Aerothermal heating predictions for Mars Microprobe

Mitcheltree, Robert A.; DiFulvio, Michael; Horvath, Thomas J.; Braun, Robert D.

doi:10.2514/6.1998-170

Cited by 12 publications

(5 citation statements)

References 8 publications

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“…19). This is particularly true for the small Microprobe capsules since heating rates will be quite high and the rarefied effects will persist to peak heating-rate conditions.…”

Section: Included Inmentioning

confidence: 93%

DSMC simulations of blunt body flows for Mars entries - Mars Pathfinder and Mars Microprobe capsules

Moss

Wilmoth

Price

1997

32nd Thermophysics Conference

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ABSflRACTThe hypersonic transitional flow aerodynamics of the Mars Pathfinder and Mars Microprobe capsules are simulated with the direct simulation Monte Carlo method. Calculations of axial, normal, and static pitching coefficients were obtained over an angle of attack range comparable to actual flight requirements.Comparisons are made with modified Newtonian and free-molecular-flow calculations. Aerothermal results were also obtained for zero incidence entry conditions. NOMENCLATURE acceleration axial force coefficient drag coefficient heat transfer coefficient mass fraction of species i normal force coefficient pitching moment coefficient about center of gravity pitching moment coefficient about nose maximum probe diameter Knudsen number pressure heat transfer rate afterbody radius maximum probe radial dimension comer radius *Aerospace Engineer, Aerothermodynamics Branch, Aero-and Gas-Dynamics Division, Fellow AIAA. +Aerospace Engineer, Aerothermodynamics Branch, Aero-and Gas Dynamics Division, Senior Member AIAA *Aerospace Engineer, Aerothermodynamics Branch, Aero-and Gas Dynamics Division. INTRODUCTIONDuring the next decade, mapping and inspection missions to Mars will occur with considerable frequency utilizing orbiters, landers and penemtors. The NASA Planetary Exploration Program plans for a pair of spacecraft to be sent to Mars every twentysix months for the next five years. This activity was initiated in late 1996 with two successful launches: first, the Mars Global Surveyor spacecraft which will provide an orbiting platform and, second, the Mars Pathfinder scheduled for a Mars landing July 4, 1997.The Mars Pathfinder mission will demonstrate a low-cost delivery system** to the surface of Mars while providing unique opportunities for scientific exploration. The entry vehicle contains a scientific instrument platform and a small rover that will be placed on the surface of Mars. Pathfinder is viewed as is statically unstable for the k molecular and much of the transitional flow regime, that is, the flow regime bounded by fke molecular and continuum flow. However, as shown from trajectory calculations, the gyroscopic effect of the vehicle spin is adequate for preventing unacceptable increases in vehicle attitude during the transitional portion of entry. A second requirement for Pathfinder rarefied aerodynamics is to support the atmospheric structure experiment where data obtained from accelerometer measurements will allow the extraction of atmospheric density as well as pressure and temperature. Accuracy of the atmospheric structure experiment depends directly on the accuracy of the probe axial force coefficients.Upon arrival at Mars, the Microprobes will be released from the Surveyor spacecraft and begin a k fall to the surface. The capsule forebody is a spherically blunted 45" half angle cone followed by a hemispherical backshield with a maximum body diameter of 0.35 m. A unique aspect of the Microprobes' entries is that the vehicles will encounter Mars' outer atmosphere in a random state, potentially t...

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“…19). This is particularly true for the small Microprobe capsules since heating rates will be quite high and the rarefied effects will persist to peak heating-rate conditions.…”

Section: Included Inmentioning

confidence: 93%

DSMC simulations of blunt body flows for Mars entries - Mars Pathfinder and Mars Microprobe capsules

Moss

Wilmoth

Price

1997

32nd Thermophysics Conference

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“…A simple but quiet accurate equation for estimating heating flux in designing entry probe is (Mitcheltree et al, 1998):…”

Section: Robust Design Of Mars Entry Micro-probementioning

confidence: 99%

Robust design of Mars entry micro-probe with evidence theory and multi-fidelity strategies

Hou

Cai

Zhang

et al. 2014

Engineering Computations

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Purpose -A multi-disciplinary robust design optimization method for micro Mars entry probe (no more than 0.8 m in diameter) is proposed. The purpose of this paper is to design a Mars entry probe, not only the geometric configuration, but the trajectory and thermal protection system (TPS). In the design optimization, the uncertainties of atmospheric and aerodynamic parameters are taken into account. The probability distribution information of the uncertainties are supposed to be unknown in the design. To ensure accuracy levels, time-consuming numerical models are coupled in the optimization. Multi-fidelity approach is designed for model management to balance the computational cost and accuracy. Design/methodology/approach -Uncertainties which cannot defined by usual Gaussian probability distribution are modeled with degree of belief, and optimized through with multiple-objective optimization method. The optimization objectives are set to be the thermal performance of the probe TPS and the corresponding belief values. Robust Pareto front is obtained by an improved multi-objective density estimator algorithm. Multi-fidelity management is performed with an Artificial Neural Network (ANN) surrogate model. Analytical model is used first, and then with the improvement of accuracy, rather complex numerical models are activated. ANN updates the database during the optimization, and makes the solutions finally converge to a high-level accuracy. Findings -The optimization method provides a way for conducting complex design optimization involving multi-discipline and multi-fidelity models. Uncertainty effects are analyzed and optimized through multi-disciplinary robust design. Because of the micro size, and uncertain impacts of aerodynamic and atmospheric parameters, simulation results show the performance trade-off by the uncertainties. Therefore an effective robust design is necessary for micro entry probe, particularly when details of model parameter are not available.The current issue and full text archive of this journal is available at Originality/value -The optimization is performed through a new developed multi-objective density estimator algorithm. Affinity propagation algorithm partitions adaptively the samples by passing and analyzing messages between data points. Local principle component techniques are employed to resample and reproduce new individuals in each cluster. A strategy similar to NSGA-II selects data with better performance, and converges to the Pareto front. Models with different fidelity levels are incorporated in the multi-disciplinary design via ANN surrogate model. Database of aerodynamic coefficients is updated in an online manner. The computational time is greatly reduced while keeping nearly the same accuracy level of high fidelity model.

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“…After numerical integration, the C D A and C L A are obtained for the aeroshell and L/D is computed using Eq. (2). Similarly, C M Al is obtained directly through numerical integration over the aeroshell surface mesh, referenced to the centroid of the aeroshell.…”

Section: Aerodynamic Objectives and Constraintsmentioning

confidence: 99%

“…Various aeroshell shapes. [1][2][3][4] landed payload masses. As mentioned previously, minimizing β will reduce heating; however, this is a trajectory effect and the local aerothermodynamic environment will be defined at every point on the surface by the aeroshell geometry (e.g., local curvature).…”

Section: Introductionmentioning

confidence: 99%