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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

SIRTF - The Shuttle Infrared Telescope Facility

The Shuttle Infrared Telescope (SIRTF) is a 1-m class cryogenically cooled telescope to be operated from the shuttle as a facility for infrared astronomy. By exploiting the very low infrared background of space, SIRTF will achieve 100 to 1000 times the sensitivity currently attainable at infrared wavelengths between 2 and 200 microns. The scientific requirements of SIRTF, the current design concept, and the scientific capabilities of the systems are reviewed. We also review recent experimental results showing that mirrors made of glassy materials may be suitable for use in large cryogenic telescopes such as SIRTF.

Werner, M. W.↗
NASA NTRS1982

Science operations with Space Telescope

The operation, instrumentation, and expected contributions of the Space Telescope are discussed. Space Telescope capabilities are described. The organization and nature of the Space Telescope Science Institute are outlined, including the allocation of observing time and the data rights and data access policies of the institute.

Giacconi, R.↗
NASA NTRS1981

Double Compton scatter telescope calibration

Calibration techniques for a medium energy gamma ray telescope are described. Gain calibration using Compton edge spectra involves comparisons of pulse height spectra with spectra simulated by a Monte Carlo computer code which includes Compton scattering and pair production, plural scattering and variable energy resolution, and cell size. The telescope considered comprises 56 cells of liquid scintillator in four size groups, with a total liquid volume of 325 l; each cell has its own photomultiplier tube. Energy and angular resolutions and the PMT gain calibration procedure are verified with double scatter data for monoenergetic gamma rays at a known location. Detection probabilities for any cell combination in the two telescope arrays are calculated per steradian as a function of the scattering for a number of different energies with a Van de Graaff accelerator.

Dayton, B.↗
NASA NTRS1981

A hard X ray and soft gamma ray telescope spectrometer

A telescope spectrometer in the hard X-ray and soft gamma-ray region from 30 keV to 200 keV can provide significant information in investigations related to solar physics and planetary science. The present study is concerned with the preliminary design of such an instrument, taking into account a use of the Low Intensity X-ray Imaging Scope (Lixiscope). In the design of the considered telescope spectrometer, attention would have to be given to three major components, including the X-ray and gamma-ray input optics, an imaging detector-spectrometer, and an output processor. The preliminary results provided by the present study indicate that, in principle, a complete hard X-ray and soft gamma-ray telescope imaging spectrometer system using the Lixiscope is feasible. However, much work remains to be done with respect to the optimization and improvement of the system for future flight applications.

Yin, L. I.↗
NASA NTRS1982

An image drift compensation system for a solar pointed space telescope

Two sounding rocket test flights have been conducted in the development of an image drift compensation system designed for a solar-pointed space telescope. The system, whose scientific results are presented, employs limb-sensing photodiodes at the telescope focal plane and provides drift compensation to better than + or - 0.1 arcsec. A variation of this device will be employed by the Space Shuttle/Spacelab 2 flight of the High Resolution Telescope and Spectrograph (HRTS) Instrument. The data gathered by the rocket flights of the drift compensation system have revealed high velocity ejecta traveling through the transition zone and corona at velocities up to 400 km/sec. The HRTS configuration and its constitutive instruments' optical parameters are described.

Bartoe, J.-D. F.↗
NASA NTRS1982

Space Telescope design status and operations

The Space Telescope design concept is described in the context of the basic mission objectives. The orbiting telescope is designed to have 10 times better resolution, to see 50 times fainter stars and to have a much broader spectral range than the best existing ground observatories. The project is on schedule for launch in early 1985. Hardware assembly and test has started on the optical system, and the primary and secondary mirrors have been polished and coated. The five scientific instruments are beginning hardware assembly. The last major design review for the spacecraft has been completed, and good progress has been accomplished with the implementation of the pointing control system. The mission operations ground system has been defined and is under development. Control center design is complete and the science institute is under construction. The Space Telescope is designed to be serviceable in orbit and will be capable of return to the ground for refurbishment.

Speer, F. A.↗
NASA NTRS1982

Development of the Ultraviolet Imaging Telescope for the OSS-3 experiment complement

The areas of scientific interest addressed by the Ultraviolet Imaging Telescope (UIT) as part of the OSS-3 (Office of Space Science) experiment complement and the use of the Space Shuttle to make possible extended observations impose constraints in the optical, mechanical, and thermal design areas which are significantly more difficult than those encountered with sounding rocket payloads. Yet, in order that the UIT be cost-effective, it has been designed using the technology proven in the prior sounding rocket flights as a basis. The UIT had its beginnings in a series of eleven Goddard Space Flight Center sounding rocket payloads dating from 1973. Optically and mechanically it is derived from the 13-inch telescope of Rocket 26.008. Its detector design is related to that of Rocket 25.017, launched in 1977. Rocket 27.062, to be launched in 1982, will be the second flight of the 15-inch telescope serving as the direct prototype of the UIT. This evolution of the UIT from the rocket payload configuration, the nature of the new design requirements, and the manner in which the requirements were met are discussed.

Oliver, J. A.↗
NASA NTRS1983

Space telescope: Solar array primary deployment mechanism

The requirements, the design, and the test program which were carried out in producing the Space Telescope Solar Array (STSA) primary deployment mechanisms (PDM) are described. The PDM will be used to rotate the rolled solar array supporting boom from its launch position alongside the telescope housing, through 90 deg to its use position. After five years in space the array is to be rerolled and by use of the PDM swung back to its stowed position alongside the telescope housing for capture and return to Earth via the Space Shuttle.

Chandler, D. P.↗
NASA NTRS1982

Spectroscopic equipment for the Space Telescope

The Space Telescope will provide views of the Universe of remarkable clarity. Central to its capabilities is an f/24 Ritchey-Chretien telescope with 40,000 sq cm unobscured collecting area, which will provide point-source images less than 0.1 sec in radius at wavelengths below 633 nm. It will operate over the range 110 nm to 1 mm. The initial flight instrumentation includes two spectrographs, the Faint Object Spectrograph (F.O.S.) and the High-Resolution Spectrograph (H.R.S.). The F.O.S. is sensitive from 115 to 800 nm. It will provide data at resolving powers 1000-100 on extremely faint sources. The H.R.S. operates at the wavelengths 107-320 nm. It will achieve high photometric accuracy at resolving powers 100,000, in the echelle mode, or 10,000-1000 in first order, on brighter targets. The two cameras on board the Space Telescope will provide ancillary spectroscopic capabilities.

Leckrone, D. S.↗
NASA NTRS1981

Multiple telescope infrared interferometry

The advantages of multiple telescope infrared interferometry are discussed in detail, using the 10 micron region as a specific example. Scale and seeing considerations are addressed, taking into account analytically the distorting effect of turbulent air and discussing the effect of water vapor on seeing. The usefulness of fringe phase determination to determine the intensities in the radiation field, and the effect of atmospheric fluctuations on their use, are considered. Astrometry by means of interferometry is extensively covered, with examples such as a plot of the fringe phase of o Ceti as a function of time compared with a theoretical fringe phase of the star with a fixed best-fit baseline. The sensitivity of an interferometer involving two receiving telescopes is considered. Finally, an example of a telescope design for 10-micron interferometry is described and depicted.

Townes, C. H.↗
NASA NTRS1982

Development of a 1m-normal-incidence-EUV-Telescope

A brief description is given of the 1m-EUV-Telescope and its focal plane instrumentation, namely an EUV spectrometer and six EUV/FUV photometers. The telescope is scheduled for launch on an Aries rocket on June 17, 1982. The principal goals are the white dwarf HZ43 and a photometric scan across the sky in an area of the sky where 21 cm line observations reveal a steep density gradient. The optical bench of the telescope is a cylinder made of a graphite epoxy compound. Despite its low specific weight, the bench shows an excellent mechanical performance, with an elasticity modulus of approximately 70,000 N/cu mm. It is pointed out that by carefully combining layers with different winding angles of the carbon fiber, the thermal expansion along the cylinder axis is almost negligible, even under severe thermal loads

Grewing, M.↗
NASA NTRS1982

Multiple object fiber optics spectrograph feed for the Hale telescope

The preliminary design for a computer-controlled fiber-optics feed linking the 5-m Hale telescope at Palomar Observatory to the entrance slit of an astronomical spectrograph is presented. A 76-mm square field will be divided into ten strips containing two movable fibers each; the fibers can be moved by stepper-motor-driven lead screws to any position on the strip. The device is designed to allow the simultaneous spectrographic observation of many astronomical objects in a small angular field. A prototype feed using two fibers and manually commanded digital control is described in detail. Test observations of two bright O stars made in April, 1981 using the prototype with the Hale telescope are considered sufficiently positive to warrant construction of the 20-fiber feed, which would enhance the spectrographic-survey effectiveness of the telescope by a factor of ten.

Tubbs, E. F.↗
NASA NTRS1983

Space Telescope pointing control

The Space Telescope Pointing Control System is used to slew the optical axis of the telescope from one target star region of the celestial sphere to the next, and to maintain precision pointing on the target star. A digital computer is employed in the processing of attitude and rate sensor data, in order to generate torque commands for the reaction wheels. The System comprises four major elements: a command generator, the electronic control system, attitude update processing, and momentum management. Emphasis is given to control-related flexibility effects of the Space Telescope's solar cell array and vehicle, and the acquisition methodology and development testing employed, in addition to Pointing Control System design features.

Dougherty, H.↗
NASA NTRS1983

A large aperture balloon-borne telescope for a submillimeter wavelength survey of the galactic plane

A balloon-borne, 1.2 meter Cassegrain telescope with a servo-controlled chopping secondary mirror has been developed and used to survey the Galactic Plane at submillimeter wavelengths. The telescope pointing system uses a gyroscope as the primary stabilization reference and makes use of microprocessors for pointing control, on-board data collection, and telemetry formatting. A description of the telescope, multi-channel liquid-helium-cooled focal plane and the aspect and orientation subsystems are presented.

Silverberg, R. F.↗
NASA NTRS1982

SIRTF - The Shuttle Infrared Telescope Facility

The Shuttle Infrared Telescope (SIRTF) is a 1-m class cryogenically cooled telescope to be operated from the Shuttle as a facility for infrared astronomy. By exploiting the very low infrared background of space, SIRTF will achieve 100 to 1000 times the sensitivity currently attainable at infrared wavelengths between 2 and 200 microns. The scientific requirements of SIRTF, the current design concept, and the scientific capabilities of the systems are reviewed. Recent experimental results are also reviewed showing that mirrors made of glassy materials may be suitable for use in large cryogenic telescopes such as SIRTF. Previously announced in STAR as N82-32207

Werner, M. W.↗
NASA NTRS1984

Support structures for large infrared telescopes

An infrared telescope requires an accuracy of its reflecting surfaces of less than a micrometer. Future missions may require such accuracy from telescopes that are 20 meters or larger in diameter. The structure for supporting such a telescope will most probably take the form of a deep truss. Various approaches for constructing the primary mirror in space are illustrated. One that employs automated deployment of interconnected reflector-structure modules was described in detail. Estimates were made of the precision obtainable with properly configured truss structures and the required ability of active control systems for achieving the desired accuracy.

Hedgepeth, J. M.↗
NASA NTRS1984

Theoretical design and analysis of the layered synthetic microstructure optic for the dual path X-ray telescope

A ray tracing analysis was performed for several configurations for the inner channel of the dual path X-ray telescope, which is proposed to use the second mirror of the Stanford/MSFC Wolter-Schwarzchild telescope and a normal incident layered synthetic microstructure (LSM) mirror to form a secondary image near the front of the telescope. The LSM mirror shapes considered were spherical, ellipsoid, hyperboloid, and constant optical path length (OPL) aspheric. Only the constant OPL case gave good axial resolution. All cases had poor off axis resolution as judged by the RMS blur circle radius.

Shealy, D. L.↗
NASA NTRS1984

The solar optical telescope

This paper describes NASA's Solar Optical Telescope (SOT), which is designed to measure the density temperature, magnetic fields, and the nonthermal velocity fields of solar features on a scale at which the basic physical processes are occurring. A series of 7- to 14-day missions carrying a 1.3-meter solar-observing telescope that has a spatial resolution only slightly larger than the photon mean-free-path of about 80 km will be flown as a Spacelab-attached payload aboard the Space Transportation System (STS) in mid-1990. The telescope (Fig. 1) will be built and integrated by the Perkin-Elmer Corporation and is managed by NASA's Goddard Space Flight Center. Coarse pointing to the sun is provided by the Spacelab instrument pointing system (IPS), whereas fine pointing is provided by the Observatory pointing and control system. The science instruments for the first mission, the photometric filtergraph and the coordinated filtergraph/spectrograph, that are integrated into a combined instrument package are also described.

Hogan, G. D.↗