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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 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Towards a Generic and Adaptive System-On-Chip Controller for Space Exploration Instrumentation

This paper introduces one of the first efforts conducted at NASA’s Jet Propulsion Laboratory (JPL) to develop a generic System-on-Chip (SoC) platform to control science instruments that are proposed for future NASA missions. The SoC platform is named APEX-SoC, where APEX stands for Advanced Processor for space Exploration, and is based on a hybrid Xilinx Zynq that combines an FPGA and an ARM Cortex-A9 dual-core processor on a single chip. The Zynq implements a generic and customizable on-chip infrastructure that can be reused with a variety of instruments, and it has been coupled with a set of off-chip components that are necessary to deal with the different instruments. We have taken JPL’s Compositional InfraRed Imaging Spectrometer (CIRIS), which is proposed for NASA icy moons missions, as a use-case scenario to demonstrate that the entire data processing, control and interface of an instrument can be implemented on a single device using the on-chip infrastructure described in this paper. We show that the performance results achieved in this preliminary version of the instrumentation controller are sufficient to fulfill the science requirements demanded to the CIRIS instrument in future NASA missions, such as Europa.

embedded system↗
NASA NTRS2003

Mechanical counter pressure on the arm counteracts adverse effects of hypobaric exposures

INTRODUCTION: Current space suits have limited movement due to gas pressurization during exposure to the vacuum of space. Alternatively, if pressure is applied by an elastic garment vs. pneumatic garment to produce mechanical counter pressure (MCP), several advantages are possible. In this study, we investigate local microcirculatory and other effects produced with and without a prototype MCP glove and sleeve during exposure to varying levels of vacuum. METHODS: The entire arms of eight male volunteers were studied at normal ambient pressure and during 5 min exposures to -50, -100, and -150 mm Hg with and without the MCP glove and sleeve. Pressure distribution, skin microvascular flow, and temperature were measured. RESULTS: The MCP glove and sleeve generated over 200 mm Hg on the middle finger, dorsum of the hand, and the wrist. However, pressure was significantly lower on the forearm and the upper arm. Without the glove and sleeve, only two of eight subjects tolerated -100 mm Hg. Also, no subject tolerated -150 mm Hg. However, subjects tolerated all vacuum pressures wearing the glove and sleeve. Skin microvascular flow and temperature remained within control values with the glove and sleeve at a chamber pressure of -150 mm Hg. DISCUSSION: The MCP glove and sleeve counteracts adverse effects of vacuum exposures due to lower pressure differentials. Pressure levels over the hand and wrist are similar to those of the current U.S. space suit glove and sleeve, but additional development is required to increase MCP over the forearm and upper arm.

NASA Discipline Cardiopulmonary↗
NASA NTRS1982

Control system design for the large space systems technology reference platform

Structural models and classical frequency domain control system designs were developed for the large space systems technology (LSST) reference platform which consists of a central bus structure, solar panels, and platform arms on which a variety of experiments may be mounted. It is shown that operation of multiple independently articulated payloads on a single platform presents major problems when subarc second pointing stability is required. Experiment compatibility will be an important operational consideration for systems of this type.

Edmunds, R. S.↗
NASA NTRS1988

Robots for manipulation in a micro-gravity environment

This paper is concerned with the development of control strategies and mechanisms for robots operating in the micro-gravity environment of Space Station. These robots must be capable of conducting experiments and manufacturing processes without disturbing the micro-gravity environment through base reactions/motions. Approaches discussed for controlling the robot base reactions/motions include strategies making use of manipulators with redundant degrees of freedon, actuators at the robot base, and a redundant (balancing) arm. Two degree-of-freedom, traction-drive joints are discussed as well as the conceptual design for a traction-driven manipulator.

Quinn, R. D.↗
NASA NTRS1991

Testbed For Telerobotic Servicing

Telerobot testbed used to evaluate technologies for remote servicing, including assembly, maintenance, and repair. Enables study of advantages and disadvantages of modes and problems encountered in implementing them. Best technologies for implementing modes chosen. Provides delays simulating transmission delays between control stations on ground and orbiting spacecraft. Includes five major equipment subsystems, each consisting of such commercially available equipment as video cameras, computers, and robot arms. Used on Space Station and on Space Shuttle and satellites in orbit. Also used in hazardous and underwater environments on Earth.

Matijevic, Jacob R.↗
NASA NTRS1992

Orbital Welding Head Held By Robot

Orbital welding head positioned by robot controls motion and voltage of arc-welding torch mounted in head. New head encircles part at torch end, and held and manipulated by robot arm at opposite end. Entire welding operation automated. Useful for operations in hazardous environments.

Gangl, Kenneth J.↗
NASA NTRS1993

The influence of a microgravity environment on the dendritic morphology during directional solidification of hypoeutectic Al-Si alloys

NASA grant NAGW-2540 provided the opportunity to evaluate and extend ongoing studies of directionally solidified Al-Si alloys. Microstructural development was further characterized in terms of solidification processing parameters; novel relationships between processing and development of dendrite trunk diameters and tertiary dendrite arm spacings were found. This has resulted in three publications (one in print, one in press, and one in review). Microstructural development under conditions of controlled acceleration during directional solidification has been investigated; this has culminated in a Master's degree and will be submitted for publication. The above work not only contributes to our understanding of solidification phenomena but also defines the processing parameters for a successful microgravity experiment while providing a data base to which mu g samples can be unequivocally compared and evaluated.

Grugel, Richard N.↗
NASA NTRS2013

SequenceL: Automated Parallel Algorithms Derived from CSP-NT Computational Laws

With the introduction of new parallel architectures like the cell and multicore chips from IBM, Intel, AMD, and ARM, as well as the petascale processing available for highend computing, a larger number of programmers will need to write parallel codes. Adding the parallel control structure to the sequence, selection, and iterative control constructs increases the complexity of code development, which often results in increased development costs and decreased reliability. SequenceL is a high-level programming language that is, a programming language that is closer to a human s way of thinking than to a machine s. Historically, high-level languages have resulted in decreased development costs and increased reliability, at the expense of performance. In recent applications at JSC and in industry, SequenceL has demonstrated the usual advantages of high-level programming in terms of low cost and high reliability. SequenceL programs, however, have run at speeds typically comparable with, and in many cases faster than, their counterparts written in C and C++ when run on single-core processors. Moreover, SequenceL is able to generate parallel executables automatically for multicore hardware, gaining parallel speedups without any extra effort from the programmer beyond what is required to write the sequen tial/singlecore code. A SequenceL-to-C++ translator has been developed that automatically renders readable multithreaded C++ from a combination of a SequenceL program and sample data input. The SequenceL language is based on two fundamental computational laws, Consume-Simplify- Produce (CSP) and Normalize-Trans - pose (NT), which enable it to automate the creation of parallel algorithms from high-level code that has no annotations of parallelism whatsoever. In our anecdotal experience, SequenceL development has been in every case less costly than development of the same algorithm in sequential (that is, single-core, single process) C or C++, and an order of magnitude less costly than development of comparable parallel code. Moreover, SequenceL not only automatically parallelizes the code, but since it is based on CSP-NT, it is provably race free, thus eliminating the largest quality challenge the parallelized software developer faces.

Cooke, Daniel↗
DOE OSTI2021

Radio frequency passband signal generation using photonics

Devices, methods and systems for generating wideband, high-fidelity arbitrary radio frequency (RF) passband signals are described. A voltage tunable optical filter for arbitrary RF passband signal generation includes a first input configured to receive a broadband optical pulse train, a second input configured to receive a first control voltage representative of an amplitude signal, an electrooptic modulator to receive the broadband optical pulse train and the first control voltage, to modulate the broadband optical pulse train in accordance with the amplitude signal, and to produce two complementary optical outputs that form two arms of an interferometer, an optical delay component to impart an optical path difference into one of the complementary outputs of the electrooptic modulator, and a combiner or a splitter to receive two complementary optical outputs of the electrooptic modulator after impartation of the optical path difference and to produce an output interference pattern of fringes.

Gowda, Apurva Shantharaj↗
DOE OSTI2023

Radio frequency passband signal generation using photonics

Devices, methods and systems for generating wideband, high-fidelity arbitrary radio frequency (RF) passband signals are described. A voltage tunable optical filter for arbitrary RF passband signal generation includes a first input configured to receive a broadband optical pulse train, a second input configured to receive a first control voltage representative of an amplitude signal, an electrooptic modulator to receive the broadband optical pulse train and the first control voltage, to modulate the broadband optical pulse train in accordance with the amplitude signal, and to produce two complementary optical outputs that form two arms of an interferometer, an optical delay component to impart an optical path difference into one of the complementary outputs of the electrooptic modulator, and a combiner or a splitter to receive two complementary optical outputs of the electrooptic modulator after impartation of the optical path difference and to produce an output interference pattern of fringes.

Gowda, Apurva Shantharaj↗
NASA NTRS1990

Static Wind-Tunnel and Radio-Controlled Flight Test Investigation of a Remotely Piloted Vehicle Having a Delta Wing Planform

At the request of the United States Marine Corps, an exploratory wind-tunnel and flight test investigation was conducted by the Flight Dynamics Branch at the NASA Langley Research Center to improve the stability, controllability, and general flight characteristics of the Marine Corps Exdrone RPV (Remotely Piloted Vehicle) configuration. Static wind tunnel tests were conducted in the Langley 12 foot Low Speed Wind Tunnel to identify and improve the stability and control characteristics of the vehicle. The wind tunnel test resulted in several configuration modifications which included increased elevator size, increased vertical tail size and tail moment arm, increased rudder size and aileron size, the addition of vertical wing tip fins, and the addition of leading-edge droops on the outboard wing panel to improve stall departure resistance. Flight tests of the modified configuration were conducted at the NASA Plum Tree Test Site to provide a qualitative evaluation of the flight characteristics of the modified configuration.

Yip, Long P.↗
NASA NTRS1990

Wind-tunnel and flight-test investigation of the exdrone remotely piloted vehicle configuration

At the request of the United States Marine Corps, an exploratory wind-tunnel and flight test investigation was conducted by the NASA Langley Research Center to improve the stability, controllability, and general flight characteristics of the Marine Corps Exdrone RPV (Remotely Piloted Vehicle) configuration. Static wind tunnel tests were conducted to identify and improve the stability and control characteristics of the vehicle. The wind-tunnel test resulted in several configuration modifications which included increased elevator area, increased vertical tail area and moment arm, increased rudder area and aileron area, the addition of vertical wing-tip fins, and the addition of leading-edge droops on the outboard wing panel to improve the stall departure resistance. Flight tests of the modified configuration were conducted at the NASA Plum Tree Test Site to provide a qualitative evaluation of the flight characteristics of the modified configuration.

Yip, Long P.↗
NASA NTRS1991

Performance capabilities of a JPL dual-arm advanced teleoperation system

The system comprises: (1) two PUMA 560 robot arms, each equipped with the latest JPL developed smart hands which contain 3-D force/moment and grasp force sensors; (2) two general purpose force reflecting hand controllers; (3) a NS32016 microprocessors based distributed computing system together with JPL developed universal motor controllers; (4) graphics display of sensor data; (5) capabilities for time delay experiments; and (6) automatic data recording capabilities. Several different types of control modes are implemented on this system using different feedback control techniques. Some of the control modes and the related feedback control techniques are described, and the achievable control performance for tracking position and force trajectories are reported. The interaction between position and force trajectory tracking is illustrated. The best performance is obtained by using a novel, task space error feedback technique.

Szakaly, Z. F.↗
NASA NTRS1992

Open-Loop Acquisition Of Frequency In BPSK

Proposed open-loop analog/digital signal-processing system would be Costas-loop error detector functioning in closed-loop manner overall. Detector estimates difference between frequency of input signal and internal reference oscillator. Estimate used to close frequency-control loop. Precise symbol timing not necessary. Performance better than systems that effect open-loop acquisition using integrators instead of low-pass filters in arms of Costas loops and in which performance varies with symbol timing.

Shah, Biren N.↗
NASA NTRS2005

Vision and "Hand-Eye" Coordination for the Fujitsu HOAP-2 Humanoid Robot

Software was developed for a Fujitsu HOAP-2 humanoid robot to demonstrate that such "human form" robots can be used to perform useful tasks in an unknown environment; specifically, that they can operate with or in the place of humans to carry out construction operations necessary for space exploration, such as building or maintaining planetary surface habitats for humans. This paper describes the autonomous vision and hand-eye coordination software that enables the HOAP-2 to locate and manipulate objects. Simple vision and pattern detection algorithms including color filtering, noise filtering, image segmentation, orientation filters, and a feedback controlled tracking system enable the robot to locate marked building materials in the workspace. Experimentally determined spatial mappings associate locations in the visual field with the arm joint angles and trajectories necessary to reach these locations, allowing the robot to reach for and manipulate the building materials. These capabilities, when combined with locomotion capabilities, enable the robot to operate autonomously in an unknown workspace.

Moore, Jeffrey D.↗
NASA NTRS2012

Analysis of the Touch-And-Go Surface Sampling Concept for Comet Sample Return Missions

This paper studies the Touch-and-Go (TAG) concept for enabling a spacecraft to take a sample from the surface of a small primitive body, such as an asteroid or comet. The idea behind the TAG concept is to let the spacecraft descend to the surface, make contact with the surface for several seconds, and then ascend to a safe location. Sampling would be accomplished by an end-effector that is active during the few seconds of surface contact. The TAG event is one of the most critical events in a primitive body sample-return mission. The purpose of this study is to evaluate the dynamic behavior of a representative spacecraft during the TAG event, i.e., immediately prior, during, and after surface contact of the sampler. The study evaluates the sample-collection performance of the proposed sampling end-effector, in this case a brushwheel sampler, while acquiring material from the surface during the contact. A main result of the study is a guidance and control (G&C) validation of the overall TAG concept, in addition to specific contributions to demonstrating the effectiveness of using nonlinear clutch mechanisms in the sampling arm joints, and increasing the length of the sampling arms to improve robustness.

Touch-and-Go (TAG)↗
NASA NTRS2002

Spatial learning and memory is preserved in rats after early development in a microgravity environment

This study evaluated the cognitive mapping abilities of rats that spent part of their early development in a microgravity environment. Litters of male and female Sprague-Dawley rat pups were launched into space aboard the National Aeronautics and Space Administration space shuttle Columbia on postnatal day 8 or 14 and remained in space for 16 days. These animals were designated as FLT groups. Two age-matched control groups remained on Earth: those in standard vivarium housing (VIV) and those in housing identical to that aboard the shuttle (AGC). On return to Earth, animals were tested in three different tasks that measure spatial learning ability, the Morris water maze (MWM), and a modified version of the radial arm maze (RAM). Animals were also tested in an open field apparatus to measure general activity and exploratory activity. Performance and search strategies were evaluated in each of these tasks using an automated tracking system. Despite the dramatic differences in early experience, there were remarkably few differences between the FLT groups and their Earth-bound controls in these tasks. FLT animals learned the MWM and RAM as quickly as did controls. Evaluation of search patterns suggested subtle differences in patterns of exploration and in the strategies used to solve the tasks during the first few days of testing, but these differences normalized rapidly. Together, these data suggest that development in an environment without gravity has minimal long-term impact on spatial learning and memory abilities. Any differences due to development in microgravity are quickly reversed after return to earth normal gravity.

NASA Discipline Neuroscience↗