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• Requirement 18 (Section 3.2.4.1) “The Center Directors or designees shall establish and maintain a process, to include activities, requirements, guidelines and documentation, for designing product solution definitions within the applicable WBS Model that satisfy the

Design SolutionDefinition

derived technical requirements.”

Design Solution Definition Process4

Andrew Part I (31 Mar 09) I - 2Part I

Design Solution Definition Purpose

• The Design Solution Definition Process is used to translate the outputs of the Logical Decomposition Process into a design solution definition

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Figure 4.3-2 Example of a PBS

Design Solution Definition: the specification of a rocket, for example

Andrew Part I (31 Mar 09) I - 3Part I

Design Solution Importance

• Define solution space• Develop design alternatives• Trade studies to analyze

– Alternate Design– Cost, performance, schedule

• Select Design Solution• Drive down to lower level• Identify enabling products

Design with the end in mind!

What we wanted

What we got

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This image of a space shuttle has been removed due to copyright restrictions.

This image of a space shuttle in a building complex has been removed due to copyright restrictions.

Andrew Part I (31 Mar 09) I - 4Part I

Design Solution Questions

• What types of criteria are necessary to evaluate alternate design solutions?– Does it meet technical requirements?– Is it compatible with the other system components?– How difficult is it to produce?– Can it be delivered within acceptable time frame?– How reliable will it be?– Which functions does this solution satisfy?– How easy will it be to operate?

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Andrew Part I (31 Mar 09) I - 5Part I

Design Solution Definition

• As alternative concepts are considered, the Design Solution Definition Process includes:– Transforming the defined logical decomposition

models and their associated set of derived technical requirements into alternative solutions

– Fully defining the selected alternative(s) into a design solution definition that will satisfy the technical requirements

• This process is repeated at lower levels as additional subsystems need to be defined

3.2.4.2 – Design Solution Definition Purpose

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Andrew Part I (31 Mar 09) I - 6Part I

Design Solution Methods

• Group and Partition functions with system elementsPhysical

System Elements Functions

Vehicle Avionics Solar Array Fuel Cell Antenna

Launch X X

Guide X

Deploy X

Communicate X X

Power X X

Recover

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Andrew Part I (31 Mar 09) I - 7Part I

Trade Study Process 4

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Important Design Considerations

Capabilities

Functions

Priorities

Reliability

Maintainability

Supportability

Producibility

Operations

Maintenance

Logistics

Life Cycle Cost/Total Ownership Cost

SystemPerformance

SystemAvailability

ProcessEfficiency

TechnicalEffectiveness

SystemEffectiveness

AffordableOperational

Effectiveness

Other Considerations• Software• System Safety• Accessibility• Information Assurance• COTS• Disposal• Human Factors• Environ. Constraints

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Andrew Part I (31 Mar 09) I - 9Part I

Design Solution Methods

• Analyzing each alternative to be able to select the preferred alternative

• Once an alternative is selected or baselined, the Design Solution Definition Process will be used for: – Generating end products as a function of the

hierarchy in the system structure• The output end product Design Solution

Definition will be used for conducting product verification

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Andrew Part I (31 Mar 09) I - 10Part I

Altair Lunar Lander

Interstage

Solid Rocket Boosters (2)• Two recoverable 5.5-segment

PBAN-fueled, steel-casing boosters (derived from current Ares I first stage

J–2XPayload Shroud

RS–68BEngines

(6)

Loiter Skirt

Earth Departure Stage (EDS)• One Saturn-derived J–2X LOX/LH2

engine (expendable)• 10 m (33 ft) diameter stage• Aluminum-Lithium (Al-Li) tanks• Composite structures, Instrument Unit

and Interstage• Primary Ares V avionics system Core Stage

• Six Delta IV-derived RS–68B LOX/LH2engines (expendable)• 10 m (33 ft) diameter stage• Composite structures• Aluminum-Lithium (Al-Li) tanks

Gross Lift Off Mass: 3,704.5 t (8,167.1k lbm)Integrated Stack Length: 116 m (381 ft)Payload Adapter

Two representative configurations shownMultiple configurations for adding a 6th Engine being traded

Ares V Interfaces and Elements 4

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Open Systems & Enabling Product

• A system that implements specifications maintained by an open, public consensus process for interfaces, services, and support formats, to– Enable properly engineered

components to be utilized across a wide range of systems with minimal change,

– Interoperate with other components on local and remote systems, and

– Interact with users in a manner that facilitates portability

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Andrew Part I (31 Mar 09) I - 12Part I

Design Solution Outputs

Subsystems: Subsystems: Initial Initial

SpecificationsSpecificationsfor development of for development of

next lower level next lower level WBS modelsWBS models

Enabling ProductsEnabling Products::Expectations for initiation Expectations for initiation

of development or of development or procurement/reuse of procurement/reuse of

enabling productsenabling products

DevelopmentProducts

End Product

TestProducts

FabricationIntegrationAssemblyproducts

OperationsProducts

LogisticsProducts

Subsystem Subsystem

SystemSpecification

• • •

• • •

Technical Data Technical Data PackagePackageincludes:includes:

•• SpecificationsSpecifications•• DrawingsDrawings•• SketchesSketches•• Parts list Parts list Specific descriptiveSpecific descriptivedocumentation fordocumentation forbuying, building,buying, building,coding or coding or assemblingassembling& integrating end & integrating end products is a products is a function of lifefunction of life--cycle phase and cycle phase and location of WBS location of WBS model in the system model in the system structurestructure

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Andrew Part I (31 Mar 09) I - 13Part I

Modeling and Simulation (M&S)

• Can be an important tool for design process(Provided that models are sufficiently adequate descriptions of reality – they are valid)– Better understand and optimize performance

• Multiple combinations and permutations

– Fly or test more effectively early in the design• More experimentation and data generation without costly

prototypes and tests

• Can save Time and Resources.• Requires Experience and Skill

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M&S is used as a tool throughout the Systems Engineering Process

Andrew Part I (31 Mar 09) I - 14Part I

Benefits of a Designing the Right system

• Meets stakeholder expectations

• Meets cost/schedule and performancerequirements

• Operates as specified in ConOps

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Andrew Part I (31 Mar 09) I - 15Part I

Design Solution Definition – Best Practice Process Flow Diagram

OutputActivities

Input

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Andrew Part I (31 Mar 09) I - 16Part I

Summary

• The Design Solution Definition Process is used to translate the outputs of the Logical Decomposition Process into a design solution definition

• Alternative design solutions must be defined and analyzed to select the best alternative that satisfies technical requirements

• The form of the design solution definition depends on the product life cycle phase and its hierarchy in the system

• The Technical Data Package allows for the building, coding, reusing, or buying of products

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Andrew Part I (31 Mar 09) I - 17Part I

Technical Solution Definition

Discussion

• Where in the Solution Definition Process do we tend most to skip steps (where we should not)?

• Do tight schedules mean we scrimp in the wrong places?

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16.842 Fundamentals of Systems EngineeringFall 2009

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