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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 1,405 records · Page 78
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Analysis of conditions for operating the S193 Rad/Scat in the solar pointing mode

The S193 Rad/Scat, although initially programmed for operating in the earth pointing mode, can be operated in the solar pointing mode as well. The usual coordinate systems for describing the S193 in orbit are defined. The instructions for the operation of the radiometer and scatterometer are presented in terms of standard Euler angles for these coordinate systems. A sample analysis for the scatterometer is described. The relationships between the various Euler angles and physically meaningful orbit parameters are defined.

Pintar, J.↗
NASA NTRS1997

Rocketdyne RBCC Concept Development

Rocketdyne is pursuing the conceptual design and development of a Rocket Based Combined Cycle (BBCC) engine for booster and SSTO, advanced reusable space transportation systems under the Advanced Reusable Transportation Technologies contract with NASA Marshall Space Flight Center. The Rocketdyne concept is a fixed geometry integrated rocket, ramjet, scramjet which is hydrogen fueled and uses hydrogen regenerative cooling. Vision vehicle integration studies have determined that scramjet operation to the range of Mach 10 to 12 has high payoff for low cost reusable space transportation. Rocketdyne is internally developing versions of the concept for other applications in high speed aircraft and missiles with hydrocarbon fuel systems. A subscale engine ground test program is underway for all modes of operation from takeoff to Mach 8. High altitude rocket tests will only be completed as part of the ground test program to validate high expansion ratio performance. A unique feature of the ground test series is the inclusion of dynamic trajectory simulation with real time Mach number, altitude, engine throttling, and RBCC mode changes in a specially modified freejet test facility at GASL. Preliminary cold flow air augmented rocket and all rocket test results have met program goals and have been used to integrate all modes of operation in a single combustor design with a fixed geometry inlet for design confirmation tests. A water cooled subscale engine is currently being fabricated for test during the early part of 1998.

Ortwerth, P.↗
NASA NTRS1974

Effect of anode ring arrangement on the spectroscopic characteristics of the NASA Lewis Bumpy Torus plasma

The modified Penning discharge in the NASA Lewis Bumpy Torus is normally produced by an anode ring at high voltage in each of the 12 magnetic mirror midplanes. For this investigation, the plasma was run with 12, 6, 3, and 1 anode rings. When 3 anode rings were used, the spectroscopically determined relative electron density and mean ion residence time increased by factors of 10 and 5, respectively, in one mode of operation. The discharge is observed to uniformly fill all bumps around the torus regardless of the anode arrangement and number. A plasma density on axis of 100 billion per cu cm is estimated for the 3-anode case in one mode of operation based on an observed discharge current to ion loss rate correlation and a measured mean ion residence time of .5 msec.

Richardson, R. W.↗
NASA NTRS1974

Effect of anode ring arrangement on the spectroscopic characteristics of the NASA Lewis bumpy torus plasma

The modified Penning discharge in the NASA Lewis Bumpy Torus is normally produced by an anode ring at high voltage in each of the 12 magnetic mirror midplanes. For this investigation, the plasma was run with 12, 6, 3, and 1 anode rings. When 3 anode rings were used, the spectroscopically determined relative electron density and mean ion residence time increase by factors of 10 and 5, respectively, in one mode of operation. The discharge is observed to uniformly fill all bumps around the torus regardless of the anode arrangement and number. A plasma density on axis of 10 to the 11th power cm/3 is estimated for the 3 anode case in one mode of operation based on an observed discharge current to ion loss rate correlation and a measured mean ion residence time of .5 msec.

Richardson, R. W.↗
NASA NTRS1971

Attitude control of an orbiting space vehicle.

Study of the normal and clamped modes of operation and dynamic response characteristics of the gimbaled control moment gyro (CMG) designed to fulfill the stringent pointing requirements of the Skylab telescope mount when the spacecraft is under the influence of both external and internal torques. The results indicate that the clamped mode of operation provides a feasible approach for significantly improving the system characteristics.

Sutherlin, D. W.↗
NASA NTRS2007

Asset surveillance system: apparatus and method

System and method for providing surveillance of an asset comprised of numerically fitting at least one mathematical model to obtained residual data correlative to asset operation; storing at least one mathematical model in a memory; obtaining a current set of signal data from the asset; retrieving at least one mathematical model from the memory, using the retrieved mathematical model in a sequential hypothesis test for determining if the current set of signal data is indicative of a fault condition; determining an asset fault cause correlative to a determined indication of a fault condition; providing an indication correlative to a determined fault cause, and an action when warranted. The residual data can be mode partitioned, a current mode of operation can be determined from the asset, and at least one mathematical model can be retrieved from the memory as a function of the determined mode of operation.

Bickford, Randall L.↗
NASA NTRS2005

Control Method for Video Guidance Sensor System

A method is provided for controlling operations in a video guidance sensor system wherein images of laser output signals transmitted by the system and returned from a target are captured and processed by the system to produce data used in tracking of the target. Six modes of operation are provided as follows: (i) a reset mode; (ii) a diagnostic mode; (iii) a standby mode; (iv) an acquisition mode; (v) a tracking mode; and (vi) a spot mode wherein captured images of returned laser signals are processed to produce data for all spots found in the image. The method provides for automatic transition to the standby mode from the reset mode after integrity checks are performed and from the diagnostic mode to the reset mode after diagnostic operations are commands is permitted only when the system is in the carried out. Further, acceptance of reset and diagnostic standby mode. The method also provides for automatic transition from the acquisition mode to the tracking mode when an acceptable target is found.

Richard T Howard↗
NASA NTRS2005

Control method for video guidance sensor system

A method is provided for controlling operations in a video guidance sensor system wherein images of laser output signals transmitted by the system and returned from a target are captured and processed by the system to produce data used in tracking of the target. Six modes of operation are provided as follows: (i) a reset mode; (ii) a diagnostic mode; (iii) a standby mode; (iv) an acquisition mode; (v) a tracking mode; and (vi) a spot mode wherein captured images of returned laser signals are processed to produce data for all spots found in the image. The method provides for automatic transition to the standby mode from the reset mode after integrity checks are performed and from the diagnostic mode to the reset mode after diagnostic operations are carried out. Further, acceptance of reset and diagnostic commands is permitted only when the system is in the standby mode. The method also provides for automatic transition from the acquisition mode to the tracking mode when an acceptable target is found.

Howard, Richard T.↗
NASA NTRS2011

Performance and Life Tests of a Regenerative Blower for EVA Suit Ventilation

Ventilation fans for future space suits must meet demanding performance specifications, satisfy stringent safety requirements for operation in an oxygen atmosphere, and be able to increase output to operate in buddy mode. A regenerative blower is an attractive choice due to its ability to meet these requirements at low operating speed. This paper describes progress in the development and testing of a regenerative blower designed to meet requirements for ventilation subsystems in a future space suit Portable Life Support Systems (PLSS). The blower assembly includes a custom-designed motor that has significantly improved in efficiency during this development effort. The blower was tested at both nominal and buddy mode operating points and head/flow performance and power consumption were measured. The blower was operated for over 1000 hours to demonstrate safe operation in an oxygen test loop at prototypical pressures. In addition, the blower demonstrated operation with the introduction of simulated lunar dust.

Izenson, Mike↗
NASA NTRS2012

Performance and Life Tests of a Regenerative Blower for EVA Suit Ventilation

Ventilation fans for future space suits must meet demanding performance specifications, satisfy stringent safety requirements for operation in an oxygen atmosphere, and be able to increase output to operate in buddy mode. A regenerative blower is an attractive choice due to its ability to meet these requirements at low operating speed. This paper describes progress in the development and testing of a regenerative blower designed to meet requirements for ventilation subsystems in future space suits. The blower includes a custom-designed motor that has significantly improved its efficiency. We have measured the blower s head/flow performance and power consumption under conditions that simulate both the normal and buddy mode operating points. We have operated the blower for TBD hours and demonstrated safe operation in an oxygen test loop at prototypical pressures. We also demonstrated operation with simulated lunar dust.

Izenson, Michael G.↗
NASA NTRS1967

Analog voicing detector responds to pitch

Modified electronic voice encoder /Vocoder/ includes an independent analog mode of operation in addition to the conventional digital mode. The Vocoder is a bandwidth compression equipment that permits voice transmission over channels, having only a fraction of the bandwidth required for conventional telephone-quality speech transmission.

Abel, R. S.↗
NASA NTRS1973

A study of the feasibility of mechanical pumps for use with the Pioneer-Venus probe mass spectrometer inlet system

A survey of mechanical vacuum pumps was completed. A small Roots blower for flight mass spectrometer applications was evaluated with respect to system operating parameters in a number of different modes of operation. The survey indicated that a metal bellows pump might be a viable alternative for the systems requirements. The results of the study are given, including current status of possible flight-type pumps, a systems analysis using available pumps, and recommendations for fabrication and tests of a potential flight-type pump.

Thomas, N. C.↗
NASA NTRS1974

Development of self-acting seals for helicopter engines

An experimental evaluation of a NASA-designed self-acting face seal for use in advanced gas turbine main shaft positions was conducted. The seal incorporated Rayleigh step pads (self-acting geometry) for lift augmentation. Satisfactory performance of the gas film seal was demonstrated in a 500-hour endurance test at speeds to 183 m/s (600 ft/sec, 54,000 rpm) and air pressure differential of 137 newtons per square centimeter (198.7 psi). Carbon wear was minor. Tests were also conducted with seal seat runout greater than that expected in engine operation and in a severe sand and dust environment. Seal operation was satisfactory in both these detrimental modes of operation.

Lynwander, P.↗
NASA NTRS1976

The imaging photopolarimeter - The first extraterrestrial spin-scan imager

The paper describes the imaging photopolarimeter used to take close-ups of Jupiter from Pioneers 10 and 11. The instrument operates in a steerable spin-scan mode of operation, contains a 1 in. diameter, f/3.4 Maksutov telescope with a focal plane aperture whose size is selectable. The paper examines those aspects of the design that are substantially influenced by the unusual design constraints, such as choice of detector and method of steering the telescope, and demonstrates the image processing and display techniques used to create the images from the telemetry and correct them for distortion and other defects.

Swindell, W.↗
NASA NTRS1986

Average power constraints in AlGaAs semiconductor lasers under pulse-position-modulation conditions

In some optical communications systems there are advantages to using low duty-cycle pulsed modulation formats such as pulse-position-modulation. However, because of intrinsic limitations of AlGaAs semiconductor lasers, the average power that they can deliver in a pulsed mode of operation is lower than in a CW mode. The magnitude of this problem and its implications are analyzed in this letter, and one possible solution is mentioned.

Katz, J.↗
NASA NTRS1993

A bi-directional two-phase/two-phase heat exchanger

This paper describes the design and test of a heat exchanger that transfers heat from one two-phase thermal loop to another with very small drops in temperature and pressure. The heat exchanger condenses the vapor in one loop while evaporating the liquid in the other without mixing of the condensing and evaporating fluids. The heat exchanger is bidirectional in that it can transfer heat in reverse, condensing on the normally evaporating side and vice versa. It is fully compatible with capillary pumped loops and mechanically pumped loops. Test results verified that performance of the heat exchanger met the design requirements. It demonstrated a heat transfer rate of 6800 watts in the normal mode of operation and 1000 watts in the reverse mode with temperature drops of less than 5 C between two thermal loops.

Ku, Jentung↗
NASA NTRS2004

Improving Control of Two Motor Controllers

A computer program controls motors that drive translation stages in a metrology system that consists of a pair of two-axis cathetometers. This program is specific to Compumotor Gemini (or equivalent) motors and the Compumotor 6K-series (or equivalent) motor controller. Relative to the software supplied with the controller, this program affords more capabilities and is easier to use. Written as a Virtual Instrument in the LabVIEW software system, the program presents an imitation control panel that the user can manipulate by use of a keyboard and mouse. There are three modes of operation: command, movement, and joystick. In command mode, single commands are sent to the controller for troubleshooting. In movement mode, distance, speed, and/or acceleration commands are sent to the controller. Position readouts from the motors and from position encoders on the translation stages are displayed in marked fields. At any time, the position readouts can be recorded in a file named by the user. In joystick mode, the program yields control of the motors to a joystick. The program sends commands to, and receives data from, the controller via a serial cable connection, using the serial-communication portion of the software supplied with the controller.

Toland, Ronald W.↗
NASA NTRS2011

Validation of Real-Time Data Processing for the Ground and Air-MSPI Systems

JPL is currently developing the multi-angle spectro-polarimetric imager (MSPI), targeted for the Aerosol-Cloud-Ecosystems (ACE) mission, as defined in the National Academies 2007 Decadal Survey. In preparation for the space instrument, the MSPI team has built two incremental camera systems (Ground- and Air-MSPI) to improve understanding of the proposed architecture. Ground-MSPI is a gimballed instrument used primarily for stationary observation and characterization of the imager and optics. The ER-2 based Air-MSPI operates in a step-and-stare mode, providing multi-angle imaging of a static target. This mode-of-operation simulates the observation scenario of the space instrument. Physically, MSPI is a pushbroom camera with a specialized frontend. Before imaging, light entering the camera passes through a pair of photoelastic modulators and a set of pattern polarizers. These optical elements act on the light to make polarimetric extraction computationally feasible. Calculating polarimetric parameters from the imager's data stream requires a real-time least-squares computation that produces coefficients of a truncated time-series expansion of the image. As reported in, the data processing algorithm can operate in real-time on a Xilinx Virtex-5 FPGA. Moving beyond verification with an onboard data source, the algorithm has been validated on a commercial development board interfaced with the ground camera. In addition, the algorithm has been instantiated within the Air-MSPI electronics board's FPGA, and in situ first-light has been achieved.

real-time data processing↗