Leadership in space transportation

Rather than aiming at overall preemenence in space, as in the past, it is important for the USA now to specify goals and objectives for its space programme. In the space transportation market, the USA faces long-term competition. Planned properly, the Space Shuttle, Space Station and transfer stages can be used as a unique transport system, forcing other suppliers to compete on US terms. Such a total transport service system could also include ELV support. In entering into international space agreements, the government must take into account the objective of maintaining the competitiveness of the US commercial sector.     

Evaluating NASA's role in risk communication process surrounding space policy decisions

In an effort to standardize evaluations of agency communications with stakeholders, a recent NASA report outlined the need to consider metrics that could be used to measure effectiveness over time by monitoring communications output and examining the outcome of communication activities. While evaluating agency communications in this way seems straightforward, actually carrying out such an evaluation is fraught with potential problems. This is especially true of communications surrounding risky or stigmatized activities, as evaluations of this type may lead to an overemphasis on negative participant reactions and an obscuring of those areas where competent work is being done. To help avoid this, an alternative is to conduct evaluations of the process involved in creating agency communications, rather than people's reactions to the communication programs themselves. Adopting this approach de-emphasizes the supposed requirement for researchers to correlate an individual or group's behavior with comprehension or agreement with agency communications. This paper outlines 5 criteria for such a process and discusses them in the context of an evaluation of the risk communication program surrounding the Cassini mission to Saturn.     

Tether applications in space transportation

The high cost of delivering rocket propellants to orbit for use there makes attractive the use of alternative reaction masses such as other spacecraft, planetary magnetospheres and atmospheres, light and celestial bodies. Some of these alternatives have already been used in special cases, but tethers may be the key to using all of them on a far more general and ambitious basis. This paper gives a general overview of the many ways tethers might be used in space transportation. There is an emphasis on near-term applications such as payload boosting and space station momentum management.     

Competitiveness of commercial space transportation services

Competition between the providers of space transportation has become intense with the distinct possibility of governments providing both direct and indirect subsidies in order to influence transportation user choices. This bodes well for users of transportation services but has serious ramifications with regard to the future makeup of the international space transportation industry. This paper addresses the following key issues: selecting a launch service given a decision to establish a business to provide satellite communication services; establishing the price that should be bid by a launch provider in order to have a specified chance of being awarded the launch contract; and assessing the possibility that a launch provider is utilizing unfair or predatory pricing in order to increase the likelihood of winning launch contracts and thereby increasing market share. A method is developed and results presented based upon establishing ‘value in use’ pricing that explicitly takes into account the multiple attributes of alternative launch services. This leads to an assessment of ‘predatory’ pricing in terms of the value in use pricing.     

Nuclear waste disposal in space: Implications of advanced space transportation

Previous studies have shown that the disposal of nuclear waste in space is promising as a practical and economically plausible option, based on use of the first generation space shuttle. The promise brightens if we consider use of more effective second generation systems such as fully reusable single-stage-to-orbit transports. These vehicles, with simpler more reliable flight characteristics and with operational economics at least twenty times more favorable than the first shuttle, can become available in the early 1990s when the nuclear waste problem will have grown to truly serious proportions. This paper surveys both vertical and horizontal-takeoff vehicles as they could be used for the Earth-to-orbit phase of nuclear waste disposal mission. The international nature of the nuclear waste issue is emphasized, and the suggestion is made that an international equatorial launch site be established. This launch center, apart from its inherent safety features, would serve as a focus for an international solution of the truly worldwide problem of nuclear waste disposal.     

The USA and international competition in space transportation

This article discusses the crisis facing the USA in the formulation of its space transportation policy, within the context of its overall national space policy. The author examines developments in international space transportation from 1982 to 1992, and the failure of US policies to meet foreign commercial competition in space launches. Two goals have emerged from the US policy debate: to achieve assured access to space, and to reduce the costs of sending payloads to orbit. Both goals need to be faced within the context of a wider commitment by government and private industry to space investment.     

Setting space transportation policy for the 1990s

This article is a summary of a report on space transportation policy by the US Congress's Congressional Budget Office published in October 1986. The report was written as a contribution to the discussions in the USA on national space policy after the Challenger accident.     

The private solution to the space transportation crisis

Confused and short-sighted decisions dominated by political expediency have been made about US space policy in the past 30 years. Overly large and ambitious systems have been chosen, resulting in today's crisis in space transportation. The history of commercial aircraft development offers an alternative example of producing in a range of sizes and capabilities for a wide variety of users, and shows that the space transport industry could benefit from applying the decision-making processes used in private enterprise. The authors examine strategies for privatization of space transportation and conclude that policy support for the commercial launch industry must be continued. NASA must be reoriented towards its basic research function, and more government services should be bought from the private sector.     

A forward plan for space in the UK

Below we present edited extracts from a Forward Plan recently prepared by the UK government which sets out aims and actions for the UK civil space programme. These have been developed during a process of consultation involving British National Space Centre (BNSC) partners, industry and academia which started with a forum held at Surrey University in September 1995, and culminated in the discussion of a draft Plan at the Second UK Space Policy Forum in June 1996. Crowm copyright is reproduced with the permission of the Controller of HMSO.     

Results of studies on advanced winged space transportation systems

This paper reviews advanced space transportation studies that have been conducted at the NASA Langley Research Center over the past several years and presents the impact of technology on vehicle size and weight. The focus of this work has been on systems that could become operational in the late 1990s and beyond with the primary emphasis on winged vehicles, both single-stage-to-orbit and two-stage concepts.     

NASA的“发现”计划及其进展

2004年1月美国政府公布了“空间探索远景规划”．2005年9月美国航空航天局（NASA）据此出台了“空间探索计划”。该计划的主要内容分为“科学、探测与航空”和“探测能力”两大部分。“科学、探测与航空”包括科学、探测系统和航空三项任务．     

基于成本考虑的天地往返技术途径分析

采用能量分析方法,对天地往返成本的影响因素进行了分析。重点对入轨方式、发射方法和动力系统等因素进行了分析。提出了未来天地往返运输技术的研究设想。     

The US national space transportation policy: issues for congress

Below is a summary of what was to be the first in a series of reports produced by the Office of Technology Assessment (now defunct) on policy for the USA's future space transportation technology and industrial base. It examines the Clinton Administration's 1994 National Space Transportation Policy and supporting implementation plans and raises and analyses such issues as conflicts and redundancies within NASA and DoD space transportation development programs; competition and cooperation with foreign launch vehicle and component providers; US government limits on the conversion of long-range missiles to space launchers in the face of Russian activity in this area; and the effectiveness of Administration efforts to include the private sector in space transportation decision making. Some issues not covered in the Policy are also discussed.     

The decay of NASA's technical culture

The ability of the US government to carry out future space policies depends upon the maintenance of a technically capable space flight agency. During its first decade of operation the National Aeronautics and Space Administration (NASA) developed an organizational culture supporting very high levels of reliability. This ‘technical culture’ stressed the importance of in-house technical capability, ‘hands on’ activity and extensive testing. Forces at work on the agency since 1970 have tended to erode the original culture. This article explains the ways in which the beliefs and norms guiding NASA operations have changed since the agency's first decade of operations.     

空间快速响应航天器轨道/弹道一体化规划

以空间应急响应任务为背景,采用轨道/弹道一体化规划设计方法,实现空间快速响应航天器全程飞行轨迹规划。在分析弹道设计参数对轨道参数影响性的基础上,将弹道规划分为程序角参数设计和发射诸元参数设计,采用改进的粒子群算法和牛顿迭代法进行混合优化求解。算例表明,使用混合优化求解方法收敛速度快,迭代次数少,易于工程实现,能满足一体化任务规划的快速性要求,可为空间快速响应航天器设计提供理论参考。     

奥巴马砍掉重返月球计划

美国总统奥巴马2月1日向国会提交了总额3.83万亿美元的2011财年预算方案,其中为NASA申请的预算为190亿美元。这份预算提出砍掉前任总统布什提出的以重返月球为目标的"星座"计划,将国际空间站的工作时间至少延长到2020年,并拿出数十亿美元来发展商业航天飞行器和旨在使美国能持续开展空间探测的"可改变格局的技术"。     

US space transportation policy : History and issues for a new administration

The new US administration faces complex questions on the future role of the USA in space, and tough decisions on how to pay for it. Decisions made now on space transportation will have a strong impact on US space leadership for the next decade. The author discusses the history and current state of space transportation planning, and considers the key issues which will confront the new administration.