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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

Solid Hydrogen Experiments for Atomic Propellants

This paper illustrates experiments that were conducted on the formation of solid hydrogen particles in liquid helium. Solid particles of hydrogen were frozen in liquid helium, and observed with a video camera. The solid hydrogen particle sizes, their molecular structure transitions, and their agglomeration times were estimated. article sizes of 1.8 to 4.6 mm (0.07 to 0. 18 in.) were measured. The particle agglomeration times were 0.5 to 11 min, depending on the loading of particles in the dewar. These experiments are the first step toward visually characterizing these particles, and allow designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

Palaszewski, Bryan↗
NASA NTRS2002

Solid Hydrogen Experiments for Atomic Propellants: Image Analyses

This paper presents the results of detailed analyses of the images from experiments that were conducted on the formation of solid hydrogen particles in liquid helium. Solid particles of hydrogen were frozen in liquid helium, and observed with a video camera. The solid hydrogen particle sizes, their agglomerates, and the total mass of hydrogen particles were estimated. Particle sizes of 1.9 to 8 mm (0.075 to 0.315 in.) were measured. The particle agglomerate sizes and areas were measured, and the total mass of solid hydrogen was computed. A total mass of from 0.22 to 7.9 grams of hydrogen was frozen. Compaction and expansion of the agglomerate implied that the particles remain independent particles, and can be separated and controlled. These experiment image analyses are one of the first steps toward visually characterizing these particles, and allow designers to understand what issues must be addressed in atomic propellant feed system designs for future aerospace vehicles.

Palaszewski, Bryan↗
NASA NTRS2000

Solid Hydrogen Formed for Atomic Propellants

Several experiments on the formation of solid hydrogen particles in liquid helium were recently conducted at the NASA Glenn Research Center at Lewis Field. The solid hydrogen experiments are the first step toward seeing these particles and determining their shape and size. The particles will ultimately store atoms of boron, carbon, or hydrogen, forming an atomic propellant. Atomic propellants will allow rocket vehicles to carry payloads many times heavier than possible with existing rockets or allow them to be much smaller and lighter. Solid hydrogen particles are preferred for storing atoms. Hydrogen is generally an excellent fuel with a low molecular weight. Very low temperature hydrogen particles (T < 4 K) can prevent the atoms from recombining, making it possible for their lifetime to be controlled. Also, particles that are less than 1 mm in diameter are preferred because they can flow easily into a pipe when suspended in liquid helium. The particles and atoms must remain at this low temperature until the fuel is introduced into the engine combustion (or recombination) chamber. Experiments were, therefore, planned to look at the particles and observe their formation and any changes while in liquid helium.

Palaszewski, Bryan A.↗
NASA NTRS1986

Transferring superfluid helium in space

A simple thermodynamic model of a transfer system for resupplying liquid helium in space is presented, with application to NASA projects including the Space Infrared Telescope Facility, the Large Deployable Reflector, and the Hubble Space Telescope. The relations between different thermodynamic regimes that can be expected in the transfer line are used to study the relative efficiencies of various possible transfer techniques. Low heat leak into the transfer line, particularly at point sources such as the coupling, is necesssary for efficient transfer of liquid helium, and proper selection of supply tank temperature is important during helium resupply.

Kittel, Peter↗
NASA NTRSDate not supplied

On-Orbit Performance of the Adiabatic Demagnetization Refrigerator on XRISM

The X-ray Imaging and Spectroscopy Mission (XRISM) observatory was launched on Sep 7, 2023 from Tanegashima Space Center in Japan. Resolve, one its two instruments, performs high-resolution spectroscopy in the soft x-ray band (0.2-13 keV) using a 6x6 microcalorimeter array. The array cooled to 50 mK by a 3-stage ADR, which is linked to both a liquid helium dewar (at <1.2 K) and a Joule-Thomson (JT) cryocooler operating at <4.5 K. While liquid helium is present, two of the ADR stages provide detector cooling at 50 mK and auxiliary cooling to 0.5 K to intercept some parasitic heat loads, while rejecting waste heat to the helium. Once the helium is exhausted, Resolve enters a cryogen-free mode in which all three ADR stages are operated to provide detector cooling at 50 mK and to continuously cool the helium tank to 1.4 K. In this mode, waste heat is rejected to the JT cryocooler. Cryogen-free operation can be sustained as long as the JT and other cryocoolers remain fully operational. At launch, the helium tank contained approximately 35.6 liters of liquid. Within a few days, the helium cooled below 1.15 K, with an estimated 35.0 liters remaining. With an expected time average heat load of 0.68 mW, the helium lifetime was projected to exceed 4 years, but measurements of He volume on orbit suggest a significantly longer lifetime. Details of the ADR’s design and performance are presented.

x-ray astromony↗
DOE OSTI2020

Conceptual Design of a Conduction-Cooled Superconducting Undulator

In superconducting undulators (SCUs) that are currently operating at the Advanced Photon Source, the undulator magnets are indirectly cooled with liquid helium penetrating through channels in the magnet cores. The liquid helium is stored in a tank that is cooled by cryocoolers. However, a cryogen-free version of a superconducting undulator in which the undulator magnets are conduction-cooled is also possible, as has been realized in the SCUs developed at ANKA. We are currently working on a conceptual design of a conduction-cooled planar superconducting undulator. The measured load lines of cryocoolers and the measured thermal conductance of various thermal links are used in the thermal analysis. Also, various materials for the undulator magnet cores are being considered. This paper reports the thermal design of a conduction-cooled planar SCU.

cryocooler↗
NASA NTRS1971

High resolution Fouier transform spectrometer Serial No. 091002: Instruction manual

A description of the spectrometer and procedures for its operation, maintenance, alignments, adjustments, and control functions are presented. The interferometer spectrometer is a modified Model 296 capable of 0.5/cm resolution over the spectral region of 5 to 15 microns configured for operation with the optical head at a temperature of approximately 80 K. Details are given on the optical system and the electronic circuits. The detector used with the optical head is mercury doped germanium kept at a temperature of about 4 K by means of liquid helium. Electronic schematics, and instruction manuals for handling the liquid helium dewars, tape recorder for analog outputs, and playback console are included.

Source record↗
NASA NTRS2002

Operating SIRTF for maximum lifetime

The instruments of the Space Infrared Telescope Facility (SIRTF) are cooled directly by liquid helium, while the optical system is cooled by helium vapor. The greater the power dissipation into the liquid helium, the more vapor is produced, and the colder the telescope. Observations at shorter wavelengths do not require telescope temperatures as low as those required at longer wavelengths. By taking advantage of this, it may be possible to extend the helium and mission lifetime by 10% or even 20%.

cryogenics↗
NASA NTRS1976

Experiments on the properties of superfluid helium in zero gravity

The paper describes a research program designed to study the behavior of superfluid liquid helium in low and zero gravity in order to determine the properties which are critically important to its use as a stored cryogen for cooling scientific instruments aboard spacecraft for periods up to several months. The experiment program consists of a series of flights of an experiment package on a free-fall trajectory both on an aircraft and on a rocket. The objectives are to study thickness of thin films of helium as a function of acceleration, heat transfer in thin films, heat transfer across copper-liquid helium interfaces, fluid dynamics of bulk helium in high and low accelerations and under various conditions of rotations, alternate methods of separation of liquid and vapor phases and of efficient venting of the vapor, and undesirable thermomechanical oscillations in the vent pipes. Preliminary results from aircraft tests are discussed.

Mason, P.↗
NASA NTRS1993

Performance of ceramic superconductors in magnetic bearings

Magnetic bearings are large-scale applications of magnet technology, quite similar in certain ways to synchronous machinery. They require substantial flux density over relatively large volumes of space. Large flux density is required to have satisfactory force density. Satisfactory dynamic response requires that magnetic circuit permeances not be too large, implying large air gaps. Superconductors, which offer large magnetomotive forces and high flux density in low permeance circuits, appear to be desirable in these situations. Flux densities substantially in excess of those possible with iron can be produced, and no ferromagnetic material is required. Thus the inductance of active coils can be made low, indicating good dynamic response of the bearing system. The principal difficulty in using superconductors is, of course, the deep cryogenic temperatures at which they must operate. Because of the difficulties in working with liquid helium, the possibility of superconductors which can be operated in liquid nitrogen is thought to extend the number and range of applications of superconductivity. Critical temperatures of about 98 degrees Kelvin were demonstrated in a class of materials which are, in fact, ceramics. Quite a bit of public attention was attracted to these new materials. There is a difficulty with the ceramic superconducting materials which were developed to date. Current densities sufficient for use in large-scale applications have not been demonstrated. In order to be useful, superconductors must be capable of carrying substantial currents in the presence of large magnetic fields. The possible use of ceramic superconductors in magnetic bearings is investigated and discussed and requirements that must be achieved by superconductors operating at liquid nitrogen temperatures to make their use comparable with niobium-titanium superconductors operating at liquid helium temperatures are identified.

Kirtley, James L., Jr.↗
DOE OSTI2020

Cryocooled cold trap system for the SuperCDMS dilution refrigerator

Operating 6,800 feet underground at the SNOLAB facility in Sudbury, Ontario, Canada, the dilution refrigerator-cooled SuperCDMS SNOLAB (Super Cryogenic Dark Matter Search at the Sudbury Neutrino Observatory Laboratory) experiment has been designed for maximum cryogenic up-time and remote operations. A key element in achieving these goals is a pair cold traps in the helium circulation stream of the dilution refrigerator; the first operating near liquid nitrogen temperatures and the second operating near liquid helium temperatures. Previous experience with the CDMS experiment, located underground at the Soudan Under-ground Laboratory, has given significant operational experience with dilution refrigerator cold traps and has solidified the demand of a system of dual cold traps. Unlike the CDMS-era system, the new SuperCDMS system will feature a cryocooler powered liquid nitrogen re-liquefying system (as opposed to regular under-ground re-filling of cold trap dewars using portable nitrogen dewars) and a cryogen-free 4 K cold trap, which eliminates the need for a bath of liquid helium.

43 PARTICLE ACCELERATORS↗
NASA NTRS1972

Performance of a 12-coil superconducting bumpy torus magnet facility

The bumpy torus facility consists of 12 superconducting coils, each 19 cm i.d. and capable of 3.0 teslas on their axes. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Final shakedown tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The facility is now ready for use as a plasma physics research facility. A maximum magnetic field on the magnetic axis of 3.23 teslas was held for a period of more than sixty minutes without a coil normalcy. The design field was 3.00 teslas. The steady-state liquid helium boil-off rate was 87 liters per hour of liquid helium without the coils charged. The coil array was stable when subjected to an impulsive loading, even with the magnets fully charged. When the coils were charged to a maximum magnetic field of 3.35 teslas, the system was driven normal without damage.

Roth, J. R.↗
NASA NTRS1993

X-Band Ultra-Low Noise Maser Amplifier Performance

Noise temperature measurements of an 8440 MHz ultra-low noise maser amplifier (ULNA) have been performed at sub-atmospheric, liquid helium temperatures. The traveling wave maser operated while immersed in a liquid helium bath. The lowest input noise temperature measured was 1.23 plus or minus 0.16 K at a physical temperature of 1.60 kelvin. At this physical temperature the observed gain per unit length of ruby was 4.6 dB/cm, and the amplifier had a 3 dB-bandwidth of 76 MHz.

ultra-low noise maser amplifier X-band maser syste↗
NASA NTRS2013

Recirculating 1-K-Pot for Pulse-Tube Cryostats

A paper describes a 1-K-pot that works with a commercial pulse tube cooler for astrophysics instrumentation testbeds that require temperatures <1.7 K. Pumped liquid helium-4 cryostats were commonly used to achieve this temperature. However, liquid helium-4 cryostats are being replaced with cryostats using pulse tube coolers. The closed-cycle 1K-pot system for the pulse tube cooler requires a heat exchanger on the pulse tube, a flow restriction, pump-out line, and pump system that recirculates helium-4. The heat exchanger precools and liquefies helium- 4 gas at the 2.5 to 3.5 K pulse tube cold head. This closed-cycle 1-K-pot system was designed to work with commercially available laboratory pulse tube coolers. It was built using common laboratory equipment such as stainless steel tubing and a mechanical pump. The system is self-contained and requires only common wall power to operate. The lift of 15 mW at 1.1 K and base temperature of 0.97 K are provided continuously. The system can be scaled to higher heat lifts of .30 to 50 mW if desired. Ground-based telescopes could use this innovation to improve the efficiency of existing cryo

Paine, Christopher T.↗
NASA NTRS1991

Gravity jitter excited cryogenic liquid slosh waves in microgravity environment

The dynamical behavior of fluids, in particular the effect of surface tension on partially-filled rotating fluids (cryogenic liquid helium and helium vapor) in a full-scale Gravity Probe-B Spacecraft liquid helium container tank without probe imposed by various frequencies of gravity jitter have been investigated. Results disclose the conditions for the excitation of large amplitude slosh waves which should be avoided in the design of cryogenic liquid propellant system.

Hung, R. J.↗
NASA NTRS1985

Design of Cryocoolers for Microwatt Superconducting Devices

The primary applications of the cryocoolers are for cooling various Josephson devices such as SQUID magnetometers and amplifiers, voltage standards, and microwave mixers and detectors. The common feature of these devices is their extremely low inherent bias power requirement, of the order of 10/1 W per junction. This provides the possibility of designing compact, low-power cryocoolers for these applications. Several concepts were explored and a number of laboratory model cryocoolers were built. These include low-power nonmagnetic regenerative machines of the Stirling or Gifford-McMahon type, three or four-stage Joule-Thomson machines, liquid-helium dewars with integral small cryocoolers to reduce the evaporation rate, and liquid-helium dewars with integral continuously or intermittently operated small helium liquefiers to permit operation of cryogenic devices for indefinite time periods.

Zimmerman, J. E.↗
NASA NTRS1994

X-band ultralow-noise maser amplifier performance

Noise temperature measurements of an 8440-MHz ultralow noise maser amplifier (ULNA) have been performed at subatmospheric, liquid-helium temperatures. The traveling-wave maser was operated while immersed in a liquid helium bath. The lowest input noise temperature measured was 1.43 +/- 0.16 K at a physical temperature of 1.60 K. At this physical temperature, the observed gain per centimeter of ruby was 4.9 dB/cm. The amplifier had a 3-dB bandwidth of 76 MHz.

Glass, G. W.↗