NASA Cost and Schedule Symposium August 13-15, 2019 • Houston, TX System Integration Schedule Estimating Relationships (SERs) Presented by: Marc Greenberg Strategic Investment Division (SID) National Aeronautics and Space Administration Outline • Task Objectives • Background • Schedule Data from SMART • Methodology – Equation 1: Y = 0.3617 X -0.568 – Equations 2a, 2b, 3a and 3b – “Knee in the Curve” for Equation 1 • Example for notional project – Apply equations 2a, 2b, 3a and 3b – Sensitivity analysis • Conclusions and Future Work Slide 2 Task Objectives a • Estimate “ideal” (Design Sched.)/(Sys. I&T Sched.) ratio • Create schedule estimating relationships (SERs) to predict the following durations: – SRR (System Readiness Review) to CDR (Critical Design Review) – SIR (System Integration Review) to LRD (Launch Readiness Date) – SRR to LRD (i.e., total schedule less time from ATP b to SRR) • Demonstrate how these SERs could be used in practice • Discuss use of sensitivity analysis. (a) Schedule data was readily available so no data collection effort was required. (b) ATP: Authority to Proceed Slide 3 Background: Milestones from SRR to LRD Phase A-B Phase D-E System Level SRR LRD System Level Design Requirements Subsystems Element Item Level SIR Component Design Requirements PDR CDR Phase C All Design Requirements Complete Major Milestones: SRR: Systems Readiness Review PDR: Preliminary Design Review CDR: Critical Design Review SIR: System Integration Review LRD: Launch Readiness Date Slide 4 Schedule Data from SMART NASA’s Schedule Management and Relationship Tool (SMART) provided schedule data from 55 science missions. Values in Months. Mission SRR-PDR PDR-CDR CDR-SIR SIR-LRD SRR-LRD Mission SRR-PDR PDR-CDR CDR-SIR SIR-LRD SRR-LRD CONTOUR 8 11 14 5 38 SWAS 31 10 10 52 103 Dawn 6 8 7 33 54 WIRE 23 0 17 18 58 Deep Impact 10 11 16 20 57 WISE 7 23 17 13 60 Deep Space 1 3 9 11 15 38 NuSTAR 11 8 12 17 48 Galileo 9 33 15 82 139 OCO 12 25 20 11 68 InSight 28 9 9 39 85 ACE 12 12 19 16 59 Juno 30 11 12 16 69 ACTS 10 24 37 27 98 MAP 8 5 35 14 62 AIM 8 10 0 30 48 MAVEN 11 12 12 17 52 Aqua 5 14 1 47 67 MER-A 3 14 3 16 36 Aura 5 14 13 34 66 MER-B 3 14 4 15 36 Calipso 8 18 11 26 63 MESSENGER 13 10 10 19 52 CHIPSAT 12 8 14 8 42 MRO 6 10 11 16 43 DART 5 4 7 25 41 MSL 6 12 9 46 73 EO-1 8 10 5 21 44 OSIRIS-REX 10 13 11 19 53 FAST 14 10 15 33 72 Phoenix 11 8 5 16 40 Glory 12 11 19 38 80 Stardust 6 9 7 13 35 IMAGE 9 5 20 12 46 Chandra X-Ray 23 15 20 22 80 IRIS 3 7 18 13 41 COBE 15 25 35 15 90 LANDSAT-7 12 13 16 27 68 FGST (GLAST) 33 15 23 22 93 LANDSAT-8 14 10 18 14 56 GALEX 3 8 26 20 57 NPP 35 9 62 36 142 IBEX 4 8 13 13 38 OSTM/Jason-2 10 44 7 12 73 Kepler 12 24 19 10 65 Aquarius 12 36 11 25 84 RHESSI 7 4 13 26 50 MMS 20 13 25 31 89 SAMPEX 3 10 14 11 38 SMAP 22 9 9 22 62 SDO 11 13 0 59 83 TRACE 2 1 16 13 32 Spitzer 7 12 41 19 79 VABP (RBSP) 8 14 11 23 56 STEREO 19 14 18 26 77 Slide 5 Methodology: Equation 1: Y = 0.3617 X -0.568 Relative Sys I&T Schedule vs. "Design-to-Sys I&T" Schedule Ratio (SIR to LRD / SRR to LRD) versus (SRR to CDR / SIR to LRD) 0.90 As (SRR to CDR) / (SIR to LRD) increases, (SIR to LRD) / (SRR to LRD) decreases. 0.80 i.e., As relative design schedule increases, relative sys I&T schedule decreases. 0.70 Y: (SIR to CDR) ~ Sys I&T vs. Total Sched. 0.60 (SRR to LRD) Potentially insufficient design schedule X: (SRR to CDR) ~ Design vs. Sys I&T 0.50 (SIR to LRD) 0.40 0.30 Y = 0.3617 X -0.568 2 0.20 R = 0.79 (MUPE) 0.10 Sys I&T Schedule as % of Project Schedule = (SIR to LRD LRD / LRD) (SRR ) to Schedule (SIR to = as %I&TSchedule of Project Sys 0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 Design Schedule relative to Sys I&T Schedule = (SRR to CDR) / (SIR to LRD) Slide 6 Methodology: Equations 2a, 2b, 3a and 3b (SRR to CDR) Note: Schedule data in Months; Sample size = 55 (SIR to LRD) Eq. 2a: SRR to CDR = 0.3060 * SRR to LRD 1.041 Design vs Sys I&T 0.4306 Adj-R2 (MUPE) = 0.86; Avg. = 24.5 mo. SE = 4.3 mo.; MAD = 13.4% Rearrange Equation 2a to create Equation 2b … Eq. 2b: SRR to LRD = 3.1196 * SRR to CDR 0.9607 Design vs Sys I&T -0.4137 Eq. 3a: SIR to LRD = 0.3060 * SRR to LRD 1.041 Design vs Sys I&T -0.5694 Adj-R2 (MUPE) = 0.91; Avg. = 23.4 mo. SE = 4.5 mo.; MAD = 13.4% Rearrange Equation 3a to create Equation 3b … Eq. 3b: SRR to LRD = 3.1196 * SIR to LRD 0.9607 Design vs Sys I&T 0.5470 Q: How can we use each SER if we must know not one but up to three independent variables? A: Simplify “Design vs Sys I&T” input! Slide 7 Methodology: “Knee in the Curve” for Eq. 1 Relative Sys I&T Schedule vs. "Design-to-Sys I&T" Schedule Ratio (SIR to LRD / SRR to LRD) versus (SRR to CDR / SIR to LRD) 0.90 1. Connect endpoints of Y = 0.3617 X -0.568 0.80 2. Calculate Slope of straight line = -0.159 0.70 Knee in the curve: Point on curve where distance between line & curve is greatest. Must find the 0.60 point tangent to curve parallel to straight line. 0.50 3. Derivative of Y = 0.3617 X -0.568 -1.568 0.40 = Straight line = -0.2055 X 0.30 0.20 0.10 4. Given Y’ = -0.2055 X -1.568 … find X where slope = -0.159 Sys I&T Schedule as % of Project Schedule = (SIR to LRD LRD / LRD) (SRR ) to Schedule (SIR to = as %I&TSchedule of Project Sys 0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 X= 1.175Design Schedule relative to Sys I&T Schedule = (SRR to CDR) / (SIR to LRD) Slide 8 Methodology: “Knee in the Curve” for Eq. 1 Calculation of "Knee in the Curve" for: Relative Sys I&T Schedule vs. "Design-to-Sys I&T" Schedule Ratio 0.90 Knee in the curve: That point on the curve 0.80 where distance between the “connector” line and curve is greatest … 0.70 … that point on the curve is (1.175, 0.330) X = “Design vs Sys I&T” = 1.175 0.60 “Design vs. Sys I&T” = (SRR to CDR) (SIR to LRD) 0.50 For all SERs, we assume an “ideal” 0.40 Design vs Sys I&T Y = 0.330 input = 1.175 0.30 0.20 X = 1.175 y = 0.3617x-0.568 0.10 Sys I&T Schedule as % of Project Schedule = (SIR to LRD) LRD) LRD) (SRR / to Scheduleto (SIR = % as ScheduleI&Tof Project Sys 0.00 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 Design Schedule relative to Sys I&T Schedule = (SRR to CDR) / (SIR to LRD) Slide 9 Example for Notional Project: Equation 2a Eq. 2a: SRR to CDR = 0.3060 * SRR to LRD 1.041 Design vs Sys I&T 0.4306 • Input 1: SRR to LRD = 60 mos. (e.g., constraint for planetary mission “M”) • Input 2: Design vs Sys I&T = 1.175 (“knee-in-the-curve” value) SRR to CDR = 0.3060 * 60 1.041 1.175 0.4306 = 23.3 mos. 1.175 = SRR to CDR so … SIR to LRD = 23.3 = 19.8 mos. SIR to LRD 1.175 CDR to SIR = (SRR to LRD) – (SRR to CDR) – (SIR to LRD) = 16.9 mos. 60 23.3 19.8 SRR to LRD (Given) = 60 months We can now rearrange SRR to CDR = 23.3 CDR to SIR = 16.9 SIR to LRD = 19.8 Eq. 2a to form Eq. 2b 39% 28% 33% where Y = SRR to LRD. Estimates of "SRR to CDR", "CDR to SIR" and "SIR to LRD" (in months) 0 10 20 30 40 50 60 Slide 10 Example for Notional Project: Equation 2b Eq. 2b: SRR to LRD = 3.1196 * SRR to CDR 0.9607 Design vs Sys I&T -0.4137 • Input 1: SRR to CDR = 23.3 mos. (e.g., in-family for planetary mission “M”) • Input 2: Design vs Sys I&T = 1.175 (“knee-in-the-curve” value) SRR to LRD = 3.1196 * 23.3 0.9607 1.175 -0.4137 = 60.0 mos. 1.175 = SRR to CDR so … SIR to LRD = 23.3 = 19.8 mos.