Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “data protection”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

Securing Ground Data System Applications for Space Operations

The increasing prevalence and sophistication of cyber attacks has prompted the Multimission Ground Systems and Services (MGSS) Program Office at Jet Propulsion Laboratory (JPL) to initiate the Common Access Manager (CAM) effort to protect software applications used in Ground Data Systems (GDSs) at JPL and other NASA Centers. The CAM software provides centralized services and software components used by GDS subsystems to meet access control requirements and ensure data integrity, confidentiality, and availability. In this paper we describe the CAM software; examples of its integration with spacecraft commanding software applications and an information management service; and measurements of its performance and reliability.

Security↗
NASA NTRS1983

An assessment of the Space Shuttle Orbiter thermal environment using flight data

A unified analysis of the Shuttle Orbiter aerothermodynamic environment and thermal protection system performance is presented using the Space Transportation System development flight data. Comparisons of predicted and measured temperatures and heating rates along the Orbiter lower windward fuselage centerline and lower wing 50 percent and 80 percent semi-spans are discussed. The results of this study indicate lower than predicted heating on windward fuselage surface but higher heating on the nose cap and 50 percent semi-span wing panels.

Williams, S. D.↗
NASA NTRS1969

IBM-1620 monitor 2-D disk-storage subroutines

Set of subroutines provides the FORTRAN user with protected, permanent, disk storage of data on an IBM 1620 Monitor 11-D system. The program consists of a set of four subroutines and a utility program. It allows block data to be transferred directly between assigned core locations and disk storage.

Krejci, H. F.↗
NASA NTRS1979

Capability for aerothermal-structural tests of large-to-full-scale components of future space transportation systems

The design of viable, low-mass thermostructural concepts for future space transportation systems requires accurate definition of the localized heat flux, pressures, and flow-surface interaction parameters for complex flow regions of detailed areas of large vehicles, such as wing-elevon coves, thermal protection system tile gaps, and corrugated metallic surfaces. This paper discusses investigations recently conducted in and planned for two high-energy wind tunnels at the Langley Research Center - the 8-foot High-temperatures Tunnel and the Thermal Protection System Test Facility. The data obtained on large-to-full-scale vehicle components, comparisons of the experimental data with theory, and the large, reusable, generalized test apparatus available at or planned for these facilities are discussed.

Couch, L. M.↗
NASA NTRS1999

Results from the First Two Flights of the Static Computer Memory Integrity Testing Experiment

This paper details the scientific objectives, experiment design, data collection method, and post flight analysis following the first two flights of the Static Computer Memory Integrity Testing (SCMIT) experiment. SCMIT is designed to detect soft-event upsets in passive magnetic memory. A soft-event upset is a change in the logic state of active or passive forms of magnetic memory, commonly referred to as a "Bitflip". In its mildest form a soft-event upset can cause software exceptions, unexpected events, start spacecraft safeing (ending data collection) or corrupted fault protection and error recovery capabilities. In it's most severe form loss of mission or spacecraft can occur. Analysis after the first flight (in 1991 during STS-40) identified possible soft-event upsets to 25% of the experiment detectors. Post flight analysis after the second flight (in 1997 on STS-87) failed to find any evidence of soft-event upsets. The SCMIT experiment is currently scheduled for a third flight in December 1999 on STS-101.

Hancock, Thomas M., III↗
NASA NTRS2002

Monitoring the Ancient Countryside: Remote Sensing and GIS at the Chora of Chersonesos (Crimea, Ukraine)

In 1998 the University of Texas Institute of Classical Archaeology, in collaboration with the University of Texas Center for Space Research and the National Preserve of Tauric Chersonesos (Ukraine), began a collaborative project, funded by NASA's Solid Earth and Natural Hazards program, to investigate the use of remotely sensed data for the study and protection of the ancient a cultural territory, or chora, of Chersonesos in Crimea, Ukraine.

Trelogan, Jessica↗
NASA NTRS2005

Assessing the Relative Risk of Aerocapture Using Probabalistic Risk Assessment

A recent study performed for the Aerocapture Technology Area in the In-Space Propulsion Technology Projects Office at the Marshall Space Flight Center investigated the relative risk of various capture techniques for Mars missions. Aerocapture has been proposed as a possible capture technique for future Mars missions but has been perceived by many in the community as a higher risk option as compared to aerobraking and propulsive capture. By performing a probabilistic risk assessment on aerocapture, aerobraking and propulsive capture, a comparison was made to uncover the projected relative risks of these three maneuvers. For mission planners, this knowledge will allow them to decide if the mass savings provided by aerocapture warrant any incremental risk exposure. The study focuses on a Mars Sample Return mission currently under investigation at the Jet Propulsion Laboratory (JPL). In each case (propulsive, aerobraking and aerocapture), the Earth return vehicle is inserted into Martian orbit by one of the three techniques being investigated. A baseline spacecraft was established through initial sizing exercises performed by JPL's Team X. While Team X design results provided the baseline and common thread between the spacecraft, in each case the Team X results were supplemented by historical data as needed. Propulsion, thermal protection, guidance, navigation and control, software, solar arrays, navigation and targeting and atmospheric prediction were investigated. A qualitative assessment of human reliability was also included. Results show that different risk drivers contribute significantly to each capture technique. For aerocapture, the significant drivers include propulsion system failures and atmospheric prediction errors. Software and guidance hardware contribute the most to aerobraking risk. Propulsive capture risk is mainly driven by anomalous solar array degradation and propulsion system failures. While each subsystem contributes differently to the risk of each technique, results show that there exists little relative difference in the reliability of these capture techniques although uncertainty for the aerocapture estimates remains high given the lack of in-space demonstration.

Percy, Thomas K.↗
NASA NTRS2011

Integration of In-Flight and Post-Flight Water Monitoring Resources in Addressing the U.S. Water Processor Assembly Total Organic Carbon (TOC) Anomaly

Beginning in June of 2010, the total organic carbon (TOC) concentration in the U.S. Water Processor Assembly (WPA) product water started to increase. A surprisingly consistent upward TOC trend was observed through weekly ISS total organic carbon analyzer (TOCA) monitoring. As TOC is a general organic compound indicator, return of water archive samples was needed to make better-informed crew health decisions on the specific compounds of concern and to aid in WPA troubleshooting. TOCA-measured TOC was more than halfway to the health-based screening limit of 3,000 g/L before archive samples were returned. Archive samples were returned on 22 Soyuz in September 2010 and on ULF5 in November of 2010. The samples were subjected to extensive analysis. Although TOC was confirmed to be elevated, somewhat surprisingly, none of the typical target compounds were detected at high levels. After some solid detective work, it was confirmed that the TOC was associated with a compound known as dimethylsilanediol (DMSD). DMSD is believed to be a breakdown product of siloxanes which are thought to be ubiquitous in the ISS atmosphere. A toxicological limit was set for DMSD and a forward plan was developed for conducting operations in the context of understanding the composition of the TOC measured in flight. This required careful consideration of existing ISS flight rules, coordination with ISS stakeholders, and development of a novel approach for the blending of inflight TOCA data with archive results to protect crew health. Among other challenges, team members had to determine how to utilize TOCA readings when making decisions about crew consumption of WPA water. This involved balancing very real concerns associated with the assumption that TOC would continue to be comprised of only DMSD. Demonstrated teamwork, multidisciplinary awareness, and innovative problem-solving were required to respond effectively to this anomaly.

Straub, John E., II↗
NASA NTRS2014

Detector Array Assembly Development for the ATLAS Instrument on the ICESat-2 Mission

This paper describes the development of the Detector Array Assembly (DAA) structure for the Advanced Topographic Laser Altimeter System (ATLAS) on the ICESat2 Mission built at NASA Goddard Space Flight Center (GSFC). It describes the challenges faced in designing a structure to protect sensitive detectors with limited data available for the detectors and the environment, including shock. The paper shows the successful re-design and testing that was performed to allow for a design to handle launch, shock and thermal environments with flexibility to incorporate design changes.

0000↗
NASA NTRS2018

Orion EM-2 TPS Radiometer & Spectrometer

Radiometers and Spectrometers embedded as flight instrumentation in a spacecraft's thermal protection system (TPS) can generate data on shock layer radiation to a spacecraft's surface for high-speed trajectories such as lunar return. Robust and accurate flight measurements of shock layer radiation can validate models and inform TPS selection and sizing, to reduce risk and TPS launch mass. Contamination from soot deposition and ablation products in the boundary layer condensing on a cold sapphire radiometer window or blocking open ports interferes with measurements. This poster describes characterization of the optical properties and performance of relevant materials, components, and contaminated windows, as well as investigation of contamination control strategies for the optics.

Ablation↗
NASA NTRS1995

Integrated Utility Module for Future NASA Miniature Spacecraft

NASA initiated a program for space-validation of selected technologies relating to miniature spacecraft and microinstruments. Addressed is the proposed development of the Integrated Utility Module (IUM) which integrates structural integrity, thermal management, power distribution, data & signal transmission, radiation & meteoroid protection, etc. into a lightweight, compact, cableless package.

NASA↗
NASA NTRSDate not supplied

A Microphone Phased Array for Launch Acoustics Application

A new, portable, phased array of microphones is built at NASA Ames Research Center specifically for the harsh environment encountered in launch acoustics applications. It uses 70 rugged, piezo-electric, dynamic pressure sensors optimally distributed on a 10.5ft diameter open frame dome structure. The open frame is light yet robust to sustain the high wind load of typical seaside launch pads, and the blast and acoustic loads from the launch. A 200-ft long cable bundle carries the microphone signals to a weather-protected electronic cabinet containing the data acquisition system, computers, and other equipment. The array is equipped with an infra-red camera and a visible wavelength camera for imaging the launch site. The beamformed noise maps will be superimposed on the video footages collected by the cameras for correct identification of the noise sources. The array is tested with very loud noise sources to determine the beamforming ability. Multiple mathematical models, such as the conventional beamforming, functional beamforming, spectral element method etc. are used to determine the minimum spatial resolution of the sound sources that can be measured at different frequencies. Additionally, the array hardware is being tested for different environmental conditions and electro-magnetic compliance. The immediate goal is to use the array for NASA’s Artemis/SLS vehicle that will be launched from a newly built Mobile Launch platform and a modified launch pad.

microphone phased-array↗
NASA NTRSDate not supplied

A Microphone Phased Array for Launch Acoustics Application

A new, portable, phased array of microphones is built at NASA Ames Research Center specifically for the harsh environment encountered in launch pads of rocket vehicles. It uses 70 rugged, piezo-electric, dynamic pressure sensors optimally distributed on a 10.5ft diameter open frame dome structure. The open frame is light yet robust to sustain the high wind load of typical seaside launch pads, and the blast and acoustic loads from the launch. A 200-ft long cable bundle carries the microphone signals to a weather-protected electronic cabinet containing the data acquisition system, computers, and other equipment. The array is equipped with an infra-red camera and a visible wavelength camera for imaging the launch site. The beamformed noise maps will be superimposed on the video footages collected by the cameras for correct identification of the noise sources. The array is tested with very loud noise sources to determine the beamforming ability. Multiple mathematical models, such as the conventional beamforming, orthogonal-functional beamforming, spectral element method etc. are used to determine the minimum spatial resolution of the sound sources that can be measured at different frequencies. Additionally, the array hardware is being tested for different environmental conditions and electro-magnetic compliance. The goal is to use the array for NASA’s Artemis/SLS vehicle that will be launched from a newly built Mobile Launch platform and a modified launch pad. Data from a couple of validation tests will be presented in this paper. The first test involves an outdoor setup where the array was placed on a crane at several different heights and distances from a pair of very loud noise sources. The second test from the static firing of the RS25 engines in an outdoor test stand.

Acoustics↗
NASA NTRS2016

The Quality Control Algorithms Used in the Creation of NASA Kennedy Space Center Lightning Protection System Towers Meteorological Database

An accurate database of meteorological data is essential for designing any aerospace vehicle and for preparing launch commit criteria. Meteorological instrumentation were recently placed on the three Lightning Protection System (LPS) towers at Kennedy Space Center (KSC) launch complex 39B (LC-39B), which provide a unique meteorological dataset existing at the launch complex over an extensive altitude range. Data records of temperature, dew point, relative humidity, wind speed, and wind direction are produced at 40, 78, 116, and 139 m at each tower. The Marshall Space Flight Center Natural Environments Branch (EV44) received an archive that consists of one-minute averaged measurements for the period of record of January 2011 - April 2015. However, before the received database could be used EV44 needed to remove any erroneous data from within the database through a comprehensive quality control (QC) process. The QC process applied to the LPS towers' meteorological data is similar to other QC processes developed by EV44, which were used in the creation of meteorological databases for other towers at KSC. The QC process utilized in this study has been modified specifically for use with the LPS tower database. The QC process first includes a check of each individual sensor. This check includes removing any unrealistic data and checking the temporal consistency of each variable. Next, data from all three sensors at each height are checked against each other, checked against climatology, and checked for sensors that erroneously report a constant value. Then, a vertical consistency check of each variable at each tower is completed. Last, the upwind sensor at each level is selected to minimize the influence of the towers and other structures at LC-39B on the measurements. The selection process for the upwind sensor implemented a study of tower-induced turbulence. This paper describes in detail the QC process, QC results, and the attributes of the LPS towers meteorological database.

Orcutt, John M.↗
NASA NTRS2007

A Risk-Based Approach for Aerothermal/TPS Analysis and Testing

The current status of aerothermal and thermal protection system modeling for civilian entry missions is reviewed. For most such missions, the accuracy of our simulations is limited not by the tools and processes currently employed, but rather by reducible deficiencies in the underlying physical models. Improving the accuracy of and reducing the uncertainties in these models will enable a greater understanding of the system level impacts of a particular thermal protection system and of the system operation and risk over the operational life of the system. A strategic plan will be laid out by which key modeling deficiencies can be identified via mission-specific gap analysis. Once these gaps have been identified, the driving component uncertainties are determined via sensitivity analyses. A Monte-Carlo based methodology is presented for physics-based probabilistic uncertainty analysis of aerothermodynamics and thermal protection system material response modeling. These data are then used to advocate for and plan focused testing aimed at reducing key uncertainties. The results of these tests are used to validate or modify existing physical models. Concurrently, a testing methodology is outlined for thermal protection materials. The proposed approach is based on using the results of uncertainty/sensitivity analyses discussed above to tailor ground testing so as to best identify and quantify system performance and risk drivers. A key component of this testing is understanding the relationship between the test and flight environments. No existing ground test facility can simultaneously replicate all aspects of the flight environment, and therefore good models for traceability to flight are critical to ensure a low risk, high reliability thermal protection system design. Finally, the role of flight testing in the overall thermal protection system development strategy is discussed.

Wright, Michael J.↗
NASA NTRS2004

Historical Study of Radiation Exposures and the Incidence of Cataracts in Astronauts

For over 35 years, astronauts in low Earth orbit or on missions to the moon have been exposed to space radiation comprised of high-energy protons, heavy ions, and secondary neutrons. We reviewed the radiation exposures received by astronauts in space and on Earth, and presented results from the first epidemiological study of cataract incidence in the astronauts. Our data suggested an increased risk for cataracts from space radiation exposures. Using parametric survival analysis and the maximum likelihood method, we estimated the dose-response and age distribution for cataract incidence in astronauts by space radiation. Considering the high-LET dose contributions on specific space missions as well as data from animal studies with neutrons and heavy ions, suggested a linear response with no dose-threshold for cataracts. However, there are unanswered questions related to the importance and the definition of clinically significant cataracts commonly used in radiation protection, especially in light of epidemiological data suggesting that the probability that sub-clinical cataracts will progress is highly dependent on the age at which cataracts appear. We briefly describe a new study that will address the measurement of cataract progression-rates in astronauts and a ground-based comparison group.

Cucinotta, F. A.↗
NASA NTRS2004

Historical Study of Radiation Exposures and the Incidence of Cataracts in Astronauts

For over 35 years, astronauts in low Earth orbit or on missions to the moon have been exposed to space radiation comprised of high-energy protons, heavy ions, and secondary neutrons. We reviewed the radiation exposures received by astronauts in space and on Earth, and presented results from the first epidemiological study of cataract incidence in the astronauts. Our data suggested an increased risk for cataracts from space radiation exposures*. Using parametric survival analysis and the maximum likelihood method, we estimated the dose-response and age distribution for cataract incidence in astronauts by space radiation. Considering the high-LET dose contributions on specific space missions as well as data from animal studies with neutrons and heavy ions, suggested a linear response with no dose-threshold for cataracts. However, there are unanswered questions related to the importance and the definition of "clinically significant" cataracts commonly used in radiation protection, especially in light of epidemiological data suggesting that the probability that "sub-clinical" cataracts will progress is highly dependent on the age at which cataracts appear. We briefly describe a new study that will address the measurement of cataract progression-rates in astronauts and a ground-based comparison group.

Cucinotta, F. A.↗
NASA NTRS2023

Northeast Alaska Climate: Using Earth Observations to Evaluate Snow Variability through a Climatological Analysis to Support Ecological Monitoring in Northeast Alaska

Alaska is experiencing climate change at an unprecedented rate, with temperatures increasing twice as fast as the national average. The resulting changes to the landscape and ecosystems are significant, including shorter winters, declining snow depth, thawing permafrost, and rapidly receding glaciers. These changes are not only exacerbating the negative impacts of oil exploration but also affecting the food security of indigenous communities that rely on hunting as a subsistence food source. With the US Fish and Wildlife Service managing a potential tundra travel season for the first time in its history, adequate data on historic snow variables is essential to protect the unique habitat of the area. This project used NASA satellite and assimilation system data to inform and improve the current understanding of snow patterns in the Arctic National Wildlife Refuge and the National Petroleum Reserve – Alaska. The DEVELOP team used MODIS Normalized Difference Snow Index data to determine snow season duration, snow change frequency, and the first and last days of snow. The team also utilized the 2.1 Global Land Data Assimilation System and Daymet V4 products to study climatological trends in snow depth and snow water equivalent, respectively, across the study areas. The results of this study give users the capacity to visualize maps of multiple snow variables to monitor changes in snow conditions and proactively prepare for the ecological, cultural, and landscape impacts that changes in snow variability will cause in the future.

Remote Sensing↗