Abstract. Thermal structure of the atmosphere of Jupiter was measured from 1029 km above to 133 km below the 1-bar level during entry and descent of the Galileo probe. The data confirm the hot exosphere observed by Voyager (---900 K at 1 nanobar). The deep atmosphere, which reached 429 K at 22 bars, was close to dry adiabatic from 6 to 16 bars within an uncertainty ---0.1 K/km. The upper atmosphere was dominated by gravity waves from the tropopause to the exosphere. Shorter waves were fully absorbed below 300 km, while longer wave amplitudes first grew, then were damped at the higher altitudes. A remarkably deep isothermal layer was found in the stratosphere from 90 to 290 km with T ---160 K. Just above the tropopause at 260 mbar, there was a second isothermal region ---25 km deep with T ---112 K. Between 10 and 1000 mbar, the data substantially agree with Voyager radio occultations. The Voyager 1 equatorial occultation was similar in detail to the present sounding through the tropopause region. The Voyager IRIS average thermal structure in the north equatorial belt (NEB) approximates a smoothed fit to the present data between 0.03 and 400 mbar. Differences are partly a result of large differences in vertical resolution but may also reflect differences between a hot spot and the average NEB. At 15 < p < 22 bars, where it was necessary to extrapolate the pressure calibration to sensor temperatures up to 118øC, the data indicate a stable layer in which stability increases with depth. Consistent with the indication of stability, regular fluctuations in probe vertical velocity imply gravity waves in this layer. At p > 4 bars, probe descent velocities derived from the data are consistently unsteady, suggesting the presence of large-scale turbulence or gravity waves. However, there was no evidence of turbulent temperature fluctuations >0.12 K. A conspicuous pause in the rate of decrease of descent velocity between 1.1 and 1.35 bars, where a disturbance was also detected by the two radio Doppler experiments, implies strong vertical flow in the cloud seen by the probe nephelometer. At p < 0.6 bar, measured temperatures were ---3 K warmer than the dry adiabat, possible evidence of radiative warming. This could be associated with a tenuous cloud detected by the probe nephelometer above the 0.51 bar level. For an ammonia cloud to form at this level, the required abundance is ---0.20 x solar. IntroductionThis paper reports principal results of the Galileo probe atmosphere structure experiment. The primary goal of the experiment was to define the thermal structure of Jupiter's atmosphere below the clouds, a region inaccessible to remote sensing, by direct sensing of atmospheric temperature and , 1996]. It was our intent to obtain measurements through and well below the clouds, to improve accuracy and resolution, and so to define the atmospheric stability against overturning, observe thermal effects of clouds, detect and quantify turbulence, and make other dynamical observations.Densities at a few levels in the upper atmosp...

An implicit ablation and thermal response program is presented for simulation of one-dimensional transient thermal energy transport in a multilayer stack of isotropic materials and structure that can ablate from a front surface and decompose in depth. The governing equations and numerical procedures for solution are summarized. Solutions are compared with those of an existing code, CMA, and also with arcjet data. Numerical experiments show that the new code is numerically more stable and solves a much wider range of problems compared with the older code. To demonstrate its capability, applications for thermal analysis and sizing of aeroshell heatshields for planetary missions of Stardust, Mars Microprobe (Deep Space II), Saturn Entry Probe, and Mars 2001, using advanced lightweight ceramic ablators developed at NASA Ames Research Center, are presented and discussed. Nomenclature a = absorption coef cient, m ¡1 B 0 = dimensionless mass blowing rate, P m=½ e u e C M B a = pre-exponential constant in Eq. (8), s ¡1 C H = Stanton number for heat transfer C M = Stanton number for mass transfer c p = speci c heat, J/kg-K E a = activation temperature in Eq. (8), K F = view factor g = outward pyrolysis mass ux, kg/m 2 -s h = enthalpy, J/kg N h = partial heat of charring, de ned in Eq. (6), J/kg I 0 = radiation source function in Eq. (2), W/m 2 -sr i C = radiant intensity in Cx direction, W/m 2 -sr i ¡ = radiant intensity in ¡x direction, W/m 2 -sr K = extinction coef cient, a C ¾ s , m ¡1 k = thermal conductivity, W/m-K P m = mass ux, kg/m 2 -s P = pressure, N/m 2 q C = conductive heat ux, W/m 2 q R = radiative heat ux, W/m 2 R = universal gas constant, J/kmol-K s = surface recession, m P s = surface recession rate, m/s T = temperature, K u = velocity, m/s x = moving coordinate, y ¡ s, m y = stationary coordinate, m Z ¤ = coef cient in Eq. (9), de ned in Ref. 10 ® = surface absorptance 0 = volume fraction of resin " = surface emissivity µ = time, s · = optical thickness · D = optical thickness for path of length Ḑ = blowing reduction parameter ½ = density, kg/m 3 ¾ = Stefan-Boltzmann constant, W/m 2 -K 4 ¾ s = scattering coef cient, m ¡1 ¿ = mass fraction of virgin material, de ned in Eq. (5) 9 = decomposition reaction order in Eq. (8) Subscripts c = char e = boundary-layeredge g = pyrolysis gas i = density component (A, B, and C ) j = surface species v = virgin w = wall

Phenolic Impregnated Carbon Ablator was the heatshield material for the Stardust probe and is also a candidate heatshield material for the Orion Crew Module. As part of the heatshield qualification for Orion, physical and thermal properties were measured for newly manufactured material, included emissivity, heat capacity, thermal conductivity, elemental composition, and thermal decomposition rates. Based on these properties, an ablation and thermal-response model was developed for temperatures up to 3500 K and pressures up to 100 kPa. The model includes orthotropic and pressure-dependent thermal conductivity. In this work, model validation is accomplished by comparison of predictions with data from many arcjet tests conducted over a range of stagnation heat flux and pressure from 107 W/cm2 at 2.3 kPa to 1100 W/cm2 at 84 kPa. Over the entire range of test conditions, model predictions compare well with measured recession, maximum surface temperatures, and indepth temperatures. Nomenclature A, B, C, D = four thermocouple placement options E = fractional error in recession I, II, III = three model geometry options S = centerline recession, mm X, Y = Cartesian coordinates perpendicular to Z, cm Z = Cartesian coordinate parallel to the axis of the geometry, cm

Temperatures in Jupiter's atmosphere derived from Galileo Probe deceleration data increase from 109 kelvin at the 175-millibar level to 900 ± 40 kelvin at 1 nanobar, consistent with Voyager remote sensing data. Wavelike oscillations are present at all levels. Vertical wavelengths are 10 to 25 kilometers in the deep isothermal layer, which extends from 12 to 0.003 millibars. Above the 0.003-millibar level, only 90- to 270- kilometer vertical wavelengths survive, suggesting dissipation of wave energy as the probable source of upper atmosphere heating.

A formulation of finite rate ablation surface boundary conditions, including oxidation, nitridation, and sublimation of carbonaceous material with pyrolysis gas injection, based on surface species mass conservation, has been developed. These surface boundary conditions are discretized and integrated with a Navier-Stokes solver. This numerical procedure can predict aerothermal heating, chemical species concentration, and carbonaceous material ablation rates over the heat-shield surface of reentry space vehicles. Two finite rate gas-surface interaction models, based on the work of Park and of Zhluktov and Abe, are considered. Three test cases are studied. The stream conditions of these test cases are typical for Earth reentry from a planetary mission with both oxygen and nitrogen fully or partially dissociated inside the shock layer. Predictions from both gas-surface interaction models are compared with those obtained by using chemical equilibrium ablation tables. Stagnation point convective heat fluxes predicted by using Park's finite rate model are usually below those obtained from chemical equilibrium tables and Zhluktov and Abe's model. Recession predictions from Zhluktov and Abe's model are usually lower than those obtained from Park's model and from chemical equilibrium tables. The effect of species mass diffusion on the predicted ablation rate is also examined. Nomenclature B= dimensionless mass blowing rate,ṁ/ρ e u e C m C i = mass fraction for species i C m = Stanton number for mass transferm 2 /s D = bifurcation diffusion coefficient, m 2 /s E = total energy per unit volume, J/m 3 F = nonlinear equation, Eq. (24), or P 0 / √ (2πm i kT ) f i = diffusion factor of species i h = Planck's constant, J · s, or enthalpy, J/kg J = mass diffusion flux, kg/m 2 · s K i = equilibrium constant K t = thermal conductivity of translation temperature, W/m · K K v = thermal conductivity of vibration temperature, W/m · K k = Boltzmann constant, J/K k f = forward reaction rate, Eq. (18) k r = backward reaction rate, Eq. (18) M = molecular weight, kg/mole m i = mass of species i, kġ m = mass flux, kg/m 2 · ŝ N i = Eq. (12) p = pressure, N/m 2 p E = saturated vapor pressure, N/m 2 Q T − v = rate of translation and vibration energy exchange, W/m 3 q conv = convective heat flux, W/m 2 q v = heat flux due to species diffusion, W/m 2 R = universal gas constant, J/kmol · K R b = base radius, m R c = corner radius, m R n = nose radius, m r i = reaction rate; Eq. (14) S = recession rate, m/s T = temperature, K t = time, s u = fluid velocity, m/s v s = species diffusion velocity, m/s v w = mass injection velocity, m/s w = species source term in Eq. (1), kg/m 3 · s x = Cartesian coordinate system, m Z i = bifurcation diffusion quantity of species i; Eq. (4) α = surface absorptance β = efficiency of gas-surface interaction ε = surface emissivity ε i = factor in ith heterogeneous reaction η = general body-fitted coordinate system normal to surface, m i = surface coverage concentration of species i 0 = free surface concentration λ = blowi...