Space Systems Laboratory - Dave Akin's Web Site

Course Overview/Design Project 

• Lecture #01 – August 30, 2012 

• Course Overview 

– Goals 

– Web-based Content 

– Syllabus 

– Policies 

• 2012/13 Design Projects 

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

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© 2012 David L. Akin - All rights reserved 

http://spacecraft.ssl.umd.edu 

Course Introduction/Team Projects 

ENAE 483/788D - Principles of Space Systems Design

Contact Information 

Dr. Dave Akin 

Space Systems Laboratory 

Neutral Buoyancy Research Facility/Room 2100D 

301-405-1138 

dakin@ssl.umd.edu 

http://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 483/788D (Fall) 

– Lecture style, problem sets and quizzes 

– Design as a discipline 

– Disciplinary subjects not contained in curriculum 

– Engineering graphics 

• ENAE 484 (Spring) 

– Single group design project 

– Externally imposed matrix organization 

– Engineering presentations 

– Group dynamics 

– Peer evaluations 


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But... (Recent Changes) 

• Emphasize project content 

– Start 484 project at beginning of 483 

– Build teams for spring term in the fall 

– Add specific lectures for project specialties 

– Provide opportunities for both experimentalists and 

theoreticians 

• “Design/Build/Test/Evaluate” 

– Space equivalent to “design/build/fly” for aero side 

– Parallels mission-level design activities 

– Major system(s) relevant to national programs 


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Web-based Course Content 

• Data web site at http://spacecraft.ssl.umd.edu 

– Syllabus and course information 

– Lecture notes 

– Problems and solutions 

• Collaboration site and lecture videos at https:// 

elms.umd.edu (Blackboard) 

• Akin’s Laws of Spacecraft Design at 

http://spacecraft.ssl.umd.edu/akins_laws.html 


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Akin’s Laws of Spacecraft Design - #1 

Engineering is done with numbers. 

Analysis without numbers is only an 

opinion. 


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Overview of the Design Process 

Program Objectives 

System Requirements 

Increasing complexity 

Increasing accuracy 

Vehicle-level Estimation 

(based on a few parameters 

from prior art) 

Decreasing ability 

to comprehend the “big 

picture” 


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System-level Estimation 

(system parameters based on 

prior experience) 

Basic Axiom: Relative 

rankings between 

competing systems will 

remain consistent from 

level to level 

System-level Design 

(based on disciplineoriented 

analysis) 




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. 


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Syllabus Overview 

• Fundamentals of Spacecraft Design 

- Principles and tools of Systems Engineering 

- Vehicle-level design 

- Systems-level estimation 

• Component Detailed Design 

- Crew systems 

- Avionics 

- Power, Propulsion, and Thermal Analysis 

- Loads, Structures, and Mechanisms 

• Team Projects 


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Syllabus 1: Fundamentals of Space Systems 

• Systems Engineering 

• Space Environment 

• Orbital Mechanics 

• Engineering Graphics 

• Engineering Economics 

• Design Case Studies 


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Syllabus 2: Vehicle/System-Level Design 

• Rocket Performance 

• Parametric Analysis 

• Cost Estimation 

• Reliability and Redundancy 

• Confidence, Risk, and Resiliency 

• Mass Estimating Relations 

• Resource Budgeting 


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Problem Sets 

• Each of the Systems Design lectures (during the 

first third of the course) will have associated 

problem sets 

• These problem sets will form the knowledge basis 

for the midterm exam 


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Syllabus 3: Component-Level Design 

• Loads, Structures, and Mechanisms 

– Loads Estimation 

– Structural Analysis 

– Structures and Mechanisms Design 

• Propulsion, Power, and Thermal 

– Propulsion System Design 

– Power System Design 

– Thermal Design and Analysis 

• Avionics Systems 

– Attitude Dynamics/Proximity Operations 

– Data Management; GN&C 

– Communications 


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Syllabus 4: Component-Level Design 

• Crew Systems 

Space Physiology 

Human Factors and Habitability 

Life Support Systems Design 

• Other Topics 

Case studies (e.g., last year’s project) 

Special lectures for this year’s project(s) 


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Team Design Exercises 

• Each of the four specialty areas will have an 

associated design project 

• This will be performed by teams of 4-5 students - 

I will assign people to each team 

• The results of the design exercise will be 

submitted as presentation slides (PowerPoint or 

equivalent) 

• Team grades will be assigned for each design 

exercise, including adherence to the principles of 

the engineering communications lecture 


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Course Syllabus 

• Maintained on web site (follow links or 

http://spacecraft.ssl.umd.edu/academics/ 

483F12/483F12.index.html) 

• Contains links to reference material, problem sets, 

solution sets, team project details, etc. 

• Notes and announcements will be posted at top of 

syllabus page as necessary 

• Every class has associated homework content; 

every homework has a full solution set posted after 

homework due date 


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Fall 2012 Initial Syllabus (1) 


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Fall 2012 Initial Syllabus (2) 


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Grading Policies 

• Grade Distribution 

– 20% Homework Problems 

– 20% Midterm Exam 

– 30% Team Design Exercises* 

– 30% Final Exam 

• Late Policy 

– On time: Full credit 

– Before solutions: 70% credit 

– After solutions: 20% credit 


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* Team Grades 



A Word on Homework Submissions... 

• Good methods of handing in homework 

– Hard copy in class (best!) 

– Scanned copies via e-mail (please put “ENAE483” or 

“ENAE788D” in subject line) 

• Methods that don’t work so well 

– Leaving it in my mailbox (particularly in EGR) 

– Leaving it in my office 

– Spreadsheets or .m files 

– Handing it to me in random locations 

– Handing it to Dr. Bowden 


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A Word about Homework Grading 

• Homework is graded via a discrete filter 

– ✓ for homework problems which are essentially 

correct (10 pts) 

– ✓- for homework with significant problems (7 pts) 

– ✓-- for homework with major problems (4 pts) 

– ✓+ for homework demonstrating extra effort (12 pts) 

– 0 for missing homework 

• A detailed solution document is posted for each 

problem after the due date, which you should 

review to ensure you understand the techniques 

used 


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Selection of Class Projects 

• Criteria - needs to be 

– a significant engineering challenge 

– of relevance to the current or future space program 

– requiring the use of tools from 483 and prior classes 

– and of appropriate scope for this class. 

• Preferable to be appropriate for entry into design 

competitions 

• My personal preference is to look at topical issues 

and pursue options not currently being considered 

in detail by NASA 


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NASA’s Space Exploration Program 

• Developing Saturn V-class launch vehicle (“Space 

Launch System” or SLS) and 4-person spacecraft 

(“Multi-Purpose Crewed Vehicle” or MPCV) 

• SLS will cost between $20B and $40B, starting at 

70 MT payload and evolving to 130 MT 

• No human flights until ~2020; start developing 

lunar landing vehicle then - first human lunar 

landing probably 2029-2030 


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Logistics and Operations versus 

Heavy Lift: Examining Approaches to 


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Human Exploration in a 

Cost-Constrained Era 

David L. Akin 

AIAA Paper 2011-7221 

Space 2011 Conference 

Space Systems Laboratory

Amundsen-Scott South Pole Station 


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Logistics Support for Station Construction 


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• 24,000,000 pounds of 

hardware and 

consumables 

• Flown in on 925 flights 

of existing LC-130 

cargo aircraft 

• Mean average 

temperature -47°C 

•

Parallels in Transport Systems? 

LC-130 

11,800 kg payload 


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Delta IV Heavy 

23,000 kg payload to LEO 

9980 kg to LTO 


Study Phase 1 Summary 

• AIAA Paper 2010-2293, SpaceOps 2010 

• Assumptions: 

– Delta IV Heavy only 

– In-space use of storable hypergolics only 

– No propellant depots or transfers 

– Keep annual funding ≤ $3B 

• Focus of study effort 

– Feasibility of modular vehicle performance for lunar 

landing 

– Assessment of cost benefits of large production and 

flight rates 


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Notional Program Elements 

Crew Vehicle 

4990 kg 


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Lunar Landing 

Module (LLM) 

6950 kg 

Orbital Propulsion 

Module (OPM) 

6950 kg 


Single Launch Lunar Cargo Mission 


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Landed Cargo 1890 kg 

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LLO Staging for Human Lunar Landing 


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Notional Vehicle in Landing Configuration 


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Comparison of Lunar Landing Vehicles 


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Results of Phase 1 Study 

• Use direct injection into Lunar transfer orbit and 

perform all in-space operations in low Lunar orbit 

(LLO) 

• Develop three vehicles based on LTO payload of 

DIVH and mutual performance 

– Orbital Maneuvering Stage (OMS) 

– Terminal Landing Stage (TLS) 

– Crew Module 

• Adapt standard modules to specific missions 

through multiple stages, offloading propellant 


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Year-by-Year Program Costs 


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Study Phase 2 Summary 

• AIAA Paper 2010-8610, Space 2010 

• Assumptions: 

– Mixed launch fleet (Delta IV Heavy and Atlas 402) 

– In-space use of storable hypergolics only 

– No propellant depots or transfers 

– Keep annual funding ≤ $3B 

• Focus of study effort 

– Probabilistic risk analysis of multilaunch missions 

– Cost incorporation of (limited) multiple launch vehicles 


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Monolythic vs. Modular Reliability 


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Design Reference Mission 


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Annual Program Expenditures 

85% Learning Curve used for all repetitive production 


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Focus of This Study (Phase 3) 

• Improve accuracy of vehicle design estimates 

– Incorporate mass dependence of stage inert mass 

fraction 

– Investigate sensitivity to specific impulse assumptions 

• Revisit lunar architecture with revised vehicle 

parameters 

• Extend architecture to near-Earth objects (NEOs) 

and Mars orbit destinations 

• Perform trade studies for phased introduction of 

additional technologies 


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Cost Sensitivity to Vehicle Size 


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Sensitivity to Specific Impulse 


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Comparison of New Module Parameters 

OPM 

LLM 


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Lunar Cargo Mission Performance 


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Human Lunar Landing Configuration 


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Implications of Parametric Resizing 

• Reduced OPM performance eliminates singlemodule 

lunar ascent option 

– Two OPMs landed for ascent with partial fueling in first 

stage 

– Both OPMs are single failure points for ascent 

• Since abort-to-orbit option exists throughout 

descent, no change in crew safety for that phase, 

but additional risk to mission success 

• Introduce option for larger vehicles → assume 

Falcon Heavy availability (16,000 kg to TLI) 


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OPM Parameters for FH Variant 


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Lunar Landing Configuration Options 


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Assessment of FH Module Options 

• Use of OPM-F for ascent propulsion provides 

maximum reliability 

• Either of the last two options (all OPM-F or all 

OMP-F/LLM-F) provide human lunar surface 

missions with six launches, and are acceptable for 

lunar exploration program 


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Future Work 

• Better graphics! 

• Detailed design of vehicles (crew module, propulsion 

modules) 

• Perform analysis for forward-staging modules in low 

Martian orbit for cargo and human Mars surface access 

• Perform reliability and costing analyses for NEO and 

Mars cases 

• Develop overall program design incorporating phased 

development of additional capabilities (Falcon Heavy 

modules, LEO staging modules, LOX/LH2 stages) into 

active mission model with budget caps 

• Consider additional advanced technologies (orbital 

depots, aerobraking, reusability) for future missions 


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Conclusions 

• Use of simple existing technologies still provides 

early, affordable, repeatable human access to the 

lunar surface 

• More conservative vehicle estimates support use 

of larger launch vehicles if available 

• Deep space missions should be staged in LEO 

• Long-duration LOX/LH2 stages facilitate NEO 

missions and are highly advantageous for Mars 

• An evolutionary program concept using on-orbit 

staging will provide a robust, ongoing human 

exploration program without waiting for the 

development of super-heavy lift vehicles 


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A Few Additional Notes 

• All of these papers are posted on the web site 

under Lecture #01 

• Fourth paper in the series in preparation for AIAA 

Space 2012 conference; preprint will be available 

next week 

• This material is presented only as point of 

departure (POD); it is to provide some initial 

guidance, not to be accepted as “gospel” 

• I expect the 42 of you to go into much greater 

depth of design analysis than I did on my own! 


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Organization of the Design Project 

• You will be divided into three cooperating teams: 

– Human spacecraft design team 

– Transportation design team 

– Surface systems design team 

• There will also be a program-level systems 

integration and mission planning team 

• All of the design projects this term will be directly 

applicable to the capstone project for 484 


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Design/Build/Test/Evaluate 

• Hardware design, fabrication, and testing will be an 

integral part of the 484 capstone project 

• A requirement for this term is to figure out what 

you’re building next term 

• Choice is based on 

– Getting design data unobtainable by analysis (e.g., 

human factors evaluation of crew capsule interior) 

– Enabling meaningful mission simulations 

– Providing value for competitions 

• Leveraging facilities and infrastructure of SSL 


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End Goal: RASC-AL Competition 


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Matrix Organization 

• Each project team is divided into six specialty 

groups 

– Systems Integration (SI) 

– Mission Planning and Analysis (MPA) 

– Loads, Structures, and Mechanisms (LSM) 

– Power, Propulsion, and Thermal (PPT) 

– Crew Systems (CS) 

– Avionics and Software (AVS) 

• You will be assigned to a project and a specialty 

group - but you do get to express your preferences 


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Systems Integration 

• Overall coordination of design activities 

• Creation and tracking of budgets, particularly mass 

and cost 

• Maintenance of canonical system configuration 

documents 

• Vehicle- and system-level trade studies 

• Cost estimation 

• Tracking of vehicle center of gravity and inertia 

matrix 

• Advanced technology (e.g., robotics, EVA) 


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Mission Planning and Analysis 

• Creation and maintenance of design reference 

mission(s) (DRM) 

• Orbital mechanics and launch/entry trajectories 

• Determination of operational mission objectives 

• Concept of operations (CONOPS) 

• Programmatic planning (sequence of missions) 

• Science instrument/payload definition 


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Loads, Structures, and Mechanisms 

• Identification and estimation of loads sources 

• Structural design and analysis 

– Selection of structural shapes and materials 

– Stress modeling 

– Deformation estimation 

– Design optimization 

• Design of mechanisms (docking/berthing ports, 

separation mechanisms, launch holddowns, engine 

gimbals)) 

• Tracking of critical margins of safety 


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Power, Propulsion, and Thermal 

• Electrical power generation 

• Energy storage 

• Power management and conditioning 

• Primary propulsion (orbital maneuvering) 

• Reaction control system (rotation/translation) 

• Design of propellant storage and feed systems 

• Thermal modeling and analysis 

• Thermal control systems 

• Power budgets 


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Crew Systems 

• Internal layout 

• Emergency egress systems 

• Lighting and acoustics 

• Window and viewing analysis 

• Life support systems 

– Air revitalization 

– Water collection and regeneration 

– Cabin thermal control 

– Waste management 

– Food and hygiene 

• EVA accommodations 


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Avionics and Software 

• Data management (flight computers) 

• Networking 

• Sensors 

• Power distribution 

• Guidance system 

• Control systems, including attitude control 

• Communications 

• Robot control systems 

• Software 

• Data transmission budgets 


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The previous people who did a similar 

analysis did not have a direct pipeline to the 

wisdom of the ages. There is therefore no 

reason to believe their analysis over yours. 

There is especially no reason to present 

their analysis as yours. 


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The fact that an analysis appears in print 

has no relationship to the likelihood of its 

being correct. 


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ENAE 788D Design Project – 2012 

• Grad students will form a team for the four design 

projects throughout the term 

• Grads will also perform systems analyses and 

mission design for the same lunar program for the 

484 capstone project 

• Grads will complete their project and give a final 

presentation on their results on the last day of the 

term 


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(de Saint-Exupery's Law of Design) A 

designer knows that he has achieved 

perfection not when there is nothing 

left to add, but when there is nothing 

left to take away. 


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Documentation 

• In a group of 42 people, there are 861 possible 

communication paths between two people 

• Results and decisions you make will inevitably 

affect everyone else in the team 

• The 484 final report should be a comprehensive 

documentation of everything all 42 of you did on 

the project over this academic year 

• Document! Use archival electronic media (forums 

and postings on Blackboard) rather than informal 

(chat rooms, texts, e-mails) 

• If I can’t see it, you don’t get credit for it 


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When in doubt, document. 

(Documentation requirements will 

reach a maximum shortly after the 

termination of a program.) 


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Closing Comments 

• Focus on numerical analysis and systems 

engineering → this is not “hardware-bashing” 

• Look for your own design solutions → this is also 

not “catalog shopping” 

• Approach everything rigorously with numbers → 

this is also also not “adjective engineering” 

• Manage scope and risk along with cost, mass, and 

other design parameters 

• Be innovative, while remaining real 

• What you get out of the process is directly 

proportional to what you put in 


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Today’s Assignment 

• Download and read the POD papers from the 

spacecraft web site 

• Watch the clip on the design of the Apollo Lunar 

Module from the episode “Spider” from the miniseries 

“From the Earth to the Moon” (posted) 

• Do assignment posted on http:// 

spacecraft.ssl.umd.edu under Lecture #01(due 

Thursday 9/6) 


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Not having all the information you need is 

never a satisfactory excuse for not starting 

the analysis. 


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