This volume is a compilation of the research presented at the International Asteroid Day workshop which was celebrated at Barcelona on June 30th, 2015. The proceedings discuss the beginning of a new era in the study and exploration of the solar system’s minor bodies. International Asteroid Day commemorates the Tunguska event of June 30th, 1908. The workshop’s goal was to promote the importance of dealing proactively with impact hazards from space. Multidisciplinary experts contributed to this discussion by describing the nature of comets and asteroids along with their offspring, meteoroids. New missions to return material samples of asteroids back to Earth such as Osiris-REx and Hayabusa 2, as well as projects like AIM and DART which will test impact deflection techniques for Potentially Hazardous Asteroids encounters were also covered. The proceedings include both an outreach level to popularize impact hazards and a scientific character which covers the latest knowledge on these topics, as well as offering proposals of promising new techniques that will help gain new insights of the properties of these challenging bodies by studying meteoroids and meteorites. Asteroids, comets, meteoroids and meteorites are introduced with descriptions of their nature, origin, and solar system pathways.

The United States spends approximately $4 million each year searching for near-Earth objects (NEOs). The objective is to detect those that may collide with Earth. The majority of this funding supports the operation of several observatories that scan the sky searching for NEOs. This, however, is insufficient in detecting the majority of NEOs that may present a tangible threat to humanity. A significantly smaller amount of funding supports ways to protect the Earth from such a potential collision or "mitigation." In 2005, a Congressional mandate called for NASA to detect 90 percent of NEOs with diameters of 140 meters of greater by 2020. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies identifies the need for detection of objects as small as 30 to 50 meters as these can be highly destructive. The book explores four main types of mitigation including civil defense, "slow push" or "pull" methods, kinetic impactors and nuclear explosions. It also asserts that responding effectively to hazards posed by NEOs requires national and international cooperation. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies is a useful guide for scientists, astronomers, policy makers and engineers.

It is known that large asteroids and comets can collide with the Earth with severe consequences. Although the chances of a collision in a person's lifetime are small, collisions are a random process and could occur at any time. This book collects the latest thoughts and ideas of scientists concerned with mitigating the threat of hazardous asteroids and comets. It reviews current knowledge of the population of potential colliders, including their numbers, locations, orbits, and how warning times might be improved. The structural properties and composition of their interiors and surfaces are reviewed, and their orbital response to the application of pulses of energy is discussed. Difficulties of operating in space near, or on the surface of, very low mass objects are examined. The book concludes with a discussion of the problems faced in communicating the nature of the impact hazard to the public.

The United States is currently the only country with an active, government-sponsored effort to detect and track potentially hazardous near-Earth objects (NEOs). Congress has mandated that NASA detect and track 90 percent of NEOs that are 1 kilometer in diameter or larger. These objects represent a great potential hazard to life on Earth and could cause global destruction. NASA is close to accomplishing this goal. Congress has more recently mandated that by 2020 NASA should detect and track 90 percent of NEOs that are 140 meters in diameter or larger, a category of objects that is generally recognized to represent a very significant threat to life on Earth if they strike in or near urban areas. Achieving this goal may require the building of one or more additional observatories, possibly including a space-based observatory. Congress directed NASA to ask the National Research Council to review NASA's near-Earth object programs. This interim report addresses some of the issues associated with the survey and detection of NEOs. The final report will contain findings and recommendations for survey and detection, characterization, and mitigation of near-Earth objects based on an integrated assessment of the problem.

In the vast expanse of the cosmos, celestial bodies journey through space, their paths occasionally crossing with our own planet Earth. Among these wanderers are asteroids, mysterious remnants of our solar system's formation that can pose potential threats to our world. Throughout history, Earth has endured the impact of asteroids, leaving lasting marks on our planet's landscape and shaping the course of evolution. Today, as we delve deeper into the realm of space exploration, understanding and mitigating the dangers posed by these wandering rocks have become crucial endeavors. "Asteroid Collision: Threats and Solutions" delves into the intriguing and thoughtprovoking realm of asteroids and the potential risks they pose to Earth. This book is an exploration into the fascinating world of space science, planetary defense, and humanity's quest to safeguard our planet and its inhabitants from potential impact events. As we traverse the pages of this book, we embark on a journey through the formation of our solar system and the genesis of these celestial hazards. We delve into the science behind asteroids, their classifications, and how their paths could intersect with ours. From the catastrophic impact events of the past to the future collision scenarios we may face, we delve into the science of asteroid impacts and their potential consequences. With an indepth analysis of asteroid detection and monitoring techniques, we unravel the cuttingedge technologies and space missions that pave the way for early warning systems and preparedness strategies. From telescopes that peer into the depths of space to spacecraft that journey to distant asteroids, we discover the ingenuity of human ingenuity in deciphering the secrets of the cosmos. The book examines the innovative strategies to divert and mitigate asteroid threats, from theoretical models to practical missions, revealing how science and technology join forces to protect our planet from potential cosmic calamities. It explores the international collaboration and global networks that unite nations in their shared responsibility to safeguard Earth from celestial impacts. As we gaze upward and outward, contemplating the mysteries of the universe, we also turn our attention to the ethical and legal considerations of planetary defense. Questions of responsibility, transparency, and international protocols are explored as we endeavor to create a unified front in safeguarding humanity's future. "Asteroid Collision: Threats and Solutions" is not just a book of knowledge; it is a call to action. It is an invitation to explore the unknown, to embrace the wonders of our universe, and to unite in protecting the fragile oasis we call home. Our collective journey to understand, prepare, and respond to potential asteroid threats symbolizes the human spirit of exploration and resilience. This book aims to inspire scientists, astronomers, policymakers, and the general public alike to engage in planetary defense efforts. It is a testament to the power of knowledge and collaboration, reminding us that together, we can navigate the challenges that lie beyond the stars. Let us embark on this cosmic voyage with curiosity and determination, driven by the desire to secure a safer future for our planet and generations yet to come. Welcome to "Asteroid Collision: Threats and Solutions."

The possibility of asteroid and comet impacts on Earth has received significant recent media and scientific attention. Still, there are many outstanding questions about the correct response once a potentially hazardous object (PHO) is found. Nuclear munitions are often suggested as a deflection mechanism because they have a high internal energy per unit launch mass. However, major uncertainties remain about the use of nuclear munitions for hazard mitigation. There are large uncertainties in a PHO's physical response to a strong deflection or dispersion impulse like that delivered by nuclear munitions. Objects smaller than 100 m may be solid, and objects at all sizes may be 'rubble piles' with large porosities and little strength. Objects with these different properties would respond very differently, so the effects of object properties must be accounted for. Recent ground-based observations and missions to asteroids and comets have improved the planetary science community's understanding of these objects. Computational power and simulation capabilities have improved such that it is possible to numerically model the hazard mitigation problem from first principles. Before we know that explosive yield Y at height h or depth -h from the target surface will produce a momentum change in or dispersion of a PHO, we must quantify energy deposition into the system of particles that make up the PHO. Here we present the initial results of a parameter study in which we model the efficiency of energy deposition from a stand-off nuclear burst onto targets made of PHO constituent materials.

This book describes the complexity of impact hazards associated with asteroids and comets. The challenge in this regard lies in the heterogeneous nature of these bodies that endanger our planet, which is why we are conducting new experiments to better understand their unique physicochemical properties. Several generations of astronomers have tracked and mapped the orbits of asteroids and comets over the past few centuries, and telescopic surveys have only begun to discover “new” interstellar objects. In addition, cutting-edge software allow our computers to combine the orbits of these elusive bodies to study how they evolve over time and seek to match asteroid complexes as fragments of asteroidal and cometary disruptions. Impact hazards represent one of the greatest threats to the survival of human beings in the medium term. Geological studies show that the stratigraphic record holds clear geological evidence of these rare but transcendental encounters in the history of life on our planet. The study and quantification of past catastrophes can give us clues to face future challenges in the form of potential impacts. Further, it would be illogical to assume that Earth’s interaction with space is limited to major impacts. Every night, Earth is struck by millions of particles, and dozens of meteor showers occur around the globe every year. The study of lake and ocean sediments reveals the magnitude of the continuous contribution of interplanetary matter reaching Earth: roughly 100,000 tons per year. Accordingly, the goal of this book is to underscore the need for society-wide awareness of the dangers associated with asteroid and comet impacts, on the basis of scientific evidence and with no intention of sparking alarmism. After all, we ourselves may only be the fruit of an opportunity given to mammals sixty-five million years ago to evolve after the conflagration that would be the downfall of the dinosaurs. If we have learned to read Earth’s geological history, we should consider ourselves a very fortunate species, and its teachings should equip us to face this problem. The also book emphasizes the role of space missions to gain insights on these bodies, particularly describing the relevance of the DART (NASA) and Hera (ESA) missions to deflect and study Dimorphos, respectively, the small satellite of the Didymos binary asteroid.