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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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NASA NTRS2014

The Nuclear Thermal Propulsion Stage (NTPS): A Key Space Asset for Human Exploration and Commercial Missions to the Moon

The nuclear thermal rocket (NTR) has frequently been discussed as a key space asset that can bridge the gap between a sustained human presence on the Moon and the eventual human exploration of Mars. Recently, a human mission to a near Earth asteroid (NEA) has also been included as a "deep space precursor" to an orbital mission of Mars before a landing is attempted. In his "post-Apollo" Integrated Space Program Plan (1970 to 1990), Wernher von Braun, proposed a reusable Nuclear Thermal Propulsion Stage (NTPS) to deliver cargo and crew to the Moon to establish a lunar base initially before sending human missions to Mars. The NTR was selected because it was a proven technology capable of generating both high thrust and high specific impulse (Isp approx. 900 s)-twice that of today's best chemical rockets. During the Rover and NERVA programs, 20 rocket reactors were designed, built and successfully ground tested. These tests demonstrated the (1) thrust levels; (2) high fuel temperatures; (3) sustained operation; (4) accumulated lifetime; and (5) restart capability needed for an affordable in-space transportation system. In NASA's Mars Design Reference Architecture (DRA) 5.0 study, the "Copernicus" crewed NTR Mars transfer vehicle used three 25 klbf "Pewee" engines-the smallest and highest performing engine tested in the Rover program. Smaller lunar transfer vehicles-consisting of a NTPS with three approx. 16.7 klbf "SNRE-class" engines, an in-line propellant tank, plus the payload-can be delivered to LEO using a 70 t to LEO upgraded SLS, and can support reusable cargo delivery and crewed lunar landing missions. The NTPS can play an important role in returning humans to the Moon to stay by providing an affordable in-space transportation system that can allow initial lunar outposts to evolve into settlements capable of supporting commercial activities. Over the next decade collaborative efforts between NASA and private industry could open up new exploration and commercial opportunities for both organizations. With efficient NTP, commercial habitation and crew delivery systems, a "mobile cislunar research station" can transport crews to small NEAs delivered to the E-ML2 point. Also possible are week-long "lunar tourism" missions that can carry passengers into lunar orbit for sightseeing (and plenty of picture taking), then return them to Earth orbit where they would re-enter and land using a small reusable lifting body based on NASA's HL-20 design. Mission descriptions, key vehicle features and operational characteristics are described and presented.

Borowski, Stanley K.↗

NASA NTRS2015

A Future Large-Aperture UVOIR Space Observatory: Key Technologies and Capabilities

We present the key technologies and capabilities that will enable a future, large-aperture ultravioletopticalinfrared (UVOIR) space observatory. These include starlight suppression systems, vibration isolation and control systems, lightweight mirror segments, detector systems, and mirror coatings. These capabilities will provide major advances over current and near-future observatories for sensitivity, angular resolution, and starlight suppression. The goals adopted in our study for the starlight suppression system are 10-10 contrast with an inner working angle of 20 milliarcsec and broad bandpass. We estimate that a vibration and isolation control system that achieves a total system vibration isolation of 140 dB for a vibration-isolated mass of 5000 kg is required to achieve the high wavefront error stability needed for exoplanet coronagraphy. Technology challenges for lightweight mirror segments include diffraction-limited optical quality and high wavefront error stability as well as low cost, low mass, and rapid fabrication. Key challenges for the detector systems include visible-blind, high quantum efficiency UV arrays, photon counting visible and NIR arrays for coronagraphic spectroscopy and starlight wavefront sensing and control, and detectors with deep full wells with low persistence and radiation tolerance to enable transit imaging and spectroscopy at all wavelengths. Finally, mirror coatings with high reflectivity ( 90), high uniformity ( 1) and low polarization ( 1) that are scalable to large diameter mirror substrates will be essential for ensuring that both high throughput UV observations and high contrast observations can be performed by the same observatory.

Instrument↗

NASA NTRS2015

Turboelectric Aircraft Drive Key Performance Parameters and Functional Requirements

The purpose of this paper is to propose specific power and efficiency as the key performance parameters for a turboelectric aircraft power system and investigate their impact on the overall aircraft. Key functional requirements are identified that impact the power system design. Breguet range equations for a base aircraft and a turboelectric aircraft are found. The benefits and costs that may result from the turboelectric system are enumerated. A break-even analysis is conducted to find the minimum allowable electric drive specific power and efficiency that can preserve the range, initial weight, operating empty weight, and payload weight of the base aircraft.

Jansen, Ralph H.↗

NASA NTRS2015

Key Recent Scientific Results from the Opportunity Rover's Exploration of Endeavour Crater, Mars

The Opportunity Rover is currently in its 11th year of operations, exploring the rim of the approximately 22 km wide Noachian-age Endeavour Crater. Opportunity spent its 5th winter season in Cook Haven, a gentle swale along Murray Ridge. Two small rocks serendipitously overturned by rover wheel motions show evidence for aqueous precipitation of sulfates, and interaction with a strong oxidant (e.g., O2) to form a thin, high valence state Mn oxide coating. After the winter, Opportunity headed south to Cape Tribulation and explored Shoemaker formation impact breccias, finding numerous Ca-sulfate veins cutting across outcrops. A key target for Opportunity's measurements has been the Spirit of Saint Louis crater (SoSL), which is approximately 25 m wide, oval in plan view, shallow, flat-floored, and has a slightly raised rim. SoSL crater is surrounded by an apron of bright, polygonally-shaped outcrops and is superimposed on a gentle swale in Cape Tribulation. Rocks in a thin reddish zone on the rim are enriched in hematite, Si, and Ge, and depleted in Fe, relative to surrounding rocks. Apron rocks include an outcrop also enriched in Si and Ge, and slightly depleted in Fe. In general rocks in the crater and apron have elevated S relative to Shoemaker formation breccias, tracking values observed in the Cook Haven and the Hueytown (fracture running perpendicular to Cape Tribulation) outcrops. SoSL crater lies just to the west of Marathon Valley, a key target for exploration by Opportunity because five separate CRISM observations indicate the presence of Fe/Mg smectites on the upper valley floor. Opportunity data show that low relief, relatively bright polygonal outcrops dominate the valley floor where not covered by scree and soil shed from surrounding walls. Initial reconnaissance shows that the outcrops are breccias with compositions similar to the typical SoSL crater apron and floor rocks, although only the very upper portion of the valley has been explored as of August 2015. Pervasive but modest aqueous alteration of Endeavour's rim is implied by the combination of CRISM and Opportunity data, providing insight into early aqueous processes dominated in this location by relatively low water to rock ratios, and at least in part associated with enhanced fluid flow along fractures.

Arvidson, R. E.↗

NASA NTRS2015

Turboelectric Aircraft Drive Key Performance Parameters and Functional Requirements

The purpose of this presentation is to propose specific power and efficiency as the key performance parameters for a turboelectric aircraft power system and investigate their impact on the overall aircraft. Key functional requirements are identified that impact the power system design. Breguet range equations for a base aircraft and a turboelectric aircraft are found. The benefits and costs that may result from the turboelectric system are enumerated. A break-even analysis is conducted to find the minimum allowable electric drive specific power and efficiency that can preserve the range, initial weight, operating empty weight, and payload weight of the base aircraft.

aircraft engines↗

NASA NTRS2016

Turboelectric Aircraft Drive Key Performance Parameters and Functional Requirements

aircraft configurations↗

NASA NTRS2016

Key Elements of a Low Voltage, Ultracompact Plasma Spectrometer

Taking advantage of technological developments in wafer-scale processing over the past two decades, such as deep etching, 3-D chip stacking, and double-sided lithography, we have designed and fabricated the key elements of an ultracompact 1.5cm (exp 3)plasma spectrometer that requires only low-voltage power supplies, has no microchannel plates, and has a high aperture area to instrument volume ratio. The initial design of the instrument targets the measurement of charged particles in the 3-20keV range with a highly directional field of view and a 100 duty cycle; i.e., the entire energy range Is continuously measured. In addition to reducing mass, size, and voltage requirements, the new design will affect the manufacturing process of plasma spectrometers, enabling large quantities of identical instruments to be manufactured at low individual unit cost. Such a plasma spectrometer is ideal for heliophysics plasma investigations, particularly for small satellite and multispacecraft missions. Two key elements of the instrument have been fabricated: the collimator and the energy analyzer. An initial collimator transparency of 20 with 3deg x 3deg angular resolution was achieved. The targeted 40 collimator transparency appears readily achievable. The targeted energy analyzer scaling factor of 1875 was achieved; i.e.20 keV electrons were selected for only a 10.7V bias voltage in the energy analyzer.

Scime, E. E.↗

NASA NTRS2022

Geologically Recent Areas as One Key Target for Identifying Active Volcanism on Venus

The recently selected NASA VERITAS and DAVINCI missions, the ESA EnVision, the Roscosmos Venera-D will open a new era in the exploration of Venus. One of the key targets of the future orbiting and in-situ investigations of Venus is the identification of volcanically active areas on the planet. The study of the areas characterized by recent or ongoing volcano-tectonic activity can inform us on how volcanism and tectonism are currently evolving on Venus. Following this key target, the manuscript by Brossier et al. (2022) (https://doi.org/10.1029/2022GL099765) extends the successful approach and methodology used by previous works to Ganis Chasma in Atla Regio. We comment here on the main results of the manuscript published by Brossier et al. (2022) (https://doi.org/10.1029/2022GL099765) and discuss the important implications of their work for the future orbiting and in-situ investigations of Venus. Their results add further lines of evidence indicating possibly recent volcanism on Venus.

Solar system↗

NASA NTRSDate not supplied

Hayabusa2#’s Exploration to Asteroids 2001 CC21 and 1998 KY26 Provides Key Insights Into Planetary Defense

The Hayabusa2 extended mission, nicknamed Hayabusa2# (SHARP: Small Hazardous Asteroid Reconnaissance Probe), started its mission after the Hayabusa2 spacecraft successfully returned in December 2020 to the Earth with Ryugu's samples and released the Sample Return Capsule containing it. Hayabusa2#’s key operations include flying by Near Earth Asteroid (98943) 2001 CC21 and rendezvousing with Near-Earth Asteroid 1998 KY26. The flyby is planned to be in 2026, and the rendezvous will be in 2031. Detailed investigations of these targets enable maturing key knowledge and technologies necessary for planetary defense. This paper reviews the characteristics of these targets and strategies to maximize outcomes from the mission. The spacecraft will fly by 2001 CC21 at a speed of ~5 km/s in 2026. Given constraints on the spacecraft condition, not designed to perform a flyby operation, operational plans require careful assessments to maximize the proximity observations of this asteroid. The ~700 m diameter asteroid's shape is currently unknown, though lightcurve observations suggest the asteroid is elongated. While the spin pole is not constrained well, the spin period is about 5.02 h with uncertainties of 0.01 h [1]. The taxonomic class may be L-type, which implies the presence of Calcium-aluminum-rich inclusions (CAI), one of the primitive materials in the solar system [2], although there are studies suggesting an S-type. Therefore, this must be carefully examined. Photometric and spectroscopic observations will strongly constrain this asteroid’s properties. Our rendezvous target, 1998 KY26, is a ~30 m diameter roundish object spinning at a spin period of 10.7 min, which may represent one of the common groups of Near Earth Asteroids in size and composition that give a higher likelihood of threatening the Earth. Radar and optical observations reconstructed this asteroid's shape with high uncertainties and inferred that its surface composition might be similar to that of carbonaceous asteroids [3]. No spacecraft has ever visited such small bodies. Hayabusa2# visiting 1998 KY26 will be the first mission to document its geophysical properties, offering strong insights into what most frequent invaders look like [4].

Hayabusa2#↗

NASA NTRS2023

Protracted oxygenation across the Cambrian–Ordovician transition: A key initiator of the Great Ordovician Biodiversification Event?

Fluctuations in marine oxygen concentrations have been invoked as a primary driver for changes in biodiversity throughout Earth history. Expansions in reducing marine conditions are commonly invoked as key causal mechanisms for mass extinctions, while increases in marine oxygenation are becoming an increasingly common causal mechanism invoked for biodiversification events. Here we utilize a multiproxy approach to constrain local and global marine paleoredox conditions throughout the late Cambrian–Early Ordovician from two drill core successions in Baltoscandia. Local paleoredox proxies such as manganese concentrations and iron speciation reveal that both sites in the Baltic paleobasin had persistently anoxic and predominantly euxinic (anoxic and sulfidic) bottom water conditions throughout the study interval. Corresponding trace metal datasets indicate nuanced contraction and expansion of global anoxic and euxinic conditions along continental margins during the late Cambrian–Early Ordovician. Lastly, thallium isotope data from these locally reducing sections suggest a global expansion of oxygenated shelf and deeper marine environments from the late Cambrian into the Early Ordovician. This evidence for increasingly oxic marine environments coincides with increases in burrowing depth and tiering in marine animals, as well as diversification of body fossils throughout this ~8-million-year interval. The collective geochemical datasets provide some of the first direct paleoredox evidence for an increase in marine oxygen concentrations as a key mechanism for the Ordovician radiation of marine life

anoxia↗

DOE OSTI2024

Passive continuous variable quantum key distribution scheme using a thermal source

A passive continuous variable quantum key distribution scheme, where Alice splits the output of a thermal source into two beams, measures one locally and transmits the other mode to Bob after applying attenuation. A secure key can be established based on measurements of the two beams without the use of a random number generator or an optical modulator.

Qi, Bing↗

DOE OSTI2024

Review of Technical Photovoltaic Key Performance Indicators and the Importance of Data Quality Routines

Technical key performance indicators (KPIs) are important metrics used to assess and quantitatively summarize various aspects of photovoltaic (PV) systems, including long-term performance, economic viability, and carbon footprint. Herein, a group of experts of the International Energy Agency's Photovoltaic Power Systems Programme Task 13 collect and describ the most important technical KPIs used in the industry. Thereby, a set of best practices for reliably handling PV system data is presented and the impact of data quality and climatic variability on KPI calculation is investigated. Further, the effective use of technical KPIs allows triggering data-driven and informed decisions to optimize PV systems and providing a comprehensive overview of how PV systems operate across different conditions and climates. With the worldwide growth of the PV industry, more companies operate/own PV systems in different regions, where the climatic and seasonal profiles differ. This requires context-aware evaluation of KPIs, or the judicious application of multiple KPIs, to ensure that each asset is evaluated correctly. Beyond that, there is untapped potential in the utilization of KPIs through geospatial mapping and extrapolation of fleet KPIs. This study demonstrates that the uncertainty in KPI estimation is not well understood and depends on data quality, climatic variability, and system configuration.

14 SOLAR ENERGY↗

DOE OSTI2024

Customer-Focused Key Performance Indicators for Electric Vehicle Charging

To systematically improve the public charging experience, EV charging industry stakeholders need to define and measure it precisely. Many stakeholders currently measure aspects of the charging experience, but they typically employ metrics that are either operational in nature, such as charger uptime and mean time between failures, or composite customer satisfaction indices. To improve the customer experience most effectively, the industry needs metrics that define the charging experience from the perspective of the customer, not business operations. Furthermore, industry practitioners need granular metrics to know what specific aspects of the charging experience need improvement. This report defines such customer-focused metrics, called key performance indicators (KPIs).

33 ADVANCED PROPULSION SYSTEMS↗

DOE OSTI2025

Standardized CROAs Key Legal Provisions [Slides]

Standardized Carbon Dioxide Removal Agreements (CROA) Key Legal Provisions were compiled after the stakeholder discovery interviews and reviewing the existing contracts.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

DOE OSTI2025