course overview/systems...

Course Overview/Systems EngineeringPrinciples of Space Systems Design

U N I V E R S I T Y O F

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Course Overview/Systems Engineering

• Course Overview– Goals– Web-based Content– Syllabus– Policies– Project Content

• Tools of Systems Engineering– History– Project Organization– Task-based Management

© 2003 David L. Akin - All rights reservedhttp://spacecraft.ssl.umd.edu



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Contact Information

Dr. Dave AkinSpace Systems Laboratory

Neutral Buoyancy Research Facility/Room [email protected]://spacecraft.ssl.umd.edu



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Goals of ENAE 483/484 (and 788D)• Learn the basic tools and techniques of systems

analysis and space vehicle design• Understand the open-ended and iterative nature

of the design process• Simulate the cooperative group engineering

environment of the aerospace profession• Develop experience and skill sets for working in

teams• Perform and document professional-quality

systems design of focused space mission concepts



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Outline of Space Systems

• ENAE 483 (Fall)– Lecture style, problem sets and quizzes– Design as a discipline– Disciplinary subjects not contained in curriculum– Engineering graphics– Engineering ethics

• ENAE 484 (Spring)– Single group design project– Externally imposed matrix organization– Engineering presentations– Group dynamics– Peer evaluations



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Web-based Course Content

• Data web site at spacecraft.ssl.umd.edu– Course information– Syllabus– Lecture notes– Problems and solutions

• Interactive web site at www.ajconline.umd.edu– Communications for team projects– Surveys for course feedback



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Syllabus Overview

• Fundamentals of Spacecraft Design• Vehicle-Level Estimation and Design• Discipline-Level Detailed Design



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Syllabus 1: Fundamentals of Space Systems

9/2 - Systems Engineering9/4 - Space Environment9/9 - Orbital Mechanics9/11 - Engineering Graphics9/16 - Engineering Ethics9/18 - Rocket Performance/Multistaging9/23 - Engineering in Teams9/25 - Design Case: Project SCOUT



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Syllabus 2: Vehicle-Level Design

9/30 - Parametric Analysis10/2 - Cost Analysis10/7 - Mass Estimating Relations and Budgets10/9 - Reliability, Redundancy, and Resiliency10/14 - Advanced Costing Analysis



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Syllabus 3: Discipline-Level Design• Propulsion, Power, and Thermal

10/16 - Propulsion System Design10/21 - Power System Design10/23 - Thermal Design and Analysis

• Loads, Structures, and Mechanisms10/28 - Structural Design and Analysis

10/30 - Midterm Examination11/4 - Structural Practices

• Crew Systems11/6 - Space Physiology11/11 - Life Support Systems Design11/13 - Human Factors and Habitability



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Syllabus 4: Discipline-Level Design

• Avionics Systems11/18 - Navigation and Guidance11/20 - Data Management and Information

Technology11/25 -Communications, Command, and Control

11/27 - Thanksgiving Break12/2 - Scheduling Margin12/4 - Scheduling Margin12/9 - Team Project 2 Presentations12/16 - Team Project 2 Presentations



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Policies

• Grade Distribution– 20% Problems– 20% Midterm Exam– 10% Team Project 1*– 20 % Team Project 2*– 30% Final Exam

• Homework Late Policy– On time: Full credit– Before solutions: 70% credit– After solutions: 20% credit

* Team Grades



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Projects for ENAE 483 - Fall 2002

Project Diana– Minimum cost and time system for resuming human

lunar exploration– “Pathfinder” project to illustrate techniques and

applications this term– Single-person project (me!)



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Projects for ENAE 483 - Fall 2002

• Team Project 1 (2-3 person teams)– Research a spacecraft from history (real or

planned)– Prepare an engineering overview presentation– Emphasis on research and graphics skills

• Team Project 2 (4-5 person teams)– Perform preliminary design of a space vehicle– Should follow along with lecture syllabus– Presentations at end of term– Lead-in to ENAE 484



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Team Project 1

• Intended to give you a start at systems engineeringand group dynamics– Picking and operating in small teams– How to perform research– Engineering graphics– Technical presentation preparation

• Prepare a viewgraph presentation describing a spacevehicle - Could be past, present, or planned for future,flown or unflown - but not science fiction! (Note:vehicles, not missions: e.g., “Apollo lunar module”, not“Apollo 17”)

• Details linked to course syllabus



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Team Project 2

• Orbital Space Plane– Rotate crews to/from International Space

Station– Based on ISS for emergency “bail-out”– Launch on EELV (Delta or Atlas)– Use same assumptions and documents as OSP

contractors• Design process should proceed throughout

the term• Formal design presentations at end of term



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Class Rosters• ENAE 483

Albritton, John WesleyBalkam, Matthew RichardBurley, Tia AlbertaButani, Shawn DCastell, Kathleen AnneCavaluzzi, Joseph EarlDaiub, Abraham ManuelEisenhower, Kevin CarlFarrell, Thomas PaulFelsecker, Alan JHasan, Syed OHerda, Paula CeciliaHughes, Matthew RobertMacko, Kevin Timothy

• ENAE 788DChung, Lauren RoseDoi, ShinobuFrigm, Ryan ClaytonGhosh, AmardipHack, James SamuelKoelln, Nathan ThomasRaymond, Juan C

• ENAE 483McGhan, Catharine LinetNaylor, Michael PearsonNazir, AdeelNickel, Craig AlanParker, John MichaelParker, Russell LawrencePullen, David KeatsSeabrease, Jason MichaelSeidel, Jessica LouiseSenai-Alemou, DanielTai, Emily MinwaiTwarek, Luke MichaelWinter, Robert MarkYamamoto, Susumu



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Project for ENAE 484 - Spring 2002

OSP - Cornerstone for Exploration• NASA is committed to developing Orbital Space

Plane for replacing the shuttle• How can OSP enable advanced exploration

missions?• What changes need to be made in OSP to

facilitate more ambitious missions?• Build from base of Clarke Station, SCOUT, best

products of Team Project 2



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Akin’s Laws of Spacecraft Design - #3

Design is an iterative process. Thenecessary number of iterations is onemore than the number you havecurrently done. This is true at anypoint in time.



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Overview of Systems Engineering

• Developed to handle large, complex systems– Geographically disparate– Cutting-edge technologies– Significant time/cost constraints– Failure-critical

• First wide-spread applications in aerospaceprograms of the 1950’s (e.g., ICBMs)

• Rigorous, systematic approach to organizationand record-keeping



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The Space System Development Process

Pre-Phase A Conceptual Design PhaseDevelopment of performance goalsand requirementsEstablishment of Science WorkingGroup (science missions)Trade studies of mission conceptsFeasibility and preliminary costanalysesRequest for Phase A proposals



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Pre-Phase A

Phase A

Preliminary Analysis PhaseProof of concept analysesMission operations concepts“Build vs. buy” decisionsPayload definitionSelection of experimentersDetailed trajectory analysisTarget program scheduleLevel 1 Requirements



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Effect of Study Phase Investment

0 5 10 15 20 250

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Study Phase Cost as a Percentof Development Cost

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Data points shown are for 26space programs including: • Hubble Space Telescope • TDRSS • Gamma Ray Obs 1978 • Gamma Ray Obs 1982 • SeaSat • Pioneer Venus • V oyager



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Pre-Phase A

Phase B

Phase A

Definition PhaseDefine baseline technical solutionsComplete requirements documentComplete block diagrams andinterface definitionsAllocations of functions andresourcesDrawing package 50% completeCulminates in Preliminary DesignReview



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Pre-Phase A

Phase C/D

Phase B

Phase A

Design Phase (Phase C)Detailed design processDrawing package 95% completeCulminates in Critical DesignReview



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Pre-Phase A

Phase C/D

Phase B

Phase A

Development Phase (Phase D)“Cutting metal”Test and analysisSignificant reviews:

Test Acceptance ReviewFlight Readiness Review

Build, test, verify, integrate,launch, and prepare for on-orbitoperations



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Pre-Phase A

Phase E/F

Phase C/D

Phase B

Phase A

Operations and End-of-LifeMission OperationsMaintenance and TroubleshootingFailure monitoringEnd-of-life disposal



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Requirements Document

• The “bible” of the design and developmentprocess

• Lists (clearly, unambiguously, numerically) whatis required to successfully complete the program

• Requirements “flow-down” results in successivelyfiner levels of detail

• May be subject to change as state of knowledgegrows

• Critical tool for maintaining program budgets



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OSP Level 1 Requirements (1)

1) The system, which may include multiple vehicles, shallprovide rescue capability for no fewer than four ISScrew as soon as practical but no later than 2010.

2) The system shall provide rescue capability that allowsthe safe return of deconditioned, ill or injuredcrewmembers with ongoing treatment until arrival atdefinitive medical care within 24 hours. Crew shouldnot require suits in the vehicle, but the vehicle shouldsupport crew wearing suits if the situation warrants.

3) The system for rescue shall provide for rapidseparation from the ISS under emergency conditionsfollowed by return to Earth.



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4) Safety requirements - system for crew rescue:a) The availability (defined as "a full-up vehicle able to perform its

mission") for the escape mission shall be at least: -- Objective:99% -- Minimum Threshold: 95%.

b) The risk of loss of crew shall be, with high confidence, lowerthan the Soyuz for the rescue mission.

5) The system shall provide transportation capability forno fewer than four crew to and from the ISS as soon aspractical but no later than 2012.

6) Safety requirement - system for crew transport: Therisk of loss of crew shall be, with high confidence, lowerthan the Space Shuttle for the transport mission.



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7) The system shall be designed for minimum lifecycle cost.

8) The system shall meet all applicable ISSrequirements for visiting and attached vehicles.

9) Compared to the Space Shuttle, the system shallrequire less time to prepare and execute amission and have increased launch probability.

10)Compared to the Space Shuttle, the system shallhave increased on-orbit maneuverability.



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OSP Operations Concept

1) The vehicle(s) shall initially launch on an ELV.2) The system shall be operated through at least

2020. However, the system should be designedso that it could be operated for a longer time.

3) NASA envisions that the systems for crewrescue and crew transport could be differentversions of the same vehicle design.

4) The system shall provide contingency capabilityfor cargo delivery to or from the ISS to supporta minimal level of science.

5) The system shall support a nominal ISS crewrotation period of 4-6 months.

Space Systems Laboratory – University of Maryland

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Project Diana Mission StatementPresidential address to a joint session of

Congress, January, 2004:

“I believe this nation should commit itselfto achieving the goal, before this decade isout, of returning humans to the lunarsurface, for exploration and eventualpermanent habitation.”


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Level 1 Requirements1) Perform a mission equivalent to a NASA J-

class Apollo mission before January 1,2010

2) No programmatic resources may be usedfor launch vehicle development

3) Any single mission shall have a 90%chance of mission success

4) Any single mission shall have a 99.9%chance of crew survival

5) The program will maximize theopportunities to engage and involve theU.S. and world public, especially K-12


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Level 2 Requirements1.1) At least two astronauts will form the

lunar landing crew1.2) Lunar surface stay time will be at least

72 hours1.3) Lunar surface activities will be

comparable to Apollo J missions


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Level 3 Requirements1.3.1) Landed lunar equipment mass will be

TBD kg1.3.2) Returned lunar sample mass will be

TBD kg1.3.3) Surface activities will include 3 EVAs of

7 hours duration each



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Design is based on requirements. There's nojustification for designing something one bit"better" than the requirements dictate.




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Work Breakdown Structures• Detailed “outline” of all tasks required to

develop and operate the system• Successively finer levels of detail

– Program (e.g., Space Transportation System)– Project (Space Shuttle Project)– Mission (Earth-LEO Transportation)– System (Shuttle Orbiter)– Subsystem (Main Propulsion)– Assembly (High Pressure LOX Turbopumps)– Subassembly, Component, Part, ...



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It's called a "Work BreakdownStructure" because the Workremaining will grow until you have aBreakdown, unless you enforce someStructure on it.



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Technology Readiness LevelsTRL 1 - Basic principles observed and reportedTRL 2 - Technology concept and/or application formulatedTRL 3 - Analytical and experimental critical function and/or

characteristic proof-ofconceptTRL 4 - Component and/or breadboard validation in laboratory

environmentTRL 5 - Component and/or breadboard validation in relevant environmentTRL 6 - System/subsystem model or prototype demonstration in a

relevant environment (ground or space)TRL 7 - System prototype demonstration in a space environmentTRL 8 - Actual system completed and “flight qualified” through test and

demonstration (ground or space)TRL 9 - Actual system “flight proven” through successful mission

operations



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Space Systems Architecture

• New addition to space systems lexicon• Addresses questions of appropriate

infrastructure for future missions• Focused on operations concepts• Not to be confused with Space

Architecture, which brings architecturalprincipals to space systems design(primarily habitats and habitability)



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Lecture 1

1d 0dTue 9/3/02 Tue 9/3/02

Prepare for Lecture 2

2d 0dWed 9/4/02 Thu 9/5/02

Homework 1

2d 0dWed 9/4/02 Thu 9/5/02

PERT Charts

Task Title

Slack TimeTaskDuration

EarliestStarting Date

LatestCompletion Date



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The Critical Path and Slack Time

Build Head

6 w 0dTue 10/1/02 Mon 11/11/02

Assemble

2 w 0dTue 11/12/02 Mon 11/25/02

Build Body

4 w 10dTue 10/1/02 Mon 11/11/02

Build Legs

3 w 15dTue 10/1/02 Mon 11/11/02

Design Robot

4 w 0dTue 9/3/02 Mon 9/30/02



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Build Head

6 w 5dTue 10/1/02 Mon 11/18/02

Assemble

2 w 0dTue 11/19/02 Mon 12/2/02

Build Legs

3 w 20dTue 10/1/02 Mon 11/18/02

Design Robot

4 w 0dTue 9/3/02 Mon 9/30/02

Build Body

7 w 0dTue 10/1/02 Mon 11/18/02

The Critical Path and Slack Time



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Cascading Slack Time

Assemble

2 w 0dTue 11/12/02 Mon 11/25/02

Build Torso

2 w 10dTue 10/1/02 Mon 10/28/02

Build Legs

3 w 15dTue 10/1/02 Mon 11/11/02

Design Robot

4 w 0dTue 9/3/02 Mon 9/30/02

Build Waist

2 w 10dTue 10/15/02 Mon 11/11/02

Build Head

6 w 0dTue 10/1/02 Mon 11/11/02



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Gantt Charts

I D Task Name Durat i on S t a r t F i n i s h P r edeces so r s1 Design Robot 4 w Tue 9/3/02 Mon 9/30/022 Build Head 6 w Tue 10/1/02 Mon 11/11/02 13 Build Body 4 w Tue 10/1/02 Mon 10/28/02 14 Build Legs 3 w Tue 10/1/02 Mon 10/21/02 15 Assemble 2 w Tue 11/12/02 Mon 11/25/02 2,3,4

9/1 9/8 9/15 9/22 9/29 10/6 10/13 10/20 10/27 11/3 11/10 11/17 11/24 12/1 12/8September October November December



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The schedule you develop will seem likea complete work of fiction up until thetime your customer fires you for notmeeting it.



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Engineering is done with numbers.Analysis without numbers is onlyan opinion.

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