Browse Topic: Superconductors

Items (48)

Supercool Mini-Thermometer

TBMG-3833501/01/2021

Researchers have developed a miniature superconducting thermometer that measures temperatures below 1 kelvin (-272.15 °C or -457.87 °F), down to 50 millikelvin (mK) and potentially 5 mK. It is smaller, faster, and more convenient than conventional cryogenic thermometers for chip-scale devices and could be mass-produced.

Magnetic Shield Using Proximity Coupled, Spatially Varying Superconducting Order Parameters

TBMG-3616503/01/2020

NASA Goddard Space Flight Center has developed a magnetic shielding design that features simplicity, ease of use, reproducibility, longevity, and scalability. It does not require activation, monitoring, or wiring. The invention uses the superconducting “proximity effect” and/or the “inverse proximity effect” to form a spatially varying order parameter. When designed to expel magnetic flux from a region of space, the proximity effect(s) are used in concert to make the superconducting order parameter strongly superconducting in the center and more weakly superconducting toward the perimeter. The shield is then passively cooled through the superconducting transition temperature.

Superconductivity in a Nickel Oxide Material

TBMG-3568912/01/2019

Scientists have made the first nickel oxide material that shows clear signs of superconductivity — the ability to transmit electrical current with no loss. Also known as a nickelate, it's the first unconventional superconductor that is very similar to copper oxides, or cuprates, which indicated that superconductors could someday operate at near-room-temperature and revolutionize electronic devices, power transmission, and other technologies. Those similarities may show that nickelates could also superconduct at relatively high temperatures.

New Class of Two-Dimensional Materials

TBMG-3542811/01/2019

A process was developed for producing oxide perovskite crystals in flexible, free-standing layers. A two-dimensional rendition of this substance is intriguing because 2D materials have been shown to possess remarkable electronic properties, including high-temperature superconductivity. Such compounds are prized as potential building blocks in multifunctional high-tech devices for energy and quantum computing, among other applications.

Singlet-Based Magnet for Enhanced Data Storage

TBMG-3440405/01/2019

Anew type of magnet — called a singlet-based magnet — was discovered that differs from conventional magnets in which small magnetic constituents align with one another to create a strong magnetic field. By contrast, the singlet-based magnet has fields that pop in and out of existence, resulting in an unstable force, but one that potentially has more flexibility than conventional counterparts.

Nickel Oxide Compound for High-Temperature Superconductors

TBMG-2817701/01/2018

Superconducting materials are technologically important because electricity flows through them without resistance. Only low-temperature superconductivity seemed possible before 1986, but materials that superconduct at low temperatures are impractical because they must first be cooled to hundreds of degrees below zero. In 1986, discovery of high-temperature superconductivity in copper oxide compounds, called cuprates, engendered new technological potential for the phenomenon.

Portable Superconductivity Systems for Small Motors

TBMG-2669004/01/2017

Superconductivity, where electrical currents travel unhindered through a material, has many practical uses. It is used in applications extending from MRIs in hospitals to the cavities of particle accelerators. However, practical exploitation of superconductivity also presents many challenges.

Epitaxial Growth of Rhenium with Sputtering

TBMG-2609512/01/2016

Epitaxial superconducting films of refractory metals are a promising new template for single crystal tunnel barriers in Josephson junction quantum bit (qubit) devices. In existing Josephson junction qubits, it is believed that the widely-used amorphous AlOx tunnel barriers have undesirable two-state fluctuators. It is speculated that single-crystal tunnel barriers such as sapphire (α-Al2O3) may be free of such decoherence sources.

Development of a Metallic Bilayer Liftoff Mask

TBMG-2531709/01/2016

A large variety of cryogenic detectors need to be fabricated on thin dielectric membranes in order to have high signal-to-noise attributes. Unfortunately, many of the etching processes used to define the detectors can roughen or even completely dissolve the membranes. These types of membrane damage degrade the detector performance and limit fabrication yield.

High Field Superconducting Magnets

TBMG-2516508/01/2016

This superconducting magnet developed at NASA Goddard Space Flight Center comprises a superconducting wire wound in adjacent turns about a mandrel to form the superconducting magnet; a thermally conductive potting material configured to fill interstices between the adjacent turns; and a voltage limiting device disposed across each end of the superconducting wire, and is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet. The thermally conductive potting material and the superconducting wire provide a path for dissipation of heat.

Method to Improve the Synthesis Process of High-Purity Bulk Multi-Element Compounds

TBMG-2425304/01/2016

Multi-element compounds have been used ubiquitously in various applications, including electronics, optics, opto-electronics, thermoelectrics, superconductivity, and the recently developed application of spintronics. Besides being the main components of some of these devices, the bulk form of these compounds is needed as a standard for fundamental property characterizations as well as the starting materials for thin-film deposition. Hence, the chemical purity and crystalline quality of these bulk compounds are critical for the applications.

High-Temperature Superconducting Bolometric Devices on Amorphous Silicon Nitride Membranes

TBMG-2346912/01/2015

There has been a great deal of interest in building bolometers from hightemperature superconductors due to their high transition temperatures and the associated ease of cooling. High-temperature superconducting (high Tc) bolometers are difficult to fabricate because the standard method of thermal isolation is not compatible with these materials. A method is described that allows a standard thermal isolation technique (using amorphous silicon nitride membranes) to be used with high-temperature superconductors.

Hybrid DC Circuit Breaker Based on Cryogenic Technique

07/01/2015

DC protection systems such as circuit breakers play a key enabling role for the DC power system in applications such as aviation, the power grid, and the like. Conventional electromagnetic circuit breakers are a mature technology. However, the large size and high response time make it unsuitable for an electrical system in aviation that requires fast response time. Compared with a mechanical circuit breaker, the solid-state circuit breaker based on high-power semiconductors can provide a fast response time to make the fault current fully controlled. The on resistance of the semiconductors creates high conduction loss, which leads to low efficiency. Therefore, a hybrid solution that combines both mechanical and solid-state technology is desired.

Multimode, Fiber-Coupled, Tungsten Silicide, Superconducting Nanowire Single-Photon Detector Array

12/01/2014

The superconducting nanowire single-photon detector (SNSPD) arrays created in this innovation were fabricated using a WSi nanowire process. A gold mirror layer is deposited on an oxidized silicon wafer, and amorphous-state WSi is sputtered from a compound target at a thickness of 5 nm. The WSi nanowire is embedded at the center of a three-layer vertical optical cavity consisting of two silica layers and a titanium oxide anti-reflective coating. The layer thicknesses were chosen, on the basis of simulations and measured material parameters, to optimize efficiency at the target communication wavelength of 1,550 nm, and to minimize the polarization dependence of the detector response.

Flexible Microstrip Circuits for Superconducting Electronics

TBMG-1873912/01/2013

Flexible circuits with superconducting wiring atop polyimide thin films are being studied to connect large numbers of wires between stages in cryogenic apparatus with low heat load. The feasibility of a full microstrip process, consisting of two layers of superconducting material separated by a thin dielectric layer on 5 mil (≈0.13 mm) Kapton sheets, where manageable residual stress remains in the polyimide film after processing, has been demonstrated. The goal is a 2-mil (≈0.051-mm) process using spin-on polyimide to take advantage of the smoother polyimide surface for achieving high-quality metal films. Integration of microstrip wiring with this polyimide film may require high-temperature bakes to relax the stress in the polyimide film between metallization steps.

Passivation of Flexible YBCO Superconducting Current Lead With Amorphous SiO2 Layer

TBMG-1744910/01/2013

Adiabatic demagnetization refrigerators (ADR) are operated in space to cool detectors of cosmic radiation to a few 10s of mK. A key element of the ADR is a superconducting magnet operating at about 0.3 K that is continually energized and de-energized in synchronism with a thermal switch, such that a piece of paramagnetic salt is alternately warm in a high magnetic field and cold in zero magnetic field. This causes the salt pill or refrigerant to cool, and it is able to suck heat from an object, e.g., the sensor, to be cooled. Current has to be fed into and out of the magnets from a dissipative power supply at the ambient temperature of the spacecraft. The current leads that link the magnets to the power supply inevitably conduct a significant amount of heat into the colder regions of the supporting cryostat, resulting in the need for larger, heavier, and more powerful supporting refrigerators. The aim of this project was to design and construct high-temperature superconductor (HTS

Ultra-Low Heat- Leak, High- Temperature Superconducting Current Leads for Space Applications

TBMG-1611904/01/2013

NASA Goddard Space Flight Center has a need for current leads used in an adiabatic demagnetization refrigerator (ADR) for space applications. These leads must comply with stringent requirements such as a heat leak of approximately 100 μW or less while conducting up to 10 A of electric current, from more than 90 K down to 10 K. Additionally, a length constraint of

Fabrication of a Cryogenic Bias Filter for Ultrasensitive Focal Plane

TBMG-1326204/01/2012

A fabrication process has been developed for cryogenic in-line filtering for the bias and readout of ultrasensitive cryogenic bolometers for millimeter and submillimeter wavelengths. The design is a microstripline filter that cuts out, or strongly attenuates, frequencies (10–50 GHz) that can be carried by wiring staged at cryogenic temperatures. The filter must have 100-percent transmission at DC and low frequencies where the bias and readout lines will carry signal. The fabrication requires the encapsulation of superconducting wiring in a dielectric-metal envelope with precise electrical characteristics. Sufficiently thick insulation layers with high-conductivity metal layers fully surrounding a patterned superconducting wire in arrayable formats have been demonstrated.

Hall Effect Measurements are Essential for Characterizing High Carrier Mobility in Materials

TBMG-1076708/01/2011

The Hall effect can be observed when the combination of a magnetic field through a sample and a current along the length of the sample create an electrical current perpendicular to both the magnetic field and the current, which in turn creates a transverse voltage perpendicular to both the field and the current. The underlying principle is the Lorentz force: the force on a point charge due to electromagnetic fields.

Finite-Element Simulations of Field and Current Distributions in Multifilament Superconducting Films

TBMG-884612/01/2010

The separation of high-temperature superconducting (HTS) tapes in filaments is a viable approach to reduce AC losses in HTS high-power applications, where AC currents and/or fields may be applied in addition to any DC field present. Methods such as mechanical, laser scribing, photolithography, or direct printing on buffered substrates using inkjet deposition have been used to create the filaments in the second-generation HTS coated conductors in order to reduce hysteretic losses. However, losses of the finely striated tapes can still be noticeably larger than predicted by analytical expressions, due to the addition of coupling currents or lack of field penetration, and such deviation tends to grow with increasing filament density. In order to reduce the magnetic coupling between filaments and the associated AC losses, an in-depth understanding of flux and current dynamics in the multifilamentary HTS, in realistic conditions, is required.

Magnesium Diboride Current Leads

TBMG-830008/01/2010

A recently discovered superconductor, magnesium diboride (MgB2), can be used to fabricate conducting leads used in cryogenic applications. Discovered to be superconducting in 2001, MgB2 has the advantage of remaining superconducting at higher temperatures than the previously used material, NbTi. The purpose of these leads is to provide 2 A of electricity to motors located in a 1.3 K environment. The providing environment is a relatively warm 17 K. Requirements for these leads are to survive temperature fluctuations in the 5 K and 11 K heat sinks, and not conduct excessive heat into the 1.3 K environment. Test data showed that each lead in the assembly could conduct 5 A at 4 K, which, when scaled to 17 K, still provided more than the required 2 A.

Robert Romanofsky, Senior Scientist, Antenna and Optical Systems Branch

TBMG-729302/01/2010

Dr. Robert Romanofsky has over 75 publications and holds five patents in the fields of microwave device technology, high-temperature superconductivity, and the use of thin ferroelectric films in microwave applications. A recipient of NASA’s Exceptional Service Medal, Exceptional Technology Achievement Medal, the Federal Executive Board “Wings of Excellence” award, and the Rotary National Stellar Space Award, he currently serves as senior engineer for the Antenna and Optical Systems Branch at the NASA Glenn Research Center where he works on advanced antenna systems designs.

Small Low-Temperature Thermometer With Nanokelvin Resolution

TBMG-TB-00707501/25/2010

The magnetic field is generated by permanent magnets instead of a solenoid. An improved high-resolution thermometer (HRT) for use in scientific experiments at temperatures <4 K has been developed. Like other, previously developed low-temperature HRTs, this device is based on the strong temperature dependence of the magnetization of a paramagnetic salt exposed to a magnetic field. However, in comparison with other paramagnetic-salt HRTs, this one is smaller and less massive; hence, it is denoted "sHRT" - short for "small HRT."

Magnetic-Field-Tunable Superconducting Rectifier

TBMG-634912/01/2009

Superconducting electronic components have been developed that provide current rectification that is tunable by design and with an externally applied magnetic field to the circuit component. The superconducting material used in the device is relatively free of pinning sites with its critical current determined by a geometric energy barrier to vortex entry. The ability of the vortices to move freely inside the device means this innovation does not suffer from magnetic hysteresis effects changing the state of the superconductor. The invention requires a superconductor geometry with opposite edges along the direction of current flow. In order for the critical current asymmetry effect to occur, the device must have different vortex nucleation conditions at opposite edges. Alternative embodiments producing the necessary conditions include edges being held at different temperatures, at different local magnetic fields, with different current-injection geometries, and structural differences

Some Advances in High-Temperature Superconductor Coatings

TBMG-477702/01/2008

Several advances were made in a program focused on the science and technology of high-temperature superconductors [especially yttrium barium copper oxide (“YBCO”)] deposited on normal electrical conductors. This program was part of a continuing effort to develop superconductor-coated normal conductors for use in electric-power systems of interest to the Air Force.

Techniques for Connecting Superconducting Thin Films

TBMG-116211/01/2006

Several improved techniques for connecting superconducting thin films on substrates have been developed. The techniques afford some versatility for tailoring the electronic and mechanical characteristics of junctions between superconductors in experimental electronic devices. The techniques are particularly useful for making superconducting or alternatively normally conductive junctions (e.g., Josephson junctions) between patterned superconducting thin films in order to exploit electron quantum-tunneling effects.

Using Quasiparticle Poisoning To Detect Photons

TBMG-645903/01/2006

According to a proposal, a phenomenon associated with excitation of quasiparticles in certain superconducting quantum devices would be exploited as a means of detecting photons with exquisite sensitivity. The phenomenon could also be exploited to perform medium-resolution spectroscopy. The proposal was inspired by the observation that Coulomb blockade devices upon which some quantum logic gates are based are extremely sensitive to quasiparticles excited above the superconducting gaps in their leads. The presence of quasiparticles in the leads can be easily detected via the charge states. If quasiparticles could be generated in the leads by absorption of photons, then the devices could be used as very sensitive detectors of electromagnetic radiation over the spectral range from xrays to submillimeter waves.

Making Wide-IF SIS Mixers With Suspended Metal-Beam Leads

TBMG-23009/01/2005

A process that employs silicon-on-insulator (SOI) substrates and silicon (Si) micromachining has been devised for fabricating wide intermediate frequency band (wide-IF) superconductor/ insulator/ superconductor (SIS) mixer devices that result in suspended gold beam leads used for radio-frequency grounding. The mixers are formed on 25-µm-thick silicon membranes. They are designed to operate in the 200 to 300 GHz frequency band, wherein wide-IF receivers for tropospheric- chemistry and astrophysical investigations are necessary. The fabrication process can be divided into three sections:

Making AlNx Tunnel Barriers Using a Low-Energy Nitrogen-Ion Beam

TBMG-22909/01/2005

A technique based on accelerating positive nitrogen ions onto an aluminum layer has been demonstrated to be effective in forming thin (<2 nm thick) layers of aluminum nitride (AlNx) for use as tunnel barriers in Nb/Al-AlNx/Nb superconductor/ insulator/ superconductor (SIS) Josephson junctions. AlNx is the present material of choice for tunnel barriers because, to a degree greater than that of any other suitable material, it offers the required combination of low leakage current at high current density and greater thermal stability.

Cryogenic High-Sensitivity Magnetometer

TBMG-29806/01/2005

A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10-16 Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10-10 Tesla).

Cryogenic High-Sensitivity Magnetometer

TBMG-58106/01/2005

A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10-16 Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10-10 Tesla).

Magnetocaloric Pumping of Liquid Oxygen

TBMG-2924102/01/2004

As noted in the previous article, the field-induced force density on a magnetic fluid is proportional to the magnetic susceptibility times the gradient of the magnetic field squared. The direction of the force is towards increasing magnetic field (positive gradient). Applying a magnetic field to a magnetic fluid will result in a force from all directions towards the location of peak field. Since the magnetic field is conservative and there are no magnetic monopoles, the net field-induced force on any fluid of constant susceptibly will be zero. The only manner to obtain a nonzero net field-induced force is to vary the susceptibility of the fluid. At the gas/liquid interface of liquid oxygen, the susceptibility varies drastically, and the exploitation of the resultant large net forces has been detailed in the previous article, "Pumping Liquid Oxygen With Pulsed Magnetic Fields" (KSC-12284).

Concept for Utilizing Full Areas of STJ Photodetector Arrays

TBMG-309004/01/2002

A method of designing improved monolithic planar arrays of superconducting tunnel junctions (STJs) for use as photodetectors has been conceived. These arrays would be suitable for detecting images at low light levels. They are for operation in the individual-photon- counting regime; they are used not only to detect the arrival of individual photons but also to measure the individual photon energies. As such, the STJ arrays would be compact sensors that would perform the functions now performed by bulkier equipment in the form of photomultipliers and spectrometers. Eventually, it should be possible to use STJ arrays for such demanding applications as simultaneous imaging and spectroscopy of faint astronomical objects.

"Set and Hold With Power Off" Cryogenic Actuators

TBMG-682805/01/2000

Magnetostrictive actuators that would hold their displacements with power turned off have been proposed for use at temperatures from about 10 to about 77 K. Such "set and hold with power off" actuators are attractive for effecting fine position adjustments in cryogenic scientific instruments, wherein significant amounts of heat would be released and could disturb instrument operation if it were necessary to apply power continually to maintain actuator displacements.

Improved Fabrication of YBa2Cu3O7 —x Superconductors

TBMG-680904/01/2000

An improved method of manufacturing high-temperature superconductors of general composition YBa2Cu3O7— x and various grain structures has been devised. This method involves mixing, pressing, and heating of Y2O3, CuO, and Ba(NO3)2 powders. This method is easier than an older method that involved mixing and sintering of Y2O3, CuO, and BaCO3 powders followed by repeated grinding and sintering, followed by pressing to final size and shape.

Tunable HTS/Ferroelectric Microstrip Band-Pass Filters

TBMG-671101/01/2000

Electrically tunable microstrip two-pole band-bass filters for a center frequency near 19 GHz and a 4-percent bandwidth have been designed, fabricated, and demonstrated to be functional. These filters are suitable for use in the front ends of K-band communication receivers that operate at low temperatures.

Improved Magnetostrictive Valve for Use at Low Temperature

TBMG-2981408/01/1999

An improved magnetostrictive valve for remotely controlling a flow of liquid helium has been developed. Heretofore, flows of liquid helium have been controlled by use of valves with mechanical or gas connections to actuators in warmer locations. The connections act as heat-leak paths. In contrast, the design of the present valve is optimized for operation at liquid-helium temperature (below 4.2 K), so that the entire valve can be maintained at or slightly above liquid-helium temperature to minimize leakage of heat into the liquid helium.

Push/Pull Magnetostrictive Linear Actuator

TBMG-2980708/01/1999

A proposed "kinematic inchworm"-type linear actuator would move a mass as large as 2 kg along rails, with lengthwise position controllable in increments as small as 50 nm. The actuator could be operated in microgravity or in normal Earth gravitation and at any temperature from ambient down to cryogenic. The actuator could be used, for example, to position an optical assembly precisely on a long interferometer arm, as a translation stage for a scanning tunneling microscope, or as a translation stage for inspecting integrated-circuit chips.

Determining Superconductor Inhomogeneity at Room Temperature

TBMG-2991707/01/1999

A technique for determining inhomogeneities in a specimen of a high-critical-temperature superconductor involves scanning a small eddy-current probe over a flat surface of the specimen at room temperature while monitoring the inductance of the probe. In contrast, older techniques for obtaining the same or similar information involve cooling the specimen below its superconducting-transition critical temperature (TC), with attendant difficulty and cost of operating a cryogenic apparatus.

Active Homopolar Magnetic Bearing

TBMG-2999005/01/1999

A report presents information on an earlier work on active magnetic bearings with high-critical-temperature superconducting coils. To recapitulate, the device is a homopolar radial-type active magnetic bearing with a bias coil and control coils made of a high-critical-temperature superconductor. The report discusses major features of the design and operation of the bias and control coils, measurements of ac power losses in the control coils, and results of experiments in which the device was operated at the temperature of liquid nitrogen. The experimental findings and conclusions stated in the report are nearly identical to those noted earlier. One particularly notable conclusion is that ac losses appeared to be related to coil inductances and that it may therefore be possible to reduce these losses by winding the control coils from twisted, multifilamentary forms of the superconductor.

SQUID-Based Asymmetric Planar Gradiometer

TBMG-3215707/01/1998

Berkeley Laboratory researchers have demonstrated a novel superconducting gradiometer that helps to reduce ambient magnetic field noise generated by relatively distant sources in favor of tiny magnetic signals generated by a local source. This is another step toward the operation of SQUID-based instruments in an unshielded environment: for example, for the detection of magnetic signals produced by the human heart or brain.

Polyimide Passivation for Making High-Tc Josephson Junctions

TBMG-3214301/01/1998

Passivation by coating with OCG285 (or equivalent) polyimide at critical steps of fabrication has been found to enhance the quality of tapered edges in high-critical-temperature (high-Tc) superconductor/normal-conductor/superconductor (SNS) Josephson junctions. In comparison with Josephson junctions that are nominally identical except for having been fabricated without such passivation, those fabricated with polyimide passivation exhibit cleaner and smoother edges and, consequently, smaller differences among the resistances and critical currents of individual junctions.

Adiabatic Demagnetisation Refrigerators for Space Applications

94127906/01/1994

We show that the space prohibitive laboratory adiabatic demagnetization refrigerator properties of high magnetic field and a <2K environment (provided by a bath of liquid He4) can be alleviated, without a significant decrease in operational efficiency, through the use of a 2 or 3 salt pill refrigerator rather then the classical single salt pill design. The additional salt pills providing intermediate cooling stages, enabling operation from a 4K environment which can be provided by a single mechanical cooler. For such ADRs the minimum magnetic field required is 2 and 1 Tesla for the 2 and 3 salt pill cases respectively. Such low magnetic fields allow the possible use of permanent and high temperature mechanically cooled superconducting magnets, avoiding the danger of quenching of the superconducting magnet. We conclude that such ADRs offer a long orbital life time, high efficiency means of sub Kelvin cooling.

Hepburn, I. D., Smith, A., Davenport, I.

Recent Advances in High-Temperature Superconductor Wire Fabrication and Applications Development

92927108/03/1992

In this paper, recent advances in fabrication of high-temperature superconductor wires are summarized and detailed discussion is provided on developments in near- and intermediate-term applications. Near-term applications, using presently obtainable current densities, include liquid-nitrogen depth sensors, cryostat current leads, and magnetic bearings. Intermediate-term applications, using current densities expected to be available in the near future, include fault-current limiters and short transmission lines.

Hull, John R., Uherka, Kenneth L.

Superconducting Maglev on the New Test Line and Related Technology Development in Japan

91162108/01/1991

With the Government approval of the construction plan of an about 43 km long new maglev test line in Yamanashi Prefecture, the superconducting maglev development in Japan has stepped into a new phase. This paper updates the progress in the related research and development on the Yamanashi Maglev Test Line.

Takeda, Hiroshi

Development of Superconducting Maglev in Japan: Present State and Future Perspective

90147808/01/1990

The Railway Technical Research Institute has assumed responsibility for Maglev development from the defunct JNR which has run the program since its inception. At the Miyazaki Test Track, test runs of the MLU 002 test vehicle are continuing, while the Ministry of Transport has authorized a new test track about 43 km long. The funding was approved in June as a government subsidy. This paper reviews the latest achievements at the Miyazaki Test Track and the future prospects of Maglev development (Photo 1).

Takeda, Hiroshi

Experimental Performance of Model Liquid Hydrogen Space Tankage with a Compressible Super Insulation

62036401/01/1962

Model tankage for a space vehicle has been insulated with a compressible super insulation enclosed within a vacuum tight flexible plastic shell. To simulate the prelaunch condition, the 9 ft long model has been tested with liquid hydrogen in its propellant tank, and the insulation system compressed by an external load of 1 atm. The thermal conductivity of the compressed insulation was 47 × 10-5 Btu/hr ft deg R, a value generally considered better than required. Simulation of space conditions resulted in substantial recovery of the normal uncompressed insulation performance. Data are included concerning the evacuation of the insulation and recovery of the insulation system. Temperature measurements in the vicinity of the intermediate bulkhead of this two-compartment tank are included.

Murto, P. J., Lindquist, C. R., Niendorf, L R.

A New Technology - Solid State Physics

58024301/01/1958

Ference, Michael

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