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Aerocapture Systems Analysis for a Neptune Mission Mary Kae Lockwood, Karl T

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Aerocapture Systems Analysis for a Neptune Mission Mary Kae Lockwood, Karl T NASA/TM-2006-214300 Aerocapture Systems Analysis for a Neptune Mission Mary Kae Lockwood, Karl T. Edquist, Brett R. Starr, Brian R. Hollis, and Glenn A. Hrinda NASA Langley Research Center, Hampton, Virginia Robert W. Bailey, Jeffery L. Hall, Thomas R. Spilker, Muriel A. Noca, N. O’Kongo, and Robert J. Haw Jet Propulsion Laboratory, Pasadena, California Carl G. Justus and Aleta L. Duvall Computer Sciences Corporation, Huntsville, Alabama Vernon W. Keller NASA Marshall Space Flight Center, Marshall Space Flight Center, Alabama James P. Masciarelli, David A. Hoffman, Jeremy R. Rea, Carlos H. Westhelle, Claude A. Graves NASA Johnson Space Center, Houston, Texas Naruhisa Takashima AMA, Inc., Hampton, Virginia Kenneth Sutton National Institute of Aerospace, Hampton, Virginia Joseph Olejniczak, Y. K. Chen, Michael J. Wright, and Bernard Laub NASA Ames Research Center, Moffett Field, California Dinesh Prabhu ELORET Corporation, Sunnyvale, California R. Eric Dyke Swales Aerospace, Hampton, Virginia Ramadas K. Prabhu Lockheed Martin Engineering and Sciences Company, Hampton, Virginia April 2006 The NASA STI Program Office . in Profile Since its founding, NASA has been dedi- • CONFERENCE PUBLICATION. Collected cated to the advancement of aeronautics and space papers from scientific and technical confer- science. The NASA Scientific and Technical In- ences, symposia, seminars, or other meet- formation (STI) Program Office plays a key part in ings sponsored or co-sponsored by NASA. helping NASA maintain this important role. • SPECIAL PUBLICATION. Scientific, tech- nical, or historical information from NASA The NASA STI Program Office is operated by programs, projects, and missions, often con- Langley Research Center, the lead center for cerned with subjects having substantial pub- NASA’s scientific and technical information. The lic interest. NASA STI Program Office provides access to the NASA STI Database, the largest collection of • TECHNICAL TRANSLATION. English- aeronautical and space science STI in the world. language translations of foreign scientific The Program Office is also NASA’s institutional and technical material pertinent to NASA’s mechanism for disseminating the results of its re- mission. search and development activities. These results are published by NASA in the NASA STI Report Specialized services that complement the STI Series, which includes the following report types: Program Office’s diverse offerings include creat- ing custom thesauri, building customized data- • TECHNICAL PUBLICATION. Reports of bases, organizing and publishing research results completed research or a major significant ... even providing videos. phase of research that present the results of NASA programs and include extensive data For more information about the NASA STI Pro- or theoretical analysis. Includes compila- gram Office, see the following: tions of significant scientific and technical data and information deemed to be of con- • Access the NASA STI Program Home Page tinuing reference value. NASA counterpart at http://www.sti.nasa.gov of peer-reviewed formal professional papers, but having less stringent limitations on • E-mail your question via the Internet to manuscript length and extent of graphic [email protected] presentations. • Fax your question to the NASA STI Help • TECHNICAL MEMORANDUM. Scientific Desk at (301) 621-0134 and technical findings that are preliminary or of specialized interest, e.g., quick release • Phone the NASA STI Help Desk at reports, working papers, and bibliographies (301) 621-0390 that contain minimal annotation. Does not contain extensive analysis. • Write to: NASA STI Help Desk • CONTRACTOR REPORT. Scientific and NASA Center for AeroSpace Information technical findings by NASA-sponsored con- 7121 Standard Drive tractors and grantees. Hanover, MD 21076-1320 NASA/TM-2006-214300 Aerocapture Systems Analysis for a Neptune Mission Mary Kae Lockwood, Karl T. Edquist, Brett R. Starr, Brian R. Hollis, and Glenn A. Hrinda NASA Langley Research Center, Hampton, Virginia Robert W. Bailey, Jeffery L. Hall, Thomas R. Spilker, Muriel A. Noca, N. O’Kongo, and Robert J. Haw Jet Propulsion Laboratory, Pasadena, California Carl G. Justus and Aleta L. Duvall Computer Sciences Corporation, Huntsville, Alabama Vernon W. Keller NASA Marshall Space Flight Center, Marshall Space Flight Center, Alabama James P. Masciarelli, David A. Hoffman, Jeremy R. Rea, Carlos H. Westhelle, Claude A. Graves NASA Johnson Space Center, Houston, Texas Naruhisa Takashima AMA, Inc., Hampton, Virginia Kenneth Sutton National Institute of Aerospace, Hampton, Virginia Joseph Olejniczak, Y. K. Chen, Michael J. Wright, and Bernard Laub NASA Ames Research Center, Moffett Field, California Dinesh Prabhu ELORET Corporation, Sunnyvale, California R. Eric Dyke Swales Aerospace, Hampton, Virginia Ramadas K. Prabhu Lockheed Martin Engineering and Sciences Company, Hampton, Virginia National Aeronautics and Space Administration Langley Research Center Hampton, Virginia 23681-2199 April 2006 Available from: NASA Center for AeroSpace Information (CASI) National Technical Institute Service (NTIS) 7121 Standard Drive 5285 Port Royal Road Hanover, MD 21076-1320 Springfield, VA 22161-2171 (301) 621-0390 (703) 605-6000 TABLE OF CONTENTS Neptune Aerocapture Systems Analysis ……………………………………… 1 Neptune Aerocapture Mission and Spacecraft Design Overview ……………………………………… 17 Mission Trades for Aerocapture at Neptune ……………………………………… 29 Configuration, Aerodynamics, and Stability Analysis for a Neptune ……………………………………… 45 Aerocapture Orbiter Aerocapture Navigation at Neptune ……………………………………… 57 Atmospheric Models for Aerocapture ……………………………………… 74 Atmospheric Models for Aerocapture Systems Studies ……………………………………… 80 Aerocapture Performance Analysis for a Neptune-Triton Exploration ……………………………………… 87 Mission Aerocapture Guidance Performance for the Neptune Orbiter ……………………………………… 98 Preliminary Convective-Radiative Heating Environments for a ……………………………………… 107 Neptune Aerocapture Mission TPS Challenges for Neptune Aerocapture ……………………………………… 119 Structural Design for a Neptune Aerocapture Mission ……………………………………… 130 iii NEPTUNE AEROCAPTURE SYSTEMS ANALYSIS Mary Kae Lockwood NASA Langley Research Center, Hampton, Virginia, 23681-2199 A Neptune Aerocapture Systems Analysis is completed to determine the feasibility, bene- fit and risk of an aeroshell aerocapture system for Neptune and to identify technology gaps and technology performance goals. The high fidelity systems analysis is completed by a five center NASA team and includes the following disciplines and analyses: science; mission de- sign; aeroshell configuration screening and definition; interplanetary navigation analyses; atmosphere modeling; computational fluid dynamics for aerodynamic performance and da- tabase definition; initial stability analyses; guidance development; atmospheric flight simula- tion; computational fluid dynamics and radiation analyses for aeroheating environment definition; thermal protection system design, concepts and sizing; mass properties; struc- tures; spacecraft design and packaging; and mass sensitivities. Results show that aerocapture can deliver 1.4 times more mass to Neptune orbit than an all-propulsive system for the same launch vehicle. In addition aerocapture results in a 3-4 year reduction in trip time compared to all-propulsive systems. Aerocapture is feasible and performance is adequate for the Neptune aerocapture mission. Monte Carlo simulation re- sults show 100% successful capture for all cases including conservative assumptions on at- mosphere and navigation. Enabling technologies for this mission include TPS manufactur- ing; and aerothermodynamic methods and validation for determining coupled 3-D convec- tion, radiation and ablation aeroheating rates and loads, and the effects on surface recession. SYMBOLS/NOMENCLATURE A = Area (m2) CN = Normal Force Coefficient αtrim = Trim Angle of Attack D = Drag CA = Axial Force Coefficient GA = Gravity Assist CBE = Current Best Estimate L = Lift CD = Coefficient of Drag L/D = Lift-to-Drag ratio CFD = Computational Fluid Dynamics M/CDA = Ballistic Coefficient (kg/m2) CG, cg = Center of Gravity SEP = Solar Electric Propulsion CL = Coefficient of Lift TPS = Thermal Protection System INTRODUCTION EROCAPTURE significantly increases the mass that A can be delivered in orbit at a destination with an atmos- phere compared to an all-propulsive vehicle at the same des- tination with the same launch vehicle. Aerocapture utilizes aerodynamic forces on a vehicle during a single pass through a destinations atmosphere to capture into orbit about that destination, instead of a large propulsive delta V maneuver. An aerocapture flight profile schematic showing the primary aerocapture event sequence is shown in Fig. 1. 1 Aerocapture at Neptune is characterized by high entry velocities (28-30 km/sec inertial) into a H2 He atmosphere, and capture into a high energy science orbit enabling Tritan flybys. Table 1 provides a comparison of the Neptune aero- capture reference mission, described in this paper, to a repre- sentative Mars aerocapture mission, and a Titan aerocapture Figure 1. Aerocapture trajectory schematic. reference mission1. The high entry velocities at Neptune compared to Titan and Mars result in significantly more severe environments at Neptune, including both aeroheating and g’s. The high energy science orbit for Neptune 1 compared to the reference Titan and Mars missions, requires a significantly greater vehicle lift to drag ratio to pro-
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