Handbook of Cosmic Hazards and Planetary Defense

Each year humans travel through space on their own very special spacecraft called planet Earth, but that trip around the Sun is actually a very hazardous journey. Without the benefit of a space program, the human species has spent millions of years unaware of the wide range of cosmic dangers that lurk out in space. In some ways humans are playing Russian Roulette with a random set of rock and metal bullets that were first fired at this small six sextillion ton planet millions if not billions of years ago. These bullets are potentially hazardous asteroids, bolides, and meteorites. In addition there are comets that streak down toward the Sun from the Oort Cloud every few years. Perhaps an even greater danger to humans come from the nearby nuclear furnace called the Sun. Solar flares, coronal mass ejections, and continuous radiation from the Sun are warded off by the Van Allen Belts, the Earth’s geomagnetosphere, and the ozone layer that sits atop the stratosphere. During the height of the Sun’s activity that follows an 11-year cycle, the radiation and solar eruptions from the Sun hit very dangerous levels. Current research that examines the Van Allen Belts and the Earth’s magnetic shielding suggests that the protective magnetosphere shielding that protects life could be changing. And then there are other hazards from space. These risks include increasing levels of orbital debris and returning spacecraft that may contain nuclear, radiological, or chemical dangers, or even biological dangers.The Handbook of Cosmic Hazards and Planetary Defense seeks to examine in depth the various dangers that the delicate Earth Habitat could be exposed to from outer space risks and what research needs to be done to understand in greater depth the nature of these dangers. And the editors and the authors of this book are defining “cosmic hazards” in the broadest possible terms. Thus, these hazards from outer space include comets, asteroids, and bolides that might collide with Earth. The risks to humans and modern global infrastructure include solar flares, coronal mass ejections, solar proton events, and other space weather events, as well as changes to the Earth’s protective shielding from cosmic hazards such as a lessened magnetosphere, altered Van Allen Belts, and a depleted ozone layer. This chapter also addresses orbital debris (in terms of its impact on Earth and aircraft as well as such debris possibly endangering vital infrastructure and satellite networks). This chapter even considers such hazards as cosmic radiation, antimatter events, and lethal biological agents that could come to Earth in various forms, including via returning spacecraft or astronauts.The last part of the chapter builds on what is known about the dangers of outer space and presents the various types of activities that humans are beginning to undertake to protect life on Earth. This latter part of the handbook sets forth what types of activities can serve to protect humans and indeed all types of life-forms from mass extinctions. Such massive loss of species that include a third or more of all types of life-forms has been documented to have occurred at least five times during the Earth’s existence. These past mass extinction events have come about, on average, every 300 million years or so, over the last two billion years. These massive losses of life serve as powerful reminder that not only are there powerful hazards that can wipe out life on a massive scale, but that unless protective measures are undertaken, they could happen again with devastating effect. The rise of mass urbanization that may exceed 70 % of all people living in towns of cities by 2100 coupled with the enormous dependence on modern infrastructure such as electric power grids, telecommunications and information systems, and vast utility plants make twenty-first-century vulnerabilities to cosmic risks far greater than any previous time in human history.The objective of this chapter is thus to present in detail what is known about the hazards of outer space and the scientific and technical nature of these threats. Further this handbook seeks to identify what steps can be undertaken to initiate a creditable planetary defense effort. It is such an effort that can unite all the people of planet Earth in a great and common undertaking.

Solar flares are the biggest explosions in the solar system. This tremendous energy release of a single solar flare represents a significant threat to current terrestrial- and space-based systems. This includes any human occupants of space systems who may be exposed to this hazardous energy and radiation environment. Evidence of the deadly nature of these outbursts, and what followed, was clearly demonstrated in 1859 in what has become known as the Carrington Event. Evidence of similar events has been found in the geologic record, most notably Greenland ice cores. From this evidence, it appears events of this magnitude occur approximately once every 500 years. Storms with a fifth of this energy are estimated to occur several times every 100 years. The good news is that these storms typically last but a few hours. More importantly, we have the technology to protect ourselves, both on Earth and in space.

The Sun exhibits different kinds of activity and its appearance is permanently changing, as it is revealed by numerous ground and space observations. The most well-known phenomenon is the 11-year solar activity cycle with an increasing and decreasing number of sunspots on the Sun surface over this period. These sunspots can be tens of thousands of kilometers across. They usually exist as pairs with opposite magnetic polarity alternating every solar cycle. A number of sunspots tend to peak at the solar maximum and are generally manifested closer to the Sun’s equator. Sunspots are darker and cooler than their surroundings because these are regions of the reducing energy convective transport from the hot interiors, which is inhibited by strong magnetic fields. The polarity of the Sun’s magnetic dipole changes every 11 years. This means that the North Magnetic Pole becomes the South one and vice versa. Because solar activity changes from one 11-year cycle to another, the doubled cycles (22 years and longer) are also distinguishable from each other. Irregularity is specifically manifested by a minimum of sunspots and solar activity during several cycles, as significantly occurred in the seventeenth century and is now known as the Maunder Minimum. These cycles strongly impact the Earth’ climate. During the last 11-year cycle, an unusual solar minimum occurred in 2008 and lasted much longer with lower amounts of sunspots than normal. Therefore, solar activity recurrence is not stable. Moreover, theory claims that magnetic instabilities in the Sun core could cause fluctuations with periods that could last tens of thousands of years.Solar flares, coronal mass ejection (CME), and solar proton events (SPEs) are the most characteristic phenomena of these changes in solar activity and their external manifestation. The activity rate as noted above is closely related with the 11-year solar cycle. These solar flare events are often accompanied by the huge ejected amounts of high-energy protons and electrons well exceeding the “normal” energy levels of solar-wind particles. Solar flares, coronal mass ejections (CMEs), solar proton events (SPEs), and normal ejections from the Sun known as “solar wind” have an effect throughout the solar system – especially its inner parts. These phenomena determine the state of geomagnetic fields of planets. Solar plasma and electromagnetic emissions thus have important interactions with the solar system bodies with particular significance for Earth. Solar weather processes impact the Earth’s upper, middle, and lower atmosphere and even can have negative impacts at the surface. Basically, solar activity events determine the space weather which influences planetary environment and, in particular, the life on Earth. This chapter addresses the known science that is associated with solar flares as well as how these solar flares play a key role in triggering other energetic and harmful solar phenomena. Finally it addresses how solar flares, CMEs, and SPEs in particular impact the Earth’s atmosphere and magnetosphere and especially how these phenomena can create significant negative impacts and major infrastructure risks to the world’s current economic and technological systems.

Coronal mass ejections (CMEs) are the most energetic solar phenomena in the inner heliosphere. CMEs are large structures of magnetized plasma that move away from the Sun into the interplanetary (IP) space, driven by the magnetic forces at the Sun. Solar energetic particles (SEPs) and geomagnetic storms are two primary CME consequences that drive space weather on and near Earth. This chapter summarizes current established knowledge of CME properties and their space weather consequences.

The most violent frequently reoccurring events in the solar system are coronal mass ejections. During a high energy cycle of the Sun, or solar max, these can happen as often as six times a day. If the most extreme of these events are focused so they directly impact Earth, the force of impact can be the equivalent of a huge number of nuclear bombs that can generate an electromagnetic pulse (EMP) with devastating effect. Such a pulse could cripple the world’s electrical grids and knock out most satellites in orbit. This chapter describes the so-called CME phenomenon and current understanding of why and how they occur. The final element of the chapter discusses the Earth’s naturally occurring protective systems that minimize the impact of these otherwise deadly occurrences.

The sun is the most important element in the Solar System. Without it life would not exist. When the sun dies in an explosive nova billions of years in the future, this will be the end of existence as now known to humanity. Thus heliophysics, or the understanding of the nuclear fusion processes of the sun and its overall dynamics, has been one of the top priorities for astronomers, astrophysicists, and scientists even before the start of the Space Age. With the ability to put telescopes, gamma and X-ray detectors, spectrometers, coronagraphs, and other sensing instruments into space, there have been a wealth of space projects designed to study the sun and its operation over the past 50 years. There have been missions from NASA, the US Navy and Air Force supported by observatories, research universities, and key research institutes. Further there have been important civilian and military space research missions from France, Germany, Japan, and other countries as well. This chapter seeks to cover in a summary fashion many of the earlier solar and heliophysics research as well as military backed missions. These pioneering efforts have helped to unlock some of the mysteries of the sun’s internal operations and have provided insights that have helped us to design better solar probes for current space experiments and monitoring spacecraft currently studying the sun.This chapter starts with discussing a number of the solar-related experiments carried out by the Orbiting Solar Observatories, the Solwind (P78-1) Project, and Helios-A and Helios-B that represented the very first solar probes. Next the Skylab experiments carried out by onboard astronaut experimenters are described. This is followed by recapping key elements that come from the following space probes: the Solar Maximum Mission, the Upper Atmosphere Research Satellite (UARS), and the Active Cavity Radiometer Irradiance Monitor (ACRIM) Satellite. Data from these sources have produced significant information on total solar irradiance and how the sun’s power output actually varies about 0.1 % over time. This is followed by information on the Coriolis satellite, the Ulysses satellite, the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), Windsat, the Yohkoh satellite (also known as Solar-A) and Hinode (also known as Solar-B), and the Transition Region and Coronal Explorer (TRACE) satellite.

The NASA Wind spacecraft, launched in November 1994, provides comprehensive and continuous in situ solar wind measurements while orbiting the Sun–Earth first Lagrange point upstream of Earth. The spacecraft has a full complement of instruments to measure the local magnetic and electric fields and thermal solar wind and high-energy charged particles at unprecedented high time resolutions. After nearly 20 years of operation, the spacecraft and most instruments are fully operational, and Wind is expected to remain in service for many years to come. While Wind provides real-time solar wind measurements for only about 2 h every day – thus it is not considered an operational space weather monitor – the high-quality and continuous Wind observations have been critical in developing current space weather forecasting techniques. In particular, Wind observations led to better understanding of the propagation and evolution of coronal mass ejections quantifying their distortions and deflections. Wind radio science results significantly added to the understanding of the inner heliospheric propagation of interplanetary shocks and high time resolution field and particle measurements revealed the mechanisms of how these shocks and magnetic reconnection can accelerate charged particles to very high and harmful energies. Wind is expected to continue its contribution to the development of future space weather forecasting capabilities as its measurements near two complete 11-year solar cycles allowing the identification of long-term trends.

SOHO is the most comprehensive space mission ever devoted to the study of the Sun and its nearby cosmic environment known as the heliosphere. It was launched in December 1995 and is currently funded at least through the end of 2016. SOHO’s 12 instruments observe and measure structures and processes occurring inside as well as outside the Sun and which reach well beyond Earth’s orbit into the heliosphere. While designed to study the “quiet” Sun, the new capabilities and combination of several SOHO instruments have revolutionized space weather research. This article gives a brief mission overview, summarizes selected highlight results, and describes SOHO’s contributions to space weather research. These include cotemporaneous EUV imaging of activity in the Sun’s corona and white-light imaging of coronal mass ejections in the extended corona, magnetometry in the Sun’s atmosphere, imaging of far-side activity, measurements to predict solar proton storms, and monitoring solar wind plasma at the L1 Lagrangian point, 1.5 million kilometers upstream of Earth.

NASA’s Solar Dynamics Observatory (SDO) stands sentinel for the cosmic hazards created by solar activity. The instruments on SDO provide immediate knowledge and understanding of solar eruptive events such as flares and coronal mass ejections. In the longer term SDO provides scientific understanding to better predict the trends of solar activity over the next few months to years. SDO comprehensively observes the magnetic field of the Sun. It measures the surface magnetic field and observes the response of the solar atmosphere to changes in the magnetic field. SDO also gathers helioseismic observations that are analyzed to look inside the Sun and deduce the workings of the solar convection zone – the roiling motions inside the Sun that create the magnetic field. SDO, the data it produces, and some of the science results that help with planetary defense will be described.

NASA’s twin STEREO probes, launched in 2006, have advanced the art and science of space weather forecasting more than any other spacecraft or solar observatory. By surrounding the Sun, they provide previously impossible early warnings of threats approaching Earth as they develop on the solar far side. They have also revealed the 3D shape and inner structure of CMEs – massive solar storms that can trigger geomagnetic storms when they collide with Earth. This improves the ability of forecasters to anticipate the timing and severity of such events. Moreover, the unique capability of STEREO to track CMEs in three dimensions allows forecasters to make predictions for other planets, giving rise to the possibility of interplanetary space weather forecasting too. STEREO is one of those rare missions for which “planetary hazards” refers to more than one world. The STEREO probes also hold promise for the study of comets and potentially hazardous asteroids.

In this chapter the reviews of radiation electron anomalies and seismic activities, remediation of natural and artificial radiation belts, and feasibility of an electric generator converting kinetic energy of particles of the radiation belts into electric power are provided.

There is a wide range of radiation and particles that stream to Earth from the Sun and the universe at large. This hostile array of high-energy ionic particles and electromagnetic radiation impacts Earth on a constant basis. The exact nature of this bombardment can be confusing to understand. This is because the blanket term of “cosmic radiation” includes not only intense and high-energy electromagnetic radiation in the form of gamma and X-rays but also ionic particles and nuclei accelerated to speeds even nearing the speed of light. This radiation when it hits Earth’s atmosphere generates a number of different particles including positrons (or antimatter) as well as high-energy photons. This chapter seeks to provide some basic information and definitions related to solar and cosmic “radiation” and to explain that both high-energy X-rays and gamma (γ) rays as well as ionic particles are included in the general and generic phrase “cosmic radiation.”

An overview is provided of the radiation health challenges associated with extended human missions into deep space with the understanding that this is a complex endeavor presently under active research and development. Hence, this chapter necessarily reflects present limitations and the need for research to make such exploration missions possible. The space radiation environment is introduced followed by a brief discussion of the radiobiology. The remainder of the chapter is focused on human health concerns from radiation exposure during extended deep space missions. Although the challenges are many, the greatest radiation-related concern from a mission perspective would be an exceptionally large solar-energetic-particle (SEP) event. Such an event, should it occur during extravehicular activity (EVA), or while in a spaceship insufficiently shielded, could potentially result in acute radiation sickness. Fortunately, radiation from SEP events can be shielded and therefore should be manageable through a combination of shielding design and early warning systems. In contrast, the ever-present chronic exposure to galactic cosmic radiation (GCR) is difficult to shield and will likely have to be accepted at some level. Although GCR produces a much lower dose rate than a large SEP event, there are significant uncertainties concerning the effects from the high-charge, high-energy (HZE) component of GCR. It has been estimated that GCR radiation may induce a significant lifetime cancer risk. It is less clear whether health effects such as cardiovascular or central nervous system problems will result from protracted GCR exposure. It is hoped that these and many other uncertainties will be reduced through research and development prior to sending humans to Mars.

The space environment in the vicinity of spacecraft orbits is replete with a variety of natural and manmade threats from impact of high-speed objects. Setting aside the massive objects such as meteorites and orbital debris, it is apparent that the seeming serenity left behind is still punctuated with a boiling assortment of invisible hazards in the form of high-energy charged particles, plasmas, and electromagnetic radiation. Effects from such threats can reach down into the atmosphere to high-altitude aircraft, ground technologies, and into the DNA of living systems. Here, focus is made on the spacecraft material itself including effects on the associated subsystems. The fundamental nature, source, and temporal-spatial variation of the radiation environment affecting present and future spacecraft traffic is the subject of much in-depth research but is described broadly in order to conceptualize the hazard. Spacecraft material damage is described as either localized material damage at the atomic level or damage to the overall satellite from charge accumulation and surface erosion. The localized hazards apply mostly to susceptible spacecraft sub-components at the particle level, particularly in solid-state microelectronics composed of miniaturized circuitry. The macro hazards have a broad effect over entire surfaces or can be an accumulation of localized damage over the mission of the spacecraft. Surface erosion and contamination is of less immediate consequence but can be eventually disruptive to mission objectives. The environmental sources and distribution of ionizing radiation are addressed including how they couple to the magnetic fields influencing their trajectories and flux concentrations. Given this background, the topic is concluded by addressing the established methods for radiation hazard avoidance and shielding.

The Cluster mission has been operated successfully for 14 years. As the first science mission comprising four identical spacecraft, Cluster has faced many challenges during its lifetime. Initially, during the selection process where strong competition with SOHO was almost fatal to one of them, finally both missions were merged into the Solar Terrestrial Science Programme with strong support from NASA. The next challenge came during the manufacturing process where the task to produce four spacecraft in the time usually allocated to one demanded considerable flexibility in the production process. The first launch of Ariane V was not successful, and the rocket exploded 40s after takeoff. The great challenge for the Cluster scientists was to convince ESA, the National Agencies, and the science community that Cluster should be rebuilt identical to the original one. The fast rebuilding phase, in 3 years, and the 2nd launch on two Soyuz rockets, paved the way to numerous ESA launches afterward. Finally in the operational phase, the challenge was to operate four spacecraft with the funding for one, to solve serious anomalies, and to extend the spacecraft lifetime, now seven times its initial duration with some vital elements such as batteries not working at all. After the technical challenges, the key scientific achievements will be presented. The main goal of the Cluster mission is to study in three dimensions small-scale plasma structures in key plasma regions of the Earth’s geospace environment: solar wind and bow shock, magnetopause, polar cusps, magnetotail, plasmasphere, and auroral zone. Science highlights are presented such as ripples on the bow shock, 3D current measurements and Kelvin-Helmholtz waves at the magnetopause, bifurcated current sheet in the magnetotail, and the first measurement of the electron pressure tensor near a site of magnetic reconnection. In addition, Cluster results on understanding the impact of coronal mass ejections (CME) on the Earth’s environment will be shown. Finally, how the mission solved the challenge of distributing huge quantity of data through the Cluster Science Data System (CSDS) and the Cluster Archive will be presented. Those systems were implemented to provide, for the first time for a plasma physics mission, a permanent and public archive of all the high-resolution data from all instruments.

Since the launch of Explorer 1 in 1958, physicists have studied magnetospheric plasma regions by only being immersed in them. This was done by creating large databases of in situ observations taken at vastly different times and under different magnetospheric conditions. This approach allowed models of these regions to be created that offered some insight as to global processes. In most cases these models were also pushed beyond their limits in an effort to try and describe the structure and dynamics of our geospace environment under all solar wind conditions. That all changed with the launch of the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft on March 25, 2000. The overall objective of the IMAGE mission was to answer the key question: How does the magnetosphere respond globally to the changing conditions in the solar wind?IMAGE was designed to observe vast plasma regions of the inner magnetosphere before, during, and after geomagnetic storms using neutral atom imaging (NAI) at various energies, far ultraviolet imaging (FUV), extreme ultraviolet imaging (EUV), and radio plasma imaging (RPI). These revolutionary instruments provided detailed images of aurora, the ring current, and the plasmasphere at minutes to tens of minute resolution that have greatly changed our view of magnetospheric dynamics. It is not possible to discuss all the results that IMAGE observations have contributed to the understanding of space weather, but we will provide a brief overview concentrating on the ring current and plasmasphere.

The ISEE-1&2 Explorers were a joint NASA-ESA program with instruments on both spacecraft from the USA and Europe with ISEE-1 built in the USA and ISEE-2 in Europe, launched on a single rocket into the same orbit. The interspacecraft distance was variable, allowing the velocities of the boundaries traversed by the spacecraft to be measured and hence their thickness to be determined and compared quantitatively with theory. The missions’ major discoveries included determining that magnetic reconnection controlled magnetospheric dynamics, what factors controlled the rate of reconnection, and which plasma physical processes provided the dissipation for collisionless shocks. Together with ISEE-3 stationed in orbit around the L-1 Lagrangian point, this was the first space weather mission.

GEOTAIL spacecraft launched on 24 July 1992 has explored the Earth’s magnetotail across the range of 10–210 R_E from the Earth. GEOTAIL not only clarified the basic structure of the magnetotail both in quiet and active times, but it also revealed the kinetics of the plasma that underlies macroscopic dynamics. In the magnetotail magnetic reconnection is the key process which governs energy dissipation and acceleration of ions and electrons. GEOTAIL has addressed the relation between the reconnection and auroral phenomena and clarified the kinetics of the energy conversion process in the reconnection region that operates on the scale of the ion inertia length. Understandings have also been advanced on the entry of the solar wind plasma into the magnetotail due to turbulence generated on the magnetopause and the excitation of plasma waves on account of prevalent nonequilibrium velocity distributions of plasma particles. The processes addressed by in-situ observations by GEOTAIL in space should be common to collisionless plasmas that prevail in astrophysical objects.

As society’s reliance on technological systems grows, so does our vulnerability to space weather. It is becoming increasingly important to be able to study and observe space weather and to predict events and conditions on the Sun and in near-Earth space. Timely delivery of space weather data and information enables us the ability to develop preventative or mitigating plans to reduce potentially harmful societal and economic impacts.The Space Weather Prediction Center (SWPC) is NOAA’s official source of space weather alerts, watches, and warnings. It is the primary warning center for the International Space Environment Services (ISES). The SWPC has a key role in providing real-time monitoring and forecasting of solar and geophysical events, exploring and evaluating new models and products, and overseeing their transition into operations. It maintains a website with a dashboard display for summarizing the vast amount of space weather data collected from numerous ground- and space-based systems.The purpose of this chapter is to review how digital dashboards have been effectively used by NASA and NOAA to visualize, communicate, and manage solar weather data for at-a-glance monitoring. In terms of information management, a digital dashboard is considered to be an easy to read, often single page, real-time user interface, enabling graphical presentation of data in a visual manner at a very high level. Such dashboards are becoming an integration of information management and decision support systems. This has proven to be a useful way of consolidating and displaying space weather products, as well as the preferred mode for the SWPC to relay summaries, warnings, and alerts to its user community.Dashboards are able to centralize information and offer users the ability to create customized views on a web-based interface. NOAA products can be readily displayed providing near- and long-term forecasts and trends related to geomagnetic storms, solar radiation storms, radio blackouts, and other solar events. For example, the SWPC dashboard provides near-real-time measurements from about 40 types of space weather operational products from GOES satellites, ground-based magnetometer measurements, and spacecraft, such as NASA’s ACE and NASA/ESA’s SOHO.The Community Coordinated Modeling Center (CCMC) is a multiagency partnership that provides the international research community with access to modern space science simulations. It is also responsible for developing advanced, online, visualization and analysis tools to facilitate a link between the research community and operational users and forecasters. The CCMC has developed dashboard systems, including the Space Weather Scoreboard, the Integrated Space Weather Analysis (iSWA), and the Database Of Notifications, Knowledge, and Information (DONKI).This chapter discusses some of the latest developments in dashboard displays for space weather monitoring and data dissemination. It first reviews the socioeconomic impact of space weather and the need for reliable communication and monitoring of solar observation data for the general public. Digital dashboards are described in general, as well as specific examples of how they are applied by NASA and NOAA for space weather data display. Examples of digital dashboards are reviewed including the iSWA and DONKI systems developed by the CCMC. Finally, the benefits and challenges of developing, implementing, and using digital dashboards for solar weather monitoring are discussed.In general, dashboard displays offer a robust and integrated system for providing information about past, present, and future space weather conditions. Providing a web-based interface, information enables public access to real-time imagery and information via the Internet and mobile devices. There are also a range of web tools available, enabling the user to customize the interface to suit unique data and forecasting requirements. Such technological developments encourage the continual availability and free exchange of space weather data and products worldwide for real-time forecasting and monitoring of space weather. Dashboard display and visualization tools support a multitude of planners and decision-makers for taking proactive measures to mitigate the impacts of potentially damaging space weather events.

Ultraviolet radiation is a component of cosmic radiation that represents a health hazard to humans and indeed to many types of flora and fauna. Ultraviolet and X-ray radiation has the ability to penetrate the Earth’s atmosphere. Ultraviolet (UV) and even more energetic X-ray radiation can have harmful effects on human health, including cellular damage in living tissues that can cause genetic mutations and skin cancer. Stratospheric ozone generally prevents damaging ultraviolet radiation from reaching the Earth’s surface. This protective function of ozone plays an important role in regulating the temperature structure of the atmosphere and climate system. Monitoring stratospheric ozone is an important endeavor for many reasons, including assessing the recovery of ozone levels following the implementation of the Montreal Protocol and subsequent amendments. Long-term and global mapping of total column ozone and the ozone vertical profile are thus essential functions. These ozone monitoring functions can be provided by satellite-based remote sensing instruments.This chapter examines the Solar Backscatter Ultraviolet (SBUV) instruments on weather satellites operated by the US National Oceanic and Atmospheric Administration (NOAA). SBUV instruments have captured the longest continuous record of ozone measurements since the NimbusNimbus-4 satellite was launched in April 1970. This chapter first details the development of the SBUV instrument and its operational timeline. A technical overview of SBUV instrument mechanics and operation is provided, as well as a review of calibration procedures, retrieval algorithms, and sources of error. Finally, primary applications and benefits of SBUV subsystems for measuring global ozone distribution are presented in some detail. In addition, future challenges and developments for collecting high vertical resolution and temporal ozone data are addressed.The long-term operation of the SBUV family of instruments has supported a successful ozone monitoring program. However, combined instrumentation from next-generation NOAA weather satellites is required in order to continue an unbroken ozone record. Such observations are necessary for supporting trend studies and model testing for forecasting what global ozone levels will be in the future.

In 1994 comet Shoemaker-Levy 9 captured the world’s attention. Discovered quite by accident, this comet was to provide the world the first direct observational evidence of an impact by one body on another body in the solar system. Comet Shoemaker-Levy 9 put on a spectacular display. The comet Shoemaker-Levy 9 fragments collided with Jupiter from July 16 through July 22, 1994. The glorious show put on by comet Shoemaker-Levy 9 in July 1994 should continually remind us that the threat of impact from above is very real. We must be continually vigilant.

As we become more aware of cosmic risks to human existence, there have been more and more efforts to identify the nature of these risks, share information as to the nature and types of these risks on a global scale, and even initiate and execute programs to carry out some form of planetary defense. The most obvious of these threats are potentially hazardous asteroids, comets, and bolides that we know can result in planetary disaster and mass exterminations. Increasing efforts have been undertaken to identify the nature of cosmic risks and to devise programs that can assist with planetary defense. This chapter seeks to identify some of the most important reports and programs that have been prepared to address planetary risks and possible defense and mitigation activities. Some of the activities are well advanced, while others are just beginning.Although the bulk of national, regional, and international efforts related to planetary defense around the world, as addressed in the chapter on “Planetary Defense, Global Cooperation, and World Peace,” is indeed to identify, catalog, respond, and mitigate harmful objects that could crash into Earth, this is starting to change. The world community is clearly alerted to the mounting risks of orbital debris. Further research by a number of space-faring nations is increasingly identifying the serious risks associated with solar and cosmic radiation, coronal mass ejections, and orbital debris and even beginning to address external or alien viruses and cosmic radiation. Therefore, some of the important reports and initiatives with respect to these other threat areas, particularly with regard to the efforts of the World Meteorological Organization, are also noted at the end of this chapter. Nevertheless, the major portions of this chapter are directed to key reports such as those of the Working Group on Near-Earth Objects (WGNEO) of the International Astronomical Union and the annual report by NASA to Congress with regard to the Safeguard program, the work of the Association of Space Explorers, the Panel on Asteroid Threat Mitigation, the Action Team-14, and the work of the UN Committee on the Peaceful Uses of Outer Space.Today most of these reports and efforts are directed at “detection” and achieving a better scientific understanding of the level of cosmic threats as well as a wider sharing of threat information on a global basis. Increasingly, in the last few years, these efforts have also transitioned to the development of preventive programs that actually begin to see viable ways to “implement” global defenses against cosmic threats. Today, the International Astronomical Union, the International Academy of Astronautics, the United Nations (as discussed in the earlier chapter), the Association of Space Explorers, the Action Team-14, as well as NASA, ESA, and other national and regional space agencies support the abovementioned efforts. All of these efforts play a prime role in publishing critical information about cosmic hazards and planetary defense in various locations but with prime focus on the Minor Planet Center in Cambridge, Massachusetts, in the USA. In the future, however, a growing number of institutions will be involved. Organizations playing a key role today range from the Association of Space Explorers, the Planetary Society, the Safeguard Foundation, and the B612 Foundation (which is implementing the new Sentinel infrared telescope). Key roles are also played by academic institutions such as the Minor Planet Center (at the Harvard University and Smithsonian Astrophysical Observatory) as well as observatories around the world. Even commercial space programs are involved since micrometeoroids are a threat to commercial satellite programs. These entities and more will thus play an increasing and positive role in informing the public as well as implementing defensive programs.

This chapter reviews the history of and the results from the Deep Impact mission, its extension as the EPOXI mission, and its further extension as a remote observatory for cometary studies. The mission has had a major impact on the understanding of comets and on their role in solar system formation. It has also provided considerable information needed for planetary defense against Near-Earth Objects (NEOs).

NASA is examining concepts for the Asteroid Redirect Mission, in which the agency would launch a robotic spacecraft to capture and redirect an asteroid into a stable orbit in the Earth-Moon system. This would be followed by an early use of the powerful Space Launch System (SLS) launch vehicle and Orion crew spacecraft to ferry astronauts to retrieve samples and return to Earth. NASA is examining two options for the robotic segment: one to redirect a small asteroid to a lunar distant retrograde orbit (LDRO) and another to extract a cohesive mass from a larger asteroid and return it to this same orbit. A preliminary set of mission objectives includes opportunities for planetary defense deflection demonstrations. This brief chapter describes the mission concepts currently under examination in preformulation, including aspects and potential applications to planetary defense.

The primary objective of the Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) mission is to return pristine samples of carbonaceous material from the surface of a primitive asteroid. The target asteroid, near-Earth object (101955) Bennu, is the most exciting, accessible, and volatile- and organic-rich remnant from the early Solar System. OSIRIS-REx returns a minimum of 60 g of bulk regolith and a separate 26 cm2 of fine-grained surface material from this body. Analyses of these samples provide unprecedented knowledge about presolar history, from the initial stages of planet formation to the origin of life. Prior to sample acquisition, OSIRIS-REx performs comprehensive global mapping of the texture, mineralogy, and chemistry of Bennu, resolving geological features, revealing its geologic and dynamic history, and providing context for the returned samples. The instruments also document the regolith at the sampling site in situ at scales down to the sub-centimeter. In addition, OSIRIS-REx studies the Yarkovsky effect, a non-Keplerian force affecting the orbit of this potentially hazardous asteroid (PHA), and provides the first ground truth for telescopic observations of carbonaceous asteroids.

The nonprofit B612 Foundation is building a space observatory called Sentinel. Its goal is to find a much larger number of smaller-scale asteroids than previous ground-based and space-based surveys because of its improved capabilities. Sentinel will be able to detect potentially harmful asteroids that may impact Earth with sufficiently early warning to permit the deflection of the threat. The Sentinel mission will position a 0.5-m infrared telescope in an orbit around the Sun’s interior to the Earth’s orbit and will scan space in the region near the Earth’s orbit for at least 6.5 years. There are an estimated one million asteroids near the Earth that are larger than 40 m that can destroy a city-sized area if they impact the Earth, and only about 10,000 of these have been found to date since smaller-size asteroids are difficult to observe. Sentinel is designed to find over 100,000 near-Earth asteroids per year. The data collected by Sentinel will allow the orbital path of these detected objects to be determined with sufficient accuracy that it will be possible to map the asteroid’s future path for up to 100 years and assess whether there is a potential for an impact with Earth. Sentinel will be built by Ball Aerospace & Technologies Corp. under an innovative contracting approach that enables substantial cost savings. Sentinel will be privately funded by the B612 Foundation with philanthropic support. Launch is planned for 2018.

NASA’s Wide-field Infrared Survey Explorer (WISE) mission, designed to survey the entire sky at infrared wavelengths, has proven a valuable means of discovering and characterizing the small bodies in our solar system. Modifications to the mission’s science data processing system, collectively known as NEOWISE, have allowed new minor planets to be discovered using this space-based infrared telescope. Using radiometric thermal models, physical properties such as diameter and albedo have been derived for more than 158,000 asteroids, including approximately 700 near-Earth objects and 160 comets. Following the conclusion of its primary mission, the WISE spacecraft was placed into hibernation in February 2011. Now renamed NEOWISE, the spacecraft was brought out of hibernation in 2013 to continue the search for near-Earth objects.

An operational approach to NEO hazard monitoring has been recently developed at European level within the framework of the Space Situational Awareness program (SSA) of the European Space Agency (ESA). Through federating European assets and profiting from the expertise developed in European universities and research centers, it has been possible to start the deployment of the so-called SSA-NEO segment. This initiative aims to provide a significant contribution to the worldwide effort to the discovery and characterization of the Near-Earth Object population, to the computation of the associated hazards, and to the study of the possible mitigation measures. The SSA-NEO segment is intended to work in close cooperation with and to be complemented by the other NEO-related programs of the European Commission. A major achievement in this respect has been the inauguration in May 2013 of the ESA NEO Coordination Centre located at ESRIN (Frascati, Italy), whose services and operations are discussed in detail.

The search for near-Earth objects (NEOs) has been ongoing since the 1970s, but sophisticated search efforts, using modern CCD detectors and computer-aided search efforts, have only been in place since the 1990s. While there are a number of important international contributors to the NEO observational program, including the European Space Agency, NASA provides the primary support for the NEO discovery surveys, the follow-up observational activities, and the NEO physical characterizations observations. NASA also provides support for the Minor Planet Center in Cambridge, MA, and the NEO Program Office at JPL. Currently, the primary ground-based discovery surveys are the Catalina Sky Survey operation near Tucson, Arizona, and the Pan-STARRS group operating on Haleakala on Maui, Hawaii. NEOWISE, an Earth orbital 0.4-m telescope operating in the near infrared, plans to continue NEO discoveries and physical characterizations through 2015.

This chapter addresses the current state of the art in assessing the impact risk from any of the known near-Earth objects over the next century or so. The assessment is made by determining the orbits of potentially hazardous asteroids and comets using the latest sets of tracking measurements and then projecting into the future the possible positions for these objects during close approaches to the Earth. The chapter discusses various computerized risk assessment systems that perform these assessments, along with the scales that are used to assess these risks. The second part of the chapter addresses two important issues in accurately predicting the risk of impact on Earth that have been identified and addressed in recent years. The first of these is the “Yarkovsky effect,” which is the small recoil acceleration acting on an asteroid due to thermal emissions from its surface and which can now be detected, modeled, and accounted for. The second topic to be discussed is the phenomenon of “keyholes,” which are gravitational gateways that can take an asteroid from a close approach on one passage by the Earth to a later impact with our planet. Mapping the keyholes for a potential impactor is an important step in assessing the asteroid’s impact hazard and in planning a possible deflection mission.

Computational models are used to gain insight about the phenomena associated with airbursts caused by the hypervelocity entry, ablation, breakup, and explosion of asteroids and comets in planetary atmospheres. Among the resulting discoveries has been the recognition that airbursts caused by downwardly directed collisions do more damage at the surface than a nuclear explosion of the same yield. They are therefore more dangerous than previously thought. At Sandia National Laboratories, the multidimensional, multi-material shock-physics code, CTH, has been run on high-performance computers using adaptive mesh refinement to resolve phenomena across spatial scales over many orders of magnitude. These simulations have led to the discovery of unexpected phenomena that emerge from the highly directed geometry of these events, such as ballistic plumes that rise to low Earth orbital altitudes before collapsing, ring vortices that descend to the surface and add to the list of damage mechanisms, and the splitting of shallow entry wakes into linear vortices that become visible as twin condensation trails. As scientific understanding has improved, these models are ready to be focused on systematic, high-fidelity, multiscale, multi-physics-based quantitative risk assessments to objectively inform policy decisions associated with planetary defense.

Earth impact by an asteroid or comet represents a rare but potentially catastrophic hazard. Since the majority of Earth’s surface is covered by water, such events are statistically likely to involve oceans or seas. Issues associated with modeling water impacts, from the impact event that generates waves to wave propagation and interaction of the waves with shorelines, are discussed. Simulation results for several scenarios are presented to illustrate the problem and demonstrate the current state-of-the-art methods used for modeling water impacts.

A brief overview is presented of the current and historical processing of observations and orbits by the Minor Planet Center (MPC). The MPC is delegated by the International Astronomical Union with organizing the cataloging of minor bodies in the solar system.

Terrestrial impact by an asteroid or comet represents a rare but potentially catastrophic hazard. This section discusses the technical considerations associated with options to prevent or mitigate such a disaster beyond a civil-defense response. The principal approaches to avert an impact include deflecting the object and/or breaking it up and dispersing the pieces. Decision makers require quantitative information about the options available. Developing useful information requires consideration of the range of threat scenarios, including factors such as object size, composition, and orbit; the time available between detection and impact; and how these factors influence deflection and disruption strategies. Two impulsive deflection approaches, kinetic impactors and nuclear explosives, are discussed in the context of these issues, and the regime of adequacy of these methods for the full range of object sizes and amount of warning time prior to impact is illustrated.

This chapter describes the involvement of the International Astronomical Union on the topic of near-Earth objects, notably through supporting the Minor Planet Center, the IAU Working Group on Near Earth Objects, the organization of NEO-related workshops and symposia, and the management of an IAU web page on Near Earth Asteroids.

NEOShield, a project funded by the European Commission, brings together an international team of 13 partner organizations to address the global issue of near-Earth objects (NEO) impact prevention. The project’s goals are to investigate the feasibility of techniques to prevent a potentially catastrophic impact on Earth by an asteroid or a comet and to develop detailed designs of appropriate missions to test deflection techniques.This chapter highlights some of the NEOShield research results obtained to date. The focus will be on mitigation-related science with a brief discussion of ongoing technology development and test-mission designs. Following a brief introduction to the NEOShield project, the three main NEO deflection techniques investigated are described (the kinetic impactor, blast deflection, and the gravity tractor), and the required or desirable payload instrumentation for each technique is discussed. A necessary prerequisite for the design of a successful deflection mission is accurate knowledge of the relevant physical properties of the threatening object; therefore, some of the key physical properties are addressed. A crucial component of NEOShield is laboratory and numerical modeling work to complement investigations of NEO physical properties based on observational data. Experiments to measure the momentum transfer during hypervelocity impacts into different asteroid analog materials are described, as well as initial results of numerical simulations of kinetic impacts at various velocities into small asteroids with different porosities.

This chapter addresses the several actions that the United Nations has undertaken to address various types of natural and anthropogenic origin cosmic hazards. The primary organizational units that address these issues within the United Nations are the General Assembly; the Committee on the Peaceful Uses of Outer Space (COPUOS) and its Scientific and Technical Subcommittee, Action Team on Near-Earth Objects (Action Team 14); and, in parallel, the Group of Governmental Experts on Transparency and Confidence-Building Measures in Outer Space Activities established by the Secretary-General of the United Nations.In the past decade significant progress has been made by the United Nations in addressing these issues. In 2007 COPUOS agreed on the Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space. In December of that year, the guidelines were endorsed by the General Assembly in its resolution 62/217 (General Assembly, Official Records Sixty-second session, 2007, Supplement No. 20 (A/62/20) Annex “Space Debris Mitigation Guidelines of the Committee on the Peaceful Uses of Outer Space”. http://www.unoosa.org/pdf/gadocs/A_62_20E.pdf. Last accessed Oct 2014). This COPUOS action (i.e., to adopt these voluntary guidelines) is significantly based on the coordinated action that came out of the Inter-Agency Space Debris Coordination Committee (IADC). The IADC is an international forum of governmental bodies for the coordination of activities related to the issues of man-made and natural debris in space. The primary purpose of the IADC is to exchange information on space debris research activities between member space agencies, to facilitate opportunities for cooperation in space debris research, to review the progress of ongoing cooperative activities, and to identify debris mitigation options. The IADC adopted its first set of Space Debris Mitigation Guidelines in 2002 and revised them in 2007 (IADC (2007) IADC space debris mitigation guidelines. http://www.iadc-online.org/index.cgi?item=docs_pub. Last accessed Oct 2014). The IADC mitigation guidelines is a living document and may be updated as new information becomes available regarding space activities and their influence on the space environment.In February of 2010, COPUOS, through its Scientific and Technical Subcommittee, established a working group on the Long-term Sustainability of Outer Space Activities (LTSSA) that is working on another set of draft guidelines to preserve the use of space in the long term. The draft guidelines address four thematic areas: (a) sustainable space utilization supporting sustainable development on Earth; (b) space debris, space operations, and tools to support collaborative space situational awareness; (c) space weather; (d) and regulatory regimes and guidance for actors in the space arena. These activities by COPUOS are addressed in this chapter along with its many significant actions related to near-Earth objects. Recommendations concerning the international response to an asteroid impact threat, now approved by the UN General Assembly as of December 2013, have largely derived from the Third United Nations Conference on the Exploration and Peaceful Uses of Outer Space (UNISPACE III Follow Up Action Teams. http://www.unoosa.org/oosa/unisp-3/followup/teams_contact_list.html#recomm14. Last accessed Oct 2014) held in July 1999 in Vienna, Austria. The Action Team 14 that was formed in 2001 and charged with the follow-up to recommendation 14 from this major conference recommended the new international processes to provide global warning and responsive actions now being implemented. The International Telecommunication Union (ITU)International Telecommunication Union (ITU) also has concerns related to extreme solar weather and orbital debris, but these are not prime functions and ITU representatives to COPUOS provide a coordinative point of contact.This chapter not only addresses the history of United Nations actions in the three major cosmic hazards areas but also reports on continuing actions and likely trends for the future.

The orbital particle environment around the Earth is dominated by man-made space objects, except for a limited particle size regime below 1 mm, where meteoroids provide a significant contribution, or may even prevail in some orbit regions. The mass of man-made objects in Earth orbits is on the order of 7,000 tons, of which more than 99 % is concentrated in trackable, cataloged objects larger than typically 10 cm. The mass of meteoroids within the regime of Earth orbits is only on the order of 2–3 tons at any one instant in time, with most probable sizes around 200 μm. As a consequence their size spectrum and associated mass man-made space objects, in contrast with meteoroids, represent a considerable risk potential for space assets in Earth orbits. To assess related risk levels, a good understanding of the space debris environment is essential, both at catalog sizes and sub-catalog sizes. The derivation process and the key elements of today’s debris environment models will be outlined, and results in terms of spatial densities and impact flux levels will be sketched for those orbit regions that are most relevant for space applications.To cope with the existing space debris environment, spacecraft can actively mitigate the risk of collisions with large-size, trackable space objects through evasive maneuvers. Alternatively, or in addition, the risk of mission-critical impacts by non-trackable objects can be reduced through shielding, in combination with protective arrangements of critical spacecraft subsystems. With a view on the future debris environment, international consensus has been reached on a core set of space debris mitigation measures. These measures, which will be explained in more detail hereafter, are suited to reduce the debris growth rate. However, even if they are rigorously applied, they are found to be inadequate to stabilize the debris environment. Long-term debris environment projections indicate that even a complete halt of launch activities cannot prevent the onset of a collisional runaway situation in some LEO altitude regimes. The only way of controlling this progressive increase of catastrophic collisions is through space debris environment remediation, with active mass removal, focused on retired spacecraft and spent orbital stages.

The threat of a comet or meteor Earth impact exists and is evidenced by the geologic record of impacts on Earth. More recently is the well-publicized Chelyabinsk meteor airburst that occurred in Russia on February 15, 2013. Explosion was estimated to be on the order of 4–500 kt (TNT equivalent). The resulting airburst explosion resulted in numerous injuries and building damage. Chelyabinsk showed us that the threat to Earth is real. It is also natural. The evolution of the solar system began with mass lumping together, and it is still doing so today. Mass accretion. The Earth is still growing. It will continue to do so in the future. However, this natural order can be hazardous depending on the size of the impactor continuing the mass accretion process. This threat to Earth regarding potentially dangerous impactors must be mitigated. There is a growing international effort and concern, heightened by the Chelyabinsk meteor, to find, characterize, and defend against threatening solar system bodies. The good news is these efforts have begun. They must continue.

The topic of cosmic hazards is most closely associated with comets and asteroids that might crash into Earth with devastating effect. The truth is that in the nearer term adverse solar events might threaten Earth with powerful coronal mass ejections that could also result in a number of disaster scenarios. When these catastrophic events are the focus, the more modest issue of orbital debris is clearly seen as far less threatening. But the truth is that orbital debris also constitutes serious hazards to future human progress and safety in many different ways. Orbital debris will have an increasing chance of disabling critical satellite infrastructure – particularly in low Earth orbit – that can jeopardize critical services and in the case of major collision escalate the buildup of orbital debris even further. Orbital debris is nothing like the threat to life on Earth of say a category 10 asteroid on the Torino Scale colliding with Earth (“the Torino Impact Hazard Scale”), yet this hazard represents a serious problem to the long-term sustainability of space operations that will only get worse unless an active program to undertake debris removal is initiated. Most of what is written about space debris focuses on their characterization in terms of size number and orbital mechanics, the space technology needed to remove debris from orbit, or relevant regulatory issues. Technical papers such as the chapter written by Dr. Heiner Klinkrad describe such aspects as the growing extent of the problem and the factors that are contributing to the rate of buildup of debris. Other chapters of a technical nature often address the very important issue of the best approaches that can be used for debris removal and remediation.Regulatory papers, such as the chapter by Dr. Ram Jakhu and Dr. Fabio Tronchetti, on the other hand, address the current “due-diligence procedures” that are aimed at preventing or minimizing the creation of new debris. They also consider the questions of liability and legal responsibility and efforts aimed to create new regulatory processes within the UN system to control debris and/or remove debris from orbit.The focus of this chapter, however, is on examining the merits of establishing national, regional, and in time perhaps universal agreements to establish economic funds or entirely new international cooperative mechanisms to oversee the removal and mitigation process. The purpose of such a new international entity or international fund would be manyfold. Such mechanisms or economic processes would create financial incentives both to prevent new debris from occurring and for the removal of existing debris. It would create a recognized international process for active debris removal that would be consistent with existing UN treaties and to which all countries would be able to respond. Such an active response would be in recognition of the incentives for active debris removal as well as penalties associated with either the creation of new debris or not supporting the removal of debris.The ability to create universally accepted new international mechanisms to undertake such tasks as active debris removal is more difficult than it was several decades ago. This is due to the ever-increasing number of nations who are now within the UN system and that now participate in COPUOS, the lack of a cohesive support for coordinated world initiatives – such as existed immediately after World War 2 – and the divergence of world economic, political, and strategic interests in outer space. This divergence of views is particularly noticeable in the outer space arena since this sector is often associated with military and strategic applications on the part of many spacefaring nations. This divergence of views suggests that any new international arrangements related to the active removal of orbital debris will most likely follow an evolutionary path. In short, any longer-term international consensus to address the orbital debris problem will most likely be developed slowly over time. Since the key UN space treaties were developed in the 1960s and early 1970s, no major new space conventions have been agreed since.This chapter thus discusses possible evolutionary processes – led by economic mechanisms or active mitigation and removal techniques that directly reduce the orbital debris buildup. These processes are most likely to start – at the national and regional level and ultimately transition to the global level as time goes by. This might lead to longer-term efforts to create an international mechanism or organizational mechanism to address not only the space debris problem but perhaps other space operations issues such as commercial space flight safety, space traffic management, space and improvement in the near-Earth space environment, etc. (Jakhu et al. (2011) The need for an integrated regulatory regime for aviation and space: an ICAO for space? Springer Wien, New York).

Potentially hazardous asteroids and comets or, more generally, potentially hazardous objects (PHOs) are defined to be near-Earth asteroids or comets (near-Earth objects [NEOs]) with orbits that come close to Earth. These potentially hazardous objects have the potential to cause significant human suffering unlike anything we have encountered in our history if Earth impact with a PHO did indeed occur. The population of NEOs with a diameter larger than one (1) kilometer is estimated to be 1,000 objects. The estimated population with diameters greater than 40 m is a 1,000 times (one million) greater. Overall, it is estimated that over one million NEOs exist that could cause damage to the Earth from impact. None yet has been found that poses an immediate threat. We must continue to be vigil, and current programs watching the heavens are presented.

Discussion of the potential threats to population from accidents involving satellite payloads utilizing radioisotopes for power generation or heating. Accidents include launch aborts and on-orbit failures that subsequently lead to Earth impact and possible release of radioactive materials. Understanding risks and acceptance prior to launch and contingency operations used to mitigate impact or release.

In the 1980s Donald Kessler of NASA noted the continuing buildup of space debris and projected that if not mitigated, it would severely limit future safe access to space. In particular, he noted that at some stage the accumulation of orbital space debris would begin to create new debris due to collisions and that this cascading process would threaten the long-term sustainability of human activities in space, including key space applications for communications, navigation, remote sensing, and weather monitoring. This concern, which today is quite real, has become known as the Kessler syndromeKessler syndrome. Today there are international guidelines to control the debris population by deorbiting the upper stages of launch vehicles and other preventive measures. These include the 25 year rule for active or passive deorbiting of debris and the degassing of excess fuel that can lead to explosions in space. But these guidelines are insufficient to prevent the buildup of additional debris, particularly in low earth orbit and polar orbits, where the problem is more severe. There is increasing international agreement that a process for active removal of orbital debris elements – once they are clearly defined – will become necessary to address this problem that continues to grow worse over time despite the guidelines to minimize new debris.This orbital debris problem is a difficult one for many reasons. The cost of active debris removal is very high and the appropriate technology that would be ideal for this purpose remains elusive. Nevertheless, many proposals regarding various debris mitigation methodologies are being pursued. The launch of many small satellites with many of them lacking either an active or passive deorbit capability complicates the orbital debris problem even further. In addition to the technical and prohibitive cost associated with active orbital debris mitigation, there are legal issues as well. The current space law regime has no formal definition of space debris in that all elements in space are simply known as “space objects” despite whether they are functional or not. Current legal liability provisions that place all liability with the launching State do not help to facilitate any active removal activity. In short there are no incentives to remove debris from space at this time. This chapter addresses the threats to the long-term sustainability of space posed by the continuing buildup of space debris. In particular, it addresses current efforts and plans around the world to address the space debris problem with active removal and mitigation techniques and possible international legal changes or agreements that might facilitate these actions.

Directed energy in the form of photons plays an increasingly important role in everyday life, in areas ranging from communications to industrial machining. Recent advances in laser photonics now allow very large-scale modular and scalable systems that are suitable for planetary defense. The fundamental requirements of directed energy planetary defense systems are described here, along with the current state of technological readiness. A detailed design is presented for an orbital planetary defense scheme, called DE-STAR for Directed Energy System for Targeting of Asteroids and exploRation. DE-STAR is a modular phased array of kilowatt class laser amplifiers fed by a common seed and powered by photovoltaics. The main objective of DE-STAR is to use focused directed energy to raise the surface spot temperature of an asteroid to ~3,000 K, sufficient to vaporize all known substances. Ejection of evaporated material creates a large reaction force that alters the asteroid’s orbit. Both standoff (DE-STAR) and stand-on (DE-STARLITE) systems are discussed. The baseline standoff system is a DE-STAR 3 or 4 (1–10 km array) depending on the degree of protection desired. A DE-STAR 4 allows initial engagement beyond 1 AU with a spot temperature sufficient to completely evaporate up to 500 m diameter asteroids in 1 year. Small objects can be diverted with a DE-STAR 2 (100 m), while space debris is vaporized with a DE-STAR 1 (10 m). Modular design allows for incremental development, minimizing risk, and allowing for technological co-development. Larger arrays would be developed in stages, leading to an orbiting structure. The smaller stand-on systems (DE-STARLITE) are appropriate for targets with very long lead times to impact so that a dedicated mission can be implemented.

This chapter examines analyses that have been used to assess various types of large-scale economic risks that could apply to the global economy and attempts by such groups as the World Economic Forum to examine what the impact of various types of “Black Swan” catastrophes might be. In particular it indicates why economic systems are generally not well equipped to address major global disasters with worldwide impact that also have a very low probability of occurrence. In light of economic scarcity, conflicting political priorities, and a number of other factors, there is currently little likelihood that a systematic economic response mechanism or a global disaster response fund will be created within the United Nations system or any other global institution. The general conclusion reached is that the evolution of new types of space technologies that might be developed for other purposes such as space debris removal, on-orbit servicing, etc. – may represent the most logical way forward.

This chapter seeks to highlight the various activities that are now ongoing around the world in the planetary defense arena – broadly defined. This chapter also seeks to address key problems and challenges related to future planetary defense and how emerging patterns of collaboration in these areas are evolving in a positive way. In some cases entirely new models of cooperation across a number of diverse technical fields are emerging. Some of these levels of cooperation involve colleges, universities, foundations, and research institutes. Other collaborative links involve corporations, governmental agencies, and even concerned nongovernmental organizations and foundations such as the Association of Space Explorers (ASE), the Safeguard Foundation, and the B612 Foundation. The United Nations has also begun to build effective new collaborative programs. These UN programs are addressed in a separate chapter. In short, much, much more remains to be done, but serious new efforts to collaborate in this daunting field are indeed underway.In addition to reviewing patterns of international cooperation, this chapter also examines some of the national and regional programs of countries that are most active in this area.

The relevance and importance of law for the issue of planetary defense are, and should be seen as, instruments facilitating international cooperation for avoiding legal risks should they arise while carrying out planetary defense operations. Currently, there is a significant absence of a specific legal and regulatory framework governing planetary defense since the international community has for the most part not addressed this matter seriously in the past. There is one important exception in the form of the University of Nebraska study commissioned by the Secure World Foundation (Legal Aspects of NEO Threat Response). In short, there is little legal literature on this issue as the space law community has not yet conducted extensive research in this regard. The situation may be expected to change as the threats from cosmic hazards become more known broadly and processes within the United Nations and the Committee on the Peaceful Uses of Outer Space continue to work in this area particularly through the Working Group on the Long-Term Sustainability of Outer Space Activities (LTSSA).This chapter briefly addresses and highlighted the need for clarifying the main legal issues relevant to planetary defense; i.e., the authority and duty to intervene, the responsibility to undertake planetary defense initiatives, as well as possible liability for damage or injury caused during such operations. It will also identify the challenges to existing international legal rules and suggest possible amendments thereto for undertaking planetary defense. Legal issues related to international response to cosmic disasters will also be briefly addressed.International space law, as provided for in the United Nations (UN) space treaties and in a number of General Assembly resolutions, lacks specific as well as binding provisions dealing with the protection of the Earth from natural cosmic hazards. Nevertheless recent actions by the UN General Assembly have led to new efforts in these areas. This has been seen in the creation in 2010 and 2010 of UN COPUOS Working Group on the Long-Term Sustainability of Outer Space Activities (LTSSA). This has even more recently seen in the actions of the UN General Assembly to activate the International Asteroid Warning Network (IAWN) and the Space Mission Planning Advisory Group (SMPAG) (“International asteroid warning network: first meeting of the steering committee” http://www.minorplanetcenter.net/IAWN/ and “SMPAG: summary of the first meeting” http://blogs.esa.int/rocketscience/2014/02/12/smpag-summary-of-the-first-meeting/comment-page-1/).The prime objective of this analysis is to examine what recent activities have been undertaken by the United Nations General Assembly, the UN Committee on the Peaceful Uses of Outer Space (UN COPUOS), and the UN Committee on Defense Analysis to develop legal or regulatory mechanisms concerning cosmic hazards and planetary defense.The parallel part of this analysis is to consider where principles of public international law can aid in the future development of relevant regulatory or legal concepts to address the major issues presented by cosmic threats.

The current focus related to planetary defense concentrates on detecting cosmic hazards. However, the largest gap in planetary defense is the organization of an appropriate response revolving around operations, command, and control and execution of a planetary defense mission against all threats to the world today. This need for a global response capability applies whether this involves an asteroid, a comet, or a coronal mass ejection or some other threat. There is a need for clear management and control structures that are built on a framework that is based on multilateral enforcement and peacekeeping conventions. Some action has recently been initiated within the United Nations framework via the Committee on the Peaceful Uses of Outer Space at the behest of the General Assembly. But this is really an initial step that must be considered as inadequate in terms of implementing a truly full-scale global response to a major and potentially devastating event with a potentially global impact. Without such framework it is not possible to begin to properly plan for operationalizing planetary defense.

Out of a growing sense of shared vulnerability on a planet whose cosmic environment is recently better known and seemingly less benign than it once appeared, an international response to the cosmic hazards posed by some near-Earth objects and other significant space phenomena has begun to take shape. Although asteroid strikes are far from the only or even most likely threats posed by Earth’s cosmic neighborhood, they have a tangible character that makes them easy to visualize by many people, and they could, in a worst-case scenario, lead to apocalyptic consequences. Thus, among the many very real hazards covered in this handbook, the threat of asteroid impacts is one that has inspired sufficient study and political action to have brought two new institutions into being with the mission of protecting not just a few select countries but the entire planet. Seeking to draw some insights for the problems remaining to be addressed from the progress made in the area of defense against NEOs and to a certain extent other major space hazards, this chapter looks at the political environment and pathways for cooperation that have led to this progress. Lastly, it looks at some of the work remaining to be done to ensure that institutions that have been designed on paper could actually someday meet the challenge of delivering protective measures including something as dramatic as deflecting a massive space rock bound for an unwelcome rendezvous with Earth.

The risks posed by man-made cosmic hazards include pollution in outer space and on Earth primarily caused by artificial space debris and the contamination of the Earth-space environment and celestial bodies created by the release of organic and biological bacteria, radiation released by nuclear reactors used to provide electric power for space objects, and radiation resulting from the use of nuclear weapons or their tests. In general, current international law (including space law) does not provide a satisfactory and binding legal framework to address all the risks posed by these hazards. Nevertheless, the international community has adopted some non-binding regulatory mechanisms to regulate and control these risks. This chapter briefly describes and points out the strengths and weaknesses of these mechanisms. Finally, some recommendations are made with respect to the future actions the international community ought to take in order to avoid or at least minimize the risks posed by man-made cosmic hazards. Clearly there are also a number of legal and regulatory issues related to natural cosmic hazards such as Near-Earth Objects and hazardous solar events, but these issues are addressed in the earlier chapter by Fabio Tronchetti.

“A good rule of thumb is to assume that everything matters.” Richard Thaler

Quantifying risk is a survival mechanism innate to the human race. From the days cavemen built shelters to protect themselves from the elements, the goal has been to mitigate risk. In modern society, insurance, which spreads risk among many to protect the few who have losses, is the backbone of risk mitigation. The hazards addressed are those thought to have the highest probability of causing bodily injury or property damage. Fire, flood, hurricane, and earthquake are common perils covered by insurance.

Cosmic hazards including meteors, coronal mass ejections, solar flares, and orbital debris-related accidents are rare events. Individuals, corporations, governments, and insurance companies do not believe the risk is relevant to them so they do not address it. Even the well-publicized recent meteor event over Chelyabinsk, Russia, causing $30 million in damages and wounding over 1,600 people certainly will not change this (Borenstein S, Russian meteor in chelyabinsk may mean space rocks pose bigger risk than we thought. Huff Post, Science.

http://www.huffingtonpost.com/2013/11/06/russia-meteor-chelyabinsk-space-rocks-risk-studies_n_4227270.html

. Accessed Sept 2014, 2013). While cosmic hazards are off the radar, it does not mean that insurance is not available to cover the damage caused by them. The effects of cosmic hazards are similar to natural catastrophes and covered by insurance in the same way. Insurance policies are written covering all risks of loss with no specific exclusions for cosmic hazards. So, by default insurance companies are covering cosmic hazards. However, if the frequency or severity of hazards does reach consciousness, then insurers will limit coverage, charge a premium for it, or exclude it all together.