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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 1,405 records · Page 78
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Gamma-Ray Bursts: A Mystery Story

With the success of the Swift Gamma-Ray Burst Explorer currently in orbit, this is quite an exciting time in the history of Gamma Ray Bursts (GRBs). The study of GRBs is a modern astronomical mystery story that began over 30 years ago with the serendipitous discovery of these astronomical events by military satellites in the late 1960's. Until the launch of BATSE on the Compton Gamma-ray Observatory, astronomers had no clue whether GRBs originated at the edge of our solar system, in our own Milky Way Galaxy or incredibly far away near the edge of the observable Universe. Data from BATSE proved that GRBs are distributed isotropically on the sky and thus could not be the related to objects in the disk of our Galaxy. Given the intensity of the gamma-ray emission, an extragalactic origin would require an astounding amount of energy. Without sufficient data to decide the issue, a great debate continued about whether GRBs were located in the halo of our own galaxy or were at extragalactic - even cosmological distances. This debate continued until 1997 when the BeppoSAX mission discovered a fading X-ray afterglow signal in the same location as a GRB. This discovery enabled other telescopes, to observe afterglow emission at optical and radio wavelengths and prove that GRBs were at cosmological distances by measuring large redshifts in the optical spectra. Like BeppoSAX Swift, slews to new GRB locations to measure afterglow emission. In addition to improved GRB sensitivity, a significant advantage of Swift over BeppoSAX and other missions is its ability to slew very quickly, allowing x-ray and optical follow-up measurements to be made as early as a minute after the gamma-ray burst trigger rather than the previous 6-8 hour delay. Swift afterglow measurements along with follow-up ground-based observations, and theoretical work have allowed astronomers to identify two plausible scenarios for the creation of a GRB: either through core collapse of super massive stars or colliding compact objects in distant galaxies. The pieces of the puzzle are beginning to fall into place and yet the story isn't quite finished. I will frame the history of gamma-ray bursts as a mystery story and will end with a description of what we still don't know and what we'll have to do to get the next clues.

Parsons, Ann↗
NASA NTRS2007

Optimizations of a Hardware Decoder for Deep-Space Optical Communications

The National Aeronautics and Space Administration has developed a capacity approaching modulation and coding scheme that comprises a serial concatenation of an inner accumulate pulse-position modulation (PPM) and an outer convolutional code [or serially concatenated PPM (SCPPM)] for deep-space optical communications. Decoding of this code uses the turbo principle. However, due to the nonbinary property of SCPPM, a straightforward application of classical turbo decoding is very inefficient. Here, we present various optimizations applicable in hardware implementation of the SCPPM decoder. More specifically, we feature a Super Gamma computation to efficiently handle parallel trellis edges, a pipeline-friendly 'maxstar top-2' circuit that reduces the max-only approximation penalty, a low-latency cyclic redundancy check circuit for window-based decoders, and a high-speed algorithmic polynomial interleaver that leads to memory savings. Using the featured optimizations, we implement a 6.72 megabits-per-second (Mbps) SCPPM decoder on a single field-programmable gate array (FPGA). Compared to the current data rate of 256 kilobits per second from Mars, the SCPPM coded scheme represents a throughput increase of more than twenty-six fold. Extension to a 50-Mbps decoder on a board with multiple FPGAs follows naturally. We show through hardware simulations that the SCPPM coded system can operate within 1 dB of the Shannon capacity at nominal operating conditions.

quadratic polynomial interleaver↗
NASA NTRS2011

Small, Fast TES Microcalorimeters with Unprecedented X-ray Spectral Performance

Driven initially by the desire for X-ray microcalorimeter arrays suitable for imaging the dynamic solar corona, we have developed a transition-edge-sensor (TES) microcalorimeter optimization that exhibits a unique combination of high spectral resolving power and a wide X-ray bandpass. These devices have achieved spectral performance of dE approximately 1.3 eV FWHM at 1.5 keV, 1.6 eV at 6 keV, and 2.0 eV at 8 keV, using small TESs (e.g., approximately 35 micron x 35 micron) that operate in a regime in which the superconducting transition is highly current dependent. In order to accommodate high X-ray count rates, the devices sit directly on a solid substrate instead of on membranes, and we use an embedded heatsinking layer to reduce pixel-to-pixel crosstalk. We will present results from devices with a range of TES and absorber sizes, and from device wafers with varied embedded heatsink materials. This contribution will focus on count-rate capabilities, including a discussion of the trade-off between count rate and energy resolution, and the heatsinking design. We will also present preliminary tests of array readout using a code-division multiplexed SQUID readout scheme, which may be necessary to enable large arrays of these fast devices.

Eckart, M. E.↗
NASA NTRS2012

Fabrication of Microstripline Wiring for Large Format Transition Edge Sensor Arrays

We have developed a process to integrate microstripline wiring with transition edge sensors (TES). The process includes additional layers for metal-etch stop and dielectric adhesion to enable recovery of parameters achieved in non-microstrip pixel designs. We report on device parameters in close-packed TES arrays achieved with the microstrip process including R(sub n), G, and T(sub c) uniformity. Further, we investigate limits of this method of producing high-density, microstrip wiring including critical current to determine the ultimate scalability of TES arrays with two layers of wiring.

Chervenak, James A.↗
NASA NTRS2017

Scientific Investigations Associated with the Human Exploration of Mars in the Next 35 Years

A human mission to Mars would present an unprecedented opportunity to investigate the earliest history of the solar system. This history that has largely been overwritten on Earth by active geological processing throughout its history, but on Mars, large swaths of the ancient crust remain exposed at the surface, allowing us to investigate martian processes at the earliest time periods when life first appeared on the Earth. Mars' surface has been largely frozen in place for 4 billion years, and after losing its atmosphere and magnetic field what re-mains is an ancient landscape of former hydrothermal systems, river beds, volcanic eruptions, and impact craters. This allows us to investigate scientific questions ranging from the nature of the impact history of the solar system to the origins of life. We present here a summary of the findings of the Human Science Objectives Science Analysis Group, or HSO-SAG chartered by MEPAG in 2015 to address science objectives and landing site criteria for future human missions to Mars (Niles, Beaty et al. 2015). Currently, NASA's plan to land astronauts on Mars in the mid 2030's would allow for robust human exploration of the surface in the next 35 years. We expect that crews would be able to traverse to sites up to 100 km away from the original landing site using robust rovers. A habitat outfitted with state of the art laboratory facilities that could enable the astronauts to perform cutting edge science on the surface of Mars. Robotic/human partnership during exploration would further enhance the science return of the mission.

Niles, P. B.↗
NASA NTRS2019

Spacecraft Lighting to Mitigate Microbial Growth

In this innovation project, we investigated the usage of narrow band violet light (408 nm) to attenuate the growth of bacteria typically found on ISS. Violet light is less hazardous than UV light and it can transmit through plastics, such as clear acrylics, making it possible to incorporate into large surface lamps and acrylic or polycarbonate based optical light guides. This study built a custom LED surface panel that was edge lit by an array of 408 nm violet LEDS. The optical light guide technology used in the lamp and the 408 nm violet LEDs are available on the market from multiple vendors. The application of the concept of using violet light driven LED panels and optical light guides is to integrate the paneling into spacecraft architectural surfaces for the automation of a light based microbial countermeasure that could enhance current cleaning methods used in areas on spacecraft prone to microbial growth.

Clark, Toni A.↗
NASA NTRSDate not supplied

International Space Station (ISS) Environmental Control and Life Support (ECLS) System Overview of Events 2022

Nov 20th, 2022 marks the 24th anniversary of the beginning of construction of the International Space Station(ISS). The ECLS system is constantly changing to meet the needs of current missions and future exploration. The ISS has become the laboratory that was always envisioned, allowing for an ever-growing class of exploration level technologies that will propel the stage forward as humanity advances beyond Low Earth Orbit (LEO). This paper will review the past year, and look towards the future for each U.S. ECLS subsystem. The impacts, challenges, and successes related to the intermingling of incumbent and cutting edge technologies are summarily discussed in this paper.

Steven F Balistreri↗
NASA NTRSDate not supplied

International Space Station (ISS) Environmental Control and Life Support (ECLS) System Overview of Events 2023

November 20th, 2023 marks the 25th anniversary of the beginning of construction of the International Space Station (ISS). The ECLS system is constantly changing to meet the needs of current missions and future exploration. The ISS has become the laboratory that was always envisioned, allowing for an ever-growing class of exploration level technologies that will propel the stage forward as humanity advances beyond Low Earth Orbit (LEO). This paper will review the past year, and look towards the future for each U.S. ECLS subsystem. The impacts, challenges, and successes related to the intermingling of incumbent and cutting edge technologies are summarily discussed in this paper.

Steven F Balistreri Jr.↗
NASA NTRSDate not supplied

International Space Station (ISS) Environmental Control and Life Support (ECLS) System Overview of Events 2023

Nov 20th, 2023 marks the 25th anniversary of the beginning of construction of the International Space Station (ISS). The ECLS system is constantly changing to meet the needs of current missions and future exploration. The ISS has become the laboratory that was always envisioned, allowing for an ever-growing class of exploration level technologies that will propel the stage forward as humanity advances beyond Low Earth Orbit (LEO). This paper will review the past year, and look towards the future for each U.S. ECLS subsystem. The impacts, challenges, and successes related to the intermingling of incumbent and cutting edge technologies are summarily discussed in this paper.

Steven F Balistreri, Jr↗
NASA NTRS2024

International Space Station (ISS) Environmental Control and Life Support (ECLS) System Overview of Events 2023

Nov 20th, 2023 marks the 25th anniversary of the beginning of construction of the International Space Station (ISS). The ECLS system is constantly changing to meet the needs of current missions and future exploration. The ISS has become the laboratory that was always envisioned, allowing for an ever-growing class of exploration level technologies that will propel the stage forward as humanity advances beyond Low Earth Orbit (LEO). This paper will review the past year, and look towards the future for each U.S. ECLS subsystem. The impacts, challenges, and successes related to the intermingling of incumbent and cutting edge technologies are summarily discussed in this paper.

Kristina Robinson↗
NASA NTRSDate not supplied

Implementation of a Hybrid Edge Node-Centroid Node Approach for the Generation of Reduced Thermal Models

Reduced thermal models are often required for delivery to organizations that manage observatory or launch models at the highest levels of assembly. However, the effort to generate reduced models, and verify against their detailed counterparts, is a challenge that has not yet been conclusively solved. Higher level organizations often place a limit on the number of nodes for delivered models with the assumption that smaller models generally result in less computation time. However, the burden of producing and verifying the accuracy of the reduced models is placed primarily on the lower-level organizations, which in turn consumes resources needed to produce these models. Limiting the total number of allowable nodes may also prevent users from taking full advantage of software capabilities that allow for faster generation of models, such as finite elements, which generally require more nodes than older centroid based models. A methodology using Thermal Desktop was described in 2010 which used: (1) finite elements and edge nodes for a conduction matrix, (2) centroid nodes for capacitance and radiative computations, and (3) the super network feature to produce a conduction matrix based only on the centroid nodes. At that time, the methodology was clear, but the implementation would have had to be done manually; however, with the inclusion of the OpenTD API, this methodology can now be implemented programmatically and for the first time, be a viable approach for the generation of reduced models. The approach was implemented and developed at the NASA Goddard Space Flight Center (GSFC) for the Capture, Containment, and Return System (CCRS) payload on the Earth Return Orbiter (ERO) as part of the Mars Sample Return (MSR) mission, resulting in the TCYEE tool. ERO features a spacecraft bus provided by Airbus through the European Space Agency (ESA) with node limitations on the delivered CCRS model provided by GSFC. TCYEE was used to generate the reduced model for this delivery and the predictions compared favorably to the detailed model currently in use for the thermal performance evaluation. Furthermore, TCYEE is being explored for potential use on the Roman Space Telescope (RST) for the generation of reduced models for delivery to the launch provider, which also has node limit requirements on the RST observatory model for use in launch simulation analyses. This paper describes the methodology, its implementation, and compares the performance of reduced models generated by TCYEE to their detailed counterparts.

Thermal desktop↗
NASA NTRSDate not supplied

Enabling Reliable, Fault-Tolerant Autonomous Lunar Habitats with High-Performance Spaceflight Computing

The lunar surface presents unfavorable constraints and harsh living conditions. To address these challenges, autonomous habitats will require complex integrated systems that combine advanced software, high-performance hardware, and cutting-edge sensors to ensure sustainability, safety, and operational efficiency. Consequently, maintaining a sustainable presence on the Moon requires reliable infrastructure and efficient development, precise monitoring, and utilization of resources within a lunar installation. These elements are essential not only to ensure that lunar settlement can be long-term, self-sustaining, and resource-efficient, but also to serve as a foundation for future missions and eventual human habitation on Mars. Humans are not native to the Moon; therefore, our survival and ability to thrive will depend on autonomous systems that can foster safety and resilience through high-availability architectures, graceful degradation, and highly fault-tolerant spaceflight hardware capable of continuing operation during failures. This requires advanced human-rated distributed systems architectures with specialized electronics, scalable capabilities, and an integrated design approach. Unlike current practices focused on short-term missions and regularly maintained components, permanent lunar compute systems must be designed for extended operations beyond mission durations. This paper explores the necessity of transitioning toward fault- tolerant, highly autonomous hardware systems designed for multi-year missions. It also identifies critical subsystems that require high levels of autonomy, supported by radiation-hardened processors and extreme thermal loads, which are essential to mitigate long-term degradation and ensure sustainable lunar habitation. Finally, the paper aligns with NASA’s identified Civil Space Shortfalls, particularly in high-performance onboard computing, advanced data acquisition, extreme-environment avionics, radiation monitoring and countermeasures, and autonomous health management. It proposes NASA’s new High-Performance Spaceflight Computing (HPSC) processor as a turnkey solution, delivering 100 times the performance-per-watt of legacy rad-hard CPUs and enabling onboard AI, edge computing, and fault-tolerant features essential for sustained lunar autonomy and beyond.

Sarkis S Mikaelian↗
DOE OSTI2024

Development of AlGaN‐Based Deep‐Ultraviolet Avalanche Photodetectors—Toward Their Intrinsic Characteristics

Al 0.6 Ga 0.4 N deep‐UV p–i–n avalanche photodiodes (APDs) are demonstrated grown by metalorganic chemical vapor deposition (MOCVD) on a (0001) c‐plane aluminum nitride (AlN) bulk substrate and fabricated both with and without an ion implantation process for mesa‐edge electric‐field termination. Three design considerations are taken into account: the optical absorption of the AlN bulk substrate, the photosensitivity of the APD, and the breakdown electric field. The MOCVD growth conditions of the AlGaN APD layers are optimized. Then, a detailed description of the seven device fabrication steps of the APDs is provided, which includes nitrogen ion implantation. The APDs fabricated by the ion implant process exhibit a dark‐current density under low reverse bias ≈1 × 10 −9 A cm −2 . This is one order of magnitude lower than the APD fabricated without ion implantation from the same wafer. The breakdown voltage of the APD is ≈−140 V. The calculated optical gain of the ion‐implanted APD beyond avalanche breakdown is ≈5.2 × 10 5 (current limited) and the device has an average zero‐bias photoresponse of ≈68 mA W −1 at a wavelength of 250 nm.

Jeong, Hoon [Department of Electronic Engineering ↗
DOE OSTI2024

Electrostatically controlled spin polarization in Graphene-CrSBr magnetic proximity heterostructures

Abstract The magnetic proximity effect can induce a spin dependent exchange shift in the band structure of graphene. This produces a magnetization and a spin polarization of the electron/hole carriers in this material, paving the way for its use as an active component in spintronics devices. The electrostatic control of this spin polarization in graphene has however never been demonstrated so far. We show that interfacing graphene with the van der Waals antiferromagnet CrSBr results in an unconventional manifestation of the quantum Hall effect, which can be attributed to the presence of counterflowing spin-polarized edge channels originating from the spin-dependent exchange shift in graphene. We extract an exchange shift ranging from 27 – 32 meV, and show that it also produces an electrostatically tunable spin polarization of the electron/hole carriers in graphene ranging from − 50% to + 69% in the absence of a magnetic field. This proof of principle provides a starting point for the use of graphene as an electrostatically tunable source of spin current and could allow this system to generate a large magnetoresistance in gate tunable spin valve devices.

Science & Technology - Other Topics↗
DOE OSTI2022

Atomistic measurement and modeling of intrinsic fracture toughness of two-dimensional materials

Quantifying the intrinsic mechanical properties of two-dimensional (2D) materials is essential to predict the long-term reliability of materials and systems in emerging applications ranging from energy to health to next-generation sensors and electronics. Currently, measurements of fracture toughness and identification of associated atomistic mechanisms remain challenging. Herein, we report an integrated experimental–computational framework in which in-situ high-resolution transmission electron microscopy (HRTEM) measurements of the intrinsic fracture energy of monolayer MoS 2 and MoSe 2 are in good agreement with atomistic model predictions based on an accurately parameterized interatomic potential. Changes in crystalline structures at the crack tip and crack edges, as observed in in-situ HRTEM crack extension tests, are properly predicted. Such a good agreement is the result of including large deformation pathways and phase transitions in the parameterization of the inter-atomic potential. The established framework emerges as a robust approach to determine the predictive capabilities of molecular dynamics models employed in the screening of 2D materials, in the spirit of the materials genome initiative. Moreover, it enables device-level predictions with superior accuracy (e.g., fatigue lifetime predictions of electro- and opto-electronic nanodevices).

Zhang, Xu↗
DOE OSTI2026

Green Methanol via an Integrated Direct Air Capture, CO 2 Electrolyzer, and Hydrogenation Reactor

This project pioneered a groundbreaking reactor design to produce green methanol by harnessing the electrochemical CO 2 reduction reaction (eCO 2 RR), a cornerstone of power-to-fuels technology. The effort integrated three innovative technologies to achieve carbon-neutral methanol production at a target cost of under $\$$800/ton: 1. Direct Air Capture (DAC): Using a cutting-edge sorbent material developed at Holocene, scalable models were developed to integrate captured atmospheric CO₂ into the reactor system. 2. Intermediate-Temperature CO 2 Electrolyzer: Developed by the University of Tennessee (UTK), this electrolyzer utilizes a cost-effective, proton-conducting solid acid electrolyte (CsH 2 PO 4 , CDP) and a mixed-metal oxide cathode. It achieves high faradaic efficiencies (>98%) by effectively suppressing hydrogen evolution at high current densities, converting CO 2 to CO with remarkable selectivity. 3. Catalysis and Reactor Engineering: Oak Ridge National Laboratory (ORNL) contributed world-class expertise in heterogeneous catalysis and reactor design. Their advanced ASPEN modeling drove systems integration and supported techno-economic and life cycle analyses. This effort was further bolstered by partnerships with industry leaders Air Company and Plug Power, who provided critical guidance on scaling, systems engineering, and the integration of water electrolyzers into large-scale operations. During Phase 1, the team focused on modeling and validating a lab-scale reactor demonstrating the feasibility of the integrated approach. Key accomplishments include a 52% increase in current density at 0.8 V while maintaining >98% CO faradaic efficiency, successful 10× scale-up of the electrolyzer with performance within 5% of coin-cell results, best-in-class durability (168-hour test at 0.6 V with 0.14 mA/cm 2 -h degradation), validated TEA confirming the $\$$800/ton methanol target, and completed preliminary LCA showing potential for net-negative GHG emissions under renewable energy scenarios.

10 SYNTHETIC FUELS↗
NASA NTRS1978

An unusual lightning flash at Kennedy Space Center

A lightning flash that struck the 150-meter weather tower at Kennedy Space Center was studied by several research groups using various techniques. The flash had unusually large peak currents and a stepped leader of relatively short duration. The charged regions neutralized by the three return strokes were located within a horizontal layer between heights of about 6 and 8 kilometers, where environmental temperatures were about -10 to -20 C. The charge source for the first return stroke coincided with a vertical shaft of precipitation inferred to have been graupel or hail. Charge sources for subsequent strokes were near the edge of the detectable precipitation echo. The overall channel length was about 10 kilometers. A vertically oriented intracloud discharge occurred after the three return strokes.

Uman, M. A.↗
NASA NTRS1978

Description and preliminary calibration results for the Langley hypersonic CF4 tunnel

A detailed description of the hypersonic CF4 tunnel is presented along with discussion of the basic components, instrumentation, and operating procedure. Operational experience with the CF4 reclaimer and lead-bath heater is discussed. Comparison of measured and predicted shock detachment distance on a sphere and pressure distributions measured on a sharp leading-edge flat plate revealed the absence of significant flow nonuniformity and lent creditability to predicted free stream flow conditions. The economic operation of this facility centers about the CF4 reclaimer, which was designed to operate at an efficiency of 90 to 95 percent. A number of modifications were made to the reclaimer system to improve its performance, and presently, the system reclaims approximately 75 percent of the test gas. Even with current budgetary constraints, this efficiency permits the CF4 tunnel to be operated as a viable research wind tunnel.

Midden, R. E.↗