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Temperature sensors and heaters belong in the diagnostics subsystem of the LISA Technology Package (LTP) on board LISA Pathfinder, the technology demonstrator for LISA. A number of these diagnostics items are placed at short distances from the LTP proof masses and are negative temperature coefficient (NTC) thermistors. By design, these devices have tiny amounts of ferromagnetic materials, which therefore constitute a potential source of disturbance to the performance of the LTP. In this paper we report on detailed magnetic characterization of the NTCs and use the data to evaluate their impact on the acceleration noise budget of the LTP. The effect is seen to be small if the NTCs are submitted to a demagnetization process before they are attached. Remagnetization is unlikely, as rather strong fields (approximately millitesla) are required to produce enough NTC magnetic polarization. [ABSTRACT FROM AUTHOR]

The SuperNova Acceleration Probe (SNAP) instrument is being designed to collect image and spectroscopic data for the study of dark energy in the universe. In this paper, we describe a distributed architecture for the data acquisition system which interfaces to visible light and infrared imaging detectors. The architecture includes the use of NAND flash memory for the storage of exposures in a file system. Also described is an FPGA-based lossless data compression algorithm with a configurable pre-scaler based on a novel square root data compression method to improve compression performance. The required interactions of the distributed elements with an instrument control unit will be described as well. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a dual-stage control system design method for the flexible spacecraft attitude maneuvering control by use of on–off thrusters and active vibration control by input shaper. In this design approach, attitude control system and vibration suppression were designed separately using lower order model. As a stepping stone, an integral variable structure controller with the assumption of knowing the upper bounds of the mismatched lumped perturbation has been designed which ensures exponential convergence of attitude angle and angular velocity in the presence of bounded uncertainty/disturbances. To reconstruct estimates of the system states for use in a full information variable structure control law, an asymptotic variable structure observer is also employed. In addition, the thruster output is modulated in pulse-width pulse-frequency so that the output profile is similar to the continuous control histories. For actively suppressing the induced vibration, the input shaping technique is used to modify the existing command so that less vibration will be caused by the command itself, which only requires information about the vibration frequency and damping of the closed-loop system. The rationale behind this hybrid control scheme is that the integral variable structure controller can achieve good precision pointing, even in the presence of uncertainties/disturbances, whereas the shaped input attenuator is applied to actively suppress the undesirable vibrations excited by the rapid maneuvers. Simulation results for the spacecraft model show precise attitude control and vibration suppression. [Copyright &y& Elsevier]

A low-volume low-mass low-power ultra-high-frequency radio transceiver for future planetary missions is described. The project targets a volume of less than 10 cm⊃3, mass of less than 50 grams, and power consumption of 50 mW on receive and 100 mW, 300 mW, or 3 W on transmit (for 10 mW, 100 mW, and 1 W output options). The transmitter design supports convolutionally coded binary phase-shift keying (BPSK), RC-BPSK, and quadrature phase-shift keying transmission from 1 to 256 kbps. Command/control instructions can be received at 2 or 8 kbps, with a sensitivity of better than -120 dBm. In addition to its low volume/mass/ power features, temperature compensation to -100 °C and radiation tolerance to 100 krad allow operation outside of thermally controlled, shielded enclosures, further reducing the mass and complexity of exploration vehicles. The design is described in a top-down format, beginning with system requirements and proceeding through digital modem algorithm development, discussion of the silicon-on-sapphire CMOS process used and elaboration of key blocks in the radio-frequency (RF) integrated circuit design. Techniques to address coupling between high-sensitivity RF and on-chip digital circuits are also presented, and test results are given for prototypes of all major functions. Although designed for the Martian environment, the transceiver is expected to be useful in other proximity links where a small low-power radio compatible with Prox-1 space-link protocols is desired. [ABSTRACT FROM AUTHOR]

Abstract: Satellite systems provide the most efficient and possibly the only means of achieving two-way global communications with mobile systems (ships, aircraft, and vehicular traffic). To date, such systems have used only circular orbits, either GEO or LEO. Medium altitude elliptical constellations, on the other hand, can provide an efficient and affordable alternative to these architectures. Users also benefit from their very high average and minimum elevation angles, resulting in minimum signal attenuation. Cobra Teardrop is unique in that it employs time synchronized 8-h left- and right-leaning elliptical orbits giving mid-latitude observers the illusion of viewing a single satellite continuously orbiting almost directly overhead! In reality, observers see six different satellites per day, for 4h each (while in their active duty cycles). By design, Teardrop satellites are physically in very close proximity at the handover points. This favorable geometry can be utilized to achieve a seamless handover from one satellite to the other (not requiring any electronic buffering). Handover is accomplished at the precise instant that the total path lengths from the transmitting station through both satellites to the receiving station are exactly equal. In these improved Cobra Teardrop arrays, an order of magnitude increase in global communications capacity (equivalent GEO slots) can be realized over earlier Basic Cobra systems. For decades into the future, these new orbital systems could satisfy a widely expanding range of commercial, government, and military high data rate communication requirements. These would include, but not be limited to, satellite cellular, air traffic control, meteorological, and combat net radio systems. With these arrays, a much larger number of system operators could be supported, without mutual electronic interference, than would ever be possible with circular orbits. [Copyright &y& Elsevier]

New dielectric materials have been introduced for printed circuit board applications, such as Thermount and polyimide with the aim to match the requirements for high speed and high density of electronic devices that are planned for new spacecraft electronic boards. Before these newer substrate can fully replace the well-known space-approved material epoxy FR-4, it is necessary to investigate more deeply their electrical and mechanical properties. The scope of this study is to report quantitative characterization of the surface resistivity for the different material samples under various testing conditions that include relative humidity, temperature, solder flux contamination, and corona discharge. The surface resistivity results are reported for sets of samples measured under a combination of testing conditions. [ABSTRACT FROM PUBLISHER]

To evaluate the characteristics of commercial memory devices for space use, the Japan Aerospace Exploration Agency (JAXA) launched a Solid State Recorder (SSR) on the Mission Demonstration test Satellite-1 (MDS-1 or ‘Tsubasa’) into geo-stationary transfer orbit (GTO) in February 2002. Passing through the radiation belt exposed the MDS-1 to severe radiation environment in every orbit. This flight experiment allowed the observation of Single-Event Upsets (SEU) and Total Ionizing Dose (TID) effect on a large number of stacked 64 Mbit Dynamic Random Access Memories (DRAM). As a result, the actual SEU rates could be calculated, and the capabilities of two types of on-the-fly Error Detection and Correction (EDAC) mechanisms were confirmed. This paper presents the results of the space experiment of SSR, focusing especially on SEU analysis. [ABSTRACT FROM AUTHOR]

The purpose of the Space Shuttle cockpit avionics upgrade project was to reduce crew workload and improve situational awareness. The upgrade was to augment the Shuttle avionics system with new hardware and software. An early version of this system was used to gather human factor statistics in the Space Shuttle motion simulator of the Johnson Space Center for one month by multiple teams of astronauts. The results were compiled by NASA Ames Research Center and it was determined that the system provided a better than expected increase in situational awareness and reduction in crew workload. Even with all of the benefits of the system, NASA cancelled the project toward the end of the development cycle. A major success of this project was the validation of the hardware architecture and software design. This was significant because the project incorporated new technology and approaches for the development of human rated space software. The major technological advances were the use of reflective memory concepts for data acquisition and the incorporation of commercial-off-the-shelf (COTS) products in a human rated space avionics system. The infused COTS products included a real-time operating system, a resident linker and loader, a display generation tool set, and a network data manager. Some of the successful design concepts were the engineering of identical outputs in multiple avionics boxes using an event driven approach and inter-computer communication, a reconfigurable data acquisition engine, the use of dynamic linking at runtime, and the use of a dynamic bus bandwidth allocation algorithm. Other significant experiences captured were the use of prototyping to reduce risk, and the correct balance between object oriented and functional based programming [ABSTRACT FROM PUBLISHER]

Abstract: Space exploration missions require electronics capable of efficient and reliable operation at low temperatures. Presently, spacecraft on-board electronics are maintained at approximately 20°C through the use of radioisotopes. Cryogenic electronics would enhance efficiency of space systems, improve reliability, and simplify their design. A Low Temperature Electronics Program at the NASA Glenn Research Center focuses on research and development of electronics suitable for space exploration missions. The effects of cryogenic temperature and thermal cycling are being investigated for commercial-off-the-shelf components as well as for components specially developed for low temperature operation. An overview of this program along with selected experimental data is presented in this paper. [Copyright &y& Elsevier]

Advances in electronics over the past decade have produced major improvements in the power and flexibility of computer systems. Unfortunately current avionics systems for space applications typically have not leveraged these COTS advantages. A decade ago, the state-of-the-art for avionics systems made a step change to the Integrated Modular Avionics (IMA) used in the Boeing 777. This next generation avionics architecture is not based upon traditional Byzantine redundancy structures, but on a truth-based scheme where each element knows when an internal failure occurs and removes itself from the system. IMA utilizes a lock-step microprocessor design that communicates to a COTS Backplane for input/output, and to a Virtual Backplane™ (a reliable high-speed serial bus) for intra-system communication. The system functions are implemented using a time and space partitioned operating system. The entire system provides the simplicity of a simplex system, implements the highest level of reliability providing complete flexibility to reconfigure both software applications and hardware interfaces, allows for rapid prototyping using low-cost COTS hardware, and is easily expandable beyond the initial point implementation. As the only 5th generation avionics architecture, the concepts incorporated into Honeywell's IMA are ideally suited to be the backbone of the next generation Space Exploration Program avionics architectures. [ABSTRACT FROM PUBLISHER]

Models and methods in use for quantitative estimates of the occurrence of single event upsets in microchips of orbiting spacecraft are considered. A calculation and experimental technique for determining the rate of these effects is described, taking into account spatial and temporal distributions of the fluxes of high-energy particles in the space and their penetration through protective shields. Examples of its application for the orbit of the International Space Station are presented. [ABSTRACT FROM AUTHOR]

Problems are discussed and recommendations concerning aerodynamic support of design works of spacecrafts carrying soiling-sensitive optical-electronic and other on-board equipment are given. Study of mass transfer processes about optical telescope of spacecraft "Sich-2" at the design stage is carded out. Analysis of aerodynamical soilings, which affected "Ocean-O" spacecraft during its exploitation, was made. [ABSTRACT FROM AUTHOR]

The optical spectrograph and infrared imager system (OSIRIS) on board the Odin spacecraft is designed to retrieve altitude profiles of terrestrial atmospheric minor species by observing limb-radiance profiles. The grating optical spectrograph (OS) obtains spectra of scattered sunlight over the range 280–800 nm with a spectral resolution of approximately 1 nm. The Odin spacecraft performs a repetitive vertical limb scan to sweep the OS 1 km vertical field of view over selected altitude ranges from approximately 10 to 100 km. The terrestrial absorption features that are superimposed on the scattered solar spectrum are monitored to derive the minor species altitude profiles. The spectrograph also detects the airglow, which can be used to study the mesosphere and lower thermosphere. The other part of OSIRIS is a three-channel infrared imager (IRI) that uses linear array detectors to image the vertical limb radiance over an altitude range of approximately 100 km. The IRI observes both scattered sunlight and the airglow emissions from the oxygen infrared atmospheric band at 1.27 µm and the OH (3-1) Meinel band at 1.53 µm. A tomographic inversion technique is used with a series of these vertical images to derive the two-dimensional distribution of the emissions within the orbit plane. PACS Nos.: 07.05.Pj, 07.60.Dq, 07.60.Rd, 07.87, 94.10.Dy, 94.10.Fa, 94.10.Gb, 94.10.Rk [ABSTRACT FROM AUTHOR]

The spectrometer-telescope “STEP-F” is intended for detecting high-energy charged particle fluxes in near-Earth space. It has been developed to study solar cosmic rays and dynamics of the Earth''s radiation belts onboard the Russian spacecraft ≪Coronas-Photon≫. The results of simulations by the CERN GEANT4.2 Code under OS LINUX Red Hat 6.2 for some types of particles, which will be detected by the “STEP-F” instrument, are presented. The visualization of primary and secondary particle tracks in each detector of the telescope has allowed us to verify the energy ranges of the recorded particles and to ascertain the possibility to determine the direction of incidence of primary electrons. The detectors have been tested in a high-energy ion cyclotron accelerator at the Institute of Physical and Chemical Research (RIKEN, Japan) in order to determine the response of each of the detectors to primary α-particle and hydrogen ion H2 beams. The experimental data obtained are in good agreement with the results of Monte-Carlo simulations. The basic parameters of the “STEP-F” instrument, such as the energy range of recorded electrons, protons and α-particles, the geometric factor, the field of view and the angular resolution, are presented. [Copyright &y& Elsevier]

This article represents the research results of the television space surveillance system, or, in other words, the optical surveillance system. The purpose of the work is the design of a specialized optical surveillance system, stabilization and surveillance equipment, and a television unit. The system's simplified structural and functional scheme is described, as well as its justification and operation principle. The application prospects are estimated. [ABSTRACT FROM PUBLISHER]

Presents a review of some of the progress that is being made in this exciting area of nanosciences and the potential impacts on the future of aerospace systems and capabilities. [ABSTRACT FROM PUBLISHER]

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 37th 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. [ABSTRACT FROM PUBLISHER]

The first complete 70 GHz back end module (BEM) of the coming Planck satellite is described. It includes an H-plane waveguide band pass filter, an InP HEMT amplifier, a diode detector made on 0.1 mm alumina substrate, and video amplifiers. RF parts are designed, manufactured, and measured individually and then the complete BEM is tested. Stringent requirements are set through the mechanical layout of the entire functional unit. Most specifications have already been met with the exception of conversion loss in band ripple which must be further reduced. [ABSTRACT FROM PUBLISHER]

At IECEC 2001, this team presented a paper on the new stretched lens array (SLA), including its evolution from the successful SCARLET array on the NASA/JPL Deep Space 1 spacecraft. Since that conference, the SLA team has made significant advances in SLA technology, including component-level improvements, array-level optimization, space environment exposure testing, and prototype hardware fabrication and evaluation. This paper describes the evolved version of the SLA, highlighting recent improvements in the lens, solar cell, photovoltaic receiver, rigid panel structure, and complete solar array wing. In addition to excellent durability in the space environment, the near-term SLA will provide outstanding wing-level performance parameters: 180 W/kg specific power; 300 W/m2 power density; 300 V operational voltage; 85% savings in cell area (cm2/W) and cell-related cost ($/W) compared to planar arrays; 9 kW/m3 stowed power at launch. [ABSTRACT FROM PUBLISHER]

It is well known that space radiation, containing energetic particles such as protons and ions, can cause anomalies in digital avionics onboard satellites, spacecraft, and aerial vehicles flying at high altitude. Semiconductor devices embedded in these applications become more sensitive to space radiation as the features shrink in size. One of the adverse effects of space radiation on avionics is a transient error known as single event upset (SEU). Given that it is caused by bit-flips in computer memory, SEU does not result in a damaged device. However, the SEU induced data error propagates through the run-time operational flight program, causing erroneous outputs from a flight-critical computer system. This study was motivated by a need for a cost-effective solution to keep flight-critical computers functioning after SEU occurs. The result of the study presents an approach to recover flight-critical computer systems from SEU induced error by using an identity observer array. The identity observers replicate the state data of the controller in distinct data partitions. The faulty controller can be recovered by replacing data image of the faulty data partition with that of the healthy data partition. The methodology of applying such an approach from the fault tolerant control perspective is presented. The approach is currently being tested via computer simulation [ABSTRACT FROM PUBLISHER]

The following topics are dealt with: engineering systems; hardware; software; environmental hazards; vehicle health; human factors; air traffic control; space systems [ABSTRACT FROM PUBLISHER]

The advent of NASA-JPL's X2000 architecture has brought compactPCI (cPCI) to the forefront as the system bus of choice for space data processing. This paper presents a hybrid architecture allowing the inclusion of new, high performance cPCI modules with heritage VME-based modules. The hybrid system yields a cost-effective, performance optimized processing solution for space [ABSTRACT FROM PUBLISHER]

Safe, reliable, and low cost space-based navigation is being provided with embedded INS/GPS systems such as the space integrated GPS/INS (SIGI). The SIGI is being used for various space vehicle applications such as launch vehicles, orbital vehicles, and re-entry vehicles. This paper describes current space vehicle navigation capabilities. The SIGI is being enhanced to provide additions to these existing capabilities with such items as higher processing and a commercial-off-the-shelf operating system. This will allow hosting of various software applications such as advanced navigation functions, flight control, guidance and vehicle management algorithms. The SIGI can host redundancy management functions by incorporating a cross channel data link card (CCDL) using a high speed firewire bus. The SIGI can then be used as a redundancy management platform which has application to current space vehicle avionics topologies incorporating distributed processing architectures [ABSTRACT FROM PUBLISHER]

The LFI (Low Frequency Instruments) receivers in the coming Planck satellite are of continuous comparison type and use low noise amplifiers based on high electron mobility transistors manufactured from indium phosphide substrate (INP-HEMT-MMIC-LNAs). This article describes the 1/f-noise tests and the associated test system for the 70 GHz demonstrator receiver, which can either use single or dual channel phase switcher methods. The 1/f knee frequency is shown to depend on the calculation method of the r-value. A minimum 1/f knee frequency around 10 mHz has been achieved with full two channel foxtrot and individually adopted r-values for each phase states while a straightforward single phase technology cannot go below 40 mHz [ABSTRACT FROM PUBLISHER]

All aerospace vehicles have the common constraint of limited space for the electronic systems. The challenge has always been how to pack effective electronic systems into the space available. Higher levels of electronic integration can give a competitive advantage; for example, by providing extra channels in a communications satellite thereby increasing revenue to the operator. Today's deep sub-micron manufacturing processes for integrated electronics offer an opportunity for a step change for electronic functionality that can be packaged in a given space. This technology makes possible, for the first time, a true system-on-chip approach to electronic systems, which is already being exploited by the commercial sector in products such as the mobile telephone [ABSTRACT FROM PUBLISHER]

The requirements for this processor were established using the experience of the hardware and software designers in the APL Space Department. The use of commercial hardware and software products, combined with an error- and fault-tolerant architecture, resulted in a low-cost design without adversely affecting overall reliability. The processor's architecture and mechanical design, and hardware and software test and validation methods are described. [ABSTRACT FROM PUBLISHER]

Some recent or near future examples of multidisciplinary systems of systems are illustrated. They include: upgraded Shuttle avionics; Airbus fly-by-wire; integrated modular electronics; electric automobiles; all-electric aircraft; and JointSTARS system [ABSTRACT FROM PUBLISHER]

The following topics are dealt with: orbit determination; attitude control; spacecraft sensors; control torque; and redundancy management [ABSTRACT FROM PUBLISHER]

Electronics and computers have long been associated with aviation, defense and aerospace. Many aerospace advances would have been impossible without digital computers, and digital computers would not have progressed as rapidly without aerospace. In some sense you may thank aerospace for the computer on your desk and Internet in your life. DoD and NASA programs drove computer technology for the first 25 years, but in the 80s the primary thrust transitioned to the commercial sector. Aerospace computation requirements have driven the development of many electronic components such as transistors, ICs and memory technology. Advances in memory technology progressed from delay lines to electrostatic tubes to magnetic cores and now solid-state memory. As the need for number crunching grew, computers transitioned from batch processing, time-sharing, real-time computing, networking to the ubiquitous PC and Internet. How far is it from your hand-held PDA to the nano computer? [ABSTRACT FROM PUBLISHER]

A number of experiments have been made to study the effect that different solder joint designs have on the voltage needed to initiate the onset of corona discharge under low ambient pressures. Wires were joined to both printed circuit board terminations and to electrical feedthroughs. All were constructed from materials known to be suitable for spacecraft. The main factor that determines whether solder joints will be prone to initiate corona discharges or electrical breakdown in a space environment is the actual minimum distance between terminals. Large, rounded solder fillets are desirable, but those containing protrusions or contours around wire strands have little adverse effect. It is shown that it is not always necessary, as is usually required by workmanship specifications related to high voltage connections, for operators to rework solder joints in order to achieve protrusion-free fillets. It would appear from metallurgical analyses of solder joints that it is the tin-rich phase that is sputtered from the fillet's surface during the phenomenon of corona discharge [ABSTRACT FROM PUBLISHER]

The Far Ultraviolet Spectroscopic Explorer (FUSE) satellite was launched on June 24, 1999, on a three-year mission to explore the universe using the technique of high-resolution spectroscopy in the far-ultraviolet spectral region. The FUSE instrument comprises many subsystems, each of which contributes in an essential way to the success of the mission. The instrument system engineer oversees the engineering of all elements in such a complex technical project. In performing system engineering for the FUSE instrument's command, telemetry, data processing and data storage functions, and in leading the engineering efforts for the development of the FUSE instrument on-board computer, the author has learned valuable lessons about the characteristics that are prerequisite to success for a space system engineer. These characteristics fall under various categories of acquired, practical know-how. These categories are described with illustrations drawn from the development of the FUSE instrument. In addition to these practical skills and the concomitant knowledge, the system engineer needs personal integrity, which is the link that connects knowledge with know-how and makes them work together to motivate a team of subsystem engineers. This, too, will be discussed [ABSTRACT FROM PUBLISHER]

Presents information on a study which that assessed the continued increase in importance of commercial programmable devices to spacecraft electronics designers as system requirements increase the trend towards higher performance electronics. Antifuse rupture of heavy ion linear energy transfer (LET); Logic and configuration upset; Radiation test results and analysis.

The primary drivers for space instruments are the environment and survivability, support assets, delivery cost, and lack of accessibility. Survivability deals primarily with environments, such as launch and depressurization, extremes of temperature, high vacuum, radiation, and hypervelocity impacts. The cost to deployment is directly coupled to launch services, which are inherently expensive. These costs are nonlinear functions of the mass and volume of satellite payloads. The “user interfaces” for space-borne instruments are high-cost assets because they include mission operations centers, satellite hacking station(s), and ground networks. All of these issues demand high reliability [ABSTRACT FROM PUBLISHER]

Lockheed Martin Astronautics has developed the Multifunctional Structure (MFS) concept as a new system for spacecraft design that eliminates chassis, cables, connectors and folds the electronics into the walls of the spacecraft. Concurrent engineering will be essential to integrate the electronic, structure, and thermal design. Design methodologies are in work to manage all power, grounding and shielding concerns. The MFS approach offers significant savings in mass and volume and supports the “faster-better-cheaper” philosophy in new spacecraft programs. The technology will be demonstrated as an experiment on the New Millenium Program Deep Space 1 (DS 1) mission [ABSTRACT FROM PUBLISHER]

Presents a project quality management case study for the production of space craft electronic components as part of an overall spacecraft project. Problem description and analysis; Method used in the examination of printed circuit board data; Conclusion.

The high temperature superconductivity space experiment (HTSSE) program, initiated by the Naval Research Laboratory (NRL) in 1988, is described. The HTSSE program focuses high temperature superconductor (HTS) technology applications on space systems. The program phases, goals, and objectives are discussed. The devices developed for the HTSSE-II phase of the program and their suppliers are enumerated. Eight space-qualified components were integrated as a cryogenic experimental payload on DOD's ARGOS spacecraft. The payload was designed and built using a unique NRL/industry partnership and was integrated and space-qualified at NRL. [ABSTRACT FROM AUTHOR]

An experiment designed to ride on the high temperature superconductor space experiment (HTSSE-II) satellite package is described, which monitors the current-voltage characteristics of two high temperature superconductor (HTS) Josephson junctions. The junctions are typical examples of the state-of-the-art at the time of incorporation, and were obtained from two industrial laboratories: TRW and Conductus. Stringent requirements on shielding the devices from RF interference and DC magnetic fields are necessary to ensure that the measurements are meaningful. An additional constraint is imposed by the necessity to minimize flow of heat into the device package. Engineering solutions to these problems, and the resulting performance of the measurement system, are described. The package and associated electronics have been integrated into the flight satellite. [ABSTRACT FROM AUTHOR]

High temperature superconductors (HTS) promise to achieve electrical performance superior to that of conventional electronics. For application in space systems, HTS systems must simultaneously achieve lower power, weight, and volume than conventional electronics, and meet stringent space qualification and reliability requirements. Most effort to date has focused on passive RF/microwave applications. However, incorporation of active microwave components such as amplifiers, mixers, and phase shifters, and on-board high data rate digital signal processing is limited by the power and weight of their spacecraft electronic and support modules. Absence of data on active HTS components will prevent their utilization in space. To validate the feasibility in space of HTS circuits and components based on Josephson junctions, we need to demonstrate HTS circuits and critical supporting technologies, such as space-qualified packaging and interconnects, closed-cycle cryocooling, and interface electronics. This paper describes the packaging, performance, and space test plan of an integrated, space-qualified experimental package consisting of HTS Josephson junction circuits and all the supporting components for NRL's high temperature superconductor space experiment (HTSSE-II). Most of the technical challenges and approaches are equally applicable to passive and active RF/microwave and digital electronic components, and this experiment will provide valuable validation data. [ABSTRACT FROM AUTHOR]

We have constructed a five-bit high temperature superconductive digital instantaneous frequency measurement (DIFM) subsystem capable of determining the frequency of unknown signals over a 500-MHz bandwidth, centered on 4 GHz, with a resolution of 17.8 MHz. The system consists of three parts: a limiting amplifier and filter, a comparator and data processing unit operating at room temperature, and a cryogenic subsystem containing five discriminator modules based on superconductive delay lines, GaAs mixers and power dividers. With a single-tone CW input between -40 dBm and +10 dBm, the frequency quantization boundaries of the subsystem are, on average, 3.1 MHz from their design values. This system was built for the High-Temperature Superconductor Space Experiment, Phase II (HTSSE II). It has passed all required qualification tests for vibration, shock and thermal cycling. The system is currently scheduled for satellite launch in fall 1996. Compared to a conventional system, the superconductive version of the DIFM is considerably smaller and provides enhanced resolution. In addition, the technology employed can be readily extended to a system with additional bits and wider instantaneous bandwidth. The system built demonstrates the potential for system-level applications of high-temperature superconductive electronics in instrumentation, communications, radar, and electronic warfare. [ABSTRACT FROM AUTHOR]

A deep space satellite downconverter receiver was proposed by Jet Propulsion Laboratory (JPL) and NASA Lewis Research Center (LeRC) for the Naval Research Laboratory's (NRL) high temperature superconductivity space experiment, phase-II (HTSSE-II) program. Space qualified low-noise cryogenic downconverter receivers utilizing thin-film high temperature superconducting (HTS) passive circuitry and semiconductor active devices were developed and delivered to NRL. The downconverter consists of an HTS preselect filter, a cryogenic low-noise amplifier; a cryogenic mixer, and a cryogenic oscillator with an HTS resonator. HTS components were inserted as the front-end filter and the local oscillator resonator for their superior 77 K performance over the conventional components. The semiconducting low noise amplifier also benefited from cooling to 77 K. The mixer was designed specifically for cryogenic applications and provided low conversion loss and low power consumption. In addition to an engineering model, two space qualified units (qualification, flight) were built and delivered to NRL. Manufacturing ,integration and test of the space qualified downconverters adhered to the requirements of JPL class-D space instruments and partially to MIL-STD-883D specifications. The qualification unit has /spl sim/50 K system noise temperature which is a factor of three better than a conventional downconverter at room temperature. Commercial applications such as intersatellite links and V-SATS are envisioned to benefit by >3 dB link margin, or a factor of 2 in antenna size, from a future hybrid HTS/semiconducting cryogenic receiver employing new InP based HEMT LNA. In a spread spectrum communication network, the number of users per beam would more than double. [ABSTRACT FROM AUTHOR]

High temperature superconductivity space experiments (HTSSE-I and II) are aimed to demonstrate the feasibility of using high temperature superconductivity (HTS) technology in space systems. In communication satellites, high performance filters and multiplexers represent key microwave components of the payload. Utilization of HTS films in these devices is presented in this paper. The basic HTS resonator/filter structures (including HTSSE-I resonator/filter) suitable for these applications are described. The multiplexer designs and measured results are also described (including the HTSSE-II multiplexer). [ABSTRACT FROM AUTHOR]

The channelized receiver being presented demonstrates the use of high temperature superconductor technology in a microwave system setting where superconductor, microwave-monolithic-integrated-circuit and hybrid-integrated-circuit components are united in one package and cooled to liquid-nitrogen temperatures. The receiver consists of a superconducting X-band four-channel demultiplexer with 100-MHz-wide channels, four commercial monolithically integrated mixers, and four custom-designed hybrid-circuit detectors containing heterostructure ramp diodes. The composite receiver unit has been integrated into the payload of the second-phase NRL high temperature superconductor space experiment (HTSSE-II). Prior to payload assembly, the response characteristics of the receiver were measured as functions of frequency, temperature, and drive levels. The article describes the circuitry, discusses the key issues related to design and implementation, and summarizes the experimental results. [ABSTRACT FROM AUTHOR]

A high temperature superconducting (HTS) four-channel multiplexer and a delay line were fabricated, space qualified and tested as part of the U.S. Navy's High Temperature Superconductivity Space Experiment II (HTSSE-II). The multiplexer had an architecture that included two branch-line hybrids and two identical parallel-coupled line filters per channel. Its operation was centered at 4 GHz, with 50-MHz-wide channels. It was fully integrated, with microstrip interconnections between channels and thin-film load terminations in the out-of-phase port of the output hybrid. The delay line was made up of two cascaded modules for a total delay of 45 ns between 2 and 6 GHz. Both devices were made using 5-cm-diameter LaAlO/sub 3/ wafers coated with epitaxial thin film YBa/sub 2/ Cu/sub 3/O/sub 7/, on both sides in the case of the delay line. Both devices operated at 77 K. [ABSTRACT FROM AUTHOR]

The dc SQUID based RF amplifier (SQA) looks very attractive as an IF amplifier for integration with a SIS mixer and a flux-flow oscillator (FFO) in a fully superconducting submillimeter wave receiver suitable for space applications. Important advantages of the SQA are its low noise, extremely low power consumption, and complete compatibility with the fabrication process currently used for SIS mixers. Single stage amplifiers with a novel signal coupling circuit have been developed and tested in the frequency range 3.6-4.1 GHz. The 1 /spl mu/m/sup 2/ area Nb-AlO/sub x/-Nb junctions shunted by Ti resistors are grouped in a double washer dc SQUID. Two samples with slightly different designs showed the following gain, noise temperature and 3 dB bandwidth: 10.0/spl plusmn/1 dB, 5.0/spl plusmn/1.5 K, 3.86-3.90 GHz, and 6.8/spl plusmn/1 dB, 22/spl plusmn/7 K, 3.89-4.05 GHz, respectively. [ABSTRACT FROM PUBLISHER]

We have optimized a sensitive SQUID measurement system for use in a space flight experiment in the presence of significant interference from other sub-systems and the perturbing effects of EMI and thermal fluctuations. We will describe developments including a sapphire carrier for the SQUID chip, a precision temperature controller for the SQUID, control electronics with high bandwidth and enhanced thermal stability, and special shielding and filtering techniques used to increase EMI resistance. [ABSTRACT FROM PUBLISHER]

A multichannel high‐resolution single‐slope analogue‐to‐digital converter (SS ADC) is presented that automatically compensates for process, voltage and temperature variations, as well as for radiation effects, in order to be used in extreme environmental conditions. The design combines an efficient implementation by using a feedback loop that ensures an inherently monotonic and very accurate ramp generation, with high levels of configurability in terms of resolution and conversion rate, as well as input voltage range. The SS ADC was designed in a standard 0.35 µm CMOS technology. Experimental measurements of the performance and stability against radiation and temperature are presented to verify the proposed approach. [ABSTRACT FROM AUTHOR]