Systems
Table 1.4

20. Chapter 1- Overview of the Engineering of Systems
Comparison of the Relative Cost to Fix Software in Various Life Cycle Phases [from Davis]
Chapter 1- Overview of the Engineering of Systems
Table 1.5

21. Chapter 1- Overview of the Engineering of Systems
Development Period
Chapter 1- Overview of the Engineering of Systems
Figure 1.13

22. Period of Pre-Initial Operational Capability
Chapter 1- Overview of the Engineering of Systems
Figure 1.14

23. Period of Operational Use and Refinement
Chapter 1- Overview of the Engineering of Systems
Figure 1.15

24. Chapter 1- Overview of the Engineering of Systems
Retirement Period
Chapter 1- Overview of the Engineering of Systems
Figure 1.16

25. Cycle Model Chapter 1- Overview of the Engineering of Systems
Design and Integration Cycles
1. Core cycle: Realization of stakeholder needs, followed by requirements development, design, manufacturing and product delivery
2. Verification cycle: Analysis, simulation, prototyping, integration, and testing
Management Cycles
3. Technologies and external resources cycle: Insertion of the appropriate technologies and resources into the systems engineering process
4. Controlling cycle: Configuration management of the design process and multiple product releases and updates
5. Strategic check cycle: Management assessment and approval of product development
Chapter 1- Overview of the Engineering of Systems
Figure 1.17

26. Define the Design Problem
Develop
Functional
Architecture
Design
Physical
Operational
Obtain
Approval &
Document
Define the Design Problem
Five Major Functions
of Systems Engineering Design
Chapter 1- Overview of the Engineering of Systems
Figure 1.18

27. Chapter 1- Overview of the Engineering of Systems
Detailed Functions of Systems Engineering Design
Higher Level
Requirements &
Constraints from
Approved Baseline
Define the
problem, the
system/segment/CI
Boundary, & the
objectives
Develop the
Op’l Concept
for the Sys,Seg,CI
under analysis
required
behavior in
a functional
interaction
diagram
functional
performance
by quantitative
analysis
Allocate
requirements
to functions
Define
candidate
physical
solutions
Evaluate
& select
best based
upon objectives
& requirements
functions
to Seg/CIs
Develop
interfaces
between
Seg/CIs
Plan test
& integration
of Seg/CIs
Obtain
approval
of boundary,
objectives,
concept of ops,
requirements,
physical solution,
& test plan
Document
Seg/CI
design
as approved
baseline
for next
lowest level
yes no
Define the Design Problem
Develop Functional Architecture
Physical
Architecture
Develop Operational Architecture
Obtain Approval & Document
Chapter 1- Overview of the Engineering of Systems
Figure 1.19

28. Functions of the Systems Engineering Integration Process
Verification Requirements and
Constraints from Approved Baseline
Inspect and test
to verification
requirements to
prove readiness for
integration with
next assembly
CI to be
verified
Deficiencies
Integrate with
next CI and
repeat
verification
process
Correctable
Identify and
fix correctable
deficiencies
Document
uncorrectable
For uncorrectable
deficiencies, confirm
no impact to
integration and get
deviation approval
from buyer
Modify approved
technical baseline
to incorporate
deviation
Redesign
Yes No
Chapter 1- Overview of the Engineering of Systems
Figure 1.20