Orbital Debris


Book Description

Since the beginning of space flight, the collision hazard in Earth orbit has increased as the number of artificial objects orbiting the Earth has grown. Spacecraft performing communications, navigation, scientific, and other missions now share Earth orbit with spent rocket bodies, nonfunctional spacecraft, fragments from spacecraft breakups, and other debris created as a byproduct of space operations. Orbital Debris examines the methods we can use to characterize orbital debris, estimates the magnitude of the debris population, and assesses the hazard that this population poses to spacecraft. Potential methods to protect spacecraft are explored. The report also takes a close look at the projected future growth in the debris population and evaluates approaches to reducing that growth. Orbital Debris offers clear recommendations for targeted research on the debris population, for methods to improve the protection of spacecraft, on methods to reduce the creation of debris in the future, and much more.







Achieving Science with CubeSats


Book Description

Space-based observations have transformed our understanding of Earth, its environment, the solar system and the universe at large. During past decades, driven by increasingly advanced science questions, space observatories have become more sophisticated and more complex, with costs often growing to billions of dollars. Although these kinds of ever-more-sophisticated missions will continue into the future, small satellites, ranging in mass between 500 kg to 0.1 kg, are gaining momentum as an additional means to address targeted science questions in a rapid, and possibly more affordable, manner. Within the category of small satellites, CubeSats have emerged as a space-platform defined in terms of (10 cm x 10 cm x 10 cm)- sized cubic units of approximately 1.3 kg each called "U's." Historically, CubeSats were developed as training projects to expose students to the challenges of real-world engineering practices and system design. Yet, their use has rapidly spread within academia, industry, and government agencies both nationally and internationally. In particular, CubeSats have caught the attention of parts of the U.S. space science community, which sees this platform, despite its inherent constraints, as a way to affordably access space and perform unique measurements of scientific value. The first science results from such CubeSats have only recently become available; however, questions remain regarding the scientific potential and technological promise of CubeSats in the future. Achieving Science with CubeSats reviews the current state of the scientific potential and technological promise of CubeSats. This report focuses on the platform's promise to obtain high- priority science data, as defined in recent decadal surveys in astronomy and astrophysics, Earth science and applications from space, planetary science, and solar and space physics (heliophysics); the science priorities identified in the 2014 NASA Science Plan; and the potential for CubeSats to advance biology and microgravity research. It provides a list of sample science goals for CubeSats, many of which address targeted science, often in coordination with other spacecraft, or use "sacrificial," or high-risk, orbits that lead to the demise of the satellite after critical data have been collected. Other goals relate to the use of CubeSats as constellations or swarms deploying tens to hundreds of CubeSats that function as one distributed array of measurements.







Safety Design for Space Systems


Book Description

Progress in space safety lies in the acceptance of safety design and engineering as an integral part of the design and implementation process for new space systems. Safety must be seen as the principle design driver of utmost importance from the outset of the design process, which is only achieved through a culture change that moves all stakeholders toward front-end loaded safety concepts. This approach entails a common understanding and mastering of basic principles of safety design for space systems at all levels of the program organisation. Fully supported by the International Association for the Advancement of Space Safety (IAASS), written by the leading figures in the industry, with frontline experience from projects ranging from the Apollo missions, Skylab, the Space Shuttle and the International Space Station, this book provides a comprehensive reference for aerospace engineers in industry. It addresses each of the key elements that impact on space systems safety, including: the space environment (natural and induced); human physiology in space; human rating factors; emergency capabilities; launch propellants and oxidizer systems; life support systems; battery and fuel cell safety; nuclear power generators (NPG) safety; habitat activities; fire protection; safety-critical software development; collision avoidance systems design; operations and on-orbit maintenance. - The only comprehensive space systems safety reference, its must-have status within space agencies and suppliers, technical and aerospace libraries is practically guaranteed - Written by the leading figures in the industry from NASA, ESA, JAXA, (et cetera), with frontline experience from projects ranging from the Apollo missions, Skylab, the Space Shuttle, small and large satellite systems, and the International Space Station - Superb quality information for engineers, programme managers, suppliers and aerospace technologists; fully supported by the IAASS (International Association for the Advancement of Space Safety)




Military space operations common problems and their effects on satellite and related acquisitions.


Book Description

In fiscal year 2003, the Department of Defense expects to spend more than $18 billion to develop, acquire, and operate satellites and other space-related systems. Satellite systems collect information on the capabilities and intentions of potential adversaries. They enable military forces to be warned of a missile attack and to communicate and navigate while avoiding hostile action. And they provide information that allows forces to precisely attack targets in ways that minimize collateral damage and loss of life. DOD's satellites also enable global communications, television broadcasts, weather forecasting; navigation of ships, planes, trucks, and cars; and synchronization of computers, communications, and electric power grids. Congress requested that we review reports we issued on satellite and other space-related programs over the past two decades and identify common problems affecting these programs. The majority of satellite programs cost more than expected and took longer to develop and launch than planned. In reviewing our past reports, we found that these results were commonly tied to the following problems. Requirements for what the satellite needed to do and how well it must perform were not adequately defined at the beginning of a program or were changed significantly once the program had already begun. Investment practices were weak. For example, potentially more cost-effective approaches were not examined and cost estimates were optimistic. Acquisition strategies were poorly executed. For example, competition was reduced for the sake of schedule or DOD did not adequately oversee contractors. Technologies were not mature enough to be included in product development. Several factors contributed to these problems. First, DOD often took a schedule-driven instead of a knowledge-driven approach to the acquisition process. As a result, activities essential to containing costs, maximizing competition among contractors and testing technologies were compressed or not done. Second, there is a diverse array of organizations with competing interests involved in overall satellite development--from the individual military services, to testing organizations, contractors, civilian agencies, and in some cases international partners. This created challenges in making tough tradeoff decisions, particularly since, for many years, there was no high-level official within the Office of the Secretary of Defense dedicated to developing and enforcing an overall investment strategy for space. Third, space acquisition programs have historically attempted to satisfy all requirements in a single step, regardless of the design challenge or the maturity of technologies to achieve the full capability. This approach made it difficult to match requirements to available resources (in terms of time, money, and technology). Other factors also created challenges for the satellite acquisition programs we reviewed. These include a shrinking industrial base, a declining space workforce, difficulties associated with testing satellites in a realistic environment, as well as challenges associated with launching satellites.




Orbital Debris: A Chronology


Book Description

The 37-year (1961-1998) history of orbital debris concerns. Tracks orbital debris hazard creation, research, observation, experimentation, management, mitigation, protection, and policy. Includes debris-producing, events; U.N. orbital debris treaties, Space Shuttle and space station orbital debris issues; ASAT tests; milestones in theory and modeling; uncontrolled reentries; detection system development; shielding development; geosynchronous debris issues, including reboost policies: returned surfaces studies, seminar papers reports, conferences, and studies; the increasing effect of space activities on astronomy; and growing international awareness of the near-Earth environment.




Continuing Kepler's Quest


Book Description

In February 2009, the commercial communications satellite Iridium 33 collided with the Russian military communications satellite Cosmos 2251. The collision, which was not the first recorded between two satellites in orbit-but the most recent and alarming-produced thousands of pieces of debris, only a small percentage of which could be tracked by sensors located around the world. In early 2007, China tested a kinetic anti-satellite weapon against one of its own satellites, which also generated substantial amounts of space debris. These collisions highlighted the importance of maintaining accurate knowledge, and the associated uncertainty, of the orbit of each object in space. These data are needed to predict close approaches of space objects and to compute the probability of collision so that owners/operators can decide whether or not to make a collision avoidance maneuver by a spacecraft with such capability. The space object catalog currently contains more than 20,000 objects, and when the planned space fence radar becomes operational this number is expected to exceed 100,000. A key task is to determine if objects might come closer to each other, an event known as "conjunction," and the probability that they might collide. The U.S. Air Force is the primary U.S. government organization tasked with maintaining the space object catalog and data on all space objects. This is a complicated task, involving collecting data from a multitude of different sensors-many of which were not specifically designed to track orbiting objects-and fusing the tracking data along with other data, such as data from atmospheric models, to provide predictions of where objects will be in the future. The Committee for the Assessment of the U.S. Air Force's Astrodynamic Standards collected data and heard from numerous people involved in developing and maintaining the current astrodynamics standards for the Air Force Space Command (AFSPC), as well as representatives of the user community, such as NASA and commercial satellite owners and operators. Preventing collisions of space objects, regardless of their ownership, is in the national security interested of the United States. Continuing Kepler's Quest makes recommendations to the AFSPC in order for it to create and expand research programs, design and develop hardware and software, as well as determine which organizations to work with to achieve its goals.







Defense Against the Dark Arts in Space


Book Description

The proliferation of counterspace weapons across the globe often calls into question what can be done to best protect satellites from attack. This analysis from the CSIS Aerospace Security Project addresses different methods and technologies that can be used by the United States government, and others, to deter adversaries from attack. A wide range of active and passive defenses are available to protect space systems and the ground infrastructure they depend upon from different types of threats. This report captures a range of active and passive defenses that are theoretically possible and discusses the advantages and limitations of each. A group of technical space and national security experts supported the analysis by working through several plausible scenarios that explore a range of defenses that may be needed, concepts for employing different types of defenses, and how defensive actions in space may be perceived by others. These scenarios and the findings that resulted from subsequent conversations with experts are reported in the penultimate chapter of the report. Finally, the CSIS Aerospace Security Project team offers conclusions drawn from the analysis, actionable recommendations for policymakers, and additional research topics to be explored in future work.