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At least 199 records · Page 11

The Mars Reconnaissance Orbiter Mission: 2018 Status

The Mars Reconnaissance Orbiter (MRO) continues its dual-mode mission of scientific exploration and programmatic support. Now in its 13th year of flight (and its 12th year in its low-altitude, sun-synchronous orbit around Mars), the spacecraft continues in its normal flight mode and its science instruments continue to acquire a treasure trove of data which is being used to study the Martian environment (surface, sub-surface, and atmosphere). To date (July 2018), more than 333 TB of scientific data have been returned to Earth. Building onto the 2017 IAC paper: “The Mars Reconnaissance Orbiter Mission: Continuing a Record of Exploration from Mars Orbit,” [1] this paper provides a 2018 status update on the MRO Mission. A signature event since the 2017 writing is the onset and evolution of a planet-encircling dust event (PEDE), the first such event since 2007. Additional recent science highlights for MRO include the discovery of mid-latitude ice cliffs, polar cap characterization, daily global mapping of the 2018 PEDE dust activity and the atmospheric thermal response, further characterization of the tantalizing recurring slope lineae (RSL), and continued detection of surface changes. Programmatically, UHF relay support for the Mars Science Laboratory (MSL) rover Curiosity and the Mars Exploration Rover (MER) rover Opportunity continues at a pace that provides the engineers and scientists operating those surface vehicles timely information to support their mission planning and science analysis. Most of the landing site characterization requests for the NASA Mars 2020 rover and the ESA ExoMars Rover/Surface Platform (RSP) missions have been completed, with final acquisitions delayed due to the obscuring dust haze from the current PEDE. In parallel, the flight team has faced new engineering challenges as the spacecraft has aged. The team has developed and is implementing actions that are aimed at stretching spacecraft battery life. A new all-stellar capability using the spacecraft’s star trackers now allows for normal spacecraft operations without IMUs. In addition to its current relay duties, MRO will be synchronized to provide critical communications support for the InSight Entry, Descent, and Landing (EDL) event on November 26, 2018, and will be readied to support InSight’s critical commissioning phase with UHF relay support and environmental characterization. A new split-pass relay capability has been developed which will allow MRO to relay with two surface vehicles in “close proximity” on the same overflight, i.e. the InSight lander and the Curiosity rover. Extended for another year of operations by NASA, this paper will highlight recent scientific progress and describe actions that will extend MRO’s life well into the 2020’s as a key element of the Mars Exploration Program.

Zurek, Richard W.↗

Ocean Optics Protocols for Satellite Ocean Color Sensor Validation

This document stipulates protocols for measuring bio-optical and radiometric data for the SIMBIOS Project. It supersedes the earlier version, and is organized into four parts: Introductory Background, Instrument Characteristics, Field Measurements and Data Analysis, Data Reporting and Archival. Changes in this revision include the addition of three new chapters: (1) Fundamental Definitions, Relationships and Conventions; (2) MOBY, A Radiometric Buoy for Performance Monitoring and Vicarious Calibration of Satellite Ocean Color Sensors: Measurement and Data Analysis Protocols; and (3) Normalized Water-Leaving Radiance and Remote Sensing Reflectance: Bidirectional Reflectance and Other Factors. Although the present document represents another significant, incremental improvement in the ocean optics protocols, there are several protocols that have either been overtaken by recent technological progress, or have been otherwise identified as inadequate. Revision 4 is scheduled for completion sometime in 2003. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational Project. The contributions are published as submitted, after only minor editing to correct obvious grammatical or clerical errors.

Mueller, James L.↗

Ocean Optics Protocols for Satellite Ocean Color Sensor Validation

This document stipulates protocols for measuring bio-optical and radiometric data for the SIMBIOS Project. It supersedes the earlier version, and is organized into four parts: Introductory Background, Instrument Characteristics, Field Measurements and Data Analysis, Data Reporting and Archival. Changes in this revision include the addition of three new chapters: (1) Fundamental Definitions, Relationships and Conventions; (2) MOBY, A Radiometric Buoy for Performance Monitoring and Vicarious Calibration of Satellite Ocean Color Sensors: Measurement and Data Analysis Protocols; and (3) Normalized Water-Leaving Radiance and Remote Sensing Reflectance: Bidirectional Reflectance and Other Factors. Although the present document represents another significant, incremental improvement in the ocean optics protocols, there are several protocols that have either been overtaken by recent technological progress, or have been otherwise identified as inadequate. Revision 4 is scheduled for completion sometime in 2003. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational Project. The contributions are published as submitted, after only minor editing to correct obvious grammatical or clerical errors.

Mueller, James L.↗

NASA's upper atmosphere research satellite: A program to study global ozone change

The Upper Atmosphere Research Satellite (UARS) is a major initiative in the NASA Office of Space Science and Applications, and is the prototype for NASA's Earth Observing System (EOS) planned for launch in the 1990s. The UARS combines a balanced program of experimental and theoretical investigations to perform diagnostic studies, qualitative model analysis, and quantitative measurements and comparative studies of the upper atmosphere. UARS provides theoretical and experimental investigations which pursue four specific research topics: atmospheric energy budget, chemistry, dynamics, and coupling processes. An international cadre of investigators was assembled by NASA to accomplish those scientific objectives. The observatory, its complement of ten state of the art instruments, and the ground system are nearing flight readiness. The timely UARS program will play a major role in providing data to understand the complex physical and chemical processes occurring in the upper atmosphere and answering many questions regarding the health of the ozone layer.

Luther, Michael R.↗

Advanced Research Directions on AI for Science, Energy, and Security: Report on Summer 2022 Workshops

Over the past decade, fundamental changes in artificial intelligence (AI)—from foundational to applied—have delivered dramatic insights across a wide breadth of U.S. Department of Energy (DOE) mission space. AI is helping to augment and improve scientific and engineering workflows (e.g., for control, design, and dramatic performance gains through surrogate models) in national security, the Office of Science, and DOE’s applied energy programs. The progress and potential for AI in DOE science was captured in the 2020 “AI for Science” report from the DOE laboratory community in collaboration with academia and industry. Specific scientific areas ready to further leverage the power of AI ranged from the scale and performance of computational models to data analysis to creating new classes of observations using computer vision. Since that report, the scale and scope of scientific AI have accelerated, revealing new, emergent properties that yield insights that go beyond enabling opportunities to being potentially transformative in the way that scientific problems are posed and solved. Thus, under the guidance of both the Office of Science (SC) and the National Nuclear Security Administration (NNSA), the DOE national laboratories organized a series of workshops in 2022 to gather input on new and rapidly emerging opportunities and challenges of scientific AI. This 2023 report is a synthesis of those workshops. The scientific community believes AI can have a foundational impact on a broad range of DOE missions, including science, energy, and national security. Further, DOE has unique capabilities that enable the community to drive progress in scientific use of AI, building on long-standing DOE strengths and investments in computation, data, and communications infrastructure, spanning the Energy Sciences Network (ESnet), the Exascale Computing Project (ECP), and integrative programs such as the NNSA Office of Defense Programs Advanced Simulation and Computing (ASC) and the SC Scientific Discovery through Advanced Computing (SciDAC) programs.

97 MATHEMATICS AND COMPUTING↗

Validation of Forested Inundation Extent Revealed by L-Band Polarimetric and Interferometric SAR Data

UAVSAR, NASA's airborne Synthetic Aperture Radar (SAR), conducted an extended observational campaign in Central and South America in March 2013, primarily related to volcanic deformations along the Andean Mountain Range but also including a large number of flights studying other scientific phenomena. During this campaign, the L-Band SAR collected data over the Napo River in Ecuador. The objectives of this experiment were to acquire polarimetric and interferometric L-Band SAR data over an inundated tropical forest in Ecuador simultaneously with on-the-ground field work ascertaining the extent of inundation, and to then derive from this data a quantitative estimate for the error in the SAR-derived inundation extent. In this paper, we will first describe the processing and preliminary analysis of the SAR data. The polarimetric SAR data will be classified by land cover and inundation state. The interferometric SAR data will be used to identify those areas where change in inundation extent occurred, and to measure the change in water level between two observations separated by a week. Second, we will describe the collection of the field estimates of inundation, and have preliminary comparisons of inundation extent measured in the field field versus that estimated from the SAR data.

Synthetic Aperture Radar (SAR),↗

Generating Accurate and Consistent Top-Of-Atmosphere Reflectance Products from the New Generation Geostationary Satellite Sensors

GeoNEX is a collaborative project by scientists from NASA, NOAA, JAXA, and other organizations around the world with the purpose of generating a suite of Earth-monitoring products using data streams from the latest geostationary (GEO) sensors including the GOES-16/17 ABI and the Himawari-8/9 AHI. An accurate and consistent top-of-atmosphere (TOA) reflectance product, in particular the bidirectional reflectance factor (BRF), is the starting point in the scientific processing chain. We describe the main considerations and corresponding algorithms in generating the GeoNEX TOA BRF product. First, a special advantage of geostationary data streams is their high temporal resolution (~10 minutes per full-disk scan), providing a key source of information for many downstream products. To fully utilize this high temporal frequency demands a high georegistration accuracy for every acquired image. Our analysis shows that there can be substantial georegistration uncertainties in both GOES and Himawari L1b data which we addressed by implementing a phase-based correction algorithm to remove residual errors. Second, geostationary sensors have distinct illumination-view geometry features in that the solar angle changes for every pixel. Therefore, to accurately derive a BRF requires a solar position algorithm and the estimation of the pixel-wise acquisition time within an uncertainty of 10 seconds. Third, we discuss the measures we adopted to check and correct residual radiometric calibration issues of individual sensors to enable time-series analysis as well as the cross calibration between different satellite sensors (including those from low-Earth orbit). Finally, we also explain the rationale for the choice of the global grid/tile system of the GeoNEX TOA BRF product.

Wang, Weile↗

Adaptive elasticity policies for staging-based in situ visualization

In situ processing aims to alleviate the growing gap between computation and I/O capabilities by performing data processing close to the data source. In situ processing is widely used to process data generated by multiple data sources, including observation data from edge devices or scientific observational facilities and the simulation data generated by scientific computation on a high-performance computing (HPC) platform. For a scientific workflow that is run on an HPC platform and composed of a simulation program and an in situ data analytics or visualization (abbreviated as ana/vis) task, there is an implicit assumption that the computing resources assigned to the workflow keep static during the workflow execution. However, with the converging trend between the HPC and cloud computing platform, running the in situ ana/vis task in an elastic way is promising to decrease its overhead and improve its resource utilization rate. Resource elasticity represents the ability to change resource configurations such as the number of computing nodes/processes during workflow execution. An elastic job may dynamically adjust resource configurations; it may use a few resources at the beginning and more resources toward the end of the job when interesting data appear. However, it is hard to predict a priori how many computing nodes/processes need to be added/removed during the workflow execution to adapt to changing workflow needs. How to efficiently guide elasticity operations, such as growing or shrinking the number of processes used for in situ analysis during workflow execution, is an open-ended research question. In this article, we present adaptive elasticity policies that adopt workflow runtime information collected during workflow execution to predict how to trigger the addition/removal of processes in order to minimize in situ processing overhead. Taking in situ visualization tasks as an example, we integrate the presented elasticity policies into a staging-based elastic workflow and evaluate its efficiency in multiple elasticity scenarios. Compared with the situation without elasticity or with a static elasticity policy that uses a fixed number of processes for each rescaling operation, the adaptive elasticity policy can save overhead in finding a proper resource configuration and improve resource utilization efficiency. Furthermore, one experiment illustrates that the adaptive elasticity policy saves 41% of core-hours compared with the situation without the resource elasticity.

97 MATHEMATICS AND COMPUTING↗

A modERN resource: identification of Drosophila transcription factor candidate target genes using RNAi

Transcription factors (TFs) play a key role in development and in cellular responses to the environment by activating or repressing the transcription of target genes in precise spatial and temporal patterns. In order to develop a catalog of target genes of Drosophila melanogaster TFs, the modERN consortium systematically knocked down the expression of TFs using RNAi in whole embryos followed by RNA-seq. We generated data for 45 TFs which have 18 different DNA-binding domains and are expressed in 15 of the 16 organ systems. The range of inactivation of the targeted TFs by RNAi ranged from log2fold change -3.52 to +0.49. The TFs also showed remarkable heterogeneity in the numbers of candidate target genes identified, with some generating thousands of candidates and others only tens. We present detailed analysis from five experiments, including those for three TFs that have been the focus of previous functional studies (ERR, sens, and zfh2) and two previously uncharacterized TFs (sens-2 and CG32006), as well as short vignettes for selected additional experiments to illustrate the utility of this resource. The RNA-seq datasets are available through the ENCODE DCC (http://encodeproject.org) and the Sequence Read Archive (SRA). TF and target gene expression patterns can be found here: https://insitu.fruitfly.org. These studies provide data that facilitate scientific inquiries into the functions of individual TFs in key developmental, metabolic, defensive, and homeostatic regulatory pathways, as well as provide a broader perspective on how individual TFs work together in local networks during embryogenesis.

59 BASIC BIOLOGICAL SCIENCES↗

Efficient Asynchronous I/O with Request Merging

With the advancement of exascale computing, the amount of scientific data is increasing day by day. Efficient data access is necessary for scientific discoveries. Unfortunately, the I/O performance is not improved, like the CPU and network speed. So, I/O operations take longer time than data generation or analysis. Asynchronous I/O has been proposed to extenuate the I/O bottleneck by overlapping I/O and computation time. However, multiple small write operations can diminish the benefits of asynchronous I/O, as the I/O time becomes significantly longer than the compute time, with little time to overlap with. To overcome these issues, we present an optimization technique to merge small contiguous write operations. We integrated our solution into the HDF5 asynchronous I/O VOL connector and demonstrated the effectiveness of merging HDF5 write operations automatically and transparently without requiring any code change from the application.

Chowdhury, Kamal Hossain↗

Preliminary results of scientific research on biosatellite Kosmos-1129

The first physiological study aimed at deeper examination mechanisms of weightlessness and adaptation/readaptation is described. It dealt with metabolism, support motor changes and nonspecific changes connected with stress reaction. Wistar rats were used in a triple setup: flight/vivarium/biosatellite mockup. Animal condition was assessed on motor activity and body temperature. Extensive tables show weight, blood and enzyme analysis, etc. Animals groups were labeled: stress, behavior, body composition, biorhythm, ontogenesis. The second or biological study dealt with tumorous carrot tissues but humidity control was defective: some indices are reported such as cell membrane permeability, tissue respiration, etc. It also was concerned with a fowl embryogenetic experiment (Japanese quail) but mechanical effects on landing reduced its success. The third study, on radiation dosimetry, presents a little tabulated data but chiefly gives lists of satellite detector units of different kinds and from different countries.

Source record↗

Ocean-Atmosphere Interaction in Climate Changes

The diagram, which attests the El Nino teleconnection observed by the NASA Scatterometer (NSCAT) in 1997, is an example of the results of our research in air-sea interaction - the core component of our three-part contribution to the Climate Variability Program. We have established an interplay among scientific research, which turns spacebased data into knowledge, a push in instrument technology, which improves observations of climate variability, and an information system, which produces and disseminates new data to support our scientific research. Timothy Liu led the proposal for advanced technology, in response to the NASA Post-2002 Request for Information. The sensor was identified as a possible mission for continuous ocean surface wind measurement at higher spatial resolution, and with the unique capability to measure ocean surface salinity. He is participating in the Instrument Incubator Program to improve the antenna technology, and is initiating a study to integrate the concept on Japanese missions. He and his collaborators have set up a system to produce and disseminate high level (gridded) ocean surface wind/stress data from NSCAT and European missions. The data system is being expanded to produce real-time gridded ocean surface winds from Quikscat, and precipitation and evaporation from the Tropical Rain Measuring Mission. It will form the basis for a spacebased data analysis system which will include momentum, heat and water fluxes. The study on 1997 El Nino teleconnection illustrates our interdisciplinary and multisensor approach to study climate variability. The diagram shows that the collapse of trade wind and the westerly wind anomalies in the central equatorial Pacific led to the equatorial ocean warming. The equatorial wind anomalies are connected to the anomalous cyclonic wind pattern in the northeast Pacific. The anomalous warming along the west coast of the United States is the result of the movement of the pre-existing warm sea surface temperature anomalies with the cyclonic wind anomalies toward the coast. The results led to a new study which identifies decadal ocean variations in the Northeast Pacific. Three studies of oceanic responses to wind forcing caused by the seasonal change of monsoons, the passage of a typhoon, and the 1997 El Nino, were successfully conducted. Besides wind forcing, we continue to examine new techniques for estimating thermal and hydrologic fluxes, through the inverse ocean mixed-layer model, through divergence of atmospheric water transport, and by direct retrieval from radiances observed by microwave radiometers. Greenhouse warming has been linked to water vapor measured by two spaceborne sensors in two studies. In the first study, strong baroclinicity and deep convection were found to transport water vapor to the upper atmosphere and increase greenhouse trapping over the storm tracks of the North Pacific and Atlantic. In another study, the annual cycle of greenhouse warming were related to sea surface temperature (SST) and integrated water vapor, and the latitudinal dependence of the magnitudes and phases of the annual cycles were compared.

Liu, W. Timothy↗

Data Analysis of X-ray Panels Used in X-ray CT Scientific Instruments

This report is a follow-up study on M. Skeate’s study on System Drift Detection for Health Monitoring (Skeate, 2023). The following report highlights analyses of the panel’s behavior with extended use. This includes effects of burn-in on the panel from over-use and bad pixels (defined in Methodology.) Using data-forward statistical analyses across a sequence of scans, and given that the other conditions present in the data can be replicated, this study show that overtime use of panels does not affect bad pixel count. Also, I present conclusive evidence of a direct relationship between the regions of the panel that are exposed to radiation and burn-in damage to that region overtime. Additionally, this study also highlights the effect of the duty cycle on the dark current change in the panel.

42 ENGINEERING↗

The Earth Observing System (EOS)

The Earth Observing System is a US National Aeronautics and Space Administration (NASA) program consisting of a science segment, a data system, and a space segment made up of a series of polar-orbiting and mid-inclination satellites for long-term monitoring of the Earth as an integrated system, including observations of the land surface, biosphere, atmosphere, cryosphere, and oceans. Initially conceived in the mid-late 1980s, it was implemented as a series of large "flagship" missions and smaller focused satellites, often in partnership with instruments and sometimes spacecraft from other nations. In 1984 NASA formed several instrument panels to develop concepts for “facility instruments” that would provide comprehensive support to the scientific and applications’ communities, each with a supporting science team competitively selected via peer-review. An Announcement of Opportunity was released in 1988 and proposals were solicited for three types of proposals: (i) instrument investigations that would include the provision of instrumentation for flight on a polar platform, including non-Earth science payloads requiring polar orbits (PI instruments), (ii) research facility instrument team member and team leader investigations for facility instruments, and (iii) interdisciplinary science investigations to provide data analysis and modeling, preparing to use data acquired from the space platforms. The initial selections made in 1989 included support for 24 instrument investigations, 6 research facility instrument investigations, and 28 interdisciplinary investigations. Although considerable changes were made over the years in the structure and orbital configuration of the various instruments and platforms, a total of 10 different missions were eventually flown, as shown in Fig. 1. These included three multiinstrument flagship platforms known as Terra (launched in 1999), Aqua (launched in 2002), and Aura (launched in 2004), where the Terra mission emphasis was primarily on land processes, Aqua on the hydrological cycle, and Aura on atmospheric chemistry. In addition to these flagship missions the EOS missions included Landsat 7 (land cover classification and change), QuikScat (wind speed and direction over the oceans), Jason-1 (ocean surface topography and sea level), ACRIMSAT (total solar irradiance (TSI)), SAGE III (stratospheric aerosol and ozone levels), ICESat (ice, cloud, and land elevation), and SORCE (Solar Radiation and Climate Experiment; total and spectral solar irradiance). In addition EOS supported CERES (an Earth radiation budget sensor) and LIS (a lightning sensor), that flew as part of the NASA/JAXA Tropical Rainfall Measuring Mission (1997), and SeaWinds (wind speed and direction), that flew as part of the short-lived ADEOS II (Midori II, 2002) mission of JAXA (Japan Aerospace Exploration Agency). The EOS contributions are too numerous to present in detail in this article, but can be viewed for convenience as a means of obtaining global measurements (with appropriate characteristics) of the 24 variables and variable groups listed in Table 1. This table was created by the EOS community in the late 1990s as a way to succinctly indicate which instruments on the various EOS platforms were expected to contribute to each of the specified variables in primary (bold), secondary (bold italics), or contributing (roman) roles. All of the science data products produced by these space missions are available without charge throughout the world, and are thus highly valued for their many contributions to applications such as air quality, fires, land cover change, and the state of the oceans, as well as for science and monitoring of the state of the Earth system and its changes over time. These and other international satellites have played a crucial role in understanding and documenting global change, including (i) global surface temperature and atmospheric temperature and water vapor profiles, (ii) glacial retreat, (iii) sea ice extent and change, (iv) solar radiation into and out of the Earth-atmosphere system, (v) atmospheric aerosol and cloud properties, (vi) sources and sinks of

ICESat↗

Composition Reanalyses at NASA’s Global Modeling and Assimilation Office

Scientific Assessments of Ozone Depletion 2018 and 2022 report the recovery of Antarctic ozone, consistent with diminishing concentrations of halogens in the stratosphere. Both the size and the depth of the springtime ozone holes exhibit downward trends, particularly in September. Superimposed on the recovery trend are significant year-to-year fluctuations arising from dynamical variability potentially influenced by climate forcing and volcanic eruptions. Since 2018 the Antarctic stratosphere has experienced a wild parade of austral spring seasons with a sudden stratospheric warming and exceptionally high ozone in 2019 followed by large and long-lasting ozone holes in the following years, prompting questions about the speed and detectability of Antarctic ozone recovery and its potential connections to human-induced climate change. From the Australian New Years’ wildfires of 2020 to volcanic aerosols to the unprecedented injection of water vapor by the Hunga volcanic eruption, recent scientific literature on the subject investigates many factors that may or may not have contributed to this remarkable interannual variability. This presentation summarizes dynamical influences on springtime Antarctic stratospheric ozone in recent years and discusses these results in the context of long-term trends. In particular, this work seeks to isolate dynamical and chemical contributions to the Antarctic springs since 2019 using a consistent methodological framework. Our analysis uses constituent and meteorological fields from the MERRA-2 Stratospheric Composition Reanalysis of Aura MLS (M2-SCREAM) in combination with data from the Atmospheric Chemistry Experiment – Fourier Transform Spectrometer and from ozone sondes. Using the high spatial and temporal resolution of M2-SCREAM, we analyze the daily evolution of southern polar ozone, HCl, N2O, and water vapor in dynamical flow-following coordinates relative to the location, size, and shape of the polar vortex. For vertically integrated stratospheric ozone we emphasize the importance of the wave-influenced geometry of the polar vortex and its vertical alignment. The ultimate purpose of this project is to contribute to the quantification of the speed of the Antarctic ozone recovery and associated uncertainties.

Krzysztof Wargan↗

Scientific Data Analysis and Software Support: Geodynamics

The support on this contract centers on development of data analysis strategies, geodynamic models, and software codes to study four-dimensional geodynamic and oceanographic processes, as well as studies and mission support for near-Earth and interplanetary satellite missions. SRE had a subcontract to maintain the optical laboratory for the LTP, where instruments such as MOLA and GLAS are developed. NVI performed work on a Raytheon laser altimetry task through a subcontract, providing data analysis and final data production for distribution to users. HBG had a subcontract for specialized digital topography analysis and map generation. Over the course of this contract, Raytheon ITSS staff have supported over 60 individual tasks. Some tasks have remained in place during this entire interval whereas others have been completed and were of shorter duration. Over the course of events, task numbers were changed to reflect changes in the character of the work or new funding sources. The description presented below will detail the technical accomplishments that have been achieved according to their science and technology areas. What will be shown is a brief overview of the progress that has been made in each of these investigative and software development areas. Raytheon ITSS staff members have received many awards for their work on this contract, including GSFC Group Achievement Awards for TOPEX Precision Orbit Determination and the Joint Gravity Model One Team. NASA JPL gave the TOPEX/POSEIDON team a medal commemorating the completion of the primary mission and a Certificate of Appreciation. Raytheon ITSS has also received a Certificate of Appreciation from GSFC for its extensive support of the Shuttle Laser Altimeter Experiment.

Klosko, Steven↗

Cosmic Ray Telescope Experiment (CRT), Pioneer 10/11 Program

In May 1996 the electrical power on Pioneer 10 was no longer adequate to support the Cosmic Ray Telescope Experiment (CRT). In March 1997 ground based operations for the mission were terminated. The 25 years of Pioneer 10 were a remarkable voyage of discovery as it ventured into a vast new unexplored region of space. These observations by the Pioneer experiments led in the development of a new discipline of space science - heliospheric physics. For cosmic ray studies it was an incredible era, leading to the identification of new energetic particle populations and processes and initiating the study of the dynamics and large-scale structure and began the study of the dynamics and large-scale structure of the outer heliosphere. A summary of some of the principal scientific findings of the CRT experiment over this period is given in the next section. Even with the cessation of data from the Pioneer 10/11 mission there remained a great deal of scientific analysis and data archiving that required on the order of an additional three years of effort on the part of the CRT team. We have tried to select those tasks where the P10/11 CRT data have an important role to play. Special emphasis is placed on long-term synoptic studies that make use of the extended temporal and spatial coverage of the missions and the full capabilities of the CRT experiment. The major scientific objectives of this study are: (1) A phenomenological study of the modulation process in the heliosphere, thereby laying the foundation for developing a unified model of cosmic ray modulation over a complete 22 year heliomagnetic cycle; (2) These modulation studies and the temporal changes in the cosmic ray intensities also provide information on the large-scale structure and dynamics of the outer heliosphere; (3) use the galactic and anomalous cosmic ray data from Pioneer 10 to obtain a more accurate estimate of the distance to the modulation boundary and to the termination shock; (4) Use the results from (2) and from temporal variations to determine whether significant modulation occurs in the region of the heliosphere; (5)study the acceleration and transport of low energy solar interplanetary energetic particles and their relation to solar activity and interplanetary phenomena.

McDonald, Frank B.↗

The Scientific and Societal Need for Accurate Global Remote Sensing of Marine Suspended Sediments

Population pressure, commercial development, and climate change are expected to cause continuing alteration of the vital oceanic coastal zone environment. These pressures will influence both the geology and biology of the littoral, nearshore, and continental shelf regions. A pressing need for global observation of coastal change processes is an accurate remotely-sensed data product for marine suspended sediments. The concentration, delivery, transport, and deposition of sediments is strongly relevant to coastal primary production, inland and coastal hydrology, coastal erosion, and loss of fragile wetland and island habitats. Sediment transport and deposition is also related to anthropogenic activities including agriculture, fisheries, aquaculture, harbor and port commerce, and military operations. Because accurate estimation of marine suspended sediment concentrations requires advanced ocean optical analysis, a focused collaborative program of algorithm development and assessment is recommended, following the successful experience of data refinement for remotely-sensed global ocean chlorophyll concentrations.

Acker, James G.↗