AER817-Quizzes-2016.pdf

1 AER 817: Systems Engineering Solution to Quiz Date: Oct. 11, 2016 Marks: 10 Student Name: Student ID: 1. [Marks 5] Answer the following questions: i) [Marks 1-1/2] State whether the following sentences regarding System Engineering are True or False: a) System Engineering guides the engineering of a system through its life-cycle. True b) System Engineers require a broad view of a specific discipline. False c) Risk Management is performed by the system engineer and project manager. True d) The first stage of the life-cycle is Preliminary Analysis. False e) The trade study process allows one to select the optimum solution based upon the given criteria/constraints. True Ans. a) True, b) False, c) True, d) False, e) True ii) [Mark 1/2] Which task is NOT something that a system engineer would perform? Choose one a) Trade-Off Analysis of a new space transportation system b) Verify a requirement that imposes a solar radiation constraint c) Design a capacitor to meet the demand of the HI that it will be installed in d) Attend a risk working group meeting Ans. c iii) [Mark 1/2] Reviews are known as _______ allowing a project to progress across a life cycle Choose one a) Barriers b) Gates c) Pass-through d) None of the above Ans. b

2 iv) [Mark 1/2] Which is not a system engineering function? Choose one a) Disposal b) Verification c) Support d) Planning Ans. d v) [Mark 1/2] The WBS does all of the following except: Choose one a) Defines all of the tasks to be accomplished during the project in terms of a hierarchical structure b) Provides a method for cost control and estimating c) Links program objectives and activities with resources d) Defines the location of facilities to perform the associated tasks Ans. d vi) [Mark 1/2] Detailed designs are addressed by a a) Preliminary Design Review b) Critical Design Review c) Both A. and B d) None of the above Ans. b vii) [Mark 1/2] The system engineering process usually begins with the a) detailed view b) domain view c) element view d) world view Ans. d

3 viii) [Mark 1/2] For the systems engineering Vee Diagram below, state whether the following sentences are true or false: a) Left Arrow: Decomposition and Definition Sequence , Right Arrow: Integration and Verification Sequence, Horizontal Arrow: Time and Project Maturity. True b) Left Arrow: Integration and Verification Sequence, Right Arrow: Decomposition and Definition Sequence, Horizontal Arrow: Time and Project Maturity. False c) Left Arrow: . Time and Project Maturity, Right Arrow: Integration and Verification Sequence, Horizontal Arrow: Time and Project Maturity. False d) Left Arrow: . Time and Project Maturity, Right Arrow: Decomposition and Definition Sequence, Horizontal Arrow: Integration and Verification Sequence. False Ans. a) True, b) False, c) False, d) False 2. [Mark 1] State whether the following sentences with regard to validation and verification of requirements are true or false: a) Validation: ensuring requirement is correct, complete, well-defined, meets need of customer; b) Verification: ensuring requirement is correct, complete, well-defined, meets need of customer; c) Validation: ensuring that the system as designed and built meets the stated requirements d) Verification: ensuring that the system as designed and built meets the stated requirements Ans. a) True, b) False, c) False, d) True Mission Requirements & Priorities System Demonstration & Validation Develop System Requirements & System Architecture Allocate Performance Specs & Build Verification Plan Design Components Integrate System & Verify Performance Specs Component Integration & Verification Verify Component Performance Fabricate, Assemble, Code & Procure Parts

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4 3. [Marks 3] State whether the following sentences are valid requirements (True or False): a) The rover must be compatible with the lunar communications network, providing data, video, and audio capability. b) The crew shall handle the specimens using a glovebox. c) The ABC Aircraft 505 shall carry 200 passengers and baggage. d) The ABC Aircraft 505 shall never crash. e) The ABC Aircraft 505 will carry 2000 lbs of fuel. f) The ABC Aircraft 505 shall be the most comfortable aircraft in service by the year 2010. Ans. a) False, b) False, c) True, d) False, e) False, f) False 5. [Mark 1] Match definitions with key systems engineering terms, using the word bank below. WORD BANK: a) functional analysis b) spacecraft bus c) margin d) mission scope e) heritage f) objective g) analytical hierarchy process h) need i) figures of merit j) descope k) systems engineering l) payload m) allocated baseline n) goal o) product baseline p) cost benefit analysis q) Taguchi method r) contingency s) design parameter t) six sigma u) concept of operations Explains why the project is developing this system from the stakeholders’ point of view. A robotic vehicle that provides house-keeping functions in the form of subsystems, such as power and temperature control. Ans. h Explains why the project is developing this system from the stakeholders’ point of view. b A robotic vehicle that provides house-keeping functions in the form of subsystems, such as power and temperature control.

1 AER 817: Systems Engineering Solution to Quiz Date: Nov. 1, 2016 Marks: 10 Student Name: Student ID: Section Number: 1. [Marks 5-1/2] Answer the following questions: i) [Mark 1/2] A new microprocessor "M1" will hit the market while the next-generation microprocessor "M2" is currently being prototyped. State the Technological Readiness Levels (TRLs) of M1 and M2. a) TRL (M1)=9, TRL (M2)=4 b) TRL (M1)=9, TRL (M2)=3 c) TRL (M1)=8, TRL (M2)=2 d) TRL( M1)=7, TRL (M2)=1 Ans. (b) TRL (M1) =9, TRL (M2)=3 ii) [Mark 1/2] A Ryerson pico-satellite RyePicoSat-1 comprises of the following subsystems: Structure Subsystem, ADCS Subsystem, Payload Subsystem, C&DH Subsystem, Communication Subsystem, and Power Subsystem. The Technological Readiness Levels (TRLs) of these subsystems are as follows: Structure Subsystem: TRL 9 ADCS Subsystem: TRL 4 Payload Subsystem: TRL 3 C&DH Subsystem: TRL 5 Communication Subsystem: TRL 8 Power Subsystem: TRL 9 What will be the TRL of the RyePicoSat-1: a) 4 b) 6 c) 3 d) 5 Ans. c) 3.

2 iii) [Mark 1/2] An internal interface can be defined as" "Those boundaries between a system end product and another system end product". a) False b) True Ans. a) False iv) [Mark 1/2] Failure Mode Effects Analysis (FMEA) is initiated in which phase of the project life-cycle: a) Phase A b) Phase B c) Phase C d) Phase D e) Phase E f) Phase F Ans. b) Phase B (Preliminary Design) v) [Mark 1/2] When is the risk and uncertainty in a project's life cycle at the highest? a) Phase A b) Phase B c) Phase C d) Phase D e) Phase E f) Phase F Answer: a) Phase A vi) When choosing between possible solutions to an engineering problem, the best solution is the one with the fewest risks and the most benefits. a) False b) True Answer: b) True vii) A predictive systems development life cycle has a high technical risk. a) False b) True Answer: a) False

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3 viii) [Mark 1/2] A new project that was initiated, involved new technology and had never been done before. What type of contract would the owner want to issue to reduce or eliminate as much risk as possible? a) fixed price b) Cost plus fix fee c) Cost plus incentive fee d) Time and Material Answer: a) fixed price Hint: A fixed bid project has lesser risk for the firm that gives high-risk work on contract ix) [Mark 1/2] Which of the following fit the category of external risks? a) Project delays, budget under-runs, movement of city utilities b) Regulatory, currency changes, taxation c) Natural disasters, regulatory, design d) Inflation, design, social impact e) Political unrest, budget overruns, size and complexity of the project Answer: b) Regulatory, currency changes, taxation x) [Mark 1] What’s the difference between Interface Control Document or Interface Control Drawing (ICD) and Interface Definition Document (IDD)? Ans. Interface Control Document or Interface Control Drawing (ICD)- Details the physical interface between two system elements, including the number and types of connectors, electrical parameters, mechanical properties, and environmental constraints. The ICD identifies the design solution to the interface requirement. ICDs are useful when separate organizations are developing design solutions to be adhered to at a particular interface. Interface Definition Document (IDD)-A unilateral document controlled by the end item provider, and provides the details of the interface for a design solution that is already established. IDD is sometimes referred to as a “one-sided ICD.”

4 2. [Marks 4-1/2] You are required to assess the technical risk in an Unmanned Aerial Vehicle (UAV) development using variable airfoil geometry by means of smart materials. a) [Mark 1/2] Which two "factors" determine the risk in a Risk Profile Matrix or Risk Map? b) [Mark 1] Which technical aspect is often taken to estimate the frequency with which a risk may occur? Can you give at least four typical entries on the ordinal scale determining this frequency? c) [Marks 1/2] Which kind of events may be considered by the other factor determining the risk? Can you give at least three typical entries in the ordinal scale used for that axis of the Risk Profile Matrix? d) [Marks 1] Draw a typical Risk Profile Matrix. Where are the items with the highest risk located? e) [Marks 1] Indicate how you are going to mitigate the risks. Which two typical risk mitigation approaches may be taken? What is the results of each of these approaches? f) [Mark 1/2] In case of the UAV: Which risk items or elements would you put as high risks where in the Risk Profile Matrix and why? Ans. a) Probability of occurrence and Severity of impact (or consequence) b) State of Technology (generally taken, not project or company specific) Typical entries on the ordinal scale ( any four of them ): Feasible in Theory, Working laboratory model, Based on existing non-flight engineering, Extrapolated from existing flight design, Proven flight design Note: When items are classified according to whether they have more or less of a characteristic, the scale used is referred to as an ordinal scale c) Severity of impact is expressed in terms of mission, cost or schedule. Any three of: Catastrophic, Critical, Marginal, Negligible. or Low, Moderate, High d) Here are the possible ten Risk Events: Risk Event 1 (R1). Man -Machine Interface Risk Event 2 (R2). Compliant Motion Control Risk Event 3 (R3). Open Loop Control Risk Event 4 (R4). Proximity Sensing

5 Risk Event 5 (R5). Manipulator Joints Risk Event 6 (R6). Manipulator Limbs Risk Event 7 (R7). EVA/ORU Mechanisms Risk Event 8 (R8). End Effector Risk Event 9 (R9). Retention Mechanism Risk Event 10 (R10). Long Space Exposure Risk Profile Matrix Feasible in Theory R4,R8 R1 R2 R10 Probability ------------> Working Laboratory Model R5 R7 R3,R9 Based on Existing Non-flight Engineering R6 Extrapolated from existing flight design Proven flight design Negligible Marginal Critical Catastrophic Consequence --------------------------> Highest risks are in the top hand corner.

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6 Note: For each technological aspect (such as Feasible in Theory, Working Laboratory Model), the Risk Profile Matrix can be made such as: Risk Profile Matrix (Feasible in Theory) Probability ------------> R4,R8 R1 R2 R10 Negligible Marginal Critical Catastrophic Consequence --------------------------> e) There are two ways to mitigate the risk: 1) Do (pre-) development: This results in increasing technology maturity. 2) Redesign, such that the risk item or element becomes less critical for system, mission or project The result is that the risk items or elements move to the bottom and/or to the left of the Risk map. g) High risk items for the UAV are the variable air foil and the smart materials. Probability of both items to be estimated somewhere between "feasible in theory" and "working laboratory model", severity of impact or consequence between "critical" and "catastrophic".

1 AER 817: Systems Engineering Solution to Quiz Date: Nov. 15, 2016 Marks: 10 Student Name: Student ID: Section No.: 1. [Marks 2] Answer the following questions: i) [Mark 1/2] Out of the total life cycle cost (LCC), 85% is locked in by the end of the following phase of the life cycle: a) Preliminary design b) Manufacturing c) Operations d) Disposal Ans. a) ii) [Mark 1/2] At the Conceptual design phase, which method is used to estimate the total life cycle cost of the project: a) Bottom-up method b) Analogous method c) Parametric method Ans. c) iii) [Mark 1/2] Which are the examples of Measures of Effectiveness (MOE) and Measures of Performance (MOP), respectively: a) Crew capacity and Schedule (e.g., development time, mission duration) b) Life-cycle cost and Power Consumption c) Specific impulse and Consumables required d) Specific impulse and Propellant type Ans. b)

2 iv) [Mark 1/2] The trade study process allows one to select the optimum solution based upon the given criteria/constraints Choose one a) True b) False Ans. True 2. [Marks 1-1/2 Each; Total Marks. 3] Answer the following questions: i) What is the difference between Bottom-up cost estimation and Parametric cost estimation? ii) What is the difference between measures of effectiveness and measures of performance? Ans. i) What is the difference between Bottom-up cost estimation and Parametric cost estimation? Ans. i) A) Bottom-up estimating (Bottom-up method) – Identify and specify lower level elements – Estimated cost of system is sum of these elements – Estimate is based on the cost of materials and labor to develop and produce each element, at the lowest level of the WBS possible. – Time consuming – Not appropriate for conceptual design phase; data not usually available until detailed design. B) Parametric estimating: – Estimate is based on equations called Cost Estimating Relationships (CERs) which express cost as a function of a design parameter (e.g., mass). – CERs can apply a complexity factor to account for technology changes. – CER usually accounts for hardware development and theoretical first unit cost (TFU). • For multiple units, the production cost equals the first unit cost times a learning curve factor. - Most appropriate for trade studies Advantages: Less time consuming than traditional bottoms-up estimates

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3 More effective in performing cost trades; what-if questions More consistent estimates Traceable to the class of aerospace systems for which the model is applicable Major limitations: Applicable only to the parametric range of historical data Lacking new technology factors so the CER must be adjusted for hardware using new technology Composed of different mix of “things” in the element to be costed from data used to derive the CER, thus rendering the CER inapplicable Usually not accurate enough for a proposal bid or Phases C-D-E ii) Measure of Performance (MOP) - A quantitative measure that, when met by the design solution, will help ensure that an MOE for a product or system will be satisfied. There are generally two or more measures of performance for each MOE.  Example measures of performance  Mass  Power consumption  Specific impulse  Consumables required  Propellant type Both MOEs and MOPs are system figures of merit; an MOE refers to the effectiveness of a solution and an MOP is a measure of a particular design.

4 3. [Marks 2-1/2] Determine a cost estimation relationship for unmanned planetary spacecraft with a dry mass between 100 and 1000 kg. The functional form of the CER is Total_Cost = A + B* Dry_Weight^C. The past data are available from NASA online spacecraft model for the Dry Mass of 100 kg and 1000 kg (see the table below). Calculate the appropriate parameters A, B, C that most closely approximate the past data and determine the CER costs for dry mass of 100 kg, 500 kg and 1000 kg. Ans. P=B*(W)^C C=log(192.38/704.34)/log(100/1000)= 0.5636 B=192.38/(100)^C=14.35 A=0; B=14.33; C=0.564 To calculate the CER cost: P= 192.28 x (W/100)^C The value of C, the exponent, indicates that there are significant economies of scale (EOS) in the design of unmanned planetary spacecraft. Dry Mass (kg) 100 500 1000 Total Cost ($M) $192.38 $704.34 CER Cost ($M) Dry Mass (kg) 100 500 1000 Total Cost ($M) $192.38 $704.34 CER Cost ($M) 192.38 476.56 704.34

5 4. [Marks 2-1/2] A space company has made 15 rocket engines at a total cost of $10 M and then decided to make a total of 25 rocket engines at a total cost of $15 M. If the company expects to sell in total 100 engines over the total life of the programme, what will be the total and average single unit cost of the 100 engines (use the learning curve formula Y = k x n ) . Ans: Y=k * x^N 10=k*(15)^N; 15=k*(25)^N (1) Log (15/10)=N*Log(25/15) (2) or, N=log(15/10)/log(25/15)=0.794 or, k=15/25^(0.794)=1.164 Total cost, Y=1.164 x (100)^0.794 = 45 Average= 45/100= 0.45 M per engine.

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