Galileo Probe Heat Shield Ablation Experiment

Milos, Frank S.

doi:10.2514/2.3293

Cited by 113 publications

(28 citation statements)

References 11 publications

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“…Measurements of a test vehicle with a low-drag (␦ ϭ 0.06) carbon nosecone entering the Earth's atmosphere at 6 km͞sec showed an ablative loss of Ϸ0.1 kg, for a mass-loss to energy-loss ratio of 0.14 kg͞GJ (10). A similar ratio of 0.25 kg͞GJ was measured for the Galileo probe, which entered Jupiter's atmosphere at 47 km͞sec and was brought to rest by a carbon ablation shield designed for high drag (11). In our case, a 4 ton͞m 2 vehicle losing 77 GJ͞m 2 would suffer an ablation loss of 20 kg͞m 2 , if the loss rate were 0.25 kg͞GJ.…”

Section: From the Earth To L1mentioning

confidence: 65%

Feasibility of cooling the Earth with a cloud of small spacecraft near the inner Lagrange point (L1)

Angel

2006

Proc. Natl. Acad. Sci. U.S.A.

215

171

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If it were to become apparent that dangerous changes in global climate were inevitable, despite greenhouse gas controls, active methods to cool the Earth on an emergency basis might be desirable. The concept considered here is to block 1.8% of the solar flux with a space sunshade orbited near the inner Lagrange point (L1), in-line between the Earth and sun. Following the work of J. Early [Early, JT (1989) J Br Interplanet Soc 42:567-569], transparent material would be used to deflect the sunlight, rather than to absorb it, to minimize the shift in balance out from L1 caused by radiation pressure. Three advances aimed at practical implementation are presented. First is an optical design for a very thin refractive screen with low reflectivity, leading to a total sunshade mass of Ϸ20 million tons. Second is a concept aimed at reducing transportation cost to $50͞kg by using electromagnetic acceleration to escape Earth's gravity, followed by ion propulsion. Third is an implementation of the sunshade as a cloud of many spacecraft, autonomously stabilized by modulating solar radiation pressure. These meter-sized ''flyers'' would be assembled completely before launch, avoiding any need for construction or unfolding in space. They would weigh a gram each, be launched in stacks of 800,000, and remain for a projected lifetime of 50 years within a 100,000-km-long cloud. The concept builds on existing technologies. It seems feasible that it could be developed and deployed in Ϸ25 years at a cost of a few trillion dollars, <0.5% of world gross domestic product (GDP) over that time.geoengineering ͉ global warming ͉ space sunshade P rojections by the Intergovernmental Panel on Climate Change are for global temperature to rise between 1.5 and 4.5°C by 2100 (1), but recent studies suggest a larger range of uncertainty. Increases as high as 11°C might be possible given CO 2 stabilizing at twice preindustrial content (2). Holding to even this level of CO 2 will require major use of alternative energy sources and improvements in efficiency (3). Unfortunately, global warming reasonably could be expected to take the form of abrupt and unpredictable changes, rather than a gradual increase (4). If it were to become apparent over the next decade or two that disastrous climate change driven by warming was in fact likely or even in progress, then a method to reduce the sun's heat input would become an emergency priority. A 1.8% reduction is projected to fully reverse the warming effect of a doubling of CO 2 (5), although not the chemical effects.One way known to reduce heat input, observed after volcanic eruptions, is to increase aerosol scattering in the stratosphere (6). Deployment of 3 to 5 million tons͞year of sulfur would be needed to mitigate a doubling of CO 2 . This amount is not incompatible with a major reduction in the current atmospheric sulfur pollution of 55 million tons͞year that goes mostly into the troposphere. The approach we examine here to reduce solar warming is to scatter away sunlight in space before it enters the Ear...

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Section: From the Earth To L1mentioning

confidence: 65%

Feasibility of cooling the Earth with a cloud of small spacecraft near the inner Lagrange point (L1)

Angel

2006

Proc. Natl. Acad. Sci. U.S.A.

215

171

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“…1,2 As a result, massive ablation occurred that resulted in a substantial reduction of the heat shield mass. 1 The flight data revealed that there was a significant discrepancy of the final recession profile from that given by the preflight prediction. Indeed, the amount of recession occurred at the stagnation region deduced from the flight data was almost three-fourths and that at the frustum region was almost double when compared with those given by the preflight prediction.…”

Section: Introductionmentioning

confidence: 82%

Multiband Radiation Model for Simulation of Galileo Probe Entry Flowfield

Matsuyama

Shimogonya²,

Ohnishi

et al. 2006

Journal of Thermophysics and Heat Transfer

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Nomenclature A 1 -A 5 = fitting parameters in Eq. (2) c 1 -c 4 = coefficients in Eq. (3) n = molar concentration, mol/m 3 T = temperature, K κ λ = absorption coefficient at given wavelength, m −1 λ = wavelength,Å σ λ = absorption cross section at given wavelength, m 2 /mol Subscripts e = electron i = species i itb = index of table data point for temperature jtb = index of table data point for electron number density Superscripts i = species i

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“…Forebody distributions of radiative heating at different trajectory locations [58]. The flight data have been analysed [70,71] and the entry trajectory, as well as the atmospheric properties have been determined. They are all reported in Table 6.…”

Section: Survey and Computational Matrixmentioning

confidence: 99%

“…Galileo probe was equipped with ablation detector sensors (ARAD) for collecting flight data during entry. The in-flight experiments have been well detailed by Milos [70]. Ten ablation sensors were included in the TPS, at 6 different locations, as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

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Radiative Aerothermodynamics of Entering Space Vehicles: Toward the Use of State-to-State Approach

Суржиков¹,

Reynier²,

Seller³

et al. 2014

TOPPJ

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Modern problems of radiative aerothermodynamics of entering space vehicles are demonstrated and analyzed in the paper. New radiative gas dynamic problems concerned to coupling processes of non-equilibrium dissociation with radiation heat transfer in shock layers generated above large scale re-entry space vehicles returning from orbital and super orbital space mission are considered in the first part.Three-dimensional numerical simulation data on radiative aerothermodynamics of Martian entry probes Pathfinder, Exomars and Mars Science Laboratory (MSL) are presented and analyzed in the second part. It is shown that integral radiative heating of leeward surface of the entry probes exceeds corresponding convective heating.The third part is dedicated to consideration preliminary numerical simulation results on radiative gas dynamics of Galileo probes. At first, a review of the available results obtained during the mission preparation and post-flight analyses has been undertaken to select a computational matrix. This matrix has been selected by accounting for previous numerical efforts from the literature to crosscheck the results. Then, a model based on previous efforts has been set up for computing the flow-field around the probe at high altitude. Finally the test case matrix has been computed and crosschecked with existing numerical predictions performed.Some possibilities of innovative magneto-hydrodynamic (MHD) technologies being applied to solve problems of re-entry vehicles heat protection are discussed in the fourth part.All presented data demonstrate necessity of further development of the radiative aerothermodynamics based on state-tostate approaches.

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Galileo Probe Heat Shield Ablation Experiment

Cited by 113 publications

References 11 publications

Feasibility of cooling the Earth with a cloud of small spacecraft near the inner Lagrange point (L1)

Feasibility of cooling the Earth with a cloud of small spacecraft near the inner Lagrange point (L1)

Multiband Radiation Model for Simulation of Galileo Probe Entry Flowfield

Radiative Aerothermodynamics of Entering Space Vehicles: Toward the Use of State-to-State Approach

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