The future of human spaceflight.

After the Apollo Moon program, the international space station represents a further milestone of humankind in space, International follow-on programs like a manned return to the Moon and a first manned Mars Mission can be considered as the next logical step. More and more attention is also paid to the topic of future space tourism in Earth orbit, which is currently under investigation in the USA, Japan and Europe due to its multibillion dollar market potential and high acceptance in society. The wide variety of experience, gained within the space station program, should be used in order to achieve time and cost savings for future manned programs. Different strategies and roadmaps are investigated for space tourism and human missions to the Moon and Mars, based on a comprehensive systems analysis approach. By using DLR's software tool FAST (Fast Assessment of Space Technologies), different scenarios will be defined, optimised and finally evaluated with respect to mission architecture, required technologies, total costs and program duration. This includes trajectory analysis, spacecraft design on subsystem level, operations and life cycle cost analysis. For space tourism, an expected evolutionary roadmap will be described which is initiated by short suborbital tourism and ends with visionary designs like the Space Hotel Berlin and the Space Hotel Europe concept. Furthermore the potential space tourism market, its economic meaning as well as the expected range of the costs of a space ticket (e.g. $50,000 for a suborbital flight) will be analysed and quantified. For human missions to the Moon and Mars, an international 20 year program for the first decades of the next millennium is proposed, which requires about $2.5 Billion per year for a manned return to the Moon program and about $2.6 Billion per year for the first 3 manned Mars missions. This is about the annual budget, which is currently spend by the USA only for the operations of its Space Shuttle fleet which generally proofs the affordability of such ambitious programs after the build-up of the International Space Station, when corresponding budget might become again available.     

Decision program on asteroid threat mitigation

The Association of Space Explorers Committee on Near-Earth Objects (NEOs) and its Panel on Asteroid Threat Mitigation have prepared a decision program to aid the international community in organizing a coordinated response to asteroid impact threats. The program is described in the ASE's report, Asteroid Threats: A Call for Global Response, which will be considered by the United Nations Committee on the Peaceful Uses of Outer Space in its 2009 sessions. The findings and recommendations of this report are presented here as well as some of the major implications of the complex decision-making involved in developing a coordinated international response to the challenge of protecting the Earth from NEO impacts.     

Investigation of thermosolutally caused convection during Bridgman-growth of BiSbTe3-mixed crystals at normal and reduced gravity

BiSbTe₃-mixed crystals have been grown at normal and reduced gravity (during the MIR'97-mission) using a Bridgman-configuration of the TITUS facility. The distribution of the components in the melt, and so the homogeneity of the growing crystal, is strongly influenced by the flow in the melt even in the case of weak convection. The flow configuration in the melt especially in front of the solid-liquid phase boundary can be investigated by means of a segregation analysis of the system components and an additional Pb-dopant. The BiSbTe₃-system is because of its hydro-dynamic properties a typical representative of semiconductor melts (low Prandtl number, high Schmidt number) but there are also some special properties relating to the segregationally caused enrichment of the lighter tellurium at the phase boundary and the resulting solutal destabilities. Experimental experiences from segregation analysis have shown that the mass transport in the melt at normal gravity is mainly influenced by convective mixing determined by thermally and solutally caused buoyancy forces. Numerical simulations have been performed for the real experimentally used configurations. These simulations have shown that a strong coupling of thermal and solutal effects exists and have given axial as well as radial segregation profiles being in excellent agreement with the experimental results for the vertical normal gravity grown crystals. For micro gravity conditions a reduction of the flow velocity of more than two orders of magnitude (depending on the micro gravity level and the direction of the residual acceleration) resulting in diffusion controlled component segregation has been predicted.The results of the two micro gravity grown crystals, especially the axial and radial segregation profiles as a sensitive indicator for the flow configuration in front of the phase boundary will be given and discussed in the paper. They will be compared with the results of numerical simulations of the melt flow for the real processing parameters measured during the TITUS growth processes and with experimental as well as numerical results for vertical normal gravity grown reference Samples.     

Investigation of thermosolutally caused convection during -growth of BiSbTe3-mixed crystals at normal and reduced gravity

BiSbTe₃-mixed crystals have been grown at normal and reduced gravity (during the MIR'97-mission) using a -configuration of the TITUS facility. The distribution of the components in the melt, and so the homogeneity of the growing crystal, is strongly influenced by the flow in the melt even in the case of weak convection. The flow configuration in the melt especially in front of the solid-liquid phase boundary can be investigated by means of a segregation analysis of the system components and an additional Pb-dopant. The BiSbTe₃-system is because of its hydro-dynamic properties a typical representative of semiconductor melts (low number, high number) but there are also some special properties relating to the segregationally caused enrichment of the lighter tellurium at the phase boundary and the resulting solutal destabilities. Experimental experiences from segregation analysis have shown that the mass transport in the melt at normal gravity is mainly influenced by convective mixing determined by thermally and solutally caused buoyancy forces. Numerical simulations have been performed for the real experimentally used configurations. These simulations have shown that a strong coupling of thermal and solutal effects exists and have given axial as well as radial segregation profiles being in excellent agreement with the experimental results for the vertical normal gravity grown crystals. For micro gravity conditions a reduction of the flow velocity of more than two orders of magnitude (depending on the micro gravity level and the direction of the residual acceleration) resulting in diffusion controlled component segregation has been predicted.The results of the two micro gravity grown crystals, especially the axial and radial segregation profiles as a sensitive indicator for the flow configuration in front of the phase boundary will be given and discussed in the paper. They will be compared with the results of numerical simulations of the melt flow for the real processing parameters measured during the TITUS growth processes and with experimental as well as numerical results for vertical normal gravity grown reference Samples.     

Developing the next phase in NASAs satellite communications program

NASAs early efforts in satellite communications development brought confidence in space technology use for improved telecommunications. New, worldwide satellite communications systems have resulted, and are now on a commercial, self-sustaining operational basis. Since 1973, NASA has conducted hundreds of user experiments and demonstrated newer technology using ATS-1, -3, -6 and CTS. Now, projections show that the commercial demand will continue to increase, soon exceeding the current technology's capacity.As a result, U.S. Space Policy affirmed in 1978 that NASA should embark again on a research and development program for satellite communications with specific, characterized goals. The resulting plan's elements include $\text{30}\text{20}\text{GHz}$ Ka-band technology, extending the current work in advanced multi-beam antennas; a narrowband system and technology study that could lead to mobile and transportable communications developments; and studies of future uses of technology in communications. The program plan and its evolution are described, followed by a report of current progress and future expectations.     

How the science and engineering of spaceflight contribute to understanding the plasticity of spinal cord injury.

Space programs support experimental investigations related to the unique environment of space and to the technological developments from many disciplines of both science and engineering that contribute to space studies. Furthermore, interactions between scientists, engineers and administrators, that are necessary for the success of any science mission in space, promote interdiscipline communication, understanding and interests which extend well beyond a specific mission. NASA-catalyzed collaborations have benefited the spinal cord rehabilitation program at UCLA in fundamental science and in the application of expertise and technologies originally developed for the space program. Examples of these benefits include: (1) better understanding of the role of load in maintaining healthy muscle and motor function, resulting in a spinal cord injury (SCI) rehabilitation program based on muscle/limb loading; (2) investigation of a potentially novel growth factor affected by spaceflight which may help regulate muscle mass; (3) development of implantable sensors, electronics and software to monitor and analyze long-term muscle activity in unrestrained subjects; (4) development of hardware to assist therapies applied to SCI patients; and (5) development of computer models to simulate stepping which will be used to investigate the effects of neurological deficits (muscle weakness or inappropriate activation) and to evaluate therapies to correct these deficiencies.     

Policy assessment of the impacts of remote-sensing technology

The successful innovation and diffusion of commercial satellite enterprises may soon encroach upon the military's historic predominance in remote-sensing capabilities. The increasing world demand for remote-sensing data and services and the forces of globalization have opened unprecedented opportunities for informational and technological trade for industrialized nations, while simultaneously creating a risk to both state security and individual privacy rights. Even as scientists and international trade advocates have sought technologies to bolster information flows, the intelligence and military communities have sought to restrict technological access in the interest of national security. The tension caused by concentrating power among various levels of government is an intrinsic part of democratic government; however, remote-sensing technologies could disrupt the balance between concentrated interests (federal government officials and agencies) and diffused interests (local governments and individual citizens). This paper aims to examine holistically the opposing forces underlying the development, diffusion, and use of remote-sensing technologies. The analysis reveals the dimensions of this problem and provides insight into the efficacy of various short- and long-term government policies.     

品牌延伸的风险与防范

摘 要 品牌延伸是指尽量利用已成功的品牌来推出改进型产品或者新产品。随着品牌在市场上的成功，企业的品牌资源意识也逐渐增强，他们希望成功的品牌带来更大的收益。经品牌延伸后，不同的产品彼此共享同样的品牌名称及其品牌意义。新产品的加入不可避免地对原有的品牌意义产生影响。这种影响可能是正面的，即加强原有品牌的识别力；也可能是负面的，即削弱了原有的品牌识别力。因此，品牌延伸不是任意的，品牌的识别意义界定了延伸的方向和最终过程。这个问题成为研究品牌延伸原理和决策的基本出发点。     

The analysis of measurements of quasi-stationary electrical fields in the near-surface zone of the <Emphasis Type="Italic">Mir</Emphasis> orbital complex

The quasi-stationary electrical fields have been measured in the near-surface zone of the Kvant module of the Mir orbital complex using vibration-type sensors of the Zond-Zaryad instrument. The analysis of measurements has shown that, depending on the spacecraft’s surface section shape (an octagon), four areas of the electrical fields configuration (and of the plasma component density) were revealed in the spacecraft vicinity: a ram with angular extension of about 120° (±60°), two side areas with angular extension of about 60° each, and a wake with angular extension of about 120° (±60°). The electrical field in the ram has a small absolute value. In the side areas, the electrical field can have either a negative or positive value, and it is smaller in magnitude than that in the ram. The electrical field in the wake has a three-petal structure (and an even more complicated structure is also possible): the negative value of the field (with angular extension of about 45°), the positive value of the field (with angular extension of about 30°), and, again, the negative value of the field (with angular extension of about 45°). Absolute value of the field in the wake is at least an order of magnitude higher than that in the ram and on the side surfaces.     

High-acceleration mass drivers

After testing an early, simplified mass-driver (35 gravity acceleration) a second, designated MD2, was designed and is now operating. MD2 is of axial geometry, with individually powered drive coils of 13.1 cm diameter. Timing is derived through the interruption of light beams by the moving armature (bucket). Electric power is provided by the resonant discharge of sector capacitor banks through silicon-controlled rectifiers in a two-phase, quadrature circuit. The bucket flies in vacuum, guided by passive dynamic eddy-current magnetic forces, those currents flowing in strip conductors lining the inside of a nonconducting vacuum pipe. The initial length of MD2 is 2.5 m, divided equally into acceleration and deceleration. Nominal acceleration is 5000 m/sec². For routine testing an ohmic bucket is used. Quantitative measurements are obtained with a solid bucket carrying two superconducting coils with a current density of 25 kA/cm². A cryogenic station for cooling the bucket to liquid helium temperature is connected to the vacuum pipe. The test program, now begun, will concentrate on guidance and acceleration forces, measurement of drive shielding losses, and possible couplings of drive forces into modes of oscillation.     

Public good or commercial opportunity? Case studies in remote sensing commercialization

The US government is once again attempting to commercialize the Landsat program and is asking the private sector to develop a next-generation mid-resolution remote sensing system that will provide continuity with the thirty-year data archive of Landsat data. Much of the case for commercializing the Landsat program rests on the apparently successful commercialization of high-resolution remote sensing activities coupled with the belief that conditions have changed since the failed attempt to commercialize Landsat in the 1980s. This paper analyzes the economic, political and technical conditions that prevailed in the 1980s as well as conditions that might account for the apparent success of the emerging high-resolution remote sensing industry today. Lessons are gleaned for the future of the Landsat program.     

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.     

Human development and the conquest of space

Space age ethics are to be distinguished as a separate set of ethical concepts for several reasons: outer space constitutes a unifying element for mankind; the unique space environment has an international statute; and the impact of space science and the utilization of space technology will always have both positive and negative international consequences and repercussions. Its main objective is an immaterial output-related activity and much of its waste is equally immaterial. Space technology carries another hazard with it - the danger of domination by extrovert cultures. Proper development of space technology requires international cooperation, scientific creativity and technological innovation combined with sociopolitical, economic and cultural aims and objectives and ethical values. Norms and objectives have to take into account religious concepts, humanistic viewpoints and sociocultural criteria. The ethics of the conquest of space have to consider the benefit of all mankind and that of each single individual, group and society as complementary and of equal importance.     

基于分频段加权的加速振动试验方法

振动环境工程研究现行采用的加速试验方法中,都只考虑了加速因子与频率无关这种情形,这不仅提高了试验设备的推力要求,也增加了位移指标要求。文章提出了一种分频段加权的加速振动试验方法,即通过对低频段加速因子的权重的优化设计,实现较小的位移指标要求,且疲劳损伤累积等效。给出了基于Dirlik方法和TB方法疲劳损伤等效的加速试验设计方法和工程实现流程。针对该方法开展了应用实例的计算,结果表明:在疲劳损伤等效的前提下,显著降低了振动台的位移,且推力基本维持不变。     

The ASTROD I charging simulation and disturbances due to solar energetic particles at 0.5 AU

The electrostatic charging of ASTROD I test mass (the Astrodynamical Space Test of Relativity using Optical Devices I) will disturb its pure geodesic motion due to spurious Coulomb and Lorentz forces. The three main disturbances associated with the charging are the acceleration noise of the test mass, the coupling between the test mass and the spacecraft, the appearance of unwanted coherent Fourier components in the measurement bandwidth. By implementing the same geometry and physics models in our previous work, a positive charging rate of 9369 e⁺/s for the solar energetic particles (SEPs) event on October 19th 1989 is predicted. Based on these charging rates, we calculated the acceleration noise and stiffness associated with charging. We also compared the acceleration noises arising from Coulomb and Lorentz effects using different discharge characteristics. Although the noise due to charging exceeds the ASTROD I budget for the two events at 0.5 AU, it can be suppressed through continuous discharging. In addition to Monte Carlo uncertainty, an error of ±30% in the net charging rates was added to account for uncertainties in the primaries spectra, physics and geometry models.     

Stepping stones toward global space exploration

Several nations are currently engaging in or planning for robotic and human space exploration programs that target the Moon, Mars and near-Earth asteroids. These ambitious plans to build new space infrastructures, transport systems and space probes will require international cooperation if they are to be sustainable and affordable. Partnerships must involve not only established space powers, but also emerging space nations and developing countries; the participation of these new space actors will provide a bottom-up support structure that will aid program continuity, generate more active members in the space community, and increase public awareness of space activities in both developed and developing countries. The integration of many stakeholders into a global space exploration program represents a crucial element securing political and programmatic stability. How can the evolving space community learn to cooperate on a truly international level while engaging emerging space nations and developing countries in a meaningful way? We propose a stepping stone approach toward a global space exploration program, featuring three major elements: (1) an international Earth-based field research program preparing for planetary exploration, (2) enhanced exploitation of the International Space Station (ISS) enabling exploration and (3) a worldwide CubeSat program supporting exploration. An international Earth-based field research program can serve as a truly global exploration testbed that allows both established and new space actors to gain valuable experience by working together to prepare for future planetary exploration missions. Securing greater exploitation of the ISS is a logical step during its prolonged lifetime; ISS experiments, partnerships and legal frameworks are valuable foundations for exploration beyond low Earth orbit. Cooperation involving small, low-cost missions could be a major stride toward exciting and meaningful participation from emerging space nations and developing countries. For each of these three proposed stepping stones, recommendations for coordination mechanisms are presented.     

Technology readiness and risk assessments: A new approach

Systems that depend upon the application of new technologies inevitably face three major challenges during development: performance, schedule and budget. Technology research and development (R&D) programs are typically advocated based on argument that these investments will substantially reduce the uncertainty in all three of these dimensions of project management. However, if early R&D is implemented poorly, then the new system developments that plan to employ the resulting advanced technologies will suffer from cost overruns, schedule delays and the steady erosion of initial performance objectives. It is often critical for senior management to be able to determine which of these two paths is more likely—and to respond accordingly. The challenge for system and technology managers is to be able to make clear, well-documented assessments of technology readiness and risks, and to do so at key points in the life cycle of the program.Several approaches have been used to evaluate technology maturity and risk in order to better anticipate later system development risks. The “technology readiness levels” (TRLs), developed by NASA, are one discipline-independent, programmatic figure of merit (FOM) that allows more effective assessment of, and communication regarding the maturity of new technologies. Another broadly used management tool is of the “risk matrix”, which depends upon a graphical representation of uncertainty and consequences. However, for the most part these various methodologies have had no explicit interrelationship.This paper will examine past uses of current methods to improve R&D outcomes and will highlight some of the limitations that can arise. In this context, a new concept for the integration of the TRL methodology, and the concept of the “risk matrix” will be described. The paper will conclude with observations concerning prospective future directions for the important new concept of integrated “technology readiness and risk assessments”.     

Lessons learned from Mir--a payload perspective

Among the principal objectives of the Phase 1 NASA/Mir program were for the United States to gain experience working with an international partner, to gain working experience in long-duration space flight, and to gain working experience in planning for and executing research on a long-duration space platform. The Phase 1 program was to provide the US early experience prior to the construction and operation of the International Space Station (Phase 2 and 3). While it can be argued that Mir and ISS are different platforms and that programmatically Phase 1 and ISS are organized differently, it is also clear that many aspects of operating a long-duration research program are platform independent. This can be demonstrated by a review of lessons learned from Skylab, a US space station program of the mid-1970s, many of which were again “learned” on Mir and are being “learned” on ISS. Among these are optimum crew training strategies, on-orbit crew operations, ground support, medical operations and crew psychological support, and safety certification processes.