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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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This paper describes some of the software engineering practices that are being used by the Realtime Interferometer Control Systems Testbed (RICST) project at JPL to address integration and integratability issues.
Must perform functional and environment tests. Must evaluate in end-to-end interferometer testbeds to verify functional performance. Re-engineer based on test results. More complete design qualification design and test.
This paper describes key features of the instrument, spacecraft, and mission design for the Precision Optical INTerferometer in Space (POINTS), which have evolved through studies at the Jet Propulsion Laboratory during the last few years. This paper complements others in theis volume that describe the POINTS instrument, its scientific objectives, and specific engineering concerns.
Teh NASA/JPL TOPSAR instrument recently was extended from a single wavelength C-band dual aperture synthetic aperture radar interferometer to include a second wavelength at L-band. Adding the second wavelength invites comparison of wavelength diverse effects in topographic mapping of surfaces, with the principal goal of understanding the penetration of the radar signals in vegetation canopies, and determining the inferred topographic height.
In this paper we will describe recent advances in the development of optical systems for future space infrared telescope and interferometer applications which will operate at very low or cryogenic temperatures (T less then or equal to 77K) with emphasis on beryllium and silicon carbide optics.
This paper validates the integrated modeling methodology used for design and performance evaluation of complex opto-mechanical systems, particularly spaceborne interferometers. The methodology integrates structural modeling, optical modeling, and control system design into a common environment, the Integrated Modeling of Optical Systems (IMOS) software package.
This paper validates the integrated modeling methodology used for design and performance evaluation of complex opto-mechanical systems, particularly spaceborne interferometers.
This paper describes the technical program that will demonstrate the viability of two mid-infrared interferometer architectures being developed for the Terrestrial Planet Finder (TPF) to support a mission concept downselect in 2006.
The Jet Propulsion Laboratory is developing a 512x640-format, dual broadband, Quantum Well Infrared Photodetector (QWIP) focal plane array (FPA for an imaging interferometer.
This paper presents a validation study of a specific integrated modeling methodology which is a candidate tool for modeling complex opto-mechanical systems such as spaceborne interferometers.
We present results from a time-energy entanglement Bell inequality violation measurement of two highly non-degenerate photons using a compact Franson interferometer. The entangled photons are generated via the spontaneous parametric downconversion of a 532 nm pump photon into time-energy and polarization degrees of freedom hyper-entangled 810 nm and 1550 nm photons. The source is a type II periodically poled potassium titanyl phosphate (KTP) crystal with a fiber-coupled input and free-space output. These wavelengths are of particular interest as they lie at the intersection of free-space quantum communication and terrestrial entanglement distribution due to 810 nm undergoing little atmospheric absorption, making it a candidate for satellite to ground quantum links. Furthermore, 1550 nm is capable of directly interfacing with existing telecommunications infrastructure. We report an initial violation of Bell's inequality by more than 3 standard deviations and describe efforts to improve upon this while maintaining stable operation in a low size, weight, and power (SWaP) package.
We present the status of the atomic interferometer gravity gradiometer (AIGG) instrument in development at NASA GSFC, along with the simulated science performance for a variety of potential implementation scenarios. These trade studies include assessing mission performance for varying levels of AIGG instrument sensitivity, different orientations of the single-axis AIGG, and different satellite altitudes. Additionally, we quantify performance for both single-platform AIGG-only and combined satellite-to-satellite (SST) and AIGG observing systems. An important part of this work is the determination of the AIGG instrument sensitivity threshold required to enhance the mass change measurements beyond the SST-only performance. The simulated AIGG science performance is compared to various single and dual-pair Bender constellations and the Science and Applications Traceability Matrix that resulted from NASA’s Mass Change Designated Observable study.
The National Airborne Sounder Testbed-Interferometer (NAST-I) is an existing ultraspectral infrared sounder flown on high-altitude aircraft that provides high spectral and spatial resolution measurements which continue to advance understanding of science critical for weather, climate, chemistry, and radiation applications. NAST-I provides high-spatial linear resolution equal to 13% of the aircraft altitude at nadir (i.e., 2.6 km IFOV on the ground from an aircraft altitude of 20 km), and high-spectral resolution (0.25 cm -1 ) measurements within the spectral region of 645–2700 cm -1 . The NAST-I suborbital system serves as a spaceborne instrument simulator and pathfinder for future satellite capabilities and airborne science experiments. Here we present some groundbreaking capabilities of NAST-I measurements and corresponding geophysical retrievals and their potential benefits toward improved atmospheric state and composition characterizations needed for air quality, wildfire, and other science applications.
An absorption laser differential interferometer (A-LDI) system can be used to provide simultaneous, colinear measurements of flow properties (pressure, temperature, concentration, velocity) and flow fluctuations. Further characterization work on the absorption aspect of the system is provided in this paper, including characterization of the laser operating parameters, comparisons of two etalons of different free spectral range, and the further evaluation of a fixed-wavelength absorption measurement that can be used to obtain absorption and LDI measurements with the same sampling rate. A 0.4 GHz etalon was demonstrated to provide sufficient fringe peaks at low modulation depths to be used for the low-pressure testing characteristic of hypersonic wind tunnel facilities. The use of a 3 GHz etalon as a low-cost relative wavemeter was tested and validated. Data taken with the fixed-wavelength strategy in a sub-atmospheric test cell using 100% O2was successful and will allow absorption and LDI data to be acquired simultaneously, colinearly, and at the same sampling rate, yielding a truly simultaneous measurement of the flow density fluctuations and the flow mean density.
An absorption laser differential interferometer (A-LDI) system can be used to provide simultaneous, colinear measurements of flow properties (pressure, temperature, concentration, velocity) and flow fluctuations. Further characterization work on the absorption aspect of the system is provided in this paper, including characterization of the laser operating parameters, comparisons of two etalons of different free spectral range, and the further evaluation of a fixed-wavelength absorption measurement that can be used to obtain absorption and LDI measurements with the same sampling rate. A 0.4 GHz etalon was demonstrated to provide sufficient fringe peaks at low modulation depths to be used for the low-pressure testing characteristic of hypersonic wind tunnel facilities. The use of a 3 GHz etalon as a low-cost relative wavemeter was tested and validated. Data taken with the fixed-wavelength strategy in a sub-atmospheric test cell using 100% O 2 was successful and will allow absorption and LDI data to be acquired simultaneously, colinearly, and at the same sampling rate, yielding a truly simultaneous measurement of the flow density fluctuations and the flow mean density.
The National Airborne Sounder Testbed-Interferometer (NAST-I) is an existing ultraspectral infrared sounder flown on high-altitude aircraft that provides high spectral and spatial resolution measurements which continue to advance understanding of science critical for weather, climate, chemistry, and radiation applications. NAST-I provides high-spatial linear resolution equal to 13% of the aircraft altitude at nadir (i.e., 2.6 km IFOV on the ground from an aircraft altitude of 20 km), and high-spectral resolution (0.25 cm-1) measurements within the spectral region of 645–2700 cm-1. The NAST-I suborbital system serves as a spaceborne instrument simulator and pathfinder for future satellite capabilities and airborne science experiments. Present herein are some groundbreaking capabilities of NAST-I measurements and corresponding geophysical retrievals and their potential benefits toward improved atmospheric state and composition characterizations needed for air quality, wildfire, and other science applications and, in particular, for enhanced Planetary Boundary Layer (PBL) characterization and understanding.
Context. Following the recommendations to NASA (in the Astro2020 Decadal survey) and ESA (through the Voyage2050 process), the search for life on exoplanets will be a priority in the next decades. Two concepts for direct imaging space missions are being developed for this purpose: the Habitable Worlds Observatory (HWO) and the Large Interferometer for Exoplanets (LIFE). These two concepts operate in different spectral regimes: HWO is focused on reflected light spectra in the ultraviolet, visible, and near-infrared (UV/VIS/NIR), while LIFE will operate in the mid-infrared (MIR) to capture the thermal emission of temperate exoplanets. Aims. In this study, we aim to assess the potential of HWO and LIFE to characterize a cloud-free Earth twin orbiting a Sun-like star at a distance of 10 pc, both as separate missions and in synergy with each other. We aim to quantify the increase in information that can be gathered by joint atmospheric retrievals on a habitable planet. Methods. We performed Bayesian retrievals on simulated data obtained by an HWO-like mission and a LIFE-like one separately, then jointly. We considered the baseline spectral resolutions currently assumed for these concepts and used two increasingly complex noise simulations, obtained using state-of-the-art noise simulators. Results. An HWO-like concept would allow one to strongly constrain H 2 O, O 2 , and O 3 in the atmosphere of a cloud-free Earth twin, while the atmospheric temperature profile is not well constrained (with an average uncertainty ≈100 K). LIFE-like observations would strongly constrain CO 2 , H 2 O, and O 3 and provide stronger constraints on the thermal atmospheric structure and surface temperature (down to ≈10 K uncertainty). For all the investigated scenarios, both missions would provide an upper limit on CH 4 . A joint retrieval on HWO and LIFE data would accurately define the atmospheric thermal profile and planetary parameters. It would decisively constrain CO 2 , H 2 O, O 2 , and O 3 and find weak constraints on CO and CH 4 . The significance of the detection is in all cases greater than or equal to the single-instrument retrievals. Conclusions. Both missions provide specific information that is relevant for the characterization of a terrestrial habitable exoplanet, but the scientific yield can be maximized by considering synergistic studies of UV/VIS/NIR+MIR observations. The use of HWO and LIFE together will provide stronger constraints on biosignatures and life indicators, with the potential to be transformative for the search for life in the Universe.
An inertial sensing system includes a magneto-optical trap (MOT) that traps atoms within a specified trapping region. The system also includes a cooling laser that cools the trapped atoms so that the atoms remain within the specified region for a specified amount of time. The system further includes a light-pulse atom interferometer (LPAI) that performs an interferometric interrogation of the atoms to determine phase changes in the atoms. The system includes a controller that controls the timing of MOT and cooling laser operations, and controls the timing of interferometric operations to substantially recapture the atoms in the specified trapping region. The system includes a processor that determines the amount inertial movement of the inertial sensing system based on the determined phase changes in the atoms. Also, a method of inertial sensing using this inertial sensing system includes recapture of atoms within the MOT following interferometric interrogation by the LPAI.