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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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A discussion of the power requirements for the Mars Pathfinder Mission is given. Topics include: battery requirements; cell design; battery design; test descriptions and results. A summary of the results is also included.
Most cells survived the 3 amp (A) over-discharge at room temperature for 2 hours. The cell that failed was the LTC-114 after high rate discharge of 500 mA similar to the results of the 1 A over-discharge test. Most cells opened during 0.05 Ohm short circuit test without incident but three LTC-111 cells exploded apparently due to a lack of a thermal cutoff switch. The LTC-114 cells exposed to a hard short of 0.05 Ohms recovered but the LTC-114 cells exposed to a soft short of 1 Ohm did not. This is probably due to the activation of a resetable fuse during a hard short. Fresh cells tend to survive exposure to higher temperatures than cells previously discharged at high rate (1 Amp). LTC-111 cells tend to vent at lower temperatures than the all LTC-114 cells and the LTC-115 cells that were previously discharged at rates exceeding 1 Amp.
Long life thermal cell using mixture of lithium chloride and potassium chloride as electrolyte
A 1-D mathematical model for the lithium/thionyl chloride primary cell was developed to investigate methods of improving its performance and safety. The model includes many of the components of a typical lithium/thionyl chloride cell such as the porous lithium chloride film which forms on the lithium anode surface. The governing equations are formulated from fundamental conservation laws using porous electrode theory and concentrated solution theory. The model is used to predict 1-D, time dependent profiles of concentration, porosity, current, and potential as well as cell temperature and voltage. When a certain discharge rate is required, the model can be used to determine the design criteria and operating variables which yield high cell capacities. Model predictions can be used to establish operational and design limits within which the thermal runaway problem, inherent in these cells, can be avoided.
Lithium chloride power plant theory and technology, noting application to critical weapons systems
Sodium fluoride (NaF) has been found to be an activation agent in exfoliating a hexagonal boron nitride (hBN) platelet, using solvent free method. The procedure was carried out by enhancing the intercalation of ferric chloride (FeCl3) in an intermediate step, up to 330 °C, followed by removal of the by-product at room temperature. In this research, five additional common salts including lithium fluoride, potassium fluoride, lithium chloride, sodium chloride, and potassium chloride, were examined and compared to NaF for their effectiveness in producing the most exfoliation of a commercially available sub-micron-size hBN. It was found that, all fluoride and chloride salts significantly activated the intercalation of FeCl3 into this hBN. Analyses and characterization from X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and Raman spectroscoy revealed NaCl to be one of most effective agents without further heat treatment and the least expensive salt in the intercalating reaction and exfoliation process. The synthetic route of this solvent free method is straightforward with 89% yield and above which can be produced on a large scale.
Electrolyte increases life on oxygen sensors in a polarograph used for measuring the partial pressure of oxygen in a gas mixture. It consists of a solution of lithium chloride, dimethyl acetamide and water.
Two principle areas studied were stress corrosion crack growth rates of a titanium alloy in liquid environments containing halide ions and pitting corrosion of titanium in bromide solutions. Two initial assumptions were made, that the rate of propagation was controlled by a macroscopic solution parameter and that this parameter was viscosity. A series of solutions were prepared using lithium chloride as the solute and water, methanol, glycerin, formic acid, acetone, dimethyl sulphoxide, etc. As solvents, these solutions were prepared with a 5:1 solvent-solute ratio. Viscosity was varied by changing the temperature and it was found: (1) In all solvents the velocity of cracking was proportional to the reciprocal of the viscosity. (2) Each solvent gave a separate relationship, (3) The temperature dependence and numerical values for the apparent activation energy of cracking and viscosity were the same.
Chemical method of measuring volume of urine samples using lithium chloride dilution technique, does not interfere with analysis, is faster, and more accurate than standard volumetric of specific gravity/weight techniques. Adaptation of procedure to urinalysis could prove generally practical for hospital mineral balance and catechoamine determinations.
After thermal cauterization of the area postrema in rats, the absence of conditioned taste aversion of sucrose paired with lithium chloride (0.15M, 3.3 ml/kg) was used as a pharmacologic/behavioral index of area postrema damage. In a subsequent experiment the effects of area postrema lesions on three measures proposed as species-relevant measures of motion sickness were studied, using off-vertical rotation at 150 deg/s for either 30 or 90 min. Lesions of area postrema did not alter postrotational suppression of drinking or amount of defecation during motion. The initial acquisition of conditioned taste aversion to a novel cider vinegar solution paired with motion was not affected by lesioning of the area postrema, but these taste aversions extinguished more slowly in lesioned rats than in sham-operates or intact controls. Results are discussed in terms of proposed humoral factors which may induce motion sickness and in light of recent data on the role of the area postrema in similar measures in species possessing the complete emetic reflex.
A conversion coating solution and process forms a stable and corrosion-resistant layer on metal substrates or layers or, more preferably, on a boehmite layer or other base conversion coating. The conversion coating process involves contacting the substrate, layer or coating with an aqueous alkali metal isomolybdate solution in order to convert the surface of the substrate, layer or coating to a stable conversion coating. The aqueous alkali metal molybdates are selected from sodium molybdate (Na.sub.2 MoO.sub.4), lithium molybdate (Li.sub.2 MoO.sub.4), potassium molybdate (K.sub.2 MoO.sub.4), or combinations thereof, with the most preferred alkali metal molybdate being sodium molybdate. The concentration of alkali metal molybdates in the solution is preferably less than 5% by weight. In addition to the alkali metal molybdates, the conversion coating solution may include alkaline metal passivators selected from lithium nitrate (LiNO.sub.3), sodium nitrate (NaNO.sub.3), ammonia nitrate (NH.sub.4 NO.sub.3), and combinations thereof; lithium chloride, potassium hexafluorozirconate (K.sub.2 ZrF.sub.6) or potassium hexafluorotitanate (K.sub.2 TiF.sub.6).
For decades advanced spacesuit developers have pursued a regenerable, robust non-venting system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's lithium chloride Heat Pump Radiator (HPR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. The SEAR is evacuated at the onset of operations and thereafter, the water vapor absorption rate of the HPR maintains a low pressure environment for the SWME to evaporate effectively. This water vapor captured by solid LiCl in the HPR with a high enthalpy of absorption, results in sufficient temperature lift to reject most of the heat to space by radiation. After the sortie, the HPR would be heated up in a regenerator to drive off and recover the absorbed evaporant. A one-fourth scale prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The HPR was able to stably reject 60 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.
For decades advanced spacesuit developers have pursued a regenerable, robust nonventing system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s Lithium Chloride Absorber Radiator (LCAR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. This water vapor is then captured by solid LiCl in the LCAR with a high enthalpy of absorption, resulting in sufficient temperature lift to reject heat to space by radiation. After the sortie, the LCAR would be heated up and dried in a regenerator to drive off and recover the absorbed evaporant. A engineering development prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The LCAR was able to stably reject 75 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.
A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 m2 radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduces the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.
This paper describes the design and development of an innovative thermal and humidity control system for future space suits. The system comprises an evaporation cooling and dehumidification garment (ECDG) and a lithium chloride absorber radiator (LCAR). The ECDG absorbs heat and water vapor from inside the suit pressure garment, while the LCAR rejects heat to space without venting water vapor. The ECDG is built from thin, flexible patches with coversheets made of non-porous, water-permeable membranes that -enclose arrays of vapor flow passages. Water vapor from inside the spacesuit diffuses across the water permeable membranes, enters the vapor flow channels, and then flows to the LCAR, thus dehumidifying the internal volume of the space suit pressure garment. Additional water evaporation inside the ECDG provides cooling for sensible heat loads. -The heat released from condensation and absorption in the LCAR is rejected to the environment by thermal radiation. We have assembled lightweight and flexible ECDG pouches from prototypical materials and measured their performance in a series of separate effects tests under well-controlled, prototypical conditions. Sweating hot plate tests at typical space suit pressures show that ECDG pouches can absorb over 60 W/ft of latent heat and 20 W/ft of sensible heat from the pressure garment environment. These results are in good agreement with the predictions of our analysis models.
A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 sq m radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduce the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.
Spacesuit Water Membrane Evaporator - Baseline heat rejection technology for the Portable Life Support System of the Advanced EMU center dot Replaces sublimator in the current EMU center dot Contamination insensitive center dot Can work with Lithium Chloride Absorber Radiator in Spacesuit Evaporator Absorber Radiator (SEAR) to reject heat and reuse evaporated water The Spacesuit Water Membrane Evaporator (SWME) is being developed to replace the sublimator for future generation spacesuits. Water in LCVG absorbs body heat while circulating center dot Warm water pumped through SWME center dot SWME evaporates water vapor, while maintaining liquid water - Cools water center dot Cooled water is then recirculated through LCVG. center dot LCVG water lost due to evaporation (cooling) is replaced from feedwater The Independent TCV Manifold reduces design complexity and manufacturing difficulty of the SWME End Cap. center dot The offset motor for the new BPV reduces the volume profile of the SWME by laying the motor flat on the End Cap alongside the TCV.
Future manned space exploration missions will require space suits with capabilities beyond the current state of the art. Portable Life Support Systems for these future space suits face daunting challenges, since they must maintain healthy and comfortable conditions inside the suit for longduration missions while minimizing weight and water venting. We have demonstrated the feasibility of an innovative, multipurpose garment for thermal and humidity control inside a space suit pressure garment that is simple, rugged, compact, and lightweight. The garment is a based on a conventional liquid cooling and ventilation garment (LCVG) that has been modified to directly absorb latent heat as well as sensible heat. This hybrid garment will prevent buildup of condensation inside the pressure garment, prevent loss of water by absorption in regenerable CO2 removal beds, and conserve water through use of advanced lithium chloride absorber/radiator (LCAR) technology for nonventing heat rejection. We have shown the feasibility of this approach by sizing the critical components for the hybrid garment, developing fabrication methods, building and testing a proof-of-concept system, and demonstrating by test that its performance is suitable for use in space suit life support systems.