The cost benefits of the Spacelab system to scientific investigations and space applications

In the past, one of the major problems in performing scientific investigations in space has been the high cost of developing, integrating, and transporting scientific experiments into space. The limited resources of unmanned spacecraft, coupled with the requirements for completely automated operations, was another factor contributing to the high costs of scientific research in space. In previous space missions after developing, integrating and transporting costly experiments into space and obtaining successful data, the experiment facility and spacecraft have been lost forever, because they could not be returned to earth. The objective of this paper is to present how the utilization of the Spacelab System will result in cost benefits to the scientific community, and significantly reduce the cost of space operations from previous space programs.The following approach was used to quantify the cost benefits of using the Spacelab System to greatly reduce the operational costs of scientific research in space. An analysis was made of the series of activities required to combine individual scientific experiments into an integrated payload that is compatible with the Space Transportation System (STS). These activities, including Shuttle and Spacelab integration, communications and data processing, launch support requirements, and flight operations were analyzed to indicate how this new space system, when compared with previous space systems, will reduce the cost of space research. It will be shown that utilization of the Spacelab modular design, standard payload interfaces, optional Mission Dependent Equipment (MDE), and standard services, such as the Experiment Computer Operating System (ECOS), allow the user many more services than previous programs, at significantly lower costs. In addition, the missions will also be analyzed to relate their cost benefit contributions to space scientific research.The analytical tools that are being developed at MSFC in the form of computer programs that can rapidly analyze experiment to Spacelab interfaces will be discussed to show how these tools allow the Spacelab integrator to economically establish the payload compatibility of a Spacelab mission.The information used in this paper has been assimilated from the actual experience gained in integrating over 50 highly complex, scientific experiments that will fly on the Spacelab first and second missions. In addition, this paper described the work being done at the Marshall Space Flight Center (MSFC) to define the analytical integration tools and techniques required to economically and efficiently integrate a wide variety of Spacelab payloads and missions. The conclusions reached in this study are based on the actual experience gained at MSFC in its roles of Spacelab integration and mission managers for the first three Spacelab missions. The results of this paper will clearly show that the cost benefits of the Spacelab system will greatly reduce the costs and increase the opportunities for scientific investigation from space.     

What is wrong with space system cost models? A survey and assessment of cost estimating approaches

Despite several decades of research and refinement in cost estimating tools and practices, the final cost of US space programs continues to exceed initial cost estimates by an average of more than 45%. Thus, program cost models not only exhibit error, they are seriously biased. A structured review surveyed techniques, approaches, models and conceptual tools related to space program cost estimating, to understand cost in complex space systems. Analysis shows problems of cost estimating result from the growing complexity of space programs, failures in managing growth, and mission failures. Although there is greater expectation for the models to accurately predict program costs, the current models used for seeking funding for large space programs are inadequate due to (1) inability to predict future, (2) lack of insight, and (3) process replaces judgment in decision making.     

Principal investigators and project managers: Insights from Discovery

NASA’s Discovery, Explorer, and Mars Scout mission lines have demonstrated over the past 15 years that, with careful planning, flexible management techniques, and a commitment to cost control, small space science missions can be built and launched at a fraction of the price of strategic missions. Many credit management techniques such as co-location, early contracting for long-lead items, and a resistance to scope creep for this, but it is also important to examine what may be the most significant variable in small mission implementation: the roles and the relationship of the principal investigator, responsible to NASA for the success of the mission, and the project manager, responsible for delivering the mission to NASA. This paper reports on a series of 55 oral histories with principal investigators, project managers, co-investigators, system engineers, and senior management from nearly every competitively selected Discovery mission launched to date that discuss the definition and evolution of these roles and share revealing insights from the key players themselves. The paper will show that there are as many ways to define the principal investigator/project manager relationship as there are missions, and that the subtleties in the relationship often provide new management tools not practical in larger missions.     

Cost Engineering – The new paradigm for space launch vehicle design

The paper describes the basic definition and application of 'Cost Engineering' which means to design a vehicle system for minimum development cost and/or for minimum operations cost. This is important now and for the future since space transportation has become primarily a commercial business in contrast to the past where it has been mainly a subject of military power and national prestige. Several examples are presented for minimum-cost space launch vehicle configurations, such as increasing vehicle size and/or the use of less efficient rocket engines in order to reduce development and operations cost. Further a cost comparison is presented on single-stage (SSTO)-vehicles vs. two-stage launchers which shows that SSTOs have lower development and operations cost although they are larger, respectively have a higher lift-off mass than two-stage vehicles with the same performance. The design of a space tourism-dedicated launch vehicle is an extreme challenge for a cost-engineered vehicle design in order to achieve cost per seat not higher than $50,000. Finally an outlook is presented on the different options for manned Earth-to-Moon transportation modes and vehicles – another most important application of 'cost engineering', taking into account the large cost of such a future venture.     

航天器空间辐射效应分析技术现状与思考

文章梳理了面向航天器总体设计的空间辐射效应分析技术现状,重点归纳了航天器空间辐射效应分析中需关注的总剂量效应、位移损伤效应、单粒子效应分析的要素、分析方法及软件工具,并结合近年来国际上空间辐射环境模型的最新进展,就辐射环境动态变化认知、在轨辐射风险表征、陌生轨道区域辐射环境影响分析等方面提出国内空间辐射效应分析技术的不足及后续发展建议。     

法宇航卫星制造中心管理方式剖析

在介绍了法车宇航部空间防卫部及其卫星制造中心的机械设置，各部门的职责范围的基础上，重点剖析了卫星研制系统的管理特点和经验。分析认为，法国卫星研制系统的管理方法和经验值得我们学习、借鉴。     

Investigation of low-energy proton effects on aptamer performance for astrobiological applications

Biochips are promising instruments for the search for organic molecules in planetary environments. Nucleic acid aptamers are powerful affinity receptors known for their high affinity and specificity, and therefore are of great interest for space biochip development. A wide variety of aptamers have already been selected toward targets of astrobiological interest (from amino acids to microorganisms). We present a first study to test the resistance of these receptors to the constraints of the space environment. The emphasis is on the effect of cosmic rays on the molecular recognition properties of DNA aptamers. Experiments on beam-line facilities have been conducted with 2 MeV protons and fluences much higher than expected for a typical mission to Mars. Our results show that this irradiation process did not affect the performances of DNA aptamers as molecular recognition tools.     

Space manufacturing in the construction of solar power satellites

This paper deals with ongoing research work concerning energy budget and cost of the solar Satellite Power System (SPS).The fundamental model of such a total system including ground and space facilities, transportation vehicles, power satellites and rectennas is presented. The main purpose of this model is to examine the applicability of different construction scenarios to allow comparison under nearly identical constraints.Using this model in a first attempt the blankets—meaning the main part of the space segment by weight, energy investment needs and cost—are chosen representatively for the energy and cost comparison of two construction alternatives of the same SPS concept. These construction alternatives are defined just by ground and space based manufacturing of the solar blankets, while all other subsystems, operations and the transportation profiles are considered to be kept the same.It can be shown that the energy “payback” time does not only depend on the SPS concept selected but also very much on the construction and implementation scenario. The cost comparison of these alternative approaches presents not very significant differences but advantages for the space manufacturing option with potential higher differences for a less conservative approach which may apply benefits of space manufacturing meaning, for example, considerable mass savings in space.Some preliminary results are discussed and an outlook is given over the next steps to be investigated, comprising the extension of the fundamental model to include use of lunar raw materials.     

Assessing the performance of a heuristic simulated annealing algorithm for the design of distributed satellite systems

A heuristic multidisciplinary design optimization technique has been investigated for applicability to the conceptual design of distributed satellite systems. Different permutations of a simulated algorithm are applied to the problem of developing a systems architecture that minimizes a multicriterion metric (cost per image) for the NASA Origins Terrestrial Planet Finder mission. It was found that the efficiency of the simulated annealing algorithm could be improved by modifying the degrees of freedom within the algorithm. Further, a methodology has been developed for finding the Pareto-optimal set of design solutions within the system trade space when the distributed satellite system is modeled as a multi-objective design problem. These advances combine to yield new tools for systems engineers exploring the trade space of distributed satellite systems during the conceptual design stage.     

一种星载计算机数据流软故障纠正算法

在太空环境中,由于宇宙射线的存在,计算机系统的存储单元经常发生各种瞬态故障。此类故障通常都使用硬件或从系统角度加以解决,但其成本高重量大。针对此种故障类型提出了一种软件实现的数据流故障纠正算法,该算法通过对程序中变量进行简单编码和解码操作后,可对发生在程序数据空间内的单“位”错误进行检测并进而纠正。故障注入的实验结果表明,对于程序数据段错误,该算法可把错误输出从原始程序的27％～49％降低到0．01％～0．02％,同时故障纠正率接近100％;对于程序堆栈段错误,该算法可把错误输出从原始程序的10％～70％降低到1％～3％,故障纠正率也在73％以上。与其它软件实现的软故障检测或纠正算法相比,实验结果表明该算法实现简单,运算量小,具有较高的错误探测与纠正能力。     

Assessing antibody microarrays for space missions: effect of long-term storage, gamma radiation, and temperature shifts on printed and fluorescently labeled antibodies

Antibody microarrays are becoming frequently used tools for analytical purposes. A key factor for optimal performance is the stability of the immobilized (capturing) antibodies as well as those that have been fluorescently labeled to achieve the immunological test (tracers). This is especially critical for long-distance transport, field testing, or planetary exploration. A number of different environmental stresses may affect the antibody integrity, such as dryness, sudden temperature shift cycles, or, as in the case of space science, exposure to large quantities of the highly penetrating gamma radiation. Here, we report on the effect of certain stabilizing solutions for long-term storage of printed antibody microarrays under different conditions. We tested the effect of gamma radiation on printed and freeze- or vacuum-dried fluorescent antibodies at working concentrations (tracer antibodies), as well as the effect of multiple cycles of sudden and prolonged temperature shifts on the stability of fluorescently labeled tracer antibody cocktails. Our results show that (i) antibody microarrays are stable at room temperature when printed on stabilizing spotting solutions for at least 6 months, (ii) lyophilized and vacuum-dried fluorescently labeled tracer antibodies are stable for more than 9 months of sudden temperature shift cycles (-20°C to 25°C and 50°C), and (iii) both printed and freeze- or vacuum-dried fluorescent tracer antibodies are stable after several-fold excess of the dose of gamma radiation expected during a mission to Mars. Although different antibodies may exhibit different susceptibilities, we conclude that, in general, antibodies are suitable for use in planetary exploration purposes if they are properly treated and stored with the use of stabilizing substances.     

Towards an EU industrial policy for the space sector – Lessons from Galileo

The rise of the EU as an actor in the European and world space theatres, in its various roles as initiator, owner and operator of large-scale programmes such as Galileo and GMES, has raised a number of questions with regard to industrial policy. Based on the experiences from the Galileo programme's procurement round in the Full Operational Capability (FOC) phase and on the present discussions on space industrial policy within the EU, this paper argues that, whereas the EU's political ambitions in space have been discussed and become reasonably well defined, the specific policy tools and legal instruments to put them into practice are far from complete. First, an unequivocal industrial policy for the space sector needs to be defined that reconciles the Union's political ambitions with the economic specificities of the space sector. At present, this is a work in progress, with opinions diverging between member states. Second, both logically and temporally, these policy decisions need to be translated into legal instruments that allow their implementation. This implies the development of made-to-measure funding instruments and procurement rules. We conclude by emphasising the need for a sector-specific industrial policy as an integral part of the EU's space policy.     

Thermal conductivity studies of a polyurea cross-linked silica aerogel-RTV 655 compound for cryogenic propellant tank applications in space

Silica-based aerogel is an ideal thermal insulator with a makeup of up to 99% air associated with the highly porous nature of this material. Polyurea cross-linked silica aerogel (PCSA) has superior mechanical properties compared to the native aerogels yet retains the highly porous open pore network and functions as an ideal thermal insulator with added load-bearing capability necessary for some applications. Room temperature vulcanizing rubber-RTV 655—is a space qualified elastomeric thermal insulator and encapsulant with high radiation and temperature tolerance as well as chemical resistance. Storage and transport of cryogenic propellant liquids is an integral part of the success of future space exploratory missions and is an area under constant development. Limitations and shortcomings of current cryogenic tank materials and insulation techniques such as non-uniform insulation layers, self-pressurization, weight and durability issues of the materials used, has motivated the quest for alternative materials. Both RTV 655 and PCSA are promising space qualified materials with unique and tunable microscopic and macroscopic properties making them attractive candidates for this study. In this work, the effect of PCSA geometry and volume concentration on the thermal behavior of RTV 655—PCSA compound material has been investigated at room temperature and at a cryogenic temperature. Macroscopic and microscopic PCSA material was encapsulated at increasing concentrations in an RTV 655 elastomeric matrix. The effect of pulverization on the nanopores of PCSA as a method for creating large quantities of homogeneous PCSA microparticles has also been investigated and is reported. The PCSA volume concentrations ranged between 22% and 75% for both geometries. Thermal conductivity measurements were performed based on the steady state transient plane source method.     

原子氧对航天材料的影响与防护

文章综述了低地球轨道（LEO）中原子氧（AO）环境对航天材料影响的研究现状。首先介绍AO对材料的危害及作用机制等。然后重点阐述了国内外学者关于AO与Al、Ag、Cu、Ni等金属材料以及半导体材料作用的研究成果。最后总结了AO的防护方法,及其对不同材料抗AO侵蚀能力的改善结果。     

临近空间飞行器多物理场耦合建模的网格映射方法

临近空间飞行器的研制面临许多复杂的问题和挑战,涉及总体、气动、结构、控制、防热、动力等多个学科和专业领域的相互作用、高度耦合的子系统。全系统、全流程的仿真验证与性能评估能够为设计工作提供重要依据,缩短研制周期。而气动、结构、防热等专业的仿真建模和模型解算基于有限体积法或有限元方法,依赖于不同的工具软件,且网格的划分方法不同。本文研究了临近空间高超声速飞行器多物理场耦合建模方法,研究并实现了异构网格耦合界面之间与耦合域之间的信息传递方法,从而实现了临近空间高超声速飞行器的多物理场耦合建模与仿真。     

Plastic Cubesat: An innovative and low-cost way to perform applied space research and hands-on education

This paper describes the design and the manufacturing of a Cubesat platform based on a plastic structure.The Cubesat structure has been realized in plastic material (ABS) using a “rapid prototyping” technique. The “rapid prototyping” technique has several advantages including fast implementation, accuracy in manufacturing small parts and low cost. Moreover, concerning the construction of a small satellite, this technique is very useful thanks to the accuracy achievable in details, which are sometimes difficult and expensive to realize with the use of tools machine. The structure must be able to withstand the launch loads. For this reason, several simulations using an FEM simulation and an intensive vibration test campaign have been performed in the system development and test phase. To demonstrate that this structure is suitable for hosting a complete satellite system, offering innovative integrated solutions, other subsystems have been developed and assembled.Despite its small size, this single unit (1U) Cubesat has a system for active attitude control, a redundant telecommunication system, a payload camera and a photovoltaic system based on high efficiency solar cells.The developed communication subsystem has small dimensions, low power consumption and low cost. An example of the innovations introduced is the antenna system, which has been manufactured inside the ABS structure. The communication protocol which has been implemented, the AX.25 protocol, is mainly used by radio amateurs. The communication system has the capability to transmit both telemetry and data from the payload, in this case a microcamera.The attitude control subsystem is based on an active magnetic system with magnetorquers for detumbling and momentum dumping and three reaction wheels for fine control. It has a total dimension of about 50×50×50 mm. A microcontroller implements the detumbling control law autonomously taking data from integrated magnetometers and executes pointing maneuvers on the basis of commands received in real time from ground.The subsystems developed for this Cubesat have also been designed to be scaled up for larger satellites such as 2U or 3U Cubesats. The additional volume can be used for more complex payloads. Thus the satellite can be used as a low cost platform for companies, institutions or universities to test components in space.     

航天材料基因工程及其若干关键技术

材料基因工程的理念和将空间环境与效应纳入到航天材料研制全流程的思路将对航天材料的开发带来颠覆性的革命。文章在对国内外材料基因组计划和航天材料需求分析的基础上,首先对航天材料基因工程的内涵进行阐述,进而对基于航天材料基因工程的航天材料研制流程进行分析,最后结合空间环境效应及材料基因工程,从计算工具、试验工具、数字化数据三个维度,提出空间多因素环境与航天材料的耦合作用机理、航天材料空间多因素环境效应等效评价方法、空间复杂使役环境下航天材料性能演化模型、航天材料空间环境效应数据库、基于材料基因工程的航天材料设计模型、航天材料研制的不确定性及优化方法等关键技术和发展方向。     

空间环境对光学元件分子污染的影响及减缓方法

随着航天器在轨寿命的延长,分子污染对其空间光学系统在轨安全和可靠性的影响越来越突出。文章首先阐明空间分子污染的来源及其对空间光学元件的效应;之后分析温度、紫外辐射、激光照射等空间自然环境和人工环境对光学元件分子污染的影响,揭示空间环境影响光学元件分子污染的演变过程和形态;进而给出地面预处理、表面改性、优化系统设计和在轨主动清除等方面的空间光学元件分子污染减缓与清除技术;最后提出分子污染的高灵敏监测、热控及分子污染吸附复合涂层、分子污染在轨高效去除技术、先进的协同模拟设备和仿真技术等研究方向。     

SY汇流板去毛刺技术

结合SY汇流板的结构和加工特点,采用优化加工参数、变更加工条件、改善刀具等方法控制和去除产品钻削加工过程中产生的毛刺。这几种方法经济适用,低成本高效率地应用于实际生产中。