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At least 235 records · Page 13

The Telecommunications and Data Acquisition Report

This publication, one of a series formerly titled The Deep Space Network (DSN) Progress Report, documents DSN progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations. In addition, developments in Earth-based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are reported.

Posner, E. C.↗

Meet the Lightslingers [Slides]

Electromagnetic applications such as Radar or telecommunications use decades-old technology: dipoles, dish/horn antennas, phased arrays.

42 ENGINEERING↗

Space Telecommunications Radio System STRS Cognitive Radio

Radios today are evolving from awareness toward cognition. A software defined radio (SDR) provides the most capability for integrating autonomic decision making ability and allows the incremental evolution toward a cognitive radio. This cognitive radio technology will impact NASA space communications in areas such as spectrum utilization, interoperability, network operations, and radio resource management over a wide range of operating conditions. NASAs cognitive radio will build upon the infrastructure being developed by Space Telecommunication Radio System (STRS) SDR technology. This paper explores the feasibility of inserting cognitive capabilities in the NASA STRS architecture and the interfaces between the cognitive engine and the STRS radio. The STRS architecture defines methods that can inform the cognitive engine about the radio environment so that the cognitive engine can learn autonomously from experience, and take appropriate actions to adapt the radio operating characteristics and optimize performance.

Briones, Janette C.↗

Pointing Error Budget Development and Methodology on the Psyche Project

The Psyche mission was selected by NASA as the 14th mission in the Discovery Program in 2017. The Psyche spacecraft utilizes solar electric propulsion, and will journey to the asteroid (16) Psyche during a 3.5 year trajectory after its planned 2022 launch. The spacecraft instrument suite includes a magnetometer, a multispectral imager, a gamma ray neutron spectrometer, and an X-band radio telecommunications system. It also includes the Deep Space Optical Communication technical demonstration. These instruments along with other spacecraft components require pointing accuracy to meet their scientific and engineering performance requirements. Early on in the project development, the team established a methodology by which pointing accuracy (knowledge and control) is analyzed against the system requirements by means of pointing error budgets and requirement allocations. A margin policy was implemented to ensure the instrument and engineering component pointing accuracy requirements will be met during verification and in flight. Psyche’s pointing management framework defines detailed rationales for the system and subsystem error allocations of the top level pointing accuracy requirements, with sufficient project level pointing margin, and supports end-to-end pointing requirement verification. This paper will present an overview of the Psyche project’s pointing error budget development process, and discuss the rationale behind the methodology. Psyche’s pointing budget methodology integrates best practices and lessons learned from heritage missions, while focusing on the specific needs of the Psyche spacecraft and its science instruments. Key challenges in the pointing error budget development will be reviewed, and a deep dive into two key Psyche pointing budgets are presented. The systems engineering of Psyche’s pointing budget methodology outlined in this paper will serve as a resource for future deep space missions.

Lai, Peter↗

NASA Tech Briefs, November 1995

The contents include: 1) Mission Accomplished; 2) Resource Report: Marshall Space Flight Center; 3) NASA 1995 Software of the Year Award; 4) Microbolometers Based on Epitaxial YBa2Cu3O(sub 7-x) Thin Films; 5) Garnet Random-Access Memory; 6) Fabrication of SNS Weak Links on SOS Substrates; 7) High-Voltage MOSFET Switching Circuit; 8) Asymmetric Switching for a PWM H-Bridge Power Circuit; 9) Better Ohmic Contacts for InP Semiconductor Devices; 10) Low-Bandgap Thermovoltaic Materials and Devices; 11) Digital Frequency-Differencing Circuit; 12) Imaging Magnetometer; 13) Computer-Assisted Monitoring of a Complex System; 14) Buffered Telemetry Demodulator; 15) Compact Multifunction Inspection Head; 16) Optical Detection of Fractures in Ceramic Diaphragms; 17) Eddy-Current Detection of Cracks in Reinforced Carbon/Carbon; 18) Apparent Thermal Conductivity of Multilayer Insulation; 19) Optimizing Misch-Metal Compositions in Metal Hydride Anodes; 20) Device for Sampling Surface Contamination; 21) Probabilistic Failure Assessment for Fatigue; 22) Probabilistic Fatigue and Flaw-Propagation Analysis; 23) Windows Program for Driving the TDU-850 Printer; 24) Subband/Transform MATLAB Functions for Processing Images; 25) Computing Equilibrium Chemical Compositions; 26) Program Processes Thermocouple Readings; 27) ICAN-Second-Generation Integrated Composite Analyzer; 28) Integrated Composite Analyzer with Damping Capabilities; 29) Computing Efficiency of Transfer of Microwave Power; 30) Program Calculates Power Demands of Electronic Designs; 31) Cost-Estimation Program; 32) Program Estimates Areas Required by Electronic Designs; 33) Program to Balance Mapped Turbopump Assemblies; 34) BiblioTech; 35) Controlling Mirror Tilt With a Bimorph Actuator; 36) Burst-Disk Device Simulates Effect of Pyrotechnic Device; 37) Bearing-Mounting Concept Accommodates Thermal Expansion; 38) Parallel-Plate Acoustic Absorbers for Hot Environments; 39) Adjustable-Length Strut Withstands Large Cyclic Loads; 40) Tool Indicates Contact Angles in Bearing Raceways; 41) Gravity Slides With Magnetic Braking; 42) High-Torque, Lightweight, Pneumatically Driven Wrench for Small Spaces; 43) Device for Testing Compatibility of an O-Ring; 44) Magnetic Heat Pump Containing Flow Diverters; 45) Variable-Tilt Helicopter Rotor Mast; 46) "Beach-Ball" Robotic Rovers; 47) Apparatus Would Measure Temperatures of Ball Bearings; 48) Flexible Borescope for Inspecting Ducts; 49) Texturing Copper To Reduce Secondary Emission of Electrons; 50) Automated Laser Cutting in Three Dimensions; 51) Algorithm Helps Monitor Engine Operation; 52) Flexible Revision of Data-Processing Communications; 53) Software for Managing the Use of Land; 54) Thermal Strap Increases Cryocooling Efficiency; 55) Reversible Nut With Engagement Indication; 56) Control Algorithms for Kinematically Redundant Manipulators; 57) Computed Hydrogen-Flow Splits in a Rocket Engine; 58) Pressure and Thermal Modeling of Rocket Launches; 59) Field of View of a Spacecraft Antenna: Analysis and Software; 60) Digital Controller for Laser-Beam-Steering Subsystem; 61) More About Beam-Steering Subsystem for Laser Communication; 62) Digital Controller for Laser-Beam-Steering Subsystem: Part 2; 63) Interface Circuit Board for Space-Shuttle Communications; 64) Automated Planning of Spacecraft Telecommunications; 65) Artifacts of Spectral Analysis of Instrument Readings; 66) Neural-Network Controller for Vibration Suppression; 67) Adaptive Finite-Element Computation in Fracture Mechanics; 68) Attitude Control for the Cassini Spacecraft; 69) Analytical Model for Fluid Dynamics in a Microgravity Environment; 70) Study of Rocket-Engine Joints Bonded by NVCU/NARloy-Z; 71) Improved Silicon Nitride for Advanced Heat Engines; 72) Parameters for Welding Aluminum/Lithium Alloys; 73) Lightweight Composite Intertank Structure; 74) Foil Patches Seal Small Vacuum Leaks; 75) Data Base on Cables and Connectors; 76) Effect of Clock Mode on Radiation Hardnessf an ADC; and 77) Fault-Tolerant Control for a Robotic Inspection System.

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Multiplexing and Demultiplexing Signals for Radiography Application Using the Discrete Fourier Transform

Our goal is to develop an X-ray phase-contrast imaging system that can provide excellent soft tissue contrast of phase, attenuation, and small-angle scatter. We propose to replace the common system of G0, G1, and G2 gradings with a biprism array to replace the G1 grading and introduce a novel X-ray tube designed to replace the motion of the phase stepping grading G2. The proposed X-ray tube uses temporal multiplexing to provide simultaneous virtual “electronic phase stepping.” In this work the discrete Fourier transform is used to separate from the composite measurement individual X-ray phase contrast measurements sampled at different frequencies. The method performs a discrete Fourier transform of a composite refence sequence to obtain using the frequency amplitudes calibration factors needed to extract the X-ray phase contrast measurement amplitudes from the composite image. The composite reference sequence is the sum of the individual sequences, at different frequencies, with amplitudes of one. The method takes the discrete Fourier transform of this composite reference sequence; whereby, the amplitude of each frequency component is compared with the total sum of its stand-alone sequence amplitude. A calibration factor is determined so that the amplitude of this composite reference frequency times the calibration factor must equal the total sum of the sequence amplitude—the zero-frequency amplitude of the discrete Fourier transform of its stand-alone sequence. To demultiplex the composite measured signal these calibration factors are multiplied by the amplitudes of the frequency components of the discrete Fourier transform of the composite X-phase-contrast measurement to obtain the amplitude of each frequency encoded measurement. Using these calibration factors, we demonstrate with the discrete Fourier transform in Mathematica the extraction of individual images from a composite image that one would expect obtaining from our proposed new X-ray phase contrast imaging system. We then demonstrate as an example how using images from X-ray phase contrast data one can calculate phase, attenuation and the dark field images using grading phase step data supplied to use from Microworks, GmbH in Karlsruhe, Germany.

42 ENGINEERING↗

Jet Propulsion Laboratory: Annual Report 2002

The year 2002 brought advances on many fronts in our space exploration ventures. A new orbiter settled in at Mars and delivered tantalizing science results suggesting a vast store of water ice under the planet's surface, a discovery that may have profound consequences for exploring Mars. A long-lived spacecraft made its final fly-bys of Jupiter's moons, while another started its final approach toward Saturn and yet another flew by an asteroid on its way to a comet. A new ocean satellite began science observations, joined in Earth orbit by a pair of spacecraft measuring our home planets gravity field, as well as JPL instruments on NASA and Japanese satellites. A major new infrared observatory and a pair of Mars rovers were readied for launch. All told, JPL is now communicating with 14 spacecraft cast like gems across the velvet expanses of the solar system. It is a far cry from the early 1960's, when JPL engineers made prodigious efforts to get the first planetary explorers off the ground and into space - an achievement of which we were especially mindful this year, as 2002 marked the 40th anniversary of the first successful planetary mission, Mariner 2, which barely reached our closest planetary neighbor, Venus. Added to this anniversary were celebrations surrounding the 25th anniversaries of the launches of Voyagers 1 and 2, two remarkable spacecraft that are still flying and are actively probing the outer realms of the solar system. These events of the past and present provide an occasion for reflection on the remarkable era of exploration that we at the Jet Propulsion Laboratory are privileged to be a part of. As 2002 neared its end, the Laboratory had yet another reason for celebration, as a new five-year management contract between NASA and the California Institute of Technology was signed that calls for a closer working relationship with NASA and other NASA centers as a member of the 'One NASA' team. There is a strong emphasis on cost control and management, areas in which we can improve, enabling us to become more competitive. This new agreement again confirms NASA's trust and faith in Caltech and JPL, in which we should all take great pride. If the history of JPL were a book, we are on the verge of turning the page to one that promises to be one of the most exciting and busiest chapters in JPL's history. In 2003 and 2004, we will launch 11 spacecraft or major payloads. We will land two rovers on Mars; put a spacecraft in orbit around Saturn, deliver a probe to the surface of its largest moon, Titan, and map Titan's surface withimaging radar; send a spacecraft past a comet collecting samples from its tail, while another one is launched toward a comet impact; bring a capsule back to Earth with the first samples ever collected beyond the orbit of the Moon; map the skies in the ultraviolet as well as the infrared spectrum to unprecedented accuracy; and continue the mapping of ocean topography and winds on our home planet, Earth.

National Aeronautics and Space Administration (NAS↗

AdaNET services

MountainNet is a small firm which serves as a distribution center for AdaNET Services. These services include providing host systems and telecommunications for AdaNET, developing and supporting AdaNET Information Services, and developing a dynamic software inventory. AdaNET hosts are a Data General MV8000II and DEC VAX. Telecommunications are provided via the MountainNet private network and the Telenet public access dial network. Initially, the AdaNET Information Services will include software repositories, user communications and forums, software engineering information, bibliographic and library services, and an educational directory. The dynamic software inventory, which will become available in January 1990, will contain software engineering code and parts.

Digman, Michael↗

Publications of the Jet Propulsion Laboratory 1989

This bibliography describes and indexes by primary author the externally distributed technical reporting, released during 1989, that resulted from scientific and engineering work performed, or managed, by JPL. Three classes of publications are included: JPL publications in which the information is complete for a specific accomplishment; articles from the quarterly Telecommunications and Data Acquisition (TDA) Progress Report; and articles published in the open literature.

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Satellite Communications Using Commercial Protocols

NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space- based communications networks as well as expectations for future protocol development. It serves as a reference point from which the detailed work can be readily accessed. Areas that will be addressed include asynchronous-transfer-mode quality of service; completed and ongoing work of the Internet Engineering Task Force; data-link-layer protocol development for unidirectional link routing; and protocols for aeronautical applications, including mobile Internet protocol routing for wireless/mobile hosts and the aeronautical telecommunications network protocol.

Ivancic, William D.↗

Spectrally separable photon-pair generation in dispersion engineered thin-film lithium niobate

Existing nonlinear-optic implementations of pure, unfiltered heralded single-photon sources do not offer the scalability required for densely integrated quantum networks. Additionally, lithium niobate has hitherto been unsuitable for such use due to its material dispersion. We engineer the dispersion and the quasi-phasematching conditions of a waveguide in the rapidly emerging thin-film lithium niobate platform to generate spectrally separable photon pairs in the telecommunications band. Such photon pairs can be used as spectrally pure heralded single-photon sources in quantum networks. We estimate a heralded-state spectral purity of >94% based on joint spectral intensity measurements. Further, a joint spectral phase-sensitive measurement of the unheralded time-integrated second-order correlation function yields a heralded-state purity of (86 ± 5)%.

36 MATERIALS SCIENCE↗

Near-real-time TOMS, telecommunications and meteorological support for the 1987 Airborne Antarctic Ozone Experiment

The goal of the 1987 Airborne Antarctic Ozone Experiment was to improve the understanding of the mechanisms involved in the formation of the Antarctic ozone hole. Total ozone data taken by the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) played a central role in the successful outcome of the experiment. During the experiment, the near-real-time TOMS total ozone observations were supplied within hours of real time to the operations center in Punta Arenas, Chile. The final report summarizes the role which Research and Data Systems (RDS) Corporation played in the support of the experiment. The RDS provided telecommunications to support the science and operations efforts for the Airborne Antarctic Ozone Experiment, and supplied near real-time weather information to ensure flight and crew safety; designed and installed the telecommunications network to link NASA-GSFC, the United Kingdom Meteorological Office (UKMO), Palmer Station, the European Center for Medium-Range Weather Forecasts (ECMWF) to the operation at Punta Arenas; engineered and installed stations and other stand-alone systems to collect data from designated low-orbiting polar satellites and beacons; provided analyses of Nimbus-7 TOMS data and backup data products to Punta Arenas; and provided synoptic meteorological data analysis and reduction.

Ardanuy, P.↗