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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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161 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

The modern high rate digital cassette recorder

The magnetic tape recorder has played an essential role in the capture and storage of instrumentation data for more than thirty years. During this time, data recording technology has steadily progressed to meet user demands for more channels, wider bandwidths, and longer recording durations. When acquisition and processing moved from analog to digital techniques, so recorder design followed suit. Milestones marking the evolution of the data recorder through these various stages - multi-track analog, high density longitudinal digital, and more recently rotary digital - have often represented important breakthroughs in the handling of ever-greater quantities of data. Throughout this period there has been a very clear line of demarcation between data storage methods in the 'instrumentation world' on the one hand and the 'computer peripheral world' on the other. This is despite the fact that instrumentation data, whether analog or digital at the point of acquisition, is now likely to be processed on a digital computer at some stage. Regardless of whether the processing device is a small personal computer, a workstation, or the largest supercomputer, system integrators have traditionally been faced with the same basic problem - how to interface what is essentially a manually controlled, continuously running device (the tape recorder) into the fast start/stop computer environment without resorting to an excessive amount of complex custom interfacing and performance compromise. The increasing availability of affordable high power processing equipment throughout the scientific world is forcing recorder manufacturers to make their latest and perhaps most important breakthrough - the computer-friendly data recorder. The operating characteristics of such recorders are discussed and the resultant impact on both data acquisition and data analysis elements of system configuration are considered.

Clemow, Martin↗
NASA NTRS2002

Engine balance apparatus and accessory drive device

A balancing mechanism for an engine that has a rotating crankshaft and reciprocating pistons. The balancing mechanism comprises a primary balance mass assembly non-rotatably and removably affixed to the crankshaft. The primary mass assembly comprises a primary mass affixed to a primary hub portion and a primary cap portion removably affixed to the primary hub portion to clamp a portion of the crankshaft therebetween. A secondary balance mass assembly may be rotatably and removably supported on the crankshaft. A driver assembly is affixed to the crankshaft to cause the secondary balance mass to rotate in a direction that is opposite to the direction in which the crank shaft is rotating. The driver assembly may include auxiliary gears configured to transport rotary power to auxiliary components. The gears are readily detachable from the apparatus to facilitate inspection and repair operations.

Egleston, Robert W.↗
NASA NTRS2005

Absolute Position Encoders With Vertical Image Binning

Improved optoelectronic patternrecognition encoders that measure rotary and linear 1-dimensional positions at conversion rates (numbers of readings per unit time) exceeding 20 kHz have been invented. Heretofore, optoelectronic pattern-recognition absoluteposition encoders have been limited to conversion rates <15 Hz -- too low for emerging industrial applications in which conversion rates ranging from 1 kHz to as much as 100 kHz are required. The high conversion rates of the improved encoders are made possible, in part, by use of vertically compressible or binnable (as described below) scale patterns in combination with modified readout sequences of the image sensors [charge-coupled devices (CCDs)] used to read the scale patterns. The modified readout sequences and the processing of the images thus read out are amenable to implementation by use of modern, high-speed, ultra-compact microprocessors and digital signal processors or field-programmable gate arrays. This combination of improvements makes it possible to greatly increase conversion rates through substantial reductions in all three components of conversion time: exposure time, image-readout time, and image-processing time.

Leviton, Douglas B.↗
NASA NTRS2012

Drilling, Coring and Sampling Using Piezoelectric Actuated Mechanisms: From the USDC to a Piezo-Rotary-Hammer Drill

NASA exploration missions are increasingly including sampling tasks but with the growth in engineering experience (particularly, Phoenix Scout and MSL) it is now very much recognized that planetary drilling poses many challenges. The difficulties grow significantly with the hardness of sampled material, the depth of drilling and the harshness of the environmental conditions. To address the requirements for samplers that could be operated at the conditions of the various bodies in the solar system, a number of piezoelectric actuated drills and corers were developed by the Advanced Technologies Group of JPL. The basic configuration that was conceived in 1998 is known as the Ultrasonic/Sonic Driller/Corer (USDC), and it operates as a percussive mechanism. This drill requires as low preload as 10N (important for operation at low gravity) allowing to operate with as low-mass device as 400g, use an average power as low as 2- 3W and drill rocks as hard as basalt. A key feature of this drilling mechanism is the use of a free-mass to convert the ultrasonic vibrations generated by piezoelectric stack to sonic impacts on the bit. Using the versatile capabilities f the USDC led to the development of many configurations and device sizes. Significant improvement of the penetration rate was achieved by augmenting the hammering action by rotation and use of a fluted bit to remove cuttings. To reach meters deep in ice a wireline drill was developed called the Ultrasonic/Sonic Gopher and it was demonstrated in 2005 to penetrate about 2-m deep at Antarctica. Jointly with Honeybee Robotics, this mechanism is currently being modified to incorporate rotation and inchworm operation forming Auto-Gopher to reach meters deep in rocks. To take advantage of the ability of piezoelectric actuators to operate over a wide temperatures range, piezoelectric actuated drills were developed and demonstrated to operate at as cold as -200oC and as hot as 500oC. In this paper, the developed mechanisms will be reviewed and discussed including the configurations, capabilities, and challenges.

ultrasonic/Sonic Driller/ Corer (USDC)↗
NASA NTRS2012

Actuation Using Piezoelectric Materials: Application in Augmenters, Energy Harvesters, and Motors

Piezoelectric actuators are used in many manipulation, movement, and mobility applications as well as transducers and sensors. When used at the resonance frequencies of the piezoelectric stack, the actuator performs at its maximum actuation capability. In this Space Grant internship, three applications of piezoelectric actuators were investigated including hammering augmenters of rotary drills, energy harvesters, and piezo-motors. The augmenter shows improved drill performance over rotation only. The energy harvesters rely on moving fluid to convert mechanical energy into electrical power. Specific designs allow the harvesters more freedom to move, which creates more power. The motor uses the linear movement of the actuator with a horn applied to the side of a rotor to create rotational motion. Friction inhibits this motion and is to be minimized for best performance. Tests and measurements were made during this internship to determine the requirements for optimal performance of the studied mechanisms and devices.

drills↗
NASA NTRS1989

Superfluid Helium Orbital Resupply Coupling

The resupply of superfluid helium to satellites and other space-based experiment packages can increase the useful longevity of these devices far beyond their present life expectancies which are many times determined by the supply of helium coolant. The transfer of superfluid helium to spacecraft in space will require a reusable coupling that functions at 1.8 Kelvin with little heat leak and low pressure drop. Moog has designed the Helium Resupply Coupling to meet these operational requirements. Initially, the coupling manual mode operation will be demonstrated on orbit by an EVA crew member during the Space Shuttle borne Superfluid Helium On-Orbit Transfer (SHOOT) experiment. The ultimate application will use robotic (automatic) coupling operation to which the present design readily adapts. The utilization of Moog's exclusive Rotary Shut-Off (RSO) technology in the development of the Superfluid Helium Resupply Coupling is described. The coupling not only performs the function of a flow control valve and disconnect but also provides adequate safety features for a shuttle launched man-rated payload. In addition, the coupling incorporates the necessary features to provide the high thermal isolation of the internal flow path from the external environment.

Ryder, M. O.↗
NASA NTRS2008

Vertical Drop Testing and Analysis of the WASP Helicopter Skid Gear

Human occupant modeling and injury risk assessment have been identified as areas of research for improved prediction of rotorcraft crashworthiness within the NASA Aeronautics Program's Subsonic Rotary Wing Project. As part of this effort, an experimental program was conducted to assess the impact performance of a skid gear for use on the WASP kit-built helicopter, which is marketed by HeloWerks, Inc. of Hampton, Virginia. Test data from a drop test at an impact velocity of 8.4 feet-per-second were used to assess a finite element model of the skid gear test article. This assessment included human occupant analytic models developed for execution in LS-DYNA. The test article consisted of an aluminum skid gear mounted beneath a steel plate. A seating platform was attached to the upper surface of the steel plate, and two 95th percentile Hybrid III male Aerospace Anthropomorphic Test Devices (ATDs) were seated on the platform and secured using a four-point restraint system. The goal of the test-analysis correlation is to further the understanding of LS-DYNA ATD occupant models and responses in the vertical (or spinal) direction. By correlating human occupant experimental test data for a purely vertical impact with the LS-DYNA occupant responses, improved confidence in the use of these tools and better understanding of the limitations of the automotive-based occupant models for aerospace application can begin to be developed.

Fuchs, Yvonne T.↗
NASA NTRS2008

Vertical Drop Testing and Analysis of the WASP Helicopter Skid Gear

Human occupant modeling and injury risk assessment have been identified as areas of research for improved prediction of rotorcraft crashworthiness within the NASA Aeronautics Program s Subsonic Rotary Wing Project. As part of this effort, an experimental program was conducted to assess the impact performance of a skid gear for use on the WASP kit-built helicopter, which is marketed by HeloWerks, Inc. of Hampton, Virginia. Test data from a drop test at an impact velocity of 8.4 feet-per-second were used to assess a finite element model of the skid gear test article. This assessment included human occupant analytic models developed for execution in LS-DYNA. The test article consisted of an aluminum skid gear mounted beneath a steel plate. A seating platform was attached to the upper surface of the steel plate, and two 95th percentile Hybrid III male Aerospace Anthropomorphic Test Devices (ATDs) were seated on the platform and secured using a four-point restraint system. The goal of the test-analysis correlation is to further the understanding of LS-DYNA ATD occupant models and responses in the vertical (or spinal) direction. By correlating human occupant experimental test data for a purely vertical impact with the LS-DYNA occupant responses, improved confidence in the use of these tools and better understanding of the limitations of the automotive-based occupant models for aerospace application can begin to be developed.

Fuchs, Yvonne T.↗
NASA NTRS1994

Vertical flight training: An overview of training and flight simulator technology with emphasis on rotary-wing requirements

The principal purpose of this publication is to provide a broad overview of the technology that is relevant to the design of aviation training systems and of the techniques applicable to the development, use, and evaluation of those systems. The issues addressed in our 11 chapters are, for the most part, those that would be expected to surface in any informed discussion of the major characterizing elements of aviation training systems. Indeed, many of the same facets of vertical-flight training discussed were recognized and, to some extent, dealt with at the 1991 NASA/FAA Helicopter Simulator Workshop. These generic topics are essential to a sound understanding of training and training systems, and they quite properly form the basis of any attempt to systematize the development and evaluation of more effective, more efficient, more productive, and more economical approaches to aircrew training. Individual chapters address the following topics: an overview of the vertical flight industry: the source of training requirements; training and training schools: meeting current requirements; training systems design and development; transfer of training and cost-effectiveness; the military quest for flight training effectiveness; alternative training systems; training device manufacturing; simulator aero model implementation; simulation validation in the frequency domain; cockpit motion in helicopter simulation; and visual space perception in flight simulators.

Alderete, Thomas S.↗
NASA NTRS2013

Acoustic Mechanical Feedthroughs

Electromagnetic motors can have problems when operating in extreme environments. In addition, if one needs to do mechanical work outside a structure, electrical feedthroughs are required to transport the electric power to drive the motor. In this paper, we present designs for driving rotary and linear motors by pumping stress waves across a structure or barrier. We accomplish this by designing a piezoelectric actuator on one side of the structure and a resonance structure that is matched to the piezoelectric resonance of the actuator on the other side. Typically, piezoelectric motors can be designed with high torques and lower speeds without the need for gears. One can also use other actuation materials such as electrostrictive, or magnetostrictive materials in a benign environment and transmit the power in acoustic form as a stress wave and actuate mechanisms that are external to the benign environment. This technology removes the need to perforate a structure and allows work to be done directly on the other side of a structure without the use of electrical feedthroughs, which can weaken the structure, pipe, or vessel. Acoustic energy is pumped as a stress wave at a set frequency or range of frequencies to produce rotary or linear motion in a structure. This method of transferring useful mechanical work across solid barriers by pumping acoustic energy through a resonant structure features the ability to transfer work (rotary or linear motion) across pressure or thermal barriers, or in a sterile environment, without generating contaminants. Reflectors in the wall of barriers can be designed to enhance the efficiency of the energy/power transmission. The method features the ability to produce a bi-directional driving mechanism using higher-mode resonances. There are a variety of applications where the presence of a motor is complicated by thermal or chemical environments that would be hostile to the motor components and reduce life and, in some instances, not be feasible. A variety of designs that have been designed, fabricated and tested will be presented

piezoelectric devices↗
NASA NTRS1991

Dead-blow hammer design applied to a calibration target mechanism to dampen excessive rebound

An existing rotary electromagnetic driver was specified to be used to deploy and restow a blackbody calibration target inside of a spacecraft infrared science instrument. However, this target was much more massive than any other previously inherited design applications. The target experienced unacceptable bounce when reaching its stops. Without any design modification, the momentum generated by the driver caused the target to bounce back to its starting position. Initially, elastomeric dampers were used between the driver and the target. However, this design could not prevent the bounce, and it compromised the positional accuracy of the calibration target. A design that successfully met all the requirements incorporated a sealed pocket 85 percent full of 0.75 mm diameter stainless steel balls in the back of the target to provide the effect of a dead-blow hammer. The energy dissipation resulting from the collision of balls in the pocket successfully dampened the excess momentum generated during the target deployment. The disastrous effects of new requirements on a design with a successful flight history, the modifications that were necessary to make the device work, and the tests performed to verify its functionality are described.

Lim, Brian Y.↗
NASA NTRS2010

Spontaneous Raman Scattering Diagnostics: Applications in Practical Combustion Systems

In this chapter, the recent advancements and practical aspects of laser SRS diagnostics have been reviewed wi til regards to applications in practical combustion systems. Clearly, SRS represents a theoretically and experimentally mature diagnostic technology that has become an essential tool for multiscalar measurements in turbulent combustion at elevated pressures. Today, time-, space-, spectrally, and even polarization-resolved S RS diagnostics is at hand, with aid from recent innovations in theoretical and technological developments on electro-optical or electromechanical devices. Whilst a linear increase in SRS signals can be expected in high-pressure systems (this is perhaps one of the most important advantages for using SRS in high-pressure systems), there are practical (often severe) restrictions associated with pressurized vessels, due mainly to the limited degree of optical access. This narrows ti,e available choice of diagnostics that can be employed at any given time. Point-wise SRS diagnostics provides the highest accuracy on the chemical species and temperature measurements, and will continue to remain a vital approach for the study in such harsh environments. The practical design considerations and hands-on set-up guide for SRS diagnostics provided in this chapter are rarely presented elsewhere. Although the second-harmonic Nd:YAG pulsed laser (532 nm), combined with pulse-stretching optics or the recently introduced White Cell-based laser, seems to be the most favored excitation source of choice by the research community, UV excitation will undoubtedly continue to be used on many occasions, and especially in sooting flames. Detection methods may be divided into ICCD-based nanosecond-gate detection or a rotary-chopper electromechanical shutter-based CCD array detection, and the levels of background flame emission in individual cases would determine this critical design choice. Here, a process of Raman signal calibration based on ti,e crosstalk matrix formalism was explained step-by-step. As tI,is process may be very time-consuming and expensive, a well-planned experimental approach (01' building a transferable calibration database or library (at least with in a user's own facility over a series of different testing and runs) is vitally important. Hands on advice on the design and construction of flow control systems for high pressure burner facilities were also presented.

Kojima, Jun↗
NASA NTRS1999

Induction of three-dimensional assembly of human liver cells by simulated microgravity

The establishment of long-term cultures of functional primary human liver cells (PHLC) is formidable. Developed at NASA, the Rotary Cell Culture System (RCCS) allows the creation of the unique microgravity environment of low shear force, high-mass transfer, and 3-dimensional cell culture of dissimilar cell types. The aim of our study was to establish long-term hepatocyte cultures in simulated microgravity. PHLC were harvested from human livers by collagenase perfusion and were cultured in RCCS. PHLC aggregates were readily formed and increased up to 1 cm long. The expansion of PHLC in bioreactors was further evaluated with microcarriers and biodegradable scaffolds. While microcarriers were not conducive to formation of spheroids, PHLC cultured with biodegradable scaffolds formed aggregates up to 3 cm long. Analyses of PHLC spheroids revealed tissue-like structures composed of hepatocytes, biliary epithelial cells, and/or progenitor liver cells that were arranged as bile duct-like structures along nascent vascular sprouts. Electron microscopy revealed groups of cohesive hepatocytes surrounded by complex stromal structures and reticulin fibers, bile canaliculi with multiple microvilli, and tight cellular junctions. Albumin mRNA was expressed throughout the 60-d culture. A simulated microgravity environment is conducive to maintaining long-term cultures of functional hepatocytes. This model system will assist in developing improved protocols for autologous hepatocyte transplantation, gene therapy, and liver assist devices, and facilitate studies of liver regeneration and cell-to-cell interactions that occur in vivo.

NASA Center JSC↗
NASA NTRS2013

Cobra Fiber-Optic Positioner Upgrade

A prime focus spectrometer (PFS), along with corrective optics, will mount in place of the secondary mirror of the Subaru telescope on Mauna Kea, Hawaii. This will allow simultaneous observations of cosmologic targets. It will enable large-scale galactic archeology and dark energy surveys to help unlock the secrets of the universe. To perform these cosmologic surveys, an array of 2,400 optical fibers needs to be independently positioned within the 498-mm-diameter focal plane of the PFS instrument to collect light from galaxies and stars for spectrographic analyses. To allow for independent re-positioning of the fibers, a very small positioner (7.7 mm in diameter) is required. One hundred percent coverage of the focal plane is also required, so these small actuators need to cover a patrol region of 9.5 mm in diameter. To optimize the amount of light that can be collected, the fibers need to be placed within 5 micrometers of their intended target (either a star or galaxy). The Cobra Fiber Positioner was designed to meet the size and accuracy requirements stated above. Cobra is a two-degrees-of-freedom mechanism that can position an optical fiber in the focal plane of the PFS instrument to a precision of 5 micrometers. It is a theta-phi style positioner containing two rotary piezo tube motors with one offset from the other, which enables the optic fibers to be placed anywhere in a small circular patrol region. The patrol region of the actuator is such that the array of 2,400 positioners allows for full coverage of the instrument focal plane by overlapping the patrol areas. A second-generation Cobra positioner was designed based on lessons learned from the original prototype built in 2009. Improvements were made to the precision of the ceramic motor parts, and hard stops were redesigned to minimize friction and prevent jamming. These changes resulted in reducing the number of move iterations required to position the optical fiber within 5 micrometers of its target. At the time of this reporting, there are still many tests to be performed that will validate system level performance, but on an individual level, the Cobra positioner demonstrates excellent performance and will enable the PFS instrument to make unprecedented measurements of the universe. What is unique about the upgrades made to the Cobra positioner is the improved performance due to the design changes in the hard stops and the ceramic end caps of the motors. Other changes were made to reduce the unit cost of a Cobra positioner without affecting the performance, since thousands of these devices will have to be built for the PFS instrument.

Fisher, Charles D.↗
NASA NTRS2014

Evaluation of the First Transport Rotorcraft Airframe Crash Testbed (TRACT 1) Full-Scale Crash Test

In 2012, the NASA Rotary Wing Crashworthiness Program initiated the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program by obtaining two CH-46E helicopters from the Navy CH-46E Program Office (PMA-226) at the Navy Flight Readiness Center in Cherry Point, North Carolina. Full-scale crash tests were planned to assess dynamic responses of transport-category rotorcraft under combined horizontal and vertical impact loading. The first crash test (TRACT 1) was performed at NASA Langley Research Center's Landing and Impact Research Facility (LandIR), which enables the study of critical interactions between the airframe, seat, and occupant during a controlled crash environment. The CH-46E fuselage is categorized as a medium-lift rotorcraft with fuselage dimensions comparable to a regional jet or business jet. The first TRACT test (TRACT 1) was conducted in August 2013. The primary objectives for TRACT 1 were to: (1) assess improvements to occupant loads and displacement with the use of crashworthy features such as pre-tensioning active restraints and energy absorbing seats, (2) develop novel techniques for photogrammetric data acquisition to measure occupant and airframe kinematics, and (3) provide baseline data for future comparison with a retrofitted airframe configuration. Crash test conditions for TRACT 1 were 33-ft/s forward and 25-ft/s vertical combined velocity onto soft soil, which represent a severe, but potentially survivable impact scenario. The extraordinary value of the TRACT 1 test was reflected by the breadth of meaningful experiments. A total of 8 unique experiments were conducted to evaluate ATD responses, seat and restraint performance, cargo restraint effectiveness, patient litter behavior, and photogrammetric techniques. A combination of Hybrid II, Hybrid III, and ES-2 Anthropomorphic Test Devices (ATDs) were placed in forward and side facing seats and occupant results were compared against injury criteria. Loads from ATDs in energy absorbing seats and restraints were within injury limits. Severe injury was likely for ATDs in forward facing passenger seats, legacy troop bench seats, and a three-tiered patient litter. In addition, two standing ATDs were used to evaluate the benefit of Mobile Aircrew Restraint Systems (MARS) versus a standard gunner's belt. The ATD with the MARS survived the impact, while fatal head blunt trauma occurred for the standing ATD held by the legacy gunner's belt. In addition to occupant loading, the structural response of the airframe was assessed based on accelerometers located throughout the airframe and using three-dimensional photogrammetric techniques. Analysis of the photogrammetric data indicated regions of maximum deflection and permanent deformation.

Annett, Martin S.↗
NASA NTRS2023

Automated Fluidics Device for Extraction and Quantification of miRNA Biomarkers From Blood

Radiation Assessment DuRing Exposure And long-Duration Spaceflight (RADREADS) demonstrates space-compatible point-of-care technology for quantitative biological monitoring of blood miRNA biomarkers in response to long-term low dose radiation exposure. This individualized monitoring approach will inform targeted treatment strategies to maximize medical resource utilization by accounting for individual susceptibility to radiation-related illnesses. As human spaceflight progresses beyond Earth’s magnetic shielding, radiation exposure poses a significant risk to astronaut health and safety. Extended operation in this environment comes with an increased risk of radiation exposure, leading to higher risks of radiation sickness, cancer, central nervous system effects, and degenerative diseases. While conventional physical dosimetry techniques capture radiation dose, individualistic susceptibility to radiation damage is varied. Multiple characteristics, including age, body weight, sex, genetics, and immune status, have been found to influence radiosensitivity (Liu et al. 2011, and Bouffler 2016). This differential response necessitates individualized monitoring and targeted treatment strategies to maximize medical resource utilization; however, a practical diagnostic platform for quantifying long-term, low dose radiation-induced tissue damage does not currently exist. MicroRNAs (miRNAs) are a class of small, non-coding RNAs that regulate gene expression by mediating the degradation of messenger RNA. The levels of particular miRNAs are influenced by biological processes such as inflammation and serve as biomarkers for a variety of conditions including cancer (Singh et al. 2017). MicroRNAs are found in various bodily fluids and are amenable to collection via liquid biopsies, providing a minimally invasive and easily quantifiable readout for a variety of radiosensitive reporters. A preliminary signature of 15 spaceflight sensitive miRNA has been identified in rodent and human studies, including miR-21-5p, miR-24-3p, miR-92a-3p, miR-17-5p, miR-16a-3p, miR-34a-3p, and miR-223-3p. These targets generally increased expression with radiation dose and linear energy transfer, though variation between individuals is not yet described. Current gaps in the field include a lack of understanding of longitudinal biological responses to long-term, low dose radiation exposure and the absence of space-compatible point-of-care technology for quantitative biological monitoring. In this body of work, we aim to develop an automated bleed-to-read system to process whole blood for the detection of miRNA biomarkers in order to monitor individualistic responses to radiation exposure. This will be achieved via separating serum (or plasma) from whole blood, followed by extraction, amplification, and quantification of the miRNA using a RT-qPCR reaction. Previously, the WetLab-2 hardware enabled execution of a RT-qPCR reaction aboard ISS; however, it is a manual system that requires crew manipulation and bulky components (Parra et al. 2017). To address these issues, automated fluid handling hardware was developed for each stage of sample preparation. Extraction of total RNA is achieved by sequentially pumping reagents through an off-the-shelf nucleic acid binding column (miRNeasy Serum/Plasma Advanced Kit, Qiagen). This approach eliminates several manual pipetting and centrifuging steps and limits the use of toxic chemicals commonly found in other sample processing techniques. The resulting elution will then be automatically dispensed for RT-qPCR analysis using a compact rotary qPCR (Mic qPCR Cycler, Bio Molecular Systems) that will improve spaceflight compatibility by removing bubbles from the detection region, another challenge highlighted by WetLab-2 (Parra et al. 2017). Efforts are also being made to simplify the RT-qPCR reaction to a 1-step air-dryable mix to improve long-term reagent stability at room temperature and reduce system complexity. By automating the RT-qPCR processes via microfluidic manipulation, RADREADS will reduce crewmember hands-on time and enable the personalized detection of radiation-induced tissue damage during long duration missions. Minimally invasive, longitudinal monitoring of individual’s response to radiation exposure will inform how the physiological system responds to long-term low dose space radiation and enables development of targeted countermeasures by the medical team. Ultimately, this portable technology will require minimal technical expertise and can also be used to monitor miRNA biomarkers associated with other diseases.

Tristen Head↗
NASA NTRS2016

Roller Testing to Mimic Damage of the ISS SARJ Ring and Durability Test to Simulate Fifteen Years of SARJ Operation Using the Damaged Surface

The International Space Station's starboard Solar Alpha Rotary Joint (SARJ) experienced a breakdown of the joint's race ring surface. The starboard SARJ mechanism was cleaned and lubricated with grease. To provide some guidance on the expected behavior of the damaged SARJ ring with continued operations, experiments were conducted using rollers and a vacuum roller test rig. The approach of the experimental work involved three main steps: (1) initiate damage using conditions representative of the SARJ with inadequate lubrication; (2) propagate the damage by operating the test rollers without lubrication; and (3) assess the durability of the roller by testing to simulate the equivalent of 15 years of SARJ operation on the damaged surface assuming adequate grease lubrication. During the rig testing, additional and/or replacement grease was introduced at regular intervals to maintain good lubrication in the rig. The damage to the nitride layer continued even after application of grease. The grease lubrication proved to be effective for limiting the value of the axial force that can be developed. Limiting the axial force on the SARJ mechanism is important since the larger the axial force the more concentrated the load pressure becomes on the blend-radius location on the SARJ roller. After the testing simulating 15 years of SARJ operations, the wear depths were the order of 0.2 mm for the nitrided 15-5 roller and the order of 0.06 mm for the mating 440C roller. Metallographic inspections were done to search for indications of impending fatigue or other fracture indications that might eventually propagate and cause structural failure. There were no indications or features found that could eventually compromise structural integrity.

mechanical devices↗