Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “space frame”

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 1,531 records · Page 85
All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

SCA Test Report: H4RG-21224 WFIRST

This report summarizes the measured performance for the Sensor Chip Assembly (SCA), which is identified in Table 1. The SCA architecture is a substrate-removed HgCdTe detector with an area of 4096x4096 pixels (with a reference pixel area of four pixels deep around all four sides, available to substitute corresponding image pixels) and a pixel pitch of 10 μm.This SCA has been tested at the Goddard Space Flight Center (GSFC/NASA) Detector Characterization Laboratory (DCL). Teledyne (the vendor) classifies its detectors into different grades based on testing performed at its facility. The classification of this SCA and the tested dates are included in Table 1 below.The tests performed on this array are derived from the document WFIRST-PROC-09220_WFIRST-SCA-ATP_-.docx. A summary of the test parameters, requirements, and test results is presented in Table 2. The details of each test are subsequently described in the report. In the Summary (Table 2), SCA results are reported at an operating temperature of 95K, and 1.0 V bias voltage. In the detailed section of each test, the results for 95 K and 0.5V bias voltage is also reported. The data for the result reported in this document was acquired in pixel reset mode. For all cases, the frame time used is 2.830 seconds. Reference pixel correction was applied to every raw frame.

Laddawan Miko↗
NASA NTRS2021

SCA Test Report H4RG-21645 Roman Space Telescope

This report summarizes the measured performance for the Sensor Chip Assembly (SCA), which is identified in Table 1. The SCA architecture is a substrate-removed HgCdTe detector with an area of 4096x4096 pixels (with a reference pixel area of four pixels deep around all four sides, available to substitute corresponding image pixels) and a pixel pitch of 10 μm. This SCA has been tested at the Goddard Space Flight Center (GSFC/NASA) Detector Characterization Laboratory (DCL). Teledyne (the vendor) classifies its detectors into different grades based on testing performed at its facility. The classification of this SCA and the tested dates are included in Table 1 below. The tests performed on this array are derived from the document WFIRST-PROC-09220_WFIRST-SCAATP_-.docx. A summary of the test parameters, requirements, and test results is presented in Table 2. The details of each test are subsequently described in the report. In the Summary (Table 2), SCA results are reported at an operating temperature of 95K, and 1.0 V bias voltage. In the detailed section of each test, the results for 95 K and 0.5V bias voltage is also reported. The data for the result reported in this document was acquired in pixel reset mode. For all cases, the frame time used is 2.830 seconds. Reference pixel correction was applied to every raw frame.

Laddawan Miko↗
NASA NTRS2021

SCA Test Report H4RG-21815: Roman Space Telescope

This report summarizes the measured performance for the Sensor Chip Assembly (SCA), which is identified in Table 1. The SCA architecture is a substrate-removed HgCdTe detector with an area of 4096x4096 pixels (with a reference pixel area of four pixels deep around all four sides, available to substitute corresponding image pixels) and a pixel pitch of 10 μm.This SCA has been tested at the Goddard Space Flight Center (GSFC/NASA) Detector Characterization Laboratory (DCL). Teledyne (the vendor) classifies its detectors into different grades based on testing performed at its facility. The classification of this SCA and the tested dates are included in Table 1 below. The tests performed on this array are derived from the document WFIRST-PROC-09220_WFIRST-SCA-ATP_-.docx.A summary of the test parameters, requirements, and test results is presented in Table 2. The details of each test are subsequently described in the report. In the Summary (Table 2), SCA results are reported at an operating temperature of 95K, and 1.0 V bias voltage. In the detailed section of each test, the results for 95 K and 0.5V bias voltage is also reported. The data for the result reported in this document was acquired in pixel reset mode. For all cases, the frame time used is 2.830 seconds. Reference pixel correction was applied to every raw frame.

Laddawan Miko↗
DOE OSTI2026

Energy shift of Fe-K fluorescence lines due to low ionization demonstrated with XRISM in Centaurus X-3

The Fe K$\alpha$ fluorescence line at 6.4 keV is a powerful probe of cold matter surrounding X-ray sources and has been widely used in various astrophysical contexts. The X-ray microcalorimeter spectrometer onboard XRISM can measure line shifts with unprecedented precision of ${\sim }$0.2 eV, equivalent to a line-of-sight velocity of ${\sim }$10 km s$^{-1}$. At this level of accuracy, however, several factors that influence the line energy must be carefully considered prior to astrophysical interpretation. One such important factor is the ionization degree, Fe$^{q+}$. The K$\alpha$ line shifts redward by ${\sim }$4 eV as q increases from 0 (neutral) to 8 (Ar-like). Additionally, the accompanying Fe K$\beta$ line at 7.06 keV shifts blueward by ${\sim }$30 eV from $q=0$ to 8. We demonstrate that this effect is actually observable in the XRISM data of the high-mass X-ray binary Centaurus X-3 (Cen X-3). We advocate that the differential energy shift between the K$\alpha$ and K$\beta$ line provides a robust estimate of q by decoupling from other effects that shift the two lines in the same direction. We derived $q \sim 5$ (Sc-like) for the fluorescing matter by comparing the observation with atomic structure calculations of our own and in the literature. By accounting for the derived charge state and the corresponding shift in the rest-frame line energy, we made corrections for this effect and reached a consistent residual shift among the K$\alpha$, K$\beta$, and the optical measurement attributable to the systemic velocity of the system. Consequently, we obtained a new constraint on the location of the cold matter. This ionization effect needs to be assessed in all use cases of the Fe K$\alpha$ line shift beyond Cen X-3, and the proposed metric is generally applicable to all of them.

Astronomy and AstroPhysics↗
NASA NTRS1989

Characterization testing of a 40 Ahr bipolar nickel hydrogen battery

In a continuing effort to develop NiH2 bipolar technology to a point where it can be used efficiently in space flight, testing of a second 40 Ahr, 10-cell bipolar battery has begun. This battery has undergone extensive characterization testing to determine the effects of such operating parameters as charge and discharge rates, temperature, and pressure. The fundamental design of this actively cooled bipolar battery is the same as the first battery. Most of the individual components, however, are from different manufacturers. Different testing procedures as well as certain unique battery characteristics make it difficult to directly compare the two sets of results. In general, the performance of this battery throughout characterization produced expected results. The main differences seen between the first and second batteries occurred during the high-rate discharge portion of the test matrix. The first battery also had poor high-rate discharge results, although better than those of the second battery. Minor changes were made to the battery frame design used for the first battery in an attempt to allow better gas access to the reaction sites for the second build and hopefully improve performance. The changes, however, did not improve the performance of the second battery and could have possibly contributed to the poorer performance that was observed. There are other component differences that could have contributed to the poorer performance of the second battery. The H2 electrode in the second battery was constructed with a Goretex backing which could have limited the high-rate current flow. The gas screen in the second battery had a larger mesh which again could have limited the high-rate current flow. Small scale 2 x 2 batteries are being tested to evaluate the effects of the component variations.

Brewer, Jeffrey C.↗
NASA NTRS2020

SCA Test Report: H4RG-21225 WFIRST

This report summarizes the measured performance for the Sensor Chip Assembly (SCA), which is identified in Table 1. The SCA architecture is a substrate-removed HgCdTe detector with an area of 4096x4096 pixels (with reference pixel area of four pixels deep around all four sides, available to substitute corresponding image pixels) and a pixel pitch of 10 μm. This SCA has been tested at the Goddard Space Flight Center (GSFC/NASA) Detector Characterization Laboratory (DCL). Teledyne (the vendor) classifies its detectors into different grades based on testing performed at its facility. The classification of this SCA and the tested dates are included in Table 1 below. The tests performed on this array are derived from the document WFIRST-PROC-09220_WFIRST-SCA-ATP_-.docx. A summary of the test parameters, requirements, and test results is presented in Table 2. The details of each test are subsequently described in the report. In the Summary (Table 2), SCA results are reported at an operating temperature of 95K, and 1.0 V bias voltage. In the detailed section of each test,the results for 95 K and 0.5V bias voltage is also reported. The data for the result reported in this document was acquired in pixel reset mode. For all cases, the frame time used is 2.830 seconds. Reference pixel correction was applied to every raw frame.

Laddawan Miko↗
NASA NTRS2020

SCA Test Report: H4RG-21317 WFIRST

This report summarizes the measured performance for the Sensor Chip Assembly (SCA), which is identified in Table 1. The SCA architecture is a substrate-removed HgCdTe detector with an area of 4096x4096 pixels (with a reference pixel area of four pixels deep around all four sides, available to substitute corresponding image pixels) and a pixel pitch of 10 μm.This SCA has been tested at the Goddard Space Flight Center (GSFC/NASA) Detector Characterization Laboratory (DCL). Teledyne (the vendor) classifies its detectors into different grades based on testing performed at its facility. The classification of this SCA and the tested dates are included in Table 1 below. The tests performed on this array are derived from the document WFIRST-PROC-09220_WFIRST-SCA-ATP_-.docx. A summary of the test parameters, requirements, and test results is presented in Table 2. The details of each test are subsequently described in the report. In the Summary (Table 2), SCA results are reported at an operating temperature of 95K, and 1.0 V bias voltage. In the detailed section of each test, the results for 95 K and 0.5V bias voltage is also reported. The data for the result reported in this document was acquired in pixel reset mode. For all cases, the frame time used is 2.830 seconds. Reference pixel correction was applied to every raw frame.

Laddawan Miko↗
NASA NTRS2020

SCA Test Report: H4RG-21319 WFIRST

This report summarizes the measured performance for the Sensor Chip Assembly (SCA), which is identified in Table 1. The SCA architecture is a substrate-removed HgCdTe detector with an area of 4096x4096 pixels (with a reference pixel area of four pixels deep around all four sides, available to substitute corresponding image pixels) and a pixel pitch of 10 µm. This SCA has been tested at the Goddard Space Flight Center (GSFC/NASA) Detector Characterization Laboratory (DCL). Teledyne (the vendor) classifies its detectors into different grades based on testing performed at its facility. The classification of this SCA and the tested dates are included in Table 1 below. The tests performed on this array are derived from the document WFIRST-PROC-09220_WFIRST-SCA-ATP_-.docx. A summary of the test parameters, requirements, and test results is presented in Table 2. The details of each test are subsequently described in the report. In the Summary (Table 2), SCA results are reported at an operating temperature of 95K, and 1.0 V bias voltage. In the detailed section of each test, the results for 95 K and 0.5V bias voltage is also reported. The data for the result reported in this document was acquired in pixel reset mode. For all cases, the frame time used is 2.830 seconds. Reference pixel correction was applied to every raw frame.

Laddawan Miko↗
NASA NTRS2021

SCA Test Report H4RG-21813: Roman Space Telescope

This report summarizes the measured performance for the Sensor Chip Assembly (SCA), which is identified in Table 1. The SCA architecture is a substrate-removed HgCdTe detector with an area of 4096x4096 pixels (with a reference pixel area of four pixels deep around all four sides, available to substitute corresponding image pixels) and a pixel pitch of 10 μm.This SCA has been tested at the Goddard Space Flight Center (GSFC/NASA) Detector Characterization Laboratory (DCL). Teledyne (the vendor) classifies its detectors into different grades based on testing performed at its facility. The classification of this SCA and the tested dates are included in Table 1 below. The tests performed on this array are derived from the document WFIRST-P ROC-09220_WFIRST-SCA-ATP_-.docx.A summary of the test parameters, requirements, and test results is presented in Table 2. The details of each test are subsequently described in the report. In the Summary ( Table 2), SCA results are reported at an operating temperature of 95K, and 1.0 V bias voltage. In the detailed section of each test, the results for 95 K and 0.5V bias voltage is also reported. The data for the result reported in this document was acquired in pixel reset mode. For all cases, the frame time used is 2.830 seconds. Reference pixel correction was applied to every raw frame.

Laddawan Miko↗
NASA NTRS2021

SCA Test Report H4RG-21814: Roman Space Telescope

This report summarizes the measured performance for the Sensor Chip Assembly (SCA), which is identified in Table 1. The SCA architecture is a substrate-removed HgCdTe detector with an area of 4096x4096 pixels (with a reference pixel area of four pixels deep around all four sides, available to substitute corresponding image pixels) and a pixel pitch of 10 μm.This SCA has been tested at the Goddard Space Flight Center (GSFC/NASA) Detector Characterization Laboratory (DCL). Teledyne (the vendor) classifies its detectors into different grades based on testing performed at its facility. The classification of this SCA and the tested dates are included in Table 1 below. The tests performed on this array are derived from the document WFIRST-P ROC-09220_WFIRST-SCA-ATP_-.docx.A summary of the test parameters, requirements, and test results is presented in Table 2. The details of each test are subsequently described in the report. In the Summary ( Table 2), SCA results are reported at an operating temperature of 95K, and 1.0 V bias voltage. In the detailed section of each test, the results for 95 K and 0.5V bias voltage is also reported. The data for the result reported in this document was acquired in pixel reset mode. For all cases, the frame time used is 2.830 seconds. Reference pixel correction was applied to every raw frame.

Laddawan Miko↗
DOE OSTI2023

Electrochemical mechanisms of leakage‐current in photovoltaic modules

Abstract This paper analyzes the mechanisms and pathways for leakage current flow observed in Si photovoltaic modules subjected to high temperature and humidity and a large voltage bias with respect to ground. The current inside of the frame is in the form of electron motion, but in the glass and polymer, it is in at least a large part attributable to the movement of ions. When the mode of current flow changes from electronic to ionic conduction, electrochemical reactions will take place at the interface. This can include reactions that produce volatile chemical species like H 2 , CO x , and O 2 , along with ionic species such as OH − and H 3 O + . Here, we see evidence of the importance of different charge carriers with different diffusion rates and the influence of electrochemical processes involved. The application of negative voltage to the cell circuit affects the resistivity of glass producing surfaces with poor conductivity but with some increases in the electrochemical potential producing complicated interactions that are important when the voltage is changed. In the polymer, there is the development of a space charge region and a chemical gradient providing two oppositional forces to current flow, which when released create a complicated discharge process. Here, we give a basic understanding of the charge/discharge of PV cells highlighting how the specific mechanisms are important in understanding some of the degradation processes in PV modules. We find that there is evidence of multiple significant charge carrier species with different diffusion time scales. The glass/polymer interface forms a depleted region of higher resistance after prolonged exposure to current. Charge also builds up at the polymer to cell antireflective coating interface and mostly flows to the gridlines to experience electrochemical reactions. These complexities result in non‐linear behavior where the apparent resistivities of the different layers change during charge/discharging processes, making the modeling of the current flow extremely difficult.

14 SOLAR ENERGY↗
NASA NTRS1990

Effects of spaceflight on rat pituitary cell function: Preflight and flight experiment for pituitary gland study on COSMOS, 1989

The secretory capacity of growth hormone (GH) and prolactin (PRL) cells prepared from rats flown in space on the 12.5 day mission of Cosmos 1887 and the 14 day mission of Cosmos 2044 was evaluated in several post-flight tests on Earth. The results showed statistically significant and repeatable decrements in hormone release, especially when biological assays (rather than immunological assays) were used in the tests. Significant and repeatable intracellular changes in GH cells from the flight animals were also found; most important were increases in the GH-specific cytoplasmic staining intensities and cytoplasmic areas occupied by hormore. Tail suspension of rats for 14 days, an established model for mimicking musculo-skeletal changes seen in spaceflown rats, results in some changes in GH and PRL cell function that were similar to those from spaceflown animals. Our results add to a growing body of data that described deconditioning of physiological systems in spaceflight and provide insights into the time frame that might be required for readaptation of the GH/PRL cell system upon return to Earth.

Hymer, Wesley C.↗
NASA NTRS1992

Effects of spaceflight on rat pituitary cell function

The secretory capacity of growth hormone (GH) and prolactin (PRL) cells prepared from rats flown in space on the 12.5 day mission of Cosmos 1887 and the 14 day mission of Cosmos 2044 was evaluated in several post-flight tests on earth. The results showed statistically significant and repeatable decrements in hormone release, especially when biological assays (rather than immunological assays) were used in the tests. Significant and repeatable intracellular changes in GH cells from the flight animals were also found; most important were increases in the GH-specific cytoplasmic staining intensities and cytoplasmic areas occupied by hormone. Tail suspension of rats for 14 days, an established model for mimicking musculo-skeletal changes seen in spaceflown rats, results in some changes in GH and PRL cell function that were similar to those from spaceflown animals. Our results add to a growing body of data that described deconditioning of physiological systems in spaceflight and provide insights into the time frame that might be required for readaptation of the GH/PRL cell system upon return to earth.

Hymer, W. C.↗
NASA NTRS1990

Space Station module Power Management And Distribution (PMAD) system

This project consists of several tasks which are unified toward experimentally demonstrating the operation of a highly autonomous, user-supportive power management and distribution system for Space Station Freedom (SSF) habitation/laboratory modules. This goal will be extended to a demonstration of autonomous, cooperative power system operation for the whole SSF power system through a joint effort with NASA's Lewis Research Center, using their Autonomous Power System. Short term goals for the space station module power management and distribution include having an operational breadboard reflecting current plans for SSF, improving performance of the system communications, and improving the organization and mutability of the artificial intelligence (AI) systems. In the middle term, intermediate levels of autonomy will be added, user interfaces will be modified, and enhanced modeling capabilities will be integrated in the system. Long term goals involve conversion of all software into Ada, vigorous verification and validation efforts and, finally, seeing an impact of this research on the operation of SSF. Conversion of the system to a DC Star configuration is now in progress, and should be completed by the end of October, 1989. This configuration reflects the latest SSF module architecture. Hardware is now being procured which will improve system communications significantly. The Knowledge-Based Management System (KBMS) is initially developed and the rules from FRAMES have been implemented in the KBMS. Rules in the other two AI systems are also being grouped modularly, making them more tractable, and easier to eventually move into the KBMS. Adding an intermediate level of autonomy will require development of a planning utility, which will also be built using the KBMS. These changes will require having the user interface for the whole system available from one interface. An Enhanced Model will be developed, which will allow exercise of the system through the interface without requiring all of the power hardware to be operational. The functionality of the AI systems will continue to be advanced, including incipient failure detection. Ada conversion will begin with the lowest level processor (LLP) code. Then selected pieces of the higher level functionality will be recorded in Ada and, where possible, moved to the LLP level. Validation and verification will be done on the Ada code, and will complete sometimes after completion of the Ada conversion.

Walls, Bryan↗
NASA NTRS2012

Summary of 2011 Direct and Nearby Lightning Strikes to Launch Complex 39B, Kennedy Space Center, Florida

A Lightning Protection System (LPS) was designed and built at Launch Complex 39B (LC39B), at the Kennedy Space Center (KSC), Florida in 2009. This LPS was instrumented with comprehensive meteorological and lightning data acquisition systems that were deployed from late 2010 until mid 2011. The first direct strikes to the LPS were recorded in March of 2011, when a limited number of sensors had been activated. The lightning instrumentation system detected a total of 70 nearby strokes and 19 direct strokes to the LPS, 2 of the 19 direct strokes to the LPS had two simultaneous ground attachment points (in both instances one channel terminated on the LPS and the other on the nearby ground). Additionally, there are more unaccounted nearby strokes seen on video records for which limited data was acquired either due to the distance of the stroke or the settings of the data acquisition system. Instrumentation deployment chronological milestones, a summary of lightning strikes (direct and nearby), high speed video frames, downconductor currents, and dH/dt and dE/dt typical waveforms for direct and nearby strokes are presented.

Mata, C.T.↗
NASA NTRS2013

Development of a Universal Waste Management System

A concept for a Universal Waste Management System (UWMS) has been developed based on the knowledge gained from over 50 years of space travel. It is being designed for Commercial Orbital Transportation Services (COTS) and Multi ]Purpose Crew Vehicle (MPCV) and is based upon the Extended Duration Orbiter (EDO) commode. The UMWS was modified to enhance crew interface and reduce volume and cost. The UWMS will stow waste in fecal canisters, similar to the EDO, and urine will be stowed in bags for in orbit change out. This allows the pretreated urine to be subsequently processed and recovered as drinking water. The new design combines two fans and a rotary phase separator on a common shaft to allow operation by a single motor. This change enhances packaging by reducing the volume associated with an extra motor, associated controller, harness, and supporting structure. The separator pumps urine to either a dual bag design for COTS vehicles or directly into a water reclamation system. The commode is supported by a concentric frame, enhancing its structural integrity while further reducing the volume from the previous design. The UWMS flight concept development effort is underway and an early output of the development will be a ground based UMWS prototype for manned testing. Referred to as the Gen 3 unit, this prototype will emulate the crew interface included in the UWMS and will offer a great deal of knowledge regarding the usability of the new design, allowing the design team the opportunity to modify the UWMS flight concept based on the manned testing.

Baccus, Shelley↗
NASA NTRS2012

Replacing the CCSDS Telecommand Protocol with the Next Generation Uplink (NGU)

The current CCSDS Telecommand (TC) Recommendations 1-3 have essentially been in use since the early 1960s. The purpose of this paper is to propose a successor protocol to TC. The current CCSDS recommendations can only accommodate telecommand rates up to approximately 1 mbit/s. However today's spacecraft are storehouses for software including software for Field Programmable Gate Arrays (FPGA) which are rapidly replacing unique hardware systems. Changes to flight software occasionally require uplinks to deliver very large volumes of data. In the opposite direction, high rate downlink missions that use acknowledged CCSDS File Delivery Protocol (CFDP)4 will increase the uplink data rate requirements. It is calculated that a 5 mbits/s downlink could saturate a 4 kbits/s uplink with CFDP downlink responses: negative acknowledgements (NAKs), FINISHs, End-of-File (EOF), Acknowledgements (ACKs). Moreover, it is anticipated that uplink rates of 10 to 20 mbits/s will be required to support manned missions. The current TC recommendations cannot meet these new demands. Specifically, they are very tightly coupled to the Bose-Chaudhuri-Hocquenghem (BCH) code in Ref. 2. This protocol requires that an uncorrectable BCH codeword delimit the TC frame and terminate the randomization process. This method greatly limits telecom performance since only the BCH code can support the protocol. More modern techniques such as the CCSDS Low Density Parity Check (LDPC)5 codes can provide a minimum performance gain of up to 6 times higher command data rates as long as sufficient power is available in the data. This paper will describe the proposed protocol format, trade-offs, and advantages offered, along with a discussion of how reliable communications takes place at higher nominal rates.

Consultative Committee for Space Data Systems (CCS↗
NASA NTRS1993

The Clementine instrument complement

The recent successes of the Galileo solid-state imaging (SSI) experiment at the Moon and Gaspra show the utility of multispectral imaging of planetary objects. 'Clementine' is the planetary community's 'code name' for the SDIO (Space Defense Initiative Organization), mission to the Moon and the asteroid Geographos. This mission is designed as a long term stressing test on sensors and space systems developed for SDIO. In the course of this test Clementine will obtain science data using a varied and powerful array of remote sensing instruments which were developed by or for Lawrence Livermore National Laboratory in Livermore, California. Clementine carries five cameras, one for navigation and four for science experiments. In addition, a laser ranger is included which will serve as a laser altimeter. The Clementine cameras cover a wider range of spatial resolutions and wavelength range than did Galileo and are almost ideally suited to mapping of mafic rock types as are present on the Moon and expected at Geographos. Calibration of the cameras will occur at the sensor calibration laboratory at LLNL. In flight calibrations, using standard stars and other standards should improve the stated accuracies. Signal-to-noise ratios (SNRs) include the following noise sources: shot noise, calibration error, digitization noise, readout noise, and frame transfer noise (where applicable). The achieved SNRs are a balance between detector saturation and acceptable image smear. The 'worst' case uses the longest possible integration times.

Lucey, Paul G.↗