Comets and asteroids are in some sense the fossils of the solar system. They have avoided most of the drastic physical processing that shaped the planets and thus represent more closely the properties of the primordial solar nebula. What processing has taken place is itself of interest in decoding the history of our solar neighborhood. Near-Earth objects are also of interest because one or more large ones have been blamed for the rare but devastating events that caused mass extinctions of species on our planet, as attested by recent excitement over the impending passage of asteroid 1997 XF11. The comets and asteroids whose orbits bring them close to Earth are clearly the most accessible to detailed investigation, both from the ground and from spacecraft. When nature kindly delivers the occasional asteroid to the surface of Earth as a meteorite, we can scrutinize it closely in the laboratory; a great deal of information about primordial chemical composition and primitive processes has been gleaned from such objects. This report reviews the current state of research on near-Earth objects and considers future directions. Attention is paid to the important interplay between ground-based investigations and spaceborne observation or sample collection and return. This is particularly timely since one U.S. spacecraft is already on its way to rendezvous with a near-Earth object, and two others plus a Japanese mission are being readied for launch. In addition to scientific issues, the report considers technologies that would enable further advances in capability and points out the possibilities for including near-Earth objects in any future expansion of human exploration beyond low Earth orbit.

An insider's look at the science of near-Earth comets and asteroids Of all the natural disasters that could befall us, only an Earth impact by a large comet or asteroid has the potential to end civilization in a single blow. Yet these near-Earth objects also offer tantalizing clues to our solar system's origins, and someday could even serve as stepping-stones for space exploration. In this book, Donald Yeomans introduces readers to the science of near-Earth objects—its history, applications, and ongoing quest to find near-Earth objects before they find us. In its course around the sun, the Earth passes through a veritable shooting gallery of millions of nearby comets and asteroids. One such asteroid is thought to have plunged into our planet sixty-five million years ago, triggering a global catastrophe that killed off the dinosaurs. Yeomans provides an up-to-date and accessible guide for understanding the threats posed by near-Earth objects, and also explains how early collisions with them delivered the ingredients that made life on Earth possible. He shows how later impacts spurred evolution, allowing only the most adaptable species to thrive—in fact, we humans may owe our very existence to objects that struck our planet. Yeomans takes readers behind the scenes of today’s efforts to find, track, and study near-Earth objects. He shows how the same comets and asteroids most likely to collide with us could also be mined for precious natural resources like water and oxygen, and used as watering holes and fueling stations for expeditions to Mars and the outermost reaches of our solar system.

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.

For the first time, scientists could have the knowledge to prevent a natural disaster epic in scale—an asteroid hitting the earth and in this exciting, adventuresome book, Carrie Nugent explains how. What are asteroids, and where do they come from? And, most urgently: Are they going to hit the Earth? What would happen if one was on its way? Carrie Nugent is an asteroid hunter—part of a group of scientists working to map our cosmic neighborhood. For the first time ever, we are reaching the point where we may be able to prevent the horrible natural disaster that would result from an asteroid collision. In Asteroid Hunters, Nugent reveals what known impact asteroids have had: the extinction of the dinosaurs, the earth-sized hole Shoemaker Levy 9 left in Jupiter just a few decades ago, how the meteorite that bursted over Chelyabinsk in Russia could have started a war, and unlucky Ms. Anne Hodges—the only person (that we know of) in US history to be the victim of a direct hit. Nugent also introduces the telescope she uses to detect near-Earth asteroids. Ultimately, detection is the key to preventing asteroid impact, and these specialized scientists are working to prevent the unthinkable from happening. If successful, asteroid hunting will lead to the first natural disaster humans have the know-how and the technology to prevent. The successful hunt and mapping of asteroids could mean nothing less than saving life on earth.

Scientists classify comets and asteroids that pass within 28 million miles of Earth's orbit as near-Earth objects (NEOs). Asteroids that collide and break into smaller fragments are the source of most NEOs, and the resulting fragments bombard the Earth at the rate of more than 100 tons a day. Although the vast majority of NEOs that enter Earth's atmosphere disintegrate before reaching the surface, those larger than 100 meters (328 feet) may survive the descent and cause destruction in and around their impact sites. Furthermore, even smaller objects that disintegrate before reaching Earth's surface can cause significant damage. This book examines NASA's NEO Program and assesses the Agency's progress toward meeting statutory and other Program goals. Specifically, it reviews NASA's allocation and use of resources and plans for the future of the Program.

The Earth has limited material and energy resources while these resources in space are virtually unlimited. Further development of humanity will require going beyond our planet and exploring of extraterrestrial resources and sources of unlimited power. Thus far, all missions to asteroids have been motivated by scientific exploration. However, given recent advancements in various space technologies, mining asteroids for resources is becoming ever more feasible. A significant portion of asteroids value is derived from their location; the required resources do not need to be lifted at a great expense from the surface of the Earth. Resources derived from Asteroid not only can be brought back to Earth but could also be used to sustain human exploration of space and permanent settlements in space. This book investigates asteroids' prospective energy and material resources. It is a collection of topics related to asteroid exploration, and utilization. It presents past and future technologies and solutions to old problems that could become reality in our life time. The book therefore is a great source of condensed information for specialists involved in current and impending asteroid-related activities and a good starting point for space researchers, inventors, technologists and potential investors. Written for researchers, engineers, and businessmen interested in asteroids' exploration and exploitation. Keywords: Asteroids, Asteroid exploration, Asteroid exploitation, Energy sources, Space Resources, Material Resources, In-Situ Resource Utilization, Mining

"To commemorate the 50th anniversary of the first successful planetary mission, Mariner 2 sent to Venus in 1962, the NASA History Program Office, the Division of Space History at the National Air and Space Museum, NASA's Science Mission Directorate, and the Jet Propulsion Laboratory organized a symposium. "Solar System Exploration @ 50" was held in Washington, D.C., on 25-26 October 2012. The purpose of this symposium was to consider, over the more than 50-year history of the Space Age, what we have learned about the other bodies of the solar system and the processes by which we have learned it. Symposium organizers asked authors to address broad topics relating to the history of solar system exploration such as various flight projects, the development of space science disciplines, the relationship between robotic exploration and human spaceflight, the development of instruments and methodologies for scientific exploration, as well as the development of theories about planetary science, solar system origins and implications for other worlds. The papers in this volume provide a richly textured picture of important developments - and some colorful characters - in a half century of solar system exploration. A comprehensive history of the first 50 years of solar system exploration would fill many volumes. What readers will find in this volume is a collection of interesting stories about money, politics, human resources, commitment, competition and cooperation, and the "faster, better, cheaper" era of solar system exploration"--