The Experts below are selected from a list of 1929 Experts worldwide ranked by ideXlab platform
Wei Zheng - One of the best experts on this subject based on the ideXlab platform.
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enhanced kinetic impactor for deflecting large potentially hazardous asteroids via maneuvering space rocks
2020Co-Authors: Yirui Wang, Youliang Wang, Binghong Zhou, Wei ZhengAbstract:Asteroid impacts pose a major threat to all life on Earth. The age of the dinosaurs was abruptly ended by a 10-km-diameter asteroid. Currently, a nuclear device is the only means of deflecting large Potentially Hazardous Asteroids (PHAs) away from an Earth-impacting trajectory. The Enhanced Kinetic Impactor (EKI) concept is proposed to deflect large PHAs via maneuvering space rocks. First, an Unmanned Spacecraft is launched to rendezvous with an intermediate Near-Earth Asteroid (NEA). Then, more than one hundred tons of rocks are collected from the NEA as the EKI. The NEA can also be captured as the EKI if the NEA is very small. Finally, the EKI is maneuvered to impact the PHA at a high speed, resulting in a significant deflection of the PHA. For example, to deflect Apophis, as much as 200 t of rocks could be collected from a NEA as the EKI based on existing engineering capabilities. The EKI can produce a velocity increment (∆v) of 39.81 mm/s in Apophis, thereby increasing the minimum geocentric distance during the close encounter in 2029 by 1,866.93 km. This mission can be completed in 3.96 years with a propellant cost of 2.98 t. Compared with a classic kinetic impactor, the deflection distance can be increased one order of magnitude. The EKI concept breaks through the limitation of the ground-based launch capability, which can significantly increase the mass of the impactor. We anticipate that our research will be a starting point for efficient planetary defense against large PHAs.
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enhanced kinetic impactor for deflecting large potentially hazardous asteroids via maneuvering space rocks
2019Co-Authors: Yirui Wang, Youliang Wang, Binghong Zhou, Wei ZhengAbstract:Asteroid impacts pose a major threat to all life on Earth. The age of the dinosaurs was abruptly ended by a 10-km-diameter asteroid. Currently, a nuclear device is the only means of deflecting large Potentially Hazardous Asteroids (PHAs) away from an Earth-impacting trajectory. The Enhanced Kinetic Impactor (EKI) concept is proposed to deflect large PHAs via maneuvering space rocks. First, an Unmanned Spacecraft is launched to rendezvous with an intermediate Near-Earth Asteroid (NEA). Then, more than one hundred tons of rocks are collected from the NEA as the EKI. The NEA can also be captured as the EKI if the NEA is very small. Finally, the EKI is maneuvered to impact the PHA at a high speed, resulting in a significant deflection of the PHA. For example, to deflect Apophis, as much as 200 t of rocks could be collected from a NEA as the EKI based on existing engineering capabilities. The EKI can produce a velocity increment (delta-v) of 39.81 mm/s in Apophis, thereby increasing the minimum geocentric distance during the close encounter in 2029 by 1,866.93 km. This mission can be completed in 3.96 years with a propellant cost of 2.98 t. Compared with a classic kinetic impactor, the deflection distance can be increased one order of magnitude. The EKI concept breaks through the limitation of the ground-based launch capability, which can significantly increase the mass of the impactor. We anticipate that our research will be a starting point for efficient planetary defense against large PHAs.
Yirui Wang - One of the best experts on this subject based on the ideXlab platform.
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enhanced kinetic impactor for deflecting large potentially hazardous asteroids via maneuvering space rocks
2020Co-Authors: Yirui Wang, Youliang Wang, Binghong Zhou, Wei ZhengAbstract:Asteroid impacts pose a major threat to all life on Earth. The age of the dinosaurs was abruptly ended by a 10-km-diameter asteroid. Currently, a nuclear device is the only means of deflecting large Potentially Hazardous Asteroids (PHAs) away from an Earth-impacting trajectory. The Enhanced Kinetic Impactor (EKI) concept is proposed to deflect large PHAs via maneuvering space rocks. First, an Unmanned Spacecraft is launched to rendezvous with an intermediate Near-Earth Asteroid (NEA). Then, more than one hundred tons of rocks are collected from the NEA as the EKI. The NEA can also be captured as the EKI if the NEA is very small. Finally, the EKI is maneuvered to impact the PHA at a high speed, resulting in a significant deflection of the PHA. For example, to deflect Apophis, as much as 200 t of rocks could be collected from a NEA as the EKI based on existing engineering capabilities. The EKI can produce a velocity increment (∆v) of 39.81 mm/s in Apophis, thereby increasing the minimum geocentric distance during the close encounter in 2029 by 1,866.93 km. This mission can be completed in 3.96 years with a propellant cost of 2.98 t. Compared with a classic kinetic impactor, the deflection distance can be increased one order of magnitude. The EKI concept breaks through the limitation of the ground-based launch capability, which can significantly increase the mass of the impactor. We anticipate that our research will be a starting point for efficient planetary defense against large PHAs.
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enhanced kinetic impactor for deflecting large potentially hazardous asteroids via maneuvering space rocks
2019Co-Authors: Yirui Wang, Youliang Wang, Binghong Zhou, Wei ZhengAbstract:Asteroid impacts pose a major threat to all life on Earth. The age of the dinosaurs was abruptly ended by a 10-km-diameter asteroid. Currently, a nuclear device is the only means of deflecting large Potentially Hazardous Asteroids (PHAs) away from an Earth-impacting trajectory. The Enhanced Kinetic Impactor (EKI) concept is proposed to deflect large PHAs via maneuvering space rocks. First, an Unmanned Spacecraft is launched to rendezvous with an intermediate Near-Earth Asteroid (NEA). Then, more than one hundred tons of rocks are collected from the NEA as the EKI. The NEA can also be captured as the EKI if the NEA is very small. Finally, the EKI is maneuvered to impact the PHA at a high speed, resulting in a significant deflection of the PHA. For example, to deflect Apophis, as much as 200 t of rocks could be collected from a NEA as the EKI based on existing engineering capabilities. The EKI can produce a velocity increment (delta-v) of 39.81 mm/s in Apophis, thereby increasing the minimum geocentric distance during the close encounter in 2029 by 1,866.93 km. This mission can be completed in 3.96 years with a propellant cost of 2.98 t. Compared with a classic kinetic impactor, the deflection distance can be increased one order of magnitude. The EKI concept breaks through the limitation of the ground-based launch capability, which can significantly increase the mass of the impactor. We anticipate that our research will be a starting point for efficient planetary defense against large PHAs.
Emma A Taylor - One of the best experts on this subject based on the ideXlab platform.
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hypervelocity impact on Spacecraft honeycomb hydrocode simulation and damage laws
2003Co-Authors: Emma A Taylor, Jonathan Glanville, Richard A Clegg, Robert G TurnerAbstract:Spacecraft honeycomb structures provide the primary shielding against meteoroid and debris impact for Unmanned Spacecraft in orbit around the Earth. Hypervelocity impact velocities for Spacecraft in Low Earth Orbit can reach speeds of 15-16 km/s yet, for the particle diameters of interest, experimental test facilities are limited to maximum velocities in the range 7-8 km/s. Previous tests onto aluminium and cadmium facesheets with honeycomb core (or cylindrical equivalent) and composite facesheets with aluminium honeycomb core have identified that the honeycomb core influences the impact process (typically called "channelling"). Tests also identified that the shielding performance was altered under oblique incidence impact. Hydrocode computer simulations can be used to explore the velocity regime beyond the capabilities of existing experimental test facilities. In order to investigate the impact processes on honeycomb and to evaluate damage equation methodologies at velocities beyond the experimental test regime, a simulation programme was defined using the hydrocodes AUTODYN-2D and 3D. First 2D axisymmetric, simulations of normal impact on single and double honeycomb were carried out and compared with published test data. Good agreement was obtained. To model the required geometry, Lagrange, Shell and Smooth Particle Hydrodynamics (SPH) solvers were coupled together. Further 2D simulations were then carried out at velocities of 7, 11 and 14 km/s on two Spacecraft honeycomb structures representative of those used in Unmanned Spacecraft. The ballistic limit was identified and, for impacts above this limit, the post-perforation debris cloud characteristics were calculated by evaluating the momentum recorded on a witness plate or by calculating a momentum pressure function of the post-perforation debris cloud. A honeycomb damage equation, based on the semi-infinite penetration equation, was compared with the simulation results. It shows better agreement with both experimental test results and 2D simulations than the Whipple bumper shield (Christiansen-Cour-Palais) formulation previously applied to honeycomb data, and therefore provides a means to characterise single honeycomb shielding performance as part of Spacecraft design and verification activities. The simulation methodology was extended and two 3D oblique incidence simulations were carried out at 11 km/s. These simulation results were also consistent with the equation predictions. (C) 2003 Published by Elsevier Ltd.
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cost effective honeycomb and multi layer insulation debris shields for Unmanned Spacecraft
2001Co-Authors: Robert J Turner, Emma A Taylor, Anthony J M Mcdonnell, Hedley Stokes, Peter Marriott, J E Wilkinson, David J Catling, Rade Vignjevic, Lucy Berthoud, Michel LambertAbstract:Ways to improve the tolerance of Unmanned Spacecraft to hypervelocity impact are presented. Two new honeycomb and multi-layer insulation (MLI) shields were defined: (1) double honeycomb, and (2) enhanced or toughened MLI (with additional Kevlar 310 and/or Betacloth layers). Following hypervelocity impact testing, a new ballistic limit threshold was defined, based on rear facesheet perforation and witness plate damage characteristics. At 12 km/s, the ballistic limit of single honeycomb was 0.58 mm (aluminium sphere), rising to 0.91 mm for double honeycomb, 1.00 mm for double honeycomb with MLI and 1.17 mm for double honeycomb with toughened MLI. A damage equation, based on the modified Cour-Palais equation with ESA constants, was compared with the data and found to be conservative. The impact angle exponent was increased in order to reduce the equation under-prediction for the oblique incidence data. An equivalent rear wall thickness was defined in order to distinguish between shield types above 7 km/s. The Spacecraft survivability analysis showed that the double honeycomb and toughened MLI significantly reduced the number of perforating particles over the baseline single honeycomb design. The mass increase of these shields is approximately 1.2 kg/m2 for double honeycomb and 0.8 kg/m2 for toughened MLI.
Michel Lambert - One of the best experts on this subject based on the ideXlab platform.
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cost effective honeycomb and multi layer insulation debris shields for Unmanned Spacecraft
2001Co-Authors: Robert J Turner, Emma A Taylor, Anthony J M Mcdonnell, Hedley Stokes, Peter Marriott, J E Wilkinson, David J Catling, Rade Vignjevic, Lucy Berthoud, Michel LambertAbstract:Ways to improve the tolerance of Unmanned Spacecraft to hypervelocity impact are presented. Two new honeycomb and multi-layer insulation (MLI) shields were defined: (1) double honeycomb, and (2) enhanced or toughened MLI (with additional Kevlar 310 and/or Betacloth layers). Following hypervelocity impact testing, a new ballistic limit threshold was defined, based on rear facesheet perforation and witness plate damage characteristics. At 12 km/s, the ballistic limit of single honeycomb was 0.58 mm (aluminium sphere), rising to 0.91 mm for double honeycomb, 1.00 mm for double honeycomb with MLI and 1.17 mm for double honeycomb with toughened MLI. A damage equation, based on the modified Cour-Palais equation with ESA constants, was compared with the data and found to be conservative. The impact angle exponent was increased in order to reduce the equation under-prediction for the oblique incidence data. An equivalent rear wall thickness was defined in order to distinguish between shield types above 7 km/s. The Spacecraft survivability analysis showed that the double honeycomb and toughened MLI significantly reduced the number of perforating particles over the baseline single honeycomb design. The mass increase of these shields is approximately 1.2 kg/m2 for double honeycomb and 0.8 kg/m2 for toughened MLI.
Youliang Wang - One of the best experts on this subject based on the ideXlab platform.
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enhanced kinetic impactor for deflecting large potentially hazardous asteroids via maneuvering space rocks
2020Co-Authors: Yirui Wang, Youliang Wang, Binghong Zhou, Wei ZhengAbstract:Asteroid impacts pose a major threat to all life on Earth. The age of the dinosaurs was abruptly ended by a 10-km-diameter asteroid. Currently, a nuclear device is the only means of deflecting large Potentially Hazardous Asteroids (PHAs) away from an Earth-impacting trajectory. The Enhanced Kinetic Impactor (EKI) concept is proposed to deflect large PHAs via maneuvering space rocks. First, an Unmanned Spacecraft is launched to rendezvous with an intermediate Near-Earth Asteroid (NEA). Then, more than one hundred tons of rocks are collected from the NEA as the EKI. The NEA can also be captured as the EKI if the NEA is very small. Finally, the EKI is maneuvered to impact the PHA at a high speed, resulting in a significant deflection of the PHA. For example, to deflect Apophis, as much as 200 t of rocks could be collected from a NEA as the EKI based on existing engineering capabilities. The EKI can produce a velocity increment (∆v) of 39.81 mm/s in Apophis, thereby increasing the minimum geocentric distance during the close encounter in 2029 by 1,866.93 km. This mission can be completed in 3.96 years with a propellant cost of 2.98 t. Compared with a classic kinetic impactor, the deflection distance can be increased one order of magnitude. The EKI concept breaks through the limitation of the ground-based launch capability, which can significantly increase the mass of the impactor. We anticipate that our research will be a starting point for efficient planetary defense against large PHAs.
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enhanced kinetic impactor for deflecting large potentially hazardous asteroids via maneuvering space rocks
2019Co-Authors: Yirui Wang, Youliang Wang, Binghong Zhou, Wei ZhengAbstract:Asteroid impacts pose a major threat to all life on Earth. The age of the dinosaurs was abruptly ended by a 10-km-diameter asteroid. Currently, a nuclear device is the only means of deflecting large Potentially Hazardous Asteroids (PHAs) away from an Earth-impacting trajectory. The Enhanced Kinetic Impactor (EKI) concept is proposed to deflect large PHAs via maneuvering space rocks. First, an Unmanned Spacecraft is launched to rendezvous with an intermediate Near-Earth Asteroid (NEA). Then, more than one hundred tons of rocks are collected from the NEA as the EKI. The NEA can also be captured as the EKI if the NEA is very small. Finally, the EKI is maneuvered to impact the PHA at a high speed, resulting in a significant deflection of the PHA. For example, to deflect Apophis, as much as 200 t of rocks could be collected from a NEA as the EKI based on existing engineering capabilities. The EKI can produce a velocity increment (delta-v) of 39.81 mm/s in Apophis, thereby increasing the minimum geocentric distance during the close encounter in 2029 by 1,866.93 km. This mission can be completed in 3.96 years with a propellant cost of 2.98 t. Compared with a classic kinetic impactor, the deflection distance can be increased one order of magnitude. The EKI concept breaks through the limitation of the ground-based launch capability, which can significantly increase the mass of the impactor. We anticipate that our research will be a starting point for efficient planetary defense against large PHAs.
