A5019210095- Astro and Planetary Science
- Planetary Science and Exploration
- Space Satellite Systems and Control
- Nuclear Issues and Defense
- earthquake and tectonic studies
- Geology and Paleoclimatology Research
- Gamma-ray bursts and supernovae
- Geological and Geochemical Analysis
- Distributed and Parallel Computing Systems
- Laser-induced spectroscopy and plasma
- Isotope Analysis in Ecology
- Radioactive contamination and transfer
- Marine and environmental studies
- Risk and Safety Analysis
- High-pressure geophysics and materials
- Disaster Response and Management
- Technology Assessment and Management
- Earthquake Detection and Analysis
- Biomedical and Engineering Education
- Spacecraft Design and Technology
- Seismology and Earthquake Studies
- Military Strategy and Technology
- Thermal Analysis in Power Transmission
- Gas Dynamics and Kinetic Theory
- Advanced Sensor Technologies Research
Ames Research Center
2011-2024
Columbia University
2023
Johns Hopkins University Applied Physics Laboratory
2021
Arizona State University
2021
SRA International (United States)
2017-2018
A comprehensive asteroid threat assessment requires the quantification of both impact likelihood and resulting consequence across range possible events. This paper presents a probabilistic risk (PAIR) model developed for this purpose. The incorporates published frequency rates with state-of-the-art tools, applied within Monte Carlo framework that generates sets scenarios from uncertain input parameter distributions. Explicit treatment atmospheric entry is included to produce energy...
As asteroids break up during atmospheric entry, they deposit energy that can be seen in flares of light and, if substantial enough, produce damaging blast waves. Analytic models asteroid breakup and deposition processes are needed order to assess potential airburst hazards, enable inferences about properties or physics made from comparisons with observed meteors. This paper presents a fragment-cloud model (FCM) is able represent broad range behaviors the resulting variations ways make it...
During asteroid entry, energy is deposited in the atmosphere through thermal ablation and momentum-loss due to aerodynamic drag. Analytic models of entry breakup physics are used compute deposition, which can then be compared against measured light curves estimate ground damage airburst events. This work assesses compares deposition results from four existing approaches modeling, presents a new model that combines key elements those approaches. The considered include liquid drop or "pancake"...
Asteroid impacts can cause a wide range of damage through multiple potential hazards, from localized blast waves or thermal radiation, to tsunami inundation, global climatic effects. The level risk posed by these hazards depends not only upon their extent and severity, but also the likelihood various ranges. Some consequences may be more moderate very likely, while others unlikely catastrophic. Evaluating involves substantial uncertainties across all aspects problem, including properties...
Abstract We present the results of a fourth planetary defense exercise, focused this time on small near-Earth asteroid (NEA) 2023 DZ2 and conducted during its close approach to Earth in March. The International Asteroid Warning Network (IAWN), with support from NASA's Planetary Defense Coordination Office (PDCO), has been coordinating observational campaigns since 2017 test operational readiness global capabilities. last campaign NEA Apophis, an outcome that exercise was need for short burst...
A high-fidelity approach for simulating the aerothermodynamic environments of meteor entries was developed, which allows commonly assumed heat transfer coefficient 0.1 to be assessed. This model uses chemically reacting computational fluid dynamics (CFD), coupled with radiation transport and surface ablation. Coupled accounts impact on flowfield energy equations, while ablation explicitly models injection products within simulations. For a meteoroid velocity 20 km/s, is shown reduce...
Abstract The destructive power of an impacting asteroid is primarily estimated by knowledge its size. Asteroid 2024 YR4 reached a peak 2032 impact probability with Earth 3%, motivating desire to determine Owing infrared capabilities, JWST uniquely suited for such assessment, especially decameter-scale objects. We used observe and find diameter 60 ± 7 m. This size range corresponds albedo 8%–18%, consistent observation that it S-type (International Warning Network,...
Asteroids populations are highly diverse, ranging from coherent monoliths to loosely bound rubble piles, with a broad range of material and compositional properties. These different structures properties could significantly affect how an asteroid breaks up deposits energy in the atmosphere, much ground damage may occur resulting blast waves. We have previously developed fragment-cloud model (FCM) for assessing atmospheric breakup deposition asteroids striking Earth. The approach represents...
Abstract We describe results of a planetary defense exercise conducted during the close approach to Earth by near-Earth asteroid (99942) Apophis 2020 December–2021 March. The community has been conducting observational campaigns since 2017 test operational readiness global capabilities. These community-led exercises were carried out with support NASA’s Planetary Defense Coordination Office and International Asteroid Warning Network. campaign is third in our series exercises. goal this was...
The Tunguska meteor airburst has been extensively studied and modeled in attempts to deduce its size, properties, impact characteristics. However, most of the existing modeling simulation studies have investigated a small subset cases based on assumptions representative densities, velocities, or other properties. In this study, we use probabilistic asteroid risk model assess entry, burst, ground damage from 50 million Tunguska-scale impacts, covering full range potential impactor are sampled...
Evacuation zone recommendations are determined for potential asteroid impacts. In most impacts on land, the dominant damage mechanism is blast wave. Hurricane evacuations in United States show that average people evacuate to a 1 million risk of fatality level. To achieve equivalent from wave, preliminary estimates everyone within 1–2 psi (≈0.07–0.14 atm or bar) radius should as, even when taking shelter, threshold probably exceeded. From there out 0.4–0.5 radii, seeking shelter basement...
NASA's Probabilistic Asteroid Impact Risk (PAIR) model assesses the likelihood of potential damage for asteroid impact scenarios. Fast-running models are used to capture effects different hazards. This paper looks specifically at local ground hazards, including blast overpressure and thermal radiation damage, large object A sensitivity study is conducted determine which parameters, over what ranges, cause risks become sensitive damage. Two additional with approaches comparison. The...
Abstract Flux and impact angles were calculated for asteroid collisions with Earth the Moon, using latest population models distribution of near-Earth objects (NEOs) precession to determine probabilities. The calculations predict that flux impacts poles is 22% greater than at equator, 55% Moon. Impacts near equator typically have shallower a mode 30° above horizontal. Conversely, are steep close 65°. Our new analysis updates previously published results by Le Feuvre & Wieczorek...
Risk assessment studies of local asteroid hazards traditionally simulate the physics meteors with engineering models tailored to analyze tens-of-millions scenarios. However, these simplified approaches still need solve time-dependent ODEs model entry process and resulting ground damage. With a computational cost O(0.01 CPU.s) per scenario, simulating large numbers potential conditions can take several days on computers. To improve efficiency, we propose in this paper an orthogonal approach...
Assessments of the risk posed by asteroid impacts depend implicitly upon estimates how frequently asteroids different sizes and properties are expected to strike Earth. These impact rates generally based populations near-Earth objects as a function absolute magnitude, which then translated equivalent size frequencies assuming an average albedo. However, this simplified approach neglects broad distribution among given magnitude. In study, we use probabilistic model more rigorously investigate...
A methodology is introduced to optimize and extend the inference of pre-entry size, density, strength, mass asteroids based on observed light curves. In this development study, a genetic algorithm (GA) approach coupled with fragment-cloud model (FCM) efficiently evaluate entry breakup for numerous potential asteroid property combinations determine which case best matches data. FCM produces energy deposition curves assumed conditions, GA finds values these inputs that minimize an objective...
The NASA Advanced Supercomputing (NAS) facility at Ames Research Center has enabled remarkable breakthroughs in the space agency's science and engineering missions. For 30 years, NAS experts have influenced state of art high-performance computing related technologies.