Detection of the Earth with the SETI microwave observing system assumed to be operating out in the galaxy

This paper estimates the maximum range at which radar signals from the Earth could be detected by a search system similar to the NASA Search for Extraterrestrial Intelligence Microwave Observing Project (SETI MOP) assumed to be operating out in the galaxy. Figures are calculated for the Targeted Search, and for the Sky Survey parts of the MOP, both operating, as currently planned, in the second half of the decade of the 1990s. Only the most powerful terrestrial transmitters are considered, namely, the planetary radar at Arecibo in Puerto Rico, and the ballistic missile early warning systems (BMEWS). In each case the probabilities of detection over the life of the MOP are also calculated. The calculation assumes that we are only in the eavesdropping mode. Transmissions intended to be detected by SETI systems are likely to be much stronger and would of course be found with higher probability to a greater range. Also, it is assumed that the transmitting civilization is at the same level of technological evolution as ours on Earth. This is very improbable. If we were to detect another technological civilization, it would, on statistical grounds, be much older than we are and might well have much more powerful transmitters. Both factors would make detection by the NASA MOP a much more likely outcome.     

The global positioning system: policy issues for an information technology

This article, based on the executive summary of a RAND Corporation study, analyses the policy issues facing the USA in the use of its Global Positioning System (GPS), in terms of both national security and commercial applications. Foreign policy issues, including how to react to the emergence of non-US (Russian, European and Inmarsat-sponsored) alternatives to the GPS are also examined. The article concludes with a series of recommendations for policy makers. Reprinted by permission.     

Dreams and realities: the challenges facing development of space tourism

The era of public space travel is approaching faster than most people think, driven by the human desire for adventure, travel and fun, and by the economic motivation for creating a space industry. Before this will happen, advances in engineering, law and policy, and medicine must be made, as well as considering the issues involved in business and management. Public awareness of the possibility must be increased and world-wide excitement about space generated in order to make space tourism a reality. This is a slightly edited version of the executive summary of the design project produced by ISU students at their 2000 Summer Session Programme in Valparaiso, Chile.     

Beyond global: the international imperative of space

Despite provisions declarations that outer space shall be free for exploration and use by all states, it is a finite resource. This article argues for the need to ensure rational use of this resource via a major restructuring of space law. Focusing on telecommunications it proposes a change in the assignment of radio-spectrum and suggests that space must be treated as a means of advancing genuine globalisation.     

Achieving GPS–Galileo interoperability: the challenges ahead

The enormous benefits of a worldwide accurate location system can only be achieved if GPS and Galileo can be made truly interoperable. The technical issues involved are relatively easy to deal with but the political and legal problems require far greater attention, with military issues and enactment of legislation the chief difficulties. These are discussed using examples, notably from road traffic law. Given that the US DoD is unlikely to cede control of GPS to the civil sector and design a new, separate system, the best solution might be to set aside part of GPS for purely civil purposes.     

Development of a global EDOS: political support and constraints

The development of a global environmental and disaster satellite observation system (EDOS) has recently received attention, particularly as a potential cooperative project with the USA and Japan as the initiators. Such a system, proponents contend, would provide valuable and potentially lifesaving information to developed and particularly developing countries which might not otherwise have such information available, as well as provide a vehicle to strengthen ties between the USA and Japan at a time when strife over trade issues is too often emphasized. The initiation of such a project, however, has not been without difficulty. Beyond the technical issues, there has been hesitation and scepticism on the part of some national space players concerning the project, often motivated by parochial political concerns rather than conceptual or technical issues. The focus of this article is an examination of those political factors which have acted as impetus and barriers for the initiative, using interviews with programme participants, direct author observation at related meetings and internal documents and correspondence.     

Space law conference 2001 : Legal challenges and commercial opportunities for Asia

Many eminent space lawyers gathered in Singapore to attend the first space law conference to be held in South East Asia. Topics for discussion—which included commercialization of space activities and its effect on the needs of developing countries, and the legal issues of expanding communications and navigation satellite services—were of particular interest to the region. This report summarizes the presentations in each session and presents the conclusions and recommendations—such as the need for a legal instrument to regulate remote sensing—produced.     

Export control regime for space items in China: Opportunities and challenges in the new era

Export control system is vital to effective control of sensitive items and technologies and thus an appropriate system is indispensable to the realization of the goal of non-proliferation. The progress so far shows that China has made great efforts in constructing a domestic regime for export controls. Nevertheless, it has also been recognized that the mere existence of a domestic regime is not sufficient and that the realization of export control should be complemented with effective and efficient enforcement. The paper examines the effectiveness of the current export control regime in China and explores means to strengthen the current regime to dispel the concerns from other nations. The paper concludes that China has been committed to export controls in sensitive space items in the past years; yet further improvements could be made to better serve China's national interests and its commitments under international nonproliferation export control regimes.     

Overview of the legal and policy challenges of orbital debris removal

Much attention has been paid recently to the issue of removing human-generated space debris from Earth orbit, especially following conclusions reached by both NASA and ESA that mitigating debris is not sufficient, that debris-on-debris and debris-on-active-satellite collisions will continue to generate new debris even without additional launches, and that some sort of active debris removal (ADR) is needed. Several techniques for ADR are technically plausible enough to merit further research and eventually operational testing. However, all ADR technologies present significant legal and policy challenges which will need to be addressed for debris removal to become viable. This paper summarizes the most promising techniques for removing space debris in both LEO and GEO, including electrodynamic tethers and ground- and space-based lasers. It then discusses several of the legal and policy challenges posed, including: lack of separate legal definitions for functional operational spacecraft and non-functional space debris; lack of international consensus on which types of space debris objects should be removed; sovereignty issues related to who is legally authorized to remove pieces of space debris; the need for transparency and confidence-building measures to reduce misperceptions of ADR as anti-satellite weapons; and intellectual property rights and liability with regard to ADR operations. Significant work on these issues must take place in parallel to the technical research and development of ADR techniques, and debris removal needs to be done in an environment of international collaboration and cooperation.     

The challenges and opportunities of a commercial human spaceflight mission to the ISS

ESA astronauts' ISS flight opportunities are considered as a vital source to meet the utilisation, operation and political objectives that Europe has established for participating in the International Space Station programme. Recent internal ESA assessments have demonstrated that a rate of three flights per year for European Astronauts should be maintained as a minimum objective. The current flight rate is lower than this. In order to improve this situation, in the context of the activation of the ESA ISS Commercialisation programme, ESA is developing the conditions for the establishment of commercially based human spaceflights with the financial support of both ESA and the private sector or, in the future, only the latter. ESA is working in a Partnership with the space industry to facilitate the implementation of such projects and support customers with a range of end-to-end commercial services. The opportunities and challenges of a "commercial human spaceflight", involving a member of the European Astronaut Corps, or a privately employed flight participant, are discussed here.     

On the stability of stationary motions of a system of coaxial bodies

We consider the stability of stationary motions of a model of a spacecraft as a system of coaxial bodies with small asymmetry caused by the shift of the axes of dynamic symmetry of bodies relative to the axis of rotation. We determine the stationary motions of the system; their stability is studied with respect to both the projections of angular velocity and the position of the axis of rotation. The sufficient conditions for the stability of these stationary motions are obtained by constructing a Lyapunov function, and the necessary conditions are obtained by analyzing the corresponding linearized equations of perturbed motion.     

On the planar inertial motion of a system of three coupled bodies

Numerous papers are devoted to studying the motion of a system (coupling) of two bodies in the Earth’s satellite orbit ([1–4] and others). The problem on the planar inertial motion of three bodies, coupled by a non-extensible weightless string having the form of an unfastened chain, is considered in the paper. Such a configuration can be represented, for example, by a system of two coupled spacecraft rotating around their common center of mass (in order to simulate the gravity force) in long-term space missions, when the third body (the lift) is located on a connecting cable. The bodies are considered to be the material points (particles).     

Global and European challenges for space law at the edge of the 21st century

An international symposium, ‘Global and European Challenges for Air and Space Law at the Edge of the 21st Century’, organised by the Institute of Air and Space Law (Cologne) and the German Aerospace Center (DLR), took place from 8 to 10 June 2005 in Cologne. The conference assembled space law experts from industry, academic and international institutions world-wide. Areas of discussion were national space legislation, the current relationship of ESA and the EU, and common issues in air and space law with regard to future aerospace applications. This report examines the common denominators underlying all these three areas.     

Manufacture in space: the MINOS system

The manufacture in Space of products for use on Earth is a possibility for the 1990s. The MINOS project is based on the idea of a free-flyer station for the current medium-level production of either unique products (which cannot be made on Earth), or of economic yields of products which cannot be obtained in sufficient quantities on Earth.At present, only the main system may be defined from general specifications: electrical power (10 kW), residual acceleration (10^?5 g), processing cycle duration (10 hr).The launch vehicle is Ariane I and its improved versions (models II, III and IV).The outer structure of the spececraft is described with solar panels, energy storage (battery and inertial storage) and control systems.The definition of orbital parameters capable of accommodating the basis specifications, especially the high energy level and the re-entry conditions on the Guiana base, is a major problem. The re-entry vehicle is studied from a pure ballistic trajectory point of view. From the results of orbital performance, the mass of the spacecraft and also the mass of the ascent vehicle are evaluated. For this latter value, its determination is directly related to the cost of space-processed materials.A general overview is given of the other spacecraft sub-systems such as satellite tracking, communications, ground stations, resources requirements, telemetry, onboard computing system etc.     

On the possibility of existence of an additional source of anomalous cosmic rays outside the solar system

On the basis of experimental data obtained at exposure of solid-state track detectors in the magnetosphere of the Earth during solar flares and in quiet Sun periods, an estimate of possible contribution of singly charged oxygen ions to the flare particle fluxes is made. A possibility is considered of the appearance in the vicinity of the solar system of singly ionized oxygen ions generated on stars.     

The economic and social benefits of space communication : A global overview of past, present and future applications

This study takes two different approaches to trying to estimate the ‘worth’ of satellite applications, one based upon tariff services and their pyramidal value and the other of estimating derived benefits on a sector-by-sector basis to total the economic value of business and application satellite services. These procedures result in an order-of-magnitude estimate for direct and indirect benefits of satellites of $390 billion per year or about 2% of the global economy. Estimations of social benefits are more difficult to quantify. The business, cultural, social and educational benefits of satellite communications are shown to be tremendous, and wherever possible clear economic terms are used.     

浅析企业与员工的长期心理契约——职业生涯管理

本文对企业员工的职业生涯管理进行了探讨与研究,从企业职业生涯管理和个人职业生涯管理相结合的角度,系统阐述了员工职业生涯初期、成长期、成熟期、晚期各个不同阶段的个体身心特点、职业需求特点、职业发展任务,以及企业实施职业生涯管理的措施.     

On the arc length of observations of a small solar system body sufficient to classify it as hazardous

This paper analyzes the accuracy of orbit determination calculated by observations of short arcs. In this case, we imposed the condition that the arc length and/or the distribution of arc observations should provide a confident classification of the orbit of a small celestial body allowing one to distinguish a potentially hazardous body, also including a threat of collision.     

Missions to the outer solar system and beyond

A report on the second IAA symposium on realistic near-term advanced scientific space missions, held in Aosta, Italy, 29 June-1 July 1998. Though some might find the idea of interstellar travel far-fetched, the question it raises of the need for a space-based infra-structure and economy is pertinent to a growing number of today's activities.