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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Horn Location Sensors for LBNF

The Horn Location Sensor (HLS) system—named for the magnetic focusing horns it monitors, along with other critical beamline elements – is a high-precision alignment system developed for the Long-Baseline Neutrino Facility (LBNF) to support the Deep Underground Neutrino Experiment (DUNE). With minimal maintenance, the HLS can operate reliably in environments with high radiation, and it ensures that key components such as the protective baffle, focusing horns, and beam position monitors are aligned correctly – each essential for maintaining one of the world’s most intense muon-neutrino beams. A high-precision hydrostatic level sensor, a linear variable differential transformer, and INVAR rods are all used in the system to monitor vertical motion and tilt with sub-millimeter accuracy. A novel Sweep Tracker interferometer enhances calibration fidelity by correcting for non-linearities in laser wavelength and scan rate in real time. A critical part of DUNE’s precision alignment and flux prediction requirements, the HLS system initially supports beam power of up to 1.2 MW and can be upgraded to 2.4 MW.

Frequency scanning interferometry↗
NASA NTRS2022

Development of LISA Laser System at NASA

NASA Goddard Space Flight Center (GSFC) is developing a master oscillator power amplifier (MOPA) laser transmitter for the Laser Interferometer Space Antenna (LISA) mission. The laser transmitter is one of the potential contributions to the LISA mission from NASA. Our development effort has included a master oscillator (MO), a power amplifier (PA), a frequency reference system (FRS), a power monitor detector (PMON), and laser electronics module (LEM). We are working on their design, performance evaluation, environmental testing, and reliability testing for space flight. We have built TRL 4 laser optical modules based on the MO and PA, which meets most performance requirements. One of the TRL 4 laser optical modules has been delivered to ESA for independent evaluation. TRL 6 versions of MO and PA are being built and evaluated at GSFC. TRL 5 and 6 versions of laser electronics are under development. In this paper, we will describe our progress to date and plans to demonstrate and deliver a TRL 6 laser demonstrator system to ESA by 2024.

LISA, Space Lasers↗
NASA NTRS1992

A dual purpose optical truss laser metrology system for a space-based far-IR segmented telescope: Figure maintenance and pointing control

To obtain imaging performance as for monolithic mirrors, large segmented reflectors used for astronomy must be actively aligned and pointed to extreme levels of precision. A system concept for a dual purpose optical truss laser metrology system is described which is used for both figure and alignment maintenance and telescope pointing. A two-stage figure active control approach was developed for several proposed spaceborne far infrared segmented telescopes, one of which is the 10-20 meters Large Deployable Reflector (LDR). The first active control stage, the figure initialization control system, aligns the optical elements (i.e., the primary segments, secondary and focal plane assembly) based on images obtained. The second stage, the figure maintenance control system, maintains the alignment between re-initializations using measurements provided by laser interferometers arranged in an optical truss configuration. It measures the relative positions and alignments of the telescope segments so that a controller can reposition them appropriately. The application of this optical truss for figure maintenance control is the subject of the first part of this paper. The second portion of this paper discusses the application of the optical truss to telescope pointing. Here, the laser metrology system is used to transfer pointing information from an external fine guidance sensor (FGS) to the telescope optical boresight as defined by the primary mirror, secondary mirror, and focal plane assembly. Thus, any alignment variations between the two boresights can be observed and accounted for.

Lau, Kenneth↗
NASA NTRS1970

System automatically tunes hydrogen masers

Automatic tuning system permits frequency synchronization between two hydrogen masers. System matches spaceborne clock performance with that of ground-based clock to test red shift theory. This system, used in conjunction with radio astronomy for long-baseline interferometer experiments, serves as a tool for investigation of distant universe phenomena.

Levine, M. W.↗
NASA NTRS1984

The Boot Lake MF imaging radar

The Middle-Atmosphere Imaging Radar is located at the Boot Lake field site, 10 miles east of Brighton, Colorado. It operates at 2.66 MHz with a 50-kW peak pulse power in 30 microsecond pulses. Ten independent coaxial-collinear antennas are used; five are parallel and run east-west, the other five are parallel and run north-south. Each antenna consists of eight half-wave dipoles. All ten antennas or a crossed pair may be used for transmission; all ten are sampled by pairs in rapid sequence for reception. The system is now operating on a campaign basis as a Fourier interferometer by measuring the complex voltages on the ten antennas and Fourier transforming them independently. Multiple scatterers within a single range gate, now sorted by velocity, can be located individually by their phase angles. The transmitted signal cycles through four modes (N-S linear, right-hand circular, E-W linear, and left-hand circular).

Adams, G. W.↗
NASA NTRS1992

Space micro-guidance and control - Applications and architectures

The features and the components of a new microscale guidance, navigation, and control (GN&C) system for future space systems are discussed. An approach is described for the utilization of new microengineering technologies for achieving major reductions in the GN&C system's mass, size, power, and costs. The micro-GN&C system and the component concepts include microactuated adaptive optics, micromachined inertial sensors, fiberoptic data nets with light-power transmission, and VLSI microcomputers. The GN&C system will be applied in microspacecraft, microlanders, microrovers, remote sensing platforms, interferometers, and deployable reflectors.

Mettler, Edward↗
NASA NTRS2003

The Beauty and Limitations of 10 Micron Heterodyne Interferometry (ISI)

Until recently, heterodyne interferometry at 10 microns has been the only successful technique for stellar interferometry in the very difficult atmospheric window from 9-12 microns. For most of its operational lifetime the U.C. Berkeley Infrared Spatial Interferometer was a single-baseline two telescope (1.65 m aperture) system using CO2 lasers as local oscillators. This instrument was designed and constructed from 1983-1988, and first fringes were obtained at Mt. Wilson in June 1988. During the past few years, a third telescope was constructed and just recently the first closure phases were obtained at 11.15 microns. We discuss the history, physics and technology of heterodyne interferometry in the mid-infrared, and some key astronomical results that have come from this unique instrument.

Danchi, William C.↗
NASA NTRS1995

Observations of chemical processing in the circumstellar environment

High resolution interferometer and single-dish observations of young, deeply embedded stellar systems reveal a complex chemistry in the circumstellar environments of low to intermediate mass stars. Depletions of gas-phase molecules, grain mantle evaporation, and shock interactions actively drive chemical processes in different regions around young stars. We present results for two systems, IRAS 05338-0624 and NCG 1333 IRAS 4, to illustrate the behavior found and to examine the physical processes at work.

NASA Program Exobiology↗
NASA NTRS2012

Developing Wide-Field Spatio-Spectral Interferometry for Far-Infrared Space Applications

Interferometry is an affordable way to bring the benefits of high resolution to space far-IR astrophysics. We summarize an ongoing effort to develop and learn the practical limitations of an interferometric technique that will enable the acquisition of high-resolution far-IR integral field spectroscopic data with a single instrument in a future space-based interferometer. This technique was central to the Space Infrared Interferometric Telescope (SPIRIT) and Submillimeter Probe of the Evolution of Cosmic Structure (SPECS) space mission design concepts, and it will first be used on the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). Our experimental approach combines data from a laboratory optical interferometer (the Wide-field Imaging Interferometry Testbed, WIIT), computational optical system modeling, and spatio-spectral synthesis algorithm development. We summarize recent experimental results and future plans.

Leisawitz, David↗
NASA NTRS2018

Direct Probe of Dark Energy Interactions with a Solar System Laboratory: NASA Innovative Advanced Concepts (NIAC) - Phase 1 Final Report

In this NIAC (NASA Innovative Advanced Concepts) study, we embrace the challenge of direct detection of the galileon dark energy field in the Vainshtein model. We developed a mission concept to directly measure the galileon field using the solar system as a laboratory. The experiment scheme involves precise measurements of the trace of the total scalar force gradient tensor. A tetrahedral constellation off our spacecraft measures the "local" traces while orbiting about 1 AU (Astronomical Unit) away from the Sun and faraway from planets (Figure 1). The trace measurement is insensitive to the much stronger gravity field which satisfies the inverse square law and thus is traceless. Atomic test masses and atom interferometer measurement techniques are used as precise drag-free inertial references while laser ranging interferometers are employed to connect among atom interferometer pairs in spacecraft for the differential gradient force measurements. We conclude that such a mission is scientifically and technologically feasible. We show that a mission of 3-year measurement time would be able to provide high confidence statements (over 3 standard deviations) about the existence and strength of the cubic galileon field of the Sun. In addition, such a mission would also provide rich and diverse scientific data for testing any gravitational theory in general beyond the Newtonian gravity, hunting for ultra-light fields of dark matter, and detecting gravitational waves in the mid-frequency band between those of LIGO (Laser Interferometer Gravitational-Wave Observatory) and LISA (Laser Interferometer Space Antenna). For these reasons, we will term the mission concept Gravity Observation and Dark energy Detection Explorer in the Solar System (GODDESS).

Dark Energy↗
NASA NTRS2004

Kite: Status of the External Metrology Testbed for SIM

Kite is a system level testbed for the External Metrology system of the Space Interferometry Mission (SIM). The External Metrology System is used to track the fiducial that are located at the centers of the interferometer's siderostats. The relative changes in their positions needs to be tracked to tens of picometers in order to correct for thermal measurements, the Kite testbed was build to test both the metrology gauges and out ability to optically model the system at these levels. The Kite testbed is an over-constraint system where 6 lengths are measured, but only 5 are needed to determine the system. The agreement in the over-constrained length needs to be on the order of 140 pm for the SIM Wide-Angle observing scenario and 8 pm for the Narrow-Angle observing scenario. We demonstrate that we have met the Wide-Angle goal with our current setup. For the Narrow-Angle case, we have only reached the goal for on-axis observations. We describe the testbed improvements that have been made since our initial results, and outline the future Kite changes that will add further effects that SIM faces in order to make the testbed more SIM like.

metrology↗
NASA NTRS1993

CUPRI system configuration for NLC-91 and observations of PMSE during Salvo A

The Cornell University Portable Radar Interferometer (CUPRI) provided nearly continuous monitoring of the mesosphere above Esrange, Sweden during the noctilucent cloud rocket and radar campaign of the summer of 1991 (NLC-91). CUPRI probed the mesosphere above Esrange from 78 to 91 km altitude with 300-meter resolution and was sensitive to the enhanced Polar Mesospheric Summer Echoes (PMSE) that occur in the same altitude range as NLC formations. Out of the total of 264 hours of CUPRI observation time, PMSE were present for 140 hours. Rocket Salvo A was flown on the night of August 9-10 into an NLC event that occurred simultaneously with a thin and weakening PMSE layer. High-resolution Doppler spectrograms of this PMSE event revealed sawtooth-like discontinuities at approximately 83 km altitude, which we interpret to be a distorted partial reflection layer which was advected across the radar beam.

Swartz, Wesley E.↗
NASA NTRS2010

Systems Engineering and Application of System Performance Modeling in SIM Lite Mission

The SIM Lite Astrometric Observatory will be the first space-based Michelson interferometer operating in the visible wavelength, with the ability to perform ultra-high precision astrometric measurements on distant celestial objects. SIM Lite data will address in a fundamental way questions such as characterization of Earth-mass planets around nearby stars. To accomplish these goals it is necessary to rely on a model-based systems engineering approach - much more so than most other space missions. This paper will describe in further detail the components of this end-to-end performance model, called "SIM-sim", and show how it has helped the systems engineering process.

Exoplanet↗
NASA NTRS1988

Meteorological satellite products support for project COHMEX

The first year effort focussed on real-time support and satellite data collection during the field phase of COHMEX. Work efforts following the field phase of COHMEX concentrated on post-processing of the real-time data sets, and generation of enhanced, research-quality satellite data sets for selected COHMEX core days. These satellite-derived data sets will augment the special COHMEX conventional data base with high horizontal and temporal resolution information. The data sets will be examined for their usefulness in delineating important elements in the meteorological environment leading to convective activity. In addition, a limited research effort was conducted using the Cooperative Institute for Meteorological Satellite Studies (CIMSS) 4-d data assimilation system in conjunction with evaluating VISSR Atmospheric Sounder (VAS) and His-resolution Interferometer Sounder (HIS) data. The need to address the characteristics of the data types, and the problems they introduce into 4-d assimilation procedures is evident. The HIS instrument was flown aboard an ER-2 aircraft on several occasions during COHMEX. One of the flights was chosen for further study. Processed VAS soundings and COHMEX radiosonde data were also collected for this day. The case study included an evaluation of the HIS and VAS data and an impact study of the data on the assimilation system analysis.

Velden, Christopher S.↗
NASA NTRS1990

Comparisons of SiO maser and long-period variable positions in the R Aquarii and Omicron Ceti binary systems

It has been determined that the absolute position of the centroid of SiO maser-emitting spots toward both R Aqr and Omicron Cet are coincident with the position of the long-period variables (LPVs) in these binary systems to within the errors of measurement. The SiO positions were determined with the Hat Creek interferometer, while the LPV positions were determined with the 8-in transit circle of the US Naval Observatory. These results contradict an earlier report of a circumbinary SiO maser far removed from the LPV in the R Aqr binary system; statistical reasons for the discrepancy are suggested. High-resolution spectra of both sources are presented and possible models are discussed.

Hollis, J. M.↗
NASA NTRS2003

Optical path control in the MAM testbed

Future space-based optical interferometers will require control of the optical path delay to accomplish some or all of the three objectives: balancing the optical path in the two arms to within a tolerance corresponding to the coherence length of the star light being observed, modulating the optical path in order to observe the phase of the star light interference fringe, and modulating the path length in order to reduce the effect of cyclic errors in the laser metrology system used to measure the optical path length in the two arms of the interferometer.

optical interferometers optical path MAM testbed M↗
NASA NTRS2003

Aligning Three Off-Axis Mirrors with Help of a DOE

A proposed method based on the use of a special-purpose diffractive optical element (DOE) would simplify (relative to prior methods) the alignment of three off-axis mirrors that constitute an imaging optical system. The method would exploit the fact that a DOE can be fabricated lithographically with high accuracy by electron-beam lithography in a thin film of poly(methyl methacrylate). The method would effectively transfer much of the problem of obtaining the needed accuracy from the mechanical-mirror-alignment domain to the lithographic domain. Unlike other methods that depend on specific symmetries (e.g., sphericity and/or concentricity), this method is expected to apply with equal ease and accuracy to mirrors of any configuration including aspherical, decentered mirrors. Assuming that one of the mirrors of a general three-mirror imaging optical system can serve as a reference for the alignment of the other two mirrors, such a system has 12 degrees of freedom in alignment. In the proposed method, one would use an interferometer in combination with a DOE to effect precise and relatively rapid and easy alignment of two of the mirrors with respect to each other, thus reducing the alignment task to that of the six degrees of freedom of the remaining mirror. The figure depicts a representative three-mirror off-axis imaging system, wherein the primary and tertiary mirrors (M1 and M3, respectively) are concave and the secondary mirror (M2) is convex. The DOE for aligning this system would be fabricated on the right surface of an optical flat and could be made to have either negative or positive focusing power, depending on the requirements of the specific application. The DOE could be designed to be placed at any convenient distance from M1 and M3 - again, depending on the application. The DOE would be illuminated with light coming from the left, generated by an interferometer. First, assuming the optical flat is of high quality, the plane of the DOE would be aligned perpendicular to the collimated beam by use of light reflected from the left face of the optical flat. The DOE would comprise two independent areas: one dedicated to M1, the other to M3. The portions of the collimated beam passing through those areas would be diffracted towards the corresponding mirrors. A mask, not shown in the figure, could be used to prevent light from passing through the rest of the area of the optical flat. Light rays reflected from M1 and M3 would retrace their paths through the DOE and would propagate leftward to the interferometer.

Mouroulis, Pantazis↗