Societal imperatives and the need for space nuclear power and propulsion systems

The development and exploitation of nuclear power and propulsion represent certain didactic imperatives for human civilization. Among these are economic, epistemological, moral and commercial propositions. Developing space nuclear power and propulsion represents one future; the choice of not to pursue the course barring some breakthrough in physics represents a dramatically different future. The author argues that the time is now fortuitous for deployment and operation of nuclear propulsion and power, primarily nuclear electric propulsion, at significant levels, employing figures of merit that transcend simple cost models used to justify nuclear power sources in the past. The proposition is examined, in the light of US and UN restrictions, to ascertain how best to proceed. The author argues that viewpoints of certain vocal albeit uninformed public interest groups are typically self-serving and generally categorically incorrect; it can be asserted that these same groups do not truly represent the public interest at all. It is, therefore, necessary to present an even-handed assessment of both sides of the argument to determine the virtues and liabilities of embarking on such a developmental path. Given the imperatives mentioned, the author argues that nuclear power and propulsion for space systems is a societal necessity.     

Making space for history

This report summarizes the presentations given at the third annual British Rocketry Oral-History Project, held in Surrey, UK in April 2001. A wide range of papers was given (to an equally diverse audience), covering past and present developments in air and space, both military and civilian. Many of the scientists and engineers who had worked on specific projects were present and their personal reminiscences enlivened proceedings. The importance of history in understanding not only the past but also the future of space efforts was emphasized.     

Emergency and rescue considerations for manned space missions.

Man in space is totally dependent upon spacecraft systems. particularly those providing Environmental Control and Life Support (ECLS). It is therefore required that the design of manned spacecraft systems include provision for backup emergency and rescue modes of operation to insure adequate crew safety margin. This paper discusses safety, emergency and rescue provisions included in the Space Transportation System (STS), with emphasis on ECLS subsystems. Similar discussion is included for systems projected for use in future, extended duration manned space missions.     

Architectural design for space tourism

The paper describes the main issues for the design of an appropriately planned habitat for tourists in space.Due study and analysis of the environment of space stations (ISS, MIR, Skylab) delineate positive and negative aspects of architectonical design. Analysis of the features of architectonical design for touristic needs and verification of suitability with design for space habitat.Space tourism environment must offer a high degree of comfort and suggest correct behavior of the tourists. This is intended for the single person as well as for the group. Two main aspects of architectural planning will be needed: the design of the private sphere and the design of the public sphere.To define the appearance of environment there should be paid attention to some main elements like the materiality of surfaces used; the main shapes of areas and the degree of flexibility and adaptability of the environment to specific needs.     

Cost effectiveness requirements for space power stations

The concept of converting solar energy in orbital space stations and transmitting electrical power to Earth at radio frequency, is receiving increasing attention both in paper studies and experimental and development work. The projects conceived are large in scale and implications and will demand major resources in their development and deployment. In addition to the technological requirements, the problem of reaching international decisions at political levels to fund and operate such systems will be immense. It will therefore be essential to establish as accurately as possible the basic parameters which will lead to a viable project, particularly with regard to economics.

This paper, therefore, examines the requirements which together will determine the appropriate levels of cost effectiveness of space power stations and should assist in establishing critical or sensitive areas which will influence the operational validity of the concepts. The r.f. transmission of electric power to and from, or between, spacecraft may itself have wider implications and is another aspect considered in the paper.

In summary, the paper does not seek to introduce new design concepts, but appraises the situation and exposes indicators concerning cost effectiveness.     

Microwave policy issues for solar space power

This article reviews the three major policy issues likely to arise from an SSP system: environmental safety, frequency allocation and prevention of interference with other frequency-using activities. Supporters of SSP must make sure that their case is heard clearly at the ITU, but they must also do more to promote public awareness of the technology's potential benefits in order to counter inappropriate use of the Precautionary Principle by anti-technology groups. The strengthening of standard-setting groups world-wide will also assist this process.     

Quality management for space systems in ISRO

In a little over four decades, the Indian Space Program has carved a niche for itself with the unique application driven program oriented towards National development. The end-to-end capability approach of the space projects in the country call for innovative practices and procedures in assuring the quality and reliability of space systems. The System Reliability (SR) efforts initiated at the start of the projects continue during the entire life cycle of the project encompassing design, development, realisation, assembly, testing and integration and during launch. Even after the launch, SR groups participate in the on-orbit evaluation of transponders in communication satellites and camera systems in remote sensing satellites. SR groups play a major role in identification, evaluation and inculcating quality practices in work centres involved in the fabrication of mechanical, electronics and propulsion systems required for Indian Space Research Organization's (ISRO's) launch vehicle and spacecraft projects. Also the reliability analysis activities like prediction, assessment and demonstration as well as de-rating analysis, Failure Mode Effects and Criticality Analysis (FMECA) and worst-case analysis are carried out by SR groups during various stages of project realisation. These activities provide the basis for project management to take appropriate techno-managerial decisions to ensure that the required reliability goals are met. Extensive test facilities catering to the needs of the space program has been set up. A system for consolidating the experience and expertise gained for issue of standards called product assurance specifications to be used in all ISRO centres has also been established.     

Transformation: Structure/space studies in bionics and space design

This paper discusses the architectural design project “Transformation Structure Space”, which was carried out at the Department of Building Construction HB2 in 2004. The goal of the study was to find innovative solutions for space system design through the application of bionic (biomimetic) approaches. Using specific research both fields as the foundation, five different architectural projects based on a scientific-technological concept were developed. The introduction of natural role models into the design process and the development of the application in space and the respective setting proved to be a difficult task within the timeframe of a design program, nonetheless all of the projects show very innovative aspects.     

Optimization of space orbits design for Earth orbiting missions

In Earth orbiting space missions, the orbit selection dictates the mission parameters like the ground resolution, the area coverage, and the frequency of coverage parameters. To achieve desired mission parameters, usually Earth regions of interest are identified and the spacecraft is maneuvered continuously to visit only these regions. This method is expensive, it requires a propulsion system onboard the spacecraft, working throughout the mission lifetime. It also requires a longer time to cover all the regions of interest, due to the very weak thrust forces compared to that of the Earth's gravitational field. This paper presents a methodology to design natural orbits, in which the regions of interest are visited without the use of propulsion systems, depending only on the gravitational forces. The problem is formulated as an optimization problem. A genetic algorithm along with a second order gradient method is implemented for optimization. The design process takes into consideration the gravitational second zonal harmonic, and hence allows for the design of repeated Sun-synchronous orbits. The field of view of the payload is also taken into consideration in the optimization process. Numerical results are presented that demonstrates the efficiency of the proposed method.     

空间核动力技术概览与发展脉络初探

在概略介绍现有技术方案基础上,初步探讨空间核动力技术的发展脉络,并分析其未来发展方向.基于固体核反应堆的空间核电源、核电推进及核热推进,是经过试验验证可行、具有一定技术基础并可预期实现空间应用的空间核动力技术.更先进的概念方案包括:基于气体核反应堆的核电源/核热推进、脉冲核爆推进、核裂变碎片推进等,它们的性能逐代跨越直至逼近理论极限.要充分利用核能的潜力,一方面需要提高单位质量核燃料的核能释放率,另一方面也需要减少核反应产物动能转换为无轨热运动的比率.核能潜力的充分利用需要以增加系统质量为代价.为满足未来宽广的空间任务需求,多物理机制驱动的大深度变工况一体化核能空间动力系统是未来必然发展趋势.     

Bioconversion systems for food and water on long term space missions

An imperative for prolonged Space flight missions is the conservation of resources. Extensive resupply could pose technological and logistical challenges for those responsible for the management and successful completion of the mission. Therefore, the biological waste water reclamation system (BWWR) which requires little or no expendable supplies and the waste cellulose to edible mushroom conversion system (CMCS) which is conceived as a low energy crop waste recycling system are prototype instruments which have been conceived as solutions to the mission resupply problem. Out tests, conducted with relatively crude devices based on the original concepts, indicate that further research on the basic principles underlying the systems and refinement of the engineering designs will lead to hardware with the potential to satisfy the requirement for minimal re-supply while providing recycled water and edible mushrooms.     

Venus surface power and cooling systems

A mission to the surface of Venus would have high scientific value, but most electronic devices and sensors cannot operate at the 450 °C ambient surface temperature of Venus. Power and cooling systems were analyzed for Venus surface operation. A radioisotope power and cooling system was designed to provide electrical power for a probe operating on the surface of Venus. For a mission duration of substantial length, the use of thermal mass to maintain an operable temperature range is likely impractical, and active refrigeration may be required to keep components at a temperature below ambient. Due to the high thermal convection of the high-density atmosphere, the heat rejection temperature was assumed to be at a 500 °C radiator temperature, 50 °C above ambient. The radioisotope Stirling power converter designed produces a thermodynamic power output capacity of 478.1 W, with a cooling power of 100 W. The overall efficiency is calculated to be 23.36%. The mass of the power converter is estimated at approximately 21.6 kg.     

Flexibility in system design and implications for aerospace systems

The purpose of this paper is to review the concept of flexibility as discussed in various fields of investigations, to extract its characteristic features, and to explore its implications in the case of aerospace system design. In order to discuss any subject matter clearly, it is necessary to begin with a clear set of definitions. Indeed much can be gained through careful and consistent definitions of terms alone. Flexibility however is a word rich with ambiguity. While it is being increasingly used in various fields, few attempts have been made to formally define, quantify, and propose ways for achieving flexibility. This paper proposes to fill in part of this gap by synthesizing a clear and consistent definition of flexibility. It will do so by reviewing the usage of the term in various fields of inquiries, and show that it is indeed possible to clearly and unambiguously characterize flexibility, and to disentangle it from closely related concepts.     

Net electric power of concentrating solar mirror systems for application in space as a function of the distance to the sun

The use of solar radiation by means of concentrating solar mirror systems, such as parabolic and spheric configurations, mainly is an engineering problem. A decisive characteristic for the optimisation of a complete system with turboelectric power conversion is the thermal cycle applied. Besides the Carnot process, here taken up into the study as an ideal comparative process, suitable processes for the technological realisation are the Brayton process and the Rankine process. The Brayton process is a typical gas turbine process using only the gaseous phase. The Rankine process is a steam engine process using liquid and gaseous phase.The work in hand shows how such solar systems with turboelectric conversion are optimised with respect to their specific weight (kg/kW_e) and how the distance to the sun as well as technological data enter into the analysis.As expected, the Carnot cycle as an ideal comparative process for both types of systems shows the best results for the optimum specific mass of the system. Regarding the real processes, the Rankine cycle shows more favourable characteristics than the Brayton cycle. The difference of the specific masses of the real processes mainly results from the different thermal conditions at the radiator.The influence of the distance to the sun is as expected. The nearer to the sun the solar power system operates, the better is the optimum specific mass of the system. For distances to the sun between 0.3 and 1.0 AU the spheric system shows a better behaviour than the parabolic system. For distances to the sun greater than 2.0 AU the parabolic system shows better behaviour of the specific weight. In the region between 1 and 2 AU the better optimum specific mass of the system belongs to the technological data used in the analysis.     

Force and power characteristics of a resistive exercise device for use in space

We have developed a non-gravity dependent mechanical device, which provides resistance during coupled concentric and eccentric muscle actions, through the inertia of a spinning fly-wheel (Fly-Wheel Ergometry; FWE). Our research shows that lower-limb FWE exercise can produce forces and thus muscular stress comparable to what is typical of advanced resistance training using free weights. FWE also offers greater training stimuli during eccentric relative to concentric muscle actions, as evidenced by force and electromyographic (EMG) measurements. Muscle use of specific muscle groups, as assessed by the exercise-induced contrast shift of magnetic resonance images, is similar during lower-limb FWE and the barbell squat. Unlike free-weight exercise, FWE allows for maximal voluntary effort in each repetition of an exercise bout. Likewise, FWE exercise, not unassisted free-weight exercise, produces eccentric "overload". Collectively, the inherent features of this resistive exercise device and the results of the physiological evaluations we have performed, suggest that resistance exercise using FWE could be used as an effective exercise counter-measure in space. The flywheel principle can be employed to any exercise configuration and designed into a compact device allowing for exercises stressing those muscles and bone structures, which are thought to be most affected by long-duration spaceflight.     

Optimisation of powerful energy supply systems for application in space

In this paper it is shown how a nuclear power system with turboelectric conversion is being optimised for application in space and how data subject to the mission and technological data enter into such an analysis. Thereafter it follows a comparison with nuclear power systems with magnetofluiddynamic and thermionic converters.     

日本空间力量建设现状和发展研究

日本空间力量长期以来藏军于民,但却拥有宏大的工业基础和雄厚的技术支撑,空间“动员能力”很强.重点对日本空间力量部署和作战能力进行了研究,对空间力量发展规律提出看法,为应对日本国家安全战略转变提供了参考.     

Smaller states and the new balance of power in space

The number of states capable of building, launching and operating satellites has grown significantly over the years. This article discusses how going to space in an egalitarian fashion may influence the current state of affairs related to the militarization and weaponization of outer space, the security postures of the already established space powers, and the global balance of power in general. Potential changes in the relationship between old and new spacefarers may instigate an entire shift in the understanding of threats and opportunities for international cooperation in space.