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NASA NTRSDate not supplied

Pre-Launch Performance Trending of Joint Polar Satellite System (JPSS) Advanced Technology Microwave Sounder (ATMS)

The Advanced Technology Microwave Sounder (ATMS) microwave radiometer instrument is utilized on-board NOAA’s Joint Polar Satellite System (JPSS) fleet of spacecraft to perform temperature and water vapor soundings of Earth’s atmosphere. Consisting of 22 channels over a frequency range from 22 to 183 GHz, ATMS provides high-impact observations for numerical weather prediction (NWP) models. A general description of the ATMS instrument is discussed in [1]. There are five ATMS flight units in the polar-orbiting JPSS program; three are currently on-orbit and two are pending launch. The first ATMS was flown on the Suomi National Polar-orbiting Partnership (SNPP) satellite, launched in 2011. The second ATMS was launched on the NOAA-20 (previously JPSS-1) satellite in 2017. The third ATMS was launched on the NOAA-21 (previously JPSS-2) satellite in 2022. The SNPP and NOAA-20 ATMS units are operational. The NOAA-21 ATMS unit is completing on-orbit commissioning and checkout, having achieved provisional maturity status in December 2022 with validated maturity expected in May 2023 [2]. The fourth and fifth ATMS units are planned for the JPSS-3 (launch ~2028) and JPSS-4 (launch ~2032) satellites [3]. This paper will focus on trending performance characteristics of each JPSS ATMS build from the pre-launch activities. Pre-launch trending of some parameters have been previously published up to the JPSS-3 mission [4][5]. This paper differs from and expands the scope of the prior work as it will include all five of the JPSS ATMS builds. The entire suite of JPSS ATMS units have completed their pre-ship instrument-level I&T and verification activities. These activities include a radiometric performance characterization of each instrument. In addition to comparing the performance across builds, the performance will also be compared to requirements and specifications where applicable. The on-orbit performance of the launched units will be excluded from the scope of this paper in order to focus on evaluations that are common across all builds. The post-launch performance of SNPP ATMS is detailed in [1][6][7][8]. The post-launch performance of NOAA-20 ATMS is detailed in [6][8][9]. The pre-launch characterization of the ATMS occurs at both subassembly-level and instrument-level testing. The antenna subsystem is tested at Northrop Grumman’s Compact Antenna Test Range (CATR) in Azusa, CA [9]. This testing characterizes the antenna pattern and the pointing performance of the scan drive mechanism and antenna subsystem. Trended parameters from this evaluation will include beam pointing accuracy, beamwidth, and beam efficiency. These parameters are captured in each instrument’s Calibration Data Book [10]. Instrument-level radiometric performance evaluation is primarily done during thermal vacuum (TVAC) calibration testing at Northrop Grumman’s Azusa, CA facility [9]. A general description of the calibration activities is presented in [1][9]. The testing involves inferring a scene target brightness temperature (TB) and comparing it to the actual scene TB while the instrument is at flight-like temperature and pressure environmental conditions. Trended parameters from this activity will include Noise Equivalent Delta Temperature (NEDT), nonlinearity, radiometric accuracy, gain stability, striping, and inter-channel noise correlation. The trending evaluation will allow for a direct comparison of the ATMS performance across builds. The paper will highlight observed performance improvements.

Edward J Kim↗

NASA NTRS2018

Advanced Environmental Barrier Coating and SA Tyrannohex SiC Composites Integration for Improved Thermomechanical and Environmental Durability

The development of 2700 degF capable environmental barrier coating (EBC) systems, particularly, the Rare Earth "Hafnium" Silicon bond coat systems, have significantly improved the temperature capability and environmental stability of SiC/SiC Ceramic Matrix Composite Systems. We have specifically developed the advanced 2700 degF EBC systems, integrating the EBC to the high temperature SA Tyrannohex SiC fiber composites, for comprehensive performance and durability evaluations for potential turbine engine airfoil component applications. The fundamental mechanical properties, environmental stability and thermal gradient cyclic durability performance of the EBC - SA Tyrannohex composites were investigated. The paper will particularly emphasize the high pressure combustion rig recession, cyclic thermal stress resistance and thermomechanical low cycle fatigue testing of uncoated and environmental barrier coated Tyrannohex SiC SA composites in these simulated turbine engine combustion water vapor, thermal gradients, and mechanical loading conditions. We have also investigated high heat flux and flexural fatigue degradation mechanisms, determined the upper limits of operating temperature conditions for the coated SA composite material systems in thermomechanical fatigue conditions. Recent progress has also been made by using the self-healing rare earth-silicon based EBCs, thus enhancing the SA composite hexagonal fiber columns bonding for improved thermomechanical and environmental durability in turbine engine operation environments. More advanced EBC- composite systems based on the new EBC-Fiber Interphases will also be discussed.

Tyrannohex SiC Ceramics↗

NASA NTRS1985

Portable Temperature Set-Point Controller

Two off-the-shelf instruments combine to control chamber temperature over wide range. Portable controller for environmental test chambers changes temperatures automatically over range of -300 degrees to +400 degrees F (-184 degrees to + 204 degrees C). Unit controls rate of temperature change and time at given temperature. Controller developed to meet NASA Shuttle test requirements.

Milner, J. F.↗

NASA NTRS1994

The Influence of Sound Cues on the Maintenance of Temporal Organization in the Sprague-Dawley Rat

Temporal organization is a fundamental property of living matter. From single cells to complex animals including man, most physiological systems undergo daily periodic changes in concert with environmental cues (e.g., light, temperature etc.). It is known that pulsed Environmental synchronizers, zeitgebers, (e.g. light) can modify rhythm parameters. Rhythm stability is a necessary requirement for most animal experiments. The extent to which sound can influence the circadian system of laboratory rats is poorly understood. This has implications to animal habitats in the novel environments of the Space-Laboratory or Space Station. A series of three white noise (88+/-0.82 db) zeitgeber experiments were conducted (n=6/experiment).The sound cue was introduced in the circadian free-running phase (DD-NQ) and in one additional case sound was added to the usual photoperiod (12L:12D) to determine masking effects. Circadian rhythm parameters of drinking frequency, feeding frequency, and gross locomotor activity were continuously monitored. Data analysis for these studies included macroscopic and microscopic methods. Raster plots to visually detect entrainment versus free-running period, were plotted for each animal, for all three parameters, during all sound perturbation tested. These data were processed through a series of detrending (robust locally weighted regression analyses) and complex demodulation analyses. In summary, these findings show that periodic "white" noise "influences" the rats circadian system but does not "entrain" the feeding, drinking or locomotor activity rhythms.

Winget, C. M.↗

NASA NTRS1990

Optical fibers in the adverse space environment - The Space Station

On the NASA Space Station, the requirement for high speed data transfer between the exterior experimental bays and the interior research facilities has generated the need for fiberoptics. The adverse vacuum effects in space, temperature extremes, and natural space radiation place extreme conditions on optical fiber interconnects. This report addresses the adverse space environmental effects of temperature and radiation on optical fibers.

Greenwell, Roger A.↗

NASA NTRS1997

SiC Recession Due to SiO2 Scale Volatility Under Combustor Conditions

One of today's most important and challenging technological problems is the development of advanced materials and processes required to design and build a fleet of supersonic High Speed Civil Transport (HSCT) airliners, a follow-up to the Concorde SST. The innovative combustor designs required for HSCT engines will need high-temperature materials with long-term environmental stability. Higher combustor liner temperatures than today's engines and the need for lightweight materials will require the use of advanced ceramic-matrix composites (CMC's) in hot-section components. The HSCT is just one example being used to demonstrate the need for such materials. This thesis evaluates silicon carbide (SiC) as a potential base material for HSCT and other similar applications. Key issues are the environmental durability for the materials of interest. One of the leading combustor design schemes leads to an environment which will contain both oxidizing and reducing gas mixtures. The concern is that these environments may affect the stability of the silica (SiO2) scale on which SiC depends for environmental protection. A unique High Pressure Burner Rig (HPBR) was developed to simulate the combustor conditions of future gas turbine engines, and a series of tests were conducted on commercially available SiC material. These tests are intended as a feasibility study for the use of these materials in applications such as the HSCT. Linear weight loss and surface recession of the SiC is observed as a result of SiO2 volatility for both fuel-lean and fuel-rich gas mixtures. These observations are compared and agree well with thermogravimetric analysis (TGA) experiments. A strong Arrhenius-type temperature dependence exists. In addition, the secondary dependencies of pressure and gas velocity are defined. As a result, a model is developed to enable extrapolation to points outside the experimental space of the burner rig, and in particular, to potential gas turbine engine conditions.

Robinson, Raymond Craig↗

NASA NTRSDate not supplied

TPSAS-NF1676L-31185-DND

Accurate predictive modeling of EPA-defined criteria pollutants in transition zones such as the land/water interface has proven challenging due to differing emission sources, meteorology, and environmental conditions (e.g. temperature, humidity). Chemical species that are “trapped" over water may contribute to exceedence events over land due to land/sea breeze events. The Ozone Water-Land Environmental Transition Study (OWLETS) during the 2017 summer was initiated to study how ozone and ozone precursor concentrations differ over two proximate sites (separated by 20 km). One site (NASA's Langley Research Center) is a land-based site, with the second site being located on the third island of the Chesapeake Bay Bridge Tunnel, approximately 14 km offshore. Both sites had ozone lidars from the Tropospheric Ozone Lidar NETwork(TOLNET) for continuous profiling of the boundary layer and lower-tropospheric ozone and sounding capabilities for profiling the atmosphere up to 35 km. Coincident sonde launches were conducted from both sites to allow intercomparison of ozone mixing ratios and temperature/humidity. Preliminary results regarding ozone gradients are presented herein.

E Gargulinski↗

NASA NTRS2006

Advances in Hot-Structure Development

The National Aeronautics and Space Administration has actively participated in the development of hot structures technology for application to hypersonic flight systems. Hot structures have been developed for vehicles including the X-43A, X-37, and the Space Shuttle. These trans-atmospheric and atmospheric entry flight systems that incorporate hot-structures technology are lighter weight and require less maintenance than those that incorporate parasitic, thermal-protection materials that attach to warm or cool substructure. The development of hot structures requires a thorough understanding of material performance in an extreme environment, boundary conditions and load interactions, structural joint performance, and thermal and mechanical performance of integrated structural systems that operate at temperatures ranging from 1500 C to 3000 C, depending on the application. This paper will present recent advances in the development of hot structures, including development of environmentally durable, high temperature leading edges and control surfaces, integrated thermal protection systems, and repair technologies. The X-43A Mach-10 vehicle utilized carbon/carbon (C/C) leading edges on the nose, horizontal control surface, and vertical tail. The nose and vertical and horizontal tail leading edges were fabricated out of a 3:1 biased, high thermal conductivity C/C. The leading edges were coated with a three-layer coating comprised of a SiC conversion of the C/C, followed by a CVD layer of SiC, followed by a thin CVD layer of HfC. Work has also been performed on the development of an integrated structure and was focused on both hot and warm (insulated) structures and integrated fuselage/tank/TPS systems. The objective was to develop integrated multifunctional airframe structures that eliminate fragile external thermal-protection systems and incorporate the insulating function within the structure. The approach taken to achieve this goal was to develop candidate hypersonic airframe concepts, including structural arrangement, load paths, thermal-structural wall design, thermal accommodation features, and integration of major components, optimize thermalstructural configurations, and validate concepts through a building block test program and generate data to improve and validate analytical and design tools.

Rivers, H. Kevin↗

NASA NTRS1987

High temperature metal matrix composites for future aerospace systems

Research was conducted on metal matrix composites and intermetallic matrix composites to understand their behavior under anticipated future operating conditions envisioned for aerospace power and propulsion systems of the 21st century. Extremes in environmental conditions, high temperature, long operating lives, and cyclic conditions dictate that the test evaluations not only include laboratory testing, but simulated flight conditions. The various processing techniques employed to fabricate composites are discussed along with the basic research underway to understand the behavior of high temperature composites, and the relationship of this research to future aerospace systems.

Stephens, Joseph R.↗

NASA NTRS1988

High temperature metal matrix composites for future aerospace systems

Stephens, Joseph R.↗

NASA NTRS1979

Graphite fiber reinforced glass matrix composites for aerospace applications

The graphite fiber reinforced glass matrix composite system is described. Although this composite is not yet a mature material, it possesses low density, attractive mechanical properties at elevated temperatures, and good environmental stability. Properties are reported for a borosilicate glass matrix unidirectionally reinforced with 60 volume percent HMS graphite fiber. The flexural strength and fatigue characteristics at room and elevated temperature, resistance to thermal cycling and continuous high temperature oxidation, and thermal expansion characteristics of the composite are reported. The properties of this new composite are compared to those of advanced resin and metal matrix composites showing that graphite fiber reinforced glass matrix composites are attractive for aerospace applications.

Prewo, K. M.↗

NASA NTRS2011

International Space Station Environmental Control and Life Support System Acceptance Testing for Node 1 Temperature and Humidity Control Subsystem

The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Storage (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper will provide a summary of the Node 1 ECLS THC subsystem design and a detailed discussion of the ISS ECLS Acceptance Testing methodology utilized for this subsystem.The International Space Station (ISS) Node 1 Environmental Control and Life Support (ECLS) System is comprised of five subsystems: Atmosphere Control and Storage (ACS), Atmosphere Revitalization (AR), Fire Detection and Suppression (FDS), Temperature and Humidity Control (THC), and Water Recovery and Management (WRM). This paper will provide a summary of the Node 1 ECLS THC subsystem design and a detailed discussion of the ISS ECLS Acceptance Testing methodology utilized for this subsystem.

Williams, David E.↗

NASA NTRS1974

Determination of failure limits for sterilizable solid rocket motor

A structural evaluation to establish probable failure limits and a series of environmental tests involving temperature cycling, sustained acceleration, and vibration were conducted on an 18-inch diameter solid rocket motor. Despite the fact that thermal, acceleration and vibration loads representing a severe overtest of conventional environmental requirements were imposed on the sterilizable motor, no structural failure of the grain or flexible support system was detected. The following significant conclusions are considered justified. It is concluded that: (1) the flexible grain retention system, which permitted heat sterilization at 275 F on the test motor, can readily be adopted to meet the environmental requirements of an operational motor design, and (2) if further substantiation of structural integrity is desired, the motor used is considered acceptable for static firing.

Lambert, W. L.↗

NASA NTRS1975

Graphite fiber reinforced thermoplastic resins

Mechanical properties of neat resin samples and graphite fiber reinforced samples of thermoplastic resins were characterized with particular emphasis directed to the effects of environmental exposure (humidity, temperature and ultraviolet radiation). Tensile, flexural, interlaminar shear, creep and impact strengths were measured for polysulfone, polyarylsulfone and a state-of-the-art epoxy resin samples. In general, the thermoplastic resins exhibited environmental degradation resistance equal to or superior to the reference epoxy resin. Demonstration of the utility and quality of a graphite/thermoplastic resin system was accomplished by successfully thermoforming a simulated compressor blade and a fan exit guide vane.

Novak, R. C.↗

NASA NTRS2023

Chapter Fourteen - Space Photovoltaics for Extreme High-Temperature Missions

Solar arrays in space are subjected to a daunting set of environmental hazards, including extreme temperature cycles, particulate and ultraviolet radiation in space, micrometeoroid damage, and exposure to a flux of atomic oxygen in low-Earth orbit. Over the years since the first solar cells were sent into space on Vanguard 1 in 1958, space solar array technology has advanced to develop photovoltaic materials, cells, and arrays resistant to these degradation mechanisms. This chapter highlights approaches to solar array design for near-Sun missions including thermal management at the systems level, to optimize efficiency at elevated temperature, or the use of novel device design to reduce the incident solar energy to limit operating temperature. Several of these have been successfully demonstrated to enable solar-powered spacecraft to explore the near-Sun planets such as Mercury and Venus as well as the Sun itself.

Space photooltaics↗

NASA NTRS2007

Advanced Woven SiC/SiC Composites for High Temperature Applications

The temperature, stress, and environmental conditions of many gas turbine, hypersonic, and even nuclear applications make the use of woven SiC/SiC composites an attractive enabling material system. The development in SiC/SiC composites over the past few years has resulted in significant advances in high temperature performance so that now these materials are being pursued for several turbine airfoil and reusable hypersonic applications. The keys to maximizing stress capability and maximizing temperature capability will be outlined for SiC/SiC. These include the type of SiC fiber, the fiber-architecture, and the matrix processing approach which leads to a variety of matrix compositions and structure. It will also be shown that a range of mechanical, thermal, and permeability properties can be attained and tailored depending on the needs of an application. Finally, some of the remaining challenges will be discussed in order for the use of these composite systems to be fully realized.

Morscher, Gregory N.↗

NASA NTRS1971

Operating frequencies for educational satellite services

The factors affecting the choice of transmission frequencies are identified. These include international radio regulations, natural environment, man-made environment, hardware considerations, and interconnection and spectrum space considerations. An analysis is presented of international radio regulations with emphasis on 1963 EARC and 1971 WARC frequency allocations, powerflux density restrictions, and resolutions concerning introduction of broadcasting-satellite systems. Natural-environmental effects were divided into two categories: (1) those due to transionospheric propagation, and (2) those that can be credited to the earth's atmosphere and its constituents. The frequency dependence of the signal attenuation, signal distortion, and contributions to system noise temperature due to environmental effects are discussed, and comparisons were made for frequencies of interest. Man-made environmental effects were examined in terms of various sharing limitations as well as the indigenous noise contribution to the overall system noise.

Singh, J. P.↗

NASA NTRS1974

Environmental protection of titanium alloys at high temperatures

Various concepts were evaluated for protecting titanium alloys from oxygen contamination at 922 K (1200 F) and from hot-salt stress-corrosion at 755 K (900 F). It is indicated that oxygen-contamination resistance can be provided by a number of systems, but for hot-salt stress-corrosion resistance, factors such as coating integrity become very important. Titanium aluminides resist oxygen ingress at 922 K through the formation of alumina (on TiAl3) or modified TiO2 (on Ti3Al, TiAl) scales. TiAl has some resistance to attack by hot salt, but has limited ductility. Ductile Ti-Ni and Ti-Nb-Cr-Al alloys provide limited resistance to oxygen ingress, but are not greatly susceptible to hot-salt stress-corrosion cracking.

Wright, I. G.↗