Parametric cost model for solar space power and DIPS systems

A detailed cost model has been developed to parametrically determine the program development and production cost of photovoltaic, solar dynamic, and dynamic isotope (DIPS) space power systems. The model is applicable in the net electrical power range of 3 to 300 kWe for solar power and 0.5 to 10 kWe for DIPS. Application of the cost model allows spacecraft or space-based power system architecture and design trade studies or budgetary forecasting and cost benefit analyses. The cost model considers all major power subsystems (i.e., power generation, power conversion, energy storage, thermal management, and power management/distribution/control). It also considers system cost effects such as integration, testing, and management. The cost breakdown structure, model assumptions, ground rules, bases, cost estimation relationship format, and rationale are presented, and the application of the cost model to 100-kWe solar space power plants and to a 1.0-kWe DIPS is demonstrated     

Thermionic/AMTEC cascade converter concept for high-efficiencyspace power

This paper presents trade studies that address the use of the thermionic/AMTEC cell-a cascaded, high efficiency, static power conversion concept that appears well-suited to space power applications. Both the thermionic and AMTEC power conversion approaches have been shown to be promising candidates for space power. Thermionics offers system compactness via modest efficiency at high heat rejection temperatures, and AMTEC offers high efficiency at modest heat rejection temperature. From a thermal viewpoint, the two are ideally suited for cascaded power conversion: thermionic heat rejection and AMTEC heat source temperatures are essentially the same. In addition to realizing conversion efficiencies potentially as high as 35-40% such a cascade offers the following perceived benefits: Survivability-capable of operation in the Van Allen belts; Simplicity-static conversion, no moving parts; Long lifetime-no inherent life-limiting mechanisms identified; Technology readiness-Large thermionic database; AMTEC efficiencies of 18% currently being demonstrated, with more growth potential available; and Technology growth-applicable to both solar thermal and reactor-based nuclear space power systems. Mechanical approaches and thermal/electric matching criteria for integrating thermionics and AMTEC into a single conversion device are described. Focusing primarily on solar thermal space power applications, parametric trends are presented to show the performance and cost potential that should be achievable with present-day technology in cascaded thermionic/AMTEC systems     

Energy and power

Energy sources for aerospace systems include electrochemicals, mechanical rotation, solar illumination, radioisotopes, and nuclear reactors. Energy is converted to power with engines, turbines, photovoltaics, thermoelectric and thermionic devices, and electrochemical processes. Although some early spacecraft flew with battery power, for longer flights the choice has been either solar or nuclear. Manned spacecraft must have power for the total mission duration including boost into orbit, on-orbit, and subsequent re-entry. Batteries are too heavy for extended manned space missions; tradeoff study alternatives range from radioisotope heated thermionic converters to hyperbolic-fueled engines. Arrays of solar cells are the obvious choice for powering space stations and for other extended-duration missions. This article emphasizes developments for space and airplane power systems. Enabling technologies are described along with significant spin-offs and future systems     

Magnetic propulsion systems

Magnetic propulsion systems are based on the direct interaction of the vehicle's own magnetic field with the natural magnetic field, particularly the geomagnetic one, without using jet propulsion. Three such systems are reviewed in the order of their feasibility of automatic control over the thrust force vector. One of these magnetic propulsion systems permits partial control and is competitive with the electromagnetic or plasma rocket orbital microthrusters. The importance of the other two promising systems is to establish the main principles of magnetic propulsion. Their development depends on progress in solid-state physics. One of them may be able to have total control over the direction and modulus of the electrodynamic thrust force vector.     

Integration of Large Power Systems into Manned Space Stations

Essential design factors and system characteristics are explored for integration of large power systems into manned space stations. The impact of the type of power system selected upon the space station is outlined, as is the impact of the mission requirements upon the selection of power systems. Criteria for resolving the selection/application/ integration problems are provided. Comparisons between systems are based on recently defined space-station models for 90-day to five-year mission durations in the 1970' s, with four-to nine-man crews. Power systems encompass power levels from 3 to 50 kWe and include solar cell/battery. fuel cell, hybrid fuel cell/solar cell, radioisotope, and nuclear reactor systems. Thermoelectric, Brayton cycle, organic Rankine, and liquid-metal Rankine power conversion systems are considered for the nuclear energy sources. Both rigid and roll-out photovoltaic array configurations are analyzed with respect to the solar energy source.     

Electric space propulsion systems

Active development of electric thrustors began 10 years ago. Today, several kinds of thrustors have achieved efficiencies above 90 % and lifetimes of several thousand hours. The following article derives the basic theory of electric thrust production at constant exhaust velocity, and at variable exhaust velocity programmed for optimum vehicle performance. Electrothermal or arcjet; electrostatic or ion; and electrodynamic or plasma thrustors are described. At the present time, ion thrustors of the electron bombardment and of the surface ionization types are the most promising systems. Electric power in space may be generated by solar cells or nuclear-electric generators. It is expected that the incore thermionic converter will eventually be the preferred system. A variety of missions with electric propulsion systems appear feasible and highly desirable, among them orbital station keeping, attitude control, planetary probes, solar and out-of-the-ecliptic probes, deep-space probes, and manned Mars and Venus exploration. For each mission, a careful systems-design study must be made, which will provide the optimum selection of thrustor type, thrust level, exhaust velocity, thrust program, power source, trajectory, and flight plan.     

First Mars outpost power systems

Research into potential power systems for the First Mars Outpost (FMO) was performed. The author examined a representative mission architecture which was developed by NASA to determine power system requirements. Power system options including nuclear, isotope, photovoltaic (PV), chemical heat engine, and regenerative fuel cell (RFC) concepts were identified for potential Mars surface applications. A top-level characterization study was conducted to determine power system mass and area for each application. It is seen that PV systems are generally not suited for Mars surface applications due to the large surface area required and higher mass than a closed Brayton cycle SP100 reactor system. A reactor is currently being considered by NASA Lewis Research Center to provide power for base architectures including an ISRU (in situ resource utilization). An oxygen/methane powered heat engine would provide 40 kWe of emergency power for the habitat. A dynamic isotope power system (DIPS) is the current choice for a long-duration pressurized rover due to the excessive size of a PV/RFC system and higher mass of a heat engine system. DIPS has advantages for other low power systems due to its neatly immediate availability and flexibility (night or day power; no recharging required)     

Development of Kabila rocket: A radioisotope heated thermionic plasma rocket engine

A new type of plasma rocket engine, the Kabila rocket, using a radioisotope heated thermionic heating chamber instead of a conventional combustion chamber or catalyst bed is introduced and it achieves specific impulses similar to the ones of conventional solid and bipropellant rockets. Curium-244 is chosen as a radioisotope heat source and a thermal reductive layer is also used to obtain precise thermionic emissions. The self-sufficiency principle is applied by simultaneously heating up the emitting material with the radioisotope decay heat and by powering the different valves of the plasma rocket engine with the same radioisotope decay heat using a radioisotope thermoelectric generator. This rocket engine is then benchmarked against a 1 N hydrazine thruster configuration operated on one of the Pleiades-HR-1 constellation spacecraft. A maximal specific impulse and power saving of respectively 529 s and 32% are achieved with helium as propellant.Its advantages are its power saving capability, high specific impulses and simultaneous ease of storage and restart. It can however be extremely voluminous and potentially hazardous. The Kabila rocket is found to bring great benefits to the existing spacecraft and further research should optimize its geometric characteristics and investigate the physical principals of its operation.     

自主可控技术在试验任务领域的应用研究

试验信息系统是航天发射和科研试验任务的关键支撑,需要走自主可控的道路。基于此,首先说明了试验信息系统的自主可控现状,并从多方面分析了面临的主要安全威胁。基于自主可控技术发展水平及发展现状分析了推进自主可控的可行性,再分别从网络设备、计算机设备、存储设备、操作系统、数据库等基础软件、安全防护设备、核心器件等方面提出了自主可控技术应用策略,并相应提出自主可控的应用软件研制策略。最后针对推进自主可控的风险进行了深入分析,提出了具体的应对措施。经过多个典型系统应用表明,基于国产品牌硬件设备和自主基础软件平台,经过一定的适配和系统定制,能够满足试验任务强实时、高可靠性要求。     

Use of MOBITEX wireless wide area networks as a solution toland-based positioning and navigation

The emergence of land-based positioning and navigation systems is the direct result of advancements in technologies relating to geographic information, wireless data communication, and navigation. The increasing demand for these systems has stimulated their rapid development. This paper identifies the wide variety of land-based positioning and navigation systems and classifies them into five groups. The basic system elements that are required in all land-based positioning and navigation systems are also discussed. A proposed system infrastructure that supports the five types of land-based positioning and navigation systems is described. The specific technologies integrated in this proposed infrastructure include the Global Positioning System (GPS), differential GPS, and the MOBITEX wireless wide area packet data networks. Real-time wireless mobile data communication is a key component of any land-based positioning and navigation system. Finally, the evaluation criteria necessary for field testing a pilot land-based positioning and navigation system are presented. This pilot system is used to determine the feasibility and effectiveness of the proposed system design     

航空生产计划系统的模糊仿真

 飞机制造过程通常比较复杂，仿真模型可以帮助工程技术人员理解这一复杂的过程和找出系统中的瓶颈。用高级仿真技术和模糊方法于某航空企业的生产计划系统，建立模糊仿真模型和软件系统，研究生产计划的可行性，以满足生产管理的需要。     

基于资源共享的分布式机载软件测试系统设计

随着装备软件系统的发展,越来越多的硬件功能软件化,装备软件的发展朝着高综合、高集成、一体化的趋势发展。目前航空航天装备软件中,嵌入式软件占据主导地位,相较通用计算机软件,嵌入式软件的测试具有面向特定应用,有实时操作系统支持,运行芯片和平台较为固定,并且需要特定的数字总线资源进行数据注入等特点。尤其对于复杂的,高度综合化模块架构的嵌入式软件系统软件测试,对于测试和验证系统的要求也越来越高,数据采集、数据记录、数据激励、数据监控、数据分析等各种测试和验证系统的需求也使得综合化软件测试验证系统结构越来越复杂,基于分布式架构的软件测试系统已经成为必然趋势。结合嵌入式综合化软件测试系统的功能要求以及测试系统的特点,提出了一种基于对等架构下的分布式测试系统设计,该设计不仅能够满足嵌入式软件运行平台规模的扩展,也能够在分布式架构下实现软件运行平台内部资源的共享。     

离子推进器和流量控制单元

使用电动电源线确保使用电力,它等于几十千瓦。 建议它应该高达10000秒。 Keldysh研究中心（KeRC）正在开发推进系统。 35千瓦离子推进器和FCU-500流量控制单元。 IT-500和FCU-500的2000小时寿命测试是 离子推进器大部分运行2018小时,使用40千克氙气。 本文还介绍了磁场和离子光学的改进以及石墨网格的发展状况。     

大功率离子推力器和流动控制单元验证现状 及其2000小时寿命试验

为了发展基于电推进的大功率空间运输系统,需要开发和验证功率达数十千瓦的电推进系统,深空任务电推进系统优化的比冲要求高达10⁵s。凯尔迪什研究中心（KeRC）正在开发这样的电推进部件。本文概述了 35kW离子推力器 IT-500及其流动单元FCU-500的验证现状。作为其验证的一部分,完成了IT-500 和 FCU-500的2000h寿命试验。其中,离子推力器大部分验证条件是：输入功率17.8kW,使用了40kg氙,2018h寿命试验。本文介绍了磁场和离子光学以及石墨格栅开发现状。     

Telemetry Transmitters Using Solid-State Wideband Microwave Voltage-Controlled Oscillators

A practical approach for meeting the immediate and future needs of communication systems that require very wideband transmitters capable of operating in the S-, C-, and X-band frequency ranges is described. Included are: 1) a review of the basic studies conducted to determine the most practical transmitter approach for wideband applications; 2) a discussion of a prototype 10-watt frequency-modulated transmitter developed to demonstrate the feasibility of a wideband system; and 3) a review of the preliminary computer analyses and empirical results obtained on the development of a unit capable of wide deviation with reasonable linearity at baseband frequencies up to 10 Megahertz.     

Analysis of Local Slopes at the InSight Landing Site on Mars

To evaluate the topography of the surface within the InSight candidate landing ellipses, we generated Digital Terrain Models (DTMs) at lander scales and those appropriate for entry, descent, and landing simulations, along with orthoimages of both images in each stereopair, and adirectional slope images. These products were used to assess the distribution of slopes for each candidate ellipse and terrain type in the landing site region, paying particular attention to how these slopes impact InSight landing and engineering safety, and results are reported here. Overall, this region has extremely low slopes at 1-meter baseline scales and meets the safety constraints of the InSight lander. The majority of the landing ellipse has a mean slope at 1-meter baselines of 3.2°. In addition, a mosaic of HRSC, CTX, and HiRISE DTMs within the final landing ellipse (ellipse 9) was generated to support entry, descent, and landing simulations and evaluations. Several methods were tested to generate this mosaic and the NASA Ames Stereo Pipeline program dem_mosaic produced the best results. For the HRSC-CTX-HiRISE DTM mosaic, more than 99 % of the mosaic has slopes less than 15°, and the introduction of artificially high slopes along image seams was minimized.     

Reconfigurable COTS test systems

Automatic Test Equipment (ATE) systems are used to qualify, accept, and troubleshoot electronic products. ATE systems may be in the form of large general-purpose systems that can test a wide variety of products or the more commonly used custom, turnkey systems that are designed for specific test application(s) and requirements. Turnkey ATE systems are labor-intensive; as a result, even a relatively simple turnkey tester is costly and may take months (or even years) to develop, integrate, and deploy. The main reason for this aspect of turnkey ATE systems is that even though the instrumentation may be off-the-shelf components, most everything else is custom and requires design, development, extensive debug and integration. Time and again, systems integrators have tried to find a solution that would combine the cost effectiveness of COTS systems with the flexibility of custom ATE. This paper suggests a solution to this problem and that it is feasible to combine COTS testers with custom requirements. This solution, called CreATE, provides a flexible architecture using COTS components (including instruments, cabling and interfacing products)     

Multi-channel data structure and real-time compression algorithm research

The development of space telemetry technology has brought forward the need for large capacity memory of any solid-state recorder; data compression therefore, becomes more and more important. The compression feasibility and potentiality of telemetry data are examined by analyzing the statistical characteristics of actual telemetry data recovered from recorders. Aiming at the disadvantage of present data formats in data compression for multi-channel telemetry data acquisition systems, this introduces a data packet structure, and a real-time compression algorithm for low complex hardware design. The principles and implementations of data package compression are described. Simulation results show that this technology can meet the requirements of multi-channel real-time data compression with a high compression ratio and a fast compression speed, which possesses great application value.     

Engine-driven generators for deep space probes

Summarizes important developments relating to power for deep space missions. The important alternatives to thermocouples for converting radioisotope heat into electric power are Stirling engines, alkali-metal thermal-to-electric converters (AMTEC), thermionic converters, and thermo-photovoltaic converters. The operating principles and limitations of these converters are described.     

Integrated automatic vehicle location systems

The state-of-the-art transportation management system integrates automatic vehicle location, in-vehicle systems, customer information networks, and management information systems. As advanced technologies are integrated into transportation systems, the transit system becomes more efficient and reliable, which, in turn, makes it more attractive to users. The greatest benefit will not be realized until all of these technologies are integrated. Transit agencies and system integrators who take a total systems approach to the integration of advanced technologies will have a competitive advantage. They will provide services which provide the greatest utility to prospective users, riders, and the transit agency at the lowest cost