course overview/systems...

Introduction to Systems EngineeringPrinciples of Space Systems Design

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

Course Overview/Systems Engineering

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

• Systems Design Case Study

© 2006 David L. Akin - All rights reservedhttp://spacecraft.ssl.umd.edu



Contact Information

Dr. Dave AkinSpace Systems Laboratory

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

TA: Peter Gardner (contact info TBD)



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



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



Web-based Course Content

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

• Interactive web site at https://bb.eng.umd.edu/– Communications for team projects– Lecture videos



Syllabus Overview

• Fundamentals of Spacecraft Design• Vehicle-Level Design• Systems-Level Estimation• Component Detailed Design• Team Projects



Syllabus 1: Fundamentals of Space Systems

Systems EngineeringSpace EnvironmentOrbital MechanicsEngineering GraphicsEngineering in TeamsEngineering EthicsEngineering EconomicsDesign Case Studies



Syllabus 2: Vehicle/System-Level Design

Rocket PerformanceParametric AnalysisCost EstimationReliability and RedundancyConfidence, Risk, and ResiliencyMass Estimating RelationsResource Budgeting



Syllabus 3: Component-Level Design• Loads, Structures, and Mechanisms

Loads EstimationStructural AnalysisStructures and Mechanisms Design

• Propulsion, Power, and ThermalPropulsion System DesignPower System DesignThermal Design and Analysis

• Avionics SystemsAttitude Dynamics/Proximity OperationsData Management; GN&CCommunications



Syllabus 4: Component-Level Design

• Crew SystemsSpace PhysiologyHuman Factors and HabitabilityLife Support Systems Design

• Other TopicsAtmospheric EntryRover TechnologiesTopics Supporting 484 Project...



Akin’s Laws of Spacecraft Design - #3

Design is an iterative process. The necessary number of iterations is one more than the number you have currently done. This is true at any point in time.



Grading Policies

• Grade Distribution– 25% Problems– 15% Midterm Exam– 10% Graphics Team Project*– 20% Design Team Project*– 30% Final Exam

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

* Team Grades



ENAE 483 RosterBenic, Christopher AlanBesser, Rebecca LeighDorman, Keri Lyn Easley, Joseph Wilson Felikson, Denis Furgione, Christine Marie Gardner, Victor Hean Gorman, Eric Taylor Kirkpatrick, Jeffrey Kumme Knutsen, Daniel MarkKutty, Prasad Marx, Erin Nicole McCall, Brian Eric Meyer, John Daniel Michael, James Bennett

Nagia, Danielle Ashley Patel, Ronak Arvind Schmidt, Walter Thomas Shah, Jatin Vasant Silliman, John David Smith, Eric Sesto Spatafore, Bradley Martin Spitale, Jenna Marie Superfin, Emil Alexander Tomlinson, Zakiya Alexandr Trout, Julie Nicole Trujillo, DianaUrbina, Jeffry D Walter, Sibylle Frederike Webster, Eric Joshua Westenburger, Gavin



ENAE 788D Roster

Beerman, Adam Farrell Dillow, Barrett England, Gretchen Pauline Kaur, Amandeep Gland, Joseph Lee, Taejoo Jung Lewandowski, Craig Michael Sankaran, Jaganath Liszka, Michael Scott Shoemaker, Michael Andrew Trepp, Samuel Gottlieb Veeraragavan, Ananthanaray



Graphics Team Project

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

• Prepare a viewgraph presentation describing a historical spacecraft or launch vehicle (Note: vehicles, not missions: e.g., “Apollo lunar module”, not “Apollo 17”)

• Topics and teams picked for you• Details linked to course syllabus



Assigned Groups and TopicsSaturn IB Dorman, Keri Lyn Shah, Jatin Vasant Saturn V Kirkpatrick, Jeffrey Kumme Schmidt, Walter Thomas X-20 "Dynasoar" Gardner, Victor Hean Silliman, John David Space Shuttle Felikson, Denis Gorman, Eric Taylor Mercury spacecraft Furgione, Christine Marie McCall, Brian Eric Atlas (Mercury launch version) Easley, Joseph Wilson Walter, Sibylle Frederike Redstone (Mercury launch version) Knutsen, Daniel Mark Spitale, Jenna Marie

Gemini spacecraft Meyer, John Daniel Patel, Ronak Arvind Trujillo, DianaTitan II (Gemini launch version) Beerman, Adam Farrell Dillow, Barrett Apollo Command/Service Module England, Gretchen Pauline Kaur, Amandeep Apollo Lunar Module Gland, Joseph Lee, Taejoo Jung Saturn IB Lewandowski, Craig Michael Sankaran, Jaganath Saturn V Liszka, Michael Scott Shoemaker, Michael Andrew Space Shuttle Trepp, Samuel Gottlieb Veeraragavan, Ananthanaray

Mercury spacecraft Benic, Christopher Alan Michael, James Bennett Atlas (Mercury launch version) Besser, Rebecca Leigh Urbina, Jeffry D Redstone (Mercury launch version) Kutty, Prasad Trout, Julie Nicole Gemini spacecraft Spatafore, Bradley Martin Westenburger, Gavin Titan II (Gemini launch version) Superfin, Emil Alexander Webster, Eric Joshua Apollo Command/Service Module Marx, Erin Nicole Smith, Eric Sesto Apollo Lunar Module Nagia, Danielle Ashley Tomlinson, Zakiya Alexandr



Project for ENAE 483 and 484

“Clean-Sheet” Design for Human Lunar Exploration– President announced the Vision for Space Exploration

(VSE) in January, 2003– NASA developed their preferred architecture for

human return to the moon - “Exploration System Architecture Study” (ESAS)

– Involves developing two new spacecraft and two new heavy-lift launch vehicles - “Project Constellation”

– Intended to optimize reuse of existing shuttle components and infrastructure

– Costs are extremely high and growing rapidly



NASA Constellation Vehicle Concepts

Crew Exploration Vehicle (CEV) - Orion Lunar Surface Access Module (LSAM)

Crew Launch Vehicle (CLV - Ares 1) Cargo Launch Vehicle (CaLV - Ares 5)



ENAE 483/484 Design Project Goals• Develop detailed objectives and requirements

for lunar exploration, both initial and long-term• Examine alternative architectures for program,

focusing on innovative solutions to maximize capabilities while minimizing costs

• Present an alternative to NASA’s Exploration Systems Architecture Study which is faster, more feasible, more flexible, and more farsighted

• Win NASA RASC-AL competition



483/484 Design Project Implementation• Fall Semester

– ~5 person teams working independently– Perform preliminary architecture studies, trade

studies, develop configuration, concept of operations, preliminary vehicle designs

– Preliminary design reviews at end of 483• Spring Semester

– Single (~30 person) design team– Synthesize best architecture from results of 483– Perform detailed design of vehicles and missions– Critical Design Review– “Splinter” team performing design-build-test



ENAE 788D Design Project

• Same project as ENAE 483/484, except all program elements must have relevance to Mars exploration as well

• Single term, teams of 4 students• Best project submitted to RASC-AL competition

in May 2007



Assigned Groups for Design ProjectTeam 7(G) England, Gretchen Pauline Gland, Joseph Lewandowski, Craig Michael Liszka, Michael Scott Team 8(G) Dillow, Barrett Kaur, Amandeep Lee, Taejoo Jung Veeraragavan, Ananthanaray Team 9(G) Beerman, Adam Farrell Sankaran, Jaganath Shoemaker, Michael Andrew Trepp, Samuel Gottlieb

Team 4 Gardner, Victor Hean Kirkpatrick, Jeffrey Kumme Patel, Ronak Arvind Spatafore, Bradley Martin Trout, Julie Nicole Team 5 Felikson, Denis Silliman, John David Spitale, Jenna Marie Superfin, Emil Alexander Westenburger, Gavin Team 6 Furgione, Christine Marie Gorman, Eric Taylor Smith, Eric Sesto Walter, Sibylle Frederike Webster, Eric Joshua

Team 1 Easley, Joseph Wilson Marx, Erin Nicole Michael, James Bennett Tomlinson, Zakiya Alexandr Trujillo, DianaTeam 2 Benic, Christopher Alan Besser, Rebecca Leigh Dorman, Keri Lyn Knutsen, Daniel Mark McCall, Brian Eric Nagia, Danielle Ashley Team 3 Kutty, Prasad Meyer, John Daniel Schmidt, Walter Thomas Shah, Jatin Vasant Urbina, Jeffry D



Course Syllabus

• Maintained on web site (follow links at http://spacecraft.ssl.umd.edu)

• Contains links to reference material, problem sets, solution sets, team project details, etc.

Space Systems Laboratory – University of Maryland

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Utilizing On-Orbit Assembly and Servicing to Enable

Minimum-Cost Space Mission Architectures

David L. AkinMary L. Bowden

Case Study:

AIAA Space 2005 ConferenceLong Beach, CAAugust 31, 2005


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NASA Plan (Monolithic Architecture)• Launch entire mission vehicle on single

heavy-lift vehicle • Launch crew in CEV on human-rated

vehicle• Earth orbit rendezvous docks crew and

CEV to mission spacecraft• Lunar orbit staging site leaves CEV in orbit

while crew descends to lunar surface• Lunar orbit rendezvous for crew to return

to CEV• CEV departs lunar orbit and travels back to

earth (direct atmospheric entry)


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Modular Architecture• Multiple boost modules launched on

EELVs and docked together• Lunar landing/ascent vehicle launched on

EELV and docked to boost module stack• Launch crew in CEV on human-rated EELV• Earth orbit rendezvous docks crew and

CEV to mission spacecraft• Lunar orbit staging site leaves CEV in orbit

while crew descends to lunar surface• Lunar orbit rendezvous for crew to return

to CEV• CEV departs lunar orbit and travels back to

earth (direct atmospheric entry)


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So What’s the Argument?• Both approaches are ELOR (Earth and

lunar orbital rendezvous)• Both approaches use CEV and dedicated

lunar landing vehicle• Both approaches use components from

existing launch systems• Both approaches have identical safety-

critical rendezvous and docking operations


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What are the Issues?

Monolithic ModularPros Minimize orbital

operationsSimpler operations

Maximize use of existing assetsMinimize nonrecurring costs

Cons Develop new large launch vehicles and associated ground infrastructure

Multiple docking operations increase odds of mission failure


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Lunar Program Assumptions• 2 lunar missions/year• First lunar mission 2015• 10 lunar missions total• CEV entry vehicle mass 6000 kg • Lander cabin mass 3000 kg• ELOR mission with CEV as return craft• LOX/LH2 Isp=450 sec• Storables Isp=320 sec• Inert mass fraction δ=0.1 except 0.15 for

landing stage• All launch vehicles asymptotically approach

97% reliability• Rendezvous and docking reliability 99%


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Lunar Mission ΔV RequirementsTo:

From:

Low EarthOrbit

LunarTransferOrbit

Low LunarOrbit

LunarDescentOrbit

LunarLanding

Low EarthOrbit

3.107km/sec

LunarTransferOrbit

3.107km/sec

0.837km/sec

3.140km/sec

Low LunarOrbit

0.837km/sec

0.022km/sec

LunarDescentOrbit

0.022km/sec

2.684km/sec

LunarLanding

2.890km/sec

2.312km/sec


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Candidate Cargo Launch Vehicles• Delta IV Heavy

– 23K kg to LEO– Operational– Unmanned– Representative of

current large EELVs

• In-line SDLV– 125K kg to LEO– Conceptual– Manned heritage


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In-line SDLV Assumptions• $8.4B nonrecurring (published

estimate)• 6 year development cycle• $400M first unit production

(shuttle parallel)• 10 units at 85% learning curve• $285M average flight cost


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Shuttle-Derived CEV Assumptions• $2B nonrecurring (NASA

SVLCM estimate for second stage alone)

• 6 year development cycle• $200M first unit production

(shuttle parallel)• 10 units at 85% learning curve• $144M average flight cost


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Delta IV Heavy Assumptions• RDT&E amortized• $2B nonrecurring for

human rating• $250M first unit• 85 vehicle block buy…• … and 85% learning

curve…• … yields $92M average

cost (includes learning for 255 CBCs)

• 50% production surcharge for 11 human rated units ($138M)


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First Boost Module

Mtotal=23,000 kgMprop=20,700 kgMinert=2300 kgIsp=320 sec


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Orbital Assembly of Boost Modules

Assembly Mass=138,000 kg


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Assembly Ready for Crew Launch

Assembly Mass=161,000 kg


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Earth Departure Configuration

ΔV1=391 m/secΔV2=455 m/secΔV3=542 m/secΔV4=671 m/secΔV5=882 m/sec

1 2 3 4 5 6

Initial Mass=176,400 kg


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Lunar Orbit Arrival

ΔV6=166 m/sec (end of TLI)ΔV6=837 m/sec (LOI burn)


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Lunar Descent Initiation

ΔV6=397 m/sec (start of PDI)


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Lunar Landing

Descent stage: Minert=2250 kgMprop=12,750 kg

Ascent stage:Minert=800 kgMprop=4200 kgMcrew module=3000 kg


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Lunar Orbit DepartureEarth return stage:Minert=900 kgMprop=2110 kgMCEV=6000 kg


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Monolithic Launch Operations• $429M average launch recurring

cost• Average amortized launch cost

$1.45B• 93% probability of individual

mission initiation• Probability of N missions

initiating successfully– 49% 10/10– 85% 9/10– 97% 8/10


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Modular Launch Operations• $829M average launch recurring

cost (includes cost of 5 fleet spares)

• Average amortized launch cost $1.10B

• 73% probability of individual mission initiation (no spares)

• Probability of 10 missions initiating successfully– 16% (no spares)– 71% (2 spares)– 88% (3 spares)– 96% (4 spares)– 99% (5 spares)


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Head-to-Head Launch Comparison2000 Nonrecurring

cost ($M) 10,200

829 Average production

cost per mission ($M)

429

1096 Average amortized cost per

mission ($M)

1449

85 Total production

run10+10

432 NPV discounted

cost per mission ($M)

878


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Sensitivity to Monolithic Costing$432M Baseline NPV

discounted cost per mission

$878M

$432M Development costs cut in

half$508M

$432M Production costs cut in

half$809M

$432M Production is free $740M

$432M All costs cut in half $439M


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Discussion of Reliability• Monolithic architecture loses a mission

when a launch or docking fails• 75% of modular architecture failures occur

on a boost module launch– Plan for “ready alert” spare launch vehicle and

boost module– Continue mission buildup

• LV commonality allows robust spares strategy (boost module, CEV, lander)

• Can work full sparing for monolithic system, but requires both launch vehicle types, pads, etc.


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Discussion of Costs• Cost benefits of modular systems:

– Learning curve effects for large production runs– Minimum “up-front” nonrecurring costs

• Modular systems also benefit from other markets for the same launch vehicles

• Minimal market synergy for monolithic vehicles– In-line SDLV too large (5x current largest vehicle)– SRB-based vehicle offers few intrinsic advantages to

commercial/DOD payloads• Lesson: spend your money flying, not developing

new vehicles (suggested mantra: “flight rate, flight rate, flight rate”)


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Additional Caveats• Didn’t consider costing of mission vehicles

– CEV and lander are comparable for both architectures

– Additional cost advantages to modular system for smaller size/large production of boost modules as compared to monolithic TLI stage

• Modular system is sensitive to docking reliability, but it primarily shows up in spares strategy (low marginal cost for larger production run)

• Could use modular approach with SRB-based CEV launcher - minor overall impact to cost


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Comments on Modular Architecture• Modular system is highly adaptive to new

missions and mass growth (add/subtract modules)

• Standard boost modules provide infrastructure for aggressive on-orbit operations (“space tugs”)

• Even with SDLV heavy-lift vehicles, will have to adopt modular-type operations for Mars missions

• …but it is inelegant, complex, and just plain ugly…



What You Just Saw...

• Orbital Mechanics• Parametric Design• Trade Studies• Reliability Analysis• Cost Estimation• Engineering Economics• Engineering Graphics



Akin’s Laws of Spacecraft Design - #1

Engineering is done with numbers. Analysis without numbers is only an opinion.

course overview/systems...

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