Space batteries for mobile battlefield power applications

A review of space power systems was undertaken to identify advanced space batteries for mobile applications. State-of-the-art systems are described. The technology issues that need to be addressed in order to bring these systems along and meet the needs of the user are discussed. Future research directions are examined     

World Space Congress: a vision quest

The World Space Congress (WSC) in October, 2002, brought together luminaries, aerospace engineers, students, and scientists to discuss strategies for reviving the world's space agency. WSC lectures and plenary sessions focused on future research in space. Among topics discussed are the use of the Hubble Space Telescope to scan for habitable planets and obtain data about the beginning of the universe, new weather satellites, planetary protection from comets or asteroids, exploration and establishment of colonies on the Moon and Mars, medical advances, the role of space exploration in the world economy.     

Space power by ground-based laser illumination

Reducing energy storage requirements of space power systems by illuminating the photovoltaic arrays with a remotely located laser system is addressed. It is proposed that large lasers be located on cloud-free sites at one or more ground locations and that large lenses or mirrors with adaptive optical correction be used to reduce the beam spread due to diffraction or atmospheric turbulence. During the eclipse periods or lunar night, the lasers illuminate the solar arrays to a level sufficient to provide operating power. Two applications are discussed: illumination of geosynchronous orbit satellites and illumination of a moonbase power system. Issues for photovoltaic receivers for such a system are discussed     

Space Station power requirements and issues

This paper provides an overview of the Space Station configuration and summarizes the requirements, architecture, and significant challenges associated with the electrical power system (EPS). The Space Station configuration was baselined during the systems design review (SDR) process in March, 1994. The current configuration includes the addition of Russia as an international partner, resulting in major changes to the assembly sequence, pressurized module complement, and overall power architecture. The Russian contributions to the power system architecture, as well as an-overview and development status of the US provided elements is presented. Finally, a planned flight demonstration of solar dynamic power system on the Mir as part of the first phase of US/Russian cooperation in human space flight is described     

International Space Station power storage upgrade planned

As the Earth-orbit International Space Station (ISS) grows, it needs more power which is generated by solar panels. For periods in which the planet Earth occults sunlight, energy is stored in the biggest set of batteries ever flown in space. Reliability of power is important in a space station because a failure requires costly launch of replacement components. Even greater importance results when astronauts work in the station. A power failure that causes the astronauts to perish would be a very serious event. The first battery-containing "integrated equipment module" was launched November 30, 2000 and installed on port 6 of the International Space Station. Two more modules will be launched by the United States; to be launched in 2004 is the European Space Agency's "attached COLUMBUS APM laboratory," which will have its own power system. Unexpected battery-related events occurred in the integrated equipment module during its first year-and-a-half in orbit. The problems and their solutions were described in papers presented at the 37/sup th/ Intersociety Energy Conversion Engineering Conference. Since the International Space Station carries more battery cells than any other spacecraft, the in-flight performance data from its battery assembly can be useful to engineers who design power supplies for other spacecraft. We, therefore, summarize the battery development process, the adopted design, and an unexpected in-flight battery degradation and its correction.     

Image quality issues for an enhanced vision head up display

A part task simulation study was performed to determine the ability of pilots to land an aircraft using head up display (HUD) guidance symbology overlaying an emulated millimeter wave imagery. The task was to land in Category IIIa weather at a Category I facility. Three image parameters were varied: image update rate, image processing latency, and the luminance contrast ratio of the runway image to the background noise. ILS beam bending that was representative of a Category I facility was randomly varied across the experimental runs. Nine pilots completed the test matrix. The only variable that made a significant difference was the runway to background contrast ratio     

Design of the Space Station Freedom power system

The design of Space Station Freedom's electric power system (EPS) is reviewed, highlighting the key design goals of performance, low cost, reliability, and safety. The EPS design is divided into three separate areas: power generation and storage, power distribution, and power management and control. Both photovoltaic and solar dynamic power generation and storage systems are used. Tradeoff study results that illustrate the competing factors responsible for many of the more important design decisions are discussed. Reliability and maintainability, as well as verification and testing, are addressed     

Using natural features for vision based navigation of an indoor-VTOL MAV

The use of natural features for vision based navigation of an indoor Vertical-Take-Off-and-Landing (VTOL) Micro Aerial Vehicle (MAV) named Air-Quad is presented. Air-Quad is a small four-rotor helicopter developed at the ITE.Such a helicopter needs reliable attitude information. The measurements of the used MEMS gyroscopes and accelerometers are corrupted by strong noise. To be useful, the MEMS sensors have to be part of an integrated navigation system with aiding through complementary sensors like GPS or the computer vision module presented here.In the computer vision module, feature points are detected and tracked through the image sequence. The relative rotation and translation of the camera are estimated using the two-dimensional motion of the feature points.The three-dimensional points in the scene are modeled with the image coordinates of their first sighting and their inverse depths. Only these inverse depths are estimated for the feature points. An efficient sparse bundle adjustment algorithm is used to improve the estimation of the scene structure and the navigation solution.It is shown that the use of the computer vision module greatly improves the navigation solution compared to a solution based only on MEMS sensors.     

Space power systems requirements and issues: the next decade

Some of the more important space power technology issues, requirements, and challenges of the 1990s are described, and the impact of new component technology on the overall performance of space power systems is assessed. Advanced component, subsystem and system technologies that will significantly affect the performance, reliability, and survivability of next-generation baseload and burst mode space power systems are emphasized. Technology disciplines related to power sources (solar/nuclear and chemical), power conversion, energy storage, power conditioning/distribution and control, and waste-heat acquisition, transport, and rejection are primarily addressed. For some of them, performance trends that can be used as the basis for projecting future advanced power-system performance are developed. Performance capabilities for several different types of space power system for both baseload and burst mode applications are postulated on the basis of evolving technology and point designs that incorporate projections of advanced component capabilities     

Current status, architecture, and future technologies for theInternational Space Station electric power system

The Electric Power System (EPS) being built for the International Space Station has undergone several significant changes over the last year, as major design decisions have been made for the overall station. While the basic topology and system elements have remained the same, there are important differences in connectivity, assembly sequence, and start-up. The key drivers for these changes in architecture have been the goal to simplify verification, and most significantly, the introduction of extensive Russian participation in the program. Having the Russians join the international community in this project has resulted in an expanded station size, larger crew, and almost doubled the observable surface of the Earth covered by the station. For the power system it has meant additional interfaces for power transfer, and new challenges for solar tracking at the higher inclination orbit. This paper reviews the current architecture and emphasizes the new features that have evolved, as the design for the new, larger station has developed. Additionally, the possible application of developing technology to the station, and other future missions is considered     

Model-based vision for automatic alarm interpretation

The further development of a previously reported knowledge-based vision recognition system for automating the interpretation of alarm events resulting from a perimeter intrusion detection system (PIDS) is reported. Measurements extracted over a sequence of digitized images are analyzed to identify the cause of the alarm. Models are maintained for alarm causes, and the scene and the measurements are matched with the models to derive an appropriate classification of the event. An overview of the initial classification system is provided, and modifications to the system are described. The results of applying the system to a range of real alarm events are presented, and further improvements are discussed     

Night vision devices for ground environment

The PM N-V/RSTA is procuring the Driver's Vision Enhancer (DVE) thermal imaging system for use in combat and tactical wheeled vehicles. The DVE uses uncooled forward looking infrared technology compared to the I² technology currently in the field. During the development of the DVE several issues were raised regarding how specific aspects of system design were related to driver performance. As a result, DCS Corporation developed a data collection effort to provide the DVE project leader with needed performance data that could act as a foundation for making program decisions     

Analysis of an Out-of-Core Thermionic Space Power System

Conceptual designs of out-of-core thermionic space power generators using heat pipes have been produced for various powers, temperatures, and constraints or parameter values. Since major impediments to inpile thermionic systems are alleviated or eliminated in the out-of-core concepts, a competitive degree of feasibility and competitive specific masses are adequate to establish the need for emphasis on these systems in future studies and development activities. Feasibility in the six cases shown here in conceptual detail appears to be limited only by lithium heat-pipe feasibility and a favorable outcome of current technology development of UN, W, and Li materials in the temperature range considered. For example, one man-rated system at 300 kWe and 1800°K shows a specific mass of 8 kg/kWe and will accommodate an 18-meter payload at a 50-meter distance.     

Multiple function sensors for enhanced vision application

It is argued that enhanced vision, a system that includes sensors capable of supporting the means for safe operation in a low-visibility (fog) environment, should be part of a nested capability to provide seamless, safe, and efficient gate-to-gate operation, in any environment. It is not a stand-alone function; sensor selection criteria must support functional integration with other avionics. A modular-architecture multiple-function sensor approach to cost-effective enhanced vision system capability is described     

空间多功能在轨维护机器人系统及其末端执行器设计

空间机器人是空间在轨服务的一种重要工具。以合作目标与非合作目标的在轨维护为目的,通过对现有空间机器人研究现状的调研和分析,提出了基于末端工具可快换的多功能在轨维护机器人系统,并提出多种末端执行器设计方案。其中三指-三瓣式末端执行器作为末端工具快换装置,不仅具有机械接口捕获对接的功能,还具有电力/信号传输功能,以及机械臂动力传输功能;钢丝绳缠绕式末端执行器具有优越的容差和软捕获性能,适合用于实现对安装有捕获接口的合作目标以及非合作目标卫星发动机喷管的捕获;而欠驱动三指末端执行器具有良好的待捕获目标物体形状自适应功能以及软捕获功能,因此可用于对空间形状不规则的太空垃圾等目标进行非合作目标捕获。通过对多功能在轨维护机器人系统及其末端工具快换过程以及末端执行器对目标捕获操作的研究,所提出的基于末端工具快换的多功能在轨维护机器人系统有较好的应用前景。     

Megahertz power converters for specific power systems

Some of the problems in the development of pulsewidth power converters when the switching frequency is increased from hundreds of kilohertz to tens of megahertz are highlighted. The major goal is the establishment of a ten megahertz power chain designed to operate in a distributed system from a DC power bus of 24 to 48 V. Available components and materials are discussed, and possible topologies-flyback, forward, push-pull forward, and buck converters-are examined. The performance criteria chosen for this analysis are, in the order of preference, output requirements, size and weight, efficiency, and cost     

辅助动力装置N-Dot加速控制研究及试车验证

在辅助动力装置(APU)全权限数字电子控制系统研制中,为保证同一型号APU加速性能不受APU加工误差、部件性能衰退等的影响,采用基于N-Dot的加速控制方法对APU的过渡态加速控制律进行设计。在控制算法实现过程中,为避免纯微分在实际工作中带来的数值干扰和稳定性问题,对设计的控制回路进行了等效变换,得到了基于纯积分的加速度闭环控制的等价形式。通过台架试车,对基于N-Dot的加速控制律进行验证。试车结果表明,所设计的N-Dot加速控制律能有效防止APU在加速过程中超转、超温,且加速性能一致性良好,能有效发挥其加速性能。