Transition Impacts for Converting from NAFCOM07 to NAFCOM08 for HLV Estimates

1. Transition Impacts for Converting from NAFCOM07 to NAFCOM08 for HLV Estimates Billy Carson George Culver Melek Ferrara Teresa Brown

2. Analysis Process • Identify LV missions to incorporate, obtain consensus • Extract historical subsystem data and actual costs from NAFCOM database for identified missions • Model these missions in NAFCOM07 to estimate subsystem costs • Deflate to FY06 to match NAFCOM08 outputs • Model same missions in NAFCOM08 with identical technical inputs to estimate subsystem costs • Collect all subsystem data in summary database • Aggregate cost to system level & report results

3. Ground Rules & Assumptions • All costs reported in FY06$M • Used NASA HQ New Start inflation tables for all cost escalations. • DDT&E and TFU are estimated for all launch vehicles selected for this study. Estimates for historical missions are then compared to actual costs from those missions. • Estimates derived using MV Subsystem CERs, with exception of some component estimates for Shuttle SRM and Ares I RSRM. • Standard error is calculated as: Square Root of the sum of squares of the differences between estimated and actual divided by degrees of freedom.

4. Before We Get Started…. • For the NAFCOM07 users in the room – here’s a quick primer on what has changed between the two versions: • NAFCOM is now developed in the .NET 2.0 platform. This conversion from Visual Basic 6.0 improves the model’s performance. • The NAFCOM databases have been converted from Access to SQL to improve performance. • All multi-variable CER equations were reviewed and modified to improve goodness-of-fit statistics. • A significant number of new data points was also added to the CER data sets. • Seventeen new component-level CERs were incorporated into this version. • New interface for risk analysis outputs incorporated (charts, statistics, etc). • New statistics integrated into historical database.

5. Before We Get Started…. • New multi-variable CERs • First revision since NAFCOM04 • Revisited cost drivers • Investigated use of alternate CER development methods and algorithms. • Significant number of new data points were added to the CER data set. • Varied by subsystem, but ranged as high as 20. • TMI was assessed for individual NAFCOM missions and other spacecraft • Once Technology Maturity values were assessed for each technology, subsystem-level values were added as independent variables to the multivariate CERs for AD&C and CC&DH. • These changes improved the CER goodness-of-fit measures substantially. • Assumed slope CERs • Re-calculated the b-values for each CER using log-transformed OLS • Calculated new a-values for each CER

6. Launch Vehicle Comparisons • S-IVB • S-II • S-IC • Shuttle Orbiter • SRM • SRB • Atlas V Common Core Booster (CCB) • Atlas V Upper Stage (US) • Ares I First Stage (FS) • Ares I Upper Stage (US) • Heavy Lift Propulsion Technology (HLPT) Concept Launch Vehicles • Atlas Phase 3 • 103.05.02 • 117.18.02 • 118.02.00 • 119.02.00

7. Percent Different from ActualDDT&E *Negative value indicates estimate is less than actual.

8. DDT&E Comparison

9. DDT&E Comparison (continued)

11. Percent Different from ActualTFU *Negative value indicates estimate is less than actual.

12. TFU Comparison

14. Standard Percent Error • Standard percent error is calculated as: Square Root of the sum of squares of the percent difference between estimated and actual divided by degrees of freedom. • Both show favorable reductions in percent error for the concepts evaluated.

15. Conclusions • In Majority of Launch Vehicles, NAFCOM08 provided an Closer Estimate to the Actual Cost • For DDT&E only S-IVB and Atlas V CBBhad lower total percent differences in NAFCOM07 • For TFU, where actuals existed for comparison, only S-II and Shuttle Orbiter had lower percent differences in NAFCOM07 • Standard Error calculation for DDT&E is lower for NAFCOM 08 compared to NAFCOM 07 with this mission set

16. Back-up charts

17. Significant Changes Multi-Variable CERs CC&DH • TMI Input Added • Lander/Probe Input Added • Mission Type Input Removed ECLS • Thermal Component Input Added Electrical Power • Power Regulation Input Removed Landing • Multi-Variable CER Removed GN&C/Attitude Control • TMI Input Added • Autonomy Input Removed Reaction Control • Design Life Input Added • ISP Input Removed • Propellant Weight Input Removed • Propellant Input Removed Solid Rocket Motor • Launch Vehicle Input Added • Upper Stage Only Input Removed Structures • Primarily Aluminum Input Added • Deployed Input reworked into a Significant Deployables Yes/No Input. • Structural Efficiency Input Removed Thermal • State of the Art Input Added • Insulation Coatings Only Added • External Cryogenic Storage Tank Input Removed Thrust Vector Control • Number of Engines Input Added • Solid Rocket Motor Input Added NAFCOM 07 estimates converted to NAFCOM08 have new inputs set to the first choice by default.

18. Significant Changes cont. Weight Based CERs • Previous versions of NAFCOM used straight average for calculation of the a-value when multiple analogous datapoints were chosen. NAFCOM08 uses the geometric mean to calculate the a-value of the selected datapoints for the weight based CERs. This typically results in lower costs. • The user may now select separate analogies for each element of system integration. If you are selecting datapoints at the parent level of system integration and would like those selections to be used for all children–make sure you select the “Use currently selected datapoints for all elements of integration” checkbox. The default setting is for that checkbox is checked.