Reentry Research Articles

Investigation of shock/shock interferences on the aerodynamics of a fragment in the wake of debris in a rarefied regime/at high altitude

This work presents an experimental investigation focused on the analysis of aerodynamic properties between two interacting spheres in a supersonic rarefied flow. Atmospheric re-entries of space debris, whether natural or man-made, begin at altitude 120 km, and observations of historical re-entries have shown that fragmentation occurs between 90 and 50 km. The resulting fragments interact with each other, altering their own trajectories while traversing the different flow regimes between the free molecular and continuum regimes. This study focuses on the intermediate slip regime, where viscous effects of varying magnitude can influence the nature of the interactions of the shocks and modify them from the already known behaviour in the continuum regime. Specifically, this study examines how two spheres interact with each other upon re-entry into the atmosphere, focusing particularly on the six types of shock/shock interactions identified by Edney. The experiments were performed in the MARHy wind tunnel, in a steady Mach 4 laminar flow with static pressure 2.67 Pa. To highlight the differences between the six types of interferences, a variety of set-ups and devices were used: flow-field visualization, aerodynamic forces (through two diagnoses, aerodynamic balance and the swinging sphere technique) and wall pressure measurements. Results demonstrate the identification of differences according to the type of interference observed, showing in particular the viscous effect of rarefied flows by making a comparison with the continuum regime.

Study on the Variation of Gas Radiation Characteristics of Hypersonic Reentry Vehicles

For the nonequilibrium flowfield and high-temperature gas radiation spectral characteristics of the hypersonic reentry capsule, a spectral prediction method based on quasi-steady-state assumption and line-by-line method is introduced. Meanwhile, the characteristics of the spectrum are studied to investigate the influence of viewing angles and trajectory points during reentry based on this method. We use Fire II flight test data to verify the accuracy of the gas radiation model and update the prediction values of the cumulative radiation intensity in the wavelength range of 2.2–4.1 eV by previous methods. The results show that the radiation signal is most significant at the stagnation line and gradually decreases with the deviation of the line of sight from the stagnation line. The cumulative radiation intensity of the various trajectory points exhibits a profile that increases and then decreases during reentry; it rises to its peak at 50 km. The emission spectrum of gas radiation is mainly distributed in the ultraviolet and near-infrared bands. The transition processes of atoms N and O contribute more than 90% of the total radiation intensity, and the contribution of the first negative series in the molecular spectrum is relatively considerable compared to other molecular components.

Metals from spacecraft reentry in stratospheric aerosol particles

Large increases in the number of low earth orbit satellites are projected in the coming decades [L. Schulz, K.-H. Glassmeier, Adv. Space Res. 67, 1002-1025 (2021)] with perhaps 50,000 additional satellites in orbit by 2030 [GAO, Large constellations of satellites: Mitigating environmental and other effects (2022)]. When spent rocket bodies and defunct satellites reenter the atmosphere, they produce metal vapors that condense into aerosol particles that descend into the stratosphere. So far, models of spacecraft reentry have focused on understanding the hazard presented by objects that survive to the surface rather than on the fate of the metals that vaporize. Here, we show that metals that vaporized during spacecraft reentries can be clearly measured in stratospheric sulfuric acid particles. Over 20 elements from reentry were detected and were present in ratios consistent with alloys used in spacecraft. The mass of lithium, aluminum, copper, and lead from the reentry of spacecraft was found to exceed the cosmic dust influx of those metals. About 10% of stratospheric sulfuric acid particles larger than 120 nm in diameter contain aluminum and other elements from spacecraft reentry. Planned increases in the number of low earth orbit satellites within the next few decades could cause up to half of stratospheric sulfuric acid particles to contain metals from reentry. The influence of this level of metallic content on the properties of stratospheric aerosol is unknown.

Comparative analysis of combustion stability and flow performance in micro combustor based on the synergistic action of slotted blunt body and front-baffle

Flame instability is a key problem that needs to be solved, and the existing improvement methods are still insufficient. Different from the traditional single structure improvement, a novel synergistic combustion stabilization method is proposed. In this paper, the conventional blunt body is slotted to achieve “graded combustion”, and the front baffle is embedded on the slotted blunt body to guide fuel flow, thus strengthening the combustion and improving the flame stability. With the help of simulation software Fluent, the combustion characteristics of conventional blunt body micro combustor (CMC), conventional slotted blunt body micro combustor (MCESB) and front-baffle slotted blunt body micro combustor (MCESB-FA) are compared, and further researched the flow characteristics and inlet velocity. According to the findings, the synergistic action of slotted blunt body and baffle is beneficial to improve combustion performance and flame stability, MCESB-FA demonstrates the highest combustion efficiency, the flame breaking limits of the MCESB-FA up to 80 m/s. Besides, the turbulent kinetic energy behind the blunt body is significantly increased, which is conducive to the heat transfer for the central combustion zone and the cold fuel on both sides, so as to achieve strengthening combustion. Interestingly, the backflow area disappears due to the slotting, but the front-baffle embedding breaks the original fuel flow balance and re-forms the backflow area to achieve steady combustion. Finally, as inlet velocity increase, the MCESB-FA and MCESB have better combustion performance and flow distribution, especially under the combination of slotted blunt body and front-baffle.

Control of Base Pressure at Supersonic Mach Number in a Suddenly Expanded Flow

In improving the efficiency of applications for flow over a blunt body like missiles and rockets, passive and active control is used to increase the base pressure, hence reducing the base drag. It must be mentioned that this paper covers mainly a variety of passive control methods in the form of the cavity, rib, splitter plate, spike, and some others to regulate the base pressure and drag force. Later, this paper focuses on the control of base pressure in the form of the cavity at a Mach number of 2.2 and an area ratio of 4.84. In this experiment, Computational Fluid Dynamics (CFD) is used to model a convergent-divergent nozzle and a duct. The cavity’s dimensions and locations are studied to get the optimum cavity’s control of base pressure. Two sizes of the cavity are considered which are 3:3 and 6:3. The L/D is varied from 1, 2, 4, and 6 while the Nozzle Pressure Ratio (NPR) ranges from 3 to 16. The 2-D design of a convergent-divergent axisymmetric nozzle suddenly expanded into a duct with a diameter of 22 mm with and without annular rectangular cavities is sketched using ANSYS. The results show that the base pressure is greatly influenced by the cavity’s dimension and location as well as the NPR.

Advancing high-speed flow simulations: SAUSM – an innovative hybrid numerical scheme for shock stability and accuracy

This paper introduces a novel hybrid numerical method, SAUSM, designed for accurate and robust simulation of compressible flows governed by the Euler equations. While the AUSM[Formula: see text] scheme provides proper resolution of smooth flow features, it is susceptible to anomalies, particularly the carbuncle phenomenon near strong shock discontinuities. Conversely, the AUFS scheme offers inherent stability in capturing shocks; however, it lacks the accuracy of AUSM[Formula: see text] in smooth regions. The proposed SAUSM method combines AUSM[Formula: see text] and AUFS through an adaptive weighting function, facilitating a seamless transition between the schemes. This approach preserves the accuracy of AUSM[Formula: see text] in smooth regions while ensuring robust shock-capturing capabilities near discontinuities. The effectiveness of the SAUSM method is rigorously demonstrated through a comprehensive suite of progressively complex test cases. Numerical experiments demonstrate SAUSM’s proficiency in resolving intense shock patterns and discontinuities without introducing anomalies. In the selected test cases, SAUSM agrees with reference solutions and effectively mitigates anomalies observed in AUSM[Formula: see text], including kinked Mach stems. In the challenging test case involving hypersonic blunt body flow over a cylinder, SAUSM adapts dissipation effectively by utilizing its adaptive weighting function to generate smooth pressure distributions, thereby eliminating the carbuncle instability linked to AUSM[Formula: see text] when applied to a high aspect ratio grid. The consistent formulation of flux splitting and the adaptive weighting in SAUSM prevent excessive dissipation away from discontinuities, thus preserving accuracy comparable to that of exact Riemann solvers. Consequently, SAUSM emerges as a promising and innovative approach to accurately and robustly simulate a wide range of compressible Euler flows. The comprehensive results obtained from the validation tests firmly establish SAUSM as a highly effective general-purpose technique for computational fluid dynamics in academic research.

Finite-rate and equilibrium study of graphite ablation under arc-jet conditions

Arc-jet facilities play a primary role in recreating aerothermal conditions experienced by atmospheric entry vehicles and are widely used to test the performance of thermal protection materials. In this work, we utilize a developed coupled framework between an overset flow solver CHAMPS NBS-Cart, and a material solver KATS-MR to study the ablation of graphite under arc-jet conditions. We implement a 12-species gas phase model to accurately represent the air-carbon mixture, including argon species present in the flow. The gas phase is modeled with a two-temperature thermo-chemical non-equilibrium model without considering electronic and ionization effects. The gas-surface interactions are modeled with a newly developed air-carbon ablation model accounting for oxidation, nitridation, and recombination reactions. In addition, the model is augmented with carbon sublimation reactions experienced at high heating conditions. The chemical state at the surface is tightly coupled with the flow solver, resulting in the improved accuracy and effectiveness of the simulation. The coupled approach is applied to study two experimental test cases conducted at the IHF arc-jet facility at NASA Ames. The predicted results are validated against measured recession, surface, and in-depth temperatures and compared to the prediction of the uncoupled, equilibrium-based approach. Finally, the accuracy of the prediction is explored with respect to the environmental properties, such as the diffusion coefficient, and material thermal conductivity.

Nitrogen thermometry in an inductively coupled plasma torch using broadband nanosecond coherent anti-Stokes Raman scattering.

The development of atmospheric hypersonic flight and re-entry capabilities requires the characterization of the thermo-chemical state of representative test environments. This study demonstrates the usage of multiplex nanosecond N 2 coherent anti-Stokes Raman scattering (CARS) to measure temperatures in an atmospheric, high-temperature (>6000K), air plasma plume, generated by an inductively coupled plasma torch. These are some of the highest temperatures ever accessed via gas-phase CARS, to our knowledge. Temperatures of N 2 in the equilibrium plasma plume are determined via theoretical fits to measured CARS spectra. We discuss the practical implementation of CARS at very high temperatures, including the scaling of the N 2 CARS signal strength from 300 to 6700K, where the expected peak signal from the high-temperature plasma torch gases is two orders of magnitude less than commonly encountered in combustion environments. An intensified CCD camera enables single-laser-shot detection at temperatures as high as 6200K, by increasing sensitivity and providing a time gate against intense background luminosity. We also discuss the impacts of unwanted two-beam CARS contributions from outside the nominal three-beam measurement volume. We present mean axial and radial temperature profiles, as well as time-series data derived from both single-laser-shot and accumulated CARS spectra. The single-laser-shot precision is 1.7%-2.6% at temperatures of 3500 to 6200K. The presented results pave the way for the use of CARS at very high temperatures and the measurement of spatially resolved interface processes in high-enthalpy flows.

Simulation for the Effects of Aerodynamic Actuation on the Reentry Vehicle Plasma Sheath

Simulation for the Effects of Aerodynamic Actuation on the Reentry Vehicle Plasma Sheath

Meteorite material luminous efficiencies from ground testing of meteoroid entry

The paper reports the determination of luminous efficiency values from ground testing of a comprehensive set of meteorite samples. The ground testing data is translated with commonly used ground to flight extrapolation analogies from atmospheric entry maneuver’s engineering into values of a night observation. This results in a meteor at an altitude of 80km with a flight speed of 11.7km/s of a 34.8 mm diameter spherical meteoroid. A method is developed to determine the total luminous efficiency τ in the bands U, B, V, R, and I from the radiance data and the measured mass loss. For the first time, a measurement of luminous efficiency became possible for known materials. The values itself are in the range of 0.01% to ∼ 1%, which is in the range of previous studies from meteor measurements.

Efficient Method for Heat Flux Calculations within Multidisciplinary Analyses of Hypersonic Vehicles

A large amount of heat flux from aerodynamic heating acts on reusable spacecraft; thus, an accurate heat flux prediction around spacecraft reentry is essential for developing a high-performance reusable spacecraft. Although the approximate convective-heating equations can calculate the heat flux with high efficiency and sufficient fidelity, the heat flux should be evaluated over a thousand times for the entire trajectory in multidisciplinary analyses. For these reasons, it is necessary to develop an efficient method for calculating the heat flux for multidisciplinary analysis. In this paper, an efficient method for heat flux calculation that is adoptable by multidisciplinary analyses for hypersonic vehicles, such as spacecraft, is developed. Approximate convective-heating equations were adopted to relieve the computational cost of estimating the heat flux, and an adaptive time step method for heat flux calculations was developed to reduce the number of heat flux calculations required across the entire flight trajectory. A dynamic factor was introduced that adjusts the time step between each instance of the heat flux calculation. Since the time step using this factor could increase under low heat flux conditions, the number of heat flux calculations decreases by approximately one-tenth with over 90% accuracy. Therefore, the efficiency was improved with high accuracy using the adaptively-determined time step according to this dynamic factor.

Oxidation induced emissivity variations of the Haynes 25 alloy at high temperatures

Haynes 25 alloy is used in the design of propulsion systems for spacecrafts and it can constitute a space debris at the end of life of the mission. All the thruster combustion chambers and nozzles are manufactured with Haynes 25 alloy and the thrusters used storable monopropellant hydrazine. During the atmospheric reentry of thruster pieces at high velocity, the Haynes 25 alloy is submitted to high temperatures in an extreme environment with atomic oxygen. This is why the high temperature oxidation of Haynes 25 was studied, in air plasma conditions in the temperature range 1000–1700 K. Moreover, as emissivity is an important parameter to know for the heat transfer, the spectral directional emissivity was measured on several samples surfaces: pristine, pre-oxidized in air plasma and in situ oxidized in air. The high temperature oxidation of Haynes 25 is moderate up to 1500 K and above an important mass loss occurred up to 1700 K (around 40 mg/cm2), that is the determined melting temperature. The emissivity of pristine Haynes 25 is vey low, around 0.20 at 1350 K and it increases with oxidation up to 0.85–0.90 at 1600 K.

An Asymmetrical Mixed Higher-Order Discontinuous Galerkin Time Domain Method for Electromagnetic Scattering from the Plasma Sheath around a Hypersonic Vehicle

The plasma sheath during reentry of hypersonic vehicle is an unmagnetized and weakly ionized nonuniform plasma flow, which causes radio frequency blackout and strong plasma attenuation of electromagnetic wave. The physical properties of the nonuniform plasma flow were obtained using computational fluid dynamics software with unstructured grids. In this study, a detailed computational model was reconstructed with the high-order Lagrange grids for the nonuniform plasma flow region and the high-order Serendipity grids for the homogeneous medium region. In order to calculate the numerical flux between the two types of grids in the discontinuous Galerkin time domain (DGTD) algorithm, an asymmetric high-order element is constructed as a transition unit. Finally, the simulation results in the plasma sphere show that the above method improves the computational accuracy and decreases calculation. The amplitude and scattering about electromagnetic wave in nonuniform plasma flow are clarified in detail. It is suggested that the presented method could be an effective tool for investigating interaction between electromagnetic waves and plasma flow.

Edge-Based Viscous Method for Mixed-Element Node-Centered Finite-Volume Solvers

A novel, efficient, edge-based viscous (EBV) discretization method has been recently developed and implemented in a practical, unstructured-grid, node-centered, finite-volume flow solver. The EBV method is applied to viscous-kernel computations that include evaluations of mean-flow viscous fluxes, turbulence-model and chemistry-model diffusion terms, and the corresponding Jacobian contributions. Initially, the EBV method had been implemented for tetrahedral grids and demonstrated multifold acceleration of all viscous-kernel computations. This paper presents an extension of the EBV method for mixed-element grids. In addition to the primal edges of a given mixed-element grid, virtual edges are introduced to connect cell nodes that are not connected by a primal edge. The EBV method uses an efficient loop over all (primal and virtual) edges and features a compact discretization stencil based on the nearest neighbors. This study verifies the EBV method and assesses its efficiency on mixed-element grids by comparing the EBV solution accuracy and iterative convergence with those of well-established solutions obtained using a cell-based viscous (CBV) discretization method. The EBV solver’s memory footprint is optimized and often smaller than the memory footprint of the CBV solver. An EBV implementation of a nonlinear extension of the Spalart–Allmaras turbulence model, SA-neg-QCR2000, is also presented and verified. The SA-neg-QCR2000 model is used for simulating turbulent corner flows. Multifold speedup is demonstrated for all viscous-kernel computations, resulting in significant reduction of the time to solutions for several benchmark mixed-element-grid computations, including simulations of subsonic flows around a hemisphere–cylinder configuration and a NASA juncture-flow model, a supersonic flow through a long square duct, and a hypersonic, chemically reacting flow around a blunt body.

A Review of Infrasound and Seismic Observations of Sample Return Capsules since the End of the Apollo Era in Anticipation of the OSIRIS-REx Arrival

Advancements in space exploration and sample return technology present a unique opportunity to leverage sample return capsules (SRCs) towards studying atmospheric entry of meteoroids and asteroids. Specifically engineered for the secure transport of valuable extraterrestrial samples from interplanetary space to Earth, SRCs offer unexpected benefits that reach beyond their intended purpose. As SRCs enter the Earth’s atmosphere at hypervelocity, they are analogous to naturally occurring meteoroids and thus, for all intents and purposes, can be considered artificial meteors. Furthermore, SRCs are capable of generating shockwaves upon reaching the lower transitional flow regime, and thus can be detected by strategically positioned geophysical instrumentation. NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) SRC is one of only a handful of artificial objects to re-enter the Earth’s atmosphere from interplanetary space since the end of the Apollo era and it will provide an unprecedented observational opportunity. This review summarizes past infrasound and seismic observational studies of SRC re-entries since the end of the Apollo era and presents their utility towards the better characterization of meteoroid flight through the atmosphere.

Research on aerodynamic shape optimization of reentry vehicle based on hybrid scale multi-fidelity neural network model

The mechanical expanded reentry vehicle has gained significant attention as a reliable solution for shuttle transportation and deep space exploration missions. However, the aerodynamic characteristics of such a reentry vehicle, including high dimensionality, strong nonlinearity, and parameter coupling, pose a challenge in achieving a balance between precision and efficiency in aerodynamic shape design. In this paper, we propose a hybrid scale multi-fidelity neural network (HS-MFNN) model by integrating low-fidelity and high-fidelity models with neural networks. This model is applied to optimize the aerodynamic shape of the reentry vehicle, addressing the challenge. The feasibility of applying the HS-MFNN model was validated through testing using the MBR function. The advantages of the HS-MFNN model were highlighted through a comparison with other models. Subsequently, the model was utilized in the aerodynamic optimization process of the reentry vehicle. The prediction error for the drag coefficient (Cd) was less than 1%, and for the head stagnation heat flux (QO), it was within 6%. Moreover, the computation time was reduced by three orders of magnitude, ensuring both computational accuracy and efficiency. After optimization, the Cd increased by 5.08%, while the QO decreased by 8.62%. These improvements demonstrate that the use of the HS-MFNN model significantly enhances the aerodynamic performance of the reentry vehicle. Consequently, the HS-MFNN model exhibits great potential for fast and efficient optimization processes.

Aerothermodynamic analysis and rear wake assessment of shock wave interference over blunt leading edge at Mach 6.5

A detailed numerical study of shock-wave interference on a cylindrical blunt leading edge in hypersonic flow is carried out to reveal the effect of shock-shock interaction on peak heating and blunt body aerodynamics. This study is unique in that it examines the effect of interactions on rear wake formation and aerodynamic forces acting on the blunt body. Six different shock wave interference patterns described by Edney are studied for a freestream Mach number of 6.5. Compressible Reynolds-averaged Navier–Stokes equations are solved using finite volume method to obtain accurate prediction of the flowfield and aerodynamic loads. Hugoniot jump conditions are imposed in the inlet boundary to realize oblique shock of desired strength to interact with the detached shock at specific location. Numerical predictions are in good agreement with reported experimental measurements. The results obtained in this study reveals that the type of shock-shock interaction pattern can significantly alter the characteristics of the rear wake. Comparisons to undisturbed flow conditions reveal that Type II to VI interactions lead to an increase in wake size, whereas Type I interaction shows a marginal reduction. These changes in wake size are attributed to modifications in the forebody boundary layer induced by the shock-shock interactions. In the case of Type I interaction, however, the transmitted wave interacting with the rear wake is found to be responsible for the marginal reduction in wake size. This study also shows that changes to the rear wake structure caused by the change in interaction type can affect aerodynamic loads. Type VI interaction recorded a maximum drag coefficient of 2.96, whereas Type IV interaction yielded a maximum lift coefficient of 0.992. These findings demonstrate the potential for dynamically adjusting the control forces of a flying body by manipulating shock interference.

Large-eddy simulation of unsteady flows past a spiked body

Unsteady flows past a spiked body are investigated numerically with wall-resolved large-eddy simulation (LES). The inflow features a Mach number of Ma=2.21 and a Reynolds number of Re=1.2×105. The ratio of the spike length to the blunt body diameter is L/D=1.0. A comparative study of three meshes of different grid resolutions has been conducted by assessing their predictive accuracies and associated subgrid-scale effects. The LES results obtained based on three meshes are compared with the experimental and numerical data found in the literature. A proper orthogonal decomposition (POD) analysis has been conducted based on the pressure and axial velocity fluctuations to investigate turbulence structures. It is observed that the turbulence structures corresponding to the first four POD modes are the most energetic. Furthermore, it is seen that the dominant recirculation zone along the spike in a pulsation cycle can be reconstructed based on the first two POD modes of axial velocity fluctuations. The physical mechanisms of the collapse and inflation processes of the pulsation cycle are investigated based on a detailed transient analysis of fine-resolution LES data. The temporal evolution of vortices and shock waves are investigated. An interesting characteristic Z-shaped trajectory of the instantaneous flow pattern is observed. It is discovered that the pulsation cycle is dominated by the pressure differences between the recirculation zone and two high-pressure regions immediately in front of the cylinder face and near the spike tip.

Geochemical evaluation of cosmic spherules collected from the Central Indian Ocean Basin

Micrometeorites (MMs) significantly contribute to the extraterrestrial material the Earth receives and represent a broader range of precursors than known meteorites. Low sedimentation rates prevalent in the deep-sea regions far away from land provide a unique opportunity for collecting MMs from these least disturbed regions. In the present study, we have studied 305 cosmic spherules recovered from the Central Indian Ocean Basin (CIOB); that have undergone melting during hypervelocity entry into the Earth's atmosphere. During the atmospheric entry, primary signatures of MMs are lost depending upon the extent of heating, complicating the identification of the parent body. Nevertheless, we have tried to relate these cosmic spherules to their respective parent bodies based on elemental ratios present in them, considering atmospheric ablative losses of various elements. The chemical analyses indicate that many deep-sea cosmic spherules are linked to carbonaceous chondrites. Around 239 porphyritic olivines (PO), 42 relict olivines are studied for their textural development and composition during recrystallisation during atmospheric entry. Thirty-zoned olivines are analysed from rim to core to understand various elements behaviour during atmospheric entry. Seawater plays a vital role in eroding these cosmic spherules material, and its effect is also discussed. As most of the recent micrometeorite collections focus on the polar region, these deep-sea spherules will significantly add to the information about the extraterrestrial matter reaching the Earth.

In-situ construction of oxidation resistant porous Mo4.8Si3C0.6/SiC(rGO) composite PDCs served as thermal insulation components of hypersonic vehicles

Actualization of well-balanced high porosity with simultaneous increase in hardness/fracture toughness for thermal insulation composites in hypersonic aerospace vehicle components is always of great challenge. Considering significant toughening effect of unique Mo4.8Si3C0.6-SiC composites microstructure, an agile strategy is proposed to prepare porous Mo4.8Si3C0.6/SiC(rGO) polymer-derived ceramics (PDCs) via re-pyrolysis of ball-milling-induced MoSi2-SiC(rGO)p/polycarbosilane-vinyltriethoxysilane-graphene oxide (PVG) precursors blends with polystyrene (PS) as pore-forming agent. In-situ formed Mo4.8Si3C0.6-β-SiC nanocrystals, possessing eminent mechanical properties and good compatibility with SiOxCy/Cfree, can significantly strengthen interface bonding and increase disorder of ceramic network. Such effective hindrance to crack propagation moderates the inherent brittleness while retaining high hardness of SiC PDCs. Moreover, dense Mo4.8Si3C0.6-β-SiC/SiOxCy/Cfree(rGO) framework, with spontaneous regular pore structure, well balances loading/thermal insulation capacity. Particularly, samples with 10 wt.% PS exhibit outstanding mechanical performances (hardness: 5.10 GPa; fracture toughness: 2.24 MPa·m1/2; compressive strength: 58.15 MPa) and low thermal conductivity (0.8427 W·m-1·K-1). As demonstrated, products remain decent structural integrity after ablation of butane blowtorch flame for 1-20 min. The synergy oxidation with fast response of Mo4.8Si3C0.6 and durability of β-SiC facilitates great anti-oxidation ability, opening up manufacture of SiC-based composites for thermal protection system (TPS) of hypersonic vehicles and re-entry spacecraft with ultra-high speed.