269
269
May 21, 2011
05/11
by
Regler, Hans; Ruede, Ulric
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Finding the optimal position for the individual cells (also called functional modules) on the chip surface is an important and difficult step in the design of integrated circuits. This paper deals with the problem of relative placement, that is the minimization of a quadratic functional with a large, sparse, positive definite system matrix. The basic optimization problem must be augmented by constraints to inhibit solutions where cells overlap. Besides classical iterative methods, based on...
Topics: FRAGMENTATION, MANEUVERABLE SPACECRAFT, SOVIET SPACECRAFT, SPACECRAFT BREAKUP, EXPLOSIVE DEVICES,...
419
419
Jun 19, 2010
06/10
by
Bondi, M. J.; Wehrend, W. R., Jr
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Minimum energy reaction wheel control for Advanced Orbiting Solar Observatory performing raster scan over small celestial area
Topics: AOSO, MANEUVERABLE SPACECRAFT, RASTER SCANNING, REACTION WHEELS, AOSO, MANEUVERABLE SATELLITE,...
Mission models and payload requirements, systems integration requirements, costing analysis, and Teleoperator Maneuvering System benefits analysis are presented.
Topics: NASA Technical Reports Server (NTRS), MANEUVERABLE SPACECRAFT, PAYLOADS, TELEOPERATORS, COST...
Teleoperator Maneuvering System (TMS) versus integral spacecraft propulsion, spacecraft maintenance, cost benefits, launch prices, integral propulsion length penalties, remote maintenance versus EVA, potential weight reduction benefits, basing mode, mission models and payload requirements, and program profitability are discussed.
Topics: NASA Technical Reports Server (NTRS), COST ANALYSIS, MANEUVERABLE SPACECRAFT, TELEOPERATORS,...
On 6 Dec. 1991 Kosmos 2163, a maneuverable Soviet spacecraft which had been in orbit for 58 days, experienced a major breakup at an altitude of approximately 210 km. Although numerous pieces of debris were created, the fragments decayed rapidly leaving no long-term impact on the near-Earth environment. The assessed cause of the event is the deliberate detonation of an explosive device. Details of this event are presented.
Topics: NASA Technical Reports Server (NTRS), FRAGMENTATION, MANEUVERABLE SPACECRAFT, SOVIET SPACECRAFT,...
Primary and secondary covariances combined and projected into conjunction plane (plane perpendicular to relative velocity vector at TCA) Primary placed on x-axis at (miss distance, 0) and represented by circle of radius equal to sum of both spacecraft circumscribing radiiZ-axis perpendicular to x-axis in conjunction plane Pc is portion of combined error ellipsoid that falls within the hard-body radius circle
Topics: NASA Technical Reports Server (NTRS), COVARIANCE, EPHEMERIDES, MANEUVERABLE SPACECRAFT, RISK...
Orbital debris poses a significant threat to spacecraft health and safety. Recent events such as China's anti-satellite test and the Breeze-M rocket explosion have led to an even greater awareness and concern in the satellite community. Therefore, the National Aeronautics and Space Administration (NASA) has established requirements that routine conjunction assessment screening shall be performed for all maneuverable spacecraft having perigees less than 2000 km or within 200 km of geosynchronous...
Topics: NASA Technical Reports Server (NTRS), SPACE DEBRIS, RISK ASSESSMENT, MANEUVERABLE SPACECRAFT,...
Information is given in viewgraph form on control center operations at the Goddard Space Flight Center. Information is given on multi-mission, dedicated and attached payload support; the mission operations environment; technical challenges; Hubble Space Telescope (HST) science planning interface; operations engineering life cycle; Special Analysis of Maneuverable Satellites (SAMS) operations; and user interface applications.
Topics: NASA Technical Reports Server (NTRS), HUBBLE SPACE TELESCOPE, MANEUVERABLE SPACECRAFT, PROJECT...
230
230
May 27, 2011
05/11
by
Wise, Stephanie A.; Hopson, Purnell, Jr.; Mau, Johnny C
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Hybrid microelectronics containing both conventional electronic components and high-temperature superconductive films have been designed, fabricated, and tested. The devices operate from room temperature to 75K and perform d.c. four-probe resistance measurements on six superconductive specimens resident on each circuit. Four of these hybrid circuits were incorporated into the Materials In Devices As Superconductors (MIDAS) spaceflight experiment and evaluated over a 90-day period on the Mir...
Topics: ARTIFICIAL SATELLITES, MANEUVERABLE SPACECRAFT, MILITARY SPACECRAFT, VISIBILITY, SATELLITE...
The potential advantages of the Aeromaneuvering Orbit-to-Orbit Shuttle (AMOOS) over the all-propulsive Orbit Transfer Vehicle (OTV) are shown. In particular, the kit concept studies and the dual fueled AMOOS studies show its versatility and option potential over the all-propulsive vehicle. All of this potential of AMOOS and the Aeromaneuvering Recovery System (AMRS) depends upon the ability to control the trajectory during atmospheric flight and so use an ablative TPS. In turn, this TPS must be...
Topics: NASA Technical Reports Server (NTRS), AERODYNAMIC CHARACTERISTICS, MANEUVERABLE SPACECRAFT,...
Reacting to potential on-orbit collision risk in an operational environment requires timely and accurate communication and exchange of data, information, and analysis to ensure informed decision-making for safety of flight and responsible use of the shared space environment. To accomplish this mission, it is imperative that all stakeholders effectively manage resources: devoting necessary and potentially intensive resource commitment to responding to high-risk conjunction events and preventing...
Topics: NASA Technical Reports Server (NTRS), COLLISIONS, RISK, RESOURCES MANAGEMENT, DECISION MAKING,...
Project Argo is the design of a manned Space Transportation Vehicle (STV) that would transport payloads between LEO (altitude lying between 278 to 500 km above the Earth) and GEO (altitude is approximately 35,800 km above the Earth) and would be refueled and refurbished at the Space Station Freedom. Argo would be man's first space-based manned vehicle and would provide a crucial link to geosynchronous orbit where the vast majority of satellites are located. The vehicle could be built and...
Topics: NASA Technical Reports Server (NTRS), AEROASSIST, HUMAN FACTORS ENGINEERING, MANEUVERABLE...
Both feedback and feedforward control approaches for uncertain dynamical systems (in particular, with uncertainty in structural mode frequency) are investigated. The control objective is to achieve a fast settling time (high performance) and robustness (insensitivity) to plant uncertainty. Preshaping of an ideal, time optimal control input using a tapped-delay filter is shown to provide a fast settling time with robust performance. A robust, non-minimum-phase feedback controller is synthesized...
Topics: NASA Technical Reports Server (NTRS), CONTROL SYSTEMS DESIGN, CONTROL THEORY, DYNAMICAL SYSTEMS,...
Space station missions, their requirements, and architectural solutions are presented. Analyses of the following five mission categories are summarized: (1) science/applications, (2) commercial, (3) national security, (4) operational support, and (5) technology development.
Topics: NASA Technical Reports Server (NTRS), MISSION PLANNING, SPACE MISSIONS, SPACE STATIONS, ARTIFICIAL...
No abstract available
Topics: NASA Technical Reports Server (NTRS), SMALL SCIENTIFIC SATELLITES, AUTONOMOUS DOCKING, ORBITAL...
This paper addresses the problem of reorienting a rigid spacecraft from arbitrary initial conditions to prescribed final conditions with zero angular velocity. The control law analyzed is based on quaternion feedback and leaves the user to choose two gains as functions of position, angular rate, and time. For arbitrary initial states, conditions on the controller gains are identified that guarantee global asymptotic stability. For the special case of rest-to-rest reorientations, the control law...
Topics: NASA Technical Reports Server (NTRS), RIGID STRUCTURES, MANEUVERABLE SPACECRAFT, ROTATING BODIES,...
A cooperative autopilot is developed for the control of the relative attitude, relative position and absolute attitude of two maneuvering spacecraft during on orbit proximity operations. The autopilot consists of an open-loop trajectory solver which computes a nine dimensional linearized nominal state trajectory at the beginning of each maneuver and a phase space regulator which maintains the two spacecraft on the nominal trajectory during coast phases of the maneuver. A linear programming...
Topics: NASA Technical Reports Server (NTRS), ACTIVE CONTROL, ATTITUDE CONTROL, AUTOMATIC PILOTS,...
An assessment of computational uncertainties is presented for numerical methods used by NASA to predict laminar, convective aeroheating environments for Mars-entry vehicles. A survey was conducted of existing experimental heat transfer and shock-shape data for high-enthalpy reacting-gas CO2 flows, and five relevant test series were selected for comparison with predictions. Solutions were generated at the experimental test conditions using NASA state-of-the-art computational tools and compared...
Topics: NASA Technical Reports Server (NTRS), ASSESSMENTS, LAMINAR HEAT TRANSFER, CONVECTIVE HEAT TRANSFER,...
