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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 91 records · Page 5

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NASA NTRS1986

Design study of an entry probe spectro-reflectometer

A wind tunnel was built to simulate the rapid movement of an entry probe through the Jupiter atmosphere. Wind speeds range from 1 to 50 meters per second in a closed system. Wind velocity and temperature probes as well as a cryogenically cooled cold finger can be placed in the 6 inch diameter viewing section. The initial testing of the wind tunnel involved running sectional profiles through the observation port of air currents of 0.1 to 3.0 atmosphere. The velocity profile was very uniform throughout the cross section of the experimental port, with the exception of the wall effects. The deposition of cooled volatiles using the wind tunnel was not performed. However, measurements of the deposition of H2O ice on a cryogenically cooled thickness modulator were made under ambient conditions, namely room temperature and pressure. In the Frost Depositon Test Facility, ice deposition was measured at thicknesses of about a half millimeter and frost was produced whose thickness reflectivity could easily be measured by reflectance spectroscopy.

Sill, G. T.↗

NASA NTRS1996

Development of a Pressure Box to Evaluate Reusable-Launch-Vehicle Cryogenic-Tank Panels

A cryogenic pressure-box test machine has been designed and is being developed to test full-scale reusable launch vehicle cryogenic-tank panels. This machine is equipped with an internal pressurization system, a cryogenic cooling system, and a heating system to simulate the mechanical and thermal loading conditions that are representative of a reusable launch vehicle mission profile. The cryogenic cooling system uses liquid helium and liquid nitrogen to simulate liquid hydrogen and liquid oxygen tank internal temperatures. A quartz lamp heating system is used for heating the external surface of the test panels to simulate cryogenic-tank external surface temperatures during re-entry of the launch vehicle. The pressurization system uses gaseous helium and is designed to be controlled independently of the cooling system. The tensile loads in the axial direction of the test panel are simulated by means of hydraulic actuators and a load control system. The hoop loads in the test panel are reacted by load-calibrated turnbuckles attached to the skin and frame elements of the test panel. The load distribution in the skin and frames can be adjusted to correspond to the tank structure by using these turnbuckles. The seal between the test panel and the cryogenic pressure box is made from a reinforced Teflon material which can withstand pressures greater than 52 psig at cryogenic temperatures. Analytical results and tests on prototype test components indicate that most of the cryogenic-tank loading conditions that occur in flight can be simulated in the cryogenic pressure-box test machine.

Ambur, Damodar R.↗

NASA NTRS1996

Development of a Pressure Box to Evaluate Reusable-Launch-Vehicle Cryogenic-Tank Panels

A cryogenic pressure-box test machine has been designed and is being developed to test full-scale reusable-launch-vehicle cryogenic-tank panels. This machine is equipped with an internal pressurization system, a cryogenic cooling system, and a heating system to simulate the mechanical and thermal loading conditions that are representative of a reusable-launch-vehicle mission profile. The cryogenic cooling system uses liquid helium and liquid nitrogen to simulate liquid hydrogen and liquid oxygen tank internal temperatures. A quartz lamp heating system is used for heating the external surface of the test panels to simulate cryogenic-tank external surface temperatures during re-entry of the launch vehicle. The pressurization system uses gaseous helium and is designed to be controlled independently of the cooling system. The tensile loads in the axial direction of the test panel are simulated by means of hydraulic actuators and a load control system. The hoop loads in the test panel are reacted by load-calibrated turnbuckles attached to the skin and frame elements of the test panel. The load distribution in the skin and frames can be adjusted to correspond to the tank structure by using these turnbuckles. The seal between the test panel and the cryogenic pressure box is made from a reinforced Teflon material which can withstand pressures greater than 52 psig at cryogenic temperatures. Analytical results and tests on prototype test components indicate that most of the cryogenic-tank loading conditions that occur in flight can be simulated in the cryogenic pressure-box test machine.

Ambur, Damodar R.↗

NASA NTRS2004

Debonding Stress Concentrations in a Pressurized Lobed Sandwich-Walled Generic Cryogenic Tank

A finite-element stress analysis has been conducted on a lobed composite sandwich tank subjected to internal pressure and cryogenic cooling. The lobed geometry consists of two obtuse circular walls joined together with a common flat wall. Under internal pressure and cryogenic cooling, this type of lobed tank wall will experience open-mode (a process in which the honeycomb is stretched in the depth direction) and shear stress concentrations at the junctures where curved wall changes into flat wall (known as a curve-flat juncture). Open-mode and shear stress concentrations occur in the honeycomb core at the curve-flat junctures and could cause debonding failure. The levels of contributions from internal pressure and temperature loading to the open-mode and shear debonding failure are compared. The lobed fuel tank with honeycomb sandwich walls has been found to be a structurally unsound geometry because of very low debonding failure strengths. The debonding failure problem could be eliminated if the honeycomb core at the curve-flat juncture is replaced with a solid core.

Ko, William L.↗

NASA NTRS1980

Preliminary cryogenic performance of the Shuttle Infrared Telescope Facility

The Shuttle Infrared Telescope Facility (SIRTF) is a cryogenically cooled telescope in the one-meter aperture class designed for sensing in the infrared from 2-200 microns. This facility is designed to be flown many times on the Space Shuttle with varying instrument complements. All components of the SIRTF within the field of view of the optics are cryogenically cooled. The primary coolant is supercritical helium which is stored in an external tank and routed through the telescope - cooling the instruments first, then the optical components and finally the baffles. For detector cooling below 6K small reservoirs of superfluid helium (He II) are provided. The SIRTF cryogenic system is designed to automatically control the tank pressure and telescope flow rates during prelaunch operations and flight as well as meet the Space Shuttle environmental and safety requirements. Temperatures maintained in the telescope are a function of instrument operation, design, energy dissipation, and telescope pointing angle. By control of the cryogen flow rate any selected instrument temperature can be maintained within fixed limits, and the critical secondary mirror can be maintained below 10K throughout a 14-day mission. Instrument thermal design is a critical factor in the maintenance of proper temperature differences in the experiment package. Design of a cryogenic telescope for space use presents many problems which do not exist in earth based systems. The limited opportunity for servicing, the restricted coolant supply, and the remote instrumentation and control all provide new considerations for the instrument and system designers.

Gier, H. L.↗

NASA NTRSDate not supplied

Selecting an Encapsulant for an Aerospace Superconducting Machine

Achieving larger benefits from electrified propulsion in single aisle aircraft (the largest commercial aircraft market segment) necessitates that a significant fraction of their 20 MW or greater propulsion system be electrified. These aircraft would require up to 10-20 of today’s state-of-the art machines, which have been demonstrated up to 2.5 MW for aerospace use, and could benefit further from 5 MW+ designs. However, when conventionally cooled, high power density machines still produce a significant amount of waste heat, translating into heavy thermal management and detracting from system benefits. Highly efficient fully superconducting electric machines (or those with a cryogenically cooled, high purity copper or aluminum stator) are a possible solution but have multiple barriers to overcome. One such barrier is the durability of superconducting windings. Superconductors are typically brittle, and encapsulants used to hold windings in place are a significant source of stress due to mismatches in coefficient of thermally induced contraction between ambient and operational temperatures (20 to 77 K). Lack of compliance between the materials at operational temperatures also adds significant stress. These encapsulants also form a thermal barrier that can be detrimental to cooling the superconductors. This work describes an initial study of commercially available encapsulants as it relates to superconducting machine applications, along with initial modeling of thermal stress in superconducting windings for a superconducting or cryogenically cooled stator in a 5 MW electric machine.

encapsulant↗

NASA NTRSDate not supplied

Selecting an Encapsulant for an Aerospace Superconducting Machine

Achieving larger benefits from electrified propulsion in single aisle aircraft (the largest commercial aircraft market segment) necessitates that a significant fraction of their 20 MW or greater propulsion system be electrified. 5 to possibly 20 of the MW-scale electric machines investigated by NASA would be required to meet this need. Approximately 10-20 of NASA’s MW-scale electric machines would be required to reach the necessary power levels. Therefore, electric machines of 5 MW or greater are of interest. However, conventionally cooled high power density MW-scale electric machines still produce a significant amount of waste heat, which makes obtaining these power levels problematic. Highly efficient fully superconducting electric machines (or those with a cryogenically cooled, high purity copper or aluminum stator) are a possible solution but have multiple barriers to be overcome. One such barrier is the durability of superconducting windings. Superconductors are typically brittle, and encapsulants used to hold windings in place are a significant source of stress because of the mismatches in coefficient of thermal expansion at temperatures between room temperature and operational temperatures (20 to 77 K). These encapsulants also form a thermal barrier that can be detrimental to cooling the superconductors. This paper describes an initial study of commercially available encapsulants as it relates to superconducting machine applications along with initial modeling of thermal stress in superconducting windings for a superconducting or cryogenically cooled stator in a 5 MW electric machine.

encapsulant↗

NASA NTRS1973

Chemical reactivity of hydrogen, nitrogen, and oxygen atoms at temperatures below 100 k

The synthesis of unusual compounds by techniques employing cryogenic cooling to retard their very extreme reactivity was investigated. Examples of such species that were studied are diimide (N2H2), cyclobutadiene (C4H4), cyclopropanone (C3H4O), oxirene (C2H2O), and many others. Special purpose cryogenically cooled inlet arrangements were designed such that the analyses incurred no warm-up of the cold, and frequently explosively unstable, compounds. Controlled energy electron impact techniques were used to measure critical potentials and to develop the molecular energetics and thermodynamics of these molecules and to gain some insight into their kinetic characteristics as well. Three and four carbon strained ring molecules were studied. Several reactions of oxygen and hydrogen atoms with simple molecules of H, N, C, and O in hard quench configurations were studied. And the quench stabilization of BH3 was explored as a model system in cryochemistry.

Mcgee, H. A., Jr.↗

NASA NTRS1983

Thermal modeling of the Shuttle Infrared Telescope Facility

The Shuttle Infrared Telescope Facility (SIRTF) is a cryogenically cooled telescope in the one-meter aperture class designed for sensing in the infrared from 2-200 microns. This facility is currently planned for multiple missions onboard the Space Shuttle with varying instrument complements. All components of the SIRTF within the field of view of the optics are cryogenically cooled. The baseline primary coolant is supercritical helium which is stored in an external tank and routed through the telescope-cooling the instruments, the optical components and the baffles. For detector cooling below 6 K, small reservoirs of superfluid helium (HeII) are provided. The SIRTF was thermally modeled on the SINDA computer program both for steady state and transient solutions. The analysis shows that the baseline configuration has a large capacity for growth in cryogen requirements. A proportional controller model was developed for transient operations. The control system maintained the optics within all prescribed temperature limits except for certain combinations of transients involving a large step change in the power dissipation in the secondary mirror assembly and/or when the primary mirror was assumed to be constructed of quartz. The baseline SIRTF will perform the mission for which it was designed.

Gier, H. L.↗

NASA NTRS1992

A comparison of superconductor and manganin technology for electronic links used in space mission applications

The electronic link connecting cryogenically cooled radiation detectors to data acquisition and signal processing electronics at higher temperatures contributes significantly to the total heat load on spacecraft cooling systems that use combined mechanical and cryogenic liquid cooling. Using high transition temperature superconductors for this link has been proposed to increase the lifetime of space missions. Herein, several YBCO (YBa2Cu3O7) superconductor-substrate combinations were examined and total heat loads were compared to manganin wire technology in current use. Using numerical solutions to the heat-flow equations, it is shown that replacing manganin technology with YBCO thick film technology can extend a 7-year mission by up to 1 year.

Caton, R.↗

NASA NTRS1987

Dynamic analysis and design of the SIRTF primary mirror mount

The criteria and considerations for the design of the support system for the Space Infrared Telescope Facility (SIRTF) primary mirror are presented. A flexural-gimbal-baseplate design for the 0.5 m primary mirror was developed. Preliminary studies have indicated that this design may be further improved by replacing the flexures by a post-gimbal system wherein the gimbal design accomodates both the cryogenic cool down effects, the dynamic launch loads, and manufacturing tolerance effects. Additionally, a prestressed baseplate concept had evolved and was presented for the full scale 1.0 m mirror. However, preliminary design studies indicate that this concept will not be required, and the post-gimbal-baseplate design similar to the 0.5 m alternate support system will meet the cryogenic cool down, dynamic launch load criteria, and manufacturing tolerance effects.

Richard, Ralph M.↗

NASA NTRS1998

Design and Testing of a Cryogenic Capillary Pumped Loop Flight Experiment

This paper details the flight configuration and pre-flight performance test results of the fifth generation cryogenic capillary pumped loop (CCPL-5). This device will fly on STS-95 in October 1998 as part of the CRYOTSU Flight Experiment. This flight represents the first in-space demonstration of a CCPL, a miniaturized two-phase fluid circulator for thermally linking cryogenic cooling sources to remote cryogenic components. CCPL-5 utilizes N2 as the working fluid and has a practical operating range of 75-110 K. Test results indicate that CCPL-5, which weighs about 200 grams, can transport over 10 W of cooling a distance of 0.25 m (or more) with less than a 5 K temperature drop.

Bugby, David C.↗

NASA NTRS1965

Insulation accelerates rate of cooling with cryogenic fluid

Thermal insulating material increases the rate of heat transfer from the interior of a chamber to a liquid nitrogen-filled metal jacket. A thin film of the material is bonded to the surface of the metal wall facing the liquid nitrogen.

Allen, L. D.↗

NASA NTRS1975

Cryogenic Quartz Crystal Microbalance

A radiatively cooled Cryogenic Quartz Crystal Microbalance designed to monitor highly volatile contaminants on the shuttle is described. Measurements are made with two 15-MHz microbalances having removable, optically polished sensors mounted in a radiant cooler. One sensor operates below the freezing point of water and monitors contamination including that of water vapor. The second sensor is heated and monitors the contamination background. It provides a reference from which the density of the water vapor cloud enveloping the shuttle is determined. The design incorporates a low-power dissipation oscillator, heaters for ice removal, and a method for attaching second-surface mirrors to the radiator employing an indium type solder instead of a room temperature vulcanizer.

D Mckeown↗

NASA NTRSDate not supplied

Current Status and Future Plans for Electric Motors and Drives at NASA

Current Status and Future Plans for Electric Motors and Drives at NASA: Our work advances propulsion for aircraft while reducing energy consumption, noise, emissions and the cost of air travel. We are committed to investigating the use of alternative energy sources and improving the safety and expediency of flight. Electrified Aircraft Propulsion (EAP) is the use of propulsors (propellers or fans) driven by electric motors to propel aircraft ranging from air taxis to subsonic transports. NASA is developing technology, aircraft concepts, test aircraft, and ground test facilities to turn this idea from science fiction to reality. Specifically, motors and/or generators (Electric machines) are needed on all electrified aircraft. And NASA is sponsoring or performing work to achieve power densities 2-3 times the state of the art for machines in the MW or larger class. Three major machine types are being developed: permanent magnet, induction, and wound field. Power converters are also an essential component in most EAP aircraft concepts, as they are used to convert from ac to dc power, or vice versa. Silicon carbide and gallium nitride convertors are being developed with conventional cooling as well as a cryogenically cooled converter. Future plans include demonstrating integrated flight-ready systems in both ground and flight tests; collaborating with and leveraging ARPA-E EAP programs; and supporting FAA standards development for market acceptance and safety.

Powertrain↗

NASA NTRSDate not supplied

Current Status and Future Plans for Electric Motors and Drives at NASA

Our work advances propulsion for aircraft while reducing energy consumption, noise, emissions and the cost of air travel. We are committed to investigating the use of alternative energy sources and improving the safety and expediency of flight. Electrified Aircraft Propulsion (EAP) is the use of propulsors (propellers or fans) driven by electric motors to propel aircraft ranging from air taxis to subsonic transports. NASA is developing technology, aircraft concepts, test aircraft, and ground test facilities to turn this idea from science fiction to- reality. Specifically, motors and/or generators (Electric machines) are needed on all electrified aircraft. And NASA is sponsoring or performing work to achieve power densities 2-3 times the state of the art for machines in the MW or larger class. Three major machine types are being developed: permanent magnet, induction, and wound field. Power converters are also an essential component in most EAP aircraft concepts, as they are used to convert from ac to dc power, or vice versa. Silicon carbide and gallium nitride convertors are being developed with conventional cooling as well as a cryogenically cooled converter. Future plans include demonstrating integrated flight-ready systems in both ground and flight tests; collaborating with and leveraging ARPA-E EAP programs; and supporting FAA standards development for market acceptance and safety.

Aircraft↗

NASA NTRS1990

Thermal performance of a five year lifetime superfluid helium dewar for SIRTF

The Space Infrared Telescope Facility (SIRTF) is a 1 m class cryogenically cooled observatory for infrared astronomy. The SIRTF cryogenic system has to satisfy the five year mission lifetime requirement as well as to provide sufficient cooling for the science instruments and optical system. A 4000 cu dm superfluid helium dewar has been selected for the current baseline cryogenic system which represents the largest superfluid helium dewar proposed to date for a long lifetime space-borne application. This paper discusses the design and predicted performance of the current cryogenic system, as well as its comparison with IRAS and other space-borne superfluid helium dewars currently under development.

Lee, J. H.↗

NASA NTRS2011

Overview of the James Webb Space Telescope Observatory

The James Webb Space Telescope (JWST) is a cryogenic, 6.5 meter diameter space telescope. JWST has a unique architecture, compared to previous space telescopes, that is driven by its science requirements, ia passively cooled cryogenic design, and the need to stow the observatory for launch. JWST's large, segmented mirror meets the requirement for high angular resolution in the infrared coupled with a significant increase in collecting area compared to the Spitzer and Hubble Space telescopes in order to detect the first galaxies. JWST's unique five-layer sunshield allows the telescope and instrument module to passively cool to cryogenic temperatures. JWST will be launched on an Ariane 5, and so both its telescope optics, and the sunshield have to be stowed in order to fit the Ariane 5 fairing. Following launch the sunshield and telescope optics must be deployed, and the primary mirror phased for science operations. In this presentation we will review the design of the observatory and highlight recent progress in the construction of the JWST observatory. In particular, we address recent progress with the telescope optics, sunshield and spacecraft. We will discuss predicted observatory performance in terms of the scientific goals of JWST and address key operational considerations that might bear upon frontier science observations.

Clampin, Mark↗