2006-2007 - Kennedy Space Center Technology Transfer Office

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Trajectory Model of Lunar Dust ParticlesThe goal of this work was to predict the trajectories of blowing lunar regolith (soil)Site Preparation particles when a spacecraft lands on or launches from the Moon. The blown regolith isand Excavation known to travel at very high velocity and to damage any hardware located nearby on theMoon. It is important to understand the trajectories so we can develop technologies tomitigate the blast effects for the launch and landing zones at a lunar outpost. A mathematical modelwas implemented in software to predict the trajectory of a single spherical mass acted on by the gasjet from the nozzle of a lunar lander. As initial conditions, the trajectory calculation uses the particlediameter D and initial position of the particle r 0= (x 0, y 0, z 0), where the vertical direction x is positiveup and equal to zero at the surface. Typically, the user sets the particle’s starting position above thesurface as x 0= D/2.The model uses an input file that contains data for the forces created by high-velocity gas flow. Themodel can use data in either of the following formats:Two-dimensional: Based on cylindrical symmetry, in this format, the problem is set up to beindependent of the azimuth angle. The two-dimensional data used in this project was created bycomputational fluid dynamics (CFD) software.Three-dimensional: The full three-dimensional case makes no assumption of symmetries. Threedimensionaldata was created with Direct Simulation Monte Carlo (DSMC) software, which usesprobabilistic simulation to solve the Boltzmann equation for fluid flows. Individual molecules aremoved through a simulation of physical space in a realistic manner that is directly coupled to physicaltime such that unsteady flow characteristics can be modeled. Intermolecular collisions and moleculesurfacecollisions are calculated by means of probabilistic, phenomenological models. The DSMCmethod assumes that the molecular movement and collision phases can be decoupled over periodsshorter than the mean collision time. Figures 1 and 2 show simulation model geometry on the lunarsurface with corresponding simulated craters.For a particle of diameter D and mass m,the trajectory from drag can be estimated bya Taylor series expansion about time pointk, resulting in a set of discrete-differenceequations for position and velocity, usingconstant lunar gravity g Land lunar soil particledensity r L. The CFD/DSMC output providesestimates of gas density r(r)and gas velocityu(r). These values are interpolated from theCFD/DSMC grid by the identification ofthe nearest grid neighbors around the kthtrajectory point and the application of anN-dimensional interpolation algorithm. SeeFigure 3.Figure 1. Three-dimensional simulation geometry with equal-size cratersat varying distances from the rocket blast center.The coefficient of drag, C D, is a function ofthe computed Reynolds number, R e. Liftacceleration caused by the vertical gradientof the horizontal component of gas flow isalso computed, with the use of an estimatedcoefficient of lift, C L. Since particle lift anddrag coefficients (especially lift) are unknownat these high Mach and rarefied flow42 Spaceport Structures and Materials
Figure 2. Three-dimensional simulation geometry with varying cratersizes at equal distances from the rocket blast center.Figure 3. Trajectory plots of 90-µm lunar dust particles initialized to varying distancesfrom the rocket blast center.conditions, the simulation results for various particle sizes and trajectory angles are adjusted ad hoc to match Apollovideo photogrammetry.The gas properties, density, velocity vector, and temperature predicted by the CFD/DSMC simulations allow us tocompute the forces on a single particle of regolith. Once these forces are known, the trajectory path and velocity ofthe particle are computed. Note that all calculations of trajectory assume that the duration of particle flight is muchshorter than the change in gas properties. In other words, the particle trajectory calculations take into account thespatial variation of the gas jet, but not the temporal variation. This is a reasonable first-order assumption.Contact: Dr. Philip T. Metzger , NASA-KSC, (321) 867-6052Participating Organization: ASRC Aerospace (Dr. Christopher D. Immer and Dr. John E. Lane)KSC Technology Development and Application 2006-200743
Page 5 and 6: ForewordSuccessful technology devel
Page 7 and 8: ContentsSpaceport Structures and Ma
Page 9 and 10: Contents (continued)Process and Hum
Page 11 and 12: IntroductionJohn F. Kennedy Space C
Page 13 and 14: Constellation SystemsSurfaceSystems
Page 15 and 16: Spaceport Structures and MaterialsK
Page 17 and 18: 20181614∆ E1210Modified Sensor Be
Page 19 and 20: Initial results of the EDEM model o
Page 21 and 22: Contacts: Dr. Carlos I. Calle ,NASA
Page 23 and 24: Close examination of the corrosions
Page 25 and 26: Adhesion at Failure (psi)2500200015
Page 27 and 28: Figure 1. After 500 hours of salt f
Page 29 and 30: Contacts: Dr. Paul E. Hintze , NASA
Page 31 and 32: Figure 2. Repairs to various types
Page 33 and 34: on top of the cuvette contains the
Page 35 and 36: Figure 2. A corrugated NiTi sheet e
Page 37 and 38: The PLTD can be used to (1) calibra
Page 39 and 40: SEM images of neat MWNT fibers: (a)
Page 41 and 42: Contacts: Trent M. Smith
Page 43 and 44: Figure 1. An isometric cutaway view
Page 45 and 46: Figure 2. Quartz sand flowing in th
Page 47 and 48: Figure 2. Top images show how the e
Page 49 and 50: Sand volume fraction contour at t =
Page 51 and 52: Integrated LWRD/RVC engineering bre
Page 53 and 54: Mean relative percentage change in
Page 55: We compared the model’s predictio
Page 59 and 60: Figure 3. Camera calibration model.
Page 61 and 62: The sketch in Figure 2 shows alaunc
Page 63: Figure 2. Signal generator (right)
Page 66 and 67: Hail Size Distribution MappingA 3-D
Page 68 and 69: Launch Pad 39 Hail Monitor Array Sy
Page 70 and 71: Autonomous Flight Safety System - P
Page 72 and 73: The Photogrammetry CubeSpaceport/Ra
Page 74 and 75: Bird Vision SystemThe Bird Vision s
Page 76 and 77: Automating Range Surveillance Throu
Page 78 and 79: Next-Generation Telemetry Workstati
Page 80 and 81: GPS Metric Tracking UnitAs Global P
Page 82 and 83: Space-Based RangeSpace-Based Range
Page 85 and 86: Fluid System TechnologiesKSC Techno
Page 87 and 88: 0.900.850.80Discharge Coefficient,
Page 89 and 90: Composite seals for performance eva
Page 91 and 92: 140000120000100000Signal80000600004
Page 93 and 94: Contacts: Dr. Barry J. Meneghelli ,
Page 95 and 96: 60555045Comparative k-value (mW/m-K
Page 97 and 98: a compatible spacecraft model where
Page 99 and 100: In an ongoing effort for improvemen
Page 101: Low-gravity probe prototype test.th
Page 104 and 105: Countermeasure for Radiation Protec
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Focused Metabolite Profiling for Di
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Process and Human FactorsEngineerin
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DON uses game technology to enable
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Type of mobile crane that impacted
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SALT proof-of-concept communication
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SSLM CAD model.Our design offers th
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Variables that can be integrated by
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Exploration Supply Chain Simulation
Page 124 and 125:
Nanosensors for Evaluating Hazardou
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Sixty-four-Channel Inline Cable Tes
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Wireless Inclinometer Calibration S
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Generating Safety-Critical PLC Code
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Spacecraft Electrostatic Radiation
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Ion Beam Propulsion StudySpacecraft
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RT-MATRIX: Measuring Total Organic
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Appendix AKSC High-Priority Technol
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Risk Assessment ToolMission Data Fe
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Appendix BInnovative Partnership Pr
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system for the Government, using th
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tracking objects after launch, and
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2006-2007 - Kennedy Space Center Technology Transfer Office

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