https://ntrs.nasa.gov/search.jsp?R=20140009378 2019-08-31T20:33:41+00:00Z Applied Aeroscience and CFD Branch Overview Gerald J. LeBeau Dr. Benjamin S. Kirk Applied Aeroscience and CFD Branch Engineering Directorate Houston, Texas USA 1 Lyndon B. Johnson Space Center Principal Mission: Human Spaceflight International Space Station MPCV Orion Commercial Crew Mission Control Astronauts 2 The Future of Human Space Exploration NASA’s Building Blocks to Mars Expanding capabilities by visiting an asteroid in a Lunar distant retrograde orbit U.S. companies provide affordable access to low Earth orbit Exploring Mars and other deep space Learning the destinations fundamentals aboard the International Traveling beyond low Earth Space Station orbit with the Space Launch System rocket and Orion crew capsule Missions: 6 to 12 months Missions: 1 month up to 12 months Missions: 2 to 3 years Return: hours Return: days Return: months 3 Earth Reliant Proving Ground Earth Independent Aeroscience Technical Competencies (1) Aerodynamic Characterization (2) Aerothermodynamic Heating (3) Rarefied Gas Dynamics (4) Decelerator (Parachute) Systems Ground Testing Modeling and Simulation Flight Testing 5 Principal JSC Initiatives & Aeroscience Support 1. Operate the International Space Station • Aerodynamic & aerothermodynamic response for rarefied flows • Plume modeling for visiting vehicles • ISS end-of-life disposal 2. Develop the Multipurpose Crew Vehicle Orion • Develop aerodynamic & aeroheating databases • Support development of the parachute recovery system 3. Enable Commercial Access to Space • Develop system requirements and assess design compliance • Perform IV&V of partner aerosciences products • Support reimbursable activities to commercial partners 6 International Space Station Operations 7 Commercial Crew Program 8 NASA’s Exploration Architecture ORION | SPACE LAUNCH SYSTEM 9 Capability Comparison Medium/Intermediate Heavy Super Heavy Retired 300’ 200’ Retired 100’ ULA SpaceX ULA NASA NASA NASA NASA NASA 160 Atlas V 551 Falcon 9 Delta IV H Space Shuttle Saturn V 70 t 105 t 130 t 1600 140 1400 Payload (m3) Volume Payload 120 1200 Mass (mT) Volume (m3) 100 1000 80 800 60 600 40 400 Payload (mT) Mass Payload 20 …. 200 0 0 As of November 8, 2012 Orion Aerosciences JSC Responsible Flight Regimes Mach 25 Entry Heating Phase Direct Entry On-Orbit Service Module Jettison Hypersonic Abort Plumes Environment Skip Entry LAT Nominal Jettison Atmospheric Mach ~7.5, ~200k ft alt 2nd Stage Abort Entry Environment Plume Heating Service Module LAT Sep Jettison 1st Stage Abort Turn-around maneuver Forward Heat Shield Sep Main Chutes Ascent Abort PadParachute Abort System Deploy Mach Separation ~0.1 Environment Pad Abort Heat Shield Sep 11 The Orion Spacecraft Crew Module Human habitat from launch through landing and recovery. Launch Abort System Provides crew escape during launch pad and ascent emergencies. Service Module Power, propulsion and environmental control support to the Crew Module. Provided by the European Space Agency. Orion Pad Abort Test 13 Entry Aerothermodynamic Modeling Orion Exploration Flight Test 1 Upcoming December 2014 15 Parachute Recovery System Development Extraction from a C-17 Smart Separation & PTV Programmer Static Line Deployment. Deploy 2 programmer chutes after separation Release programmers and mortar fire 3 FBCPs FBC Jettison and drogue mortar fire Crewed 3 Pilot chutes are mortar deployed. flight- These deploy the main parachutes. CPSS falls under like two Extraction Parachutes and 17 then 2 main Technical Competencies Aerodynamics Aerothermodynamics Rarefied Gas Dynamics Decelerator Systems 18 Aerodynamics Discipline Overview • Provide comprehensive aerodynamic induced environments from ascent through entry and landing to Trajectory and Structural analysts. • Products include – Ascent, entry and abort aerodynamics, external pressure distributions, protuberance air loads, stability derivatives, acoustics/overpressure, venting, plume effects, prelaunch wind effects and wake environments for parachute analysis. • Tools – Computational Fluid Dynamics codes – Wind tunnels from subsonic through hypersonic regimes. – Flight tests 19 Aerodynamics Discipline Overview 20 Aerodynamics Challenge: Launch Acoustics • Accurate, efficient prediction of unsteady transonic environments CFD requires small time steps to accurately capture physics. Wind tunnel testing requires ≈ 5 seconds of physical time to achieve statistical convergence. AIAA 2011-3504 21 control system inactive). Without an active closed-looped flight control system, the dynamic stability characteristics of the LAV will cause the vehicle to either tumble from heatshield-forward free- flight or exhibit a coning motion. Figure 2 shows the concept of operations for a launch abort. At abort initiation, the abort motor fires, causing the LAV to separate from the launch 4 0 5 3 vehicle. There is a period of - 1 1 0 tower-forward flight, 2 . 6 / 4 followed by a reorientation 1 5 2 . phase during which the LAV 0 1 : I rotates into heatshield- O Figure 1. Illustration showing the various parts of the Orion spacecraft. D | forward flight. An active g r o . control system, via an attitude control motor at the top of the LAV, is used for stability and control. There is a a i a . c sufficient vehicle angular rate during the reorientation maneuver such that the dynamic aerodynamics produce a r a / / : significant contribution to the overall aerodynamics. After reorientation, aerodynamic damping plays a significant p t t h Aerodynamics Challenge: | role in the number of command overshoots for abort regimes where dynamic pressure is high. For the CM there are 4 1 0 periods of free-flight between LAT jettison and drogue inflation and between drogue release and main chute 2 , 7 Dynamic Stability 4 0 1 inflation, where its dynamic instability can significantly affect the trajectory of the CM. Also, wit5 h sufficient body 3 - h 1 c 1 r 0 2 a angular rates at drogue inflation, the CM dynamic aerodynamics can contribute to unacceptabl. e motions while 6 / 4 M 1 5 n 2 flying under the drogues. 0 o 1 • Prediction of dynamic stability: characteristics using I R O E D The importance of accurately determining the dynamic aerodynamic instabilities of blunt-body vehicles has been | T g r o N 1 . a a E evident since at least the Mercury programCFD. The onApol lao pbluffrogram bodydevoted cwithonsider ajetsble ri e sinour ccrosses toward flow. a . C c r 2 a Figure 8. Orion 8.63%-scale Crew Module mounted to the traverse sting for forced oscillation and free-to- / E / : characterizing the dynamic stability of the Command Module and Launch Escape Vehicle . Sincep the Orion CM is C t t oscillate testing in the NASA LaRC Transonic Dynamics Tunnel. h A | 4 P 1 very similar to the Apollo 0 S 2 To address concerns from Test 8-CD, the next two entries (18-CD and 27-AD) into the TDT used a newly , 7 N 1 h designed forced oscillation system. This new apparatus was designed to mate to an existing hydraulically driven O Command Module, the c r S a oscillation system through a clutch and brake mechanism. This apparatus mounts the model to a sting that traverses M N n o H dynamic aerodynamic tests the tunnel cross-section (see Figs. 8 and 9). R E O T J The sting mates to the model from the sides so that the model can be oscillated about the flight-derived cg. With N from the Apollo project E A C the clutch-brake system S E C A the model could be tested provided valuable insight A P N S in three modes – static N y O b S into damping force and moment, forced N d H e oscillation, and free-to- O d J a characteristics of the Orion A oscillate - without needing S o l A n N a separate tunnel entry or CM. Some of the y w b d o time to switch between e d D a o modes. The new rig differences between the l n w o allowed for measuring data two vehicles are the Outer D over the full 360° angle- Mold Line (OML), of-attack range without a need for personnel to enter moments of inertias, and the tunnel. The hydraulic oscillation system is fully center of gravity (cg) programmable, allowing for any motion within the location. Because each of torque limits of the drive these differences can affect Figure 9. Orion 11%-scale ALAS Launch Abort Vehicle mounted to the system. Although any traverse sting for static force & moment, forced oscillation and free- arbitrary motion was dynamic stability, new to-oscillate testing in the NASA LaRC Transonic Dynamics Tunnel. possible, only sinusoidal tests were required. Also, AIAA 2011-8 3504 advancements in test American Institute of Aeronautics and Astronautics Figure 2. Illustration of the concept of operations for an abort from the techniques since the launch vehicle. 22 Apollo program make 3 American Institute of Aeronautics and Astronautics Aerothermodynamics Discipline Overview • Goal is to provide heating environments to all external spacecraft components for all flight regimes – Components: acreage, steps/gaps, seals, penetrations, protuberances, reaction control systems – Flight regimes: ascent, exo-atmospheric, entry • Current customers include Orion, Commercial Crew, and technology development projects – Orion: Leads agency wide team that develops aerothermodynamic environment database, provides technical authority oversight, provides mission support (historically provided mission support and damage assessment for Orbiter) – Commercial Crew: Supports all commercial partners with both inline product development and technical authority oversight – Technology development: Leads development