• Space Shuttle Payloads Support Capability

      Torres, Frank; Rockwell International (International Foundation for Telemetering, 1979-11)
      The NASA/Rockwell Space Shuttle with its highly versatile avionics and electrical provisions for use by the Shuttle payloads will provide an efficient system for future national space program activities and space program activities from foreign countries. This paper summarizes the avionics and electrical payload capabilities and interface characteristics. It includes a description of the command and data systems interface, the caution and warning system interface, and the aft flight deck accommodations; the electrical power distribution system; and the standard mixed cargo harness.
    • U. S. Domestic Communication Satellite Systems

      Martin, D. H.; The Aerospace Corporation (International Foundation for Telemetering, 1979-11)
      Domestic communication satellite (domsat) systems in the United States have a history of 14 years. Currently, several systems are in operation and another will be in early 1981. In recent years, many papers have been published, each describing certain details of a specific system. In contrast, this paper presents an overview and comparison of all the systems. As a background to this survey, the U. S. domsat history is briefly reviewed. The system overview then begins with a look at the satellites. Their basic designs are compared pictorially and through tabular data. Communication subsystems are also compared. The survey then goes on to the terminals, the terrestrial parts of the systems. Representative terminal characteristics are discussed. Finally, the various communication services offered by these systems are described.
    • Inertial Upper Stage/Shuttle Orbiter Communications

      Huth, G. K.; Udalov, S.; Axiomatix (International Foundation for Telemetering, 1979-11)
      The Inertial Upper Stage (IUS) system is intended for DOD and NASA space vehicle (S/V) launches from the Shuttle Orbiter. Prior to and during the IUS launch, commands must be transmitted to the S/V and IUS and the telemetry data must be communicated to the Orbiter. This paper describes the communication links between the IUS and the Orbiter, with particular emphasis on the RF link equipment and performance. The transponder equipment carried on board the IUS system is also described.
    • Landsat D High Density Tape Recorders

      Montgomery John H.; Martin Marietta Corporation (International Foundation for Telemetering, 1979-11)
      High density tape recorders are being provided by Martin Marietta Corporation to facilitate Landsat D data acquisition and processing. High rate data form the Landsat D Thematic mapper and from the multispectrial scanner are to be stored on high density recorders of 42, 28, and 14 track configurations. Successive stages of data processing will utilize higher error-free reproduce techniques and tape systems will provide ease of operation with a variety of differing record and reproduce data rates. The design and implementation of these recorders will be discussed.
    • International Telemetering Conference Proceedings, Volume 15 (1979)

      Unknown author (International Foundation for Telemetering, 1979-11)
    • Reconstructing Pulse-Code Modulation Telemetry Data with Dropouts

      Hull, M. L.; Mote, C. D., Jr.; Lamoreux, L. W.; University of California, Davis; University of California, Berkeley (International Foundation for Telemetering, 1979-11)
      A data handling system was developed which transfers serial pulse-code modulation (PCM) telemetry data from an analog tape to a digital tape for analysis on a digital computer. The PCM data were collected from field experiments in snow skiing which measured the excitation between the ski boot and the ski. PCM data were FM transmitted and stored on an analog tape recorder. In the laboratory, data were decoded from the tape and parallel input to a Nova minicomputer which buffered the data and wrote tapes compatible with a CDC 6400 computer. A custom-built PCM decoder provided control and status commands to drive the minicomputer interrupt logic. The data transfer rate was 50 kbits/s. Special consideration was given to the problem of information losses. Lost data frames were not stored by the minicomputer and the data time series on the digital tape is discontinuous at each loss point. Spectral analysis of data with discontinuities produces erroneous results. Fourier coefficients and power spectra were computed for both continuous and discontinuous signals. Discontinuities caused significant reductions in amplitude and increase in bandwidth of spectrum estimates. Unique software eliminated data discontinuities by reconstructing the original time-base with linearly interpolated pseudo-data. Results are presented which show the enhanced accuracy obtained in spectrum estimates with the reconstructed data.
    • Hardware Compressor Reduces Computer Loading

      Strock, O. J. "Jud"; EMR-Telemetry (International Foundation for Telemetering, 1979-11)
      A hardware Compressor examines measurement data prior to computer entry, discards redundant or otherwise uninteresting words, and passes the appropriate information with tags to a computer. Continuous rates of 100,000 to 1,000,000 words per second are accepted. Under some conditions, 95% to 98% of the data can be discarded while passing every measurement which is of value in real-time analysis.
    • The Command and Data Management System of Spacelab

      Bolton, Gordon R.; European Space Agency (ESA) ESTEC (International Foundation for Telemetering, 1979-11)
      This paper describes the Spacelab command and data management system and its support capabilities for various types of experiments in terms of data processing, display, recording, and multiplexing.
    • A Compatible STS/PAM D/RCA SATCOM Telemetry and Command System

      Hoedemaker, R.; Staloff, C.; RCA Astro-Electronics (International Foundation for Telemetering, 1979-11)
      This paper presents a solution to the problem of providing the electrical interface with the NASA Shuttle and PAM D for an RCA Satcom Communications Satellite. The paper addresses the transition to the NASA Shuttle from the present era of expendable launch vehicles as it applies to the command and telemetry electrical interfaces. Final preparation of the spacecraft for launch into the transfer orbit rests with the Orbiter crew rather than the spacecraft contractor launch team. The added dimension of crew safety and the importance of simplifying the preparation task led the requirement for Electrical Airborne Support Equipment (EASE). The conceptual design of this microcomputer-based equipment is described. The EASE monitors the health of the spacecraft and takes adaptive action where appropriate. It also sends prestored command lists to the spacecraft in response to crew-initiated keyboard command functions.
    • An Overview of TDRSS Ground Station

      Morran, Peter C.; Bebb, Joan E.; TRW DSSG (International Foundation for Telemetering, 1979-11)
    • Control Aspects of Multibeam or Multielement Spacecraft Antennas

      Foldes, Peter; General Electric Company, Space Division (International Foundation for Telemetering, 1979-11)
      With the rapid development of spacecraft systems the trend is toward more sophisticated and larger on-board antennas. Many of these antennas employ an array of radiating elements, either as part of a feed system illuminating a larger aperture optics or as the direct radiators. The main purpose of using multiple radiators instead of a radiator in conjunction with a large aperture is to introduce a much larger degree of freedom in achieving desirable antenna characteristics. If an antenna system contains n independent radiating elements then the amplitude and phase of each of these elements can be selected for desirable results.
    • MMS Command and Data Handling

      Kelley, R. L.; Raymond, H. A.; Fairchild Space and Electronics Company (International Foundation for Telemetering, 1979-11)
      The Command and Data Handling System which is part of the NASA Multi-mission Modular Spacecraft (MMS) represents a versatile time division multiple access approach to processing spacecraft commands and retrieving data on real-time, delayed or preprogrammed basis. This paper traces the command signals from operator keyboard to execution within the spacecraft and telemetry/data signals from on-board spacecraft measurement to display on the operator's CRT page. Key technical features throughout this end-to-end signal processing loop are described and discussed.
    • Correlation of Tape Dropouts with Data Quality

      Schoeck, Kenneth O.; Kobylecky, George M.; Vandenberg Air Force Base (International Foundation for Telemetering, 1979-11)
      When recording and reproducing telemetry data, signal dropouts are a prime concern to most tape users. The effect of particular depths and lengths of dropouts on data quality must be known before the acceptability of a tape for a specific application can be determined. This paper discusses the correlation of tape dropouts with data quality when recording predetection and post-detection telemetry data and IRIG timing on wideband instrumentation tape, as well as methods of reducing dropouts.
    • Super High Bit Rate Recording

      Wood, Tracy G.; Ampex Corporation (International Foundation for Telemetering, 1979-11)
      A radically different magnetic recording approach is proposed to solve the very high density and very high data rate requirements of the 1980's. In direct contrast to the industry's traditional approach of head-per-track longitudinal recording is a multi-track rotary helical recorder using narrow tracks. This technique is described. These narrow tracks, in conjunction with a novel development called "Automatic Scan Tracking" (AST), make possible the development of a family of recorders with data rates up to one (1) gigabits per second with user packing densities of five (5) megabits per square inch and a bit error rate performance better than one (1) part in a million (106) without aid of error detection and correction codes.
    • Spacecraft Minicomputer for Control of a Communications Payload

      Rhodes, Russell R.; Semprucci, Marilyn D.; Massachusetts Institute of Technology (International Foundation for Telemetering, 1979-11)
      The paper describes the design, use and testing of a spacecraft minicomputer. The minicomputer was designed as a controller for the communications payload of a Communications Satellite with about 100 communications channels. Each of the channels has very flexible control including variable data rate, Doppler offset, and flexible routing.
    • DMSP Block 5D-1 Computer Controlled Spacecraft

      McElroy, Stephen M.; Gomberg, Louis; Beest, Roger Te; SAMSO; RCA/AED (International Foundation for Telemetering, 1979-11)
      The Defense Meteorological Satellite Program (DMSP) Block 5D-1 satellite is the first of a new generation of DMSP long life satellites to utilize onboard programmable computers for spacecraft control functions. During ascent and orbit injection the computers perform the navigation, guidance, and control functions autonomously; during on-orbit operations, they perform attitude determination and control, command and control, and miscellaneous other control functions, with only modest interaction from the ground. Four DMSP Block 5D-1 satellites employing these computer controls are currently on orbit and operational. On-orbit experience shows that performance has exceeded all expectations with respect to reliability and satellite life-time. In addition to providing the control functions for which they were designed, the computers have provided additional benefits by allowing the control systems to be reprogrammed from the ground to overcome hardware failure and degradation in other on-board components. This paper describes the DMSP mission, gives a brief overview of the integrated spacecraft system configuration, and provides the details of the control systems used in the various mission phases. The hardware and software portions of the control systems are described and some examples are provided showing how the reprogrammable capability allowed several orbital anomalies to be overcome and satellite life extended.
    • Control of Large Communication Satellites

      Gran, Richard; Proise, Michael; Zislin, Alex; Grumman Aerospace Corporation (International Foundation for Telemetering, 1979-11)
      Control of large communication satellites becomes most difficult when the structure gets large enough that the structural motion severely impacts the ability to stabilize the RF antennas. This structural/control interaction means that the control engineer can no longer use "benign neglect" of the structural vibrations, but must design a control that has a bandwidth that exceeds the lowest structural vibratory frequency. This in itself is not a problem as long as the sensors and actuators are colocated. Eventually, the antennas have to be controlled independently and the assumption of colocated sensors and actuators is no longer reasonable. This begins the problem. In this paper, the various approaches that have been proposed for controlling large flexible spacecraft when the structural frequencies and the control frequencies overlap will be described. A new approach to the design of such systems will be described, and a reasonably complex example of a large satellite control will be described. The presentation will show a movie that was produced to illustrate the control of this structure and the consequence of using the approach described in the paper.
    • Future Modular Data Handling Concepts for Large Space Platforms

      Thompson, G. P.; ESA/ESTEC (International Foundation for Telemetering, 1979-11)
      With the ever-increasing competition for geostationary orbital positions, designers of applications satellites are looking more and more to the use of large multipurpose platforms to fly simultaneously a variety of payloads. This paper looks at the challenges these platforms provide in the field of data handling for individually launched and docking satellites, and reviews current European concepts and technologies which are being developed to meet these challenges.
    • The LEASAT Communications Satellite

      Dutcher, G. L.; Lankford, J. G.; Hughes Aircraft Company (International Foundation for Telemetering, 1979-11)
      Beginning in 1982 communication services will be provided to the U.S. Navy by a series of UHF communications satellites known as LEASAT. The communications payload will be carried on a new spacecraft bus developed as an optimum bus for space shuttle launches; the program is the first of its kind to take advantage of the full 15 foot shuttle payload bay diameter. Several new spacecraft design concepts are employed in this optimized bus. The communications payload incorporates transponders in the UHF and SHF regimes. Four distinct types of transponders are employed: wideband, narrowband, relay, and fleet broadcast. The functional characteristics of each type is described in detail. The frequency plan leads to a significant potential for passive generation of intermodulation products, and intermodulation considerations are an integral part of the spacecraft design.
    • Time Response Simulation of the Guidance and Control System of an Automatically Steered Wire-Following Vehicle

      Mukhopadhyay, Asok K.; Dobrotin, Boris M.; Jet Propulsion Laboratory (International Foundation for Telemetering, 1979-11)
      The purpose of the multi-mode evasive vehicle, as defined by the U.S. Army Armored Vehicle Command, is to provide an automatically steered moving platform for a target silhouette which will be used for tank gunnery evaluation. The vehicle, as well as its guidance and control systems, must be rugged enough to withstand battle conditions, rough terrain, hostile weather conditions, and the impact of dummy shells on its superstructure. The vehicle's steering and speed control are accomplished remotely by signals sent via a guide wire laid on the ground. The Army Wire-Following-Vehicle (WFV) represents new technology in the area of automatic vehicle guidance and has a host of potential applications, both military (such as a target drone) and civilian (such as underground mining and rescue as well as surface mass transit on electronic guide ways). For an high-order non-linear system, such as the WFV with its guidance and speed control subsystems, the final design must be generated and verified by non-linear time-response simulation. This paper describes the time-response simulation studies undertaken by the authors in support of the development and validation of the guidance/steering subsystem of the WFV (including the vehicular motion on some sample guided courses). Such simulation is the cheapest and quickest way to determine the design tolerances and hence, the field worthiness of the WFV. The WFV guidance system hardware design based on the continuous time-response simulation reported in this study has resulted in successful accomplishment of desired performance goals.