• Bubble Memories for Spacecraft Mass Storage Status and Potential

      Murray, Glenn W.; Rockwell International (International Foundation for Telemetering, 1978-11)
      A combination of solid state technology, high storage density and nonvolatility makes Bubble Memory Technology an attractive option for spacecraft system designers. It has the potential for not only replacing conventional spaceborne mass store media such as tape but also the flexibility to be configured into mass store system resembling disks providing the designer with memory organizations for space applications not previously available. The current state of this technology is assessed in terms of memory element, memory element packaging and system design with special attention to those aspects particularly relevant to space applications. Future developments in the technology and their impact on the capability and application are also considered.
    • Detection of Moving Optical Objects

      Burczewski, R. M.; Mohanty, N. C.; Rockwell International (International Foundation for Telemetering, 1978-11)
      This paper deals with the detection of a moving optical object in the presence of background, sensor or star and other noise. The algorithms are derived to estimate noise statistics, and its extrapolation, signal statistics, and the criterion for detecting the moving objects. The performance of the algorithm has also been derived.
    • GPS Overview and User Equipment Antijam Design

      Hemesath, Norbert B.; Hutchinson, William M.; Rockwell International (International Foundation for Telemetering, 1978-11)
      The Global Positioning System (GPS) features an all-weather global coverage navigation sensor with 0.01-nmi positioning accuracy. In the following paper, GPS is described with emphasis on antijam considerations developed in the USAF AFAL Generalized Development Model, GDM. Section 1 provides an overview of the GPS ground, space, and user segments. Section 2 describes antijam issues and techniques applicable to GPS. Section 3 describes the GDM design with emphasis on antijam. features. The objectives of the paper are thereby threefold. The first is to give an overview of GPS, how it works, its participants, and its status. The second is to provide a tutorial discussion of spread spectrum receiver design related to GPS (some knowledge of signal processing principles is therein assumed). The third is to provide an example of GPS receiver design which incorporates antijam features.
    • Performance Evaluation of Step Stare Sensor for Space-Based Air Vehicle Detection

      Ho, C. Q.; Rockwell International (International Foundation for Telemetering, 1978-11)
      Detection of aircraft by a space-based infrared sensor is a demanding task using near-term technology. To achieve sufficient sensitivity, background noise suppression is required because of the relatively weak target signal. Background noise suppression techniques, first order, second order, and higher order temporal differencing, spatial and temporal differencing, are analyzed and compared. Background noise due to both background drift and system vibration effects are calculated. Pixel-to-Pixel offset-induced background noise leakage is also evaluated.
    • The Space Shuttle Orbiter Communication and Tracking System

      Carrier, Louis M.; Pope, Warren S.; Rockwell International (International Foundation for Telemetering, 1978-11)
      During space flight, the communications and tracking system of the Space Shuttle orbiter uses S- and Ku-band links to provide tracking; reception of digitized voice, commands, and printed or diagramatic data at a maximum rate of 216 kilobits a second; and transmission of digitized voice, telemetry, television, and data at a maximum rate of 50 megabits a second. S-band links may be established directly with a ground station and both S- and Ku-band links may be routed through NASA's Tracking and Data Relay Satellite System A simultaneous capability to communicate with other satellites or spacecraft, using a variety of formats and modulation techniques on more than 850 S-band channels, is provided. UHF is used for communication with extravehicular astronauts. Audio and television subsystems serve on-board needs as well as interfacing with the RF equipment. During aerodynamic flight following entry, a UHF link provides two-way simplex voice communication with Air Traffic Control facilities. Air navigation aids include TACAN, a microwave scan-beam landing system and radar altimeters.
    • Space Shuttle Orbiter Processing, Monitoring, and Telemetry Systems

      Carrier, Louis M.; Robitaille, Richard A.; Rockwell International (International Foundation for Telemetering, 1978-11)
      The transportation vehicle for launching personnel and payloads into earth orbit during the 1980's and subsequent years will be NASA's space shuttle. The space shuttle flight system consists of an orbiter, an external tank, and two solid rocket boosters. The orbiter, a key element of the Space Shuttle, is launched into space like a conventional launch vehicle, performs on-orbit payload missions, enters the atmosphere, and lands much like a conventional commercial jet aircraft. This paper provides an overview of the Space Shuttle avionics with prime emphasis on how the orbiter's on-board processing, monitoring, and telemetry systems function during the on-orbit mission phase. Included is a description of the S-band and Ku-band RF transmission link and its relationship to the ground systems, payload interfaces, and support equipment. Also discussed are the flexibility of its instrumentation system (including capability to provide formats), features of the on-board monitoring systems (dedicated displays, cathode-ray tubes, and caution and warning systems), and methods for storing and processing data (recorders, mass memory, and on-board computers). The orbiter's avionic services to the payloads and the future growth of the Space Transportation System and the orbiter are also discussed briefly.