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NASA NTRS2011

The Diviner Lunar Radiometer Compositional Data Products: Description and Examples

The Diviner lunar radiometer has made the first direct global measurements of silicate mineralogy of the lunar surface using multispectral thermal emission mapping. By mid-March, 2011, the first derived compositional data products (level 3) will be released into the Planetary Data System (PDS) Geosciences Node. These products describe the Diviner Science Team's best efforts to determine the position of the Christiansen feature (CF), which is directly related to silicate mineralogy of lunar soils. The initial release of these products include data from the mission's primary mapping phase between 9/17/09 and 9/16/10. This work describes at a high level the creation of Diviner's compositional data products.

Diviner Lunar Radiometer↗
DOE OSTI2022

Pd and octahedra do not get along: Square planar [PdS 4 ] units in non-centrosymmetric La 6 PdSi 2 S 14

Non-linear optical (NLO) materials require a balance of high second-harmonic generation (SHG) signal and laser damage threshold (LDT), as well as phase matchable behavior. Herein, we report a new member of the (RE) 6 (TM) x (Tt) 2 Q 14 family of compounds, La 6 PdSi 2 S 14 , which, unlike all other reported TM analogues crystallizing in hexagonal P6 3 space group, crystallizes in the non-centrosymmetric monoclinic P2 1 space group. The crystal structure contains chains of edge-sharing distorted square planar [PdS 4 ] units. The square-planar coordination of Pd in La 6 PdSi 2 S 14 exhibits remarkable NLO properties with high SHG (3.7 × AgGaS 2 ) and LDT (3 × AgGaS 2 ) values as well as phase matchability. This shows the promise of novel materials with distorted structural motifs for enhanced NLO properties. Further, upon formation of bimetallic chiral sulfides containing both Cu and Pd, Cu occupies the opposite faces of the octahedra forming [CuS 3 ] units while Pd can be stabilized in the center of PdS 6 octahedra in the hexagonal P6 3 crystal structure of La 6 Pd 0.5 CuSi 2 S 14 . This suggests that it is possible to form mixed metal systems which could further enhance NLO properties by incorporation of additional structural distortions.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Probing transport energies and defect states in organic semiconductors using energy resolved electrochemical impedance spectroscopy

Abstract Determining the relative energies of transport states in organic semiconductors is critical to understanding the properties of electronic devices and in designing device stacks. Futhermore, defect states are also highly important and can greatly impact material properties and device performance. Recently, energy‐resolved electrochemical impedance spectroscopy (ER‐EIS) is developed to probe both the ionization energy (IE) and electron affinity (EA) as well as sub‐bandgap defect states in organic semiconductors. Herein, ER‐EIS is compared to cyclic voltammetry (CV) and photoemission spectroscopies for extracting IE and EA values, and to photothermal deflection spectroscopy (PDS) for probing defect states in both polymer and molecular organic semiconductors. The results show that ER‐EIS determined IE and EA are in better agreement with photoemission spectroscopy measurements as compared to CV for both polymer and molecular materials. Furthermore, the defect states detected by ER‐EIS agree with sub‐bandgap features detected by PDS. Surprisingly, ER‐EIS measurements of regiorandom and regioregular poly(3‐hexylthiophene) (P3HT) show clear defect bands that occur at significantly different energies. In regioregular P3HT the defect band is near the edge of the occupied states while it is near the edge of the unoccupied states in regiorandom P3HT.

14 SOLAR ENERGY↗
NASA NTRS1986

Advanced optical smoke meters for jet engine exhaust measurement

Smoke meters with increased sensitivity, improved accuracy, and rapid response are needed to measure the smoke levels emitted by modern jet engines. The standard soiled tape meter in current use is based on filtering, which yields long term averages and is insensitive to low smoke levels. Two new optical smoke meter techniques that promise to overcome these difficulties have been experimentally evaluated: modulated transmission (MODTRAN) and photothermal deflection spectroscopy (PDS). Both techniques are based on light absorption by smoke, which is closely related to smoke density. They are variations on direct transmission measurements which produce a modulated signal that can be easily measured with phase sensitive detection. The MODTRAN and PDS techniques were tested on low levels of smoke and diluted samples of NO2 in nitrogen, simulating light adsorption due to smoke. The results are evaluated against a set of ideal smoke meter criteria that include a desired smoke measurement range of 0.1 to 12 mg cu.m. (smoke numbers of 1 to 50) and a frequency response of 1 per second. The MODTRAN instrument is found to be inaccurate for smoke levels below 3 mg/cu.m. and is able to make a only about once every 20 seconds because of its large sample cell. The PDS instrument meets nearly all the characteristics of an ideal smoke meter: it has excellent sensitivity over a range of smoke levels from 0.1 to 20 mg/cu.m. (smoke numbers of 1 to 60) and good frequency response (1 per second).

Pitz, R. W.↗
NASA NTRS2011

An Ontology Driven Information Architecture for Interoperable Disparate Data Sources

The mission of the Planetary Data System is to facilitate achievement of NASA's planetary science goals by efficiently collecting, archiving, and making accessible digital data produced by or relevant to NASA's planetary missions, research programs, and data analysis programs. The vision is: (1) To gather and preserve the data obtained from exploration of the Solar System by the U.S. and other nations (2) To facilitate new and exciting discoveries by providing access to and ensuring usability of those data to the worldwide community (3) To inspire the public through availability and distribution of the body of knowledge reflected in the PDS data collection PDS is a federation of heterogeneous nodes including science and support nodes

planetary data systems↗
NASA NTRS2011

The Next Generation of Mars-GRAM and Its Role in the Autonomous Aerobraking Development Plan

The Mars Global Reference Atmospheric Model (Mars-GRAM) is an engineering-level atmospheric model widely used for diverse mission applications. Mars-GRAM 2010 is currently being used to develop the onboard atmospheric density estimator that is part of the Autonomous Aerobraking Development Plan. In previous versions, Mars-GRAM was less than realistic when used for sensitivity studies for Thermal Emission Spectrometer (TES) MapYear=0 and large optical depth values, such as tau=3. A comparison analysis has been completed between Mars-GRAM, TES and data from the Planetary Data System (PDS) resulting in updated coefficients for the functions relating density, latitude, and longitude of the sun. The adjustment factors are expressed as a function of height (z), Latitude (Lat) and areocentric solar longitude (Ls). The latest release of Mars-GRAM 2010 includes these adjustment factors that alter the in-put data from MGCM and MTGCM for the Mapping Year 0 (user-controlled dust) case. The greatest adjustment occurs at large optical depths such as tau greater than 1. The addition of the adjustment factors has led to better correspondence to TES Limb data from 0-60 km as well as better agreement with MGS, ODY and MRO data at approximately 90-135 km. Improved simulations utilizing Mars-GRAM 2010 are vital to developing the onboard atmospheric density estimator for the Autonomous Aerobraking Development Plan. Mars-GRAM 2010 was not the only planetary GRAM utilized during phase 1 of this plan; Titan-GRAM and Venus-GRAM were used to generate density data sets for Aerobraking Design Reference Missions. These data sets included altitude profiles (both vertical and along a trajectory), GRAM perturbations (tides, gravity waves, etc.) and provided density and scale height values for analysis by other Autonomous Aero-braking team members.

Justh, Hilary L.↗
NASA NTRS2006

Probabilistic Prediction of Lifetimes of Ceramic Parts

ANSYS/CARES/PDS is a software system that combines the ANSYS Probabilistic Design System (PDS) software with a modified version of the Ceramics Analysis and Reliability Evaluation of Structures Life (CARES/Life) Version 6.0 software. [A prior version of CARES/Life was reported in Program for Evaluation of Reliability of Ceramic Parts (LEW-16018), NASA Tech Briefs, Vol. 20, No. 3 (March 1996), page 28.] CARES/Life models effects of stochastic strength, slow crack growth, and stress distribution on the overall reliability of a ceramic component. The essence of the enhancement in CARES/Life 6.0 is the capability to predict the probability of failure using results from transient finite-element analysis. ANSYS PDS models the effects of uncertainty in material properties, dimensions, and loading on the stress distribution and deformation. ANSYS/CARES/PDS accounts for the effects of probabilistic strength, probabilistic loads, probabilistic material properties, and probabilistic tolerances on the lifetime and reliability of the component. Even failure probability becomes a stochastic quantity that can be tracked as a response variable. ANSYS/CARES/PDS enables tracking of all stochastic quantities in the design space, thereby enabling more precise probabilistic prediction of lifetimes of ceramic components.

Nemeth, Noel N.↗
NASA NTRSDate not supplied

Lunar Science Investigations and Exploration in Celestial Mapping System

Introduction: As NASA expands the mission portfolio on the lunar surface, there is a need for applications with a broad range of analytical and functional capabilities that can be simultaneously deployed onto multiple mobile and desktop platforms to perform in-situ operations and hence enabling extensive Lunar exploration. Celestial Mapping System (CMS) [1,2] is developed to address the need for tools for science investigations, mission planning, operations and support for planetary sciences. Built on top of NASA WorldWind libraries, CMS can be simultaneously deployed onto multiple platforms, has the flexibility to update to the latest imagery and terrain datasets as they are being acquired (in real time) before and/or during the exploration mission and has the potential to enable traverse path planning suited for rovers, EVA and surface mobility units. It can provide critical functionalities such as equipment planning and optimized placement on Lunar surface, line of sight analysis to inform the coverage area for various equipment, powerful measurement tools based on 3D terrain, 3D COLLADA models to represent rovers, humans and equipment, visualization of derived mapping products (e.g. resource maps), and a data engine for hosting new observations that are not available in other contemporary lunar data tools [1]. Visualization of PSRs: The current presentation focuses on the work performed by the authors, to consume a unique dataset of super-enhanced images of the permanently shadowed regions (PSRs) at the lunar poles which were produced by the Hyper-effective nOise Removal U-net Software (HORUS) tool [3]. This tool was developed in direct support of NASA's VIPER and Artemis programs to enhance the extremely low-light images of the interior of PSRs and provide the first-time ability to see within these regions at and discern surface features (i.e. boulders and craters) down to 3 meters in size. We focused on the region near Nobili crater near Lunar south pole, selected site for VIPER mission and stitched several images to create a high-resolution map within one of the PSR of Nobile crater. Line of Sight Analysis and Traverse Planning in PSRs: We have developed an in-built line of sight analysis (LOS) tool in CMS that analyzes the terrain profile and obstructions and provides the visibility of a given terrain for a remote observer. This tool was utilized to perform viewshed analysis to investigate the area inside the PSR, a remote observer such as a rover could see without actually crossing the region. Figure 1 shows the viewshed analysis on the PSR in Nobile region. The yellow pin shows the observer location outside the PSR. The yellow area shows the visible part of PSR. The obstructed area with no visibility for the observer is shown in red. Figure 1: (left) PSR image on top of a high-resolution mosaic of sunlit images of a crater, in Nobile region (right) Viewshed Analysis of the same PSR with observer location shown by yellow pin. This analysis was extended further to set different heights for various observers and then perform the viewshed analysis. Combining the different visibility profiles can help designing improved traverses within the crater. Future plans: Eventually, HORUS datasets will be integrated into CMS as a layer in selected lunar polar regions. Hazard Maps will then be created based on terrain analysis in those regions. This integration will enable multiple scientific and exploration applications, such as designing traverses within PSRs, analyzing potential landing and science mission targets, investigating the meter-scale geomorphology of PSRs, including craters, boulder, surface roughness, mass wasting features and other indications of the presence of water-ice and other volatiles. Acknowledgments: CMS developers team including Kaitlyn J. Dickinson, Tyler A. Lucarz, Tyler W. Choi from USRA, NASA WorldWind Advisory team including Mark Peterson and Guillermo Miguel Del Castillo, HORUS team member V.T. Bickel, Robinson, M., LRO MOON LROC 2 EDR V1.0, LRO-L-LROC-2-EDR-V1.0, NASA Planetary Data System (PDS), 2009. https://doi.org/10.17189/1520643 References: [1] https://celestial.arc.nasa.gov [2] Agrawal et. al. “Celestial Mapping System for Lunar Surface Mapping and Analytics”, Lunar Surface Innovation Consortium, 2021 [3] Bickel V. et al. (2021) Nat Commun 12, 5607

Lunar Mapping↗
NASA NTRS1997

Planetary Data System Spaceborne Thermal Data Sub-Node of the Geosciences Node

The objectives of this proposal were: (1) to assemble the existing spacecraft thermal-infrared data and to place these data into a uniform format as specified by the PDS; (2) to develop a standardized software package, user interface, and catalog database to support the access and analysis of existing and planned thermal infrared datasets in order to provide wide community access to these data; (3) to support the distribution of Thermal SubNode data to users as requested; (4) to incorporate future spacecraft thermal observations into the Thermal SubNode; and (5) to sponsor workshops on the applications of Thermal SubNode data.

Christensen, Philip R.↗
NASA NTRS1998

Clementine High Resolution Camera Mosaicking Project: CL 6003; 0 deg N to 80 deg N Latitude, 30 deg E to 60 deg E Longitude - Volume 3

This compact disk (CD) is part of the Malin Space Science Systems (MSSS) effort to mosaic Clementine I high resolution (HiRes) camera lunar images. These mosaics were developed through calibration and semi-automated registration against the recently released geometrically and photometrically controlled Ultraviolet/Visible (UV/Vis) Basemap Mosaic, which is available through the PDS, as CD-ROM volumes CL_3001-3015. The HiRes mosaics are compiled from non-uniformity corrected, 750 nanometer ("D") filter high resolution observations from the HiRes imaging system onboard the Clementine Spacecraft. These mosaics are spatially warped using the sinusoidal equal-area projection at a scale of 20 m/pixel. The geometric control is provided by the 100 m/pixel U.S. Geological Survey (USGS) Clementine Basemap Mosaic compiled from the 750 nm Ultraviolet/Visible Clementine imaging system. Calibration was achieved by removing the image nonuniformity largely caused by the HiRes system's light intensifier. Also provided are offset and scale factors, achieved by a fit of the HiRes data to the corresponding photometrically calibrated UV/Vis basemap that approximately transform the 8-bit HiRes data to photometric units. The mosaics on this CD were compiled from sub-polar data (latitudes 80 degrees South to 80 degrees North; -80 to +80) within the longitude range 0-30 deg E. The mosaics are divided into tiles that cover approximately 1.75 degrees of latitude and span the longitude range of the mosaicked frames. Images from a given orbit are map projected using the orbit's nominal central latitude. This CD contains ancillary data files that support the HiRes mosaic. These files include browse images with UV/Vis context stored in a Joint Photographic Experts Group (JPEG) format, index files ('imgindx.tab' and 'srcindx.tab') that tabulate the contents of the CD, and documentation files. For more information on the contents and organization of the CD volume set refer to the "FILES, DIRECTORIES AND DISK CONTENTS" section of this document. The image files are organized according to NASA's Planetary Data System (PDS) standards. An image file (tile) is organized as a PDS labeled file containing an "image object".

Malin, Michael↗
DOE OSTI2023

Polythiophene-based terpolymers with modulated aggregation behaviors for high-performance organic solar cells with 16.6% efficiency

Polythiophenes (PTs) are an attractive class of polymer donors (PDs) for organic solar cells (OSCs) owing to their relatively simple structures and scalable synthesis. Herein, a series of chlorinated thiazole-incorporated PT terpolymers are designed and high-performance OSCs with a power conversion efficiency (PCE) of 16.6% are demonstrated. By incorporating two different units, 3,3'-difluoro-2,2'-bithiophene (T2F2) and thieno[3,2-b]thiophene (TT), the aggregation properties of the terpolymers (PTz-FX; X = 0, 30, 50, 70, and 100, where X represents the mole percentage of T2F2 to total T2F2 +TT) are modulated. Among the PTz-FX series, PTz-F70 is found to be the optimal P D because its suitably tuned aggregation property leads to an optimized blend morphology with well-developed crystalline structures and donor–acceptor intermixed domains. The balanced morphology not only promotes charge generation/transport but also suppresses charge recombination in OSC devices. Thus, the PTz-F70-based OSCs achieve the highest PCE (16.6%), outperforming the OSCs based on PTz-FX with extremely strong (PTz-F100, PCE = 14.7%) or weak (PTz-F0, PCE = 12.0%) aggregation properties. The PCE of the PTz-F70-based OSCs is one of the highest performances among PT-based binary OSCs. Finally, this study highlights the importance of controlling the aggregation property of PTs for achieving high-performance PT-based OSCs.

14 SOLAR ENERGY↗
DOE OSTI2021

The Chemical Inventory of the Planet-hosting Disk PDS 70

As host to two accreting planets, PDS 70 provides a unique opportunity to probe the chemical complexity of atmosphere-forming material. We present ALMA Band 6 observations of the PDS 70 disk and report the first chemical inventory of the system. With a spatial resolution of 0."4–0."5 (~50 au), 12 species are detected, including CO isotopologs and formaldehyde, small hydrocarbons, HCN and HCO{sup +} isotopologs, and S-bearing molecules. SO and CH{sub 3}OH are not detected. All lines show a large cavity at the center of the disk, indicative of the deep gap carved by the massive planets. The radial profiles of the line emission are compared to the (sub)millimeter continuum and infrared scattered light intensity profiles. Different molecular transitions peak at different radii, revealing the complex interplay between density, temperature, and chemistry in setting molecular abundances. Column densities and optical depth profiles are derived for all detected molecules, and upper limits obtained for the nondetections. Excitation temperature is obtained for H{sub 2}CO. Deuteration and nitrogen fractionation profiles from the hydrocyanide lines show radially increasing fractionation levels. Comparison of the disk chemical inventory to grids of chemical models from the literature strongly suggests a disk molecular layer hosting a carbon-to-oxygen ratio C/O > 1, thus providing for the first time compelling evidence of planets actively accreting high C/O ratio gas at present time.

74 ATOMIC AND MOLECULAR PHYSICS↗
NASA NTRS1984

Characteristics of the MSFC, PDS microdensitometer

The results of several parametric studies carried out on the Marshall Space Flight Center (MSFC) Photometric Data System PDS-10 microdensitometer are summarized for the purposes of documenting the operation and limitations of the system for inhouse research and to provide a bench mark for comparison with other microdensitometers. The results are grouped into four general areas. These are: (1) system overall stability to drift, (2) photometric linearity and noise, (3) reproducibility, and (4) scanning performance. Test data taken in order to evaluate the interdependency of scan speed, noise and position are included. Shown also are results of tests for system stability, reproducibility, stray light and PMT settling time.

Fountain, W. F.↗
NASA NTRS1996

Grant Proposal for the Continuation of the Voyager Interstellar Mission: LECP Investigation

This proposal documents the plans of the Low Energy Charged Particle (LECP) investigation team for participation in NASA's Voyager Interstellar Mission (VIM) as the Voyager 1 and 2 spacecraft explore the outer reaches of the heliosphere and search for the termination shock and the heliopause. The proposal covers the four year period from 1 January 1997 to 31 December 2000. The LECP instruments on Voyager 1 and 2 measure in situ intensities of charged particles with energies from about 30 keV to 100 MeV for ions, and about 20 keV to greater than 10 MeV for electrons. The instruments provide detailed spectral, angular, and compositional information about the particles. Composition is available for greater than 200 keV/nuc using multi-parameter measurements. Angular information is obtained by a mechanically scanned platform that rotates at various commanded rates. Measurements of low energy ion and electron intensities versus time and spatial location within the heliosphere contain an abundance of information regarding various transport and acceleration processes on both local (approx. 1 hr, approx. 0.01 AU) and global (approx. 11 yrs, approx. 100 AU) scales. The LECP instruments provide unique observations of such dynamical processes, and we anticipate that it will return critical information regarding the boundaries of the heliosphere. Several recent and exciting discoveries based on LECP measurements emphasize the important role that low energy charged particle distributions play in physical processes in the interplanetary medium. Yet, at the same time, these discoveries also underscore the fact that our understanding of processes in the outer heliosphere is, in most cases, incomplete, and in others, only rudimentary at best. Among the discoveries referred to above are the following: (1) Shocks: Examination of greater than 30 keV ion intensities have revealed: (a) a total absence of acceleration beyond only -100-200 keV at a strong transient shock in May 1991 at 35 AU, despite an enhanced level of seed particles; (b) a large transient shock in September 1991 of global scale, with intensities of shock-accelerated ions greater than or equal to 30 keV to approx. 30 MeV showing complex, highly energy-dependent spatial evolution, and small-scale (approx. few gyroradii), often anisotropic, micro-structures; (c) recurrent intensity increases in greater than or equal to 30 keV to -few MeV ions, with structures that, in some cases, show no correlation with the associated corotating shock. (2) Superthermal ion pressure: A global merged interaction region with a leading shock, downstream of which the superthermal ion (greater than or equal to 30 keV to approx. 4 MeV) pressure is comparable to that of the thermal plasma, and the total particle pressure yields a plasma beta of order unity. (3) Pickup ions: Measurements of the C/O ratio within transient structures at 35-45 AU showing the first clear evidence that transient shocks can pre-accelerate interstellar pickup ions from approx. 1 keV/nuc to at least 1 MeV/nuc. (4) Seed particles: Injection of ions for acceleration to high energies at the termination shock is unlikely to be a problem, since interplanetary transient and recurrent shocks are continually accelerating ions, of solar wind or interstellar origin, to highly superthermal energies. (5) Precursor electrons: Ambient solar electrons (greater than or equal to few tens of keV) that exist in the outer heliosphere ca form a broad precursor, several days wide, that is upstream of the termination shock and potentially observable a few months prior to the shock crossing. (6) Solar wind velocity at Voyager 1: We can use LECP ion data to obtain the solar wind velocity at Voyager 1, enabling us to provide critical measurement of the plasma flow as we approach and encounter the termination shock and other regions (necessary due to the partial failure of the Voyager 1 PLS experiment). The work of the LECP investigator team during the VIM will include: (1) Continuing operations with regard to the receipt, processing, verification, cataloging, display, and distribution of the data from the LECP instruments on Voyager 1 and 2, (2) Monitoring the health and performance of the LECP instruments, and evaluating and characterizing the response of the LECP instruments to various energetic particle and plasma environments, (3) Participating in, and supporting Voyager Project planning exercises and other coordinated activities relevant to exploration of the outer heliosphere, (4) Developing analysis techniques and operational procedures suitable for searching for and characterizing the boundaries and unique regions of the outher heliosphere, (5) Continuing the preparation of data sets appropriate for submission to the National Space Sciences Data Center (NSSDC) and, where appropriate, the Planetary Data System (PDS), (6) Maintaining direct Web access to online LECP data through the JHU/APL Voyager LECP home page, (7) Performing scientific evaluations of the Voyager 1 and 2 LECP data sets in conjunction with other data sets and other investigators, with particular focus on the outer regions of the heliosphere, and (8) Publishing the results of these evaluations in the scientific literature and presenting the results in scientific conferences.

Krimigis, Stamatios M.↗
NASA NTRS1976

Apollo 16 far-ultraviolet imagery and spectra of the Large Magellanic Cloud

The Large Magellanic Cloud was observed by the far ultraviolet camera spectrograph from the lunar surface during the Apollo 16 mission 22 April 1972. Images were obtained with about 3 arc min resolution, in the 1,050 to 1,600 and 1,250 to 1,600 A wavelength ranges, of nearly the entire LMC. Spectra were also obtained in the 1,050 to 1,600 and 900 to 1,600 A ranges along a strip 1/4 deg wide (determined by the instrument's grid collimator) passing across the LMC. The images and spectra have been scanned with a PDS microdensitometer, and isodensity contour plots have been prepared using the Univac 1108 computer.

Page, T.↗
NASA NTRS1984

Diagnosing a PDS microdensitometer

A number of diagnostic tests are developed for the Photometric Data System PDS 2020G microdensitometer to monitor its performance and to isolate various electromechanical problems. A number of tests which help to diagnose problems with the photometer, positional accuracy and data collection are described. The tests include: (1) scanning a razor blade edge to study the response of the photometer and zero point losses in the coordinate system, (2) scanning a long straight line to evaluate the drunkness of the stage motions, (3) scanning photometric step wedge calibrations to study the response of the photometer, and (4) measurement of a series of high signal to noise plates of the same region of the sky to evaluate the overall performance of the microdensitometer. A variety of electronic tests to isolate electromechanical problems are also performed.

Vanaltena, W.↗
NASA NTRS1990

Flight motor set 360L002 (STS-27R). Volume 5: Nozzle component

A review of the performance and post-flight condition of the STS-27 Redesigned Solid Rocket Motor (RSRM) nozzles is presented. Thermal/Structural instrumentation data is reviewed, and applicable Discrepancy Reports (DRs) and Process Departures (PDs) are presented. The Nozzle Component Program Team (NCPT) performance evaluation and the Redesign Program Review Board (RPRB) assessment is included. The STS-27 nozzle assemblies were flown on the RSRM Second Flight (Space Shuttle Atlantis) on 2 December 1988. The nozzles were a partially submerged convergent and/or divergent movable design with an aft pivot point flexible bearing. The nozzle assemblies incorporated the following features: RSRM forward exit cone with snubber assembly, RSRM fixed housing, Structural backup Outer Boot Ring (OBR), RSRM cowl ring, RSRM nose inlet assembly, RSRM throat assembly, RSRM aft exit cone assembly with Linear-Shaped Charge (LSC), RTV backfill in Joints 1, 3, and 4, Use of EA913 NA adhesive in place of EA913 adhesive, Redesigned nozzle plug, and Carbon Cloth Phenolic (CCP) with 750 ppm sodium content. The CCP material usage for the STS-27 forward nozzle and aft exit cone assemblies is shown.

Meyer, S. A.↗
NASA NTRS2003

MGS/TES-Odyssey/THEMIS-IR Analysis of Localized Low Albedo Regions in Valles Marineris

We are conducting a systematic analysis of small (approximately 10's of km), localized regions in Valles Marineris that display significant albedo differences relative to their surroundings. This analysis is based on a finding that the locations of the hematite deposits identified by [1] in the interior layered deposits of Valles Marineris typically coincide with regions having a low MGS/TES visible bolometric albedo [1,2]. Until recently, it was difficult to identify the morphology or geologic context of the regions containing the hematite deposits. However, with the recent advent of high-resolution (1/128 /pixel) MOLA grided topography and Mars Odyssey s THEMIS-IR instrument, it has been possible to better understand the morphologic context of TES observations. This analysis combines the use of PDS-released data from the MGS/TES visible bolometer and infrared spectrometer, the Odyssey/THEMIS Infrared imager, and MOLA grided topography. First, the TES infrared bolometer is used to identify regions of interesting albedo variability, and is overlaid on Viking controlled photomosaics for context. THEMIS-IR data, in conjunction with MOLA topography, is then used to: 1) identify the context and morphology of the area; and 2) identify spectrally unique regions at the km scale. In preparation for the latter, all the THEMIS planes are coregistered using an autocorrelation routine, the data are converted to brightness temperature and then each plane is normalized to the brightness temperature of the third plane (1261 cm-1). We then perform a 3-band search for color variations and a Principle Components Analysis (PCA) of the 8 unique bands in the THEMIS-IR dataset. Any variability is then investigated using both THEMIS-IR and TES spectra of the same regions. In both cases, the spectra are ratioed to near-simultaneously acquired spectra of adjacent or "average" regions that do not show this albedo variation, therefore allowing us to identify spectral variability unique to the area of interest. This procedure also allows us to account for calibration problems in THEMIS-IR data, and for any atmospheric effects in both the THEMIS-IR and the TES data.

E Z Noe Dobrea↗