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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 NTRSDate not supplied

The Radsetta Stone – Establishing a Common Environment Taxonomy Across Space Nuclear Technologies

Qualitative descriptions, such as “high temperature” or “long exposure” vary substantially according to the context and can obfuscate messaging. A quantitative taxonomy for describing space nuclear environments - encompassing fission, radioisotope, and natural - has been established to enable clear communication across technology applications. Zones have been defined to partition environments with an intent to achieve a useful level of granularity. These zones enable a more detailed assessment than the Technology Readiness Level and can also be used to identify gaps and overlaps spanning space nuclear technologies. This framework has been named the Radsetta Stone – a paronomasia of the Rosetta Stone. There are two directions in which the Radsetta Stone can be used. The user may be a technology developer or a technology customer. The developer would use the Radsetta Stone to communicate the current state of the technology they are developing. The maximum zone for each parameter would then be used to state the current limit of their technology. The customer could use the Radsetta Stone to communicate the environmental conditions of their system. Zones would be associated with different locations within the system. The Radsetta Stone is intended to enable clear communication regarding space nuclear technology. The following legend and tables show the levels of the Radsetta Stone. These levels show success criteria gates in a similar manner as Technology Readiness Levels.

taxonomy↗

NASA NTRS1993

Development of global/chemistry model for jet-fuel thermal stability based on observations from static and flowing experiments

Two global-chemistry models for oxidative deposition of jet fuels are evaluated by integrating them into a Computational Fluid Dynamics with Chemistry (CFDC) code. A previously developed two-step global-chemistry model was found to be insufficient to describe the thermal-oxidation and -deposition rates associated with a Jet-A fuel. A new global-chemistry model has been developed systematically based on observations from flowing and static experiments. The global-autoxidation reaction is modified such that the reaction rate becomes zeroth-order with respect to the dissolved oxygen concentration. The generation of deposit-forming precursor is coupled with the autoxidation reaction by introducing a radical species ROO. A formulation for the sticking probability has also been developed. Deposition profiles are well represented by this new model under a variety of temperature and flow conditions. The model correctly predicts the changes in magnitude and spatial location of the deposition peak due to changes in flow. The CFDC model, which is designed for flowing systems, has been extended to static experiments. The model incorporates a non-depleting species F(sub s) representing all non-oxygen compounds responsible for deposition. Static experiments were found to provide a useful and inexpensive method for estimating the concentration of F(sub s) in the fuel.

V. R. Katta↗

NASA NTRSDate not supplied

NASA’s SLS (Space Launch System) Rocket Ready for Artemis II Lunar Mission

In early 2026, NASA will launch the Artemis II mission, an approximately 10-day long lunar mission that will fly three NASA astronauts and one CSA (Canadian Space Agency) astronaut on a free-return trajectory around the Moon, following a one-day checkout of their Orion spacecraft in Earth orbit. The mission will be the first to launch astronauts aboard NASA’s Orion spacecraft and on top of the agency’s SLS (Space Launch System) rocket. The mission will also deploy four 12U CubeSats as secondary payloads from the Orion stage adapter, following Orion separation and departure. The payloads, developed by four of NASA’s international partners, will perform a variety of science and technology investigations. The SLS and Orion for the mission are currently stacked in the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center in Florida and are undergoing final preparations to rollout to Launch Pad 39B for a tanking test before launch. In addition to preparations for the Artemis II mission, significant progress is being made on the SLS for the Artemis III mission, which is targeted to return astronauts to the lunar surface no later than 2029. Major components of the core stage and solid rocket boosters are already at NASA Kennedy undergoing build-up for the mission. Data from the Artemis II launch and mission, as well as progress to subsequent missions, as available, will be presented.

Bruce R Askins↗

NASA NTRS1994

Surface Characterization Through Shape Oscillations of Drops in Microgravity and 1-g

The goal of these experiments is to determine the rheological properties of liquid drops of single or multiple components in the presence or absence of surface active materials by exciting drops into their quadrupole resonance and observing their free decay. The resulting data coupled with appropriate theory should give a better description of the physics of the underlying phenomena, providing a better foundation than earlier empirical results could. The space environment makes an idealized geometry available (spherical drops) so that theory and experiment can be properly compared, and allows a 'clean' environment, by which is meant an environment in which no solid surfaces come in contact with the drops during the test period. Moreover, by considering the oscillations of intentionally deformed drops in microgravity, a baseline is established for interpreting surface characterization experiments done on the ground by other groups and ours. Experiments performed on the United States Microgravity Laboratory Laboratory (USML-1) demonstrated that shape oscillation experiments could be performed over a wide parameter range, and with a variety of surfactant materials. Results, however, were compromised by an unexpected, slow drop tumbling, some problems with droplet injection, and the presence of bubbles in the drop samples. Nevertheless, initial data suggests that the space environment will be useful in providing baseline data that can serve to validate theory and permit quantitative materials characterization at 1-g.

Robert E Apfel↗

NASA NTRS1974

Skylab M551 Metals Melting Experiment

The objectives of the M551 Metals Melting Experiment are to (a) study behavior of molten metal, (b) characterize metals melted and solidified in the low gravity space environment compared to one-gravity of earth, and (c) determine feasibility of joining metals in space. The experiment used the electron beam (EB) and chamber of the M512 apparatus to make a dwell puddle and a melt in a rotating disc of varying thickness. Hence, the EB performed cut-through, full and partial penetration melts, in addition to a re-solidified button. The three disc materials were aluminum 2219-T87, 304 stainless steel and pure tantalum to provide a wide range of density and melting conditions. Observations to date include (a) the proof that EB welding, cutting and melting can be done successfully in low gravity. Earlier, some welding authorities had postulated that without gravity the EB would force the molten puddle out of contact. However, the experiment proved that surface tension forces predominate. (b) From the view-point of cast-solidification, small, equiaxed grains in Skylab specimens compared to large, elongated grains in ground-based specimens were observed. The former are thought to be associated with constitutional supercooling and nucleation where the latter are associated with dendritic solidification. In further support of the more equiaxed grain growth in Skylab, symmetric sub-grain patterns were frequently observed where there was much less symmetry in ground-based specimens. Further work is being done to explain the differences in solidification.

E C Mckannan↗

NASA NTRS2026

Ultrasonic Washer–Dryer System for Space Habitats: Design Upgrades and Parabolic Flight Readiness

Clothing makes up nearly 25% of all non-food supplies sent to the International Space Station (ISS). To support sustainable human missions in deep space, NASA’s Life Support and Habitation Systems Focus Area looks to advance technologies to support and improve logistics. Our team is creating a compact ultrasonic clothing washer/dryer system that bypasses traditional limitations and is suitable for space. Thermal drying uses a lot of energy to evaporate water, while our ultrasonic drying method offers a quicker, more efficient alternative. It uses piezoelectric transducers to vibrate textiles at the micron scale, mechanically removing water as cold mist rather than evaporating it. This speeds up drying and reduces energy use, no matter the fabric makeup. This paper details recent upgrades to a full-scale ultrasonic washer–dryer system, readying it for parabolic flight testing. Improvements include an enhanced human–machine interface, better packaging, and optimized performance and control. We also present extensive pre-flight ground tests conducted to ensure reliability and identify potential risks. Collaborating with P&G, we report preliminary cleaning tests using various detergents. These results lay a crucial foundation for the laundry system designed specifically for space. By cutting clothing-related payload and waste by over 97%, this technology supports long-term human exploration missions on the ISS, the Moon, Mars, and beyond.

Ultrasonic↗

NASA NTRSDate not supplied

A Simplified Model of VIPER Thermal Management System. Part I: Loop Heat Pipe

NASA’s Volatiles Investigating Polar Exploration Rover (VIPER) uses a combination of loop heat pipes (LHPs) and heaters as the primary hardware to modulate the temperature of the electronic boxes and payloads instruments. LHPs have been designed and instrumented to be capable of passive and active shutdown. The goal of the passive shutdown, using a thermal control valve (TCV) to limit the flow of the working fluid, is to preserve thermal energy and avoid unnecessary heat leaks during lunar night. The goal of the active shutdown on the other hand, is to forcefully increase the vehicle internal temperature to bakeout the payload instruments. Several numerical modeling tools are available to analyze LHP performance under the complex set of operational requirements and environments levied on the VIPER Thermal Management System (TMS). Yet, while those numerical modeling tools are capable of detailed performance analysis, they tend to take large computational resources and long computational time. In this paper, a model of a single LHP developed based on control volume approach is presented. By using the control volume approach, the complex geometry of the LHP, and the components attached to it, are reduced to thermal lump capacitances, thus reducing the computation effort. This paper also describes the effort to correlate the proposed LHP model using thermal vacuum (TVAC) test data.

Loop Heat Pipe↗

NASA NTRSDate not supplied

A Simplified Model of VIPER Thermal Management System. Part I: Loop Heat Pipe

Loop Heat Pipe↗

NASA NTRS1964

Radio Noise Problems in Arctic Regions

Three main types of radio noise should be considered when establishing noise levels for communication purposes or in experiments utilizing radio techniques in Arctic regions. These are atmospheric and man-made noise, and precipitation static. National Bureau of Standards radio noise data obtained hourly at Arctic and Antarctic stations on eight .fixed frequencies between 51 kc and 20 Mc/s are analyzed to show the characteristics of the three types. The diurnal and seasonal variations of atmospheric radio noise at high latitudes are explainable in terms of changes in propagation factors and in the distribution of world thunderstorm activity. In both northern and southern Arctic regions atmospheric noise decreases during polar cap absorption (PCA), most markedly in the h.f. band. The probable magnitude of man-made noise in the h.f. band is estimated from data taken during PCA, when atmospheric noise is absent. At Thule man-made noise on 2.5 and 5 Mc/s appears to be 57 and 49 dB above kTB (where kTB is antenna thermal noise power), respectively, while at Byrd Station the values are about 20 and 12 dB respectively. Precipitation static is generated on exposed antennas during periods of blowing snow (blizzards). The noise power magnitude can be at least 50 dB above man-made and atmospheric levels, but the maximum enhancement cannot be ascertained because of missing data. In winter and spring months at Byrd Station radio data dependent upon exposed antennas may be lost 10-30 per cent of the time due to precipitation static alone.

Radio Noise↗

NASA NTRSDate not supplied

Stationary Testing of a Pulse Tube Cryocooler Designed to Rotate at 6800 RPM with the Superconducting Rotor of an Electric Machine

Electrified aircraft are being developed to increase the efficiency and reduce the cost of operating subsonic transport aircraft. Achieving a substantial impact necessitates focusing on single- and twin-aisle aircraft which use propulsion systems with >20 MW ratings. For these aircraft, multi-MW superconducting electric machines are being developed due to their high specific power and high efficiency. Most of these electric machines employ superconductors on their rotor, thereby requiring cryogenic cooling of the rotating system. An attractive solution is to conductively cool the rotor using a cryocooler that rotates with the rotor. NASA has been developing a 50 K pulse tube cryocooler for its High Efficiency Megawatt Motor (HEMM) that can operate while rotating at up to 6,800 rpm. The first non-rotating tests of the fully assembled HEMM cryocooler have been completed, and initial testing has yielded a no-load temperature of 112 K. A small helium leak into the vacuum system has been identified as the major bottleneck to performance, and based on measurements with the motor turned off there is an observed vacuum-side heat leak of approximately 30 W at 115 K. Immediate next steps for testing are to locate and mitigate the apparent helium leaks into the vacuum chamber. Thus far, compressor performance and the apparent heat lift after correcting for the heat leak are on par with expectations.

Electrified Aircraft Propulsion↗

NASA NTRS1996

Planetary and Deep Space Requirements for Photovoltaic Solar Arrays

In the past 25 years, the majority of interplanetary spacecraft have been powered by nuclear sources. However, as the emphasis on smaller, low cost missions gains momentum, more deep space missions now being planned have baselined photovoltaic solar arrays due to the low power requirements (usually significantly less than 100 W) needed for engineering and science payloads. This will present challenges to the solar array builders, inasmuch as planetary requirements usually differ from earth orbital requirements. In addition, these requirements often differ greatly, depending on the specific mission; for example, inner planets vs. outer planets, orbiters vs. flybys, spacecraft vs. landers, and so on. Also, the likelihood of electric propulsion missions will influence the requirements placed on solar array developers. This paper will discuss representative requirements for a range of planetary and deep space science missions now in the planning stages. We have divided the requirements into three categories: Inner planets and the sun; outer planets (greater than 3 AU); and Mars, cometary, and asteroid landers and probes. Requirements for Mercury and Ganymede landers will be covered in the Inner and Outer Planets sections with their respective orbiters. We will also discuss special requirements associated with solar electric propulsion (SEP). New technology developments will be needed to meet the demanding environments presented by these future applications as many of the technologies envisioned have not yet been demonstrated. In addition, new technologies that will be needed reside not only in the photovoltaic solar array, but also in other spacecraft systems that are key to operating the spacecraft reliably with the photovoltaics.

C P Bankston↗

NASA NTRS1994

Protein Crystal Growth Results From the United States Microgravity Laboratory-1 Mission

Protein crystal growth experiments have been performed by this laboratory on 18 Space Shuttle missions since April, 1985. In addition, a number of microgravity experiments also have been performed and reported by other investigators. These Space Shuttle missions have been used to grow crystals of a variety of proteins using vapor diffusion, liquid diffusion, and temperature-induced crystallization techniques. The United States Microgravity Laboratory - 1 mission (USML-1, June 25 - July 9, 1992) was a Spacelab mission dedicated to experiments involved in materials processing. New protein crystal growth hardware was developed to allow in orbit examination of initial crystal growth results, the knowledge from which was used on subsequent days to prepare new crystal growth experiments. In addition, new seeding hardware and techniques were tested as well as techniques that would prepare crystals for analysis by x-ray diffraction, a capability projected for the planned Space Station. Hardware that was specifically developed for the USML-1 mission will be discussed along with the experimental results from this mission.

L J Delucas↗

NASA NTRS2008

Characterization of a New Phase and Its Effect on the Work Characteristics of a Near-Stoichiometric Ni30Pt20Ti50 High-Temperature Shape Memory Alloy (HTSMA)

A new phase observed in a nominal Ni 30 Pt 20 Ti 50 (at.%) high temperature shape memory alloy has been characterized using transmission electron microscopy and 3-D atom probe tomography. This phase forms homogenously in the B2 austenite matrix by a nucleation and growth mechanism and results in a concomitant increase in the martensitic transformation temperature of the base alloy. Although the structure of this phase typically contains a high density of faults making characterization difficult, it appears to be trigonal (-3m point group) with a o ~1.28 nm and c o ~1.4 nm. Precipitation of this phase increases the microhardness of the alloy substantially over that of the solution treated and quenched single-phase material. The effect of precipitation strengthening on the work characteristics of the alloy has been explored through load-biased strain-temperature testing in the solution-treated condition and after aging at 500 ºC for times ranging from 1 to 256 hours. Work output was found to increase in the aged alloy as a result of an increase in transformation strain, but was not very sensitive to aging time. The amount of permanent deformation that occurred during thermal cycling under load was small but increased with increasing aging time and stress. Nevertheless, the dimensional stability of the alloy at short aging times (1-4 hours) was still very good making it a potentially useful material for high-temperature actuator applications.

A Garg↗

NASA NTRS2019

Rewet Temperature Correlations for Liquid-Nitrogen Boiling Pipe Flows Across Varying Flow Conditions and Orientations

In many convective liquid-vapor phase change heat transfer engineering applications, cryogenic fluids are widely used in industrial processes, spacecraft and cryosurgery systems, and so on. For example, cryogens are usually used as liquid fuels such as liquid hydrogen and oxygen in the rocket industry, liquid nitrogen (LN2) and helium are frequently used to cool superconducting magnetic device for medical applications. In these systems, proper transport, handling, and storage of cryogenic fluids are of extreme importance. Among all the cryogenic transport processes performed in room temperatures, quenching, also termed chilldown, is a unavoidable initial, transient phase-change heat transfer process that brings the system down to the cryogenic condition. The Leidenfrost temperature or rewet temperature that signals the end of film boiling is practically considered the completion point of a quenching process. Therefore, rewet temperature has been considered the most important parameter for the engineering design of cryogenic thermal management systems. As most of the previous correlations for predicting the Leidenfrost temperature and the rewet temperature have been basically developed for water, they are shown to disagree with recent liquid nitrogen pipe chilldown experiments in upward and downward flow directions over a wide range of flow rates, pressures, and degrees of inlet subcooling. In addition to a complete review of the literature, two new correlations are presented in this work, one based on bubble growth and another based on the theoretical maximum limit of superheat. Each correlation performs well over the entire data set.

liquid nitrogen↗

NASA NTRSDate not supplied

A Simplified Model of VIPER Thermal Management System. Part II: Integrated Vehicle

NASA’s Volatiles Investigating Polar Exploration Rover (VIPER) thermal management system (TMS) relies on four loop heat pipes (LHPs) to transport electronic waste heat to the vehicle cooling radiative surface and avoid overheating. The TMS has also ten constant conductance heat pipes (CCHPs) dedicated to balance the thermal load within the internal environment where the avionics boxes are mounted, also called warm electronic box (WEB), and to transport the heat from two of the science payload instruments. The TMS also uses two thermal straps to thermally link the batteries to the WEB. These thermal components, in addition to heaters, thermostat, multi-layer insulation (MLIs), and isolators forms the core of the VIPER TMS. The complex heat transport balance managed by the TMS is challenging to characterize and model. The more fidelity and granularity of a model, the more costly the computational resources needed and the longer the simulation and modeling time. When the priority is to provide quick but reliable assessments of the thermal performance or real time thermal feedback for training of console operators, simplified modeling tools are needed. To satisfy that need, this paper describes the effort to develop and correlate a model of VIPER TMS based on control volume approach. The correlation effort in particular focuses on hibernation, cold thermal balance, and hot thermal balance data from the integrated vehicle thermal vacuum (TVAC) test. Thus, the correlated model captures the heat leaks during hibernations and the performance at two extremes, bounding, operating scenarios.

Loop Heat Pipe↗

NASA NTRSDate not supplied

A Simplified Model of VIPER Thermal Management System. Part II: Integrated Vehicle

Thermal Modeling↗

NASA NTRS1977

Lunar Electrical Conductivity, Permeability and Temperature From Apollo Magnetometer Experiments

Magnetometers have been deployed at four Apollo sites on the Moon to measure remanent and induced lunar magnetic fields. Measurements from this network of instruments have been used to calculate the electrical conductivity, temperature, magnetic permeability, and iron abundance of the lunar interior. The measured lunar remanent fields range from 3 gammas (γ) minimum at the Apollo 15 site to 327 γ maximum at the Apollo 16 site. Simultaneous magnetic field and solar plasma pressure measurements show that the remanent fields at the Apollo 12 and 16 sites interact with, and are compressed by, the solar wind. Remanent fields at Apollo 12 and Apollo 16 are increased 16 γ and 32 γ, respectively, by a solar plasma bulk pressure increase of 1.5 x 10 -7 dynes/cm 2 . Global lunar fields due to eddy currents, induced in the lunar interior by magnetic transients, have been analyzed to calculate an electrical conductivity profile for the Moon. From nightside magnetometer data in the solar wind it has been found that deeper than 170 km into the Moon the conductivity rises from 3 x 10 -4 mhos/m to 10 -2 mhos/m at 1000-km depth. Recent analysis of data obtained in the geomagnetic tail, in regions free of complicating plasma effects, yields results consistent with nightside values. Conductivity profiles have been used to calculate the lunar temperature for an assumed lunar material of olivine. In the outer layer (~ 170 km thick) the temperature rises to 110° C, after which it gradually increases with depth to 1500° C at a depth of ~ 1000 km. Simultaneous measurements by magnetometers on the lunar surface and in orbit around the moon are used to construct a whole-moon hysteresis curve, from which the global lunar magnetic permeability is determined to be μ = 1.012 ± 0.006. The corresponding global induced dipole moment is 2 x 10 18 gauss-cm 3 for typical inducing fields of 10 -4 gauss in the lunar environment. Lunar free iron abundance corresponding to the global permeability is determined to be 2.5 ± 2.0 wt. %. Total iron abundance (sum of iron in the ferromagnetic and paramagnetic states) is calculated for two assumed compositional models of the lunar interior. For a free iron/orthopyroxene lunar composition the total iron content is calculated to be 12.8 ± 1.0 wt. %; for a free iron/olivine composition, total iron content is 5.5 ± 1.2 wt. %. Other lunar models with an iron core and with a shallow iron-rich layer are also discussed in light of the measured global lunar permeability. Velocities and thicknesses of the Earth's magnetopause and bow shock have been estimated from simultaneous magnetometer measurements. Average speeds are determined to be about 50 km/s for the magnetopause and 70 km/s for the bow shock, although there are large variations in the measurement for any particular boundary crossing. Corresponding measured boundary thicknesses average about 2300 km for the magnetopause and 1400 km for the bow shock.

P Dyal↗

NASA NTRS2026

Atacama Cosmology Telescope A Measurement of Galaxy Cluster Temperatures Through Relativistic Corrections to the Thermal Sunyaev-Zeldovich Effect

The high electron temperature in galaxy clusters (> 1 keV or > 107 K) leads to corrections at the level of a few percent in their thermal Sunyaev-Zeldovich effect signatures. Both the size and frequency dependence of these corrections, which are known as relativistic temperature corrections, depend upon the temperature of the objects. In this work we exploit this effect to measure the average temperature of a stack of Compton-y selected clusters. Specifically, we apply the “spectroscopic method” and search for the temperature that best fits the clusters’ signal measured at frequencies from 30 to 545 GHz by the Atacama Cosmology Telescope and Planck satellite. We measure the average temperature of clusters detected in the Atacama Cosmology Telescope maps to be 8.5 2.4 keV, with an additional systematic error of comparable amplitude dominated by passband uncertainty. Upcoming surveys, such as the Simons Observatory and CMB-S4, have the potential to dramatically improve upon these measurements and thereby enable precision studies of cluster temperatures with millimeter observations. The key challenge for future observations will be mitigating instrumental systematic effects, which already limit this analysis.

William R Coulton↗