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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 613 records · Page 34

All sources NASA NTRS DOE OSTI

NASA NTRS2009

A Deep Space Network Portable Radio Science Receiver

The Radio Science Receiver (RSR) is an open-loop receiver installed in NASA s Deep Space Network (DSN), which digitally filters and records intermediate-frequency (IF) analog signals. The RSR is an important tool for the Cassini Project, which uses it to measure perturbations of the radio-frequency wave as it travels between the spacecraft and the ground stations, allowing highly detailed study of the composition of the rings, atmosphere, and surface of Saturn and its satellites.

Jongeling, Andre P.↗

NASA NTRS2011

Coherent Doppler Lidar for Precision Navigation of Spacecrafts

A fiber-based coherent Doppler lidar, utilizing an FMCW technique, has been developed and its capabilities demonstrated through two successful helicopter flight test campaigns. This Doppler lidar is expected to play a critical role in future planetary exploration missions because of its ability in providing the necessary data for soft landing on the planetary bodies and for landing missions requiring precision navigation to the designated location on the ground. Compared with radars, the Doppler lidar can provide significantly higher precision velocity and altitude data at a much higher rate without concerns for measurement ambiguity or target clutter. Future work calls for testing the Doppler lidar onboard a rocket-powered free-flyer platform operating in a closed-loop with the vehicle s guidance, navigation, and control (GN&C) unit.

Amzajerdian, Farzin↗

NASA NTRSDate not supplied

Predictive Workload Model for Air Traffic Controllers during UAM Operations

The effect of airspace factors on air traffic controller (ATC) workload has been an active area of study for almost three decades due to the importance of safety considerations necessary to design and maintain operations. Existing literature has examined several traffic-related (e.g., number of aircraft under control, loss of separation) contributors to ATC workload and proposed mathematical functions to best describe controller response. However, future air traffic continues to increase in complexity with the introduction of urban air mobility (UAM) – or the transportation of humans and cargo using electric vertical takeoff and landing (eVTOL) aircraft. UAM aims to alleviate congestion for existing ground transportation systems and improve mobility within urban centers and other high-demand locations. This shift in the traditional airspace paradigm necessitates an evolved understanding of model use and development for ATC workload prediction. This study aimed to develop an ATC workload forecasting model based on human-in-the-loop (HITL) simulation data for UAM operations at large airports. Data collected from the HITL simulation served as the training and testing data for a Long Short-Term Memory recurrent neural network and enabled time-series forecasting of ATC workload from traffic characteristics. Results demonstrated the potential of LSTM models for forecasting ATC workload 40 minutes into the future and highlighted important considerations for future development.

predictive model↗

NASA NTRSDate not supplied

Predictive Workload Model for Air Traffic Controllers during UAM Operations

predictive model↗

DOE OSTI2011

Results on Searches for New Physics at B Factories

We summarize recent results on B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}} setting constraints on the charged Higgs mass, discuss the CP puzzle in B {yields} K{pi} decays and present searches for a light neutral Higgs in radiative {Upsilon}(2S) and {Upsilon}(3S) decays. Rare decays are processes with branching fractions of {Omicron}(10{sup -4}) or smaller. Typically, they arise if amplitudes of higher-order processes (penguin loops, box diagrams) become dominant because tree amplitudes are suppressed in the Standard Model (SM). Additional suppression comes from small CKM couplings and helicity conservation. Contributions of New Physics (NP) processes may become significant modifying the prediction with respect to those in the SM. Thus, rare decays provide an interesting hunting ground for NP searches that are complementary to direct searches at the LHC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS2015

Pressure Profiles in a Loop Heat Pipe Under Gravity Influence

During the operation of a loop heat pipe (LHP), the viscous flow induces pressure drops in various elements of the loop. The total pressure drop is equal to the sum of pressure drops in vapor grooves, vapor line, condenser, liquid line and primary wick, and is sustained by menisci at liquid and vapor interfaces on the outer surface of the primary wick in the evaporator. The menisci will curve naturally so that the resulting capillary pressure matches the total pressure drop. In ground testing, an additional gravitational pressure head may be present and must be included in the total pressure drop when LHP components are placed in a non-planar configuration. Under gravity-neutral and anti-gravity conditions, the fluid circulation in the LHP is driven solely by the capillary force. With gravity assist, however, the flow circulation can be driven by the combination of capillary and gravitational forces, or by the gravitational force alone. For a gravity-assist LHP at a given elevation between the horizontal condenser and evaporator, there exists a threshold heat load below which the LHP operation is gravity driven and above which the LHP operation is capillary force and gravity co-driven. The gravitational pressure head can have profound effects on the LHP operation, and such effects depend on the elevation, evaporator heat load, and condenser sink temperature. This paper presents a theoretical study on LHP operations under gravity neutral, anti-gravity, and gravity-assist modes using pressure diagrams to help understand the underlying physical processes. Effects of the condenser configuration on the gravitational pressure head and LHP operation are also discussed.

0000↗

NASA NTRS2015

Pressure Profiles in a Loop Heat Pipe under Gravity Influence

During the operation of a loop heat pipe (LHP), the viscous flow induces pressure drops in various elements of the loop. The total pressure drop is equal to the sum of pressure drops in vapor grooves, vapor line, condenser, liquid line and primary wick, and is sustained by menisci at liquid and vapor interfaces on the outer surface of the primary wick in the evaporator. The menisci will curve naturally so that the resulting capillary pressure matches the total pressure drop. In ground testing, an additional gravitational pressure head may be present and must be included in the total pressure drop when LHP components are placed in a non-planar configuration. Under gravity-neutral and anti-gravity conditions, the fluid circulation in the LHP is driven solely by the capillary force. With gravity assist, however, the flow circulation can be driven by the combination of capillary and gravitational forces, or by the gravitational force alone. For a gravity-assist LHP at a given elevation between the horizontal condenser and evaporator, there exists a threshold heat load below which the LHP operation is gravity driven and above which the LHP operation is capillary force and gravity co-driven. The gravitational pressure head can have profound effects on the LHP operation, and such effects depend on the elevation, evaporator heat load, and condenser sink temperature. This paper presents a theoretical study on LHP operations under gravity-neutral, anti-gravity, and gravity-assist modes using pressure diagrams to help understand the underlying physical processes. Effects of the condenser configuration on the gravitational pressure head and LHP operation are also discussed.

Thermal Control Systems↗

DOE OSTI2012

Photon-graviton amplitudes from the effective action

We report on the status of an ongoing effort to calculate the complete one-loop low-energy effective actions in Einstein-Maxwell theory with a massive scalar or spinor loop, and to use them for obtaining the explicit form of the corresponding M -graviton/ N -photon amplitudes. We present explicit results for the effective actions at the one-graviton four-photon level, and for the amplitudes at the one-graviton two-photon level. As expected on general grounds, these amplitudes relate in a simple way to the corresponding four-photon amplitudes. We also derive the gravitational Ward identity for the 1PI one-graviton- N photon amplitude.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

NASA NTRS1977

A high accuracy gyroscope readout test facility for the relativity gyroscope experiment

An apparatus is under construction for ground-based testing of a gyroscope system to be used in a satellite test of general relativity. The immediate goal is a readout capable of measuring the direction of the gyroscope spin axis to an angular resolution of one arcsecond over a limited range. A combination of SQUID magnetometers and persistent current loops are used to measure the London moment of the spinning superconducting rotor levitated electrostatically. To obtain a trapped flux signal in the gyroscope sufficiently smaller than the London moment signal, the apparatus makes use of a new magnetic field shielding technique for obtaining large superconductor shielded regions below 0.1 millionth of a Gauss.

Cabrera, B.↗

NASA NTRS1988

Controls and guidance: Space

The Space Controls and Guidance Research and Technology Program is directed toward enabling the next generation of space transportation systems, large future spacecraft, and space systems such as the Space Station to have large communication antennas and high precision segmented reflector astrophysical telescopes. The new generation of transportation vehicles has demanding requirements to provide for an order of magnitude reduction in cost as well as an increase in capability. The future orbital facilities have demanding control requirements for pointing and stabilization, momentum management, build-up and growth accomodation, and disturbance management. To address these advanced requirements, the research and development program is designed to provide the generic technology base to support the implementation of advanced guidance, navigation, and control. The area of computational controls will be stressed in order to develop cost effective, high speed, high fidelity control system simulation and analysis and synthesis tools. The trust of this work will be to develop methods and software to enable analysis and real-time hardware-in-the-loop simulation of complex spacecraft for control design certification. To address future orbital facilities requirements, an advanced technology program is underway in system identification, distributed control, integrated controls/structures design methods, and advanced sensors and actuators. Because the behavior of large, light weight per unit area deployable/assembled spacecraft is greatly influenced by the ground environment, the testing and verification activity is both ground- and space-based.

Dibattista, John D.↗

NASA NTRS1988

Supernovae and supernova remnants

The basic features and astrophysics of supernovae of types Ia, Ib, and II and of SNRs are discussed, summarizing the results of recent ground-based and space observations obtained at different wavelengths. Typical data are presented in graphs and sample images, and consideration is given to their implications for shock heating by the initial explosion, radioactive energy input, circumstellar interaction, and pulsar energy input. SNRs described include Tycho's remnant, Kepler's remnant, the Cyg loop, Pup A, the Crab Nebula, the Vela and Crab pulsars, and 0540-69.3 in the LMC. The need for high-spatial-resolution IR and X-ray spectra of these objects is indicated.

Chevalier, Roger A.↗

NASA NTRS1995

The NASA landing gear test airplane

A tire and landing gear test facility has been developed and incorporated into a Convair 990 aircraft. The system can simulate tire vertical load profiles to 250,000 lb, sideslip angles to 15 degrees, and wheel braking on actual runways. Onboard computers control the preprogrammed test profiles through a feedback loop and also record three axis loads, tire slip angle, and tire condition. The aircraft to date has provided tire force and wear data for the Shuttle Orbiter tire on three different runways and at east and west coast landing sites. This report discusses the role of this facility in complementing existing ground tire and landing gear test facilities, and how this facility can simultaneously simulate the vertical load, tire slip, velocity, and surface for an entire aircraft landing. A description is given of the aircraft as well as the test system. An example of a typical test sequence is presented. Data collection and reduction from this facility are discussed, as well as accuracies of calculated parameters. Validation of the facility through ground and flight tests is presented. Tests to date have shown that this facility can operate at remote sites and gather complete data sets of load, slip, and velocity on actual runway surfaces. The ground and flight tests have led to a successful validation of this test facility.

Carter, John F.↗

NASA NTRS2017

Getting Out of Orbit: Water Recycling Requirements and Technology Needs for Long Duration Missions Away from Earth

Deep-space crewed missions will not have regular access to the Earth's resources or the ability to rapidly return to Earth if a system fails. As crewed missions extend farther from Earth for longer periods, habitation systems must become more self-sufficient and reliable for safe, healthy, and sustainable human exploration. For human missions to Mars, Environmental Control and Life Support Systems (ECLSS) must be able operate for up to 1,100 days with minimal spares and consumables. These missions will require capabilities to more fully recycle atmospheric gases and wastewater to substantially reduce mission costs. Even with relatively austere requirements for use, water represents one of the largest consumables by mass. Systems must be available to extract and recycle water from all sources of waste. And given that there will be no opportunity to send samples back to Earth for analysis, analytical measurements will be limited to monitoring hardware brought on board the spacecraft. The Earth Reliant phase of NASA's exploration strategy includes leveraging the International Space Station (ISS) to demonstrate advanced capabilities for a robust and reliable ECLSS. The ISS Water Recovery System (WRS) includes a Urine Processor Assembly (UPA) for distillation and recovery of water from urine and a Water Processor Assembly (WPA) to process humidity condensate and urine distillate into potable water. Possible enhancements to more fully "close the water loop" include recovery of water from waste brines and solid wastes. A possible game changer is the recovery of water from local planetary resources through use of In Situ Resource Utilization (ISRU) technologies. As part of the development and demonstration sequence, NASA intends to utilize cis-Lunar space as a Proving Ground to verify systems for deep space habitation by conducting extended duration missions to validate our readiness for Mars.

Barta, Daniel J.↗

NASA NTRS2019

Challenges Using the Linux Network Stack for Real-Time Communication

Starting in the early 2000s, human-in-the-loop (HITL) simulation groups at NASA and the Air Force Research Lab began using the Linux network stack for some real-time communication. More recently, SpaceX has adopted Ethernet as the primary bus technology for its Falcon launch vehicles and Dragon capsules. As the Linux network stack makes its way from ground facilities to flight critical systems, it is necessary to recognize that the network stack is optimized for communication over the open Internet, which cannot provide latency guarantees. The Internet protocols and their implementation in the Linux network stack contain numerous design decisions that favor throughput over determinism and latency. These decisions often require workarounds in the application or customization of the stack to maintain a high probability of low latency on closed networks, especially if the network must be fault tolerant to single event upsets.

Madden, Michael M.↗

NASA NTRS2021

Capabilities and Performance of Juno’s Radio Science Instrumentation

The Juno Gravity Science Instrument is a radio science instrument onboard the Juno spacecraft, which entered orbit around Jupiter in 2016. The prime objective of the radio science investigation is to estimate the gravitational field of Jupiter from the Doppler shift on the radio link between the spacecraft and the Earth-based observing antennas of NASA’s Deep Space Network (DSN). The instrument is composed of a ground component at the DSN’s DSS-25 antenna, equipped with simultaneous dual X- and Ka-band transmitters and receivers, and a spacecraft component, which includes X- and Ka-band transponders to relay the transmitted signal back to Earth. The frequencies of these signals are measured using sensitive open-loop and closed-loop receivers of the DSN. Using the unique geometry of Juno’s orbit around Jupiter and the exquisite precision of the radio science instrumentation (~5-10 microns/sec one-way), the gravity field of Jupiter has been probed to unprecedented precision, allowing for discoveries of Jupiter’s core size and depth of the zonal winds. This precision is thanks to a detailed data processing and calibration techniques. An Advanced Water Vapor Radiometer measures the tropospheric delay and a linear combination X- and Ka-band links calibrates for Earth ionosphere, solar plasma, and Jovian plasma. Recent measurements probed the electron content inside Jupiter’s Io Plasma Torus, a doughnut-shaped ring of charged particles caught in Jupiter’s magnetosphere. Results from these measurements not only contributes to the scientific literature but also informs the performance of the instrument itself and can be used in future planning.

Oudrhiri, Kamal↗

DOE OSTI2024

Carbondale Community Geothermal Coalition – Replicable Models for Decarbonizing Mixed-Use Rural Communities

The Carbondale Community Geothermal Coalition (CCGC) set out to prove that a fifth-generation geothermal district heating & cooling (5G GDHC) network can be technically feasible, cost-effective, and socially equitable for a small, mixed-use rural community. During Budget Period 1 (Planning & Design) the team: ● Completed a 449 ft thermal-response test confirming excellent ground conductivity (k = 1.69 Btu ft -1 hr -1 °F -1 ) and a benign 56.3 °F undisturbed temperature. Page 1 Final Technical Report for Award Number: DE-EE0010663 ● Built a fully calibrated digital twin (URBANopt → Modelica) for 240 k ft 2 of existing + future buildings. ● Designed a 75-borehole ambient-temperature loop (ATL) augmented by 75 solar-thermal panels, supplying 44 % of district heating and 100 % cooling in Stage-1. ● Produced retrofit bid-ready drawings for the Third Street Center and Second Street Townhomes. ● Reached > 200 community stakeholders and exceeded equity targets (46 % Hispanic/Latinx participation). ● Drafted a multi-tiered workforce plan aligned with Colorado Mountain College (Hispanic Serving Institution) and IGSHPA certifications.

15 GEOTHERMAL ENERGY↗

NASA NTRS1987

Flight test of a digital controller used in a helicopter autoland system

This paper describes the flight test evaluation of an advanced digital helicopter flight control system. The controller was designed using an optimal control design procedure for a fully coupled lateral and longitudinal vehicle model. Explicit integrals of the guidance error were included to produce a type 1 characteristic. Gain scheduling was used to account for changes in the vehicle dynamics. The digital controller was exercised by combining it with state estimators, a trajectory generator, and a closed-loop guidance algorithm to form a helicopter autoland system. A CH-47 tandem rotor helicopter was equipped with sensors, on-board digital flight computers, and electrohydraulic actuators. The system was exercised by automatically flying straight-in descending decelerating trajectories typcial of VFR manual landing approaches. A description of the test-ground facilities, the flight hardware and software, and the velocity and position tracking performance is included.

Downing, David R.↗

NASA NTRS1990

Overview of the NASA AMES-Dryden Integrated Test Facility

The Integrated Test Facility (ITF), being built at the NASA Ames Research Center's Dryden Flight Research Facility (ADFRF), will provide new real-time test capabilities for emerging research aircraft. An overview of the ITF and the real-time systems being developed to operate this unique facility are outlined in this paper. The ITF will reduce flight test risk by minimizing the difference between the flight- and ground-test environments. The ground-test environment is provided by combining real-time flight simulation with the actual aircraft. The generic capabilities of the ITF real-time systems, the real-time data recording, and the remotely augmented vehicle (RAV) monitoring system will be discussed. The benefits of applying simulation to aircraft-in-the-loop testing and RAV monitoring system capabilities to the X-29A flight research program will also be discussed.

Mackall, Dale↗