Steering the station back on course

Rising costs of the International Space Station prompted NASA to convene a panel of experts to assess the quality of ISS cost estimates and review program assumptions and requirements. The panel concluded that NASA was unable to accurately predict ISS costs or to support requests for increased funding for the ISS through 2006 and should maintain a U.S. core complete program with three-person crews with 6-month stays on the ISS. International response to the panel report was negative with space agencies from Japan, Russia, Canada, and Europe taking issue with the expected impact on ISS construction and use.     

PAVE PACE: system avionics for the 21st century

The PAVE PACE Initiative has been established to validate system avionics concepts for advanced military aircraft. The author presents the rationale of why the advanced architecture established by the PAVE PILLAR program should be continued under PAVE PACE to achieve: practical and affordable airborne versions of modular parallel processing network architectures for many applications currently beyond real-time implementation, readily available avionics for use in all avionics and, greatly improved techniques to reduce the cost of software development and support. An approach to the overall design structure for future avionics is also presented that entails: the use of CAD (computer-aided design) tools to assist in the development of system, hardware and software requirements, the use of replicated hardware modules (some at the wafer level), the use of reuseable software modules and the use of CAD tools to tailor hardware/software modules for specific application requirements. Continued use of the PAVE PILLAR high-speed data bus and operating system is recommended as the means to integrate and control the data input and output of physically and functionally separate parallel networks     

Mechanical engineering's role in multi-disciplinary radar design

Successful execution of a program and full satisfaction of the customer's requirements is a challenge for any contractor. Raytheon Company responds to this challenge by following a proven program execution methodology. The methodology includes all program aspects from financial planning to engineering to validation and test. This discusses the engineering team and the role of the mechanical engineer. A radar system is ultimately an assembly of advanced electronics and software. However, the design, fabrication, assembly, integration, and test Of this complex system requires a coherent multi-disciplinary approach. Raytheon, like many contractors, chooses to assemble an integrated product team (IPT) including all engineering disciplines. Mechanical engineering is integral to satisfying performance requirements, performing preliminary and detailed design, transition of the design to manufacturing, and implementation of the hardware in the field. During definition, mechanical engineering assists fundamental architecture development, conceptual design, and requirements development which precludes issues that are sometimes ignored to the detriment of many programs. These design issues include environmental protection, structural stiffness to meet deflection requirements, cooling system capacity to properly remove dissipated heat, manufacturabilit3' to control cost, maintainability to enable repair in the field, and transportability. Recognizing and trading off these issues early greatly increases the Probability Of satisfying customer objectives. This discusses the approach Raytheon is taking to ensure an overall multi-disciplinary solution to our design challenges from the perspective of the mechanical engineer.     

AEDC's facility computer enhancement project

The Arnold Engineering Development Center (AEDC) constitutes the largest collection of test cells, wind tunnels, altitude chambers, and ballistic ranges in the free world. AEDC is presently in the midst of an aggressive investment program to decrease the cost of aerospace testing by improving test efficiency and preparing for test requirements projected through 1993. To achieve the desired gains in testing, a multimillion dollar program has been initiated to upgrade data-processing capabilities. This effort, the Facility Computer Enhancement Program (FCEP), replaces the existing facility with new and more powerful computers and state-of-the-art communications networks that link all test processors at AEDC. Tradeoffs and technical considerations during the first year of the program and the design of the new system are discussed. Capabilities that support test objectives at the completion of the project are presented     

The International Space Station: a question of federal funding andpolicy implications

A summary form is given of the author's full paper (ibid. vol. 33, p. 7, 1998). The ISS program is a huge investment by the U.S. government. It is estimated by NASA that the program will cost the American public more than $70 billion over a period of 30 years. Since the scientific impact of this program is relatively unknown (and uncertain), the question that policy makers will have to struggle with is whether the federal government should continue to fund the program, or to pull out from the program altogether, thus saving American taxpayers close to $30 billion. Although funding is a major concern, since the inclusion of Russia in the program, the ISS has also become a foreign policy tool. Therefore, additional questions about policy implications of the ISS program need to be addressed     

Modular Stores Management System

Advanced Military aircraft operational requirements demand an ever increasing variety and quantity of Stores, coupled with continuous improvement in mission success, safety of operation, aircrew and groundcrew workload, interoperability and ground support facilities. Until now these ever more demanding requirements have been met by costly customized stores management system designs. GEC Avionics has surveyed the potential SMS requirements of a comprehensive range of aircraft and weapon types, in order to define a universal SMS design concept based on system availability, integrity and reliability, operational functions, peripheral interfaces and maintenance/human factors. This advanced concept not only includes provision for all existing weapon types but also has growth potential for the evolving MIL-STD-1760 weapon interfaces. System interface requirements have been rationalized in order to achieve a Modular Stores Management System (MSMS) design based on major factors such as cost, mission requirements and customer specifications. The key work for a successful MSMS design is flexibility and GEC Avionics has evolved a set of standard modules which can be packaged to satisfy specific customer needs. Typically, the standard modules provide over 80% of the hardware in every Stores Management application. The MSM concept features much reduced development costs and timescales, commonality between aircraft types minimizing parts inventory, VLSI technology providing high reliability and a common product support and maintenance philosophy. The MSM design offers a highly cost effective low risk concept for meeting the needs of modernization and new aircraft programs.     

Power management and distribution system for a more-electricaircraft (MADMEL)

A five-phase Power Management and Distribution System for a More-Electric Aircraft (MADMEL) program was awarded by the Air Force to Northrop/Grumman Military Aircraft Division in September 1991. The objective of the program is to design, develop, and demonstrate an advanced electrical power generation and distribution system for a More-Electric Aircraft (MEA). The MEA emphasizes the use of electrical power in place of hydraulics, pneumatic, and mechanical power to optimize the performance and life cycle cost of the aircraft. This paper presents an overview of the MADMEL program and a top-level summary of the program results, development and test of major components to date. In Phase I and Phase II studies, the electrical load requirements were established and the electrical power system architecture was defined for both near-term (NT-year 1996) and far-term (FT-year 2003) MEA application. The detailed design and specification for the Electrical Power System (EPS), its interface with the Vehicle Management System, and the test set-up were developed under Phase III. Phase IV, fabrication and testing of the subsystem level hardware, has been completed. Overall system level integration and testing, Phase V, is scheduled to be completed by September 1999     

TALONS 95 GHz radar sensor for autonomous landing guidance

Ground tests of the TALONS (tactical avionics for low-level navigation and strike) 95-GHz radar sensor are reported. Radar backscatter data were taken for a runway/taxiway system at realistic depression angles in various weather conditions to determine the effects of precipitation and fog. The data were analyzed and utilized to produce radar imagery. Radar cross-sections of several tactical targets were also measured. It was found that the conditions encountered during the test program were virtually transparent to 95-GHz energy at the detection ranges required for landing guidance     

固体火箭发动机试验综合软件系统设计

介绍一种固体火箭发动机试验用综合软件系统。该软件系统除具有标定、数据采集、试验数据分析处理功能外,还具有固体火箭发动机性能预估、参数辨识,以及试验数据库管理功能。该系统能自动快捷地分析处理各类试验数据,有效提高了试验效率。      

优化方法在空调系统设计中的应用

本文以涡轮风扇式冷却系统对歼击机座舱进行空调为例,以系统所引起的起飞燃油重量代偿损失为目标函数,保证驾驶员舒适的条件,对优选飞机空调系统参数的方法进行了探讨。计算表明文内所建立的数学模型是合理的,所采用的罚函数法及单纯形加速法是适宜的。     

Joint STARS phased array radar antenna

The Joint STARS phased array radar system is capable of performing long range airborne surveillance and was used during the Persian Gulf war on two E8-A aircraft to fly many around-the-clock missions to monitor the Kuwait and Iraq battlefield from a safe distance behind the front lines. This paper is a follow-on to previous publications on the subject of the Joint STARS antenna and deals mainly with mission performance and technical aspects not previously covered. Radar data of troop movements and armament installations are presented, a brief review of the antenna design is given, followed by technical discussions concerning the three-port interferometry, gain and sidelobe design approach, cost control, range test implementation and future improvements     

VXI总线模块自动测试系统设计

针对某计算机模块的测试要求,组建及开发了基于VXI总线系统的某计算机模块测试设备和其测试系统软件。该测试设备的研制对实现某计算机模块大批量生产的快速检测,及对返修模块的故障定位提供了有利的工具,同时由于VXI测试平台的开放性、可扩展性,用户根据自己需要可开发不同的系统测试软件,提高了测试设备的通用性。     

Aircraft VSCF generator expert system

VSCF (variable-speed constant-frequency) electrical systems are designed using standard modules to reduce the manufacturing cost and improve the product quality and services. An expert system that automatically configures the modules required for a particular application is described. It is a rule-based synthesis system with a domain that encompasses the matrix of standard modules. The module functions include electrical generation, conversion, the control. All the modules must be placed in a proper package to fit the space available inside the particular airplane. The configuration system is built by using a rule-based expert system development tool, OPS5, in a VAX 11/750 computer. It has the domain-specific knowledge necessary to configure the generators embedded in its rulebased and exhibits expertise to place the modules in the proper arrangement based on customer specifications and design criteria. The system can also help the engineers and salespersons to determine the configuration at quotation time and to point out any new design which is required     

面向综合CNI 系统的双机热备份切换方案设计

本文针对综合CNI 系统主备切换功能的实现，提出了一种基于表决算法的双机热备份主从模式的设 计方案，从设计思路、设计原则以及冗余备份、主备切换的故障故障检测等方面进行详细分析，对上电确定主 备流程、主切备流程以及备切主流程进行详细设计，通过方案验证，在不增加硬件基础上，能够快速无缝地将 相应的功能控制切换至备模块，提高了整个综合CNI 系统的可靠性，保障系统不间断运行。     

A space-fed phased array for surveillance from space

A space-fed radar antenna called a venetian blind is proposed for all-weather wide-area surveillance from space. Radar requirements for tasked and untasked operation are discussed, and the process of selecting the venetian blind concept, which can support both, is described. In its untasked form (essentially a space-fed passive lens), it achieves off-axis squint angles of many beamwidths with negligible performance degradation. It is inherently insensitive to mechanical distortion and is a first step in the evolution to the more complex tasked system antenna. The antenna lens consists of easily manufactured slats with microstrip dipole radiating elements and matching networks on a dielectric substrate. Phase control is achieved with low-loss delay lines in the passive lens or active transmit/receive modules if electronic scan is desired     

MEMS Electronically Steerable Antennas for Fire Control Radars

Large apertures are of great benefit to applications that are prime powered limited as is found on aerostat and other airborne platforms. Electronically scanned array antennas are often proposed for these applications. However, increasing the aperture area with conventional array technology is met with prohibitive cost, weight, and prime power increases because of the dense spacing of phase shifters and/or active T/R modules. This discusses the recent development of RF MEMS (Microelectromechanical System) switch technology and the use of these switches in a Radanttrade lens configuration for arrays of approximately 10 m² at X-band. A proof-of-concept 0.4 m² MEMS Electronically Steerable Antenna (ESA) containing 25,000 MEMS switches has been successfully designed, fabricated, and tested. The 0.4 m² MEMS ESA was then integrated with an AN/APG-67 radar system to form the MEMS Demonstration Radar System. The MEMS Demonstration Radar System successfully detected both airborne and ground moving targets during a series of extensive radar demonstrations. This is believed to be the first large scale employment of MEMS switches in a scanning antenna and radar system. The low-cost, lightweight, and low power technology demonstrated can enable weight and power constrained platforms with electronic steering.     

Re-hosting test program sets effectively and affordably [formilitary ATE application]

This paper describes an innovative process for re-hosting test program sets from an existing tester for which they were originally prepared to operate on another tester. The process greatly reduces the time and cost usually required for offloading a test program set while retaining most of the original design and interface hardware     

The THEMIS Magnetic Cleanliness Program

The five identical THEMIS Spacecraft, launched in February 2007, carry two magnetometers on each probe, one DC fluxgate (FGM) and one AC search coil (SCM). Due to the small size of the THEMIS probes, and the short length of the magnetometer booms, magnetic cleanliness was a particularly complex task for this medium sized mission. The requirements leveled on the spacecraft and instrument design required a detailed approach, but one that did not hamper the development of the probes during their short design, production and testing phase. In this paper we describe the magnetic cleanliness program’s requirements, design guidelines, program implementation, mission integration and test philosophy and present test results, and mission on-orbit performance.     

基于双ARM系统的MIMU航姿测量系统的 研究及实现

针对小型无人机武器平台对航姿系统小型化、低成本、集成化的设计要求,提出了一种基于双ARM系统的MIMU航姿测量系统,实现了单板集成所有惯性测量、初始对准、惯性导航、组合导航,以及航姿测量等功能.通过车载导航试验及飞行试验考核,该系统可以满足用户应用需求.