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NASA NTRS2009

Spreadsheets for Analyzing and Optimizing Space Missions

XCALIBR (XML Capability Analysis LIBRary) is a set of Extensible Markup Language (XML) database and spreadsheet- based analysis software tools designed to assist in technology-return-on-investment analysis and optimization of technology portfolios pertaining to outer-space missions. XCALIBR is also being examined for use in planning, tracking, and documentation of projects. An XCALIBR database contains information on mission requirements and technological capabilities, which are related by use of an XML taxonomy. XCALIBR incorporates a standardized interface for exporting data and analysis templates to an Excel spreadsheet. Unique features of XCALIBR include the following: It is inherently hierarchical by virtue of its XML basis. The XML taxonomy codifies a comprehensive data structure and data dictionary that includes performance metrics for spacecraft, sensors, and spacecraft systems other than sensors. The taxonomy contains >700 nodes representing all levels, from system through subsystem to individual parts. All entries are searchable and machine readable. There is an intuitive Web-based user interface. The software automatically matches technologies to mission requirements. The software automatically generates, and makes the required entries in, an Excel return-on-investment analysis software tool. The results of an analysis are presented in both tabular and graphical displays.

Some, Raphael R.↗
NASA NTRS2010

The CEOS WGISS Atmospheric Composition Portal

Goal: Demonstrate the feasibility of connecting distributed atmospheric composition data and analysis tools into a common and shared web framework. Initial effort focused on: a) Collaboratively creating a web application within WDC-RSAT for comparison of satellite derived atmospheric composition datasets accessed from distributed data sources. b) Implementation of data access and interoperability standards. c) Sollicit feedback from paternal users; Especially from ACC participants.

Lynnes, Chris↗
NASA NTRS2001

Alendronate and Resistive Exercise Countermeasures Against Bed Rest-Induced Bone Loss: Biochemical Markers of Bone and Calcium Metabolism

Weightlessness-induced bone loss must be counteracted to ensure crew health during extendedduration space missions. Studies were conducted to assess two bone loss countermeasures in a ground-based model: horizontal bed rest. Following a 3-wk ambulatory adaptation period, male and female subjects (aged 21-56 y) completed a 17-wk bed rest protocol. Subjects were assigned to one of three treatments: alendronate (ALEN; 10 mg/d, n=6), resistive exercise (RE; 1.5 h/d, 6 d/wk, n=8), or control (CN; no countermeasure, n=8). Dietary intake was adjusted to maintain body weight. Endocrine and biochemical indices were measured in blood and urine using standard laboratory methods. All data reported are expressed as percent change from individual pre-bedrest data. Serum calcium changed little during bed rest, and tended to decrease (4-8%) in ALEN subjects. In RE subjects, bone alkaline phosphatase and osteocalcin were increased >65 and >30%, respectively, during bed rest, while these were unchanged or decreased in ALEN and CN subjects. Urinary calcium was increased 50% in CN subjects, but was unchanged or decreased in both ALEN and RE groups. Urinary n-telopeptide excretion was increased 40-50% in CN and RE subjects, but decreased 20% in ALEN subjects. Pyridinium crosslink and deoxypyridinoline excretion were increased 20-50% during bed rest. These data suggest that RE countermeasures are effective at increasing markers of bone formation in an analog of weightlessness, while ALEN reduces markers of bone resorption. Counteracting the bone loss of space flight may require both pharmacologic and exercise countermeasures.

Smith, Scott M.↗
NASA NTRS2012

Jason-1 and Jason-2 POD Using GPS

The Jason-2 satellite, launched in June 2008, is the latest follow-on to the successful Jason-1 altimetry satellite mission launched in December 7, 2001. Both, Jason-2 and Jason-1 are equipped with a GPS dual-frequency receiver, a laser retroreflector array, and a DORIS receiver for precise orbit determination (POD). A series of dynamic and reduced-dynamic Jason-2 orbits computed at NASA GSFC, based on GPS-only data and the std0905 standards, have been completed till cy74through cycle 74 using the IGS05 framework. These orbits, now publicly available, have been shown to agree radially at 1 cm RMS with the GSFC std0905 SLR/DORIS orbits and in comparison with orbits produced by JPL, ESA and CNES. In this paper, we describe the implementation of the IGS08 and repro1 framework for the Jason-2 and Jason-1 GPS POD processing with the NASA GSFC GEODYN software. . In our updated GPS POD, ambiguity fixing and updated time variable and static gravity fields. We also evaluate the implementation of non-tidal and degree-1 loading displacement as forward modeling to the tracking stations. Reduced-dynamic versus dynamic orbit differences are used to characterize the remaining force model errors and TRF instability. In particular, we assess their consistency radially and the stability of the altimeter satellite reference frame in the North/South direction as a proxy to assess the consistency of the reference frame.

Melachroinos, Stavros↗
NASA NTRS2012

Solar Thermal Upper Stage Liquid Hydrogen Pressure Control Testing and Analytical Modeling

The demonstration of a unique liquid hydrogen (LH2) storage and feed system concept for solar thermal upper stage was cooperatively accomplished by a Boeing/NASA Marshall Space Flight Center team. The strategy was to balance thermodynamic venting with the engine thrusting timeline during a representative 30-day mission, thereby, assuring no vent losses. Using a 2 cubic m (71 cubic ft) LH2 tank, proof-of-concept testing consisted of an engineering checkout followed by a 30-day mission simulation. The data were used to anchor a combination of standard analyses and computational fluid dynamics (CFD) modeling. Dependence on orbital testing has been incrementally reduced as CFD codes, combined with standard modeling, continue to be challenged with test data such as this.

Olsen, A. D.↗
NASA NTRS2012

Use of MODIS Snow-Cover Maps for Detecting Snowmelt Trends in North America

Research has shown that the snow season in the Northern Hemisphere has been getting shorter in recent decades, consistent with documented global temperature increases. Specifically, the snow is melting earlier in the spring allowing for a longer growing season and associated land-cover changes. Here we focus on North America. Using the Moderate-Resolution Imaging Radiometer (MODIS) cloud-gap-filled standard snow-cover data product we can detect a trend toward earlier spring snowmelt in the approx 12 years since the MODIS launch. However, not all areas in North America show earlier spring snowmelt over the study period. We show examples of springtime snowmelt over North America, beginning in March 2000 and extending through the winter of 2012 for all of North America, and for various specific areas such as the Wind River Range in Wyoming and in the Catskill Mountains in New York. We also compare our approx 12-year trends with trends derived from the Rutgers Global Snow Lab snow cover climate-data record.

Hall, Dorothy K.↗
NASA NTRS2014

Repeatability Modeling for Wind-Tunnel Measurements: Results for Three Langley Facilities

Data from extensive check standard tests of seven measurement processes in three NASA Langley Research Center wind tunnels are statistically analyzed to test a simple model previously presented in 2000 for characterizing short-term, within-test and across-test repeatability. The analysis is intended to support process improvement and development of uncertainty models for the measurements. The analysis suggests that the repeatability can be estimated adequately as a function of only the test section dynamic pressure over a two-orders- of-magnitude dynamic pressure range. As expected for low instrument loading, short-term coefficient repeatability is determined by the resolution of the instrument alone (air off). However, as previously pointed out, for the highest dynamic pressure range the coefficient repeatability appears to be independent of dynamic pressure, thus presenting a lower floor for the standard deviation for all three time frames. The simple repeatability model is shown to be adequate for all of the cases presented and for all three time frames.

Hemsch, Michael J.↗
NASA NTRS2014

Time Synchronization Prototype, Server Upgrade Procedure Support and Remote Software Development

Networks are roadways of communication that connect devices. Like all roadways, there are rules and regulations that govern whatever (information in this case) travels along them. One type of rule that is commonly used is called a protocol. More specifically, a protocol is a standard that specifies how data should be transmitted over a network. The project outlined in this document seeks to implement one protocol in particular, Precision Time Protocol, within the Kennedy Ground Control Subsystem network at Kennedy Space Center. This document also summarizes work completed for server upgrades, remote software developer training and how all three assignments demonstrated the importance of accountability and security.

Computer Science↗
NASA NTRS2015

Are the Clast Lithologies Contained in Lunar Breccia 64435 Mixtures of Anorthositic Magmas

The anorthositic crust of the Moon is often used as the archtypical example of a primary planetary crust. The abundance and purity of anorthosite in the Apollo sample collection and remote sensing data are generally attributed to an early global magma ocean which produced widespread floating plagioclase cumulates (the ferroan anorthosites; FANs. Recent geochronology studies report evidence of young (less than 4.4 Ga) FAN ages, which suggest that either some may not be directly produced from the magma ocean or that the final solidification age of the magma ocean was younger than previous estimates. A greater diversity of anorthositic rocks have been identified among lunar meteorites as compared to returned lunar samples. Granted that these lithologies are often based on small clasts in lunar breccias and therefore may not represent their actual whole rock composition. Nevertheless, as suggested by the abundance of anorthositic clasts with Mg# [Mg/(Mg+Fe)] less than 0.80 and the difficulty of producing the extremely high plagioclase contents observed in Apollo samples and the remote sensing data, modification of the standard Lunar Magma Ocean (LMO) model may be in order. To ground truth mission science and to further test the LMO and other hypotheses for the formation of the lunar crust, additional coordinated petrology and geochronology studies of lunar anorthosites would be informative. Here we report new mineral chemistry and trace element geochemistry studies of thick sections of a composite of FAN-suite igneous clasts contained in the lunar breccia 64435 in order to assess the significance of this type of sample for petrogenetic studies of the Moon. This work follows recent isotopic studies of the lithologies in 64435 focusing on the same sample materials and expands on previous petrology studies who identified three lithologies in this sample and worked on thin sections.

Simon, J. I.↗
NASA NTRS2015

Nearly a Decade of CALIPSO Observations of Asian and Saharan Dust Properties Near Source and Transport Regions

The lidar on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission, makes robust measurements of dust and has generated a length of record that is significant both seasonally and inter-annually. We exploit this record to determine a multi-year climatology of the properties of Asian and Saharan dust, in particular seasonal optical depths, layer frequencies, and layer heights of dust gridded in accordance with the Level 3 data products protocol, between 2006-2015. The data are screened using standard CALIPSO quality assurance flags, cloud aerosol discrimination (CAD) scores, overlying features and layer properties. To evaluate the effects of transport on the morphology, vertical extent and size of the dust layers, we compare probability distribution functions of the layer integrated volume depolarization ratios, geometric depths and integrated attenuated color ratios near the source to the same distributions in the far field or transport region. CALIPSO is collaboration between NASA and Centre National D'études Spatiales (CNES), was launched in April 2006 to provide vertically resolved measurements of cloud and aerosol distributions. The primary instrument on the CALIPSO satellite is the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), a near-nadir viewing two-wavelength polarization-sensitive instrument. The unique nature of CALIOP measurements make it quite challenging to validate backscatter profiles, aerosol type, and cloud phase, all of which are used to retrieve extinction and optical depth. To evaluate the uncertainty in the lidar ratios, we compare the values computed from dust layers overlying opaque water clouds, considered nominal, with the constant lidar ratio value used in the CALIOP algorithms for dust. We also explore the effects of noise on the CALIOP retrievals at daytime by comparing the distributions of the properties at daytime to the nighttime distributions.

Omar, Ali H.↗
NASA NTRS2017

Imaging Systems for Size Measurements of Debrisat Fragments

The overall objective of the DebriSat project is to provide data to update existing standard spacecraft breakup models. One of the key sets of parameters used in these models is the physical dimensions of the fragments (i.e., length, average-cross sectional area, and volume). For the DebriSat project, only fragments with at least one dimension greater than 2 mm are collected and processed. Additionally, a significant portion of the fragments recovered from the impact test are needle-like and/or flat plate-like fragments where their heights are almost negligible in comparison to their other dimensions. As a result, two fragment size categories were defined: 2D objects and 3D objects. While measurement systems are commercially available, factors such as measurement rates, system adaptability, size characterization limitations and equipment costs presented significant challenges to the project and a decision was made to develop our own size characterization systems. The size characterization systems consist of two automated image systems, one referred to as the 3D imaging system and the other as the 2D imaging system. Which imaging system to use depends on the classification of the fragment being measured. Both imaging systems utilize point-and-shoot cameras for object image acquisition and create representative point clouds of the fragments. The 3D imaging system utilizes a space-carving algorithm to generate a 3D point cloud, while the 2D imaging system utilizes an edge detection algorithm to generate a 2D point cloud. From the point clouds, the three largest orthogonal dimensions are determined using a convex hull algorithm. For 3D objects, in addition to the three largest orthogonal dimensions, the volume is computed via an alpha-shape algorithm applied to the point clouds. The average cross-sectional area is also computed for 3D objects. Both imaging systems have automated size measurements (image acquisition and image processing) driven by the need to quickly and accurately measure tens of thousands of debris fragments. Moreover, the automated size measurement reduces potential fragment damage/mishandling and ability for accuracy and repeatability. As the fragment characterization progressed, it became evident that the imaging systems had to be revised. For example, an additional view was added to the 2D imaging system to capture the height of the 2D object. This paper presents the DebriSat project's imaging systems and calculation techniques in detail; from design and development to maturation. The experiences and challenges are also shared.

Shiotani, B.↗
NASA NTRS2017

Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project: Detect and Avoid Display Evaluations in Support of SC-228 Minimum Operational Performance Standards Development

The primary activity for the UAS-NAS Human Systems Integration (HSI) sub-project in Phase 1 was support of RTCA Special Committee 228 Minimum Operational Performance Standards (MOPS). We provide data on the effect of various Detect and Avoid (DAA) display features with respect to pilot performance of the remain well clear function in order to determine the minimum requirements for DAA displays.

detect and avoid↗
NASA NTRS2017

Behavioral Health and Performance Laboratory Standard Measures (BHP-SM)

The Spaceflight Standard Measures is a NASA Johnson Space Center Human Research Project (HRP) project that proposes to collect a set of core measurements, representative of many of the human spaceflight risks, from astronauts before, during and after long-duration International Space Station (ISS) missions. The term "standard measures" is defined as a set of core measurements, including physiological, biochemical, psychosocial, cognitive, and functional, that are reliable, valid, and accepted in terrestrial science, are associated with a specific and measurable outcome known to occur as a consequence of spaceflight, that will be collected in a standardized fashion from all (or most) crewmembers. While such measures might be used to define standards of health and performance or readiness for flight, the prime intent in their collection is to allow longitudinal analysis of multiple parameters in order to answer a variety of operational, occupational, and research-based questions. These questions are generally at a high level, and the approach for this project is to populate the standard measures database with the smallest set of data necessary to indicate further detailed research is required. Also included as standard measures are parameters that are not outcome-based in and of-themselves, but provide ancillary information that supports interpretation of the outcome measures, e.g., nutritional assessment, vehicle environmental parameters, crew debriefs, etc. The project's main aim is to ensure that an optimized minimal set of measures is consistently captured from all ISS crewmembers until the end of Station in order to characterize the human in space. -This allows the HRP to identify, establish, and evaluate a common set of measures for use in spaceflight and analog research to: develop baselines, systematically characterize risk likelihood and consequences, and assess effectiveness of countermeasures that work for behavioral health and performance risk factors. -By standardizing the battery of measures on all crewmembers, it will allow the HRP to evaluate countermeasures that work for one physiological system and ensure another system is not negatively affected. -These measures, named "Standard Measures," will serve as a data repository and be available to other studies under data sharing agreements.

Williams, Thomas J.↗
NASA NTRS2017

Detecting Inter-Annual Variations in the Phenology of Evergreen Conifers Using Long-Term MODIS Vegetation Index Time Series

Long-term observations of vegetation phenology can be used to monitor the response of terrestrial ecosystems to climate change. Satellite remote sensing provides the most efficient means to observe phenological events through time series analysis of vegetation indices such as the Normalized Difference Vegetation Index (NDVI). This study investigates the potential of a Photochemical Reflectance Index (PRI), which has been linked to vegetation light use efficiency, to improve the accuracy of MODIS-based estimates of phenology in an evergreen conifer forest. Timings of the start and end of the growing season (SGS and EGS) were derived from a 13-year-long time series of PRI and NDVI based on a MAIAC (multi-angle implementation of atmospheric correction) processed MODIS dataset and standard MODIS NDVI product data. The derived dates were validated with phenology estimates from ground-based flux tower measurements of ecosystem productivity. Significant correlations were found between the MAIAC time series and ground-estimated SGS (R (sup 2) equals 0.36-0.8), which is remarkable since previous studies have found it difficult to observe inter-annual phenological variations in evergreen vegetation from satellite data. The considerably noisier NDVI product could not accurately predict SGS, and EGS could not be derived successfully from any of the time series. While the strongest relationship overall was found between SGS derived from the ground data and PRI, MAIAC NDVI exhibited high correlations with SGS more consistently (R (sup 2) is greater than 0.6 in all cases). The results suggest that PRI can serve as an effective indicator of spring seasonal transitions, however, additional work is necessary to confirm the relationships observed and to further explore the usefulness of MODIS PRI for detecting phenology.

Ulsig, Laura↗
NASA NTRS2017

Stratospheric Instrusion Catalog: A 10-Year Compilation of Events Identified by using TRACK with NASA's MERRA-2 Reanalysis

Stratospheric intrusions "the introduction of ozone-rich stratospheric air into the troposphere" have been linked with surface ozone air quality exceedances, especially at the high elevations in the western USA in springtime. However, the impact of stratospheric intrusions in the remaining seasons and over the rest of the USA is less clear. A new approach to the study of stratospheric intrusions uses NASA's Goddard Earth Observing System Model (GEOS) model and assimilation products with an objective feature tracking algorithm to investigate the atmospheric dynamics that generate stratospheric intrusions and the different mechanisms through which stratospheric intrusions may influence tropospheric chemistry and surface air quality seasonally over both the western and the eastern USA. A catalog of stratospheric intrusions identified in the MERRA-2 reanalysis was produced for the period 2004-2015 and validated against surface ozone observations (focusing on those which exceed the national air quality standard) and a recent data set of stratospheric intrusion-influenced air quality exceedance flags from the US Environmental Protection Agency (EPA). Considering not all ozone exceedances have been flagged by the EPA, a collection of stratospheric intrusions can support air quality agencies for more rapid identification of the impact of stratospheric air on surface ozone and demonstrates that future operational analyses may aid in forecasting such events. An analysis of the spatiotemporal variability of stratospheric intrusions over the continental US was performed, and while the spring over the western USA does exhibit the largest number of stratospheric intrusions affecting the lower troposphere, the number of intrusions in the remaining seasons and over the eastern USA is sizable. By focusing on the major modes of variability that influence weather in the USA, such as the Pacific North American (PNA) teleconnection index, predicative meteorological patterns associated with stratospheric intrusions and their regional effects on tropospheric ozone were identified. Improved understanding of the connections between large-scale climate variability and local-scale dynamically-driven air quality events may support improved seasonal prediction of such events.

PN↗
NASA NTRS2018

Compensation of Oxygen Transmittance Effects for Proximal Sensing Retrieval of Canopy-Leaving Sun-Induced Chlorophyll Fluorescence

Estimates of Sun-Induced vegetation chlorophyll Fluorescence (SIF) using remote sensing techniques are commonly determined by exploiting solar and/or telluric absorption features. When SIF is retrieved in the strong oxygen (O2) absorption features, atmospheric effects must always be compensated. Whereas correction of atmospheric effects is a standard airborne or satellite data processing step, there is no consensus regarding whether it is required for SIF proximal-sensing measurements nor what is the best strategy to be followed. Thus, by using simulated data, this work provides a comprehensive analysis about how atmospheric effects impact SIF estimations on proximal sensing, regarding: (1) the sensor height above the vegetated canopy; (2) the SIF retrieval technique used, e.g., Fraunhofer Line Discriminator (FLD) family or Spectral Fitting Methods (SFM); and (3) the instrument's spectral resolution. We demonstrate that for proximal-sensing scenarios compensating for atmospheric effects by simply introducing the O2 transmittance function into the FLD or SFM formulations improves SIF estimations. However, these simplistic corrections still lead to inaccurate SIF estimations due to the multiplication of spectrally convolved atmospheric transfer functions with absorption features. Consequently, a more rigorous oxygen compensation strategy is proposed and assessed by following a classic airborne atmospheric correction scheme adapted to proximal sensing. This approach allows compensating for the O2 absorption effects and, at the same time, convolving the high spectral resolution data according to the corresponding Instrumental Spectral Response Function (ISRF) through the use of an atmospheric radiative transfer model. Finally, due to the key role of O2 absorption on the evaluated proximal-sensing SIF retrieval strategies, its dependency on surface pressure (p) and air temperature (T) was also assessed. we combined simulated spectral data with p and T measurements obtained for a one-year period in the Hyytiala Forestry Field Station in Finland. Of importance hereby is that seasonal dynamics in terms of T and p, if not appropriately considered as part of the retrieval strategy, can result in erroneous SIF seasonal trends that mimic those of known dynamics for temperature-dependent physiological responses of vegetation.

"sun–induced chlorophyll fluorescence (SIF); pro↗
NASA NTRS2019

Historical (1700–2012) Global Multi-Model Estimates of the Fire Emissions from the Fire Modeling Intercomparison Project (FireMIP)

Fire emissions are critical for carbon and nutrient cycles, climate, and air quality. Dynamic Global Vegetation Models (DGVMs) with interactive fire modeling provide important estimates for long-term and large-scale changes of fire emissions. Here we present the first multi-model estimates of global gridded historical fire emissions for 1700-2012, including carbon and 33 species of trace gases and aerosols. The dataset is based on simulations of nine DGVMs with different state-of-the-art global fire models that participated in the Fire Modeling Intercomparison Project (FireMIP), using the same and standardized protocols and forcing data, and the most up-to-date fire emission factor table from field and laboratory studies over various land cover types. We evaluate the simulations of present-day fire emissions by comparing them with satellite-based products. Evaluation results show that most DGVMs simulate present-day global fire emission totals within the range of satellite-based products, and can capture the high emissions over the tropical savannas, low emissions over the arid and sparsely vegetated regions, and the main features of seasonality. However, most of the models fail to simulate the interannual variability, partly due to a lack of modeling peat fires and tropical deforestation fires. Historically, all models show only a weak trend in global fire emissions before ~1850s, consistent with multi-source merged historical reconstructions. The long-term trends among DGVMs are quite different for the 20th century, with some models showing an increase and others a decrease in fire emissions, mainly as a result of the discrepancy in their simulated responses to human population density change and land-use and land-cover change (LULCC). Our study provides a basic dataset for developing regional and global multi-source merged historical reconstructions and merging methods, and analyzing historical changes of fire emissions and their uncertainties as well as their role in the Earth system. It also highlights the importance of accurately modeling the responses of fire emissions to LULCC and population density change in reducing uncertainties in historical reconstructions of fire emissions and providing more reliable future projections.

Li, Fang↗
NASA NTRS2020

Biases in the In Situ Measurement of Particulate Organic Carbon and Its Effect on the Calibration and Validation of Ocean Color Sensors

Particulate organic carbon (POC) plays an oversize role, relative to its standing stock in the global carbon (C) cycle. Accurate measurement of POC is central to understanding the ocean C flux and its sensitivity to climate forcing. POC is a standard NASA ocean color data product, which lacks a consensus, quality-assured measurement protocol for satellite validation. Thus, algorithms based on field measurements lacking verified uncertainties have limited applicability towards climate data records. Different sampling and filtration protocols, and blank corrections, introduce biases in the magnitude of POC measured from the field. A significant filter blank attributable to dissolved organic C (DOC) adsorption that, until recently has been seldom corrected for, likely has introduced biases in POC global datasets.

Chaves, Joaquín E.↗