Hazardous Asteroids Research Articles

Near-Earth Objects (NEO) and other current space threats

The subject of the study are space threats – Near-Earth Objects (NEO) and Potentially Hazardous Asteroids (PHA). The research methods employed in this article included the classic theoretical methods used in security sciences and a practical method – a quantitative study of social media. At present, space threat studies aim to resolve the terminological confusion related to NEOs, determine currently and potentially hazardous space objects and estimate the potential threats they could cause. Another expected result of the research is to present two literature methods for estimating NEO threats, the Palermo and Torino scales. The practical result is to evaluate public mood regarding NEO threats. Studies have shown that certain active space objects are capable of reaching the Earth's surface or impacting human-made in-space objects and devices, such as communication satellites. Should it happen, it could cause substantial social damage and destabilise state security, particularly if elements of critical infrastructure of the state were to be affected. Continuous monitoring of NEOs may play a central role in the provision of security. Furthermore, the public should be kept abreast of the threats.

Prolate Body Disruption by Earth at Near Flyby: Possible Scenarios

In this paper, we discuss the possible disruption of a prolate ellipsoidal small body by the Earth’s tidal forces during a close flyby. An exact expression for the stress tensor under the action of gravity, rotation, and tidal forces is obtained using the analytical solution of the elastic problem. Constraints for the critical distance are derived taking into account the size, shape, density, mechanical properties (material strength and Poisson ratio), rotation, and two variants of the body orientation. Asteroid 433 Eros is considered as a case study. The results are important for methods for assessing the asteroid hazard of near-Earth objects (NEO) and the evolution of terrestrial planets.

Laser Simulations of the Destructive Impact of Nuclear Explosions on Hazardous Asteroids

Laser Simulations of the Destructive Impact of Nuclear Explosions on Hazardous Asteroids

Study on observation simulation for space-based potentially hazardous asteroids warning mission on Earth trailing heliocentric orbit

Study on observation simulation for space-based potentially hazardous asteroids warning mission on Earth trailing heliocentric orbit

On the design of a space telescope orbit around the Sun–Venus [formula omitted] point

In this study, the choice of a nominal space telescope orbit in the vicinity of the Sun–Venus L2 libration point is discussed from the viewpoint of illumination conditions and station-keeping costs. Such a location for the space telescope is especially appealing for the observation of potentially hazardous asteroids approaching the Earth from the daytime side of the sky. In contrast to the case of a telescope placed near the Sun–Earth L1 point, a significantly longer warning time can be achieved. Moreover, a Lissajous-type quasi-periodic orbit can be selected so that a predefined percentage of the orbit is shadowed. When a nominal orbit is allowed to be permanently sunlit, a large halo orbit is preferred due to the lower station-keeping cost. For two sets of unstable halo and Lissajous orbits, the station-keeping cost is evaluated by conducting Monte Carlo simulations in the ephemeris model of motion. Two modifications of the target point station-keeping technique are examined: the X-axis control and the 3-axis control. The simulation scenario includes orbit insertion and navigation errors, impulse execution errors, and constraints on the minimum imparted Δv. Dependence of the station-keeping cost on orbit insertion and navigation errors is analyzed. Some of the large halo orbits appear to be linearly stable. The corresponding central manifold location in the phase space is determined, which makes a simple targeting strategy possible.

Calculation and Research of Space-Temporal Characteristics of Attack Abrases of Asteroids by Orbital Means

A development of work to combat the asteroid hazard requires construction and study of areas of outer space in which moving spacecraft-interceptors can affect asteroids. In this paper, such areas are called attack lines, the spatio-temporal characteristics of which depend on the parameters of the asteroid’s orbits and the phase coordinates of the nodal points. At these points the trajectory intersects the asteroids and the orbital planes of the spacecraft-interceptors. In the case of the impact of spacecraft-interceptors on asteroids at nodal points, the study of the spatio-temporal characteristics of the lines of attack, taking into account restrictions on the relative speeds between asteroids and spacecraft-interceptors, is of particular importance. Building and analyzing the corresponding zones of reverse reach are suggested.
 In the article, the developed models include a simulation model, using which random angles between the projections of the velocity vectors of asteroids on a plane of the orbits of spacecraft-interceptors and the current directions on the hodographs of their velocity vectors at nodal points, as well as an analytical model for estimating the spatio-temporal characteristics of boundaries are simulated attacks of asteroids, including: the radii of their external and internal boundaries for certain values of the latitude arguments and arrival time of spacecraft-interceptors at modal points.
 Testing these models and the corresponding characteristics of the attack lines were carries out during computational experiments on two cyclic modeling of the angles between the projections of the velocity vectors of asteroids on the plane of the orbits of interceptor spacecraft and the current directions on the hodographs of their velocity vectors at nodal points. The results obtained made it possible to verify and validate the developed models, on the basis of which a conclusion was drawn about the required degree of their applicability. In the paper also a procedure for estimating the parameters of attack lines, depending on the values of the arguments of the latitudes of interceptor spacecraft and their altitudes above the Earth's surface is proposed. At the same time, an approach is substantiated for estimating the spatio-temporal characteristics of the boundaries of attack of asteroids by spacecraft-interceptors for any inside the planar parameters of their orbits.

Shape model and spin-state analysis of PHA contact binary (85990) 1999 JV6 from combined radar and optical observations

Context.The potentially hazardous asteroid (85990) 1999 JV6 has been a target of previously published thermal-infrared observations and optical photometry. It has been identified as a promising candidate for possible Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect detection.Aims.The YORP effect is a small thermal-radiation torque considered to be a key factor in spin-state evolution of small Solar System bodies. In order to detect YORP on 1999 JV6 we developed a detailed shape model and analysed the spin-state using both optical and radar observations.Methods.For 1999 JV6, we collected optical photometry between 2007 and 2016. Additionally, we obtained radar echo-power spectra and imaging observations with Arecibo and Goldstone planetary radar facilities in 2015, 2016, and 2017. We combined our data with published optical photometry to develop a robust physical model.Results.We determine that the rotation pole resides at negative latitudes in an area with a 5° radius close to the south ecliptic pole. The refined sidereal rotation period is 6.536787 ± 0.000007 h. The radar images are best reproduced with a bilobed shape model. Both lobes of 1999 JV6 can be represented as oblate ellipsoids with a smaller, more spherical component resting at the end of a larger, more elongated component. While contact binaries appear to be abundant in the near-Earth population, there are only a few published shape models for asteroids in this particular configuration. By combining the radar-derived shape model with optical light curves we determine a constant-period solution that fits all available data well. Using light-curve data alone we determine an upper limit for YORP of 8.5 × 10−8rad day−2.Conclusions.The bifurcated shape of 1999 JV6 might be a result of two ellipsoidal components gently merging with each other, or a deformation of a rubble pile with a weak-tensile-strength core due to spin-up. The physical model of 1999 JV6 presented here will enable future studies of contact binary asteroid formation and evolution.

Influence of non-gravitational effects on the orbits of a few potentially hazardous asteroids

Observations of Mars and Venus-crossing asteroid (5131) 1990 BG and the near-Earth approaching asteroid (13553) Masaakikoyama 1992 JE were made using ZA-320M and MTM-500M telescopes of the Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo. Evolution of their orbits was investigated taking into account the Yarkovsky effect, as well as the solar radiation pressure influence for various values of albedo of these objects. The obtained results were summarized and compared with results of the Yarkovsky effect for (308635) 2005 YU55, (418094) 2007 WV4, 2017 VR12 and (276033) 2002 AJ129, which had been studied earlier. Conclusions about non-gravitational effects on the motion of potentially hazardous asteroids were drawn.

Diversion of an Asteroid Using a Transversal Thruster

The diversion of a hazardous asteroid on a collisional trajectory with the Earth using a transversal thruster is considered. The thruster could be either mounted on the asteroid or used as a “gravitational tractor”. The aim of the study is to establish the fundamental possibility (or impossibility) of diverting an asteroid to a safe distance over a time of order months or years. This is acceptable, since the impact of an asteroid with a diameter of order 100 m on the Earth just after its discovery is very improbable. A model formulation of the problem in which the thruster provides a constant transversal acceleration of the asteroid is used. The corresponding Euler-type equations are transformed using the method of previous averaging. These equations are solved using the method of “slow time” power series, and the adequacy of the solutions over time scales of decades is demonstrated. An asteroid up to 55 m in diameter can be deflected over a year using a 1 N thruster. Asteroids with diameters up to 50 m can be diverted over a month, and with diameters up to 150 m over a year, using a 20 N thruster. Moving larger asteroids requires more time or more powerful engines.

Astrometric and photometric observations of the potentially hazardous asteroid 2017 VR12

Observations of potentially hazardous asteroid 2017 VR12 during its close approach to the Earth were made at Pulkovo Observatory via ZA-320M telescope at the end of February and the beginning of March 2018. Orbital elements of the asteroid were improved basing on the obtained astrometric data. The orbital evolution was studied and the influence of non-gravitational effects was estimated. The axial rotation period of the asteroid was determined from photometric data.

Mechanical properties of particles from the surface of asteroid 25143 Itokawa

Aims.Asteroids have been exposed to impacts since their formation, and as a consequence their surfaces are covered by small particles, pebbles, and boulders. The Japanese JAXA/ISAS Hayabusa mission collected micron-sized particles from the regolith of asteroid 25143 Itokawa. The study in terrestrial laboratories of these particles provides a scientific opportunity as their physical properties can be compared with those characteristic of chondritic meteorites that are often considered proxies of the building materials of potentially hazardous asteroids (PHAs).Methods.Here we present the results from a study of the mechanical properties of three of these particles using a precise technique called nanoindentation. The derived results are compared with those obtained via a methodology similar to that used for the Chelyabinsk meteorite.Results.The reduced Young’s modulus values obtained for the Itokawa samples are higher than those measured for the Chelyabinsk chondrite, so these specific particles of asteroid regolith are more compacted than the minerals forming the particular LL chondrite associated with PHAs. This might be a natural consequence of particles surviving long exposure times on the surface of a (near-Earth asteroid) NEA. The Double Asteroid Redirection Test (DART) mission plans to excavate a crater in the surface of the (65803) Didymos satellite. Our results suggest that excavating a crater with a kinetic impactor in an area of significant fine-grained regolith will increase the momentum transfer. As this will facilitate the release of particles carrying target mass in the opposite direction to the movement of the projectile, there is no need to grind up the target during the mechanical excavation phase.

The Possibility of Harmless Destruction of an Asteroid Threatening the Earth

One possible means of counteraction against a hazardous asteroid is discussed: destruction of the object with a nuclear device during an earlier encounter with the Earth. This is feasible, since virtually all hazardous asteroids appear in near-Earth space several times before they hit the Earth. Computations show that this method is effective and essentially harmless if certain conditions are satisfied. Two possibilities are acceptable. In the first, a spacecraft overtakes the asteroid in a heliocentric orbit. In the second, the asteroid overtakes the spacecraft, which demands a substantially lower characteristic geocentric velocity for the spacecraft. This method for eliminating this cosmic threat is reasonable in two cases: when it is not possible to achieve a soft departure of the object from the collision orbit, and when the object continuously returns to the Earth. A soft departure from a collision orbit can be required multiple times, whereas the destruction of such an object must occur only once.

Yarkovsky effect detection and updated impact hazard assessment for near-Earth asteroid (410777) 2009 FD

Aims. Near-Earth asteroid (410777) 2009 FD is a potentially hazardous asteroid with possible (though unlikely) impacts on Earth at the end of the twenty-second century. The astrometry collected during the 2019 apparition provides information on the trajectory of (410777) by constraining the Yarkovsky effect, which is the main source of uncertainty for future predictions, and improving the impact hazard assessment. Methods. We included the Yarkovsky effect in the force model and estimated its magnitude from the fit to the optical and radar astrometric data of (410777). We performed the hazard assessment for (410777) over 200 years using two independent approaches: the NEODyS group adopted a generalisation of the Line Of Variations method in a seven-dimensional space, and the JPL team used the Multi-Layer Clustered Sampling technique. Results. We obtain a 4σ detection of the Yarkovsky effect acting on (410777), which corresponds to a semimajor axis drift of (3.8 ± 0.9) × 10−3 au Myr−1. In the hazard results of both teams, the main impact possibility in 2185 is ruled out and the only remaining one is in 2190, but with a probability lower than 10−8.

Assessing the risk of potentially hazardous asteroids through mean motion resonances analyses

Planetary research on the Near-Earth objects (NEOs) has always been a relevant and meaningful topic. Investigating the dynamical behaviour and physical properties of NEOs is significant for understanding the evolution and origin of the solar system. On the other hand, the study of some of these NEOs is crucial for Earth inhabitants because they experience sufficiently close approaches to our planet and are large enough to cause significant damage in the event of an impact. Potentially hazardous asteroids (PHAs) are those having a minimum orbital intersection distance (MOID) with Earth of less than 0.05 AU and an absolute magnitude of 22 or brighter; some of them could impact the Earth within the next century, causing damage on a regional or larger scale. About 1900 PHAs are currently known, of them only 20 to 30 percent have been found, from estimated amounts to $4700\pm 1500$ . They have orbits which could bring them to collide with our planet except those excluded by protective resonance. Because mean motion resonances can protect the planet-crossing objects from disruptive close encounters or collision with the planets, they provide us a practical approach to assess and mitigate the risk of some PHAs. We introduce a numerical technique STD criterion to seek the PHAs in resonance conveniently. A systematic survey of all the discovered PHAs in mean motion resonance with Earth is presented. The resonant configurations of some PHAs in different orders are depicted to illustrate our results further. We identified 176 PHAs (about 9.3% of discovered PHAs) trapped in resonances with Earth, 70 PHAs among them are currently in resonances while others will be captured into particular resonant configurations. Theoretically, the risk of these 176 PHAs is lower and can be neglected for the 22 PHAs in the long-term stable resonant state. We provide a new approach to assess the risk of PHAs. Our conclusions may provide a significant reference for the space missions devoted to PHAs. We indicate some PHAs in co-orbit resonance with Earth and resonances characterized by asymmetric libration. Our findings also highlight some essential properties of resonant dynamics and provide a number of real examples for the research on resonant configurations and resonance capture.

Time and Phase Resolved Optical Spectra of Potentially Hazardous Asteroid 2014 JO25

Abstract The asteroid 2014 JO25, considered to be potentially hazardous by the Minor Planet Center, was spectroscopically followed during its close-Earth encounter on 2017 April 19 and 20. The spectra of the asteroid were taken with the low-resolution spectrograph (LISA), mounted on the 1.2 m telescope at the Mount Abu Infrared Observatory, India. Coming from a region close to the Hungaria population of asteroids, this asteroid follows a comet-like orbit with a relatively high inclination and large eccentricity. Hence, we carried out optical spectroscopic observations of the asteroid to look for comet-like molecular emissions or outbursts. However, the asteroid showed a featureless spectrum, devoid of any comet-like features. The light curve of the asteroid was analyzed using V-band magnitudes derived from the spectra and the most likely solution for the rotation of the asteroid was obtained. The absolute magnitude H and the slope parameter G were determined for the asteroid in the V filter band using the IAU accepted standard two-parameter H–G model. A peculiar, rarely found result from these observations is its phase bluing trend. The relative B–V color index seems to decrease with increasing phase angle, which indicates a phase bluing trend. Such trends have seldom been reported in the literature. However, phase reddening in asteroids is very common. The asymmetry parameter g and the single-scattering albedo w were estimated for the asteroid by fitting the Hapke phase function to the observed data. The asteroid shows a relatively large value for the single-scattering albedo and a highly back-scattering surface.

Comparison of different methods for preventive destruction of a hazardous asteroid

This paper deals with one of the methods asteroid hazard mitigation. The preventive destruction of a hazardous asteroid during the previous close encounter before its predicted collision is considered. Two variants of the explosion are considered: in the first case a projectile overtakes an asteroid; in the second one the situation is contrary. The second way requires significantly lower velocity of spacecraft delivery. On the other hand, it loses to the first way, since the number of fragments falling to the Earth is about an order of magnitude larger. However, with a more careful approach (non-isotropic explosion), this unfavorable factor can be likely reduced.

Risk-Based Approach to Prevention of Asteroid and Comet Hazard. Mathe-matical Model of Risk

Risk-Based Approach to Prevention of Asteroid and Comet Hazard. Mathe-matical Model of Risk

Risk-Informed Approach to Mitigation of Asteroid and Comet Impact Hazard. Astronomical Aspects

Risk-Informed Approach to Mitigation of Asteroid and Comet Impact Hazard. Astronomical Aspects

Waiting to make an impact: a probable excess of near-Earth asteroids in 2018 LA-like orbits

Context.The discovery and tracking of 2018 LA marks only the third instance in history that the parent body of a fireball has been identified before its eventual disintegration in our atmosphere. The subsequent recovery of meteorites from 2018 LA was only the second time materials from outer space that reached the ground could be linked with certitude to a particular minor body. However, meteoroids like 2018 LA and its forerunners, 2008 TC3and 2014 AA, are perhaps fragments of larger members of the near-Earth object (NEO) population. As the processes leading to the production of such fragments are unlikely to spawn just one meteoroid per event, it is important to identify putative siblings and plausible candidates from which the observed meteoroids might have originated.Aims.Here, we study the pre-impact orbital evolution of 2018 LA to place this meteoroid within the dynamical context of other NEOs that follow similar trajectories.Methods.Our statistical analyses are based on the results of directN-body calculations that use the latest orbit determinations and include perturbations by the eight major planets, the Moon, the barycentre of the Pluto–Charon system, and the three largest asteroids. A state-of-the-art NEO orbit model was used to interpret our findings and a randomization test was applied to estimate their statistical significance.Results.We find a statistically significant excess of NEOs in 2018 LA-like orbits; among these objects, we find one impactor, 2018 LA, and the fourth closest known passer-by, 2018 UA. A possible connection with theχ-Scorpiids meteor shower is also discussed. The largest known NEO with an orbit similar to that of 2018 LA is the potentially hazardous asteroid (454100) 2013 BO73and we speculate that they both originate from a common precursor via a collisional cascade.Conclusions.Future spectroscopic observations of 454100 and other NEOs in similar orbits may confirm or deny a possible physical relationship with 2018 LA.

Анализ точностей определения орбит опасных астероидов моделированием оптических измерений космической системы «Небосвод»

Анализ точностей определения орбит опасных астероидов моделированием оптических измерений космической системы «Небосвод»