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Results for “operational vibration environment”

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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

The response of rotating machinery to external random vibration

A high-speed turbogenerator employing gas-lubricated hydrodynamic journal and thrust bearings was subjected to external random vibrations for the purpose of assessing bearing performance in a dynamic environment. The pivoted-pad type journal bearings and the step-sector thrust bearing supported a turbine-driven rotor weighing approximately twenty-one pounds at a nominal operating speed of 36,000 rpm. The response amplitudes of both the rigid-supported and flexible-supported bearing pads, the gimballed thrust bearing, and the rotor relative to the machine casing were measured with capacitance type displacement probes. Random vibrations were applied by means of a large electrodynamic shaker at input levels ranging between 0.5 g (rms) and 1.5 g (rms). Vibrations were applied both along and perpendicular to the rotor axis. Response measurements were analyzed for amplitude distribution and power spectral density. Experimental results compare well with calculations of amplitude power spectral density made for the case where the vibrations were applied along the rotor axis. In this case, the rotor-bearing system was treated as a linear, three-mass model.

Tessarzik, J. M.↗
NASA NTRS1973

Discrete component microwave amplifiers.

Several 2-3 GHz amplifiers using discrete variable components have been designed and tested. A power output of 6.5 watts with 30-mw drive and 29% efficiency has been obtained from a three-stage amplifier operating at 2.25 GHz. The unit has a 3 db bandwidth of 100 MHz and is stable with respect to temperature changes, a vacuum environment, and mechanical vibration. Significant problems arising from the use of discrete components have not been encountered.

Rippy, R. R.↗
NASA NTRS1991

Large space structures and systems in the space station era: A bibliography with indexes (supplement 03)

Bibliographies and abstracts are listed for 1221 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1991 and June 30, 1991. Topics covered include large space structures and systems, space stations, extravehicular activity, thermal environments and control, tethering, spacecraft power supplies, structural concepts and control systems, electronics, advanced materials, propulsion, policies and international cooperation, vibration and dynamic controls, robotics and remote operations, data and communication systems, electric power generation, space commercialization, orbital transfer, and human factors engineering.

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NASA NTRS1995

In-flight radiometric calibration of AVIRIS in 1994

The AVIRIS sensor must be calibrated at the time it measures spectra from the ER-2 airborne platform in order to achieve research and application objectives that are both quantitative and physically based. However, the operational environment inside the Q-bay of the ER-2 at 20 km altitude differs from that in the AVIRIS laboratory with respect to temperature, pressure, vibration, and high-frequency electromagnetic fields. Experiments at surface calibration targets are used in each flight season to confirm the accuracy of AVIRIS in-flight radiometric calibrations. For these experiments, the MODTRAN radiative transfer code is constrained by using in situ measurements to independently predict the upwelling spectral radiance arriving at AVIRIS for a specific calibration target. AVIRIS calibration is validated in flight by comparing the MODTRAN-predicted radiance to the laboratory-calibrated radiance measured by the AVIRIS sensor for the same time over the calibration target. We present radiometric calibration results for the AVIRIS in-flight calibration experiment held at the beginning of the 1994 flight season.

Green, Robert O.↗
NASA NTRS2017

Successful Space Flight of High-Speed InGaAs Photodiode Onboard the International Space Station

Photonic systems are required for several space applications, including satellite communication links and lidar sensors. Although such systems are ubiquitous in terrestrial applications, deployment in space requires the constituent components to withstand extreme environmental conditions, including wide operating temperature range, mechanical shock and vibration, and radiation. These conditions are significantly more stringent than alternative standards, namely Bellcore GR-468 and MIL-STD 883, which may be satisfied by typical, commercially available, photonic components. Furthermore, it is very difficult to simultaneously reproduce several aspects of space environment, including exposure to galactic cosmic rays (GCR), in a laboratory. Therefore, it is necessary to operate key photonic components in space to achieve a technology readiness level of 7 and beyond. Accordingly, the International Space Station (ISS) provides an invaluable test bed for qualifying such components for space missions. We present a fiber-pigtailed photodiode module, having a -3 dB bandwidth of 16.8 GHz, that survived 18 months on the ISS as part of the Materials International Space Station Experiment (MISSE) 7 mission. This module was launched by NASA Langley Research Center on November 16, 2009 on the Space Shuttle Atlantis (STS-129), as part of their lidar transceiver components. While orbiting on the ISS in a passive experiment container, the photodiode module was exposed to extreme temperature cycling from -157 degrees Celsius to +121 degrees Celsius 16 times a day, proton radiation from the inner Van Allen belt at the South Atlantic Anomaly, and galactic cosmic rays. The module returned to Earth on the Space Shuttle Endeavor (STS-134) on June 1, 2011 for further characterization. The post flight test of the photodiode module, shown in Fig. 1a, demonstrates no change in the module's performance, thus proving its survivability during launch and in space environment.

Joshi, Abhay↗
NASA NTRS2018

Laser power supply thermo-structural analysis for the Mars 2020 rover

Operation of the Laser Power Supply (LPS) module provides the dual challenge of high power dissipation, and the need for strict dielectric isolation, while needing to survive in an environment on Mars that will see a chilly night-time temperature of -123°C, and to a daytime instrument environment in excess of 50°C. Additionally, power restrictions prevent the use of survival heating during the night. The harsh mechanical vibration environment of launch and landing provides an additional challenge to reliability. A multi-physics simulation was created that took into account temperature property variations, as well as solving the transient analysis that also included rapid variation in power-pulsing during the operation of the laser. The steady state analysis employed a more traditional finite element based analysis, but with provisions for Mars gas convection and thermal radiation.

Tuman, David↗
NASA NTRS2018

Mars 2020 Rover Laser Power Supply Thermomechanical Analysis

Operation of the Laser Power Supply (LPS) module provides the dual challenge of high power dissipation, and the need for strict dielectric isolation, while needing to survive in an environment on Mars that will see a chilly night-time temperature of -123°C, and to a daytime instrument environment in excess of 50°C. Additionally, power restrictions prevent the use of survival heating during the night. The harsh mechanical vibration environment of launch and landing provides an additional challenge to reliability. A multi-physics simulation was created that took into account temperature property variations, as well as solving the transient analysis that also included rapid variation in power-pulsing during the operation of the laser. The steady state analysis employed a more traditional finite element based analysis, but with provisions for Mars gas convection and thermal radiation.

Tuman, David↗
NASA NTRS1979

Grazing incidence imaging telescope for X-ray astronomy using sounding rockets

A sounding rocket flight to image a point X-ray source and to determine the detector background characteristics in a space environment is evaluated. The verification of the HRI detector design in a flight environment is described. The environmental factors, including ambient neutral and charged particle densities, the electromagnetic radiation field, and the vibration and acceleration induced at launch, that affect the operations of the HRI are discussed.

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NASA NTRS2005

Interpreting the International Space Station Microgravity Environment

The International Space Station (ISS) serves as a platform for microgravity research for the foreseeable future. A microgravity environment is one in which the effects of gravity are drastically reduced which then allows physical experiments to be conducted without the overpowering effects of gravity. A physical environment with very low-levels of acceleration and vibration has been accomplished by both the free fall associated with orbital flight and the design of the International Space Station. The International Space Station design has been driven by a long-standing, high-level requirement for a microgravity mode of operation. The Space Acceleration Measurement System has been in operation for nearly four years on the ISS measuring the microgravity environment in support of principal investigators and to characterize the ISS microgravity environment. The Principal Investigator Microgravity Services project functions as a detective to ascertain the source of disturbances seen in the ISS microgravity environment to allow correlation between that environment and experimental data. Payload developers need to predict the microgravity environment that will be imposed upon an experiment and ensure that the science and engineering requirements will be met. The Principal Investigator Microgravity Services project is developing n interactive tool to predict the microgravity environment at science payloads based on user defined operational scenarios. These operations (predictions and post-analyses) allow a researcher to examine the microgravity acceleration levels expected to exist when their experiment is operated and then receive an analysis of the environment which existed during their experiment operations. Presented in this paper will be descriptions of the environment predictive tool and an investigation into a previously unknown disturbance in the ISS microgravity environment.

DeLombard, Richard↗
DOE OSTI2025

Applying Mechanistic Co-Design Towards Room-Temperature Organic, Optical, and Multiple-Center Molecular Qubits

The next generation of qubits, the building blocks of quantum technologies, are designed using molecules. Molecular qubits have natural advantages over solid-state equivalents in biological and chemical sensing. Chemistry allows the properties of molecular qubits to be fine-tuned, such as the ability of multiple qubits to work together using qubit-qubit coupling. Molecules and structures containing multiple qubits, made from both inorganic and organic elements, are developed in this work to bring quantum technologies closer to room-temperature operation. The goal is achieved by understanding how the core of the qubit, known as spin, interacts with the vibrating parts of the molecule, other spins, and the surrounding environment. A combined approach involving theory, spectroscopy, and synthesis is used to achieve the design goal.

36 MATERIALS SCIENCE↗
NASA NTRS2021

Strategies for the Design and Operation of Resilient Extraterrestrial Habitats

An Earth-independent permanent extraterrestrial habitat system must function as intended under continuous disruptive conditions, and with significantly limited Earth support and extended uncrewed periods. Designing for the demands that extreme environments such as wild temperature fluctuations, galactic cosmic rays, destructive dust, meteoroid impacts (direct or indirect), vibrations, and solar particle events, will place on long-term deep space habitats represents one of the greatest challenges in this endeavor. This context necessitates that we establish the know-how and technologies to build habitat systems that are resilient. Resilience is not simply robustness or redundancy: it is a system property that accounts for both anticipated and unanticipated disruptions via the design choices and maintenance processes, and adapts to them in operation. We currently lack the frameworks and technologies needed to achieve a high level of resilience in a habitat system. The Resilient Extra Terrestrial Habitats Institute (RETHi) has the mission of leveraging existing novel technologies to provide situational awareness and autonomy to enable the design of habitats that are able to adapt, absorb and rapidly recover from expected and unexpected disruptions. We are establishing both fully virtual and coupled physical-virtual simulation capabilities that will enable us to explore a wide range of potential deep space Smart Hab configurations and operating modes.

Space habitats↗
NASA NTRS2021

Strategies for the Design and Operation of Resilient Extraterrestrial Habitats

An Earth-independent permanent extraterrestrial habitat system must function as intended under continuous disruptive conditions, and with significantly limited Earth support and extended uncrewed periods. Designing for the demands that extreme environments such as wild temperature fluctuations, galactic cosmic rays, destructive dust, meteoroid impacts (direct or indirect), vibrations, and solar particle events, will place on long-term deep space habitats represents one of the greatest challenges in this endeavor. This context necessitates that we establish the know-how and technologies to build habitat systems that are resilient. Resilience is not simply robustness or redundancy: it is a system property that accounts for both anticipated and unanticipated disruptions via the design choices and maintenance processes and adapts to them in operation. We currently lack the frameworks and technologies needed to achieve a high level of resilience in a habitat system. The Resilient ExtraTerrestrial Habitats Institute (RETHi) has the mission of leveraging existing novel technologies to provide situational awareness and autonomy to enable the design of habitats that are able to adapt, absorb and rapidly recover from expected and unexpected disruptions. We are establishing both fully virtual and coupled physical-virtual simulation capabilities that will enable us to explore a wide range of potential deep space SmartHab configurations and operating modes.

Space habitats↗
NASA NTRS1985

Windvan laser study

The goal of defining a CO2 laser transmitter approach suited to Shuttle Coherent Atmospheric Lidar Experiment (SCALE) requirements is discussed. The adaptation of the existing WINDVAN system to the shuttle environment is addressed. The size, weight, reliability, and efficiency of the existing WINDVAN system are largely compatible with SCALE requirements. Repacking is needed for compatibility with vacuum and thermal environments. Changes are required to ensure survival through launch and landing, mechanical, vibration, and acoustic loads. Existing WINDVAN thermal management approaches depending on convection need to be upgraded zero gravity operations.

Source record↗
NASA NTRS1975

Review of measured vibration and noise environments experienced by passengers in aircraft and in ground transportation systems

Measured vibration and interior noise data are presented for a number of air and surface vehicles. Consideration is given to the importance of direction effects; of vehicle operations such as take-off, cruise, and landing; and of measurement location on the level and frequency of the measurements. Various physical measurement units or descriptors are used to quantify and compare the data. Results suggest the range of vibration and noise associated with a particular mode of transportation and illustrate the comparative levels in terms of each of the descriptors. Collectively, the results form a data base which may be useful in assessing the ride of existing or future systems relative to vehicles in current operation.

Stephens, D. G.↗
NASA NTRS2009

Microgravity Acceleration Measurement System

Microgravity Acceleration Measurement System (MAMS) is an ongoing study of the small forces (vibrations and accelerations) on the ISS that result from the operation of hardware, crew activities, as well as dockings and maneuvering. Results will be used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station to enable future research.

Foster, William↗
NASA NTRS2009

Space Acceleration Measurement System-II

Space Acceleration Measurement System (SAMS-II) is an ongoing study of the small forces (vibrations and accelerations) on the ISS that result from the operation of hardware, crew activities, as well as dockings and maneuvering. Results will be used to generalize the types of vibrations affecting vibration-sensitive experiments. Investigators seek to better understand the vibration environment on the space station to enable future research.

Foster, William↗
NASA NTRS2010

Configurable Multi-Purpose Processor

Advancements in technology have allowed the miniaturization of systems used in aerospace vehicles. This technology is driven by the need for next-generation systems that provide reliable, responsive, and cost-effective range operations while providing increased capabilities such as simultaneous mission support, increased launch trajectories, improved launch, and landing opportunities, etc. Leveraging the newest technologies, the command and telemetry processor (CTP) concept provides for a compact, flexible, and integrated solution for flight command and telemetry systems and range systems. The CTP is a relatively small circuit board that serves as a processing platform for high dynamic, high vibration environments. The CTP can be reconfigured and reprogrammed, allowing it to be adapted for many different applications. The design is centered around a configurable field-programmable gate array (FPGA) device that contains numerous logic cells that can be used to implement traditional integrated circuits. The FPGA contains two PowerPC processors running the Vx-Works real-time operating system and are used to execute software programs specific to each application. The CTP was designed and developed specifically to provide telemetry functions; namely, the command processing, telemetry processing, and GPS metric tracking of a flight vehicle. However, it can be used as a general-purpose processor board to perform numerous functions implemented in either hardware or software using the FPGA s processors and/or logic cells. Functionally, the CTP was designed for range safety applications where it would ultimately become part of a vehicle s flight termination system. Consequently, the major functions of the CTP are to perform the forward link command processing, GPS metric tracking, return link telemetry data processing, error detection and correction, data encryption/ decryption, and initiate flight termination action commands. Also, the CTP had to be designed to survive and operate in a launch environment. Additionally, the CTP was designed to interface with the WFF (Wallops Flight Facility) custom-designed transceiver board which is used in the Low Cost TDRSS Transceiver (LCT2) also developed by WFF. The LCT2 s transceiver board demodulates commands received from the ground via the forward link and sends them to the CTP, where they are processed. The CTP inputs and processes data from the inertial measurement unit (IMU) and the GPS receiver board, generates status data, and then sends the data to the transceiver board where it is modulated and sent to the ground via the return link. Overall, the CTP has combined processing with the ability to interface to a GPS receiver, an IMU, and a pulse code modulation (PCM) communication link, while providing the capability to support common interfaces including Ethernet and serial interfaces boarding a relatively small-sized, lightweight package.

Valencia, J. Emilio↗
NASA NTRS1979

Laser-optical blade tip clearance measurement system

A laser-optical measurement system was developed to measure single blade tip clearances and average blade tip clearances between a rotor and its gas path seal in rotating component rigs and complete engines. The system is applicable to fan, compressor and turbine blade tip clearance measurements. The engine mounted probe is particularly suitable for operation in the extreme turbine environment. The measurement system consists of an optical subsystem, an electronic subsystem and a computing and graphic terminal. Bench tests and environmental tests were conducted to confirm operation at temperatures, pressures, and vibration levels typically encountered in an operating gas turbine engine.

Barranger, J. P.↗