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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 NTRS2006

NASA's Spitzer Space Telescope's Operational Mission Experience

New Generation of Detector Arrays(100 to 10,000 Gain in Capability over Previous Infrared Space Missions). IRAC: 256 x 256 pixel arrays operating at 3.6 microns, 4.5 microns, 5.8 microns, 8.0 microns. MIPS: Photometer with 3 sets of arrays operating at 24 microns, 70 microns and 160 microns. 128 x 128; 32 x 32 and 2 x 20 arrays. Spectrometer with 50-100 micron capabilities. IRS: 4 Array (128x128 pixel) Spectrograph, 4 -40 microns. Warm Launch Architecture: All other Infrared Missions launched with both the telescope and scientific instrument payload within the cryostat or Dewar. Passive cooling used to cool outer shell to approx.40 K. Cryogenic Boil-off then cools telescope to required 5.5K. Earth Trailing Heliocentric Orbit: Increased observing efficiency, simplification of observation planning, removes earth as heat source.

space telescopes↗

NASA NTRS1975

Lightweight fuel cell powerplant for Tug

The design and characteristics of a lightweight powerplant based on advanced cell technology to meet the requirements of the Space Tug are described. The powerplant can be operated off low-pressure hydrogen and oxygen rocket propellant tanks and avoid the need for a dedicated reactant supply. Product water can be condensed or not, depending on vehicle or payload requirements. The heart of the unit, the fuel cell power section, consist of lightweight, series-connected, alkaline cells, while the power section contains accessory components for reactant conditioning, distribution, and venting, coolant circulation, passive product water removal and electric control. The proposed design offers at least a 50 per cent saving in powerplant weight, so that the total estimated powerplant dry weight including structure, tubing, wiring, interface connectors, and interface heat exchanger is 48 lb.

Handley, L. M.↗

NASA NTRS2011

Characterization Testing of the Teledyne Passive Breadboard Fuel Cell Powerplant

NASA's Exploration Technology Development Program (ETDP) is tasked with the development of enabling and enhancing technologies for NASA's exploration missions. As part of that initiative, the return to the Moon requires a reliable, efficient, and lightweight fuel cell powerplant system to provide power to the Altair Lunar Lander and for lunar surface systems. Fuel cell powerplants are made up of two basic parts; the fuel cell itself and the supporting ancillary subsystem. This subsystem is designed to deliver reactants to the fuel cell and remove product water and waste heat from the fuel cell. Typically, fuel cell powerplant ancillary subsystems rely upon pumps and active water separation techniques to accomplish these tasks for closed hydrogen/oxygen systems. In a typical system, these components are the largest contributors to the overall parasitic power load of the fuel cell powerplant. A potential step towards the development of an efficient lightweight power system is to maximize the use of "passive" or low-power ancillary components as a replacement to these high-power load components

Loyselle, Patricia↗

NASA NTRS2016

Combining Passive Thermography and Acoustic Emission for Large Area Fatigue Damage Growth Assessment of a Composite Structure

Passive thermography and acoustic emission data were obtained for improved real time damage detection during fatigue loading. A strong positive correlation was demonstrated between acoustic energy event location and thermal heating, especially if the structure under load was nearing ultimate failure. An image processing routine was developed to map the acoustic emission data onto the thermal imagery. This required removing optical barrel distortion and angular rotation from the thermal data. The acoustic emission data were then mapped onto thermal data, revealing the cluster of acoustic emission event locations around the thermal signatures of interest. By combining both techniques, progression of damage growth is confirmed and areas of failure are identified. This technology provides improved real time inspections of advanced composite structures during fatigue testing.Keywords: Thermal nondestructive evaluation, fatigue damage detection, aerospace composite inspection, acoustic emission, passive thermography

Zalameda, Joseph N.↗

NASA NTRS2012

Loop Heat Pipe with Thermal Control Valve as a Variable Thermal Link

Future lunar landers and rovers will require variable thermal links that allow for heat rejection during the lunar daytime and passively prevent heat rejection during the lunar night. During the lunar day, the thermal management system must reject the waste heat from the electronics and batteries to maintain them below the maximum acceptable temperature. During the lunar night, the heat rejection system must either be shut down or significant amounts of guard heat must be added to keep the electronics and batteries above the minimum acceptable temperature. Since guard heater power is unfavorable because it adds to system size and complexity, a variable thermal link is preferred to limit heat removal from the electronics and batteries during the long lunar night. Conventional loop heat pipes (LHPs) can provide the required variable thermal conductance, but they still consume electrical power to shut down the heat transfer. This innovation adds a thermal control valve (TCV) and a bypass line to a conventional LHP that proportionally allows vapor to flow back into the compensation chamber of the LHP. The addition of this valve can achieve completely passive thermal control of the LHP, eliminating the need for guard heaters and complex controls.

Hartenstine, John↗

NASA NTRSDate not supplied

Bench Scale Heat Pipe and Vapor Chamber Testing for Space Applications

NASA’s space missions demand better and more efficient carbon dioxide removal systems. wo challenges present themselves in improving the state of the art pellet adsorption beds: power minimization and uniform heating for carbon dioxide desorption. Titanium heat pipes and vapor chambers were found to be excellent candidates in solving these problems because of their passive heating nature, tolerance to high temperatures, and capability of direct implementation into these adsorbent beds.This research work compares these different titanium heat pipes (HPs) and vapor chambers (VPs).

MultiSORB↗

NASA NTRS2019

Thermal design and on-orbit performance of the ECOSTRESS instrument

The ECOSystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) instrument, launched on June 29, 2018, has completed nine months of operation in space. ECOSTRESS is a multispectral thermal infrared imaging radiometer and its primary mission is to investigate and understand how climate change affects water and carbon usage on Earth. The thermal control subsystem consists of a combination of active and passive components to maintain instrument components within the allowable flight temperature limits. Its focal plane detector is cooled to 65K by a pair of mechanical cryocoolers and a third mechanical cryocooler cools an intermediate cold shield to 130K. The heat dissipation generated by cryocoolers and electronics, is removed through non-planar cold plates and tube-on plate heat exchanger, which are cooled by a circulating fluid -EF module. The heat collected by the JEM-EF fluid is exchanged with a fluid loop that circulates through radiators located on the exterior of the Space Station. This paper provides an overview of the thermal and cryogenic system design, thermal analysis results and reviews the on-orbit thermal performance.

Romero, M.↗

NASA NTRS2021

Effect of Reactant Pressure on Proton Exchange Membrane Fuel Cell Performance

It is an objective of the National Aeronautics and Space Administration (NASA) to return to the moon and to create sustained lunar operations. Since many applicable lander and upper stage vehicles utilize cryogenic hydrogen and oxygen propellants, it is appealing to incorporate fuel cells into potential mission concepts. A fuel cell could generate electricity, heat, and water from the residual hydrogen and oxygen propellants. Such a concept depends on the capability of the fuel cell to utilize dry, propellant-grade reactants at reduced pressures compared to typical fuel cell operating conditions. This report describes a NASA evaluation of two passive water removal, non-flow-through proton exchange membrane (PEM) fuel cells: a twelve-cell 50 sq. cm active area stack and a seven-cell 150 sq. cm active area stack. Both stacks operated on research grade hydrogen and oxygen reactants supplied at pressures ranging from 20 psia up to the 45-48 psia design operating point, reliably supporting current densities of at least 450 mA/sq. cm at reduced pressures. Polarization curves, fitted with a semi-empirical equation for overpotential, show an increase in effective ohmic resistance and decrease in reversible cell potential, hydrogen crossover current, and Tafel slope when operating at lower pressures, resulting in a reduction in cell voltage at all current densities. Fitted parameters are compared to published values and rationalized with first principles explanations.

fuel cells↗

NASA NTRS2019

Microgravity Liquid-Gas Two-Phase Flow: Review of Pressure Drop and Heat Transfer Correlations and Guidelines for Equipment Operability

In this report we have catalogued the flow regimes observed in microgravity, summarized correlations for the pressure drop and rate of heat transfer that are commonly used, and discuss the validation of a few correlations from available experimental results. Two-phase flow through some specific components such as bends, tees, filters and pumps are discussed from a physical perspective to guide the designer on how reduced gravity might affect their performance. Phase separation in zero gravity is addressed through the behavior and basic design concepts for devices based on passive centrifugal action, capillary forces, gas extraction through a membrane installed in a channel wall and the use of a syringe with a perforated piston to remove bubbles from small liquid volumes. We address the common instabilities that develop in flow loops owing exclusively to the two-phase nature of the flow, e.g., Ledinegg instability and concentration waves. Finally we briefly review flow metering and gauging; two-phase flow through porous media, where pressure drop and flow regime map correlations in zero-g are a current research topic; and basic operation principles of heat pipes and capillary pumped loops.

liquid-gas↗

NASA NTRS2013

Hydrogen-Enhanced Lunar Oxygen Extraction and Storage Using Only Solar Power

The innovation consists of a thermodynamic system for extracting in situ oxygen vapor from lunar regolith using a solar photovoltaic power source in a reactor, a method for thermally insulating the reactor, a method for protecting the reactor internal components from oxidation by the extracted oxygen, a method for removing unwanted chemical species produced in the reactor from the oxygen vapor, a method for passively storing the oxygen, and a method for releasing high-purity oxygen from storage for lunar use. Lunar oxygen exists in various types of minerals, mostly silicates. The energy required to extract the oxygen from the minerals is 30 to 60 MJ/kg O. Using simple heating, the extraction rate depends on temperature. The minimum temperature is approximately 2,500 K, which is at the upper end of available oven temperatures. The oxygen is released from storage in a purified state, as needed, especially if for human consumption. This method extracts oxygen from regolith by treating the problem as a closed batch cycle system. The innovation works equally well in Earth or Lunar gravity fields, at low partial pressure of oxygen, and makes use of in situ regolith for system insulation. The innovation extracts oxygen from lunar regolith using a method similar to vacuum pyrolysis, but with hydrogen cover gas added stoichiometrically to react with the oxygen as it is produced by radiatively heating regolith to 2,500 K. The hydrogen flows over and through the heating element (HE), protecting it from released oxygen. The H2 O2 heat of reaction is regeneratively recovered to assist the heating process. Lunar regolith is loaded into a large-diameter, low-height pancake reactor powered by photovoltaic cells. The reactor lid contains a 2,500 K HE that radiates downward onto the regolith to heat it and extract oxygen, and is shielded above by a multi-layer tungsten radiation shield. Hydrogen cover gas percolates through the perforated tungsten shielding and HE, preventing oxidation of the shielding and HE, and reacting with the oxygen to form water vapor. The water vapor is filtered through solid regolith to remove unwanted extraction byproducts, and then condensed to a liquid state and stored at 300 to 325 K. Conversion to usable oxygen is achieved by pumping liquid water into a high-pressure electrolyzer, storing the gaseous oxygen at high pressure for use, and diverting the hydrogen back to the reactor or to storage. The results from this design effort show that this oxygen-generating concept can be developed in an efficient system with low specific mass. Advantages include use of regolith as an oxygen source, filter, and thermal insulator. The system can be tested in Earth gravity and can be expected to operate similarly in lunar gravity. The system is scalable, either by increasing the power level and output of a standard module, or by employing multiple modules.

Burton, rodney↗

NASA NTRS2003

An Improved Design for Air Removal from Aerospace Fluid Loop Coolant Systems

Aerospace applications with requirements for large capacity heat removal (launch vehicles, platforms, payloads, etc.) typically utilize a liquid coolant fluid as a transport media to increase efficiency and flexibility in the vehicle design. An issue with these systems however, is susceptibility to the presence of noncondensable gas (NCG) or air. The presence of air in a coolant loop can have numerous negative consequences, including loss of centrifugal pump prime, interference with sensor readings, inhibition of heat transfer, and coolant blockage to remote systems. Hardware ground processing to remove this air is also cumbersome and time consuming which continuously drives recurring costs. Current systems for maintaining the system free of air are tailored and have demonstrated only moderate success. An obvious solution to these problems is the development and advancement of a passive gas removal device, or gas trap, that would be installed in the flight cooling system simplifying the initial coolant fill procedure and also maintaining the system during operations. The proposed device would utilize commercially available membranes thus increasing reliability and reducing cost while also addressing both current and anticipated applications. In addition, it maintains current pressure drop, water loss, and size restrictions while increasing tolerance for pressure increases due to gas build-up in the trap.

Ritchie, Stephen M. C.↗

NASA NTRS2024

Making Rocket Fuel from Moon Rocks: Silicon-Liquid Oxygen (SiLOX) as a Hybrid Propellant

The research team at KSC explored the controlled passivation and burning of Lunar soil constituents in an oxygen combustion vessel for use as an in-space resource. Technologies such as carbothermal reduction (CaRD) and molten regolith electrolysis (MRE) are being developed to remove the oxygen for use and leave constituents in an enriched state. This leaves behind reduced compounds that can react with oxygen for heat generation. The team at KSC looked to explore the feasibility of controlling such reactions in a pure oxygen environment for potential technology integrations. Our proof-of-concept demonstrations have given promise to many potential applications for the controlled burning or combustion of nano- and porous silicon for silicon based, Lunar economy applications. The team at KSC was able to control the burn rate and total energy released effectively via pre-treatment of the nano-silicon in a muffle furnace at varying temperatures at one-hour durations. We created a new capability at KSC with the supporting safety documentation and procedural writeup. Our work highlights the need for greater investigation to understand the regenerative properties of the proposed porous silicon discs, and its viability of a thermal and electrical energy source. This work has demonstrated the proof-of-concept that elemental silicon is able to be combusted with gaseous and liquid oxygen in a controlled manner. This report provides such evidence as well as theoretical calculations and assumptions made for technologies that would be useful in Lunar surface operations with in-situ resources. The concepts are based on the assumption that oxygen extraction technologies from Lunar regolith processing will result in enriched silicon that may be adapted for the presented use cases. Additionally, the energy storage concept is able to be adapted for terrestrial use and integrated into already existing infrastructure.

Kenneth Engeling↗

NASA NTRSDate not supplied

Lunar Passive Fuel Cell Technologies: Evaporator + Fluid Polishing Elements

This project investigates key elements of a fully-passive, fuel-cell based, surface power generation concept. The overall concept replaces the actively pumped thermal management of a state of the art (SOA) fuel cell/electrolyzer stack with a passive 2-phase thermosyphon for heat transport and a passive shape memory actuating radiator for temperature management. The elements of the concept investigated in this project are: Evaporator Element: Evaluating the compatibility of common fuel-cell interconnect materials in the evaporator of a 2-phase water thermosyphon Fluid Polishing element: The use of membrane gas separation and resin water polishing to address non-condensable gas removal and water purity.

Fuel Cell↗

NASA NTRS2015

Thirsty Walls: A New Paradigm for Air Revitalization in Life Support

Carbon Dioxide removal systems on submarines are compact and reliable. They use solubility chemistry. They spray a Carbon Dioxide adsorbing chemical directly into the air stream, and allow the liquid to settle. Carbon Dioxide removal systems on ISS are large and need repair. They use adsorption chemistry. They force air through a bed packed with granular zeolite, and heat the bed to desorb the Carbon Dioxide. The thermal cycles cause the zeolite to dust. New advances in additive manufacturing, and a better understanding of uid behavior in microgravity make it possible to expose a liquid directly to air in a microgravity environment. It is now practical to use submarine style solubility chemistry for atmosphere revitalization in space. It is now possible to develop space systems that achieve submarine levels of reliability. New developments in Ionic Liquid research make it possible to match the solubility performance characteristics of MEA used on submarines - with Ionic Liquids that do not release chemical vapors into the air. "Thirsty Walls" provide gentle, passive contact between ventilation air and Air Revitalization functions of temperature control, relative humidity control, and Carbon Dioxide removal. "Thirsty Walls" eliminates the need of large blowers and compressors that need to force air at high velocities through restrictive Air Revitalization hardware.

Graf, John↗

NASA NTRS2016

Demonstration of Nautilus Centripetal Capillary Condenser Technology

This paper describes the results of a proof of concept effort for development of a Nautilus Centripetal Capillary Condenser (NCCC or NC3) used for microgravity compatible water recovery from moist air with integral passive phase separation. Removal of liquid condensate from the air stream exiting a condenser is readily performed here on Earth. In order to perform this function in space however, without gravity or mechanical action, other tactics including utilization of inertial, drag and capillary forces are required. Within the NC3, liquid water forms via condensation on cold condenser surfaces as humid air passes along multiple spiral channels, each in its own plane, all together forming a stacked plate assembly. Non-mechanical inertial forces are employed to transfer condensate, as it forms, via centripetal action to the outer perimeter of each channel. A V-shaped groove, constructed on this outer edge of the spiral channel, increases local capillary forces thereby retaining the liquid. Air drag then pulls the liquid along to a collection region near the center of the device. Dry air produced by each parallel spiral channel is combined in a common orthogonal, out-of-plane conduit passing down the axial center of the stacked device. Similarly, the parallel condensate streams are combined and removed from the condenser/separator through yet another out-of-plane axial conduit. NC3 is an integration of conventional finned condenser operation, combined with static phase separation and capillary transport phenomena. A Mars' transit mission would be a logical application for this technology where gravity is absent and the use of vibrating, energy-intensive, motor-driven centrifugal separators is undesired. Here a vapor stream from either the Heat Melt Compactor or the Carbon dioxide Reduction Assembly, for example, would be dried to a dew point of 10 deg using a passive NC3 condenser/separator with the precious water condensate recycled to the water bus.

Separator↗

NASA NTRS1980

Active heat exchange system development for latent heat thermal energy storage

Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application. Two concepts selected for hardware development are a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which has been nickel plated to decrease adhesion forces. Suitable phase change material (PCM) storage media with melting points in the temperature range of interest (250 C to 400 C) were investigated. The specific salt recommended for laboratory tests was a chloride eutectic (20.5KCl-24/5 NaCl-55.0MgCl 2% by wt.), with a nominal melting point of 385 C.

Alario, J.↗

NASA NTRS1979

Tests of a protective shell passive release mechanism for hypersonic wind-tunnel models

A protective shell mechanism for wind tunnel models was developed and tested. The mechanism is passive in operation, reliable, and imposes no new structural design changes for wind tunnel models. Methods of predicting the release time and the measured loads associated with the release of the shell are given. The mechanism was tested in a series of wind tunnel tests to validate the removal process and measure the pressure loads on the model. The protective shell can be used for wind tunnel models that require a step input of heating and loading such as a thin skin heat transfer model. The mechanism may have other potential applications.

Puster, R. L.↗

NASA NTRS2001

Cryogenic Propellant Long-term Storage With Zero Boil-off

Significant boil-off losses of cryogenic propellant storage systems in long-duration space mission applications result in additional propellant and large tanks. The zero boil-off (ZBO) concept consists of an active cryo-cooling system integrated with traditional passive thermal insulation. The potential mass reductions with the ZBO concept are Substantial; therefore, further exploration through technology programs has been initiated within NASA. A large-scale demonstration of the ZBO concept has been devised utilizing the Marshall Space Flight Center (MSFC) Multipurpose Hydrogen Test Bed (MHTB) along with a cryo-cooler unit. The cryo-cooler with the MHTB and spraybar recirculation/mixer system in a manner that enables thermal energy removal at a rate that equals the total tank heat leak. The liquid hydrogen is withdrawn from the tank, passed through a heat exchanger, and then the chilled liquid is sprayed back into the tank through a spraybar. The test series will be performed over a 30-40 day period. Tests will be conducted at multiple fill levels and various mixer operational cycles to demonstrate concept viability and to provide benchmark data to be used in analytical model development. In this paper. analytical models for heat flows through the MHTB tank, cryo-cooler performance. and spraybar performance will be presented.

Hedayat, A.↗