Optimization of a Reusable Rocket-Powered, VTVL Launch System: A Case Study of the Falcon 9-R 04 August 2014 John E. Bradford, Ph.D. President, Principal Engineer [email protected] | 1+770.379.8007 Brad St. Germain, Ph.D. Director, Advanced Concepts Group [email protected] | 1+770.379.8010 Kevin Feld Sr. Aerospace Engineer [email protected] | 1+770.379.8005 DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 1 Case Study . SpaceWorks was interested in examining the performance of the SpaceX Falcon 9-R system that is currently under development as a test case for the VTVL simulation . System closure simulation created in PHX ModelCenter™ allowed us to quickly reverse engineer the baseline Falcon 9 system and anchor the models to various pieces of public information . Gross mass and propellant loads . Engine performance specifications . Vehicle dimensions and fairing geometry . Mission launch profile (times, altitudes, velocities) . Statements made by SpaceX employees . Anticipate that as additional details on the F-9R performance are released, the model can be further validated and/or calibrated . Using the reference closure model, we were then able to assess the impact of reusability on the system and explore various sensitivities DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 2 Reference Concept . Non-proprietary Falcon 9 v1.1 system . Public data sources and engineering models calibrated for: . Geometry . Propellant loads . Propulsion . Aerodynamics . Trajectory . Fairing . Assumed flight constraints common for expendable launch systems Parameter Value Gross Liftoff Weight 1,115,200 lbm Upperstage Gross Weight 246,150 lbm Total Height 224 feet Diameter 12 feet Liftoff T/W 1.2 Reported Payload to LEO 28,990 lbm Image Credit: SpaceX DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 3 VTVL Assessment . Examined downrange booster recovery as well as RTLS option . Fixed vehicle size and mass, per the reference concept . Booster stage mass model includes landing system/legs . Recovery/Landing Requirements: . Vertical orientation (gamma -90 deg) at touchdown . Velocity @ touchdown < 20.0 fps . Single-engine operation for terminal maneuver . 3 engines operable for any initial boostback burn . Max. heat rate constraint of 15 BTU/ft2-s (assumed) . Optimization: Maximum upperstage payload mass that can be delivered to LEO for either the expendable booster case, booster with RTLS recovery, or booster with downrange landing DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 4 VTVL Concept Simulation Model . Created a multi-disciplinary simulation using Phoenix Integration’s ModelCenter™ engineering environment DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 5 Results : FlightSight™ Images Downrange Landing Booster Parameter Value Flight Time 390 sec Final Downrange Distance 156 nmi Max Downrange Distance 156 nmi Mach Number @ Staging 7.1 Altitude @ Staging 201,500 feet Peak Altitude 271,500 feet RTLS Maneuver Booster Parameter Value Flight Time 480 sec Final Downrange Distance ~0 nmi Max Downrange Distance 57 nmi Mach Number @ Staging 6.0 Altitude @ Staging 187,000 feet Peak Altitude 423,500 feet DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 6 Results : Trajectory Details Altitude vs. Time Mach Number vs. Time DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 7 Results : Trajectory Details(2) Downrange vs. Time Thrust vs. Time DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 8 Results: Performance Summary Booster Parameter Expendable Downrange RTLS Landing Propellant Used 0 lbm 44,350 lbm 84,680 lbm Recovery Propellant (% Booster Total Prop) 0.0 % 5.5 % 10.5 % Staging Mach Number 8.4 7.1 6.0 Videal Post-Staging 0 fps 5,400 fps 8,900 fps DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 9 Trade Study . Examined impact of removing max. heat rate constraint for recovery trajectories . RTLS trajectory was not impacted (inactive constraint), but the downrange case was impacted significantly DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 10 Conclusions DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 11 Summary . SpaceWorks has developed a system closure and optimization model for VTVL concepts . Simulation capability was tested using performance data for the SpaceX Falcon 9 v1.1 . PHX ModelCenter implementation enabled rapid trade studies and system sensitivity analyses . For case study, the performance impacts of two different first stage propulsive recovery options (downrange landing and RTLS) were evaluated and compared to non-recoverable options . Downrange propulsive landing results in a ~20% drop in payload performance compared to expendable booster mission; RTLS results in a ~40% drop in payload compared to expendable (no recovery) approach . Regarding the cost savings due to reusability, gains must outweigh performance reductions . Expendable upperstage, estimated at ~$20M, establishes floor for $/lbm-payload . Must also include booster propellant and refurbishment costs (at a minimum) . Cost savings may not be as significant as some claim, but appears to still be a net gain . Progress is being made, but we need to continue push for full reusability on these systems DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 12 SPACEWORKS ENTERPRISES, INC. (SEI) | www.sei.aero | [email protected] 1040 Crown Pointe Parkway, Suite 950 | Atlanta, GA 30338 USA | 1+770-379-8000 DISTRIBUTION STATEMENT A UNLIMITED. APPROVED FOR PUBLIC RELEASE. 13 .