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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Evaluation of the Reliability of Passive Infrared (PIR) Occupancy Sensors for Residential Indoor Lighting

Solid-state lighting (SSL) technologies have penetrated the general illumination market in recent years, largely replacing conventional technologies such as incandescent and fluorescent lighting. Most of the initial excitement about light-emitting diode (LED) sources for SSL devices focused on their energy savings potential resulting from vast improvements in source efficiency and luminous efficacy compared with conventional illumination products. More recently, the focus has shifted toward other aspects of lighting application efficiency, namely intensity effectiveness and spectral efficiency, because of the ease of controlling both the light intensity of LEDs with drive voltage and the color properties of the LED-based illuminators. To capitalize on the energy savings of increased intensity effectiveness and spectral efficiency, a lighting control system (LCS) is often used. While the current penetration of LCSs is relatively modest, it is anticipated that lighting controls (i.e., connected lighting, controls and LED and conventional lighting) could have an installed penetration as higher as 46% by the year 2035, saving an additional 1.3 quads of energy. Despite the large energy savings that can be gained from using LCSs, standard test methods for evaluating sensors employed in LCSs and reliability data of the LCSs and their components are generally lacking. The National Electrical Manufacturers Association (NEMA) developed the only standard, NEMA WD 7-2011 (R2016), to test occupancy and motion sensor performance (herein referred to as “the NEMA protocol”). In a previous U.S. Department of Energy (DOE) effort, some concerns of the NEMA protocol were identified (e.g., strict height and weight limits on test subjects, large amounts of manual effort, sometimes inconsistent repeatability). During the current work, a consistent detection length test (DLT) and a Robotic Sensor Evaluation System (RoboSES) were developed to alleviate some of these concerns. RoboSES acts as a human surrogate by using thermal pads on a mannequin and a remote-controlled mobile base to test a sensor’s field of view (FOV). This report builds on the earlier DOE efforts to understand sensor technologies used in LCSs for general illumination. Specifically, this report describes the optimization of RoboSES, characterizes and establishes test methods to assess the reliability of multiple passive infrared (PIR) sensors, and reports the findings of robustness and reliability testing on two commercial PIR sensors intended for residential applications. The information presented in this report is gained from up to 4,000 hours (hrs) of accelerated stress tests (ASTs).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Internet of Things (IoT) Products and Applications: Lighting - Manufacturer and End-User Perspectives

It is forecast that the Internet of Things (IoT) market will experience significant growth in the coming years, with many expecting compound annual growth rates generally in the mid-20% (Forbes 2017). For lighting manufacturers, this is a tremendous opportunity to revolutionize their products to address the dwindling sales of lamps, once a major revenue stream, and bring new capabilities and services to their customers through luminaires and other lighting system components. For end-users, lighting products of the future may do more than simply provide light, with a cadre of connected sensors and controls that may help them do everything from exploring energy saving opportunities in other building systems to data-mining occupancy data to optimize use of space or increase sales. The focus of this study is to evaluate where the lighting market is today with respect to integrating IoT into its product offerings and end-user experiences with IoT, and in particular with IoT incorporated into lighting systems. The benefits, in terms of energy savings, of encouraging the adoption of connected lighting systems beyond the current solid state lighting (SSL) path to more aggressive DOE SSL Program Goals can result in an additional 33-percent of the LED energy savings, or 1.4 Quads, in 2035 (Navigant 2016).

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1983

Software Specification Language

SSL translator aids in developing and checking software systems. Goal of SSL is to provide form of verification and consistency checking early in design phase. Serves as formal document to communicate software architecure to detailed designers.

Buckles, B. P.↗
NASA NTRS1988

Cost effective alternative to low irradiance measurements

Martin Marietta's Space Simulation Laboratory (SSL) has a Thermal Environment Simulator (TES) with 56 individually controlled heater zones. The TES has a temperature range of approximately minus 129 C to plus 149 C. Because of the ability of TES to provide complex irradiance distributions, it is necessary to be able to measure a wide range of irradiance levels. SSL currently uses ambient temperature controlled radiometers with the capacity to measure sink irradiance levels of approximately 42.6 mw/sq cm, sink temperature equals 21 C and up. These radiometers could not be used to accurately measure the lower irradiance levels of the TES. Therefore, it was necessary to obtain a radiometer or develop techniques which could be used to measure lower irradiance levels.

Oleary, Scott T.↗
NASA NTRS1992

Design evolution of a telerobotic servicer through neutral buoyancy simulation

This paper briefly recounts the history of telerobotic vehicles in the Space Systems Laboratory. Based on this overview, the design of two vehicles are examined in depth, and directly compared. The Beam Assembly Teleoperator was the first true telerobot designed be the Space Systems Laboratory, and has been used extensively for six years. Ranger is the newest telerobot of the SSL, and is currently under development for operational testing in the summer of 1992. The primary focus of this paper is to compare and contrast the design details of these two telerobots, and to examine in some detail the evolution of design knowledge on some telerobots gained over the years of neutral buoyancy testing in the SSL.

Akin, David L.↗
NASA NTRS1993

Potential roles for EVA and telerobotics in a unified worksite

Although telerobotics and extravehicular activity (EVA) are often portrayed as competitive approaches to space operations, ongoing research in the Space Systems Laboratory (SSL) has demonstrated the utility of cooperative roles in an integrated EVA/telerobotic work site. Working in the neutral buoyancy simulation environment, tests were performed on interactive roles or EVA subjects and telerobots in structural assembly and satellite servicing tasks. In the most elaborate of these tests to date, EVA subjects were assisted by the SSL's Beam Assembly Teleoperator (BAT) in several servicing tasks planned for Hubble Space Telescope, using the high-fidelity crew training article in the NASA Marshall Neutral Buoyancy Simulator. These tests revealed several shortcomings in the design of BAT for satellite servicing and demonstrated the utility of a free-flying or RMS-mounted telerobot for providing EVA crew assistance. This paper documents the past tests, including the use of free-flying telerobots to effect the rescue of a simulated incapacitated EVA subject, and details planned future efforts in this area, including the testing of a new telerobotic system optimized for the satellite servicing role, the development of dedicated telerobotic devices designed specifically for assisting EVA crew, and conceptual approaches to advanced EVA/telerobotic operations such as the Astronaut Operations Vehicle.

Akin, David↗
NASA NTRS2014

Method of Performance-Aware Security of Unicast Communication in Hybrid Satellite Networks

A method and apparatus utilizes Layered IPSEC (LES) protocol as an alternative to IPSEC for network-layer security including a modification to the Internet Key Exchange protocol. For application-level security of web browsing with acceptable end-to-end delay, the Dual-mode SSL protocol (DSSL) is used instead of SSL. The LES and DSSL protocols achieve desired end-to-end communication security while allowing the TCP and HTTP proxy servers to function correctly.

Roy-Chowdhury, Ayan↗
NASA NTRS2015

Sole-Source Lighting for Controlled-Environment Agriculture

Since plants on Earth evolved under broad-spectrum solar radiation, anytime they are grown exclusively under electric lighting that does not contain all wavelengths in similar proportion to those in sunlight, plant appearance and size could be uniquely different. Nevertheless, plants have been grown for decades under fluorescent (FL) (1) + incandescent (IN) (2) lamps as a sole source of lighting (SSL), and researchers have become comfortable that, in certain proportions of FL + IN for a given species, plants can appear "normal" relative to their growth outdoors. The problem with using such traditional SSLs for commercial production typically is short lamp lifespans and not obtaining enough photosynthetically active radiation (PAR, 400-700 nm) when desired. These limitations led to supplementation of FL + IN lamp outputs with longer-lived, high-intensity discharge (HID) lamps in growth chambers (3). As researchers became comfortable that mixes of orange-biased high-pressure sodium (HPS) and blue-biased metal halide (MH) HIDs together also could give normal plant growth at higher intensities, growth chambers and phytotrons subsequently were equipped mainly with HID lamps, with their intense thermal output filtered out by ventilated light caps or thermal-controlled water barriers. For the most part, IN and HID lamps have found a home in commercial protected horticulture, usually for night-break photoperiod lighting (IN) or for seasonal supplemental lighting (mostly HPS) in greenhouses. However, lack of economically viable options for SSL have held back aspects of year-round indoor agriculture from taking off commercially.

Controlled-Environment Agriculture↗
NASA NTRS2016

Micrometeorite Impact Test of Flex Solar Array Coupon

Spacecraft with solar arrays operate throughout the near earth environment and are planned for outer planet missions. An often overlooked test condition for solar arrays that is applicable to these missions is micrometeoroid impacts and possibly electrostatic discharge (ESD) events resulting from these impacts. NASA Marshall Space Flight Center (MSFC) is partnering with Space Systems/Loral, LLC (SSL) to examine the results of simulated micrometeoroid impacts on the electrical performance of an advanced, lightweight flexible solar array design. The test is performed at MSFC's Micro Light Gas Gun Facility with SSL-provided coupons. Multiple impacts were induced at various locations on a powered test coupon under different string voltage (0V-150V) and string current (1.1A - 1.65A) conditions. The setup, checkout, and results from the impact testing are discussed.

Wright, K. H.↗
NASA NTRS2016

Micrometeorite Impact Test of Flex Solar Array Coupon

Spacecraft with solar arrays operate throughout the near earth environment and are increasingly planned for outer planet missions. An often overlooked test condition for solar arrays that is applicable to these missions is micrometeorite impacts and possibly electrostatic discharge (ESD) events resulting from these impacts. The Marshall Space Flight Center (MSFC) is partnering with Space Systems/Loral, LLC (SSL) to examine the results of simulated micrometeorite impacts on the electrical performance of an advanced, lightweight flexible solar array design. The test is performed at NASA MSFC's Microlight Gas Gun Facility. The SSL-provided coupons consist of three strings, each string with two solar cells in series. Five impacts will be induced at various locations on a powered test coupon under different string voltage (0 volts - 150 volts) and string current (1.1 amperes - 1.65 amperes) conditions. The maximum specified test voltage and current represent margins of 1.5 times for both voltage and current. The test parameters are chosen to demonstrate new array design robustness to any ESD event caused by plasma plumes resulting from a simulated micrometeorite impact. A second unpowered coupon will undergo two impacts: one impact on the front side and one impact on the back side. Following the impact testing, the second coupon will be exposed to a thermal cycle test to determine possible damage propagation and further electrical degradation due to thermally-induced stress. The setup, checkout, and results from the impact testing are discussed. The challenges for impact testing include precise coupon alignment to control impact location; pressure management during the impact process; and measurement of the true transient electrical response during impact on the powered coupon. Results from pre- and post-test visual and electrical functional testing are also discussed.

Wright, K. H.↗
NASA NTRS2016

Commercial Application of In-Space Assembly

In-Space assembly (ISA) expands the opportunities for cost effective emplacement of systems in space. Currently, spacecraft are launched into space and deploy into their operational configuration through a carefully choreographed sequence of operations. The deployment operation dictates the arrangement of the primary systems on the spacecraft, limiting the ability to take full advantage of launch vehicles volume and mass capability. ISA enables vastly different spacecraft architectures and emplacement scenarios to be achieved, including optimal launch configurations ranging from single launch and assembly to on-orbit aggregation of multiple launches at different orbital locations and times. The spacecraft can be visited at different orbital locations and times to effect expansion and maintenance of an operational capability. To date, the primary application of ISA has been in large programs funded by government organizations, such as the International Space Station. Recently, Space Systems Loral (SSL) led a study funded by the Defense Advanced Research Projects Agency (DARPA), called Dragonfly, to investigate the commercial applicability and economic advantages of ISA. In the study, it was shown that ISA enables SSL to double the capability of a commercial satellite system by taking advantage of alternate packaging approaches for the reflectors. The study included an ultra-light-weight robotic system, derived from Mars manipulator designs, to complete assembly of portions of the antenna system using a tool derived from DARPA orbital express and National Aeronautics and Space Administration (NASA) automated structural assembly experience. The mechanical connector that enables robotic ISA takes advantage of decades of development by NASA from the 1970's to 1980's during the Space Station Freedom program, the precursor to the ISS. The mechanical connector was originally designed for rapid astronaut assembly while also providing a high quality structural connection with linear load deflection response. The paper will discuss the business case for ISA, the general approach taken to exploit on-orbit assembly in the GEO communication satellite market, and the concept of operations associated with the ISA approach, thus laying the foundation for ISA to become an accepted operational approach for commercial in-space operations.

Lymer, John↗
NASA NTRS2015

Low-Power Operation and Plasma Characterization of a Qualification Model SPT-140 Hall Thruster for NASA Science Missions

Hall thruster systems based on commercial product lines can potentially lead to lower cost electric propulsion (EP) systems for deep space science missions. A 4.5-kW SPT-140 Hall thruster presently under qualification testing by SSL leverages the substantial heritage of the SPT-100 being flown on Russian and US commercial satellites. The Jet Propulsion Laboratory is exploring the use of commercial EP systems, including the SPT-140, for deep space science missions, and initiated a program to evaluate the SPT-140 in the areas of low power operation and thruster operating life. A qualification model SPT-140 designated QM002 was evaluated for operation and plasma properties along channel centerline, from 4.5 kW to 0.8 kW. Additional testing was performed on a development model SPT-140 designated DM4 to evaluate operation with a Moog proportional flow control valve (PFCV). The PFCV was commanded by an SSL engineering model PPU-140 Power Processing Unit (PPU). Performance measurements on QM002 at 0.8 kW discharge power were 50 mN of thrust at a total specific impulse of 1250 s, a total thruster efficiency of 0.38, and discharge current oscillations of under 3% of the mean current. Steady-state operation at 0.8 kW was demonstrated during a 27 h firing. The SPT-140 DM4 was operated in closed-loop control of the discharge current with the PFCV and PPU over discharge power levels of 0.8-4.5 kW. QM002 and DM4 test data indicate that the SPT-140 design is a viable candidate for NASA missions requiring power throttling down to low thruster input power.

Garner, Charles E.↗
DOE OSTI2018

Accelerated Stress Testing of Multi-Source LED Products: Horticulture Lamps and Tunable-White Modules

This report discusses the use of accelerated stress testing (AST) to provide insights into the long-term behavior of commercial products utilizing different types of mid-power LEDs (MP-LEDs) integrated into the same LED module. Test results are presented from two commercial lamps intended for use in horticulture applications and one tunable-white LED module intended for use in educational and office lighting applications. Each of these products is designed to provide a custom spectrum for their targeted applications and each achieves this goal in different ways. Consequently, a comparison of the long-term stability of these devices will provide insights regarding approaches that could be used to possibly lengthen the lifetime of SSL products.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2018

Accelerated Stress Testing on Multichannel Drivers—Updated Test Results

This report is the second in a series of studies about accelerated stress testing (AST) of drivers used for SSL luminaires. Two-stage drivers intended for use in downlights, troffers and street lights were selected to undergo exposure to an AST environment consisting of 75°C and 75% relative humidity (7575). The 7575 AST environment was chosen for this study because a previous study demonstrated that 38% of a sample population of 6-inch downlights failed in less than 2,500 hours in these conditions. A mixture of single-channel (i.e., one output current channel designed for use with one LED primary) and multichannel (i.e., separate output current channels designed for use with multiple for LED primaries) two-stage drivers were exposed to the 7575 environment. This report provides updated AST test results for only the multichannel driver products. The multichannel driver population consisted of three products (with two-stage architecture) and a total of five samples. In addition to AST results, the product life distribution (Weibull analysis) of two-stage driver Hammer Test samples is reported.

42 ENGINEERING↗
DOE OSTI2022

2022 Solid-State Lighting R&D Opportunities

This is an updated edition that examines critical opportunities to positively impact energy savings, greenhouse gas emissions, human well-being, and the economy through Solid-State Lighting (SSL) R&D. The document summarizes stakeholder input from DOE-hosted roundtable meetings, workshops, a Request for Information, and other sources.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS2015

Townes Group Activities from 1983-2000: Personal Recollections of William Danchi

I arrived in Berkeley in October 1983 as a post-doc, and my appointment was at the Space Sciences Laboratory (SSL). During that time the group was very large, with multiple activities led by Charlie himself and also by Senior Fellows such as John Lacy, Dan Jaffe, and Al Betz at the top of the hill at Space Sciences. Another significant contingent of the Townes group was housed in Birge Hall on campus, led by Reinhard Genzel when he was an Assistant Professor in the Physics Department. Although the group encompassed two separate locations, it functioned as one large group. Either we rode with Charlie up and down the hill, or (if we were concerned about our safety!) we took the bus.

Space Sciences Laboratory (SSL)↗
DOE OSTI2018

2018 DOE Solid-State Lighting Project Portfolio

The 2018 Solid-State Lighting Project Portfolio provides an overview of all SSL projects that have been funded by DOE since 2000. Projects that were active during 2017 are found in the main body of this report, and all historic projects can be found in the appendix. Within these sections, project profiles are sorted by technology type (i.e., LED or OLED) and then by performer name. A profile is provided on each project. Each profile includes a brief technical description, as well as information about project partners, funding, and the research period. This report is updated annually, although the research described in the Portfolio changes periodically as new projects are initiated and existing ones are concluded.

SSL, lighting, project, LED, OLED, portfolio, awar↗