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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

Using Mylar-Insulated Cryopumping Panels to Improve Vacuum Level During Warm Temperature Testing at JSC's Large Thermal Vacuum Facilities

Johnson Space Center’s Space Environment Simulation Lab (SESL) has both Chamber A, the world’s largest purpose-built thermal vacuum chamber capable of creating deep space conditions, and Chamber B, the largest human rated thermal vacuum chamber. A unique design feature of these chambers is the gaseous helium cryopumping panels within the liquid nitrogen shroud. This shroud is used to bring the chamber to cryogenic temperatures while the cryopumping panels trap gasses on its surface area to create a high vacuum environment of 5*10-6 Torr. In preparation for the James Webb Space Telescope (JWST) flight test, a series of functionals required the chamber to run at higher temperatures, and therefore did not need active cooling from the liquid nitrogen shroud. During testing, cryopumping panels were used to mitigate contamination during this main shroud warm-up. One of the cryopumping panels in Chamber A was covered with several layers of aluminized mylar to thermally protect the zone from the warmed shroud. This strategy was effective and became part of operations during JWST testing. Currently, Chamber B has requests for both commercial and NASA space suit tests at both high and low temperatures to validate thermal models. High temperature tests could benefit from reduced heater demand with an insulated shroud while still sustaining the high vacuum environment provided by the cryopumping panels. This paper will quantitatively define the thermal loads on the panels used in previous Chamber A warm up sequences. Additionally, this report will perform thermal analyses to assess the feasibility of adding layers of aluminized mylar to the cryopumping panels of Chamber B.

Cryogenics↗
NASA NTRS1984

Simultaneous thermal vacuum testing of GPS drives for NavStar

The solar array drive assemblies for the global positioning satellite (GPS) were built and the need to perform thermal vacuum acceptance testing on at least two complete units simultaneously is emphasized. The safety of the flight hardware is of primary importance. It is found that simultaneous space simulation testing of two complete drive packages requires only minor modification to the high vacuum pump stack. Attention is given to upgrading system safeties for high vacuum operation. Major modifications are designed and implemented for the thermal control system and supporting subsystems. The automated thermal control system and test bed hardware are of primary interest.

Brown, T. G.↗
NASA NTRS2016

Silicon-Carbide Power MOSFET Performance in High Efficiency Boost Power Processing Unit for Extreme Environments

Silicon-Carbide device technology has generated much interest in recent years. With superior thermal performance, power ratings and potential switching frequencies over its Silicon counterpart, Silicon-Carbide offers a greater possibility for high powered switching applications in extreme environment. In particular, Silicon-Carbide Metal-Oxide- Semiconductor Field-Effect Transistors' (MOSFETs) maturing process technology has produced a plethora of commercially available power dense, low on-state resistance devices capable of switching at high frequencies. A novel hard-switched power processing unit (PPU) is implemented utilizing Silicon-Carbide power devices. Accelerated life data is captured and assessed in conjunction with a damage accumulation model of gate oxide and drain-source junction lifetime to evaluate potential system performance at high temperature environments.

Ikpe, Stanley A.↗
NASA NTRS2010

Hypervelocity Impact Performance of Open Cell Foam Core Sandwich Panel Structures

Open cell metallic foam core sandwich panel structures are of interest for application in spacecraft micrometeoroid and orbital debris shields due to their novel form and advantageous structural and thermal performance. Repeated shocking as a result of secondary impacts upon individual foam ligaments during the penetration process acts to raise the thermal state of impacting projectiles ; resulting in fragmentation, melting, and vaporization at lower velocities than with traditional shielding configurations (e.g. Whipple shield). In order to characterize the protective capability of these structures, an extensive experimental campaign was performed by the Johnson Space Center Hypervelocity Impact Technology Facility, the results of which are reported in this paper. Although not capable of competing against the protection levels achievable with leading heavy shields in use on modern high-risk vehicles (i.e. International Space Station modules), metallic foam core sandwich panels are shown to provide a substantial improvement over comparable structural panels and traditional low weight shielding alternatives such as honeycomb sandwich panels and metallic Whipple shields. A ballistic limit equation, generalized in terms of panel geometry, is derived and presented in a form suitable for application in risk assessment codes.

Ryan, S.↗
NASA NTRS1979

Evaluation of an air solar collector

Performance verification under simulated conditions tested by using Marshall Space Flight Center solar simulator is presented. Evaluation included thermal performance tests, time constant tests, and incident angle modifier tests.

Source record↗
NASA NTRSDate not supplied

Multiscale and Multifidelity Modeling of a 3D Woven Composite Thermal Protection System

Complex three-dimensional (3D) woven composites have been considered by multiple NASA projects in recent years as a means of offering improved mechanical and thermal performance over traditional laminated composite systems. Parallel efforts have focused on developing simulation capabilities for these systems, which have traditionally and heavily relied on experimental testing to evaluate composite performance. One system is the Heatshield for Extreme Entry Environment Technology (HEEET), which is being considered for the thermal protection system on reentry spacecraft. Optical microscopy was used to characterize the blended carbon and phenolic fiber tows. A section of HEEET insulation layer was imaged with high-resolution micro-computed tomography (microCT) and segmented to separate individual tows, porous matrix, and voids. These data were used to develop multiscale thermomechanical computational models within the NASA Multiscale Analysis Tool (NASMAT). Two NASMAT modeling approaches were considered to capture the details of the 3D woven architecture: a coarse model appropriate for inclusion in multiscale structural analyses and a high-fidelity model created by downsampling the microCT data. Both elastic and thermal properties were computed and compared. The feasibility and challenges associated with modeling complex, hybrid 3D woven composites were also addressed.

NASMAT↗
NASA NTRS1972

Cryogenic insulation development

Multilayer insulations for long term cryogenic storage are described. The development effort resulted in an insulation concept using lightweight radiation shields, separated by low conductive Dacron fiber tufts. The insulation is usually referred to as Superfloc. The fiber tufts are arranged in a triangular pattern and stand about .040 in. above the radiation shield base. Thermal and structural evaluation of Superfloc indicated that this material is a strong candidate for the development of high performance thermal protection systems because of its high strength, purge gas evacuation capability during boost, its density control and easy application to a tank.

Leonhard, K. E.↗
NASA NTRS2021

Designing a Decontamination Solution for the Low-Earth-Orbit, Cryogenic SPHEREx Mission

To address the scientific goals of NASA’s astrophysics division, the JPL and Caltech’s SPHEREx mission conducts the first near-infrared all-sky spectral survey in low-earth-orbit using a passively-cooled, cryogenic telescope. Several unique water contamination issues arise due to the combination of cryogenic operation temperatures and the limited temperature control authority of passive cooling. Because water molecules have adsorption bands within the wavelengths of interest for SPHEREx’s survey, it is imperative that water contamination be controlled and minimized. In this work, a model is developed for the SPHEREx mission to predict the transport and accumulation of outgassed water onto sensitive payload components. The model utilizes the time dependent thermal profiles of the individual payload components, initial water content, and spacecraft geometry to calculate the time dependent water diffusion, transport, and adsorption. This model is subsequently used to predict water contamination risks and design decontamination solutions for each risk. Two major water contamination risks were predicted, water accumulation during cooldown and on cryogenic surfaces during the mission. The first risk occurs during the cooldown of the payload to cryogenic temperatures, predicting water accumulation on optical surfaces in excess of the allowable levels. To mitigate this accumulation, the temperature of the optical surfaces is controlled during cooldown through a combination of heaters and spacecraft pointing. The second risk is that over the course of the mission, is unavoidable water accumulation onto the payload thermal system’s cryogenic surfaces, possibly jeopardizing thermal performance and temperature stability, both of which are required for science success. To decontaminate any water that had collected onto cryogenic thermal system surfaces, a decontamination maneuver was designed. In this decontamination maneuver, cryogenic surfaces of the thermal system are warmed to a temperature where water will desorb by spacecraft pointing while still meeting all avoidance constraints, and thereby avoiding undue risk to the observatory hardware. Through application of the developed analytical model and inclusion of the decontamination maneuver in the mission design, SPHEREx can confidently demonstrate that it is able to decontaminate, at the start of and during the mission as needed to meet its end of life science performance requirements.

Soares, Carolos E.↗
NASA NTRS1974

Thermal design and performance of the Viking balloon-launched decelerator test vehicles

The thermal design and performance of the test vehicles used for the flight-qualification of the Viking parachute system are described. The desired range of test conditions was provided by a subsonic drop from a balloon altitude of 90,000 feet, and rocket-powered transonic and supersonic flights initiated at balloon altitudes of 120,000 feet. Unusual aspects of the thermal design approach included the application of techniques developed in support of planetary programs to the thermal analysis of balloon payloads and the use of ground firing data to establish realistic upper bounds for radiant plume heating during flight. The adequacy of thermal design is verified by flight data.

Buna, T.↗
NASA NTRS1979

Hot-air flat-plate solar collector-design package

Report contains design data, performance specifications, and drawings for hot-air flat-plate solar-energy collector. Evaluation consists of tests on thermal performance time constance, and incidence angle modifier test. Results are presented in table and graph form and are analyzed in detail.

Source record↗
NASA NTRS1978

Applications of thermal energy storage in the cement industry

In the manufacture of cement, literally trillions of Btu's are rejected to the environment each year. The purpose of this feasibility study program was to determine whether thermal energy storage could be used to conserve or allow alternative uses of this rejected energy. This study identifies and quantifies the sources of rejected energy in the cement manufacturing process, established use of this energy, investigates various storage system concepts, and selects energy conservation systems for further study. Thermal performance and economic analyses are performed on candidate storage systems for four typical cement plants representing various methods of manufacturing cement. Through the use of thermal energy storage in conjunction with waste heat electric power generation units, an estimated 2.4 x 10 to the 13th power Btu/year, or an equivalent on investment of the proposed systems are an incentive for further development.

Jaeger, F. A.↗
NASA NTRS1981

NASA and Deere to study effects of low-g on iron processing

A technical exchange agreement to study the effects of processing iron alloys in microgravity is described. Alloy solidification experiments are to be performed in the low-g facilities at Marshall Space Center. Deere is to prepare and evaluate the samples, and perform thermal characterization studies of the furnace used for melting and solidifying the samples. Experiment planning and analysis are to be performed jointly and data shared between the two parties. The technical exchange concept, developed by NASA to involve the private sector in low gravity research programs, is described. Other low gravity processing fields in which industry is invited to participate are listed.

Source record↗
NASA NTRS1991

Higher-Performance Ambient-Temperature Heat Pipe

Improved version of heat pipe described in "High-Performance Ambient-Temperature Heat Pipe" (MFS-26062). Lining of sintered aluminum powder added to liquid channel. Results in improved thermal performance.

Ernst, Donald M.↗
NASA NTRS2011

Evaluation of Surface Modification as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

Three surface treatments were evaluated for their ability to lower the adhesion between lunar simulant dust and AZ93, AlFEP, and AgFEP thermal control surfaces under simulated lunar conditions. Samples were dusted in situ and exposed to a standardized puff of nitrogen gas. Thermal performance before dusting, after dusting, and after part of the dust was removed by the puff of gas, were compared to perform the assessment. None of the surface treatments was found to significantly affect the adhesion of lunar simulants to AZ93 thermal control paint. Oxygen ion beam texturing also did not lower the adhesion of lunar simulant dust to AlFEP or AgFEP. But a workfunction matching coating and a proprietary Ball Aerospace surface treatment were both found to significantly lower the adhesion of lunar simulants to AlFEP and AgFEP. Based on these results, it is recommended that all these two techniques be further explored as dust mitigation coatings for AlFEP and AgFEP thermal control surfaces.

Gaier, James R.↗
NASA NTRS2011

Evaluation of Surface Modification as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

Three surface treatments were evaluated for their ability to lower the adhesion between lunar simulant dust and AZ93, AlFEP, and AgFEP thermal control surfaces under simulated lunar conditions. Samples were dusted in situ and exposed to a standardized puff of nitrogen gas. Thermal performance before dusting, after dusting, and after part of the dust was removed by the puff of gas, were compared to perform the assessment. None of the surface treatments was found to significantly affect the adhesion of lunar simulants to AZ93 thermal control paint. Oxygen ion beam texturing also did not lower the adhesion of lunar simulant dust to AlFEP or AgFEP. But a workfunction matching coating and a proprietary Ball Aerospace surface treatment were both found to significantly lower the adhesion of lunar simulants to AlFEP and AgFEP. Based on these results, it is recommended that all these two techniques be further explored as dust mitigation coatings for AlFEP and AgFEP thermal control surfaces.

Gaier, James R.↗
NASA NTRS2017

Structural Heat Intercept, Insulation, and Vibration Evaluation Rig (SHIIVER)

Abstract: NASA is currently investigating methods to reduce the boil-off rate on large cryogenic upper stages. Two such methods to reduce the total heat load on existing upper stages are vapor cooling of the cryogenic tank support structure and integration of thick multilayer insulation systems to the upper stage of a launch vehicle. Previous efforts have flown a 2-layer MLI blanket and shown an improved thermal performance, and other efforts have ground-tested blankets up to 70 layers thick on tanks with diameters between 2 3 meters. However, thick multilayer insulation installation and testing in both thermal and structural modes has not been completed on a large scale tank. Similarly, multiple vapor cooled shields are common place on science payload helium dewars; however, minimal effort has gone into using boil-off to intercept heat on large structural surfaces associated with rocket stages. A majority of the vapor cooling effort focuses on metallic cylinders called skirts, which are the most common structural components for launch vehicles. In order to provide test data for comparison with analytical models, a 4 meter diameter test tank and assembly is currently being designed to include skirt structural systems with integral vapor cooling. In order to give a more representative result for actual applications, the technologies will be designed for an 8.4 m and scaled down to a 4 meter tank. In order to prove that the insulation system and vapor cooling attachment methods are structurally sound, acoustic testing will also be performed on the system. The test tank with insulation and vapor cooled shield installed will be tested thermally in the B2 test facility at NASAs Plum Brook Station both before and after being vibration tested at Plum Brooks Space Power Facility.

Johnson, Wesley↗
NASA NTRS2015

The Structural Heat Intercept-Insulation-Vibration Evaluation Rig (SHIVER)

NASA is currently investigating methods to reduce the boil-off rate on large cryogenic upper stages. Two such methods to reduce the total heat load on existing upper stages are vapor cooling of the cryogenic tank support structure and integration of thick multilayer insulation systems to the upper stage of a launch vehicle. Previous efforts have flown a 2-layer MLI blanket and shown an improved thermal performance, and other efforts have ground-tested blankets up to 70 layers thick on tanks with diameters between 2 3 meters. However, thick multilayer insulation installation and testing in both thermal and structural modes has not been completed on a large scale tank. Similarly, multiple vapor cooled shields are common place on science payload helium dewars; however, minimal effort has gone into intercepting heat on large structural surfaces associated with rocket stages. A majority of the vapor cooling effort focuses on metallic cylinders called skirts, which are the most common structural components for launch vehicles. In order to provide test data for comparison with analytical models, a representative test tank is currently being designed to include skirt structural systems with integral vapor cooling. The tank is 4 m in diameter and 6.8 m tall to contain 5000 kg of liquid hydrogen. A multilayer insulation system will be designed to insulate the tank and structure while being installed in a representative manner that can be extended to tanks up to 10 meters in diameter. In order to prove that the insulation system and vapor cooling attachment methods are structurally sound, acoustic testing will also be performed on the system. The test tank with insulation and vapor cooled shield installed will be tested thermally in the B2 test facility at NASAs Plumbrook Station both before and after being vibration tested at Plumbrooks Space Power Facility.

Cryogenic Fluid Management↗