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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Controller Hardware-in-the-Loop Evaluation of a Microgrid Controller for a Microgrid System with Multiple Grid-Forming Inverters

This paper presents the laboratory evaluation of a commercial Microgrid Management System (MGMS) implemented in the real-world Bronzeville Microgrid which features a futuristic scenario with high renewable energy integration and the use of multiple Grid-Forming (GFM) inverters. The primary objective of the performance evaluation for the MGMS is to assess the MGMS's capability to dispatch GFM units, including a GFM PV unit and two GFM battery units, to maintain the system stability and ensure economic operation, thus guaranteeing the microgrid's resilience during prolonged outages and dynamic events. The laboratory controller hardware-in-the-loop provides realistic testing environment through detailed electromagnetic transient modeling of the microgrid system, hardware MGMS, and standard communication protocols (DNP3). The CHIL evaluation shows how the MGMS effectively manages the GFM inverters, highlighting its performance in maintaining stability, reliability, and survivability in a microgrid environment with a high penetration of renewable energy sources.

controller hardware-in-the-loop↗
DOE OSTI2024

Controller Hardware-in-the-Loop Evaluation of a Microgrid Controller for a Microgrid System with Multiple Grid-Forming Inverters: Preprint

This paper presents the laboratory evaluation of a commercial Microgrid Management System (MGMS) implemented in the real-world Bronzeville Microgrid which features a futuristic scenario with high renewable energy integration and the use of multiple Grid-Forming (GFM) inverters. The primary objective of the performance evaluation for the MGMS is to assess the MGMS's capability to dispatch GFM units, including a GFM PV unit and two GFM battery units, to maintain the system stability and ensure economic operation, thus guaranteeing the microgrid's resilience during prolonged outages and dynamic events. The laboratory controller hardware-in-the-loop provides realistic testing environment through detailed electromagnetic transient modeling of the microgrid system, hardware MGMS, and standard communication protocols (DNP3). The CHIL evaluation shows how the MGMS effectively manages the GFM inverters, highlighting its performance in maintaining stability, reliability, and survivability in a microgrid environment with a high penetration of renewable energy sources.

controller hardware-in-the-loop↗
NASA NTRS1961

Project Echo: Standby Receiver System

The Echo I satellite receiving system at the Bell Telephone Laboratories facilities at Holmdel, New Jersey, required a 2390-Mc standby receiver system to maintain operation during possible failures of the primary maser receiver. This paper describes the details of the two matched parametric amplifiers that were used to provide the standby receiver. The use of this system in the initial Moonbounce experiments and in Project Echo is described. The details of an emergency operation at the beginning of a balloon pass are also presented.

Kibler, L. U.↗
NASA NTRS2005

Rotational spectroscopy at the Jet Propulsion Laboratory

Environmental monitoring, atmospheric remote sensing and astrophysical studies promoted by NASA require a strong basis of spectroscopic information. The rotational spectroscopy capabilities at NASAs Jet Propulsion Laboratory (JPL) are currently maintained for the measurement of key mission priorities that enable modeling and retrieval of geophysical data from the atmosphere as well as validation of the space-borne instruments in the Earth Observing System, particularly the Microwave Limb Sounder. Rotational spectra are measured using a variety of spectroscopic techniques including pulsed-beam Fourier transform microwave spectroscopy (at CalTech); millimeter wavelength Stark spectroscopy; millimeter, submillimeter and THz FM spectroscopy; laser sideband spectroscopy and Fourier Transform far-infrared spectroscopy. Remote measurements of atmospheric rotational spectra are made using two limb-sounder instruments in the submillimeter and THz. Recent advances in the direct synthesis of THz radiation that enable more efficient laboratory science will be presented. Software for comprehensive and systematic study of different molecular systems is maintained at JPL, the software is freely available via http://spec.jpl.nasa.gov and is used by our group to create and sustain the JPL spectral line catalog also available online.

molecular spectroscopy↗
NASA NTRS2011

A Possible Approach for Addressing Neglected Human Factors Issues of Systems Engineering

The increasing complexity of safety-critical applications has led to the introduction of decision support tools in the transportation and process industries. Automation has also been introduced to support operator intervention in safety-critical applications. These innovations help reduce overall operator workload, and filter application data to maximize the finite cognitive and perceptual resources of system operators. However, these benefits do not come without a cost. Increased computational support for the end-users of safety-critical applications leads to increased reliance on engineers to monitor and maintain automated systems and decision support tools. This paper argues that by focussing on the end-users of complex applications, previous research has tended to neglect the demands that are being placed on systems engineers. The argument is illustrated through discussing three recent accidents. The paper concludes by presenting a possible strategy for building and using highly automated systems based on increased attention by management and regulators, improvements in competency and training for technical staff, sustained support for engineering team resource management, and the development of incident reporting systems for infrastructure failures. This paper represents preliminary work, about which we seek comments and suggestions.

Johnson, Christopher W.↗
NASA NTRS1984

Optimization of thermal systems with sensitive optics, electronics, and structures

A strategy was investigated by which thermal designers for spacecraft could devise an optimal thermal control system to maintain the required temperatures, temperature differences, changes in temperature, and changes in temperature differences for specified equipment and elements of the spacecraft's structure. Thermal control is to be maintained by the coating pattern chosen for the external surfaces and heaters chosen to supplement the coatings. The approach is to minimize the thermal control power, thereby minimizing the weight of the thermal control system. Because there are so many complex computations involved in determining the optimal coating design a computerized approach was contemplated. An optimization strategy including all the elements considered by the thermal designer for use in the early stages of design, where impact on the mission is greatest, and a plan for implementing the strategy were successfully developed. How the optimization process may be used to optimize the design of the Space Telescope as a test case is demonstrated.

Bettini, R. G.↗
NASA NTRS2013

Data Mining for Understanding and Improving Decision-making Affecting Ground Delay Programs

The continuous growth in the demand for air transportation results in an imbalance between airspace capacity and traffic demand. The airspace capacity of a region depends on the ability of the system to maintain safe separation between aircraft in the region. In addition to growing demand, the airspace capacity is severely limited by convective weather. During such conditions, traffic managers at the FAA's Air Traffic Control System Command Center (ATCSCC) and dispatchers at various Airlines' Operations Center (AOC) collaborate to mitigate the demand-capacity imbalance caused by weather. The end result is the implementation of a set of Traffic Flow Management (TFM) initiatives such as ground delay programs, reroute advisories, flow metering, and ground stops. Data Mining is the automated process of analyzing large sets of data and then extracting patterns in the data. Data mining tools are capable of predicting behaviors and future trends, allowing an organization to benefit from past experience in making knowledge-driven decisions.

Weather↗
NASA NTRS2013

Data Mining for Understanding and Impriving Decision-Making Affecting Ground Delay Programs

The continuous growth in the demand for air transportation results in an imbalance between airspace capacity and traffic demand. The airspace capacity of a region depends on the ability of the system to maintain safe separation between aircraft in the region. In addition to growing demand, the airspace capacity is severely limited by convective weather. During such conditions, traffic managers at the FAA's Air Traffic Control System Command Center (ATCSCC) and dispatchers at various Airlines' Operations Center (AOC) collaborate to mitigate the demand-capacity imbalance caused by weather. The end result is the implementation of a set of Traffic Flow Management (TFM) initiatives such as ground delay programs, reroute advisories, flow metering, and ground stops. Data Mining is the automated process of analyzing large sets of data and then extracting patterns in the data. Data mining tools are capable of predicting behaviors and future trends, allowing an organization to benefit from past experience in making knowledge-driven decisions. The work reported in this paper is focused on ground delay programs. Data mining algorithms have the potential to develop associations between weather patterns and the corresponding ground delay program responses. If successful, they can be used to improve and standardize TFM decision resulting in better predictability of traffic flows on days with reliable weather forecasts. The approach here seeks to develop a set of data mining and machine learning models and apply them to historical archives of weather observations and forecasts and TFM initiatives to determine the extent to which the theory can predict and explain the observed traffic flow behaviors.

data mining↗
NASA NTRS2000

Kepler Mission: End-to-End System Demonstration

A test facility has been constructed to demonstrate the capability of differential ensemble photometry to detect transits of Earth-size planets orbiting solar-like stars. The main objective is to determine the effects of various noise sources on the capability of a CCD photometer to maintain a system relative precision of 1 x $10^(-5)$ for mv = 12 stars in the presence of system-induced noise sources. The facility includes a simulated star field, fast optics to simulate the telescope, a thinned back-illuminated CCD similar to those to be used on the spacecraft and computers to perform the onboard control, data processing and extraction. The test structure is thermally and mechanically isolated so that each source of noise can be introduced in a controlled fashion and evaluated for its contribution to the total noise budget. The effects of pointing errors or a changing thermal environment are imposed by piezo-electric devices. Transits are injected by heating small wires crossing apertures in the star plate. Signals as small as those from terrestrial-size transits of solar-like stars are introduced to demonstrate that such planets can be detected under realistic noise conditions. Examples of imposing several noise sources and the resulting detectabilities are presented. These show that a differential ensemble photometric approach CCD photometer can readily detect signals associated with Earth-size transits.

Borucki, William↗
NASA NTRS1975

Thermal design and test of a high power spacecraft transponder platform

The high power transponder subsystem on board the Communications Technology Satellite (CTS) requires some unique thermal control techniques to maintain the required temperature limits throughout all mission phases. The transponder subsystem includes redundant 20-W output travelling wave tubes and a single 200-W output TWT with highly concentrated thermal dissipations of 70 W and 143 W, respectively. A thermal control system which maintains all components within the required temperature ranges has been designed and verified in thermal balance testing. Included in the design are second surface quartz mirrors on an aluminum honeycomb platform, high thermal conductivity aluminum doubler plates, commandable thermal control heaters and a Variable Conductance Heat Pipe System (VCHPS).

Stipandic, E. A.↗
NASA NTRS2004

Practical Pocket PC Application w/Biometric Security

I work in the Flight Software Engineering Branch, where we provide design and development of embedded real-time software applications for flight and supporting ground systems to support the NASA Aeronautics and Space Programs. In addition, this branch evaluates, develops and implements new technologies for embedded real-time systems, and maintains a laboratory for applications of embedded technology. The majority of microchips that are used in modern society have been programmed using embedded technology. These small chips can be found in microwaves, calculators, home security systems, cell phones and more. My assignment this summer entails working with an iPAQ HP 5500 Pocket PC. This top-of-the-line hand-held device is one of the first mobile PC's to introduce biometric security capabilities. Biometric security, in this case a fingerprint authentication system, is on the edge of technology as far as securing information. The benefits of fingerprint authentication are enormous. The most significant of them are that it is extremely difficult to reproduce someone else's fingerprint, and it is equally difficult to lose or forget your own fingerprint as opposed to a password or pin number. One of my goals for this summer is to integrate this technology with another Pocket PC application. The second task for the summer is to develop a simple application that provides an Astronaut EVA (Extravehicular Activity) Log Book capability. The Astronaut EVA Log Book is what an astronaut would use to report the status of field missions, crew physical health, successes, future plans, etc. My goal is to develop a user interface into which these data fields can be entered and stored. The applications that I am developing are created using eMbedded Visual C++ 4.0 with the Pocket PC 2003 Software Development Kit provided by Microsoft.

Logan, Julian↗
NASA NTRSDate not supplied

Human-in-the-Loop Flight Simulation Experiment on Unmanned Aircraft Terminal Operations

A Detect and Avoid (DAA) System is a suite of sensors, tracker, and alerting and guidance algorithms that assist a remote pilot of an Unmanned Aircraft System in maintaining separation from airborne traffic by complying with current ‘see and avoid’ requirements. To date, work has focused on operations transiting to and from Class A or special use airspace. Current efforts are defining DAA system requirements for operations in and around terminal airspace. As a contribution to the current efforts, this paper presents results from a Human-in-the-Loop experiment comparing methods of changing from the transit-specific alerting and guidance criteria to the reduced terminal-specific alerting and guidance criteria.

Devin Patrick Jack↗
NASA NTRS2004

Hierarchical Discrete Event Supervisory Control of Aircraft Propulsion Systems

This paper presents a hierarchical application of Discrete Event Supervisory (DES) control theory for intelligent decision and control of a twin-engine aircraft propulsion system. A dual layer hierarchical DES controller is designed to supervise and coordinate the operation of two engines of the propulsion system. The two engines are individually controlled to achieve enhanced performance and reliability, necessary for fulfilling the mission objectives. Each engine is operated under a continuously varying control system that maintains the specified performance and a local discrete-event supervisor for condition monitoring and life extending control. A global upper level DES controller is designed for load balancing and overall health management of the propulsion system.

Yasar, Murat↗
NASA NTRS2016

In-Process Thermal Imaging of the Electron Beam Freeform Fabrication Process

Researchers at NASA Langley Research Center have been developing the Electron Beam Freeform Fabrication (EBF3) metal additive manufacturing process for the past 15 years. In this process, an electron beam is used as a heat source to create a small molten pool on a substrate into which wire is fed. The electron beam and wire feed assembly are translated with respect to the substrate to follow a predetermined tool path. This process is repeated in a layer-wise fashion to fabricate metal structural components. In-process imaging has been integrated into the EBF3 system using a near-infrared (NIR) camera. The images are processed to provide thermal and spatial measurements that have been incorporated into a closed-loop control system to maintain consistent thermal conditions throughout the build. Other information in the thermal images is being used to assess quality in real time by detecting flaws in prior layers of the deposit. NIR camera incorporation into the system has improved the consistency of the deposited material and provides the potential for real-time flaw detection which, ultimately, could lead to the manufacture of better, more reliable components using this additive manufacturing process.

Taminger, Karen M.↗
NASA NTRS1989

Development of a precision, wide-dynamic-range actuator for use in active optical systems

The design, operation, and performance of a wide-dynamic-range optical-quality actuator are discussed. The actuator uses a closed-loop control system to maintain accurate positioning and has an rms noise performance of 20 nm. A unique force offloading mechanism allows the actuator coil to dissipate less than 3 mW under quiescent conditions. The operation of an experimental segmented optical system that uses 18 of the actuators is examined to show how they are integrated into an actual system.

Lorell, K. R.↗
NASA NTRS2016

A Hybrid Mars Ascent Vehicle Concept for Low Temperature Storage and Operation

A hybrid propulsion system presents many advantages for a potential Mars Ascent Vehicle including high specific impulse, restartability and predicted excellent low temperature survivability. This additional benefit of low temperature storage and operation could substantially reduce the power required to maintain the system while on Mars and therefore decrease the total landed system mass required for the system. A new wax-based hybrid fuel has been formulated to realize these low temperature benefits, while still preserving high performance (Isp). The freezing point of the oxidizer can be selected to match the capabilities of the fuel, in this case Mixed Oxides of Nitrogen has been selected. The main disadvantages of this system are associated with the relatively low technology readiness level of the selected hybrid propulsion system for operation on Mars. However, technology development efforts are currently underway to advance the hybrid propulsion system to a level where it could potentially compete with heritage propulsion systems. An internal study completed at JPL in 2015 identified the single stage to orbit hybrid MAV as the lowest gross liftoff mass case from a large range of potential propulsion systems. Updates to this design are presented here.

Karp, Ashley Chandler↗
NASA NTRS1996

Use of CCSDS and OSI Protocols on the Advanced Communications Technology Satellite

Although ACTS (Advanced Communications Technology Satellite) provides an almost error-free channel during much of the day and under most conditions, there are times when it is not suitable for reliably error-free data communications when operating in the uncoded mode. Because coded operation is not always available to every earth station, measures must be taken in the end system to maintain adequate throughput when transferring data under adverse conditions. The most effective approach that we tested to improve performance was the addition of an 'outer' Reed-Solomon code through use of CCSDS (Consultative Committee for Space Data Systems) GOS 2 (a forward error correcting code). This addition can benefit all users of an ACTS channel including those applications that do not require totally reliable transport, but it is somewhat expensive because additional hardware is needed. Although we could not characterize the link noise statistically (it appeared to resemble uncorrelated white noise, the type that block codes are least effective in correcting), we did find that CCSDS GOS 2 gave an essentially error-free link at BER's (bit error rate) as high as 6x10(exp -4). For users that demand reliable transport, an ARQ (Automatic Repeat Queuing) protocol such as TCP (Transmission Control Protocol) or TP4 (Transport Protocol, Class 4) will probably be used. In this category, it comes as no surprise that the best choice of the protocol suites tested over ACTS was TP4 using CCSDS GOS 2. TP4 behaves very well over an error-free link which GOS 2 provides up to a point. Without forward error correction, however, TP4 service begins to degrade in the 10(exp -7)-10(exp -6) range and by 4x10(exp -6), it barely gives any throughput at all. If Congestion Avoidance is used in TP4, the degradation is even more pronounced. Fortunately, as demonstrated here, this effect can be more than compensated for by choosing the Selective Acknowledgment option. In fact, this option can enable TP4 to deliver some throughput at error rates as high as 10(exp -5).

Chirieleison, Don↗
NASA NTRS1998

Two Wavelength Ti:sapphire Laser for Ozone DIAL Measurements from Aircraft

Laser remote sensing of ozone from aircraft has proven to be a valuable technique for understanding the distribution and dynamics of ozone in the atmosphere. Presently the differential absorption lidar (DIAL) technique, using dual ND:YAG lasers that are doubled to pump dye lasers which in turn are doubled into the UV for the "on" and "off' line lasers, is used on either the NASA DC-8 or P-3 aircraft. Typically, the laser output for each line is 40-mJ and this is split into two beams, one looking up and the other downward, each beam having about 20-mJ. The residual ND:YAG (1.06 micron) and dye laser energies are also transmitted to obtain information on the atmospheric aerosols. While this system has operated well, there are several system characteristics that make the system less than ideal for aircraft operations. The system, which uses separate "on" and "off" line lasers, is quite large and massive requiring valuable aircraft volume and weight. The dye slowly degrades with time requiring replacement. The laser complexity requires a number of technical people to maintain the system performance. There is also the future interest in deploying an ozone DIAL system in an Unpiloted Atmospheric Vehicle (UAV) which would require a total payload mass of less than 150 kg and power requirement of less than 1500 W. A laser technology has emerged that could potentially provide significant enhancements over the present ozone DIAL system. The flashlamp pumped Ti:sapphire laser system is an emerging technology that could reduce the mass and volume over the present system and also provide a system with fewer conversion steps, reducing system complexity. This paper will discuss preliminary results from a flashlamp-pumped Ti:sapphire laser constructed as a radiation source for a UV DIAL system to measure ozone.

Situ, Wen↗