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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 541 records · Page 30

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NASA NTRS1971

Crew operations

The requirements for the activities involved, and the procedures used by the crew in the operations of the modular space station are presented. All crew-related characteristics of the station and its operations are indicated. The interior configuration and arrangement of each of the space station modules, the facilities and equipment in the module and their operation are described as related to crew habitability. The crew activities and procedures involved in the operation of the station in the accomplishment of its primary mission are defined. The operations involved in initial station buildup, and the on-orbit operation and maintenance of the station and its subsystems to support the experimental program are included. A general description of experiment operations is also given.

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NASA NTRS1972

Eigenvalues of singular differential operators by finite difference methods. II.

Note is made of an earlier paper which defined finite difference operators for the Hilbert space L2(m), and gave the eigenvalues for these operators. The present work examines eigenvalues for higher order singular differential operators by using finite difference methods. The two self-adjoint operators investigated are defined by a particular value in the same Hilbert space, L2(m), and are strictly positive with compact inverses. A class of finite difference operators is considered, with the idea of application to the theory of Toeplitz matrices. The approximating operators consist of a good approximation plus a perturbing operator.

Baxley, J. V.↗

NASA NTRS1972

Payload analysis for space shuttle applications (study 2.2). Volume 3: Payload system operations analysis (task 2.2.1)

The technical and cost analysis that was performed for the payload system operations analysis is presented. The technical analysis consists of the operations for the payload/shuttle and payload/tug, and the spacecraft analysis which includes sortie, automated, and large observatory type payloads. The cost analysis includes the costing tradeoffs of the various payload design concepts and traffic models. The overall objectives of this effort were to identify payload design and operational concepts for the shuttle which will result in low cost design, and to examine the low cost design concepts to identify applicable design guidelines. The operations analysis examined several past and current NASA and DoD satellite programs to establish a shuttle operations model. From this model the analysis examined the payload/shuttle flow and determined facility concepts necessary for effective payload/shuttle ground operations. The study of the payload/tug operations was an examination of the various flight timelines for missions requiring the tug.

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NASA NTRS1973

Phase operators and phase relations for photon states

For a quantized mode of the radiation field, the operator whose classical analog is the ordinary phase factor of the mode amplitudes has been shown to be nonunitary. A rigorous formulation of the phase P is given on the basis of the canonical factorization theorem. Many of the seemingly complex features of phase operators are found to be simple direct consequences of the general mathematical theory. It can be readily seen that P is a partial isometry but not a unitary operator. In contrast to the amplitude operator, it is found that P is not a spectral operator and that the set of phase eigenstates is not complete. Mathematically precise operator relations are developed, and a complete spectral analysis is given for each of the phase operators.-

Volkin, H. C.↗

NASA NTRS1975

Viking mission operations

The Viking Flight Team and ground system must operate in an integrated manner with the two orbiters and two landers to acquire the scientific data that will significantly increase our knowledge of Mars. Viking mission requires an adaptive mode of flight operations which permits reflection of the knowledge gained as the mission progresses into subsequent data acquisition operations. This includes reflection of both the knowledge gained about Mars and knowledge as to how well each of the four vehicles and the ground data system are performing. The requirement for adaptive mission operations has imposed special considerations in the Viking mission design, landing site selection, organization of the Flight Team and in the design and development of the operational tools required by this team. A mission operations strategy has been developed which governs the multivehicle adaptive mission operations.

Young, A. T.↗

NASA NTRS1976

Payload operation television system

The Payload Operation Television System is a high performance closed-circuit TV system designed to determine the feasibility of using TV to augment purely visual monitoring of operations, and to establish optimum system design of an operating unit which can ultimately be used to assist the operator of a remotely manipulated space-borne cargo loading device. The TV system assembled on this program is intended for laboratory experimentation which would develop operational techniques and lead to the design of space-borne TV equipment whose purpose would be to assist the astronaut-operator aboard a space station to load payload components. The equipment consists principally of a good quality TV camera capable of high resolving power; a TV monitor; a sync generator for driving camera and monitor; and two pan/tilt units which are remotely controlled by the operator.

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NASA NTRS1986

Computer simulation of on-orbit manned maneuvering unit operations

Simulation of spacecraft on-orbit operations is discussed in reference to Martin Marietta's Space Operations Simulation laboratory's use of computer software models to drive a six-degree-of-freedom moving base carriage and two target gimbal systems. In particular, key simulation issues and related computer software models associated with providing real-time, man-in-the-loop simulations of the Manned Maneuvering Unit (MMU) are addressed with special attention given to how effectively these models and motion systems simulate the MMU's actual on-orbit operations. The weightless effects of the space environment require the development of entirely new devices for locomotion. Since the access to space is very limited, it is necessary to design, build, and test these new devices within the physical constraints of earth using simulators. The simulation method that is discussed here is the technique of using computer software models to drive a Moving Base Carriage (MBC) that is capable of providing simultaneous six-degree-of-freedom motions. This method, utilized at Martin Marietta's Space Operations Simulation (SOS) laboratory, provides the ability to simulate the operation of manned spacecraft, provides the pilot with proper three-dimensional visual cues, and allows training of on-orbit operations. The purpose here is to discuss significant MMU simulation issues, the related models that were developed in response to these issues and how effectively these models simulate the MMU's actual on-orbiter operations.

Stuart, G. M.↗

NASA NTRS1988

Turnaround operations analysis for OTV. Volume 2: Detailed technical report

The objectives and accomplishments were to adapt and apply the newly created database of Shuttle/Centaur ground operations. Previously defined turnaround operations analyses were to be updated for ground-based OTVs (GBOTVs) and space-based OTVs (SBOTVs), design requirements identified for both OTV and Space Station accommodations hardware, turnaround operations costs estimated, and a technology development plan generated to develop the required capabilities. Technical and programmatic data were provided for NASA pertinent to OTV round and space operations requirements, turnaround operations, task descriptions, timelines and manpower requirements, OTV modular design and booster and Space Station interface requirements. SBOTV accommodations development schedule, cost and turnaround operations requirements, and a technology development plan for ground and space operations and space-based accommodations facilities and support equipment. Significant conclusion are discussed.

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NASA NTRS1987

Comparison of Nd 1.06 and 1.33 micron operation in various hosts

Performances of Nd in various hosts including Nd:YAG, Nd:YLF, Nd:BEL, and Nd:Cr:GSGG were characterized and compared for operation on the nominal 1.06 micron and 1.33 micron transitions. Comparison included continuous mode operation, normal mode operation, Q-switched operation, and gain measurements. Continuous lasing of Nd:Cr:GSGG under lamp pumping is reported for what may be the first time. Characterization included operation with different mirror reflectivities to obtain the internal losses, measurement of the upper laser level lifetime, measurement of the beam quality of the lasers operating under nominally similar circumstances, and measurement of the wavelength. These measurements should provide a comparison of the various Nd hosts under similar circumstances for a wide variety of operational modes and at both wavelengths of interest.

Barnes, Norman P.↗

NASA NTRS1988

Interactive orbital proximity operations planning system

An interactive graphical proximity operations planning system was developed, which allows on-site design of efficient, complex, multiburn maneuvers in a dynamic multispacecraft environment. Maneuvering takes place in and out of the orbital plane. The difficulty in planning such missions results from the unusual and counterintuitive character of orbital dynamics and complex time-varying operational constraints. This difficulty is greatly overcome by visualizing the relative trajectories and the relevant constraints in an easily interpretable graphical format, which provides the operator with immediate feedback on design actions. The display shows a perspective bird's-eye view of a Space Station and co-orbiting spacecraft on the background of the Station's orbital plane. The operator has control over the two modes of operation: a viewing system mode, which enables the exporation of the spatial situation about the Space Station and thus the ability to choose and zoom in on areas of interest; and a trajectory design mode, which allows the interactive editing of a series of way points and maneuvering burns to obtain a trajectory that complies with all operational constraints. A first version of this display was completed. An experimental program is planned in which operators will carry out a series of design missions which vary in complexity and constraints.

Grunwald, Arthur J.↗

NASA NTRS1989

A spatial operator algebra for manipulator modeling and control

A recently developed spatial operator algebra, useful for modeling, control, and trajectory design of manipulators is discussed. The elements of this algebra are linear operators whose domain and range spaces consist of forces, moments, velocities, and accelerations. The effect of these operators is equivalent to a spatial recursion along the span of a manipulator. Inversion of operators can be efficiently obtained via techniques of recursive filtering and smoothing. The operator algebra provides a high level framework for describing the dynamic and kinematic behavior of a manipulator and control and trajectory design algorithms. The interpretation of expressions within the algebraic framework leads to enhanced conceptual and physical understanding of manipulator dynamics and kinematics. Furthermore, implementable recursive algorithms can be immediately derived from the abstract operator expressions by inspection. Thus, the transition from an abstract problem formulation and solution to the detailed mechanizaton of specific algorithms is greatly simplified. The analytical formulation of the operator algebra, as well as its implementation in the Ada programming language are discussed.

Rodriguez, G.↗

NASA NTRS1990

Operations influence on Space Station Freedom

The Space Station Freedom is the first experience for NASA and its international partners in building a spacecraft that will be operated and maintained over a multi-year lifetime and that will be permanently manned. To ensure it functions safely and effectively, the operations community has become involved much earlier than in previous U.S. programs. This involvement has taken the form of defining requirements and analyzing the configuration, systems, and elements in terms of operations suitability and supportability. This early participation has had many effects on the definition and design of the Freedom Station. Examples of operations participation include the development of various operations concepts, design reference missions, contingency operations scenarios, and assembly operations assessments.

Accola, Anne L.↗

NASA NTRS1991

Transition operators in acoustic-wave diffraction theory. I - General theory. II - Short-wavelength behavior, dominant singularities of Zk0 and Zk0 exp -1

A formal theory of the scattering of time-harmonic acoustic scalar waves from impenetrable, immobile obstacles is established. The time-independent formal scattering theory of nonrelativistic quantum mechanics, in particular the theory of the complete Green's function and the transition (T) operator, provides the model. The quantum-mechanical approach is modified to allow the treatment of acoustic-wave scattering with imposed boundary conditions of impedance type on the surface (delta-Omega) of an impenetrable obstacle. With k0 as the free-space wavenumber of the signal, a simplified expression is obtained for the k0-dependent T operator for a general case of homogeneous impedance boundary conditions for the acoustic wave on delta-Omega. All the nonelementary operators entering the expression for the T operator are formally simple rational algebraic functions of a certain invertible linear radiation impedance operator which maps any sufficiently well-behaved complex-valued function on delta-Omega into another such function on delta-Omega. In the subsequent study, the short-wavelength and the long-wavelength behavior of the radiation impedance operator and its inverse (the 'radiation admittance' operator) as two-point kernels on a smooth delta-Omega are studied for pairs of points that are close together.

Hahne, G. E.↗

NASA NTRS1990

Operationally Efficient Propulsion System Study (OEPSS) data book. Executive summary

The study was initiated to identify operations problems and cost drivers for current propulsion systems and to identify technology and design approaches to increase the operational efficiency and reduce operations costs for future propulsion systems. To provide readily usable data for the Advanced Launch System (ALS) program, the results of the Operationally Efficient Propulsion System Study (OEPSS) were organized into a series of OEPSS Data Books as follows: Volume 1, Generic Ground Operations Data; Volume 2, Ground Operations Problems; Volume 3, Operations Technology; Volume 4, OEPSS Design Concepts; and Volume 5, OEPSS Final Review Briefing, which summarizes the activities and results of the study. Summarized here are the salient results of the first year. A synopsis of each volume listed above is presented.

Wong, George S.↗

NASA NTRS1993

Link monitor and control operator assistant: A prototype demonstrating semiautomated monitor and control

This article describes the approach, results, and lessons learned from an applied research project demonstrating how artificial intelligence (AI) technology can be used to improve Deep Space Network operations. Configuring antenna and associated equipment necessary to support a communications link is a time-consuming process. The time spent configuring the equipment is essentially overhead and results in reduced time for actual mission support operations. The NASA Office of Space Communications (Code O) and the NASA Office of Advanced Concepts and Technology (Code C) jointly funded an applied research project to investigate technologies which can be used to reduce configuration time. This resulted in the development and application of AI-based automated operations technology in a prototype system, the Link Monitor and Control Operator Assistant (LMC OA). The LMC OA was tested over the course of three months in a parallel experimental mode on very long baseline interferometry (VLBI) operations at the Goldstone Deep Space Communications Center. The tests demonstrated a 44 percent reduction in pre-calibration time for a VLBI pass on the 70-m antenna. Currently, this technology is being developed further under Research and Technology Operating Plan (RTOP)-72 to demonstrate the applicability of the technology to operations in the entire Deep Space Network.

Lee, L. F.↗

NASA NTRS1993

SPOT4 Operational Control Center (CMP)

CNES(F) is responsible for the development of a new generation of Operational Control Center (CMP) which will operate the new heliosynchronous remote sensing satellite (SPOT4). This Operational Control Center takes large benefit from the experience of the first generation of control center and from the recent advances in computer technology and standards. The CMP is designed for operating two satellites all the same time with a reduced pool of controllers. The architecture of this CMP is simple, robust, and flexible, since it is based on powerful distributed workstations interconnected through an Ethernet LAN. The application software uses modern and formal software engineering methods, in order to improve quality and reliability, and facilitate maintenance. This software is table driven so it can be easily adapted to other operational needs. Operation tasks are automated to the maximum extent, so that it could be possible to operate the CMP automatically with very limited human interference for supervision and decision making. This paper provides an overview of the SPOTS mission and associated ground segment. It also details the CMP, its functions, and its software and hardware architecture.

Zaouche, G.↗

NASA NTRS1993

An engineering database management system for spacecraft operations

Studies at ESOC have demonstrated the feasibility of a flexible and powerful Engineering Database Management System in support for spacecraft operations documentation. The objectives set out were three-fold: first an analysis of the problems encountered by the Operations team in obtaining and managing operations documents; secondly, the definition of a concept for operations documentation and the implementation of prototype to prove the feasibility of the concept; and thirdly, definition of standards and protocols required for the exchange of data between the top-level partners in a satellite project. The EDMS prototype was populated with ERS-l satellite design data and has been used by the operations team at ESOC to gather operational experience. An operational EDMS would be implemented at the satellite prime contractor's site as a common database for all technical information surrounding a project and would be accessible by the cocontractor's and ESA teams.

Cipollone, Gregorio↗

NASA NTRS1993

Intelligent systems and advanced user interfaces for design, operation, and maintenance of command management systems

Historically, command management systems (CMS) have been large and expensive spacecraft-specific software systems that were costly to build, operate, and maintain. Current and emerging hardware, software, and user interface technologies may offer an opportunity to facilitate the initial formulation and design of a spacecraft-specific CMS as well as to develop a more generic CMS system. New technologies, in addition to a core CMS common to a range of spacecraft, may facilitate the training and enhance the efficiency of CMS operations. Current mission operations center (MOC) hardware and software include Unix workstations, the C/C++ programming languages, and an X window interface. This configuration provides the power and flexibility to support sophisticated and intelligent user interfaces that exploit state-of-the-art technologies in human-machine interaction, artificial intelligence, and software engineering. One of the goals of this research is to explore the extent to which technologies developed in the research laboratory can be productively applied in a complex system such as spacecraft command management. Initial examination of some of these issues in CMS design and operation suggests that application of technologies such as intelligent planning, case-based reasoning, human-machine systems design and analysis tools (e.g., operator and designer models), and human-computer interaction tools (e.g., graphics, visualization, and animation) may provide significant savings in the design, operation, and maintenance of the CMS for a specific spacecraft as well as continuity for CMS design and development across spacecraft. The first six months of this research saw a broad investigation by Georgia Tech researchers into the function, design, and operation of current and planned command management systems at Goddard Space Flight Center. As the first step, the researchers attempted to understand the current and anticipated horizons of command management systems at Goddard. Preliminary results are given on CMS commonalities and causes of low re-use, and methods are proposed to facilitate increased re-use.

Potter, William J.↗