Mars Pathfinder Entry, Descent, and Landing Reconstruction

Spencer, David A.; Blanchard, Robert C.; Braun, Robert D.; Kallemeyn, P. H.; Thurman, S. W.

doi:10.2514/2.3478

Cited by 143 publications

(62 citation statements)

References 11 publications

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“…8 have demonstrated that sonic line motion between the shoulder and sphere-cone junction due to real gas effects results in a hypersonic aerodynamic instability and corresponding aerothermal effects on the 70-deg sphere-cone Pathfinder geometry; a prediction later confirmed by entry data. 9 The design of a low mass and reliable (low risk) TPS system for Martian atmospheric entry requires an accurate prediction of the aerothermal environment encountered by the spacecraft during entry. The peak heat flux (along with surface pressure and shear stress) will drive the selection of the thermal protection material for the heatshield, while the total integrated heat load determines the required thickness of TPS material.…”

Section: Introductionmentioning

confidence: 99%

A Review of Aerothermal Modeling for Mars Entry Missions

Wright

Tang

Edquist

et al. 2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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The current status of aerothermal analysis for Mars entry missions is reviewed. The aeroheating environment of all Mars missions to date has been dominated by convective heating. Two primary uncertainties in our ability to predict forebody convective heating are turbulence on a blunt lifting cone and surface catalysis in a predominantly CO2 environment. Future missions, particularly crewed vehicles, will encounter additional heating from shock-layer radiation due to a combination of larger size and faster entry velocity. Localized heating due to penetrations or other singularities on the aeroshell must also be taken into account. The physical models employed to predict these phenomena are reviewed, and key uncertainties or deficiencies inherent in these models are explored.

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Section: Introductionmentioning

confidence: 99%

A Review of Aerothermal Modeling for Mars Entry Missions

Wright

Tang

Edquist

et al. 2010

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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“…Fig. 8(b) compares altitude vs. velocity for all the trajectory codes in comparison against the actual pathfinder flight data which is based on the on-board accelerometer measurements (Spencer et al, 1999). The trajectory tools seem to agree with the reconstructed flight data and with the trajectory data generated by Sparta on a machine to machine specific architecture code comparison.…”

Section: Sparta Against Post and Trajoptmentioning

confidence: 81%

Development of an Interactive Hypersonic Flow Solver Framework for Aerothermodynamic Analysis

Subrahmanyam

2008

Engineering Applications of Computational Fluid Mechanics

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Sparta is a three-dimensional finite volume compressible Java based flow solver on multiple block structured grids. The flow solver is graphical user interface driven and platform independent as well. Finite-rate reaction kinetics, thermal and chemical non-equilibrium and high temperature transport coefficients are all developed and incorporated into the solver. Zero, one and two equation turbulence models have been implemented in the solver for turbulence modeling. The flow domain is discretized by a structured grid and a finite-volume approach is used to discretize the conservation equations. One of several schemes can be chosen from the user interface to calculate inviscid fluxes across cell faces while central differences schemes are used to calculate the viscous fluxes. The CFD solver includes a geometry engine to generate surface and volume grids, a trajectory engine to generate trajectory data given the appropriate atmospheric models, an aerodynamic flow solver to calculate the aerodynamic forces and moments and finally hooked to the Navier-Stokes engine. Probe models can also be selected automatically from the graphical user interface and the database. The database comprises vehicle dimensions, trajectory data, and aero-thermal, Thermal Protection Systems data for many different ballistic entry vehicles. Material properties for carbon and silicon based ablators have been obtained and can be accessed from the database. Comparative data analysis capability is achieved through a Relational Database Management System. Atmospheric models can be selected from the graphical user interface so that the multi-species to be solved are automatically populated before the solver is invoked. Sparta has been integrated to a planetary probe database and a trajectory code to study trajectory analysis, aerodynamic heating and flow-field analysis. The purpose of this research is twofold: to investigate a pure Java based multi-threaded CFD solver and to implement a semi-automatic and interactive solver for aerothermodynamics such that grids can be generated automatically given the geometry of the vehicles, trajectory data can be generated given the atmospheric model and TPS material from the graphical interface for the generation of flow field information for atmospheric entry vehicles. Sparta accepts hooks from the trajectory so that inputs for the flow solver can come from the trajectory output making the solver trajectory driven. This paper addresses the CFD development, implementation and capabilities of a hypersonic flow solver Sparta.

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“…The validity of the present approach has been demonstrated recently through comparisons between the Mars Pathfinder pre-flight predictions of the flight dynamics and the actual flight data. 12 During the entry, off-nominal conditions may arise which affect the descent profile. These off-nominal conditions can originate from numerous sources: 1) capsule mass property measurement uncertainties, 2) separation attitude and attitude rate uncertainties, 3) limited knowledge of the flight-day atmospheric properties (density, pressure, and winds), 4) computational uncertainty with the aerodynamic analysis, and 5) uncertainties with para-chute deployment.…”

Section: Trajectory Simulationmentioning

confidence: 99%

Entry Dispersion Analysis for the Genesis Sample Return Capsule

Desai

Cheatwood

2001

Journal of Spacecraft and Rockets

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p.n.desai@larc.nasa.gov, f.m.cheatwood@larc.nasa.gov Genesis will be the first mission to return samples from beyond the Earth-Moon system. The spacecraft will be inserted into a halo orbit about the L1 (SunEarth) libration point where it will remain for two years collecting solar wind particles. Upon Earth return, the sample return capsule, which is passively controlled, will descend under parachute to Utah. The present study describes the analysis of the entry, descent, and landing scenario of the returning sample capsule. The robustness of the entry sequence is assessed through a Monte Carlo dispersion analysis where the impact of off-nominal conditions is ascertained. The dispersion results indicate that the capsule attitude excursions near peak heating and drogue chute deployment are within Genesis mission limits. Additionally, the size of the resulting 3-σ landing ellipse is 47.8 km in downrange by 15.2 km in crossrange, which is within the Utah Test and Training Range boundaries.

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Mars Pathfinder Entry, Descent, and Landing Reconstruction

Cited by 143 publications

References 11 publications

A Review of Aerothermal Modeling for Mars Entry Missions

A Review of Aerothermal Modeling for Mars Entry Missions

Development of an Interactive Hypersonic Flow Solver Framework for Aerothermodynamic Analysis

Entry Dispersion Analysis for the Genesis Sample Return Capsule

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