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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 343 records · Page 19

Defining Navigation Requirements for Future Precision Lander Missions

Human mission concepts for both the Moon and Mars require landing precision capabilities beyond the current state of art. The Safe and Precise Landing Integrated Capabilities Evolution (SPLICE) project leverages previous work at NASA to develop multimission precision landing and hazard avoidance (PL&HA) technologies to meet the advanced landing requirements. SPLICE aims to develop guidance, navigation and control (GN&C) capabilities for both Moon and Mars lander missions. The approach the project is using to identify a standard suite begins with developing a PL&HA requirements matrix to inform technology investments. The approach to develop a multi-mission navigation requirements matrix includes identifying representative concepts of operations for both robotic and human missions. It also identifies navigation sensor options with estimated performance parameters. This paper summarizes the concepts of operations and sensors considered to develop the SPLICE PL&HA requirements matrix. A description of the analysis used to determine candidate optimal sensor suites and initial results are provided.

Dwyer Cianciolo, Alicia↗

Robust Algorithm for Estimating Total Suspended Solids (TSS) in Inland and Nearshore Coastal Waters

One of the challenging tasks in modern aquatic remote sensing is the retrieval of near-surface concentrations of Total Suspended Solids (TSS). This study aims to present a Statistical, inherent Optical property (IOP) -based, and muLti-conditional Inversion proceDure (SOLID) for enhanced retrievals of satellite-derived TSS under a wide range of in-water bio-optical conditions in rivers, lakes, estuaries, and coastal waters. In this study, using a large in situ database (N > 3500), the SOLID model is devised using a three-step procedure: (a) water-type classification of the input remote sensing reflectance (R(sub rs)), (b) retrieval of particulate backscattering (b(sub bp)) in the red or near-infrared (NIR) regions using semi-analytical, machine-learning, and empirical models, and (c) estimation of TSS from b(sub bp) via water-type-specific empirical models. Using an independent subset of our in situ data (N = 2729) with TSS ranging from 0.1 to 2626.8 [g/m (exp 3)], the SOLID model is thoroughly examined and compared against several state-of-the-art algorithms (Miller and McKee, 2004; Nechad et al., 2010; Novoa et al., 2017; Ondrusek et al., 2012; Petus et al., 2010). We show that SOLID outperforms all the other models to varying degrees, i.e., from 10 to > 100%, depending on the statistical attributes (e.g., global versus water-type-specific metrics). For demonstration purposes, the model is implemented for images acquired by the MultiSpectral Imager aboard Sentinel-2A/B over the Chesapeake Bay, San-Francisco-Bay-Delta Estuary, Lake Okeechobee, and Lake Taihu. To enable generating consistent, multimission TSS products, its performance is further extended to, and evaluated for, other missions, such as the Ocean and Land Color Instrument (OLCI), Moderate Resolution Imaging Spectroradiometer (MODIS), Visible Infrared Imaging Radiometer Suite (VIIRS), and Operational Land Imager (OLI). Sensitivity analyses on uncertainties induced by the atmospheric correction indicate that 10% uncertainty in Rrs leads to < 20% uncertainty in TSS retrievals from SOLID. While this study suggests that SOLID has a potential for producing TSS products in global coastal and inland waters, our statistical analysis certainly verifies that there is still a need for improving retrievals across a wide spectrum of particle loads.

Total suspended solids↗

Simplifying Operations with an Uplink/Downlink Integration Toolkit

The Operations Engineering Lab (OEL) at JPL has developed a simple, generic toolkit to integrate the uplink/downlink processes (often called closing the loop) in JPL's Multimission Ground Data System. This toolkit provides capabilities for integrating telemetry verification points with predicted spacecraft commands and ground events in the Mission Sequence of Events (SOE) document. This toolkit is designed to greatly simplify the user's ability to access and view telemetry data, and also provide a means to view this data in a context of the commands and ground events that are used to interpret it. This paper will discuss the toolkit implementation, including design trade-offs and future for enhancing the automated capabilities.

ground↗

Using Task Analysis to Understand the Data System Operations Team

The Data System Operations Team (DSOT) currently monitors and controls the Multimission Ground Data System (MGDS) at NASA's Jet Propulsion Laboratory. The MGDS currently supports five spacecraft and within the next five years it will support ten spacecraft simultaneously. The ground processing element of the MGDS consists of a distributed UNIX-based system of over 40 nodes and 100 processes. The MGDS system provides operators with little or no information about the system's end-to-end processing status or end-to-end configuration. The lack of system visibility has become a critical issue in the daily operation of the MGDS. A task analysis was conducted to determine what kinds of tools were needed to provide DSOT with useful status information and to prioritize the tool development...

Holder, Barbara E.↗

Using Task Analysis to Understand the Data System Operations Team

The Data System Operations Team (DSOT) currently monitors the Multimission Ground Data System (MGDS) at NASAճ Jet Propulsion Laboratory. The MGDS currently supports five spacecraft and within the next five years it will support ten spacecraft simultaneously. The ground processing element of the MGDS consists of a distributed UNIX-based system of over 40 nodes and 100 processes. The MGDS system provides operators with little or no information about the system's end-to-end processing status or end-to-end configuration. The lack of system visibility has become a critical issue in the daily operation of the MGDS. A task analysis was conducted to determine what kinds of tools were needed to provide DSOT with useful status information and to prioritize the tool development. The analysis provided the formality and structure needed to get the right information exchange between development and operations.

Holder, B. E.↗

Orbit Determination of Hiten for Insertion into Lunar Orbit

This paper describes the JPL discovery of an integrated trajectory, and the tracking and orbit determination suuport provided by JPL's Deep Space Network and Multimission Navigation Team in support of the final targeting for lunar insertion.

Hiten↗

Using the SPICE System to Help Plan and Interpret Space Science Observations

A portable multimission information system named SPICE is used to assemble, archive, and provide easy access to viewing and other ancillary information needed by space scientists to interpret observations of bodies within our solar system. The modular nature of this system lends it to use in planning such observations as well. Since a successful proof of concept on Voyager, the SPICE system has been adapted to several recent JPL spacecraft missions and a variety of ground based operations. Other adaptations are underway. SPICE has been used to support observation planning for moving targets on the Hubble Space Telescope Project. Applications for SPICE on earth science, space physics, and other astrophysics missions are under consideration.

data↗

Automated Spacecraft Conjunction Assessment at Mars and the Moon - A Five Year Update

It is well known that the Earth has an ongoing problem with orbiting space debris. Some Earth orbiting missions have regular warnings of close approaches with debris or other satellites. At Mars and the Moon, due to the growing number of orbiter missions and the current inability to track orbital debris in these environments, the creation of a hazardous debris field must be avoided because a debris field would greatly complicate both existing and future operations. Work at the Jet Propulsion Laboratory in the area of automated spacecraft conjunction assessment at Mars and the Moon has been conducted over the past six years using a process called "MADCAP" ("Multimission Automated Deepspace Conjunction Assessment Process"). A paper introducing this work was presented at Space Ops in Stockholm, Sweden in 2012. In that inaugural paper, the then current state of operations was presented along with a number of items that were identified for potential future work. The fundamental design concepts of MADCAP have not materially changed in the last five years, however, since 2012 a number of the changes to MADCAP identified in the previous paper have been implemented. Some other previously planned work has not progressed appreciably; several of these items remain on a "parking lot" list. In addition to the items that were listed as prospective future work, JPL's Mars/Moon conjunction assessment efforts have also been extended in a few unplanned but important areas. This follow-up paper will provide a five year update on MADCAP operations at Mars and the Moon.

Wilson, Roby S.↗

Next Generation Relay Services at Mars via an International Relay Network

Nearly all data acquired by vehicles on the surface of Mars are returned to Earth via Mars orbiters – more than 1.7 terabits so far. Successful communication between the various spacecraft is achieved via the careful implementation of internationally recognized CCSDS telecommunications protocols and the use of planning and coordination services provided by NASA’s Mars Program Office and the Multimission Ground Systems and Services (MGSS) Program at the Jet Propulsion Laboratory in Pasadena, CA. This modern Mars relay network has evolved since its inception in 2004 with the addition and loss of several missions, but it has fundamentally remained unchanged. Ground interfaces between the various spacecrafts’ mission operations centers on Earth remain largely unique for each participant, each mission maintains its own interfaces with deep space communications networks (e.g. DSN, ESTRACK), which are similar but still unique; and relay sessions at Mars require careful ground planning, coordination, and implementation. This paper will discuss the existing architecture and consider how several technologies may be applied to the next generation of relay services at Mars. Ultimately, these are expected to lead to the implementation of a delay and disruption tolerant network at Mars, a precursor to becoming a major element in an emerging Solar System Internet.

Edwards, Charles D. Jr↗

Blackbird: Object-Oriented Planning, Simulation, and Sequencing Framework Used by Multiple Missions

Every JPL flight mission relies on activity planning and sequence generation software to perform operations. Most such tools in use at JPL and elsewhere use attribute-based schemas or domain-specific languages (DSLs) to define activities. This reliance poses user training, software maintenance, performance, and other challenges. To solve this problem for future missions, a new software called Blackbird was developed which allows engineers to specify behavior in standard Java. The new code base has over an order of magnitude fewer lines of code than other JPL planning software, since no DSL or schema interpreter is needed. The use of Java for defining activities also allows mission adapters to debug their code in an integrated development environment, seamlessly call external libraries, and set up truly multimission models. These efficiency gains have significantly reduced the amount of development effort required to support the software. This paper discusses Blackbird’s design, principles, and use cases.

Lawler, Christopher↗

Detection of Rossby Waves in Multi-Parameters in Multi-Mission Satellite Observations and HYCOM Simulations in the Indian Ocean

Rossby waves are difficult to detect with in situ methods. However, as we show in this paper, they can be clearly identified in multi-parameters in multi-mission satellite observations of sea surface height (SSH), sea surface temperature (SST) and ocean color observations of chlorophyll-a (chl-a), as well as 1/12-deg global HYbrid Coordinate Ocean Model (HYCOM) simulations of SSH, SST and sea surface salinity (SSS) in the Indian Ocean. While the surface structure of Rossby waves can be elucidated from comparisons of the signal in different sea surface parameters, models are needed to gain direct information about how these waves affect the ocean at depth. The first three baroclinic modes of the Rossby waves are inferred from the Fast Fourier Transform (FFT), and two-dimensional Radon Transform (2D RT). At many latitudes the first and second baroclinic mode Rossby wave phase speeds from satellite observations and model parameters are identified.

SSH (SEA SURFACE HEIGHT)↗