Results for “Harsh Environments” — Page 28

NASA NTRSDate not supplied

Waste Container Filtration to Minimize Microbial Escape During Long-Term Storage on Mars

In the search for life on Mars, keeping its surface pristine and free of microbes due to human presence is of utmost importance. Astronauts will use emptied logistics containers during their Mars stay to store waste. These containers will be left on the planet’s surface and are a potential source of microorganism contamination. It is desired for these containers to be free from leaks for a minimum of 50 years. If leaks do occur, a likely location will be at any ports. At these locations the mating surfaces will be sealed using a flexible gasket material like a thin metal or a polymer. Eventually these seals will fail. To mitigate these effects, a particulate filter can be employed to equilibrate the pressure between the Martin environment and inside the container. To meet planetary protection requirements, the filter can only allow particulates smaller than 0.2 m diameter to pass. This paper discusses why a particulate filter may be needed and how such a filter could be tested to survive and operate in the harsh Martian environment.

planetary protection↗

NASA NTRSDate not supplied

Waste Container Filtration to Minimize Microbial Escape During Long-Term Storage on Mars

In the search for life on Mars, keeping its surface pristine and free of microbes due to human presence is of utmost importance. Astronauts will use emptied logistics containers during their Mars stay to store waste. These containers will be left on the planet’s surface and are a potential source of microorganism contamination. It is desired for these containers to be free from leaks for a minimum of 50 years. If leaks do occur, a likely location will be at any ports. At these locations the mating surfaces will be sealed using a flexible gasket material like a thin metal or a polymer. Eventually these seals will fail. To mitigate these effects, a particulate filter can be employed to equilibrate the pressure between the Martin environment and inside the container. To meet planetary protection requirements, the filter can only allow particulates smaller than 0.2 μm diameter to pass. This paper discusses why a particulate filter may be needed and how such a filter could be tested to survive and operate in the harsh Martian environment.

planetary protection↗

NASA NTRS2010

Installation and Characterization of Charged Particle Sources for Space Environmental Effects Testing

Charged particle sources are integral devices used by Marshall Space Flight Center s Environmental Effects Branch (EM50) in order to simulate space environments for accurate testing of materials and systems. By using these sources inside custom vacuum systems, materials can be tested to determine charging and discharging properties as well as resistance to sputter damage. This knowledge can enable scientists and engineers to choose proper materials that will not fail in harsh space environments. This paper combines the steps utilized to build a low energy electron gun (The "Skevington 3000") as well as the methods used to characterize the output of both the Skevington 3000 and a manufactured Xenon ion source. Such characterizations include beam flux, beam uniformity, and beam energy. Both sources were deemed suitable for simulating environments in future testing.

Skevington, Jennifer L.↗

NASA NTRS2008

Lunar Communication Terminals for NASA Exploration Missions: Needs, Operations Concepts and Architectures

NASA is conducting architecture studies prior to deploying a series of short- and long-duration human and robotic missions for the exploration of the Moon and Mars under the Vision for Space Exploration Initiative. A key objective of these missions is to establish and expand, through a series of launches, a system of systems approach to exploration capabilities and science return. The systems identified were Crew Exploration Vehicles, crew and cargo launch vehicles, crew EVA suits, crew and cargo landers, habitats, mobility carriers, and small, pressurized rovers. Multiple space communication networks and systems, deployed over time, will support these space exploration systems of systems. Each deployment phase will support interoperability of components and provide 20 years of legacy systems. In this paper, we describe the modular lunar communications terminals needed for the emerging lunar mission operational scenarios. These lunar communication terminals require flexibility for use in stationary, integrated, and mobile environments. They will support links directly to Earth, to lunar relay satellites, to astronauts and to fixed and mobile lunar surface systems. The operating concepts and traffic models are presented for these terminals within variety of lunar scenarios. A preliminary architecture is outlined, providing for suitable long-duration operations in the harsh lunar environment.

Bhasin, Kul B.↗

NASA NTRSDate not supplied

Testbed for Lunar Extreme Environment Wear Tolerant Applications

The abrasive dust from lunar regolith poses significant long-term durability and performance challenges to materials, vehicles, mechanisms and structures that will be used for the next generation of lunar exploration. The development of advanced materials, coatings and device technologies that can withstand these abrasive particles and extreme environmental conditions is critical. However, the lack of standardized and accessible methods for evaluating such materials and devices in a facsimile of the harsh lunar environment hinders progress in dust-tolerant technologies. To address this challenge, NASA Langley Research Center is creating an extreme environment testbed. This reconfigurable testbed will allow rapid, repeatable wear testing of material and candidate mechanisms under vacuum conditions, facilitating the development of critical materials technologies for lunar exploration. Preliminary results from exposing an actuating mechanism similar to a pin joint to lunar regolith simulant under high vacuum are reported.

lunar dust↗

NASA NTRSDate not supplied

Testbed for Lunar Extreme Environment Wear Tolerant Applications

The abrasive dust from lunar regolith poses significant long-term durability and performance challenges to materials, vehicles, mechanisms and structures that will be used for the next generation of lunar exploration. The development of advanced materials, coatings and device technologies that can withstand these abrasive particles and extreme environmental conditions is critical. However, the lack of standardized and accessible methods for evaluating such materials and devices in a facsimile of the harsh lunar environment hinders progress in dust-tolerant technologies. To address this challenge, NASA Langley Research Center is creating an extreme environment testbed. This reconfigurable testbed will allow rapid, repeatable wear testing of material and candidate mechanisms under vacuum conditions, facilitating the development of critical materials technologies for lunar exploration. Preliminary results from exposing an actuating mechanism similar to a pin joint to lunar regolith simulant under high vacuum are reported.

lunar dust↗

NASA NTRSDate not supplied

Testbed for Lunar Extreme Environment Wear Tolerant Applications

The abrasive dust from lunar regolith poses significant long-term durability and performance challenges to materials, vehicles, mechanisms and structures that will be used for the next generation of lunar exploration. The development of advanced materials, coatings and device technologies that can withstand these abrasive particles and extreme environmental conditions is critical. However, the lack of standardized and accessible methods for evaluating such materials and devices in a facsimile of the harsh lunar environment hinders progress in dust-tolerant technologies. To address this challenge, NASA Langley Research Center is creating an extreme environment testbed. This reconfigurable testbed will allow rapid, repeatable wear testing of material and candidate mechanisms under vacuum conditions, facilitating the development of critical materials technologies for lunar exploration. Preliminary results from exposing an actuating mechanism similar to a pin joint to lunar regolith simulant under high vacuum are reported.

lunar dust↗

NASA NTRS2021

Advancing Space Life Science Research Using Drosophila Melanogaster

As we embark on exploring deep space, it is imperative to unravel the impacts of such unique and dynamic environments on biological systems. Multiple studies using D. melanogaster, a well-established spaceflight model, have paved the way towards our understanding of spaceflight-associated health risks. Further, Drosophila quantitative genomic experiments along with improved automated hardware systems will enable efficient and effective identification of the underlying genetic and molecular determinants capable of physiological adaptation to endure harsh space environments.

Quantitative genomics↗

NASA NTRS2007

Gyro Evaluation for the Mission to Jupiter

As an important component in NASA's New Frontiers Program, the Jupiter Polar Orbiter (Juno) mission is designed to investigate in-depth physical properties of Jupiter. It will include the giant planet's ice-rock core and atmospheric studies as well as exploration of its polar magnetosphere. It will also provide the opportunity to understand the origin of the Jovian magnetic field. Due to severe radiation environment of the Jovian system, this mission inherently presents a significant technical challenge to Attitude Control System (ACS) design since the ACS sensors must survive and function properly to reliably maneuver the spacecraft throughout the mission. Different gyro technologies and their critical performance characteristics are discussed, compared and evaluated to facilitate a choice of appropriate gyro-based inertial measurement unit to operate in a harsh Jovian environment to assure mission success.

physical properties↗

NASA NTRS1978

Sealing scientific probes against deep space and the Venusian environment A tough job

The Pioneer Venus mission evolved from studies conducted during the late 1960s and early 1970s. It was found that a need existed for low cost orbiters and landers to explore the planet. The considered mission was to be accomplished with six separate vehicles arriving at Venus nearly simultaneously in mid-December 1978. The probes are designed to survive entry and descent into the atmosphere. A description is presented of the approaches used to maintain sealing integrity for the large and small probes under the constraints imposed by the harsh Venusian environment. Attention is given to probe vehicle configuration, pressure vessel sealing requirements, material and configuration considerations, permanent seals, separable seals, development problems, and aspects of seal testing.

Pokras, J.↗

NASA NTRS2016

TransFormers for Ensuring Long-Term Operations in Lunar Extreme Environments

"Surviving Extreme Space Environments" (EE) is one of NASA's Space Technology Grand Challenges. Power generation and thermal control are the key survival ingredients that allow a robotic explorer to cope with the EE using resources available to it, for example, by harvesting the local solar energy or by utilizing an onboard radioisotope thermoelectric generator (RTG). TransFormers (TFs) are a new technology concept designed to transform a localized area within a harsh extreme environment into a survivable micro-environment by projecting energy to the precise location where robots or humans operate. For example, TFs placed at a location on the rim of Shackleton Crater, which is illuminated by solar radiation for most of the year, would be able to reflect solar energy onto robots operating in the dark cold crater. TFs utilize a shape transformation mechanism to un-fold from a compact volume to a large reflective surface, and to control how much-and where-the energy is projected, and by adjusting for the changing position of the sun. TFs would enable in-situ resource utilization (ISRU) activities within locations of high interest that would normally be unreachable because of their extreme environment

ISRU↗

NASA NTRS2011

The Effect of Dose Rate on Composite Durability When Exposed to a Simulated Long-Term Lunar Radiation Environment

Human exploration of space beyond low Earth orbit (LEO) requires a safe living and working environment for crew. Composite materials are one type of material being investigated by NASA as a multi-functional structural approach to habitats for long-term use in space or on planetary surfaces with limited magnetic fields and atmosphere. These materials provide high strength with the potential for decreased weight and increased radiation protection of crew and electronics when compared with conventional aluminum structures. However, these materials have not been evaluated in a harsh radiation environment, as would be experienced outside of LEO or on a planetary surface. Thus, NASA has been investigating the durability of select composite materials in a long-term radiation environment. Previously, NASA exposed composite samples to a simulated, accelerated 30-year radiation treatment and tensile stresses similar to those of a habitat pressure vessel. The results showed evidence of potential surface oxidation and enhanced cross-linking of the matrix. As a follow-on study, we performed the same accelerated exposure alongside an exposure with a decreased dose rate. The slower dose ]rate is comparable to a realistic scenario, although still accelerated. Strain measurements were collected during exposure and showed that with a fastdose rate, the strain decreased with time, but with a slow ]dose rate, the strain increased with time. After the radiation exposures, samples were characterized via tensile tests, flexure tests, Fourier Transform Infrared Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC). The results of these tests will be discussed.

Rojdev, Kristina↗

NASA NTRS2011

Plug-and-Play Environmental Monitoring Spacecraft Subsystem

A Space Environment Monitor (SEM) subsystem architecture has been developed and demonstrated that can benefit future spacecraft by providing (1) real-time knowledge of the spacecraft state in terms of exposure to the environment; (2) critical, instantaneous information for anomaly resolution; and (3) invaluable environmental data for designing future missions. The SEM architecture consists of a network of plug-and- play (PnP) Sensor Interface Units (SIUs), each servicing one or more environmental sensors. The SEM architecture is influenced by the IEEE Smart Transducer Interface Bus standard (IEEE Std 1451) for its PnP functionality. A network of PnP Spacecraft SIUs is enabling technology for gathering continuous real-time information critical to validating spacecraft health in harsh space environments. The demonstrated system that provided a proof-of-concept of the SEM architecture consisted of three SIUs for measurement of total ionizing dose (TID) and single event upset (SEU) radiation effects, electromagnetic interference (EMI), and deep dielectric charging through use of a prototype Internal Electro-Static Discharge Monitor (IESDM). Each SIU consists of two stacked 2X2 in. (approximately 5X5 cm) circuit boards: a Bus Interface Unit (BIU) board that provides data conversion, processing and connection to the SEM power-and-data bus, and a Sensor Interface Electronics (SIE) board that provides sensor interface needs and data path connection to the BIU.

Patel, Jagdish↗

NASA NTRS2015

On Possible Arc Inception on Low Voltage Solar Array

Recent analysis of spacecraft failures during the period of 1990-2013 demonstrated clearly that electrostatic discharges caused more than 8 of all registered failures and anomalies, and comprised the most costly losses (25) for operating companies and agencies. The electrostatic discharges on spacecraft surfaces are the results of differential charging above some critical (threshold) voltages. The mechanisms of differential charging are well known, and various methods have been developed to prevent a generation of significant electric fields in areas of triple junctions. For example, low bus voltages in Low Earth Orbit plasma environment and slightly conducting layer over coverglass (ITO) in Geosynchronous Orbit surroundings are believed to be quite reliable measures to prevent discharges on respective surfaces. In most cases, the vulnerable elements of spacecraft (solar arrays, diode boards, etc.) go through comprehensive ground tests in vacuum chambers. However, tests articles contain the miniscule fragments of spacecraft components such as 10-30 solar cells of many thousands deployed on spacecraft in orbit. This is one reason why manufacturing defects may not be revealed in ground tests but expose themselves in arcing on array surface in space. The other reason for ineffectiveness of discharge preventive measures is aging of all materials in harsh orbital environments. The expected life time of modern spacecraft varies within the range of five-fifteen years, and thermal cycling, radiation damages, and mechanical stresses can result in surface erosion on conductive layers and microscopic cracks in coverglass sheets and adhesive films. These possible damages may cause significant increases in local electric field strengths and subsequent discharges. The primary discharges may or may not be detrimental to spacecraft operation, but they can produce the necessary conditions for sustained arcs initiation. Multiple measures were developed to prevent sustained discharges between adjacent strings, and many ground tests were performed to determine threshold parameters (voltage and current) for sustained arcs. And again, manufacturing defects and aging in space environments may result in considerable decrease of critical threshold parameters. This paper is devoted to the analysis of possible reasons behind arcing on spacecraft with low bus voltages.

plasma interaction↗

NASA NTRS2015

On Possible Arc Inception on Low Voltage Solar Array

Recent analysis of spacecraft failures during the period of 1990-2013 demonstrated clearly that electrostatic discharges caused more than 8 percent of all registered failures and anomalies, and comprised the most costly losses (25 percent) for operating companies and agencies. The electrostatic discharges on spacecraft surfaces are the results of differential charging above some critical (threshold) voltages. The mechanisms of differential charging are well known, and various methods have been developed to prevent a generation of significant electric fields in areas of triple junctions. For example, low bus voltages in Low Earth Orbit plasma environment and slightly conducting layer over cover-glass (ITO) in Geosynchronous Orbit surroundings are believed to be quite reliable measures to prevent discharges on respective surfaces. In most cases, the vulnerable elements of spacecraft (solar arrays, diode boards, etc.) go through comprehensive ground tests in vacuum chambers. However, tests articles contain the miniscule fragments of spacecraft components such as 10-30 solar cells of many thousands deployed on spacecraft in orbit. This is one reason why manufacturing defects may not be revealed in ground tests but expose themselves in arcing on array surface in space. The other reason for ineffectiveness of discharge preventive measures is aging of all materials in harsh orbital environments. The expected life time of modern spacecraft varies within the range of five-fifteen years, and thermal cycling, radiation damages, and mechanical stresses can result in surface erosion on conductive layers and microscopic cracks in cover-glass sheets and adhesive films. These possible damages may cause significant increases in local electric field strengths and subsequent discharges. The primary discharges may or may not be detrimental to spacecraft operation, but they can produce the necessary conditions for sustained arcs initiation. Multiple measures were developed to prevent sustained discharges between adjacent strings, and many ground tests were performed to determine threshold parameters (voltage and current) for sustained arcs. And again, manufacturing defects and aging in space environments may result in considerable decrease of critical threshold parameters. This paper is devoted to the analysis of possible reasons behind arcing on spacecraft with low bus voltages.

low voltage solar array↗

NASA NTRS2013

Integration and Ruggedization of a Commercially Available Gas Chromatograph and Mass Spectrometer (GCMS) for the Resource Prospector Mission (RPM)

The Resource Prospector is a mission to prospect for lunar volatiles (primarily water) at one of the two lunar poles, as well as demonstrate In-Situ Resource Utilization (ISRU) on the Moon. The Resource Prospector consists of a lander, a rover, and a rover-borne scientific payload. The Regolith and Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) payload, will be able to (1) locate near subsurface volatiles, (2) excavate and analyze samples of the volatile-bearing regolith, and (3) demonstrate the form, extractability and usefulness of the materials. The gas chromatograph mass spectrometer (GCMS) is the primary instrument in the RESOLVE instrumentation suite responsible for identification and quantification of the volatiles evolved from the lunar regolith. Specifically, this instrument must have: a low mass, a low power consumption, be able to perform fast analyses of samples ranging from less than one to greater than ninety nine percent water by mass, be autonomously controlled by the payload's software and avionics platform, and be able to operate in the harsh lunar environment. The RPM's short mission duration is the primary driver of the requirement for a very fast analysis time currently base lined at less than 2 minutes per sample. This presentation will discuss the requirements levied upon the GCMS design, lessons learned from a preliminary field demonstration deployment, the current design, and the path forward.

Loftin, Kathleen↗

NASA NTRS2013

Integration and Ruggedization of a Commercially Available Gas Chromatograph and Mass Spectrometer (GCMS) for the Resource Prospector Mission (RPM)

The Resource Prospector is a mission to prospect for lunar volatiles (primarily water) at one of the two lunar poles, as well as demonstrate In-Situ Resource Utilization (ISRU) on the Moon. The Resource Prospector consists of a lander, a rover, and a rover-borne scientific payload. The Regolith and Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) payload, will be able to (1) locate near subsurface volatiles, (2) excavate and analyze samples of the volatile-bearing regolith, and (3) demonstrate the form, extractability and usefulness of the materials. The gas chromatograph mass spectrometer (GCMS) is the primary instrument in the RESOLVE instrumentation suite responsible for identification and quantification of the volatiles evolved from the lunar regolith. Specifically, this instrument must have: a low mass, a low power consumption, be able to perform fast analyses of samples ranging from less than one to greater than ninety nine percent water by mass, be autonomously controlled by the payload's software and avionics platform, and be able to operate in the harsh lunar environment. The RPM's short mission duration is the primary driver of the requirement for a very fast analysis time currently base lined at less than 2 minutes per sample. This presentation will discuss the requirements levied upon the GCMS design, lessons learned from a preliminary field demonstration deployment, the current design, and the path forward.

Loftin, Kathleen↗

NASA NTRS2003

Structural Anomalies Detected in Ceramic Matrix Composites Using Combined Nondestructive Evaluation and Finite Element Analysis (NDE and FEA)

Most reverse engineering approaches involve imaging or digitizing an object and then creating a computerized reconstruction that can be integrated, in three dimensions, into a particular design environment. The rapid prototyping technique builds high-quality physical prototypes directly from computer-aided design files. This fundamental technique for interpreting and interacting with large data sets is being used here via Velocity2 (an integrated image-processing software, ref. 1) using computed tomography (CT) data to produce a prototype three-dimensional test specimen model for analyses. A study at the NASA Glenn Research Center proposes to use these capabilities to conduct a combined nondestructive evaluation (NDE) and finite element analysis (FEA) to screen pretest and posttest structural anomalies in structural components. A tensile specimen made of silicon nitrite (Si3N4) ceramic matrix composite was considered to evaluate structural durability and deformity. Ceramic matrix composites are being sought as candidate materials to replace nickel-base superalloys for turbine engine applications. They have the unique characteristics of being able to withstand higher operating temperatures and harsh combustion environments. In addition, their low densities relative to metals help reduce component mass (ref. 2). Detailed three-dimensional volume rendering of the tensile test specimen was successfully carried out with Velocity2 (ref. 1) using two-dimensional images that were generated via computed tomography. Subsequent, three-dimensional finite element analyses were performed, and the results obtained were compared with those predicted by NDE-based calculations and experimental tests. It was shown that Velocity2 software can be used to render a three-dimensional object from a series of CT scan images with a minimum level of complexity. The analytical results (ref. 3) show that the high-stress regions correlated well with the damage sites identified by the CT scans and the experimental data. Furthermore, modeling of the voids collected via NDE offered an analytical advantage that resulted in more accurate assessments of the material s structural strength. The top figure shows a CT scan image of the specimen test section illustrating various hidden structural entities in the material and an optical image of the test specimen considered in this study. The bottom figure represents the stress response predicted from the finite element analyses (ref .3 ) for a selected CT slice where it clearly illustrates the correspondence of the high stress risers due to voids in the material with those predicted by the NDE. This study is continuing, and efforts are concentrated on improving the modeling capabilities to imitate the structural anomalies as detected.

Abdul-Aziz, Ali↗