Priorities in space for the USA

This article follows the story of Shuttle development, in the context of the history of the US space programme from Apollo to the Space Station. The Shuttle was chosen as one of a series of ‘space spectaculars’ and has proven to be prohibitively expensive and unreliable, practical only for a very limited number of specialized missions. The Space Station, too, cannot be economically supplied, even if the USA could afford to build it. The author concludes that NASA should cancel the Space Station and the replacement orbiter for Challenger, and engage on a major programme of launch vehicle development, independent of the US military. The aim should be a dramatic reduction of launch vehicle costs, making spaceflight practical, and a truly independent NASA which could restore the USA to space preeminence.     

发展X-37B空间飞机的背后动因分析

文章通过对X-37B飞行器的飞行试验任务分析,指出了X-37B飞行器不是空天飞机,也不是全球快速打击平台,而是一种低成本太空进入能力的飞行验证器,它的作用定位在空间而不是在空中。通过飞行试验和验证试验,旨在打造一个可重复使用的轨道转移运载器。将美国2010年航天战略的重大调整、国际空间站的运行延期和航天飞机退役等事件结合起来,对X-37B发展的背后动因进行分析,有助于了解美国航天发展的未来趋势。经过动因的详尽分析,指出要特别关注美国航天战略调整的两个重心转向,尤其是两个转向背后的动机。如何正确地认识国际空间站的作用定位,对于审视载人航天的未来发展有重要意义。美国航天战略的调整使载人航天的重心回到近地轨道上。基于中国目前的能力现实,建议中国的载人航天重心放在地球轨道上,做好各种能力的建设,并利用这些能力把地球轨道上的事做得更好。     

How far – if at all – should the USA cooperate with China in space?

China has engaged in a steady, long-standing effort to build and strengthen its space capabilities, achieving progressively more ambitious milestones and staking its claim as a major space power. It is also increasingly engaging in cooperative efforts. A number of issues must be weighed, however, before the USA should consider any collaboration with it. These include the essentially military nature of China’s space program, the fact that China’s intentions in space and decision-making process are far from ‘transparent’, and the way it uses its space activities to pursue foreign policy goals. While the latter could be useful in, e.g., reducing tensions on the Korean peninsular through a space-services-for-giving-up-missiles tradeoff, and while there is scope for collaboration in space science missions, there are no compelling reasons for the USA to pursue cooperation in human spaceflight with China.     

Why space exploration should be a global project

Apollo should not serve as a model for the many programs for lunar and planetary exploration currently making headway: it was a unilateral effort whose generous budget would be inconceivable today. Yet President Kennedy was an advocate of cooperation in major space missions, an attitude that makes perfect sense today, when so many agencies have ambitious exploration plans. The importance of President G.W. Bush's ‘Vision for Space Exploration’, by providing a focus for NASA and others, has been underestimated. It should give us a chance to find out whether a long-term objective of moving humans off the home planet is really feasible—surely the point of exploration.     

The Brazilian space program: a selective strategy for space development and business

This report describes the Brazilian Space Organization, the country's general national needs in space and the missions in progress. During the last two decades significant investments were made in space systems development, infrastructure and human preparation. Therefore this effort must show clear benefits to justify its continuation. The way to achieve benefit is to define missions which strategically harmonize Brazil's technical indigenous capabilities and its needs.     

A gateway for human exploration of space? The weak stability boundary

NASA's plans for future human exploration of the Solar System describe only missions to Mars. Before such missions can be initiated, much study remains to be done in technology development, mission operations and human performance. While, for example, technology validation and operational experience could be gained in the context of lunar exploration missions, a NASA lunar program is seen as a competitor to a Mars mission rather than a step towards it. The recently characterized weak stability boundary in the Earth–Moon gravitational field may provide an operational approach to all types of planetary exploration, and infrastructure developed for a gateway to the Solar System may be a programmatic solution for exploration that avoids the fractious bickering between Mars and Moon advocates. This viewpoint proposes utilizing the concept of Greater Earth to educate policy makers, opinion makers and the public about these subtle attributes of our space neighborhood.     

The space elevator in the context of current space exploration policy

The space elevator is an advanced space transportation system that someday could replace chemical rockets as humanity's primary means of reaching Earth's orbit. However, before this can occur, a number of enabling technologies will need to be developed, and a variety of economic and policy questions must be addressed. The goal of this paper is to examine the feasibility of the space elevator in the context of current space exploration policy. The paper reviews the space elevator's critical enabling technologies and presents their wide variety of applications. The challenges of funding the space elevator and of building support for the program are discussed. The potential for international cooperation is considered, and the role of the space elevator in the Vision for Space Exploration is examined. The paper argues that each of the space elevator's component technologies ought to be developed independently to meet separate nearer-term objectives. The space elevator should be just one of many applications considered in making decisions to pursue research and development related to each component technology. The enabling technologies, once mature, might eventually be integrated in the construction of a full-scale space elevator from the Earth's surface to geosynchronous orbit and beyond.     

Piloted operations at a near-Earth object (NEO)

In late 2006, NASA's Constellation Program sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth object. NEOs are asteroids or comets that have perihelion distances less than or equal to 1.3 astronomical units, and can have orbits that cross that of the Earth. Therefore, the most suitable targets for the Orion Crew Exploration Vehicle (CEV) are those NEOs in heliocentric orbits similar to Earth's (i.e. low inclination and low eccentricity). One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure of the United States Space Exploration Policy and is highly complementary to NASA's planned lunar sortie and outpost missions circa 2020. A human expedition to a NEO would not only underline the broad utility of the Orion CEV and Ares launch systems, but would also be the first human expedition to an interplanetary body beyond the Earth–Moon system. These deep space operations will present unique challenges not present in lunar missions for the onboard crew, spacecraft systems, and mission control team. Executing several piloted NEO missions will enable NASA to gain crucial deep space operational experience, which will be necessary prerequisites for the eventual human missions to Mars.Our NEO team will present and discuss the following:

• •new mission trajectories and concepts;
• •operational command and control considerations;
• •expected science, operational, resource utilization, and impact mitigation returns; and
• •continued exploration momentum and future Mars exploration benefits.

     

Piloted operations at a near-Earth object (NEO)

In late 2006, NASA's Constellation Program sponsored a study to examine the feasibility of sending a piloted Orion spacecraft to a near-Earth object. NEOs are asteroids or comets that have perihelion distances less than or equal to 1.3 astronomical units, and can have orbits that cross that of the Earth. Therefore, the most suitable targets for the Orion Crew Exploration Vehicle (CEV) are those NEOs in heliocentric orbits similar to Earth's (i.e. low inclination and low eccentricity). One of the significant advantages of this type of mission is that it strengthens and validates the foundational infrastructure of the United States Space Exploration Policy and is highly complementary to NASA's planned lunar sortie and outpost missions circa 2020. A human expedition to a NEO would not only underline the broad utility of the Orion CEV and Ares launch systems, but would also be the first human expedition to an interplanetary body beyond the Earth–Moon system. These deep space operations will present unique challenges not present in lunar missions for the onboard crew, spacecraft systems, and mission control team. Executing several piloted NEO missions will enable NASA to gain crucial deep space operational experience, which will be necessary prerequisites for the eventual human missions to Mars.Our NEO team will present and discuss the following:

• new mission trajectories and concepts;

• operational command and control considerations;

• expected science, operational, resource utilization, and impact mitigation returns; and

• continued exploration momentum and future Mars exploration benefits.

Rationale and systems architecture for a near-term human lunar return

Early human missions to the Moon have landed on six different sites on the lunar surface. These have all been in the low-latitude regions of the near side of the Moon. Early missions were designed primarily to assure crew safety rather than for scientific value. While the later missions added increasingly more challenging science, they remained restricted to near-side, low-latitude sites. Since the 1970s, we have learned considerably more about lunar planetology and resources. A return within the next five to ten years can greatly stimulate future human space exploration activities. We can learn much more about the distribution of lunar resources, especially about hydrogen, hydrated minerals, and water ice because they appear to be abundant near the lunar poles. The presence of hydrogen opens the possibility of industrial use of lunar resources to provide fuel for space transportation throughout the solar system.This paper discusses the rationale for near-term return of human crews to the Moon, and the advantages to be gained by selecting the Moon as the next target for human missions beyond low-Earth orbit. It describes a systems architecture for early missions, including transportation and habitation aspects. Specifically, we describe a primary transportation architecture that emphasizes existing Earth-to-orbit transportation systems, using expendable launch vehicles for cargo delivery and the Space Shuttle and its derivatives for human transportation. Transfer nodes should be located at the International Space Station (ISS) and at the Earth-Moon L1 (libration point).Each of the major systems is described, and the requisite technology readiness is assessed. These systems include Earth-to-orbit transportation, lunar transfer, lunar descent and landing, surface habitation and mobility, and return to Earth. With optimum reliance on currently existing space systems and a technology readiness assessment, we estimate the minimum development time required and perform order-of-magnitude cost estimates of a near-term human lunar mission.     

Article

This is a slightly edited version of the Executive Summary of a joint report on cooperation in space science produced by the Space Studies Board of the USA National Research Council and the European Space Science Committee of the European Science Foundation. Using analysis of 13 case-study missions it reviews 30 years of joint missions and makes 14 recommendations based on its findings. These include the importance of setting a scientific rationale for each mission and of ensuring that objectives are shared by engineers and others involved in it, the need for independent periodic assessments and that all agreements should specify the scope, expectations and obligations of the respective agencies and relevant partners.The USA and Europe have been cooperating in space science for more than three decades. This history of cooperation has survived significant geopolitical, economic and technological changes, such as the end of the Cold War, the pressure of budget reductions and the increasing focus on economic competition and the global marketplace. Both Europe and the USA have learned from one another and acquired a knowledge base as well as an infrastructure to implement joint missions and research activities. More importantly, the decades of cooperative space research efforts between the USA and Europe have built a community of scientists whose joint scientific exchanges have established a heritage of cooperation on both sides of the Atlantic.The scientific fruits of this heritage are plainly evident in achievements such as a signature for supermassive black holes provided by the Hubble Space Telescope (HST); the first views of the solar atmosphere and corona illuminated by the Solar and Heliospheric Observatory (SOHO); the sharing of expensive research facilities on the International Microgravity Laboratory (IML); and the impressive data on ocean altimetry from the Ocean Topography Experiment (TOPEX-POSEIDON) mission, which is significantly improving our understanding of global ocean circulation.There were no guideposts for the emergence of space science cooperation between Europe and the USA. In the process of introducing new procedures and improvements to facilitate cooperation, missteps occurred, and there were political, economic and scientific losses. This report takes stock of US–European history in cooperative space endeavors, the lessons it has demonstrated and the opportunities it suggests to enhance and improve future US–European cooperative efforts in the sciences conducted in space.     

火星载人探测中辐射防护综述

火星探测是人类太空探索的重要组成部分,火星载人探测中航天员的辐射安全问题是人们最为关心的问题。文章扼要介绍了美国/俄罗斯火星载人探测技术的发展过程,重点阐述了探测中的辐射环境、辐射效应以及国外探测结果;在此基础上,对火星探测中的辐射剂量进行了预示,提出了辐射防护建议。     

立方体纳卫星的发展及其启示

介绍了立方体纳卫星的发展概况;对“震动卫星”、Cute系列、“加拿大先进纳太空实验”卫星和Coral卫星平台等典型项目进行了分析,重点对立方体纳卫星的任务、姿态与轨道控制、电源系统、通信系统、星载综合电子和可靠性等方面进行了总结。结合立方体纳卫星快速发展的原因,提出了以下建议：结合在轨服务、深空探测和新技术空间飞行演示试验等应用需求,发展微电子技术、微机电系统技术的航天应用、微卫星平台技术和标准化辅载荷发射接口技术。     

Space commercialization: Lessons from history

Private enterprise seeks to undertake virtually any activity that is institutionally and technologically feasible and that promises a high return on investment. Commercial activities in space would seem to be no exception. Indeed, it is reasonable to expect that, at some future date, commercial activities in space will overshadow government-sponsored research and military activities combined. But this date remains well into the future, it is highly uncertain, and it depends on government policies. Two major factors inhibiting further space commercialization are the current lack of necessary infrastructure and the lack of viable commercial activities. The necessary infrastructure is developing with the increasing operational status of the Space Shuttle and plans for a space station. It remains, however, to place increasing emphasis on the conduct of research in space to identify valid commercial uses of space.     

非柔性结构太空梯的构想

文章简略介绍太空梯的概念,概述了目前世界上太空梯系统的状况和研制遇到的普遍困难.由于现有的纳米技术和材料以及加工水平还不能满足缆绳式太空梯的要求,因此文章提出建造一种非柔性结构的太空梯的构想,这样的太空梯虽然运行效率不及缆绳式太空梯,但所要求的材料相对容易得到.     

Space for defence: A European vision

A common European defence policy is still at a very preliminary stage, and although some limited progress has recently been made, it is a politically sensitive issue. In contrast to scientific research or large industrial ventures such as aircraft development, where Europe has moved forward rather well, obstacles to further integration in defence and security matters are numerous. Space systems could be used to facilitate such integration as their duplication is costly and so much remains to be done in Europe in this field. A common European ‘vision’ for the role of space systems in security and defence thus needs to be developed. This article reviews the role of space in security and defence missions, the technology and industrial base Europe needs, and its capability and autonomy in achieving access to space. Space system vulnerability and the means of minimizing it are addressed, including measures to prevent the weaponization of space. The possible role of ESA in support of the European Defence Agency for defence space systems development is identified, along with the need for ad hoc organizations for operational exploitation. Ten recommendations are made that would permit progress at the European level, following the path already successfully achieved in the civilian domain.     

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.     

Earth observation from space – The issue of environmental sustainability

Remote sensing scientists work under assumptions that should not be taken for granted and should, therefore, be challenged. These assumptions include the following:1. Space, especially Low Earth Orbit (LEO), will always be available to governmental and commercial space entities that launch Earth remote sensing missions.2. Space launches are benign with respect to environmental impacts.3. Minimization of Type 1 error, which provides increased confidence in the experimental outcome, is the best way to assess the significance of environmental change.4. Large-area remote sensing investigations, i.e. national, continental, global studies, are best done from space.5. National space missions should trump international, cooperative space missions to ensure national control and distribution of the data products.At best, all of these points are arguable, and in some cases, they're wrong. Development of observational space systems that are compatible with sustainability principles should be a primary concern when Earth remote sensing space systems are envisioned, designed, and launched. The discussion is based on the hypothesis that reducing the environmental impacts of the data acquisition step, which is at the very beginning of the information stream leading to decision and action, will enhance coherence in the information stream and strengthen the capacity of measurement processes to meet their stated functional goal, i.e. sustainable management of Earth resources. We suggest that unconventional points of view should be adopted and when appropriate, remedial measures considered that could help to reduce the environmental footprint of space remote sensing and of Earth observation and monitoring systems in general. This article discusses these five assumptions in the context of sustainable management of Earth's resources. Taking each assumption in turn, we find the following:(1) Space debris may limit access to Low Earth Orbit over the next decades.(2) Relatively speaking, given that they're rare event, space launches may be benign, but study is merited on upper stratospheric and exospheric layers given the chemical activity associated with rocket combustion by-products.(3) Minimization of Type II error should be considered in situations where minimization of Type I error greatly hampers or precludes our ability to correct the environmental condition being studied.(4) In certain situations, airborne collects may be less expensive and more environmentally benign, and comparative studies should be done to determine which path is wisest.(5) International cooperation and data sharing will reduce instrument and launch costs and mission redundancy. Given fiscal concerns of most of the major space agencies – e.g. NASA, ESA, CNES – it seems prudent to combine resources.     

对我国遥测技术发展的思考

近半个世纪 ,我国遥测技术的发展令人骄傲 ,它为我国“两弹一星”等重大试验的成功立下了不朽功勋 ;进入上世纪 90年代以来 ,它在规模、体制、频段等诸多方面又上了一个新台阶。进入新世纪以后 ,面临世界遥测技术发展的挑战和我国航天、导弹及常规兵器新型号试验的新需求 ,我国遥测技术应着重深入研究和重点发展空间数据系统、综合基带设备、低仰角跟踪技术、外弹道测量、多目标综合测量、机载遥测系统、遥外测综合跟踪技术和数字化检前记录等设备和技术。     

The Space Shuttle—Evaluating an American icon

The Space Transportation System (STS), for better or worse, has dominated the US space program for some 30 years and is now an American icon. The Space Shuttle orbiters have flown over 120 missions and certainly accomplished some amazing feats, including the deployment of the International Space Station (ISS), the launch and double repair of the Hubble Telescope, a number of classified missions for the US defense establishment and the cementing of international cooperation in space. As the remaining Space Shuttle orbiters head toward various museums, it is timely to look at the STS program in terms of key US space policy decisions that have paralleled the Space Shuttle’s often troubled history. This article seeks, from both a historical and a policy perspective, to assess what might have been. While noting the major accomplishments of the STS, it also identifies what can best be characterized as major lost opportunities and flawed policy decisions that have had multi-billion dollar consequences. In this regard, the US Congress, the White House, and NASA leadership have all played a role. If there have been failings, they have not been by NASA alone, but the entire US space policy leadership.