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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

A Machine Learning Model for Solar Sail Shape Reconstruction Using Flight Data

Solar sail deformation leads to disturbance torques from solar radiation pressure, driving performance requirements for momentum management systems. For the Solar Cruiser technology demonstrator mission, we have developed a model leveraging neural network-based machine learning to derive sail shape characteristics. The model uses torque and attitude telemetry simulated from a reduced-order tensor model of the deformed sail mesh over a characterization sequence. The machine learning model predicts sail boom deflection with comparable accuracy to that of an onboard context camera. This model can discover sail shape with no additional mass or data downlink requirements, allowing for validation of sail force modeling assumptions using in flight data. The results from the project hold promise for the further implementation of machine learning techniques in solar sail telemetry analysis and control.

solar sail↗
NASA NTRSDate not supplied

A Machine Learning Model for Solar Sail Shape Reconstruction Using Flight Data

Solar sail deformation leads to disturbance torques from solar radiation pressure, driving performance requirements for momentum management systems. For the Solar Cruiser technology demonstrator mission, we have developed a model leveraging neural network-based machine learning to derive sail shape characteristics. The model uses torque and attitude telemetry simulated from a reduced-order tensor model of the deformed sail mesh over a characterization sequence. The machine learning model predicts sail boom deflection with comparable accuracy to that of an onboard context camera. This model can discover sail shape with no additional mass or data downlink requirements, allowing for validation of sail force modeling assumptions using in flight data. The results from the project hold promise for the further implementation of machine learning techniques in solar sail telemetry analysis and control.

solar sail↗
NASA NTRS2003

Chemical Data Assimilation: A Case Study of Solar Occultation Data From the Atlas 1 Mission of the Atmospheric Trace Molecule Spectroscopy Experiment

A key advantage of using data assimilation is the propagation of information from data-rich regions to data-poor regions, which is particularly relevant to the use of solar occultation data such as from ATMOS. For the first time an in depth uncertainty analyses is included in a photochemical model-data intercomparison including observation, representativeness, and theoretical uncertainty. Chemical data assimilation of solar occultation measurements can be used to reconstruct full diurnal cycles and to evaluate their chemical self-consistency. This paper considers as an example the measurements made by the Atmospheric Trace Molecule Spectroscopy Experiment (ATMOS) instrument Atlas-1 during March 1992 for a vertical profile flow tracking coordinates at an equivalent PV latitude of 38 S. ATMOS was chosen because it simultaneously observes several species. This equivalent PV latitude was chosen as it was where ATMOS n observed the atmosphere's composition over the largest range of altitudes. A single vertical profile was used so that the detailed diurnal information that assimilation utilizes could be highlighted. There is generally good self-consistency between the ATMOS Atlas-1 observations and photochemical theory.

Lary, D. J.↗
NASA NTRS2002

Comparison of Total Solar Irradiance with NASA/NSO Spectromagnetograph Data in Solar Cycles 22 and 23

An earlier study compared NASA/NSO Spectromagnetograph (SPM) data with spacecraft measurements of total solar irradiance (TSI) variations over a 1.5 year period in the declining phase of solar cycle 22. This paper extends the analysis to an eight-year period which also spans the rising and early maximum phases of cycle 23. The conclusions of the earlier work appear to be robust: three factors (sunspots, strong unipolar regions, and strong mixed polarity regions) describe most of the variation in the SPM record, but only the first two are associated with TSI. Additionally, the residuals of a linear multiple regression of TSI against SPM observations over the entire eight-year period show an unexplained, increasing, linear time variation with a rate of about 0.05 W m(exp -2) per year. Separate regressions for the periods before and after 1996 January 01 show no unexplained trends but differ substantially in regression parameters. This behavior may reflect a solar source of TSI variations beyond sunspots and faculae but more plausibly results from uncompensated non-solar effects in one or both of the TSI and SPM data sets.

Jones, Harrison P.↗
NASA NTRS1978

Collection, processing and dissemination of data for the national solar demonstration program

A national solar data system developed for the DOE by IBM provides for automatic gathering, conversion, transfer, and analysis of demonstration site data. NASA requirements for this system include providing solar site hardware, engineering, data collection, and analysis. The specific tasks include: (1) solar energy system design/integration; (2) developing a site data acquisition subsystem; (3) developing a central data processing system; (4) operating the test facility at Marshall Space Flight Center; (5) collecting and analyzing data. The systematic analysis and evaluation of the data from the National Solar Data System is reflected in a monthly performance report and a solar energy system performance evaluation report.

Day, R. E.↗
NASA NTRSDate not supplied

Solar Particle Event Modeling Compared To Satellite Data

Solar protons are the primary source of ionizing radiation for certain missions. Several models of these solar energetic proton events exist, giving different results. We compare three models with satellite data to assess these differences.

Alexander Henderson↗
NASA NTRS2023

Neural-Based Compression Scheme for Solar Image Data

Studying the solar system and especially the Sun relies on the data gathered daily from space missions. These missions are data-intensive and compressing this data to make them efficiently transferable to the ground station is a twofold decision to make. Stronger compression methods, by distorting the data, can increase data throughput at the cost of accuracy which could affect scientific analysis of the data. On the other hand, preserving subtle details in the compressed data requires a high amount of data to be transferred, reducing the desired gains from compression. In this work, we propose a neural network-based lossy compression method to be used in NASA’s data-intensive imagery missions. We chose NASA’s Solar Dynamics Observatory (SDO) mission which transmits 1.4 terabytes of data each day as a proof of concept for the proposed algorithm. In this work, we propose an adversarially trained neural network, equipped with local and non-local attention modules to capture both the local and global structure of the image resulting in a better trade-off in rate-distortion (RD) compared to conventional hand-engineered codecs. The RD variational autoencoder used in this work is jointly trained with a channel-dependent entropy model as a shared prior between the analysis and synthesis transforms to make the entropy coding of the latent code more effective. We also studied how optimizing perceptual losses could help our neural compressor to preserve high-frequency details of the data in the reconstructed compressed image. Our neural image compression algorithm outperforms currently-in-use and state-of-the-art codecs such as JPEG and JPEG-2000 in terms of the RD performance when compressing extreme-ultraviolet (EUV) data. As a proof of concept for use of this algorithm in SDO data analysis, we have performed coronal hole (CH) detection using our compressed images, and generated consistent segmentations, even at a compression rate of ∼ 0.1 bits per pixel (compared to 8 bits per pixel on the original data) using EUV data from SDO.

Image coding↗
NASA NTRS1994

Summary of solar cell data from the Long Duration Exposure Facility (LDEF)

The contractor has obtained and reviewed data relating solar cells assemblies (SCA's) flown as part of the following LDEF experiments: the Advanced Photovoltaic Experiment (S0014); the Solar Array Materials Passive LDEF Experiment (A0171); the Advanced Solar Cell and Coverglass Analysis Experiment (M0003-4); the LDEF Heat Pipe Experiment (S1001); the Evaluation of Thermal Control Coatings Y Solar Cells Experiment (S1002); and the Space Plasma-High Voltage Drainage Experiment (A0054). Where possible, electrical data have been tabulated and correlated with various environmental effects, including meteoroid and debris impacts, radiation exposure, atomic oxygen exposure, contamination, UV radiation exposure, and thermal cycling. The type, configuration, and location of all SCA's are documented here. By gathering all data and results together, a comparison of the survivability of the various types and configurations can be made.

Hill, David C.↗
NASA NTRS1990

Long duration exposure facility solar illumination data package

A post flight solar illumination data package was created by the LDEF thermal analysis data group in support of the LDEF science office data group. The data presented was prepared with the Thermal Radiation Analysis System (TRASYS) program. Ground tracking data was used to calculate daily orbital beta angles for the calculation of resultant fluxes. This data package will be useful in calculation of solar illumination fluent for a variety of beta angle orbital conditions encountered during the LDEF mission.

Berrios, William M.↗
NASA NTRS1986

Solar-Geophysical Data Number 498, February 1986. Part 2: (Comprehensive reports). Data for August1985, and miscellanea

Solar-Geophysical Data Number 498, February 1986, Part 2 (Comprehensive Reports), Data for August 1985, and Miscellenea contains the following: detailed index for 1985-86; data for August 1985--(Solar flares, Solar radio bursts at fixed frequencies, Solar X-ray radiation from GOES satellite, Mass ejections from the Sun, Active prominences and filaments); miscellaneous data--Meudon carte synoptique 13 May - 7 July 1985.

Coffey, H. E.↗
NASA NTRS1986

Solar-Geophysical Data Number 497, January 1986. Part 2: (Comprehensive reports). Data for July 1985, and miscellanea

Solar-Geophysical Data Number 497, January 1986. Part 2: (Comprehensive Reports); Data for July 1985, and Miscellanea contains the following: a detailed index for 1985; data for July 1985-(solar flares, solar radio bursts at fixed frequencies, solar x-ray radiation from GOES satellite, mass ejections from the sun, active prominences and filaments); and miscellaneous data-(Meudon carte synoptique 16 April - 13 May 1985, number of solar flares August 1966 - July 1985).

Coffey, H. E.↗
NASA NTRS1984

Solar-geophysical data number 479, August 1981. Part 2: (Comprehensive reports), data for January 1984 and August 1981 and miscellanea. Explanation of data reports issued as number 474 (supplement) February 1984

Various solar physical data are presented including: data for January 1984--(solar radio bursts af fixed frequencies, solar X-ray radiation from GOES satellite, Mass ejections from the sun); data for August 1981--solar flares; Miscellaneous data--(meudon carte synoptique, solar X-ray radiation from GOES satellite).

Coffey, H. E.↗
NASA NTRS1970

Coronagraphic solar limb data, 7 March 1970

Solar limb photographic, isodensity and isophotal data for eclipse of 7 March 1970 from coronagraph observations, noting coronal green line and prominence activity

Cain, S. D.↗
NASA NTRS1986

Solar-geophysical data number 499, March 1986. Part 2: (Comprehensive reports). Data for September 1986 and miscellanea

Solar-Geophysical Data Number 499, March 1986, Part 2 (Comprehensive Reports); Data for September 1985, and Miscellanea, contains the following: Detailed index for 1985 to 1986; Data for September 1985--(Solar flares, Solar radio bursts at fixed frequencies; Solar X-ray radiation from GOES satellite; Mass ejections from the Sun; Active prominences and filaments); (Meudon carte synoptique 7 July - 26 September 1985, Solar irradiance).

Coffey, H. E.↗
NASA NTRS1980

Solar terrestrial relationships related to thunderstorms and BUV dark current and ozone data

Solar terrestrial interactions as they affect Nimbus 4 BUV dark current and possibly affect thunderstorm occurrence are investigated. A solar wind index is calculated for 1970 to 1971. Dark current enhancements appear to be associated in some way with solar proton events and the solar wind index, but additional investigations by GSFC are required before conclusions can be drawn. Superposed epoch analysis of an index of North American thunderstorm occurrence reveals a discernible increase in the index magnitude on days 1 and 2 following solar proton events. There appears to be little or no 27 day recurrence tendency in thunderstorm occurrence frequency and no association with vorticity area index on a day to day basis.

Herman, J. R.↗
NASA NTRS1986

Solar-geophysical data number 499, March 1986, supplement

This supplement contains the description and explanation of the data in the monthly publication Solar-Geophysical Data, compiled by the National Geophysical Data Center (NGDC) in Boulder, Colo., USA. Solar-Geophysical Data is intended to keep research workers informed on a timely schedule of the major events of solar activity and the associated interplanetary, ionospheric, radio propagation and other geophysical effects.

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