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NASA NTRS2025

Limitations and Feasibility of Mini X-Ray Devices in Space Environments

LIMITATIONS AND FEASIBILITY OF MINI X-RAY DEVICES IN SPACE ENVIRONMENTS As space exploration advances toward long-duration missions, reliable medical diagnostic tools become increasingly critical. The miniature x-ray (XR) technology demonstrations by the Exploration Medical Capability (ExMC) and the Exploration Medical Integrated Product Team (XMIPT) aim to assess the feasibility and utility of miniature XR devices in spaceflight. This abstract explores the limitations of current miniature XR systems, the challenges of training crew members, the potential role of clinical decision support systems (CDSS), and the feasibility of ground-based image interpretation. We also propose the integration of miniature XR into other ExMC efforts aimed at identifying the capabilities and resources needed for future exploration class missions. One of the primary challenges with miniature XR devices is the ability to achieve specific anatomical views, particularly in the confined and weightless conditions of a spacecraft. Operators may struggle to acquire diagnostic-quality images when space is limited for proper patient positioning and the volume of the imaging device. Since space radiation and detector limitations may further impact image quality, the flexibility of the operating procedures of these devices will be critical for their success in space applications. CHALLENGES IN TRAINING CREW TO OPERATE IMAGING DEVICES Training in the skills necessary to acquire diagnostic-quality scans may be a barrier for non-clinician crewmembers. The curriculum developed for crew medical officers (CMOs) will require simplification and adaptation to fit into the highly truncated pre-flight training period. Therefore, hands-on familiarization and simulation, both pre-flight and just-in-time training during missions, will be crucial to ensuring the crew can operate the devices in real-life situations. The ability to adjust acquisition parameters must be simplified or made automatic through exam selections on equipment user interfaces, and subject and operator positioning should be assisted with laser guidance and pictorial guides. POTENTIAL FOR CDSS OR ARTIFICIAL INTELLIGENCE (AI)-ASSISTED CDSS CDSS and AI-assisted CDSS offer significant promise in assisting crew members with limited medical training. These systems could provide real-time feedback on image quality and interpretation, helping to mitigate the risks of human error during space missions. Integrating procedural guidance tools, such as virtual and augmented reality, will support crewmembers in accurately positioning patients and obtaining high-quality images. However, the success of such systems will depend on the development of robust training datasets, integration with spaceflight-rated hardware, and the medical decision-making capabilities of operators. FEASIBILITY OF GROUND INTERPRETATION AND DATA TRANSMISSION Reliance on ground-based interpretation may prove difficult for acute care during exploration class-missions due to delays in transmission with increasing distance from Earth or complete communication blackout periods. In such instances where immediate interpretation for clinical intervention is required, crew must be able to interpret the images independently or utilize AI-based assistance to do so. File sizes for XR exams can also be large if numerous images are acquired and bandwidth constraints may limit data transmissions for both radiography and ultrasound exams. FUTURE WORK AND INTEGRATION INTO THE EVIDENCE LIBRARY Future work proposes integrating miniature XR devices into NASA’s Evidence Library to address medical conditions identified as significant contributors to crew morbidity and mortality. The possibility of combining miniature XR with other imaging modalities, such as ultrasound devices, is also under investigation. In conclusion, while miniature XR technology holds potential for extraterrestrial medical systems, there are significant challenges to overcome. Training, integration of AI tools, dedicated exam protocols for microgravity, and improved data transmission systems will be key to realizing the full benefits of miniature XR technology in space.

A M Nelson↗

NASA NTRS1972

Infrared thermal mapping experiment - The Viking Mars Orbiter.

The Mars infrared thermal mapper (IRTM) will be carried on the scan platform of the orbiter of the Viking 1975 mission. The IRTM is a multichannel radiometer with several detectors in each of six spectral regions. The spectral channels are selected to be sensitive to surface emissivity variations and provide good temperature resolution over the entire range of Martian temperatures. These observations will allow determination of the surface kinetic temperature and thermal balance, and by coverage of the dark hemisphere, a search for regions with anomalous cooling can be made. Observations of ground frosts or clouds will help to determine their composition, and in the case of extensive H2O frosts, will allow the local water vapor pressure to be estimated.

Kieffer, H. H.↗

NASA NTRS2000

JSC Stardust Curation Team

STARDUST, a NASA Discovery-class mission, is the first to return samples from a comet. Grains from comet Wild 2's coma-the gas and dust envelope that surrounds the nucleus-will be collected as well as interstellar dust. The mission which launched on February 7, 1999 will encounter the comet on January 10, 2004. As the spacecraft passes through the coma, a tray of silica aerogel will be exposed, and coma grains will impact there and become captured. Following the collection, the aerogel tray is closed for return to Earth in 2006. A dust impact mass spectrometer on board the STARDUST spacecraft will be used to gather spectra. of dust during the entire mission, including the coma passage. This instrument will be the best chance to obtain data on volatile grains, which will not be well-collected in the aerogel. The dust impact mass spectrometer will also be used to study the composition of interstellar grains. In the past 5 years, analysis of data from dust detectors aboard the Ulysses and Galileo spacecraft have revealed that there is a stream of interstellar dust flowing through our solar system. These grains will be captured during the cruise phase of the STARDUST mission, as the spacecraft travels toward the comet. The sample return capsule will parachute to Earth in February 2006, and will land in western Utah. Once on y the ground, the sample return capsule will be placed into a dry nitrogen environment and flown to the curation lab at JSC.

Zolensky, Michael E.↗

NASA NTRS2015

Optical Parametric Technology for Methane Measurements

Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas, with approximately 25 times the radiative forcing of carbon dioxide (CO2) per molecule. Yet, lack of understanding of the processes that control CH4 sources and sinks and its potential release from stored carbon reservoirs contributes significant uncertainty to our knowledge of the interaction between carbon cycle and climate change. At Goddard Space Flight Center (GSFC) we have been developing the technology needed to remotely measure CH4 from orbit. Our concept for a CH4 lidar is a nadir viewing instrument that uses the strong laser echoes from the Earth's surface to measure CH4. The instrument uses a tunable, narrow-frequency light source and photon-sensitive detector to make continuous measurements from orbit, in sunlight and darkness, at all latitudes and can be relatively immune to errors introduced by scattering from clouds and aerosols. Our measurement technique uses Integrated Path Differential Absorption (IPDA), which measures the absorption of laser pulses by a trace gas when tuned to a wavelength coincident with an absorption line. We have already demonstrated ground-based and airborne CH4 detection using Optical Parametric Amplifiers (OPA) at 1651 nm using a laser with approximately 10 microJ/pulse at 5kHz with a narrow linewidth. Next, we will upgrade our OPO system to add several more wavelengths in preparation for our September 2015 airborne campaign, and expect that these upgrades will enable CH4 measurements with 1% precision (10-20 ppb).

oscillator↗

NASA NTRS1976

Breadboard linear array scan imager using LSI solid-state technology

The performance of large scale integration photodiode arrays in a linear array scan (pushbroom) breadboard was evaluated for application to multispectral remote sensing of the earth's resources. The technical approach, implementation, and test results of the program are described. Several self scanned linear array visible photodetector focal plane arrays were fabricated and evaluated in an optical bench configuration. A 1728-detector array operating in four bands (0.5 - 1.1 micrometer) was evaluated for noise, spectral response, dynamic range, crosstalk, MTF, noise equivalent irradiance, linearity, and image quality. Other results include image artifact data, temporal characteristics, radiometric accuracy, calibration experience, chip alignment, and array fabrication experience. Special studies and experimentation were included in long array fabrication and real-time image processing for low-cost ground stations, including the use of computer image processing. High quality images were produced and all objectives of the program were attained.

Tracy, R. A.↗

NASA NTRS1985

An Analysis of the High Frequency Vibrations in Early Thematic Mapper Scenes

The motion of the mirrors in the thematic mapper (TM) and multispectral scanner (MSS) instruments, and the motion of other devices, such as the TDRSS antenna drive, and solar array drives onboard LANDSAT-4 cause vibrations to propagate through the spacecraft. These vibrations as well as nonlinearities in the scanning motion of the TM mirror can cause the TM detectors to point away from their nominal positions. Two computer programs, JITTER and SCDFT, were developed as part of the LANDSAT-D Assessment System (LAS), Products and Procedures Analysis (PAPA) program to evaluate the potential effect of high frequency vibrations on the final TM image. The maximum overlap and underlap which were observed for early TM scenes are well within specifications for the ground processing system. The cross scan and scan high frequency vibrations are also within the specifications cited for the flight system.

Kogut, J.↗

NASA NTRS1988

Development of the SAMEX vector magnetograph at the Marshall Space Flight Center

A breadboard design to prove the operational feasibility of SAMEX Vector Magnetograph is being developed. Although the breadboard design will not include all of the elements of the original design concept, critical elements such as the large detector array and the high resolution polarimeter will be important parts of the breadboard design to study the data analysis and compression techniques that will be needed in a SAMEX instrument, to study the calibration techniques for systemmatic errors in the polarimeter, and to obtain high resolution vector magnetograms during the next solar maximum. Although the SAMEX polarimeter is not optimum for a ground-based patrol instrument, the design concept can be confirmed with ground-based measurements and direct comparisons with the existing vector magnetograph. The extension of the scientific objectives for this breadboard design is possible if a tunable filter can be acquired.

West, E. A.↗

NASA NTRS2007

A Hard-X-Ray Telescope Science Enhancement Package for the Constellation-X Mission

We present a science enhancement package (SEP) for NASA's planned Constellation-X mission submitted in response to a call for white papers. The call solicited proposals for either extending the bandwidth of Con-X to higher energies or enhancing the low-energy spectral resolution. The ground rules were that enhancement package should cost no more than $100M and weigh no more than 100 kg. The nickel-replicated-optics team responded with a stand-alone hard-x-ray telescope SEP concept. This consisted of two mirror modules, each with approximately 70 multilayer and iridium-coated shells, and two corresponding cadmium-zinc-telluride-based focal plane detectors. Addition of this package permits measurement of the hard-x-ray continuum up to 30-40 keV, which is essential for a quantitative measurement of the spectrum of gravitationally broadened iron lines that appear in the spectra of many black hole candidates. Full details of the instrument will be presented showing trades in energy bandwidth and effective area together with the full science justification for the enhancement package.

Ramsey, Brian↗

NASA NTRS2003

Detecting Conductive Liquid Leaking from Nonconductive Pipe

A method that can be implemented with relatively simple electronic circuitry provides a capability for detecting leakage of an electrically conductive liquid from an electrically nonconductive underground pipe. Alternatively or in addition, the method can be applied to locate the pipe, whether or not there is a leak. Although the method is subject to limitations (some of which are described below), it is still attractive as an additional option for detecting leaks and locating pipes without need for extensive digging. The method is based on capacitive coupling of an alternating electrical signal from the liquid to a portable electronic unit that resembles a metal detector. A signal voltage is applied to the liquid at some convenient point along the pipe: for example, the signal could be coupled into the liquid via an aboveground metal pipe fitting, the interior surface of which is in contact with the liquid. The signal is conducted through the liquid in the pipe; in the case of diffusive leak of liquid into the surrounding ground, the signal is conducted through the leak, into the portion of the adjacent ground that has become soaked with the liquid. (A drip leak cannot be detected by this method because there is no conductive path between the liquid inside and the liquid outside the pipe.) The portable unit includes an electrically conductive plate connected to the input terminal of an amplifier. When the plate is brought near the pipe or the leaked liquid, a small portion of the signal power is coupled capacitively from the liquid to the plate. The user scans the plate near the ground surface to find the locus of maximum signal strength. The leak can be identified as a relatively wide area, contiguous with the location of the pipe, over which the signal is detectable.

Youngquist, Robert C.↗

DOE OSTI2025

One-shot gas detection with transformer paired neural networks in Mako collected longwave infrared hyperspectral imagery

To date, careful data treatment workflows and statistical detectors are used to perform hyperspectral image (HSI) detection of any gas contained in a spectral library, which is often expanded with physics models to incorporate different spectral characteristics. In general, surrounding evidence or known gas-release parameters are used to provide confidence in or confirm detection capability, respectively. This makes quantifying detection performance difficult as it is nearly impossible to develop an absolute ground truth for gas target pixel presence in collected HSI. Consequently, developing and comparing new detection methods, especially machine learning (ML)-based methods, is susceptible to subjectivity in derived detection map quality. Here, in this work, we demonstrate the first use of transformer-based paired neural networks (PNNs) for one-shot gas target detection for multiple gases while providing quantitative classification and detection metrics for their use on labeled data. Terabytes of training data are generated from a database of long-wave infrared HSI obtained from historical Mako sensor campaigns over Los Angeles. By incorporating labels, singular signature representations, and a model development pipeline, we can tune and select PNNs to detect multiple gas targets that are not seen in training on a quantitative basis. We additionally assess our test set detections using interpretability techniques widely employed with ML-based predictors, but less common with detection methods relying on learned latent spaces.

Hyperspectral imaging↗

NASA NTRS1978

Performance analysis of a filtered wide field-of-view radiometer for earth radiation budget measurements

The proposed Earth Radiation Budget Satellite System (ERBSS) of the 1980's will include a wide field-of-view (WFOV) fixed axes earth radiator discriminator consisting of a shortwave channel and a total (unfiltered) channel. The broadband spectral isolation required for the shortwave channel is achieved by use of a hemispherical fused silica (Suprasil W) dome filter placed in front of a wire wound thermopile radiation detector. A description is presented of the thermal response of the single-fused silica dome filter in the ERBSS WFOV shortwave channel conceptual design and the impact of that response on the channel measurement. Results from design definition and performance analysis studies are included. Problems associated with achieving the desired levels of confidence in a high accuracy filtered, WFOV radiometer are discussed. Design approaches, ground calibration, and data reduction techniques which minimize measurement uncertainties are explained.

Cooper, J. E.↗

NASA NTRS1981

Observations of the plasma torus of Jupiter with a Fabry-Perot/charge-coupled device /CCD/ imaging spectrometer

A description is presented of the use of a CCD imaging spectrometer which has been employed at a 2.1 m telescope to obtain monochromatic images in the red and near infrared. The system studied was Jupiter's plasma torus which circles the planet with radial extent about 5 RJ and 7 RJ (RJ is the radius of Jupiter). In ground based measurements the torus has been observed in the forbidden emission lines of S(plus) at 6716 A and 6731 A and S(plus plus) at 9531 A. Attention is given to aspects of instrumentation, observations, and performance. It is felt that the particular significance of the obtained results from the instrumental point of view is the demonstration that the CCD is an excellent detector for monochromatic imaging in the near infrared out to at least 10830 A and that pixel binning before readout can produce significantly improved S/N ratios for the study of faint, diffuse sources in cases where readout noise is dominant.

Roesler, F. L.↗

NASA NTRS1986

Astrometric telescope of ten microarcsecond accuracy on the Space Station

The Astrometric Telescope Facility (ATF) will be operated in the NASA Space Station in the 1990s, furnishing long term, highly accurate relative astrometry of nearby stars in order to detect gravitational perturbations by companion stars with masses as small as that of Neptune. An accuracy of 10 microarcsec is required; this is 100 times better than ground observatory performance. In the Gatewood et al. (1980) astrometric technique used, the relative positions of star images in the telescope focal plane are indicated by the relative phases of the modulations of star brightnesses introduced by translating a Ronchi ruling across the focal plane at uniform speed. Space Station vibration damping, fine guiding accuracy, optical configuration, Ronchi ruling metric accuracy, and the choice of detectors, are discussed.

Levy, E. H.↗

NASA NTRS1993

The HYDICE instrument design and its application to planetary instruments

The Hyperspectral Digital Imagery Collection Experiment (HYDICE) instrument represents a significant advance in the state of the art in hyperspectral sensors. It combines a higher signal-to-noise ratio (SNR) and significantly better spatial and spectral resolution and radio metric accuracy than systems flying on aircraft today. The need for 'clean' data, i.e., data free of sampling artifacts and excessive spatial or spectral noise, is a key driver behind the difficult combination of performance requirements laid out for HYDICE. Most of these involve the sensor optics and detector. This paper presents an optimized approach to those requirements, one that comprises push broom scanning, a single, mechanically cooled focal plane, a double-pass prism spectrometer, and an easily fabricated yet wide-field telescope. Central to the approach is a detector array that covers the entire spectrum from 0.4 to 2.5 microns. Among the major benefits conferred by such a design are optical and mechanical simplicity, low polarization sensitivity, and coverage of the entire spectrum without suffering the spectral gaps caused by beam splitters. The overall system minimizes interfaces to the C-141 aircraft on which it will be flown, can be calibrated on the ground and in flight to accuracies better than those required, and is designed for simple, push-button operation. Only unprocessed data are recorded during flight. A ground data processing station provides quick-look, calibration correction, and archiving capabilities, with a throughput better than the requirements. Overall performance of the system is expected to provide the solid database required to evaluate the potential of hyperspectral imagery in a wide variety of applications. HYDICE can be regarded as a test bed for future planetary instruments. The ability to spectrally image a wide field of view over multiple spectral octaves offers obvious advantages and is expected to maximize science return for the required cost and weight.

Basedow, R.↗

NASA NTRS1998

Auroral Microphysics Rocket (AMICIST) and Reflight of the Phaze Sounding Rocket

This grant was originally awarded for the flight of the AMICIST sounding rocket. However, upon launch failure of the PHAZE rocket, additional resources were placed in this grant to cover the launch of the PHAZE II rocket. AMICIST was successfully launched from the Poker Flat Range on February 24, 1995, and the PHAZE II was successfully launched also from the Poker Flat Range on February 10, 1997. The major objective of the AMICIST flight was to investigate the bursts of transverse ion acceleration occurring during aurora, commonly known as Lower Hybrid Solitary Structures, with the flight of two scientific payloads to unravel space from time effects. The data clearly showed that the structures of ion acceleration were a spatial phenomena having a scale size transverse to the local magnetic field of about 100 m. On the other hand, structures in the auroral electrons were generally observed on this flight to be temporal features that occurred at the same time at the two payloads separated by a few kilometers. The primary objective of the PHAZE rocket flight was to further study the temporal features of auroral electron precipitation having many electron detectors, some fixed in energy, that could study the distribution function of the auroral electrons on time scales of a fraction of a millisecond. A important paper on this topic has just been submitted for publication which uses the PHAZE data to show that the potential structure (electric field parallel to the magnetic field) that accelerates the auroral electrons within one Earth radius of the ground, is not static, but rather fluctuates with frequencies close to the local proton and hydrogen gyrofrequencies. The fluctuation appears to be an actual turning on and off of the electric field at these frequencies. When the potential is turned off, ambient electrons can enter the region and be accelerated along B when the potential is on creating field- aligned bursts which manifest themselves as flickering aurora seen from the ground. The on/off model can explain many of the dynamic features of the aurora which have been unexplained since man first looked up at the visual display. Much needs to be done yet to understand how ions couple into this process.

Arnoldy Roger L.↗

NASA NTRS2019

IceSat 2 ATLAS Photon-Counting Receiver - Initial On-Orbit Performance

Photon-counting receivers are deployed on the NASA Ice, Cloud and land Elevation Satellite-2 (ICESat2) Advance Topographic Laser Altimeter System (ATLAS). The ATLAS laser altimeter design has total six ground tracks with three strong and three weak tracks. The strong track has nominally 4 times more laser power than the weak track. The receiver is operated in photon counting mode. There are 16 photon-counting channels for each strong track and 4 photon-counting channels for each weak track. Hamamatsu photomultiplier with a 4x4-array anode was used as photon counting detector. This receiver design has high counting efficiency (>15%) at 532 nm, low dark count rate (<400 counts per second), low jitter (less than 285ps), short dead time (<3 ns), long lifetime under large solar background radiation, radiation harden for space operation, and ruggedized for survives the harsh vibration during the launch. In this paper, we will present the initial on-orbit performance of this photon-counting receiver.

Yang, Guangning↗

NASA NTRS2020

Fitting Leak Test Report

Many Human Landing System flight elements are anticipated to implement mechanically connected joints in cryogenic fluid lines to simplify system assembly. These joints will need to survive launch vibration, while cold, and remain as leak‐free as possible to minimize commodity loss. Threaded fluid fittings should be qualified for use in their expected environments to reduce risk and ensure mission success. A new ground‐based test apparatus was developed and validated to obtain quantifiable low leak rate test data for a small component, such as a pressurized threaded fluid fitting, while in the temperature range of liquid hydrogen. A cryocooler is used to attain the cold test temperature and helium leakage from a pressurized fitting mounted within a vacuum test chamber is measured using a mass spectrometer leak detector. Two different sizes of Swagelok VCR fittings with three different types of seal rings were selected as the test articles for the initial proof of concept testing. Each fitting configuration was subjected to two consecutive cryogenic thermal cycles and cold leak measurement tests, followed by exposure to a high vibration test profile at ambient temperature on a shaker table, and then two additional cold leak measurement tests. Very low leak rates, below the acceptable leak rate threshold, were measured at the pressures tested. Several enhancements to the test hardware are discussed that would facilitate a comprehensive fitting qualification test campaign by enabling a higher test throughput rate and ensuring a repeatable test profile.

Cryogenic Fluid Management↗

DOE OSTI2024

Machine learning based unfolding of x-ray spectra from filter stack spectrometer data

We demonstrate the application of neural networks to perform x-ray spectra unfolding from data collected by filter stack spectrometers. A filter stack spectrometer consists of a series of filter-detector pairs, where the detectors behind each filter measure the energy deposition through each layer as photo-stimulated luminescence (PSL). The network is trained on synthetic data, assuming x-rays of energies < 1 MeV and of two different distribution functions (Maxwellian and Gaussian) and the corresponding measured PSL values obtained from five different filter stack spectrometer designs. Predicted unfolds of single distributions are near identical reproductions of the ground truth spectra, with differences in the values lower than 20% at the higher energy end in some cases. The neural network has also demonstrated robustness to experimental measurement errors of < 5% and some capability of performing unfolds for linear combinations of the two distributions without previous training. The network can perform unfolds at rates > 1 Hz, ideal for application to some high-repetition-rate systems.

47 OTHER INSTRUMENTATION↗