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  • Other Sources  (415)
  • SPACECRAFT DESIGN, TESTING AND PERFORMANCE  (415)
  • 2025-2025
  • 1980-1984  (415)
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  • 1983  (227)
  • 1981  (188)
  • 1
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    Effects of antenna blockage on radio frequency performance of the microwave radiometer spacecraft (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Radio frequency scaled models of the microwave radiometer spacecraft suspended feed concept were tested to determine the effects of aperture blockage on the antenna radiation pattern. Contributors to the uncertainty of the test measurements were evaluated, and an estimate of the blockage effects was made for comparison with the test measurements. The gain loss budget associated with reflector performance characteristics (aperture blockage, surface reflectivity, reflector roughness, and defocus) was determined.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center The Microwave Radiometer Spacecraft; p 141-165
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  • 2
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    Systems design and analysis of the microwave radiometer spacecraft (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Systems design and analysis data were generated for microwave radiometer spacecraft concept using the Large Advanced Space Systems (LASS) computer aided design and analysis program. Parametric analyses were conducted for perturbations off the nominal-orbital-altitude/antenna-reflector-size and for control/propulsion system options. Optimized spacecraft mass, structural element design, and on-orbit loading data are presented. Propulsion and rigid-body control systems sensitivities to current and advanced technology are established. Spacecraft-induced and environmental effects on antenna performance (surface accuracy, defocus, and boresight off-set) are quantified and structured material frequencies and modal shapes are defined.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 69-94
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  • 3
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    Exceedance statistics of accelerations resulting from thruster firings on the Apollo-Soyuz mission (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Spacecraft acceleration resulting from firings of vernier control system thrusters is an important consideration in the design, planning, execution and post-flight analysis of laboratory experiments in space. In particular, scientists and technologists involved with the development of experiments to be performed in space in many instances required statistical information on the magnitude and rate of occurrence of spacecraft accelerations. Typically, these accelerations are stochastic in nature, so that it is useful to characterize these accelerations in statistical terms. Statistics of spacecraft accelerations are summarized.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Dyn. as Related to Lab. Expt. in Space; p 167-174
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  • 4
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    Contributions of orbital mechanics to conducting experiments in space (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Orbital mechanics as a discipline is principally concerned with solving the set of equations for analyzing the motion of a satellite under various conditions. This activity on the surface may not seem crucial to conducting experiments in space, but it provides insights into the way in which forces may influence these experiments. More directly, for experiments concerned with external targets, it provides predictions of the satellites's position and velcoity verus time, enabling extensive preflight planning and resulting in optimum use of on-orbit time.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Dyn. as Related to Lab. Expt. in Space; p 129-136
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  • 5
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    Spacecraft dynamic environments (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Zero-gravity conditions in Earth orbit cannot be obtained in the Shuttle Orbiter, however, through careful planning, the dynamic environment and its effects on experiments can be minimized. Futhermore, although the dynamic environment of the Shuttle Orbiter is to a large degree stochastics, it is possible to predict characteristics of this environments so that scientists and technologists can plan their experiments and mission managers can plan missions with a view toward minimizing the effects of spacecraft dynamics on experiments. Characteristics of the dynamic environment that might be predicted include typical and "worst case" values of vehicle acceleration for the anticipated acceleration sources, typical number of acceleration event, duration times of disctete acceleration events, bandwidth of acceleration time history, etc.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Dyn. as Related to Lab. Expt. in Space; p 115-120
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  • 6
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    Bootlace catenary concept for antenna shape control (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A preliminary design of the microwave radiometer spacecraft (MRS) using the bootlace catenary shaping concept was developed. The application of this radically different design for shape control of the antenna membrane was assessed and possible sources of inaccuracies and errors were investigated.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 205-213
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  • 7
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    Adaptive control system for large annular momentum control device (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A dual momentum vector control concept, consisting of two counterrotating rings (each designated as an annular momentum control device), was studied for pointing and slewing control of large spacecraft. In a disturbance free space environment, the concept provides for three axis pointing and slewing capabilities while requiring no expendables. The approach utilizes two large diameter counterrotating rings or wheels suspended magnetically in many race supports distributed around the antenna structure. When the magnets are energized, attracting the two wheels, the resulting gyroscopic torque produces a rate along the appropriate axis. Roll control is provided by alternating the radiative rotational velocity of the two wheels. Wheels with diameters of 500 to 800 m and with sufficient momentum storage capability require rims only a few centimeters thick. The wheels are extremely flexible; therefore, it is necessary to account for the distributed nature of the rings in the design of the bearing controllers. Also, ring behavior is unpredictably sensitive to ring temperature, spin rate, manufacturing imperfections, and other variables. An adaptive control system designed to handle these problems is described.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 169-187
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  • 8
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    Weight estimates and packaging techniques for the microwave radiometer spacecraft (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Estimates of total spacecraft weight and packaging options were made for three conceptual designs of a microwave radiometer spacecraft. Erectable structures were found to be slightly lighter than deployable structures but could be packaged in one-tenth the volume. The tension rim concept, an unconventional design approach, was found to be the lightest and transportable to orbit in the least number of shuttle flights.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 109-125
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  • 9
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    The microwave radiometer spacecraft. A design study: Executive summary (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A conceptual design was developed for a microwave radiometer spacecraft (MRS) using a large passive reflector, microwave radiometer, and advanced control concepts soil moisture mapping from microwave sensing for global crop forecasting. Mission requirements and tradeoffs were defined, and major subsystems (structural, electromagnetic surface, and attitude control) conceptually designed. An overview of the mission and a summary of the study results are presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 1-14
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  • 10
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    Acoustic and vibration environments for laboratory experiments in space (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The basic parameters of random noise and vibration are described, and typical environments for the launch phase and orbital operations are presented. For the latter, both acoustically induced and structure-borne, thruster-included vibration are addressed, using data obtained during the Skylab and Titan programs.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center Spacecraft Dyn. as Related to Lab. Expt. in Space; p 188-195
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  • 11
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    Elastic body dynamics (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Most of the structural dynamics resources allocated to the Space Shuttle are concentrated on the flight events which result in critical structural loads and/or minimum control stability margins. Since these events are primarily sub-orbital, the data base of interest to those involved in orbital experimentation is somewhat limited. A brief discussion of available data is given. Although estimates of peak acceleration levels and the associated frequency spectrum in the payload bay due to thrusting of the various control system thrusters were made, the actual levels and time histories must be based on updated structural math models and a detailed knowledge of the input forcing functions.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center Spacecraft Dyn. as Related to Lab. Expt. in Space; p 175-180
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  • 12
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    Interactions between spacecraft motions and the atmospheric cloud physics laboratory experiments (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: In evaluating the effects of spacecraft motions on atmospheric cloud physics laboratory (ACPL) experimentation, the motions of concern are those which will result in the movement of the fluid or cloud particles within the experiment chambers. Of the various vehicle motions and residual forces which can and will occur, three types appear most likely to damage the experimental results: non-steady rotations through a large angle, long-duration accelerations in a constant direction, and vibrations. During the ACPL ice crystal growth experiments, the crystals are suspended near the end of a long fiber (20 cm long by 200 micron diameter) of glass or similar material. Small vibrations of the supported end of the fiber could cause extensive motions of the ice crystal, if care is not taken to avoid this problem.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Dyn. as Related to Lab. Expt. in Space; p 34-35
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  • 13
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    Biaxial and electrostatic tensioning effects on thin membrane materials (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Thin membrane materials were subjected to biaxial and electrostatic tensioning loads to study techniques for maintaining surface smoothness of a thin membrane antenna. The basic mechanical and electrical setup for the tests is described and preliminary measurements of surface smoothness and surface deviation are presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 189-204
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  • 14
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    Effects of random distortions on the surface accuracy of a large antenna (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The effects of random reflector distortions or irregularities on a reflector's radiation pattern are discussed. The importance of such surface deviations with respect to a radiometric reflector antenna is addressed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 137-140
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  • 15
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    Preliminary design of tetrahedral truss reflector structure (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A baseline structure proposed for the microwave radiometer spacecraft (MRS) reflector is a large graphite-epoxy truss. The truss structure was selected to provide adequate stiffness to minimize control problems and to provide a low-expansion 'strong back' on which to mount and control reflector mesh panels. Details of the structural members, joints and assembly concepts are presented, a concept for the reflector mesh surface is discussed, and preliminary estimates of the mass and structural natural frequencies of the reflector system are presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 95-107
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  • 16
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    Radiometer design concepts for large aperture microwave radiometer spacecraft (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Concepts involving active and passive microwave systems for soil-moisture monitoring are discussed. It is shown that the first major development efforts should be directed toward the simpler passive design concepts. Subsequently, five passive design concepts for a microwave radiometer spacecraft are outlined and compared. Some common technology needs, such as large space structures and controls, are shown to exist. Also, some peculiar technology needs are identified, such as complicated phasing networks, dielectric lenses, tapered illumination, and reflector-surface irregularity and distortion control techniques. More detailed studies to address these design concepts and assess the associated technology needs are recommended.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 43-49
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  • 17
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    High-resolution passive microwave imaging of the surface of the Earth (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The physics of passive microwave observations of the Earth and the system requirements for high-resolution imaging within this spectral band are summarized. High resolution is achieved in a straightforward manner by increasing the size of the primary antenna. However, with a single receiver, it is shown that the combination of high resolution and crosstrack scanning cannot produce images which have valuable geophysical content. The concept of a multiple receiver array located in the focal plane is presented as the only practical solution to the dilemma. Exploring this concept, system requirements are generated which, for the first order, appear to offer solutions to the problem.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center The Mirowave Radiometer Spacecraft; p 3-41
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  • 18
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    Mission definition for a large-aperture microwave radiometer spacecraft (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: An Earth-observation measurements mission is defined for a large-aperture microwave radiometer spacecraft. This mission is defined without regard to any particular spacecraft design concept. Space data application needs, the measurement selection rationale, and broad spacecraft design requirements and constraints are described. The effects of orbital parameters and image quality requirements on the spacecraft and mission performance are discussed. Over the land the primary measurand is soil moisture; over the coastal zones and the oceans important measurands are salinity, surface temperature, surface winds, oil spill dimensions and ice boundaries; and specific measurement requirements have been selected for each. Near-all-weather operation and good spatial resolution are assured by operating at low microwave frequencies using an extremely large aperture antenna in a low-Earth-orbit contiguous mapping mode.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 17-32
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  • 19
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    Orbital environment dynamics (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Diurnal density variations of the upper atmosphere are described. Temperature distribution above the thermopause were mapped and extremes of temperature variation over the 11-year solar cycle were determined. Day and nigth density profiles in the upper atmosphere at sunspot minimum and at a time of exceptionally high solar activity are presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Dyn. as Related to Lab. Expt. in Space; p 121-128
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  • 20
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    Design of the space shuttle digital autopilot and resulting dynamic environment (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: This compilation progresses through the development of the Space Shuttle phase plane controller form fundamental considerations. Quantitative insight regarding the nature of the dynamic environment aboard the Shuttle is provided.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center Spacecraft Dyn. as Related to Lab. Expt. in Space; p 147-166
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  • 21
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    Electromagnetic design of a microwave radiometer antenna system (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A preliminary electromagnetic (EM) design of a radiometric antenna system was developed for the microwave radiometer spacecraft mission. The antenna system consists of a large spherical reflector and an array of feed horns along a concentric circular arc in front of the reflector. The reflector antenna was sized to simultaneously produce 200 contiguous 1 km diameter footprints with an overall beam efficiency of 90 percent, and the feed horns and feed horn array were designed to monitor the radiation from the footprints.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 129-136
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  • 22
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    Evolution and design characteristics of the microwave radiometer spacecraft (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The evolution of the design of the microwave radiometer spacecraft from conception to preliminary design is described. Alternatives and tradeoff rationale are described, and the configuration and structural design features that were developed and refined during the design processes are presented for the three structural configurations studied (two geodesic trusses and a flexible catenary).
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Microwave Radiometer Spacecraft; p 51-66
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  • 23
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    Dynamic behavior of particles in spacecraft (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The behavior of particles relative to a spacecraft frame of reference was examined. Significant spatial excursions of particles in space can occur relative to the spacecraft frame of reference as a result of drag deceleration of the vehicle. These vehicle excursions tend to be large as time increases. Thus, if the particle is required to remain in a specified volume, constraints may be required. Thus, for example, in levitation experiments it may be extremely difficult to turn off the forces of constraint which keep the particles in a specified region. This means experiments which are sensitive to disturbances may be very difficult to perform if perturbation forces are required to be absent.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Dyn. as Related to Lab. Expt. in Space; p 137-146
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  • 24
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    Defining critical point experiments for a space laboratory (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Three representative low-gravity experiments for a fluid near its liquid-vapor critical point are being defined. Two of these experiments require very careful measurements of properties of the fluid in thermodynamic equilibrium, while the third experiment is a series of optical observations of the phenomena which occur as a fluid is changed from one phase to two phases, either by cooling through the critical point, or by adiabatic expansion. There is concern that residual spacecraft motions may complicate the interpretation of the data from the proposed experiments. It is possible that the Spacelab environment will render certain desirable experiments impractical.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center Spacecraft Dyn. as Related to Lab. Expt. in Space; p 11-17
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  • 25
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    HZE particle shielding using confined magnetic fields (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The great rigidities characteristic of high energy heavy ion (HZE) particles are judged to preclude near term use of confined magnetic fields of reasonable dimensions and strengths for small spacecraft shielding on long duration manned missions. It is noted that a Mars mission-class shield, although effective against solar protons, would be useless for HZE particles unless the mass and size of the shield are increased by several orders of magnitude (to yield a shield comparable to those contemplated for permanent space stations).
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 20; 629
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  • 26
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    Approximations of satellite stability (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Modifications and corrections are presented to relations obtained in an investigation conducted by Szebehely (1978), who has discussed the problem of Hill's (1878) stability of satellites in the restricted problem of three bodies. Attention is given to an approximation of the Jacobian constant for the satellite, the critical value of the Jacobian constant, and approximate solutions.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Celestial Mechanics; 24; June 198
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  • 27
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    On vibration control of tethered satellite systems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The general dynamics of a shuttle supported tethered subsatellite system taking into account the longitudinal and three dimensional transverse vibrations is considered. It is noted that control of inherently unstable dynamics during retrieval of the subsatellite can be carried out by letting the rate of change length depend on the state variables in an appropriate manner. Control laws using linear feedback of inplane state variables and nonlinear feedback of out-of-plane state variables are proposed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 317-327
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  • 28
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    A design procedure for active control of beam vibrations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The transverse vibrations of beams is discussed and a methodology for the design of an active damping device is given. The Bernoulli-Euler equation is used to derive a transcendental transfer function, which relates a torque applied at one end of the beam to the rotational position and velocity at that point. The active damping device consists of a wire, a linear actuator and a short torque arm attached to one end of the beam. The action of the actuator varies a tension in the wire and creates a torque which opposes the rotation of the beam and thus damps vibration. A design procedure for such an active damper is given. This procedure shows the relationships and trade-offs between the actuator stroke, power required, stress levels in the wire and beam and the geometry of the beam and wire. It is shown that by consideration of the frequency response at the beam natural frequencies, the aforementioned relationships can be greatly simplified. Similarly, a simple way of estimating the effective damping ratios and eigenvalue locations of actively controlled beams is presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 305-316
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  • 29
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    Orbiting chains and rings (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Two very different, highly flexible, space structures proposed during the last decade which involve analytical solution of certain partial differential equations are discussed. The first structure is an array, or hanging chain of aluminum beads which would serve as a convenient communicator if, under the influence of the Earth's gravity gradient, it assumes a local vertical orientation as it circles the Earth. Two passive schemes have been proposed for damping the rigid modes: twist the wire at the ends to provide non-zero moment of inertia about the vertical, thereby inducing relative motion of the two tips during rigid pitch or roll, and thus exercising a damper; and introduce weak lossy springs between the end sections and the main section; thereby providing linear coupling between the springs and all the in-plane (pitch) modes. The second structure is a complete ring of satellites cabled together at synchronous altitude. By a slight increase in altitude, the cable is in tension. This configuration is, however, unstable, and an active feedback control scheme is required to stabilize it. A possible scheme involves local cable length adjustment based on measurement of local altitude and shape variations and their rates.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 329-336
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  • 30
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    Number and placement of control system sensors considering possible failures (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A methodology has been presented which is intended to assist the designer of a control system for a large space structure to decide how many sensors should be incorporated in the system and where they should be placed on the structure. This approach is intended to be especially useful in the early stages of the evolution of the system, before a complete control system concept has been defined. This methodology is based on a quantitative measure of the observability of the system for a given set of sensors. The effect of possible component failures during the mission period was incorporated in the measure. The question of sensor placement is then resolved by finding the locations which maximize the performance measure. The number of components to use cannot be determined by optimizing the measure because the observability always improves with increased number of sensors if they are optimally located. However, the improvement in the measure with component number can be determined, and this information can be used along with data on cost, power required, etc., to decide how many sensors to use.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 253-268
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  • 31
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    Active Control of Space Structures (ACOSS) model 2 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A complete description of the active control of space structures model #2 which is a simple but realistic evaluation model is given. The design of this system was driven by the desire to incorporate certain attributes into the overall system characteristics. The desired features were structural design based on realistic sizes and weights; a simple unclassified optical system with associated performance measures and tolerance; and a set of disturbances typical of equipment vibration and attitude control (slew). The resulting model is described in detail along with the resulting mode shapes and natural frequencies of the system. A description of the line-of-sight performance measure including theory and implementation is given.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 195-210
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  • 32
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    Introduction and survey on continuum models for repetitive lattice structures (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A brief introduction and survey to aid and familiarize researchers interested in the use of continuum modeling procedures applied towards large space structure technology are presented. The use of such structural models for the distributed control of large flexible lattice structures offers a significant advantage over a numerical approach.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 63-70
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    Control of flexible structures: A systematic overview of the problem (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A way of designing a control system using a finite model that accounts for the distributed nature of the control problem in a systematic way is described. This is accomplished by using a mode description of the system and from that description determining the number of modes that must be retained based on the performance and the disturbance descriptions. The design then uses a full order model that includes all of the dynamics: sensor, actuator, disturbance and flexible motion. The designs that result are simple, robust, perform well and have the added distinction of being easy to implement.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 49-61
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    Minimum information modelling of structural systems with uncertain parameters (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Work is reviewed wherein the design of active structural control is formulated as the mean-square optimal control of a linear mechanical system with stochastic parameters. In practice, a complete probabilistic description of model parameters can never be provided by empirical determinations, and a suitable design approach must accept very limited a priori data on parameter statistics. In consequence, the mean-square optimization problem is formulated using a complete probability assignment which is made to be consistent with available data but maximally unconstrained otherwise through use of a maximum entropy principle. The ramifications of this approach for both robustness and large dimensionality are illustrated by consideration of the full-state feedback regulation problem.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 71-88
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    On the analytical modeling of the nonlinear vibrations of pretensioned space structures (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Pretensioned structures are receiving considerable attention as candidate large space structures. A typical example is a hoop-column antenna. The large number of preloaded members requires efficient analytical methods for concept validation and design. Validation through analyses is especially important since ground testing may be limited due to gravity effects and structural size. The present investigation has the objective to present an examination of the analytical modeling of pretensioned members undergoing nonlinear vibrations. Two approximate nonlinear analysis are developed to model general structural arrangements which include beam-columns and pretensioned cables attached to a common nucleus, such as may occur at a joint of a pretensioned structure. Attention is given to structures undergoing nonlinear steady-state oscillations due to sinusoidal excitation forces. Three analyses, linear, quasi-linear, and nonlinear are conducted and applied to study the response of a relatively simple cable stiffened structure.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
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    Control structure interactions in large space structures Analysis using energy approach (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A simple energy approach to study the problem of control structure interactions in large space structures is presented. For the illustrative cases of free-free beam and free rectangular plate, the vibrational energy imparted during operation of constant and pulsed thrusters is found in a nondimensional form. Then based on a parametric study, suggestions are made on the choice of the thruster location and parameters to minimize the control structure interactions.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Aeronautical Society of India, Journal (ISSN 0001-9267); 35; 59-67
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    Approximation in control of flexible structures, theory and application (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The sense in which the feedback control law based on an approximate finite dimensional model of a continuous structure approximates a control law which is optimal for the distributed, or infinite dimensional, model of the structure is studied. From the analysis of the various control and stability issues associated with this basis question, useful information for designing finite dimensional compensators which produce near-optimal performance in infinite dimensional systems is gained. Some of the important predictions that can be made about large-order finite dimensional control laws, using the theory of infinite dimensional Riccati equations are indicated.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 383-389
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    Analysis of structural perturbations in systems via cost decomposition methods (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It has long been common practice to analyze linear dynamic systems by decomposing the total response in terms of individual contributions which are easier to analyze. Examples of this philosophy include the expansion of transfer functions using: (1) the superposition principle, (2) residue theory and partial fraction expansions, (3) Markov parameters, Hankel matrices, and (4) regular and singular perturbations. This paper summarizes a new and different kind of expansion designed to decompose the norm of the response vector rather than the response vector itself. This is referred to as "cost-decomposition' of the system. The notable advantages of this type of decomposition are: (a) easy application to multi-input, multi-output systems, (b) natural compatibility with Linear Quadratic Gaussian Theory, (c) applicability to the analysis of more general types of structural perturbations involving inputs, outputs, states, parameters. Property (c) makes the method suitable for problems in model reduction, measurement/actuator selections, and sensitivity analysis.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 465-475
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  • 39
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    Fixed-order dynamic compensation through optimal projection (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This paper reviews a formulation for the design of fixed-order dynamic compensation for flexible mechanical systems which is based upon explicit optimality conditions derived under the minimum data/maximum entropy stochastic modelling approach. The optimality conditions give rise to the novel concept of "optimal projection' which provides significant insight with regard to the compensator structure and permits earlier, more restricted and/or ad hoc design schemes to be seen as special cases of the present formulation.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 409-425
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  • 40
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    Hardware verification of distributed/adaptive control (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Adaptive control techniques are studied for their future application to the control of large space structures, where uncertain or changing parameters may destabilize standard control system designs. The approach used is to examine an extended Kalman filter estimator, in which the state vector is augmented with the unknown parameters. The associated Riccatti equation is linearized about the case of exact knowledge of the parameters. By assuming that parameter variations occur slowly, the filter complexity is reduced further yet. Simulations on a two degree-of-freedom oscillator demonstrate the parameter-tracking capability of the filter, and an implementation on the JPL Flexible Beam Facility using an incorrect model shows the adaptive filter/optimal control to be stable where a standard Kalman filter/optimal control design is unstable.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 337-350
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  • 41
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    The TOYSAT structural control experiment (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Lockheed TOYSAT experiment is described. The experiment was designed to test hypothesis concerning the application of optimal control theory to flexible spacecraft. The theory is presented, and results described.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: JPL Proc. of the Workshop on Appl. of Distributed System Theory to the Control of Large Space Struct.; p 269-285
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  • 42
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    Voltage gradients in solar array cavities as possible breakdown sites in spacecraft-charging-induced discharges (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A possible explanation for environmentally-induced discharges on geosynchronous satellites exists in the electric fields formed in the cavities between solar cells - the small gaps formed by the cover slides, solar cells, metallic interconnects and insulating substrate. When exposed to a substorm environment, the cover slides become less negatively charged than the spacecraft ground. Hence, it is possible for metallic surfaces (usually silver mesh) to be at a negative potential in a cavity that has a 'positive' surface above it. If the resultant electric field becomes large enough, then the interconnect could emit electrons (probably by field emission) which could be accelerated to space by the positive voltage on the covers. An experimental study was connected using a small solar array segment in which the interconnect potential was controlled by a power supply while the cover slides were irridated by monoenergetic electrons. It was found that discharges could be triggered when the interconnect potential became at least 500 volts negative with respect to the cover slides. Analytical modeling of satellites exposed to substorm environments indicates that such gradients are possible. Therefore, it appears that this trigger mechanism for discharges is possible. Details of the experiment and modeling study are presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
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  • 43
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    Control of reflector vibrations in large spaceborne antennas by means of movable dampers (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A simple approach to the design of feedback controls for damping the vibrations in large spaceborne antennas with flexible dish reflectors is proposed. The feedback controls consist of movable velocity-feedback dampers whose positions are determined by minimizing the rate of change of total vibrational energy at any time. The performance of the proposed feedback controls is studied via computer simulations.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: ASME, Transactions, Journal of Applied Mechanics (ISSN 0021-8936); 50; Sept
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  • 44
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    Identification of structural dynamics systems using least-square lattice filters (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 19, no. 2987, Accession no. A82-38965
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: (ISSN 0731-5090)
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  • 45
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    Booster and orbiter configurations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In the recent Future Space Transportation System (FSFS) study, a mission model was selected and a baseline vehicle which best met model requirements was shaped. This baseline was then analyzed for flight performance, structural and subsystem weight, and operation. Figures related to a payload of 150,000 lb in a 20-ft-diam by 90-ft-long envelope became the baseline. The existence of both space-based orbital transfer vehicles (OTVs) and a space station was assumed, taking into account a transfer of the payload from the launch vehicle to OTVs at the space station for final delivery to geosynchronous orbit (GEO). A computer-aided engineering system called Aerospace Vehicle Interactive Design (AVID) was employed in connection with baseline vehicle development. It was found that approximately three-fifth of the payload weight would be cryogenic propellants for OTVs. Attention is given to problems regarding the packaging of cryogenic tankage, a payload shroud, and studies of staging for two different booster propulsion units.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics (ISSN 0004-6213); 21; June 198
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  • 46
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    Optimum wing sizing of a single-stage-to-orbit vehicle (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 06, p. 822, Accession no. A82-17822)
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
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    Structures and mechanisms - Streamlining for fuel economy (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The design of prospective NASA space station components which inherently possess the means for structural growth without compromising initial system characteristics is considered. In structural design terms, space station growth can be achieved by increasing design safety factors, introducing dynamic isolators to prevent loads from reaching the initial components, or preplanning the refurbishment of the original structure with stronger elements. Design tradeoffs will be based on the definition of on-orbit loads, including docking and maneuvering, whose derived load spectra will allow the estimation of fatigue life. Improvements must be made in structural materials selection in order to reduce contamination, slow degradation, and extend the life of coatings. To minimize on-orbit maintenance, long service life lubrication systems with advanced sealing devices must be developed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics; 21; Mar. 198
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    Thermal control - Heat buses will operate like a public utility (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Active thermal control for the NASA space station concept requires long life heat rejection, highly versatile thermal transport, and efficient system integration. By a significant margin, the heat radiator will be the largest and most exposed portion of the space station thermal system. Transport requirements encompass the collection and movement of thermal energy from the space station's heat sources to the radiator heat sink at required temperature levels. In a decentralized thermal system, each space station module would collect and reject all of the waste heat generated, thereby requiring no module interconnections. This scheme does not, however, allow waste heat from one module to be used by another. In a centralized system, heat must be transported across module boundaries. A high capacity monogroove heat pipe has been developed to simplify space radiators design and operation.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics; 21; Mar. 198
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  • 49
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    Control - Demands mushroom as station grows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The NASA space station, which is presently in the planning stage, is to be composed of both rigid and nonrigid modules, rotating elements, and flexible appendages subjected to environmental disturbances from the earth's atmospheric gravity gradient, and magnetic field, as well as solar radiation and self-generated disturbances. Control functions, which will originally include attitude control, docking and berthing control, and system monitoring and management, will with evolving mission objectives come to encompass such control functions as articulation control, autonomous navigation, space traffic control, and large space structure control. Attention is given to the advancements in modular, distributed, and adaptive control methods, as well as system identification and hardware fault tolerance techniques, which will be required.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics; 21; Mar. 198
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  • 50
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    Large space structures raise testing challenges (1983)
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    Publication Date: 2011-08-18
    Description: The testing approaches and techniques necessary for combined ground and space verification for large space structures (LSS) to be deployed and assembled in space are explored. The size of LSS precludes full ground tests, thereby requiring assemblies, components, and their interactions to be examined on orbit. Ground tests involving drop tests and zero-g aircraft flights can be performed with scale models, but need computational compensation to eliminate gravitational and torque effects that do not occur in space. Structural rigidity also varies from ground to space, and can partly be accounted for in ground tests by using cable supports, although numerical modelling must remove the effects of the cables' presence. Long-term funding is recommended for on-orbit tests of components in order to build a data base for later testing and actual construction of LSS.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics (ISSN 0004-6213); 21; Oct. 198
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  • 51
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    Exceedance statistics of accelerations resulting from thruster firings on the Apollo-Soyuz mission (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Spacecraft acceleration resulting from firings of vernier control system thrusters is an important consideration in the design, planning, execution and post-flight analysis of laboratory experiments in space. In particular, scientists and technologists involved with the development of experiments to be performed in space in many instances required statistical information on the magnitude and rate of occurrence of spacecraft accelerations. Typically, these accelerations are stochastic in nature, so that it is useful to characterize these accelerations in statistical terms. Statistics of spacecraft accelerations are summarized. Previously announced in STAR as N82-12127
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4560); 20; May-June
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  • 52
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    Control of space stations (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: A study is made to develop controllers for the NASA-JSC Triangular Space Station and evaluate their performances to make recommendations for structural design and/or control alternatives. The control system design assumes the rigid body of the Space Station and developes the lumped parameter control system by using the Inverse Optimal Control Theory. In order to evaluate the performance of the control system, a Parameter Estimation algorithm is being developed which will be used in modeling an equivalent but simpler Space Station model. Finally, a scaled version of the Space Station is being built for the purpose of physical experiments to evaluate the control system performance.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Johnson (Lyndon B.) Space Center The 1983 NASA/ASEE Summer Faculty Fellowship Research Program Research Reports; NASA. Johnson (Lynd
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  • 53
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    Orbital Maneuvering Vehicle Simulation System On-Board Processing Logic (1983)
    In:  CASI
    Details
    Publication Date: 2014-09-11
    Description: The control logic for an Orbital Maneuvering Vehicle (OMV) Simulation system is developed. In order that better control over the vehicle can be exercised, several modifications to the vehicle are suggested. The need of better position feedback leads to the development of an alternative simpler but more reliable navigation system which is also discussed. The control logic is presented in pseudocode form, and can be implemented in FORTRAN and/or MACRO II.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Res. Rept.: 1983 NASA(ASEE Summer Faculty Fellowship Program; 67 p
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  • 54
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    Neutralizing charged-up spacecraft (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The problem of spacecraft charging is examined. The mechanism by which a spacecraft acquires a charge with respect to the ambient space environment is discussed. Methods used to avoid spacecraft dysfunction due to charging, including the use of electron and ion emitters, adequately conducting surfaces, and dielectric materials with high secondary-emission coefficients, are described. Special attention is given to the development, in the context of the Scatha program, of a computerized model which will allow the calculation of spacecraft potential for a given set of conditions.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: IEEE Spectrum; 18; July 198
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  • 55
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    The Shuttle tile story (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The structural problems associated with the reusable thermal protection system (TPS) of the Space Shuttle Orbiter are assessed. The ceramic insulation was placed on the aluminum in the form of about 30,000 tiles over approximately 70% of the Orbiter's exterior. The tiles were bonded to felt pads, and then the tile-pad structure was attached to the aluminum skin. As Orbiter design progressed, it was discovered that the TPS would have to withstand loads greater than initially predicted. The group tensile strength was less than that of the individual components. This was the primary factor contributing to the delay of the first flight. Values are given for Orbiter isotherms during a normal flight as well as the corresponding TPS distribution. The complete TPS assemblage is shown schematically, noting the sequence of assembling the tile components into a testing specimen. It is noted that tensile loads are applied to the strain-isolation path at discrete regions along transverse fiber bundles, causing a 50% reduction in system tensile strength. Procedures for strengthening the interface between the insulation and strain-isolation path are discussed and flight-simulation tests are outlined.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics; 19; Jan. 198
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  • 56
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    Minimum impulse limit cycle design to compensate for measurement uncertainties (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 19, p. 2997, Accession no. A82-38972
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Guidance, Control, and Dynamics (ISSN 0731-5090); 6; 432-436
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    Aeroassisted orbit transfer window opens on missions (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Studies of aeroassisted spacecraft orbit transfer conducted over the last two decades have produced an extensive literature and a well developed technology base, which suggest the obtainability of substantial performance improvements over all-propulsive spacecraft maneuvers. In such cases as that of multipass aerobraking, in which the vehicle is transferred from its approach velocity to a highly elliptic orbit about the planet by means of a rocket burn, followed by the circularization of the orbit through many high altitude atmospheric passes, the technology appears to be ready for application. In most other areas of aeroassisted orbit transfer, further work is required to reduce design risks to acceptable levels.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics (ISSN 0004-6213); 21; 36-43
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  • 58
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    Large Deployable Reflector (LDR) - A concept for an orbiting submillimeter-infrared telescope for the 1990s (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The history and background of the Large Deployable Reflector (LDR) are reviewed. The results of the June 1982 Asilomar (CA) workshop are incorporated into the LDR science objectives and telescope concept. The areas where the LDR may have the greatest scientific impact are in the study of star formation and planetary systems in the own and nearby galaxies and in cosmological studies of the structure and evolution of the early universe. The observational requirements for these and other scientific studies give rise to a set of telescope functional requirements. These, in turn, are satisfied by an LDR configuration which is a Cassegrain design with a 20 m diameter, actively controlled, segmented, primary reflector, diffraction limited at a wavelength of 30 to 50 microns. Technical challenges in the LDR development include construction of high tolerance mirror segments, surface figure measurement, figure control, vibration control, pointing, cryogenics, and coherent detectors. Project status and future plans for the LDR are discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Optical Engineering (ISSN 0091-3286); 22; 725-731
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  • 59
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    Control of large spaceborne antenna systems with flexible booms by mechanical decoupling (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A simple practical method for designing antenna-feed attitude control systems for large deployable spaceborne antenna systems with long flexible booms is proposed. The basic idea is to mechanically decouple the antenna-feed from the boom so that the feed-attitude control system can be designed without taking the boom dynamics into consideration, thus avoiding a complex control problem involving an infinite-dimensional distributed parameter system. The validity of the proposed method is substantiated by analytical and numerical studies using a mathematical model for the flexible boom which could undergo both bending and torsional vibrations. This approach leads to simple antenna-feed attitude control systems which are amenable to physical implementation.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Franklin Institute, Journal (ISSN 0016-0032); 315; May-June
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  • 60
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    Structures and subsystems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: New and improved materials combined with efficient structural design concepts have made an essential contribution towards the shaping of the present transportation system (STS), and now, for the replacement of the STS in the year 2005, new materials and novel designs are being studied to identify the technologies which should be developed for a low-cost future space transportation system (FSTS). Three basic structural arrangements were considered for the FSTS orbiter. They include a nonintegral tank arrangement, an integral-tank arrangement, and a hybrid of the first two. Three representative arrangements regarding wall constructions are considered. Each employs a blade-stiffened aluminum tank with reinforced closed-cell-foam cryogenic insulation. Attention is given to an aluminum-alloy structure, a graphite-epoxy structure, a graphite-polyimide structure, a carbon-carbon surface panel structure, a graphite-composite fuselage structure, serviceability and all-weather considerations, and structural concept ratings.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics (ISSN 0004-6213); 21; June 198
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  • 61
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    Experimental demonstration of static shape control (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 03, p. 344, Accession no. A82-13998
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: (ISSN 0731-5090)
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    System identification of large flexible structures by using simple continuum models (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Simple continuum models for the representation of large truss beams and truss platforms are constructed and employed in the solution of system identification problems permitting the significant reduction of the number of structural parameters. Two simple and easily computer-implemented algorithms are presented for the estimation of a simple model's equivalent structural parameters, and analytical and numerical solutions are given for the truss beam and truss platform cases in order to illustrate the basic concepts. It is found that model simplicity, in conjunction with the principle of least square erors, yields a feasible integration of structural and identification problems.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of the Astronautical Sciences (ISSN 0021-9142); 31; Jan
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  • 63
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    A concept for global crop forecasting (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The mission, instrumentation, and design concepts for microwave radiometer satellites for continuous crop condition forecasting and monitoring on a global basis are described. Soil moisture affects both crop growth and the dielectric properties of the soil, and can be quantified by analysis of reflected radiance passively received by orbiting spacecraft. A dedicated satellite reading a swath 200 km across, with 1 km and 1 K temperature resolution, could track the time-varying changes of solid moisture, sea ice, and water surface temperature. Launched by the Shuttle into an interim orbit, a boost would place the satellite in a 400 or 700 km orbit. Resolution requirements indicate a 45-725 m diam antenna, with 70 dB gain, operating at frequencies of 1.08, 2.03, and 4.95 GHz to ensure atmospheric transparency. Alternative structural concepts include either double-layer tetrahedral or single-layer geodesic trusses as the basic structural members. An analysis of the electrostatic positioning of the parabolic antenna membrane is outlined.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: vol. 36; Feb. 198
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  • 64
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    Research in structures and materials for future space transportation systems - An overview (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: (Previously cited in issue 14, p. 2544, Accession no. A79-34703)
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
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  • 65
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    Specular effects of Shuttle Orbiter radiators on a typical payload (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously cited in issue 17, p. 2894, Accession no. A81-39083)
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
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  • 66
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    Use of electromagnetic models in the optimal control of large space antennas (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A general approach to the optimal control of large space antennas based on their RF/structural characteristics is described. The approach consists of defining a cost functional based on the degradation of the RF performance of the antenna and using the structural model as the dynamic system. The method is applied to the design of an optimal controller for a 55-m, wrap-rib offset-fed antenna. Simulation results show that control energy consumption is reduced to aproximately one third of the energy used to achieve the same RF performance with traditional control strategies.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
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  • 67
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    Static shape forming for an electrostatically controlled membrane mirror (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A design concept is described permitting the static construction of a flexible membrane reflector for use in a radiometer spacecraft. The scheme utilizes electrostatic forces to actively shape the membrane toward a specified reflector surface with a required degree of precision. The formulations of the required electrostatic attractive forces, and stress and strain distributed in the membrane are presented in this paper in terms of curvilinear coordinates. An example is given to illustrate a variety of spherical membrane characteristics associated with different boundary conditions.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
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  • 68
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    Lifting entry vehicle mass reduction through integrated thermostructural/trajectory design (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 05, p. 749, Accession no. A80-18335
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 20; 589-596
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  • 69
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    Automatic thermal control switches (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 24, p. 3750, Accession no. A82-48067
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Spacecraft and Rockets (ISSN 0022-4650); 20; 553-558
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  • 70
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    Control of large space structures using Annual Momentum Control Devices (AMCD's) (1981)
    In:  CASI
    Details
    Publication Date: 2017-10-02
    Description: A controller design approach for large space structures, which proposes the use of several Annular Momentum Control Devices (AMCD's) for structural damping enhancement, and either torque actuators of AMCD's for primary attitude control, was investigated. The damping enhancement controller makes the system asymptotically stable under certain relatively simple conditions. The closed-loop stability of the system with the primary attitude controller as well as the overall controller was established. It is shown that the same AMCD's can be used for the actuation of the damping enhancement controller and the primary attitude controller. Numerical results were obtained for a finite-element model of a large, thin, completely free, flat aluminum plate.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: AGARD Spacecraft Pointing and Position Control; 12 p
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  • 71
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    Materials characterization study of conductive flexible second surface mirrors (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: The status of prequalification and qualification work on conductive flexible second surface mirrors is described. The basic material is FEP Teflon witn either aluminium or silver vacuum deposited reflectors. The top layer has been made conductive by deposition of layer of a indium oxide. The results of a prequalification program comprised of decontamination, humidity, thermal cycling, thermal shock and vibration tests are presented. Thermo-optical and electrical properties. The results of a prequalification program comprised of decontamination, humidity, thermal cycling, thermal shock and vibration tests are presented. Thermo-optical and electrical properties, the electrostatic behavior of the materials under simulated substorm environment and electrical conductivity at low temperatures are characterized. The effects of simulated ultra violet and particles irradiation on electrical and thermo-optical properties of the materials are also presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 237-260
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  • 72
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    Preliminary comparison of material charging properties using single-energy and multienergy electron beams (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: Results of tests designed to compare the charging properties of spacecraft material under a monoenergetic beam and under a continuously distributed beam are summarized. In the test setup the electron source was mounted in the top of a cylindrical vacuum chamber. A sheet of 5-mil-thick Kapton was placed on an insulated metal substrate at the bottom of the vacuum chamber. The dc current arriving on the substrate was measured and a field meter measured the potential of the test sample. A retarding potential analyzer measured the energy spectrum of the incident electron beam. With the monoenergetic beam, the sample charged to 12 kV and electrical discharges occurred. With the multi-energy spectra the samples charged to only 6 kV and 4 kV, and no discharger were observed. In these experiments, no effort was made to duplicate the spectra occurring in space. The tests were intended to simply to compare spacecraft material charging properties using monoenergetic and continuous multi-energy beams.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 129-132
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  • 73
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    Energy consumption analysis of the Venus Deep Space Station (DSS-13) (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: This report continues the energy consumption analysis and verification study of the tracking stations of the Goldstone Deep Space Communications Complex, and presents an audit of the Venus Deep Space Station (DSS 13). Due to the non-continuous radioastronomy research and development operations at the station, estimations of energy usage were employed in the energy consumption simulation of both the 9-meter and 26-meter antenna buildings. A 17.9% decrease in station energy consumption was experienced over the 1979-1981 years under study. A comparison of the ECP computer simulations and the station's main watt-hour meter readings showed good agreement.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: The Telecommun. and Data Acquisition Rept.; p 114-123
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  • 74
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    Experimental validation of a numerical model predicting the charging characteristics of Teflon and Kapton under electron beam irradiation (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: The effect differential charging of spacecraft thermal control surfaces is assessed by studying the dynamics of the charging process. A program to experimentally validate a computer model of the charging process was established. Time resolved measurements of the surface potential were obtained for samples of Kapton and Teflon irradiated with a monoenergetic electron beam. Results indicate that the computer model and experimental measurements agree well and that for Teflon, secondary emission is the governing factor. Experimental data indicate that bulk conductivities play a significant role in the charging of Kapton.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 65-73
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  • 75
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    Bulk charging and breakdown in electron-irradiated polymers (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: High energy electron irradiations were performed in an experimental and theoretical study of ten common polymers. Breakdowns were monitored by measuring currents between the electrodes on each side of the planar samples. Sample currents as a function of time during irradiation are compared with theory. Breakdowns are correlated with space charge electric field strength and polarity. Major findings include evidence that all polymers tested broke down, breakdowns remove negligible bulk charge and no breakdowns are seen below 20 million V/m.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 33-51
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  • 76
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    Large space structures controls research and development at Marshall Space Flight Center: Status and future plans (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Work performed in Large Space Structures Controls research and development program at Marshall Space Flight Center is described. Studies to develop a multilevel control approach which supports a modular or building block approach to the buildup of space platforms are discussed. A concept has been developed and tested in three-axis computer simulation utilizing a five-body model of a basic space platform module. Analytical efforts have continued to focus on extension of the basic theory and subsequent application. Consideration is also given to specifications to evaluate several algorithms for controlling the shape of Large Space Structures.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Structural Dyn. and Control of Large Space Struct., 1982; p 215-220
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  • 77
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    Partitioning of large space structures vibration control computations (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: The vibration control of large space structures is studied. It is found to be computationally demanding. Distribution of the vibration control computations among central and local processors can significantly reduce the throughput required from the central processor and may also result in improved performance due to reduced transport lag.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Structural Dyn. and Control of Large Space Struct., 1982; p 195-200
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  • 78
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    Research on the control of large space structures (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The research effort on the control of large space structures at the University of Houston has concentrated on the mathematical theory of finite-element models; identification of the mass, damping, and stiffness matrix; assignment of damping to structures; and decoupling of structure dynamics. The objective of the work has been and will continue to be the development of efficient numerical algorithms for analysis, control, and identification of large space structures. The major consideration in the development of the algorithms has been the large number of equations that must be handled by the algorithm as well as sensitivity of the algorithms to numerical errors.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Structural Dyn. and Control of Large Space Struct., 1982; p 221-233
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  • 79
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    A program plan for the development of fault tolerant large space systems (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The need for fault tolerance in Large Space systems is discussed. The unique characteristics of LSS which affect fault tolerance are described. The status of fault tolerant research for LSS is described. A program plan to validate and demonstrate the concept of fault tolerance for LSS is developed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Structural Dyn. and Control of Large Space Struct., 1982; p 175-180
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  • 80
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    Component number and placement in large space structure control (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Studies are carried out to assist the designer of the control system for a large flexible space structure in his choice of how many actuators and sensors to incorporate in the system, and where to locate them on the structure. The degree of controllability and minimum control energy strategy for driving the system are described.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Structural Dyn. and Control of Large Space Struct., 1982; p 161-174
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  • 81
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    Robust precision pointing control of large space platform payloads (1983)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Large space structure (LSS) secondary controllers to enhance inherent damping, and primary controllers for controlling rigid-body modes and structural modes are discussed. It was concluded that LSS control is stable and robust and offers promise. Further investigation is needed on the effects of actuator/sensor bandwidth.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Structural Dyn. and Control of Large Space Struct., 1982; p 121-134
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  • 82
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    Control of structures in space (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Various topics related to the control of large space structures are discussed. Equations of motion for distributed systems, eigenvalue problems, modal equations, control implementation, and the Langley beam experiment are discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Structural Dyn. and Control of Large Space Struct., 1982; p 111-120
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  • 83
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    The dynamics and control of large flexible space structures (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Large, flexible orbiting systems proposed for possible use in communications, electronic orbital based mail systems, and solar energy collection are discussed. The size and low weight to area ratio of such systems indicate that system flexibility is now the main consideration in the dynamics and control problem. For such large, flexible systems, both orientation and surface shape control will often be required. A conceptual development plan of a system software capability for use in analysis of the dynamics and control of large space structures technology (LSST) systems is discussed. This concept can be subdivided into four different stages: (1) system dynamics; (2) structural dynamics; (3) application of control algorithms; and (4) simulation of environmental disturbances. Modeling the system dynamics of such systems in orbit is the most fundamental component. Solar radiation pressure effects and orbital and gravity gradient effects are discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Structural Dyn. and Control of Large Space Struct., 1982; p 91-110
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  • 84
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    Role of energetic particles in charging/discharging of spacecraft dielectrics (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: The role that energetic particles in the substorm plasma have on the charging and discharging of typical dielectric layers used on spacecraft was investigated using spectra and pitch angle distributions measured in situ on the SCATHA spacecraft prior to and during a few kilovolt differential charging event in eclipse conditions. The particle spectra was input to deposition codes that determine the dose rate as a function of depth in Kapton and Teflon layers used in an experiment on SCATHA. The calculated ambient dose rates of a few rads/sec throughout the bulk of the samples are sufficiently high that radiation damage levels are reached on the time scale of 1 year. Surface dose is a factor of 100 higher. Bulk conductivity profiles were obtained from the dose rates using empirical relationships. The radiation induced bulk conductivities calculated at the peak charging time are found to be smaller than the intrinsic dark conductivity range of solar conditioned Kapton but higher than the corresponding value for Teflon.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 74-85
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  • 85
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    Design of an arc-free thermal blanket (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: The success of a multilayer thermal blanket in eliminating arcing is discussed. Arcing is eliminated by limiting the surface potential to well below the threshold level for discharge. This is achieved by enhancing the leakage current which results in conduction of the excess charge to the spacecraft structure. The thermal blanket consists of several layers of thermal control (space approved) materials, bonded together, with Kapton on the outside, arranged in such a way that when the outer surface is charged by electron irradiation, a strong electric field is set up on the Kapton layer resulting in a greatly improved conductivity. The basic properties of matter utilized in designing this blanket method of charge removal, and optimum thermo-optical properties are summarized.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 261-266
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  • 86
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    Charging and discharging characteristics of a rigid solar array (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: Two rigid solar array panels were subjected to a simulated geosynchronous orbit substorm environment. During the charging sequence, distributions of accumulated surface charge were measured under eclipse and sunlight conditions. Discharge events were characterized with respect to voltage pulse signatures and amplitudes on the solar array bus leads. Post-exposure analysis of the solar array panels indicated that the electrical characteristics were not degraded in spite of the substantial discharge actvity. However, significant cratering and discoloration of the Tedlar dielectric were observed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 228-236
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  • 87
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    Tank testing of a 2500-cm2 solar panel (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: A 50 cm by 50 cm solar array panel test patch was investigated for spacecraft charging and arcing effects. Bombardment with monochromatic electron was carried out. Some objectives of the test were: (1) to estimate at what voltage of electron bombardment arcing would be probable; (2) to find whether the arc's energy would be tolerable or damagingly large; (3) to try and separate thermal and photoeffects; and, (4) to see whether materials used were such as to minimize arcing. Some conclusions were: In sunlight the tracking data relay satellite's solar panel which has ceria glass on the front and conductive paint on the backside is probably a good design for reducing charge-up. In a geomagnetic substorm simulated in testing there will be arcing at the interconnects during eclipse and transitions into and out of eclipse in testing especially in view of the very cold temperatures that will be reached by this lightweight array. Ceria-doped glass is preferred to fused silica glass for reducing charge build up. The Kapton bare patch should still be conductively painted. The differential voltages on the panel determine when arcing first begins, and the electron beam voltages vary depending upon whether the metallic structure is directly grounded or semifloating.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 211-227
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  • 88
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    Electrostatic discharging behaviour of Kapton irradiated with electrons (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: The electrostatic charging and discharging of Kapton when irradiated with monoenergetic electrons of 5 to 30 keV energy were studied. The leakage currents and rates of discharging always increased with the incident electron energy and flux, whereas the surface voltage showed a more complex behavior depending on the thickness of the material: for the thinner films it exhibited a maximum and then fell at higher energies. The surface voltage, the rate of discharging, and the peak current and total charge flow during a discharge were enhanced as the temperature was decreased from 70 C to -180 C, and were accompanied by a decreasing leakage current. Visible light or the presence of an aluminum coating on the irradiated surface caused reductions in the surface voltage and changes in the discharging characteristics. The results are discussed in terms of the leakage currents and the secondary emission of electrons. Photomicrographs taken after irradiation, and photographs of samples during irradiation, show good correlations between the positions of light flashes and of pinholes produced by the discharge arcs.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 96-114
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  • 89
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    Electron-beam-charged dielectrics: Internal charge distribution (1981)
    In:  Other Sources
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    Publication Date: 2016-06-07
    Description: Theoretical calculations of an electron transport model of the charging of dielectrics due to electron bombardment are compared to measurements of internal charge distributions. The emphasis is on the distribution of Teflon. The position of the charge centroid as a function of time is not monotonic. It first moves deeper into the material and then moves back near to the surface. In most time regimes of interest, the charge distribution is not unimodal, but instead has two peaks. The location of the centroid near saturation is a function of the incident current density. While the qualitative comparison of theory and experiment are reasonable, quantitative comparison shows discrepancies of as much as a factor of two.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Research Center Spacecraft Charging Technol., 1980; p 17-32
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  • 90
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    An analytical investigation of shape control of large space structures by applied temperatures (1983)
    In:  Other Sources
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    Publication Date: 2018-12-01
    Description: An analytical procedure for the static shape control of flexible space structures subjected to thermal distortions is developed which is based on prescribing temperatures in control elements having much higher coefficients of thermal expansion than the main structure. The temperatures at the control elements are defined so as to minimize the overall thermal distortion of the structure from its ideal shape, and a matrix equation is obtained which can be solved for the set of optimum control temperatures. A formulation of the procedure for continuous structures governed by differential equations and a formulation for discrete (finite element modeled) structures governed by matrix equations are presented. The equations from the continuous formulation are employed for the shape control of a simple beam distorted by nonuniform heating, and the discrete formulation is applied in a general purpose finite-element structural analysis computer program for the shape control of a 750 m radiometer antenna reflector dish subjected to orbital heating. A reduction in thermal distortion by a factor of nearly 50 was obtained with the use of only seven control elements. Results for four different sets of control locations for the antenna are presented in which reductions in distortion of up to a factor of four were obtained.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
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  • 91
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    Study of robotics systems applications to the space station program (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: Applications of robotics systems to potential uses of the Space Station as an assembly facility, and secondarily as a servicing facility, are considered. A typical robotics system mission is described along with the pertinent application guidelines and Space Station environmental assumptions utilized in developing the robotic task scenarios. A functional description of a supervised dual-robot space structure construction system is given, and four key areas of robotic technology are defined, described, and assessed. Alternate technologies for implementing the more routine space technology support subsystems that will be required to support the Space Station robotic systems in assembly and servicing tasks are briefly discussed. The environmental conditions impacting on the robotic configuration design and operation are reviewed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-173703 , NAS 1.26:173703 , KTR-108
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  • 92
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    Space station needs, attributes, and architectural options. Volume 1. Executive summary (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: The initial space station should be manned, placed in 28.5 deg orbit, and provide substantial economic, performance, and social benefits. The most beneficial space station capabilities include: a space test facility; a transport harbor; satellite servicing and assembly; and an observatory. A space industrial park could be added once further development effort validates the cost and expanding commercial market for space processed materials. The potential accrued gross mission model benefit derived from these capabilities is $5.9B without the industrial park, and $9.3B with it. An unclassified overview of all phases of the study is presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-173710 , NAS 1.26:173710 , SA-SSP-RP007
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  • 93
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    Space station needs, attributes and architectural options. Volume 3, attachment 1, task 1: Mission requirements (1983)
    In:  CASI
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    Publication Date: 2019-06-28
    Description: The development and systems architectural requirements of the space station program are described. The system design is determined by user requirements. Investigated topics include physical and life science experiments, commercial utilization, U.S. national security, and remote space operations. The economic impact of the space station program is analyzed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-173716 , NAS 1.26:173716 , LMSC/D889718-VOL-3/1-TASK-1
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 94
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    Space station needs, attributes and architectural options study (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: All the candidate Technology Development missions investigated during the space station needs, attributes, and architectural options study are described. All the mission data forms plus additional information such as, cost, drawings, functional flows, etc., generated in support of these mission is included with a computer generated mission data form.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-173699 , NAS 1.26:173699 , D180-27477-7-VOL-7-3
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 95
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    Space station needs, attributes, and architectural options: Technology development (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The technology development of the space station is examined as it relates to space station growth and equipment requirements for future missions. Future mission topics are refined and used to establish a systems data base. Technology for human factors engineering, space maintenance, satellite design, and laser communications and tracking is discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-173697 , NAS 1.26:173697 , MDC-H0538
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 96
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    Tanker orbit transfer vehicle and method (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: A method and apparatus for transportation between orbits are presented. A tanker orbit transfer vehicle includes two stages each of which includes a fuel container. The first stage may be left in an intermediate parking orbit while the second stage goes on to carry out a mission, thereafter to return to rendezvous and dock with the first stage. Fuel carried by the first stage may be utilized for travel of the two stages between the starting orbit and the parking orbit, and for return to the starting orbit. An aerobrake may be included in the system for use in the return to the initial orbit.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 97
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    Development of deployable structures for large space platforms. Volume 2: Design development (1983)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: Design evolution, test article design, test article mass properties, and structural analysis of deployable platform systems are discussed. Orbit transfer vehicle (OTV) hangar development, OTV hangar concept selection, and manned module development are discussed. Deployable platform systems requirements, material data base, technology development needs, concept selection and deployable volume enclosures are also discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-170914 , NAS 1.26:170914 , SSD-83-0094-2-VOL-2
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 98
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    Observations of charging dynamics (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Plasma data from the University of California, San Diego, Auroral Particles experiments on Applied Technology satellites 5 and 6 are used to investigate the dynamics of natural charging events. Both eclipse and daylight charging events are considered, and typical responses are illustrated by data from specific events. Two different physical processes are found to be involved in the charging process. One of these is straightforward: the spacecraft structure potential responds rapidly to changes in the environment, typically changing by hundreds of volts in a few seconds. The other process is more subtle: differential charging and potential barrier formation precede structural charging and determine the time scale; typically, tens of minutes are required for the potential to change by several hundreds of volts. The latter process is found to be predominately responsible for daylight charging on both spacecraft.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Geophysical Research (ISSN 0148-0227); 88; July 1
    Format: text
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    NASA TECHNICAL REPORTS
  • 99
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    Benefits and costs of low thrust propulsion systems (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The results of costs/benefits analyses of three chemical propulsion systems that are candidates for transferring high density, low volume STS payloads from LEO to GEO are reported. Separate algorithms were developed for benefits and costs of primary propulsion systems (PPS) as functions of the required thrust levels. The life cycle costs of each system were computed based on the developmental, production, and deployment costs. A weighted criteria rating approach was taken for the benefits, with each benefit assigned a value commensurate to its relative worth to the overall system. Support costs were included in the costs modeling. Reference missions from NASA, commercial, and DoD catalog payloads were examined. The program was concluded reliable and flexible for evaluating benefits and costs of launch and orbit transfer for any catalog mission, with the most beneficial PPS being a dedicated low thrust configuration using the RL-10 system.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: AIAA PAPER 83-1248
    Format: text
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    NASA TECHNICAL REPORTS
  • 100
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    Space station propulsion system trade study (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: This study evaluates alternative space station propulsion system options for a range of space station configurational and operational architectures. Space station propulsion requirements ranging from those representative of the first generation space station to those of an advanced space station with a space based OTV are considered. A methodology for comparing the candidate propulsion technologies is developed which considers design/development/qualification and operational costs, system mass, performance, reliability, and other relevant parameters. Advanced propulsion systems are shown to reduce space station costs by providing higher performance but to require a larger front end investment for development and qualification. This study indicates that if the full potential of such systems is to be realized, then low cost implementations of this technology must be developed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: AIAA PAPER 83-1220
    Format: text
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    NASA TECHNICAL REPORTS
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