Impact Risk Analysis Research Articles

A study of debris impact collision probabilities to space tethers

The Tether Risk Assessment Program is a new model currently under development at the University of Southampton. It is designed to study the short-term interaction between space tethers and a debris cloud produced by an on-orbit fragmentation event. An impact risk analysis is performed over a 15-days period after a breakup event has occurred using two examples. The first example looks at a single stranded tether similar to that of the Tether Physics and Survivability Experiment. The second example is similar to that of the first but with a double stranded tether. The risk analysis for the chosen examples is presented, along with the current status of the program.

Self-induced collision hazard in high and moderate inclination satellite constellations

The assessment of the hazard posed by space debris to constellations of satellites in low Earth orbit is of growing importance, with the proliferation of proposed and implemented constellation systems with a variety of mission objectives. This applies to current constellation-based commercial communication systems, in particular, since these are typically deployed at altitudes where there is a peak in the space debris environment. An impact risk analysis is performed over a period of up to 1 month after a breakup event using two examples of constellation configurations. The first is similar to the IRIDIUM system, containing around 70 satellites in near-polar orbits at approximately 800 km altitude, and the second is a Globalstar-like configuration with 56 satellites at around 1400 km altitude, distributed in orbit planes inclined at 52°. The analysis is performed using the SDS software, which applies the probabilistic continuum dynamics technique. This has the benefit of being a self-contained and rigorous method. However, it is found to be not well-suited to ‘long-term’ analysis, due to the computational effort required. The risk analysis for the chosen examples is presented, as well as an investigation of the robustness of the method when applied to complex and ‘long-period’ simulations.

A Hybrid Expert System, GIS, and Simulation Modeling for Environmental and Technological Risk Management

RTXPS, the RealTime eXPert System, integrates a forward chaining expert system and a backward chaining system into a DSS framework using simulation models and GIS for environmental and technological risk assessment and management tasks. The system operates in real‐time, and uses time including estimates derived from the forecasting models, in its inference. The architecture features two linked ES strategies, which draw upon an object database of environmental and risk‐relevant objects, including data acquisition from GPS locators and sensors, and a GIS, as well as a set of dynamic simulation models implemented in a distributed client–server environment. Monte Carlo methods are used for the explicit treatment of uncertainty. Application examples describe chemical emergency management cases for fixed installations and transportation accidents, environmental impact assessment and risk analysis applications, and an adaptation for technical training for emergency management.

Alien invasive species in China: their damages and management strategies

The impacts and invasion method of alien invasive species (AIS), and prevention and management of biological invasion are discussed. Biological invasion is becoming one of the most important factors threatening biodiversity and stability of various ecological systems in China. The impacts of these biological invasions are becoming a more serious problems with development and increase of global trade, transportation, international travel and ecological tourism. Harmful AIS often leads to irreversible species extinction, and results in substantial economic losses within managed and natural ecosystems, including agriculture, forestry, fishery and animal production. Newly invading weeds, insect pests and plant diseases frequently result in large-scale outbreaks and persistent use of chemical pesticides. Successful invasion and spread of some major insect pests and weeds in China were caused by man-made factors. These include decision mistakes and unintentional introduction of some plants, such as water hyacinth and alligator weed as pig food, irresponsible introduction actions taken by individual/group without any ecological concerns, and lack of rapid response mechanism for eradicating potentially AIS as soon as they appear. China is an agricultural country. Any biological invasion will be a "big-bomb" for our agriculture and inevitably result in ecological and economic losses in specific ecosystem and specific geographic regions. Prevention of biological invasion is an important aspect for safeguarding the state′s ecological safety. Development and researches should focus on building the state capacity, research capacity, and management capacity for addressing AIS problem. Based on the urgent situation of AIS in China, priority for research and action plans concentrate on: developing methods to identify the origin and pathways of invasive population; understanding the biological and ecological bases of AIS; developing environmentally friendly methods for control of AIS; developing environmental impact assessment and risk analysis methods for AIS; and developing methods for the recovery of habitats after control of AIS.

Assessing the Risk of Orbital Debris Impact

A Space Debris Impact Risk Analysis Tool (SDIRAT) was developed and implemented to assess the orbital debris impact risk on a specified target in Earth orbit, in terms of flux, relative velocity, impact velocity, direction of the incoming particles, debris mass and diameter. Based on a deterministic approach, SDIRAT uses a realistic orbital debris population where each representative particle is identified by its rectangular coordinates (position and velocity) at a reference epoch. Using this information, some geometrical algorithms were developed and implemented to evaluate the contribution of each particle to the incoming flux. The position of the particle with respect to a specified target drives the selection criteria to reject, or select, it as a possible projectile. On the other hand, the relative velocity vector can be used to estimate the impact direction of the incoming flux. SDIRAT was conceived as a general tool for a variety of scenarios, such as low circular and elliptical orbits, up to the geosynchronous ring. This paper presents some examples of possible applications, including the computation of the incoming debris flux on SAX (low Earth orbit), SIRIO (geosynchronous orbit) and the IRIS upper stage (elliptical orbit). Other applications assess the impact risk for the Soviet Radar Ocean Reconnaissance Satellites Cosmos 1900 and Cosmos 1932.

Reviews: The Shaping of America: A Geographical Perspective on 500 Years of History. Volume 1: Atlantic America, 1492–1800, the Annals of the American Academy of Political and Social Science, Volume 485. From Foreign Workers to Settlers? Transnational Migration and the Emergence of New Minorities, Uneven Development and Regionalism: State, Territory and Class in Southern Europe, the Brecon Mandate: Portrait of

Reviews: The Shaping of America: A Geographical Perspective on 500 Years of History. Volume 1: Atlantic America, 1492–1800, the Annals of the American Academy of Political and Social Science, Volume 485. From Foreign Workers to Settlers? Transnational Migration and the Emergence of New Minorities, Uneven Development and Regionalism: State, Territory and Class in Southern Europe, the Brecon Mandate: Portrait of

Environmental Impact Assessment, Technology Assessment, and Risk Analysis. Contributions from the Psychological and Decision Sciences. Proceedings of a NATO Advanced Study Institute Held at Less Arcs Conference Center and Resort Complex (Bourgh-St. Maurice, France), August 21-31, 1983. Vincent T. Covello , Jeryl L. Mumpower , Pieter J. M. Stallen, V. R. R. Uppuluri

<i>Environmental Impact Assessment, Technology Assessment, and Risk Analysis. Contributions from the Psychological and Decision Sciences. Proceedings of a NATO Advanced Study Institute Held at Less Arcs Conference Center and Resort Complex (Bourgh-St. Maurice, France), August 21-31, 1983</i>. Vincent T. Covello , Jeryl L. Mumpower , Pieter J. M. Stallen, V. R. R. Uppuluri

Book Reviews

Book Reviewed in this article:THE LANGUAGE OF RISK D. NelkinRISK AND FREEDOM: THE RECORD OF ROAD SAFETY REGULATION J. G. U. AdamsRISK ANALYSIS AND THE SCIENTIFIC METHOD K. S. Shrader‐FrechetteENVIRONMENTAL IMPACT ASSESSMENT, TECHNOLOGY ASSESSMENT, AND RISK ANALYSIS V. T. Covello et al., (eds.)