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NASA NTRS2014

Reconstructing the Sky Location of Gravitational-Wave Detected Compact Binary Systems: Methodology for Testing and Comparison

The problem of reconstructing the sky position of compact binary coalescences detected via gravitational waves is a central one for future observations with the ground-based network of gravitational-wave laser interferometers, such as Advanced LIGO and Advanced Virgo. Different techniques for sky localization have been independently developed. They can be divided in two broad categories: fully coherent Bayesian techniques, which are high latency and aimed at in-depth studies of all the parameters of a source, including sky position, and "triangulation-based" techniques, which exploit the data products from the search stage of the analysis to provide an almost real-time approximation of the posterior probability density function of the sky location of a detection candidate. These techniques have previously been applied to data collected during the last science runs of gravitational-wave detectors operating in the so-called initial configuration. Here, we develop and analyze methods for assessing the self consistency of parameter estimation methods and carrying out fair comparisons between different algorithms, addressing issues of efficiency and optimality. These methods are general, and can be applied to parameter estimation problems other than sky localization. We apply these methods to two existing sky localization techniques representing the two above-mentioned categories, using a set of simulated inspiralonly signals from compact binary systems with a total mass of equal to or less than 20M solar mass and nonspinning components. We compare the relative advantages and costs of the two techniques and show that sky location uncertainties are on average a factor approx. equals 20 smaller for fully coherent techniques than for the specific variant of the triangulation-based technique used during the last science runs, at the expense of a factor approx. equals 1000 longer processing time.

technique used↗
NASA NTRS2014

Materials International Space Station Experiment (MISSE): Overview, Accomplishments and Future Needs

Materials and devices used on the exterior of spacecraft in low Earth orbit (LEO) are subjected to environmental threats that can cause degradation in material properties, possibly threatening spacecraft mission success. These threats include: atomic oxygen (AO), ultraviolet and x-ray radiation, charged particle radiation, temperature extremes and thermal cycling, micrometeoroid and debris impacts, and contamination. Space environmental threats vary greatly based on spacecraft materials, thicknesses and stress levels, and the mission environment and duration. For more than a decade the Materials International Space Station Experiment (MISSE) has enabled the study of the long duration environmental durability of spacecraft materials in the LEO environment. The overall objective of MISSE is to test the stability and durability of materials and devices in the space environment in order to gain valuable knowledge on the performance of materials in space, as well as to enable lifetime predictions of new materials that may be used in future space flight. MISSE is a series of materials flight experiments, which are attached to the exterior of the International Space Station (ISS). Individual experiments were loaded onto suitcase-like trays, called Passive Experiment Containers (PECs). The PECs were transported to the ISS in the Space Shuttle cargo bay and attached to, and removed from, the ISS during extravehicular activities (EVAs). The PECs were retrieved after one or more years of space exposure and returned to Earth enabling post-flight experiment evaluation. MISSE is a multi-organization project with participants from the National Aeronautics and Space Administration (NASA), the Department of Defense (DoD), industry and academia. MISSE has provided a platform for environmental durability studies for thousands of samples and numerous devices, and it has produced many tangible impacts. Ten PECs (and one smaller tray) have been flown, representing MISSE 1 through MISSE 8, yielding long-duration space environmental performance and durability data that enable material validation, processing recertification and space qualification; improved predictions of materials and component lifetimes in space; model verification and development; and correlation factors between space-exposure and ground-facilities enabling more accurate in-space performance predictions based on ground-laboratory testing. A few of the many experiment results and observations, and their impacts, are provided. Those highlighted include examples on improved understanding of atomic oxygen scattering mechanisms, LEO coating durability results, and polymer erosion yields and their impacts on spacecraft design. The MISSE 2 Atomic Oxygen Scattering Chamber Experiment discovered that the peak flux of scattered AO was determined to be 45 deg from normal incidence, not the model predicted cosine dependence. In addition, the erosion yield (E(sub y)) of Kapton H for AO scattered off oxidized-Al is 22% of the E(sub y) of direct AO impingement. These results were used to help determine the degradation mechanism of a cesium iodide detector within the Hubble Space Telescope Cosmic Origins Spectrograph Experiment. The MISSE 6 Indium Tin Oxide (ITO) Degradation Experiment measured surface electrical resistance of ram and wake ITO coated samples. The data confirmed that ITO is a stable AO protective coating, and the results validated the durability of ITO conductive coatings for solar arrays for the Atmosphere-Space Transition 2 Explorer program. The MISSE 2, 6 and 7 Polymer Experiments have provided LEO AO Ey data on over 120 polymer and composites samples. The flight E(sub y) values were found to range from 3.05 x 10(exp -26) cu cm/atom for the AO resistant polymer CORIN to 9.14 x 10(exp -26) cu cm/atom for polyoxymethylene (POM). In addition, flying the same polymers on different missions has advanced the understanding of the AO E(sub y) dependency on solar exposure for polymers containing fluorine. The MISSE polymer results are highly requested and have impacted spacecraft design for WorldView-2 & -3, the Global Precipitation Measurement-Microwave Imager, and other spacecraft. The flight data has enabled the development of an Atomic Oxygen Erosion Predictive Tool that allows the erosion prediction of new and non-flown polymers. The data has also been used to develop a new NASA Technical Standards Handbook "Spacecraft Polymers Atomic Oxygen Durability Handbook." Many intangible benefits have also been derived from MISSE. For example, over 40 students have collaborated on Glenn's MISSE experiments, which have resulted in greater than $80K in student scholarships and awards in national and international science fairs. Students have also given presentations and won poster competition awards at international space conferences.

Flight Experiment↗
NASA NTRS2006

Deep Broad-Band Infrared Nulling Using A Single-Mode Fiber Beam Combiner and Baseline Rotation

The basic advantage of single-mode fibers for deep nulling applications resides in their spatial filtering ability, and has now long been known. However, and as suggested more recently, a single-mode fiber can also be used for direct coherent recombination of spatially separated beams, i.e. in a 'multi-axial' nulling scheme. After the first successful demonstration of deep (<2e-6) visible LASER nulls using this technique (Haguenauer & Serabyn, Applied Optics 2006), we decided to work on an infrared extension for ground based astronomical observations, e.g. using two or more off-axis sub-apertures of a large ground based telescope. In preparation for such a system, we built and tested a laboratory infrared fiber nuller working in a wavelength regime where atmospheric turbulence can be efficiently corrected, over a pass band (approx.1.5 to 1.8 micron) broad enough to provide reasonable sensitivity. In addition, since no snapshot images are readily accessible with a (single) fiber nuller, we also tested baseline rotation as an approach to detect off-axis companions while keeping a central null. This modulation technique is identical to the baseline rotation envisioned for the TPF-I space mission. Within this context, we report here on early laboratory results showing deep stable broad-band dual polarization infrared nulls <5e-4 (currently limited by detector noise), and visible LASER nulls better than 3e-4 over a 360 degree rotation of the baseline. While further work will take place in the laboratory to achieve deeper stable broad-band nulls and test off-axis sources detection through rotation, the emphasis will be put on bringing such a system to a telescope as soon as possible. Detection capability at the 500:1 contrast ratio in the K band (~2.2 microns) seem readily accessible within 50-100 mas of the optical axis, even with a first generation system mounted on a >5m AO equipped telescope such as the Palomar Hale 200 inch, the Keck, Subaru or Gemini telescopes.

single mode fibers↗
NASA NTRS2017

Detached Melt and Vapor Growth of InI in SUBSA Furnace

Indium iodide (InI) is a promising wide energy band gap nuclear detector material. It is ideal for space experiments because it is non-toxic and has a relatively low melting point of only 351 degrees Centigrade. However, it has been established that melt-grown crystals contain a large amount of second phase inclusions/precipitates. The typical size of inclusions are 1 to 27 microns in diameter, while the volume fraction of all sizes is 300 to 600 parts per million. The SEM-EDS (Scanning Electron Microscopy / Energy Dispersive X-Ray Spectroscopy) analysis of the inclusions has revealed that they all contain oxygen and some contain carbon. At present, under sponsorship of NASA and CASIS (Center for the Advancement of Science in Space), we are conducting ground-based experiments with InI in preparation for the flight experiments to be conducted in the SUBSA (Solidification Using a Baffle in Sealed Ampoules) furnace in the Microgravity Science Glovebox at the International Space Station, planned for the summer/fall of 2017. Earth-based experiments include melt and vapor growth conducted in the SUBSA ground unit, measurements of the volumetric expansion coefficient of the melt, and measurements of the wetting angle of molten InI. Finite element modeling has been conducted to optimize the design of the flight ampoules. Alloying with Tl and Ga has given promising results.

Ostrogorsky, A. G.↗
NASA NTRS2002

Assimilation of TES Water Vapor Observations

The Thermal Emission Spectrometer (TES) on the Mars Global Surveyor has made extensive observations of the Martian atmospheric water vapor column since the beginning of its mapping mission in early 1999. The results show broad agreement with the earlier Viking Mars Atmospheric Water Detector (MAWD) results (though column amounts in southern summer are higher, perhaps due to dust obscuration during the Viking mission). General circulation model (GCM) simulations of the annual Martian water cycle also show broad agreement with the TES observations. Details of the simulations depend on cloud and boundary layer parameterizations and on the adsorbing properties of the regolith. In order to make quantitative assessments of this agreement and to obtain observational values for the required physical parameters, a tracer transport data assimilation model has been developed. Model winds are derived from both tracer measurements and retrieved atmospheric temperature structures, providing a useful check of the underlying dynamical core of the GCM. By allowing detailed intercomparison between spacecraft and ground-based observations of Martian water vapor, the model should also contribute significantly to our understanding of the diurnal water cycle.

Houben, Howard↗
NASA NTRS2016

Spacecraft Fire Safety Research at NASA Glenn Research Center

Appropriate design of fire detection systems requires knowledge of both the expected fire signature and the background aerosol levels. Terrestrial fire detection systems have been developed based on extensive study of terrestrial fires. Unfortunately there is no corresponding data set for spacecraft fires and consequently the fire detectors in current spacecraft were developed based upon terrestrial designs. In low gravity, buoyant flow is negligible which causes particles to concentrate at the smoke source, increasing their residence time, and increasing the transport time to smoke detectors. Microgravity fires have significantly different structure than those in 1-g which can change the formation history of the smoke particles. Finally the materials used in spacecraft are different from typical terrestrial environments where smoke properties have been evaluated. It is critically important to detect a fire in its early phase before a flame is established, given the fixed volume of air on any spacecraft. Consequently, the primary target for spacecraft fire detection is pyrolysis products rather than soot. Experimental investigations have been performed at three different NASA facilities which characterize smoke aerosols from overheating common spacecraft materials. The earliest effort consists of aerosol measurements in low gravity, called the Smoke Aerosol Measurement Experiment (SAME), and subsequent ground-based testing of SAME smoke in 55-gallon drums with an aerosol reference instrument. Another set of experiments were performed at NASAs Johnson Space Center White Sands Test Facility (WSTF), with additional fuels and an alternate smoke production method. Measurements of these smoke products include mass and number concentration, and a thermal precipitator was designed for this investigation to capture particles for microscopic analysis. The final experiments presented are from NASAs Gases and Aerosols from Smoldering Polymers (GASP) Laboratory, with selected results focusing on realistic fuel preparations and heating profiles with regards to early detection of smoke. SAFFIRE is the upcoming large-scale fire experiment which will be executed in a Cygnus vehicle after it undocks from the ISS.

Aerosol↗
NASA NTRS2007

GISMO, a 2 mm Bolometer Camera Optimized for the Study of High Redshift Galaxies

The 2mm spectral range provides a unique terrestrial window enabling ground based observations of the earliest active dusty galaxies in the universe and thereby allowing a better constraint on the star formation rate in these objects. We present a progress report for our bolometer camera GISMO (the Goddard-IRAM Superconducting 2-Millimeter Observer), which will obtain large and sensitive sky maps at this wavelength. The instrument will be used at the IRAM 30 m telescope and we expect to install it at the telescope in 2007. The camera uses an 8 x 16 planar array of multiplexed TES bolometers, which incorporates our recently designed Backshort Under Grid (BUG) architecture. GISMO will be very efficient at detecting sources serendipitously in large sky surveys. With the background limited performance of the detectors, the camera provides significantly greater imaging sensitivity and mapping speed at this wavelength than has previously been possible. The major scientific driver for the instrument is to provide the IRAM 30 m telescope with the capability to rapidly observe galactic and extragalactic dust emission, in particular from high-zeta ULI RGs and quasar s, even in the summer season. The instrument will fill in the SEDs of high redshift galaxies at the Rayleigh-Jeans part of the dust emission spectrum, even at the highest redshifts. Our source count models predict that GISMO will serendipitously detect one galaxy every four hours on the blank sky, and that one quarter of these galaxies will be at a redshift of zeta 6.5.

Staguhn, J.↗
NASA NTRS2019

Lynx X-ray Observatory

X-ray observations are indispensable for understanding the cosmos. Their power is immense because much of the baryonic matter and the sites for the most active energy releases in the Universe are primarily observable in X-rays. For the 2030s and beyond, an X-ray observatory with power matching the capabilities in other wavebands is a necessary discovery engine for full exploration of the Universe. JWST and other upcoming major space- and ground-based facilities are expected to greatly expand science frontiers in the coming decades. is presents both a great opportunity and a challenge for a next-generation X-ray observatory. In many areas, such as tracing black holes during the CosmicDawn and understanding the formation and evolution of galaxies, an X-ray observatory is the logical next step. e challenge is that the X-ray science at these new frontiers requires expansion of capabilities by orders of magnitude beyond the current state of the art or anything already planned. Until recently, such gains were not technologically possible. is has changed thanks to recent breakthroughs and sustained maturation of key technologies for X-ray mirrors and detectors. We are reaping the fruits of U.S. investments in these areas over the past 10–15 years. An X-ray observatory that can extend the science frontiers of the post-JWST era is now entirely feasible. Lynx is the mission concept that realizes this vision. It will y revolutionary optics and instrumentation onboard a simple, proven spacecraft. In all aspects, Lynx will be a next-generation Great Observatory that is certain to make a profound impact across the astrophysical landscape. It will provide the depth and breadth to answer the fundamental questions that confront us today; just as importantly, it will have capabilities to address questions we have yet to even ask.

Gaskin, Jessica A.↗
NASA NTRS2021

Statistical Error Analysis on White-Light Filter Ratio Experiments to Measure Electron Parameters

The Filter ratio technique to remotely measure electron temperature and speed using four color filters in visible light and a polarization camera was described in detail in four articles by Reginald et al., Solar physics, (2018, 2019a, 2019b, 2020). In these four articles we quantified the systematic error associated with using models of symmetric corona to interpret results from asymmetric corona. We also showed the criteria applied to select the bandwidths of filters, and the pros and cons of replacing the traditional linear polarizer with a polarization camera to measure pB. What started in 1990s as ground experiments conducted during total solar eclipses that lasted for a few minutes lead to a balloon borne experiment lasting eight hours in 2019 and will blossom into a space experiment on the International Space Station in 2023. Due to constraints on the bandwidths of the four filters, a successful mission requires quantification of the statistical error using Monte Carlo simulation to generate two feasibility profiles, which are unique to the design parameters of the coronagraph, to comprehend the feasibility to measure temperature and speed within the desired temporal and spatial resolutions. For the statistical error analysis, we use modeled K and F corona profiles, representative theoretical diffraction, scattering, and vignetting profiles, assumed efficiencies for lenses, mirrors, and polarizers, assumed detector properties on quantum efficiency, full well depth, dark noise, and read noise, and assumed instrument properties on aperture diameter, solid angle, and pixel resolution. We hope future white-light coronagraphs will exhibit capabilities to measure electron density, temperature, and speed.

Nelson Reginald↗
NASA NTRSDate not supplied

Yeast Strain Development and Hardware Testing in Preparation of a Lunar BioSensor

With Artemis missions underway, it is clear we are going back to the Moon to stay. Before sending Astronauts for long-duration missions, it is crucial to understand the technological and biomedical countermeasures needed to protect them before they get there. We can use knowledge gained from biological CubeSats to guide the next generation of experiments to support human habitation on the Moon. Lunar Explorer Instrument for space biology Applications (LEIA) is NASA’s latest BioSensor, adapted BioSentinel, the only CubeSat to travel Beyond Low Earth Orbit. BioSentinel launched on Artemis I and is currently >50 million kilometers from Earth (as of July 2024). LEIA aims to identify biological responses to the Lunar environment, which unprotected against would pose a threat to astronauts (cancer, cardiovascular disease, neurological impairment). The suite of instruments within LEIA detects Lunar radiation using two on-board radiation sensors (ARES charged particle detector, Mini-Fast Neutron Detector), then monitors real-time biological responses to the Lunar environment via an autonomous microfluidic system, fit with 3-LED emitter and detector boards and the alamarBlue metabolic indicator dye. LEIA will use a genetic approach in addition to synthetic biology to test counter-measure production in space, with the goal to inform and protect astronauts for future Moon missions. We have conducted preliminary tests in preparation for launch to the anticipated South Pole of the Moon, optimizing the biology (strain down-selection, desiccation tolerance, radiation sensitivity) and improving the hardware (including a blue LED to detect the beta-carotene countermeasure product). Our team will discuss these findings in several parts – an overview of the LEIA mission (Mark Settles), adapting flexible CubeSat platforms for deep-space applications (Sergio Santa Maria, Kira Rienecker), developing new technologies to support LEIA ground studies (Chinmayee Govinda Raj), and yeast strain development and hardware testing in preparation for LEIA (presented here).

synthetic biology↗
NASA NTRS2012

A Traceable Ground to On-Orbit Radiometric Calibration System for the Solar Reflective Wavelength Region

This paper describes the combination of a Mie scattering spectral BSDF and BTDF albedo standard whose calibration is traceable to the NIST SIRCUS Facility or the NIST STARR II Facility. The Space-based Calibration Transfer Spectroradiometer (SCATS) sensor uses a simple, invariant optical configuration and dedicated narrow band spectral channel modules to provide very accurate, polarization-insensitive, stable measurements of earth albedo and lunar disk albedo. Optical degradation effects on calibration stability are eliminated through use of a common optical system for observations of the Sun, Earth, and Moon. The measurements from space would be traceable to SI units through preflight calibrations of radiance and irradiance at NIST's SIRCUS facility and the invariant optical system used in the sensor. Simultaneous measurements are made in multiple spectral channels covering the solar reflective wavelength range of 300 nm to 2.4 microns. The large dynamic range of signals is handled by use of single-element, highly-linear detectors, stable discrete electronic components, and a non imaging optical configuration. Up to 19 spectral modules can be mounted on a single-axis drive to give direct pointing at the Earth and at least once per orbit view of the Sun and Moon. By observing the Sun on every orbit, the most stringent stability requirements of the system are limited to short time periods. The invariant optical system for both radiance and irradiance measurements also give excellent transfer to-orbit SI traceability. Emerging instrumental requirements for remotely sensing tropospheric trace species have led to a rethinking by some of the paradigm for Systeme International d'Unites (SI) traceability of the spectral irradiance and radiance radiometric calibrations to spectral albedo (sr(exp -1)) which is not a SI unit. In the solar reflective wavelength region the spectral albedo calibrations are tied often to either the spectral albedo of a solar diffuser or the Moon. This new type of Mie scattering diffuser (MSD) is capable of withstanding high temperatures, and is more Lambertian than Spectralon(tm). It has the potential of covering the entire solar reflective wavelength region. Laboratory measurements have shown that the specular reflectance component is negligible, and indicate that internal absorption by multiple scattering is small. This MSD, a true volume diffuser, exhibits a high degree of radiometric stability which suggests that measurements at the National Institute of Standards and Technology (NIST) could provide a spectral albedo standard. Measurements have been made of its radiometric stability under a simulated space environment of high energy gamma rays, high energy protons, and UV radiation from ambient down to the vacuum ultraviolet H Lyman alpha at 121.6 nm for its eventual use in space as a solar diffuser.

Heath, Donald F.↗
NASA NTRS2020

Comparing complex impedance and bias step measurements of Simons Observatory transition edge sensors

The Simons Observatory (SO) will perform ground-based observations of the cosmic microwave background (CMB) with several small and large aperture telescopes, each outfitted with thousands to tens of thousands of superconducting aluminum manganese (AlMn) transition-edge sensor bolometers (TESs). In-situ characterization of TES responsivities and effective time constants will be required multiple times each observing-day for calibrating time-streams during CMB map-making. Effective time constants are typically estimated in the field by briefly applying small amplitude square-waves on top of the TES DC biases, and fitting exponential decays in the bolometer response. These so-called “bias step” measurements can be rapidly implemented across entire arrays and therefore are attractive because they take up little observing time. However, individual detector complex impedance measurements, while too slow to implement during observations, can provide a fuller picture of the TES model and a better understanding of its temporal response. Here, we present the results of dark TES characterization of many prototype SO bolometers and compare the effective thermal time constants measured via bias steps to those derived from complex impedance data.

Nicholas F. Cothard↗
NASA NTRS2016

Inland and Near Shore Water Profiles Derived from the High Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532 nm laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in icecaps, sea ice and vegetation, the polar-orbital satellite will observe global surface water during its designed three year life span, including inland water bodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype or the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the datasets of three MABEL transects observed from 20 km above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 km in length and included the middle Chesapeake Bay, the near shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision of approximately 5-7 cm per 100m segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR0, were observed over a range of 1.3 to 9.3 meters depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when solar background rate was low. Near shore bottom reflectance was detected only at the Lake Mead site down to maximum of 10 m under a clear night sky and low turbidity of approximately 1.6 Nephelometric Turbidity Units (NTU). The overall results suggest that the feasibility of retrieving operational surface water height statistics from space-based photon counting systems such as ATLAS is very high for resolutions down to about 100m, even in partly cloudy conditions. The capability to observe subsurface backscatter profiles is achievable but requires much longer transects of several hundreds of meters.

Topographic↗
NASA NTRS1968

Data Acquisition and Prompt Analysis System for High Altitude Balloon Experiments

An inexpensive and simple data acquisition system has been developed for balloon borne experiments and has been tested with a gamma ray detector in a balloon flight launched from Palestine, Texas. The detector used for the test consisted of an NaI(T1) scintillation crystal encased in a 1/8 in. plastic scintillator-charged particle shield. The combination was viewed by a single photomultiplier and charged particle gating was accomplished by a conventional phoswich discriminator. The pulse height analysis of the NaI events, not associated with prompt charged particle interactions, is accomplished by converting to a time spectrum using an airborne height to time converter. A range of pulse widths from 5 microseconds to 250 microseconds corresponds to energy losses in NaI from 100 to 1000 keV. The time spectrum information, along with charged particle events and barometric pressure, is fed to a mixer which modulates a 252.4 Mc FM transmitter. The original scintillator spectrum is recovered on the ground utilizing conversion circuitry at the receiver video output and a 128 channel commercial pulse height analyzer. The charged particle events of standard time width are stored with the spectrum at a fixed channel position and are therefore represented by a sharp line riding on the lower part of the NaI energy loss spectrum. An energy loss greater than 1000 keV is presented by the maximum pulse width of the converter and stored in the last analyzer channel. Barometric pressure data is transmitted by low frequency modulation of the sme FM carrier. In flight operation, the receiver video output can be recorded on a wide band tape recorder and simultaneously analyzed by the 128 channel analyzer, or the telemetered data can be analyzed later. The flight system features high pulse resolution, essentially instantaneous time response, high data rate, and flexibility; and is of modest cost. A detailed description of the system and operating performance is discussed.

Sarkady, A. A.↗
NASA NTRS2016

Inland and Near-Shore Water Profiles Derived from the High-Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532-nanometer laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in ice caps, sea ice, and vegetation, the polar-orbiting satellite will observe global surface water during its designed three-year life span, including inland waterbodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype, the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high-altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the data sets of three MABEL transects observed from 20 kilometers above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 kilometers in length and included the middle Chesapeake Bay, the near-shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision ofapproximately 5-7 centimeters per 100-meter segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR (sub 0), were observed over a range of 1.3 to 9.3 meters, depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when the solar background rate was low. Near-shore bottom reflectance was detected only at the Lake Mead site down to a maximum of 10 meters under a clear night sky and low turbidity of approximately 1.6 Nephelometric Turbidity Units (NTU). The overall results suggest that the feasibility of retrieving operational surface water height statistics from space-based photon counting systems such as ATLAS is very high for resolutions down to about 100 meters, even in partly cloudy conditions. The capability to observe subsurface backscatterprofiles is achievable but requires much longer transects of several hundreds of meters.

inland↗
NASA NTRSDate not supplied

The ARADS Project as an Astrobiological Survey Mission Prototype

An astrobiological survey prior to human arrival will be important for preservation of signs of any existing or past evidence of Martian life, to reduce the risk of unintentional forward contamination of Martian environments in which terrestrial microbes might be able to gain a foothold (e.g., [1]), and to potentially protect the health of any human crews and enable their safe return to Earth. Evaluating for the presence of life and biosignatures may become a critical-path Mars exploration precursor in the not-so-far future, circa 2030-35. The near-subsurface, with its potential combination of volatiles, vapor exchange with the surface, and shelter from surface radiation, will be a primary initial target for in-situ astrobiological investigation. Sample acquisition, drilling and sample handling are key elements of robotic missions that target the subsurface [2], as well as near-surface ground ice deposits. In the mid 2000s, the Mars Astrobiology Field Laboratory (AFL) was proposed as a follow-on mission concept to the Mars Science Laboratory (MSL)/Curiosity rover mission [3]. The AFL would have included precision drilling to 2m, automated sample handling and remote processing of cores. However, the AFL concept needed further development and maturation. The Atacama Rover Astrobiology Drilling Studies (ARADS) project concept [4] was in part AFL-inspired. The 2014 ARADS concept included a medium sized rover, with habitability instruments, including the Phoenix Wet Chemistry Laboratory (WCL) [5], and an enhanced version of the ExoMars Mars Organic Molecule Analyzer (MOMA) Laser Desorption-Linear Ion Trap Mass Spectrometer (LITMS) [6]. ARADS likewise included two biosignature detection instruments -- the Signs of Life Detector (SOLID) immunoassay instrument [7,8] and the Chemical Laptop-derived [9] Planetary In-Situ Capillary Electrophoresis System (PISCES), while mitigating Planetary Protection-relevant contamination issues [10]. ARADS project objectives were to demonstrate the potential science return for such a mission in the context of the search for evidence of life, and technically to demonstrate the feasibility of roving with drilling missions to Mars. ARADS technology goals targeted analog-site demonstrations of automated drilling and sampling, integrated with its mobile habitability and biosignature detection instruments. And ARADS science operations goals developed remote science, contamination mitigation, and communications methods to enable simulating AFL-like science operations with time delays, directed by a remote science team[11]. Five subsequent Mars analog site field demonstrations (in Chile’s hyperarid Atacama Desert, 2016-19) provided a step-by-step development pathway for the ARADS platform’s science capabilities and systems integration, culminating in an integrated remote roving mission simulation in the final ARADS year (2019).

biosignatures↗
NASA NTRSDate not supplied

RadLab and the Environmental Data Application Dashboard: Graphical and Programming Interfaces for Interrogation of Space Telemetry Data

Sensors on the International Space Station (ISS) and multiple spacecraft elsewhere in Earth orbit and in deep space continuously monitor and collect environmental data, transmitting this information back to Earth. These data include ionizing radiation and, on the ISS, CO2, relative humidity levels, and temperature, and are of great importance to space biology research. Ionizing radiation in particular has been established in ground-based experiments as being correlated with increased risk of carcinogenesis and cardiovascular and neurological effects. Looking ahead to future long duration crewed missions beyond low Earth orbit, the ability to study how factors including CO2 levels, light cycle, temperature modulate the response to ionizing radiation and microgravity is essential. To date, access to these data has been fragmented across space agencies, spacecraft, and databases. To address this issue, NASA’s Open Science Data Repository (osdr.nasa.gov) has developed two Web applications: the Environmental Data Application (EDA) and a radiation-specific RadLab. Each consists of an API (application programming interface) and an associated GUI (graphical user interface) that provide single points of access to the data. To date, OSDR has focused on the sensors from payloads and radiation detectors located on the ISS. The Web applications process telemetry information and associated data, such as spacecraft location and orientation, from multiple international databases. The applications’ request syntax enables users to interrogate these data by craft, sensor type, time range, radiation type (galactic cosmic rays, solar particle events, the contribution of the South Atlantic Anomaly), facilitating arbitrary comparisons of original source data at varying time resolutions. The applications provide programmatic access for use in computational pipelines and GUIs for data visualization and exploration, making these data FAIR (Findable, Accessible, Interoperable, and Reusable), complementing the biological data contained in OSDR, and providing the space science community with a valuable resource for scientific analyses.

radiation↗
NASA NTRS2004

THIS: A Next Generation Tuneable Heterodyne Infrared Spectrometer for SOFIA

A new infrared heterodyne instrument has been developed which allows the use of both tuneable diode lasers (TDL) and quantum cascade lasers (QCL) as local oscillators (LO). The current frequency tuning range of our system extends from 900 to 1100/cm depending on the availability of lasers but is planned to be extended to 600/cm soon. The IF-bandwidth is 1.4 GHz using an acousto-optical spectrometer (AOS). The frequency resolution and stability of the system is approximately 10(exp 7). Currently, mercury-cadmium-telluride (MCT) detectors are used as mixers while new devices like quantum-well-infrared-photodetectors (QWIP) and hot-electron-bolometers (HEB) are investigated. The IF-bandwidth can be extended to about 3 GHz by using a new broadband acousto-optical spectrometer presently under development. The instrument is fully transportable and can be attached to any infrared or optical telescope. The semiconductor laser is stabilized to a Fabry-Perot ring-resonator, which is also used as an efficient diplexer to superimpose the local-oscillator and the signal radiation. As a first step measurements of trace gases in Earth's atmosphere and non-LTE emission from Venus' atmosphere were carried out as well as observations of molecular features in sunspots. Further astronomical observations from ground-based telescopes and the airborne observatory SOFIA are planned for the future. Of particular interest are molecules without a permanent dipole moment like H2, CH4, C2H2 etc.

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