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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Simple Spreadsheet Thermal Models for Cryogenic Applications

Self consistent circuit analog thermal models that can be run in commercial spreadsheet programs on personal computers have been created to calculate the cooldown and steady state performance of cryogen cooled Dewars. The models include temperature dependent conduction and radiation effects. The outputs of the models provide temperature distribution and Dewar performance information. these models have been used to analyze the SIRTF Telescope Test Facility (STTF). The facility has been brought on line for its first user, the Infrared Telescope Technology Testbed (ITTT), for the Space Infrared Telescope Facility (SIRTF) at JPL. The model algorithm as well as a comparison between the models' predictions and actual performance of this facility will be presented.

spreadsheet thermal model cryogenic↗
NASA NTRS1994

(abstract) Simple Spreadsheet Thermal Models for Cryogenic Applications

Self consistent circuit analog thermal models, that can be run in commercial spreadsheet programs on personal computers, have been created to calculate the cooldown and steady state performance of cryogen cooled Dewars. The models include temperature dependent conduction and radiation effects. The outputs of the models provide temperature distribution and Dewar performance information. These models have been used to analyze the Cryogenic Telescope Test Facility (CTTF). The facility will be on line in early 1995 for its first user, the Infrared Telescope Technology Testbed (ITTT), for the Space Infrared Telescope Facility (SIRTF) at JPL. The model algorithm as well as a comparison of the model predictions and actual performance of this facility will be presented.

cryogenic thermal model cryostat SIRTF↗
NASA NTRS1990

Liquid helium Dewar for one meter mirror testing

The NASA Ames Research Center has developed a baseline design for a One Meter Cryogenic Optical Test Facility (OMF) incorporating a liquid helium Dewar for cryogenic optical testing of one-meter-class mirrors, principally the Space Infrared Telescope Facility (SIRTF) primary mirror. The primary requirements for the test facility are as follows: (1) the facility must be capable of interferometrically testing any mirror, positioned face-up or face-down, with a diameter less than 1.5 meters and a radius of curvature from 1.5 to 5.5 meters; (2) the facility must achieve and maintain, for 24 hours, a mirror temperature of 4 K with a maximum radiative heat load of less than 500 mW to the mirror, using stored liquid helium and liquid nitrogen; (3) the facility must include a vibration-isolated metrology structure between the test mirror and an external interferometer, and (4) the facility must be operated by two persons and a test, starting from the mounting of a mirror to the removal of a mirror, must be conducted within one week.

Sarver, George L., III↗
NASA NTRS1986

Study of an all SFHE SIRTF cryogenic system

The Space Infrared Telescope Facility (SIRTF) is a superfluid helium cooled, 85-cm telescope with three infrared instruments at the focal plane. SIRTF will establish in space a long-term-maintainable infrared observatory for the region of 2-700 microns. The cryogenic system can be designed to last up to six years with 1280 kg of superfluid, and can function in either a 28.5 deg or 98 deg inclination orbit by exchanging the sunshade. The lifetime is primarily a function of instrument heat load rather than parasitic heat to the cryogen system.

Urbach, A. R.↗
NASA NTRS1985

Orbital resupply of liquid helium

The ability to resupply scientific instruments in orbit with liquid helium would greatly enhance several planned missions. These missions include the SIRTF (Space Infrared Telescope Facility), the LDR (Large Deployable Reflector), the GP-B (Gravity Probe - B), and include individual instruments on the HST (Hubble Space Telescope), and on the AXAF (Advanced X-ray Astrophysics Facility). Resupply in orbit would extend the lifetimes of these missions without the difficulties, the delays, and the costs that are associated with retrieving the system, resupplying these systems on the ground, and relaunching. This is especially true of systems, such as the LDR, that are assembled in space and thus would be difficult to return to earth. This paper presents a conceptual design of a Helium Resupply System (HERS) and a discussion of the transfer efficiency.

Kittel, P.↗
NASA NTRS1988

The infrared spectrograph during the SIRTF pre-definition phase

A test facility was set up to evaluate back-illuminated impurity band detectors constructed for an infrared spectrograph to be used on the Space Infrared Telescope Facility (SIRTF). Equipment built to perform the tests on these arrays is described. Initial tests have been geared toward determining dark current and read noise for the array. Four prior progress reports are incorporated into this report. They describe the first efforts in the detector development and testing effort; testing details and a new spectrograph concept; a discussion of resolution issues raised by the new design; management activities; a review of computer software and testing facility hardware; and a review of the preamplifier constructed as well as a revised schematic of the detector evaluation facility.

Houck, James R.↗
NASA NTRS1995

Space Studies Board Annual Report 1994

The following summaries of major reports are presented: (1) 'Scientific Opportunities in the Human Exploration of Space;' (2) 'A Space Physics Paradox;' (3) 'An Integrated Strategy for the Planetary Sciences;' and (4) 'ONR (Office of Naval Research) Research Opportunities in Upper Atmospheric Sciences.' Short reports on the following topics are also presented: life and microgravity sciences and the Space Station Program, the Space Infrared Telescope Facility and the Stratospheric Observatory for infrared astronomy, the Advanced X-ray Astrophysics Facility and Cassini Saturn Probe, and the utilization of the Space Station.

Source record↗
NASA NTRS2007

Pointing History Engine for the Spitzer Space Telescope

The Pointing History Engine (PHE) is a computer program that provides mathematical transformations needed to reconstruct, from downlinked telemetry data, the attitude of the Spitzer Space Telescope (formerly known as the Space Infrared Telescope Facility) as a function of time. The PHE also serves as an example for development of similar pointing reconstruction software for future space telescopes. The transformations implemented in the PHE take account of the unique geometry of the Spitzer telescope-pointing chain, including all data on relative alignments of components, and all information available from attitude-determination instruments. The PHE makes it possible to coordinate attitude data with observational data acquired at the same time, so that any observed astronomical object can be located for future reference and re-observation. The PHE is implemented as a subroutine used in conjunction with telemetry-formatting services of the Mission Image Processing Laboratory of NASA s Jet Propulsion Laboratory to generate the Boresight Pointing History File (BPHF). The BPHF is an archival database designed to serve as Spitzer s primary astronomical reference documenting where the telescope was pointed at any time during its mission.

Bayard, David↗
NASA NTRS1991

Space astronomical telescopes and instruments; Proceedings of the Meeting, Orlando, FL, Apr. 1-4, 1991

The present volume on space astronomical telescopes and instruments discusses lessons from the HST, telescopes on the moon, future space missions, and mirror fabrication and active control. Attention is given to the in-flight performance of the Goddard high-resolution spectrograph of the HST, the initial performance of the high-speed photometer, results from HST fine-guidance sensors, and reconstruction of the HST mirror figure from out-of-focus stellar images. Topics addressed include system concepts for a large UV/optical/IR telescope on the moon, optical design considerations for next-generation space and lunar telescopes, the implications of lunar dust for astronomical observatories, and lunar liquid-mirror telescopes. Also discussed are space design considerations for the Space Infrared Telescope Facility, the Hubble extrasolar planet interferometer, Si:Ga focal-plane arrays for satellite and ground-based telescopes, microchannel-plate detectors for space-based astronomy, and a method for making ultralight primary mirrors.

Bely, Pierre Y.↗
NASA NTRS1991

The Next Century Astrophysics Program

The Astrophysics Division within the NASA Office of Space Science and Applications (OSSA) has defined a set of major and moderate missions that are presently under study for flight sometime within the next 20 years. These programs include the: Advanced X Ray Astrophysics Facility; X Ray Schmidt Telescope; Nuclear Astrophysics Experiment; Hard X Ray Imaging Facility; Very High Throughput Facility; Gamma Ray Spectroscopy Observatory; Hubble Space Telescope; Lunar Transit Telescope; Astrometric Interferometer Mission; Next Generation Space Telescope; Imaging Optical Interferometer; Far Ultraviolet Spectroscopic Explorer; Gravity Probe B; Laser Gravity Wave Observatory in Space; Stratospheric Observatory for Infrared Astronomy; Space Infrared Telescope Facility; Submillimeter Intermediate Mission; Large Deployable Reflector; Submillimeter Interferometer; and Next Generation Orbiting Very Long Baseline Interferometer.

Swanson, Paul N.↗
NASA NTRS2001

The Mid and Far IR Universe and Facilities To See It

Although half the luminosity of the universe appears in the band from 20-450 $\mu$m, almost nothing is known about the sources of this radiation. Moreover, many molecules, atoms, and ions of astrophysical interest have some of their strongest lines in this wavelength range. Now Infrared Astronomy Satellite (IRAS) and ISO have flown, Space Infrared Telescope Facility (SIRTF) is nearly ready, SOFIA is under construction, and NGST, ALMA, Herschel, Planck, and a dozen 8 m and a 25 m ground-based visible/near IR telescopes could all be operational by the end of decade. Nevertheless, the mid and far IR region will still not have telescopes that are comparable to neighboring bands in energy sensitivity or angular resolution, despite these many advances. What scientific questions will still be open, and what instrumentation will be required? We anticipate that cold filled-aperture telescopes operating out to 100 $\mu$m and cold imaging interferometers, operating out to about 450 $\mu$m in space could be very powerful, using direct detection rather than heterodyne systems. I will give a brief overview of the scientific questions that may still be open, the main factors governing the choice of equipment, and the technological developments that would be required to actually build and use these new facilities.

Mather, John C.↗
NASA NTRS1990

BASG thermomechanical pump helium 2 transfer tests

The purpose of the effort described was to perform experiments and calculations related to using a thermomechanical pump in the space-based resupply of the Space Infrared Telescope Facility (SIRTF) with Helium 2. Thermomechanical (fountain effect) pumps have long been suggested as a means for pumping large quantities of Helium 2. The unique properties of Helium 2 have made it useful for cooling space instruments. Several space science missions, including SIRTF, are now being planned which would benefit greatly from on-orbit resupply of Helium 2. A series of experiments were performed to demonstrate that large volumes of Helium 2 can be transferred with a thermomechanical pump at high flow rates and at high efficiency from one dewar to another through valves and lines that are similar to the plumbing arrangement that would be necessary to accomplish such a transfer on-orbit. In addition, temperature, pressure, and flow rate data taken during the tests were used to verify and refine a computer model which was developed.

Mills, G. L.↗
NASA NTRS1995

(abstract) Wide Dynamic Range Porous Plug and Vent Line for SIRTF

The most recent approach to the Space Infrared Telescope Facility (SIRTF) uses a new design concept in which the telescope is launched warm and subsequently cooled to operating temperture on orbit. At launch the cryostat is at 2 K and the telescope is at room temperature. Cooldown of the telescope will be accomplished initially through radiation to space. Final cooldown to the 5.5 K operating temperature is done with helium vapor. Initially the helium flow on orbit will be 10 to 20 times larger than required for steady-state operation. The vent line and the liquid-vapor phase separator (porous plug) therefore must accomodate a large dynamic operational range. For ground testing of IR instruments, the required temperature is 1.5 K. The helium tank temperature for both ground testing and space operations thus needs to be 1.4 K. We will present a discussion of the requirements, a conceptual design, and initial laboratory test results with candidate porous plugs and associated instrumentation. A discussion of possible connections to the design of Gravity Probe-B cryostat will also be presented.

infrared space helium cryostat↗
NASA NTRS1990

High energy astrophysics 21st century workshop 'Space Capabilities in the 21st Century'

An overview of 20th-century NASA accomplishments and of the infrastructure and technology that NASA plans to have in place in the 21st century is presented. Attention is given to the Great Observatories Program, AXAF, the Space Infrared Telescope Facility, the Cosmic Background Explorer, the Small Explorers Program, the Large Area Modular Array of Reflectors, and the X-Ray Background Survey Spectrometer. Also discussed are earth-to-orbit communication links, transportation in the 1990s, the evolution of the space infrastructure, and the Space Station Freedom. Consideration is given to the possibilities of the 21st-century infrastructure, with emphasis on exploration on Mars and the moon. Topics addressed include telecommunications, navigation, information management, and 21st-century space science.

Rhome, Robert C.↗
NASA NTRS1995

Wide Dynamic Range Porous Plug for SIRTF

The most recent approach to the Space Infrared Telescope Facility (SIRTF) uses a new design concept in which the telescope is launched warm and subsequently cooled to operating temperature on orbit. At launch, the cryostat is at 2 K and the telescope is at room temperature. Cooldown of the telescope will be accomplished initially through radiation to space. Final cooldown to the 5.5 K operating temperature is done with helium vapor. Initially, the helium flow on orbit will be 20 to 30 times larger than required for steady-state operation. The vent line and the liquid/vapor phase separator (porous plug) therefore must accommodate a large dynamic operational range.For ground testing of IR instruments, the required temperature is 1.5 K. The helium tank temperature for both ground testing and space operations thus needs to be at 1.4 K. We present a discussion of the requirements, a conceptual design, and initial laboratory test results with candidate porous plugs and associated instrumentation. A discussion of possible connections to the design of the Gravity Probe-B cryostat will be presented also.

SIRTF, Liquid/Vapor Phase, Separator, Porous Plug↗
NASA NTRS1989

The flexure assembly design for the SIRTF one-meter primary mirror

A titanium flexure assembly for the Space Infrared Telescope Facility (SIRTF) 1-m primary mirror has been designed to accommodate: (1) the cryogenic cool-down effect on the optical performance of the mirror, (2) the Shuttle launch-load environment, and (3) the support-baseplate manufacturing tolerances. Numerous iterations involving a multidimensional design space search led to an assembly design that provides the stiffness and strength in the vertical (optical axis) and tangential directions to accommodate launch loads, but is compliant radially to accommodate cryogenic cool down. A 'folded back' titanium flexure system was required because of the differential thermal contraction of the aluminum telescope baseplate support and the fused-silica mirror. This unique and innovative flexure assembly represents a totally passive mechanism for accommodating the design launch loads, cryogenic cool down, and out-of-plane baseplate effects.

Richard, R. M.↗
NASA NTRS1998

Construction and Operation of 1-5 Micron Array Camera (Minne-Cam) for the University of Minnesota Observatories

The 1-5 Micron Imaging Infrared (IR) Camera (MinneCam) for the University of Minnesota (UM) observatories has been constructed. It is presently housed at the Mt. Lemmon Observing Facility (MLOF) in Arizona for its inaugural observing run. MinneCam is testing and comparing various observational approaches, and will produce data sets that can be used to define and test data analysis algorithms. The camera is being used in support of studies to define strategies for using NASA's Space Infrared Telescope Facility (SIRTF) for observations of comets and other targets of opportunity. A long term goal is to modify the instrument to accommodate imaging polarimetry. This instrument is presently putting the University of Minnesota observatories in competition with other major IR observatories and is allowing us to develop state-of-the-art instrumentation for the U of M's proposed 2.4 meter telescope proposed jointly with NOAO and the University of Colorado. The camera has provided important research opportunities for the Minnesota IR group, including other faculty and graduate students in the Department of Astronomy.

Gehrz, Robert D.↗
NASA NTRS1988

Superfluid Helium Tanker (SFHT) study

Replenishment of superfluid helium (SFHe) offers the potential of extending the on-orbit life of observatories, satellite instruments, sensors and laboratories which operate in the 2 K temperature regime. A reference set of resupply customers was identified as representing realistic helium servicing requirements and interfaces for the first 10 years of superfluid helium tanker (SFHT) operations. These included the Space Infrared Telescope Facility (SIRTF), the Advanced X-ray Astrophysics Facility (AXAF), the Particle Astrophysics Magnet Facility (Astromag), and the Microgravity and Materials Processing Sciences Facility (MMPS)/Critical Point Phenomena Facility (CPPF). A mixed-fleet approach to SFHT utilization was considered. The tanker permits servicing from the Shuttle cargo bay, in situ when attached to the OMV and carried to the user spacecraft, and as a depot at the Space Station. A SFHT Dewar ground servicing concept was developed which uses a dedicated ground cooling heat exchanger to convert all the liquid, after initial fill as normal fluid, to superfluid for launch. This concept permits the tanker to be filled to a near full condition, and then cooled without any loss of fluid. The final load condition can be saturated superfluid with any desired ullage volume, or the tank can be totally filed and pressurized. The SFHT Dewar and helium plumbing system design has sufficient component redundancy to meet fail-operational, fail-safe requirements, and is designed structurally to meet a 50 mission life usage requirement. Technology development recommendations were made for the selected SFHT concept, and a Program Plan and cost estimate prepared for a phase C/D program spanning 72 months from initiation through first launch in 1997.

Eberhardt, Ralph N.↗