Post-Flight Analysis of the Stardust Sample Return Capsule Earth Entry

Kontinos, Dean; Stackpoole, Mairead

doi:10.2514/6.2008-1197

Cited by 30 publications

(14 citation statements)

References 10 publications

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“…Note that there is significant uncertainty in the modeling parameters required to treat this mechanism. Also, post flight analyses of the Stardust heat shield recession 70 and observed radiation 71 data do not indicate the presence of excessive radiation that may be attributed to spalled particle emission. The same is true for the present analysis of the Apollo 4 flight data presented in Section VI, where good agreement with the flight data is found without accounting for spalled particle emission.…”

Section: Radiation Modeling Of Air With Ablation Productsmentioning

confidence: 99%

Influence of Ablation on Radiative Heating for Earth Entry

Johnston

Gnoffo

Sutton

2009

Journal of Spacecraft and Rockets

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Using the coupled ablation and radiation capability recently included in the LAURA flowfield solver, this paper investigates the influence of ablation on the shock-layer radiative heating for Earth entry. The extension of the HARA radiation model, which provides the radiation predictions in LAURA, to treat a gas consisting of the elements C, H, O, and N is discussed. It is shown that the absorption coefficient of air is increased with the introduction of the C and H elements. A simplified shock layer model is studied to show the impact of temperature, as well as the abundance of C and H, on the net absorption or emission from an ablation contaminated boundary layer. It is found that the ablation species reduce the radiative flux in the vacuum ultraviolet, through increased absorption, for all temperatures. However, in the infrared region of the spectrum, the ablation species increase the radiative flux, through strong emission, for temperatures above 3,000 K. Thus, depending on the temperature and abundance of ablation species, the contaminated boundary layer may either provide a net increase or decrease in the radiative flux reaching the wall. To assess the validity of the coupled ablation and radiation LAURA analysis, a previously analyzed Mars-return case (15.24 km/s), which contains significant ablation and radiation coupling, is studied. Exceptional agreement with previous viscous shock-layer results is obtained. A 40% decrease in the radiative flux is predicted for ablation rates equal to 20% of the free-stream mass flux. The Apollo 4 peak-heating case (10.24 km/s) is also studied. For ablation rates up to 3.4% of the free-stream mass flux, the radiative heating is reduced by up to 19%, while the convective heating is reduced by up to 87%. Good agreement with the Apollo 4 radiometer data is obtained by considering absorption in the radiometer cavity. For both the Mars return and the Apollo 4 cases, coupled radiation alone is found to reduce the radiative heating by 30 -60% and the convective heating by less than 5%. = thickness of the constant-property layers defined in Fig. 3, with i = 1 or 2 (cm) h = absorption coefficient (cm -1 ) = blowing reduction parameter = trasmissivity defined in Eq. (2) Subscripts h = indicates a spectral dependence in terms of eV Superscripts abl = refers to ablation species, meaning species containing any C or H atoms air = refers to air species, meaning species containing no C or H atoms Abbreviations eV = electron volts; the frequency in eV, labeled h , is equal to 1.24x10 -4 / c IR = infrared; refers here to the spectral region below 6 eV NIST = National Institute of Standards and Technology OP = Opacity Project VUV = vacuum ultraviolet; refers to the spectral region above 6 eV

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Section: Radiation Modeling Of Air With Ablation Productsmentioning

confidence: 99%

Influence of Ablation on Radiative Heating for Earth Entry

Johnston

Gnoffo

Sutton

2009

Journal of Spacecraft and Rockets

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“…In contrast, the fastest Apollo capsule, the unmanned Apollo 4, returned with a speed of 11:0 km=s. A comparison of the SRC computational models with the SRC flight-test data revealed that the computational models used to predict such parameters as recession and temperature on the SRC had overpredicted those values, sometimes by more than 50% [4]. The computational models used to generate the predicted data took into account nonequilibrium flow conditions, but assumed equilibrium at the surface.…”

mentioning

confidence: 97%

Significance of Nonequilibrium Surface Interactions in Stardust Return Capsule Ablation Modeling

Beerman

Lewis

Starkey

et al. 2009

Journal of Thermophysics and Heat Transfer

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The gas-surface modeling of high-density materials exposed to high-pressure atmospheric reentry conditions was extended to include low-density materials interacting with low-pressure atmospheric conditions. The fully implicit ablation thermal response code and multicomponent ablation thermochemistry program were extended to include nonequilibrium surface conditions for the Stardust return capsule. The Stardust return capsule reentered Earth's atmosphere experiencing low pressure and had a low-density heat shield material. The material response of the Stardust return capsule was previously only modeled with surface equilibrium. Validation against Stardust reentry flight data showed that the equilibrium assumption led to an overprediction of recession and that the inclusion of nonequilibrium reduced the overprediction of this parameter. Incorporating the Park finite rate model nonequilibrium surface conditions led to a reduction in the calculated value of recession at the stagnation point from 1.12 to 0.72 cm in a nominal simulation of the Stardust return capsule. The nonequilibrium recession was closer to the measured recession of 0.65 cm. Incorporating nonequilibrium conditions also decreased the calculated total heat load from 28 to 19 kJ=cm 2 . The improved material response method is applicable to a range of reentries, including future missions such as the Orion crew exploration vehicle. NomenclatureB = preexponential factor, s 1 B 0 = dimensionless mass blowing rate, _ m= e u e C M C H = Stanton number for heat transfer C i = mass fraction for species i C M = Stanton number for mass transfer c p = specific heat, J=kg-K D i = diffusion coefficient for species i, m 2 =s E = activation temperature, K F = view factor H r = recovery enthalpy, J=kg h = enthalpy, J=kg h = partial heat of charring, J=kg k = Boltzmann constant, J=K M = molecular weight, kg=mole m = mass, kg _ m = mass flux, kg=m 2 s p = pressure, N=m 2 q c = conductive heat flux, W=m 2 q rad = radiative heat flux, W=m 2 T = temperature, K u = velocity, m=s v w = mass injection velocity, m=s x = moving coordinate system, y s, m Y = element mass fraction y = stationary coordinate, m = surface absorption = efficiency of gas-surface interaction = volume faction of resin " = surface emissivity = blowing reduction parameter = density, kg=m 3 = Stefan-Boltzmann constant, W=m 2 K 4 = decomposition reaction order Subscripts c = char d = density component e = boundary-layer edge g = pyrolysis gas i = surface species k = element or gaseous base species s = surface v = original w = wall

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“…Sumio KATO 1) , Keiichi OKUYAMA 2) , Kenta GIBO 1) , Takuma MIYAGI 1) , Toshiyuki SUZUKI 3) , Kazuhisa FUJITA 3) , Takeharu SAKAI 4) , Seiji NISHIO 5) and Akihiro WATANABE 1)…”

Section: Thermal Response Simulation Of Ultra Light Weight Phenolic Cunclassified

“…On the other hand, the use of a low density ablator gives a weight reduction of the heat shield system, and the lightweight ablator with the density values of about 300kg/m 3 has been developed 4) and used for the heat protection of the Stardust Capsule 5) . Recently, a lightweight ablator named LATS (Lightweight ablator series for Transfer Vehicle) has been developed 6) , the density of which is lower by about one-fifth of the carbon phenolic ablators in the past space mission mentioned above.…”

Section: Introductionmentioning

confidence: 99%

Thermal Response Simulation of Ultra Light Weight Phenolic Carbon Ablator by the Use of the Ablation Analysis Code

Kato

Okuyama

Gibo

et al. 2012

AEROSPACE TECHNOLOGY JAPAN

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A space vehicle which undergoes the atmospheric re-entry or a planetary entry needs the heat shield system to protect inner equipments against severe aerodynamic heating environments. Charring ablator is usually used for the heat shield system. In order to design the heat shield system, it is necessary to predict the thermal behavior under aerodynamic heating by ablation analysis. A computer code for charring ablation and thermal response analysis is newly developed for simulation of one-dimensional transient thermal behavior of charring ablation materials. The mathematical model for the charring ablation including basic equation and computational method of ablation analysis is briefly described. A new ultra light weight phenolic carbon ablator called LATS (Lightweight Ablator series for Transfer vehicle) was recently developed. Arc-heated tests of the LATS ablator were carried out and measured results of the temperature response and surface mass loss are compared with the simulation results of the ablation analysis program. The agreement between the results of simulation and measurement is found to be good. It is also found that the mathematical model used in the ablation code can be applied to the ablation analysis of the low density LATS ablator.

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Post-Flight Analysis of the Stardust Sample Return Capsule Earth Entry

Cited by 30 publications

References 10 publications

Influence of Ablation on Radiative Heating for Earth Entry

Influence of Ablation on Radiative Heating for Earth Entry

Significance of Nonequilibrium Surface Interactions in Stardust Return Capsule Ablation Modeling

Thermal Response Simulation of Ultra Light Weight Phenolic Carbon Ablator by the Use of the Ablation Analysis Code

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