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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Large Space Telescope Program status

This paper provides an overview of the current status of the LST Program. The history of the program is treated briefly, with emphasis placed on the recent Phase B definition activity. The background and rationale leading to the decision of the aperture size of the LST primary mirror are discussed. The current technical definition status of the LST Optical Telescope Assembly and Support Systems Module is treated in a summary fashion. Key milestone events during the balance of the Phase B definition effort and schedule and over-all planning for the development phase of the program are described.

Downey, J. A., III↗
NASA NTRS1975

Analysis and experimental measurement of straylight suppression systems for the large space telescope

A computer program for straylight suppression system design and analysis was developed to analyze various proposed LST straylight suppression systems. Simultaneously, experimental measurements are being made on a simplified LST straylight suppression system in a unique facility. The experimental measurements are being used to verify and improve the computer program. The facility represents the state-of-the-art in straylight suppression measurements, and transmission factors of 10 to the minus 12th power have been measured.

Wyman, C. L.↗
NASA NTRS1977

A scientific operations plan for the large space telescope

The paper describes an LST ground system which is compatible with the operational requirements of the LST. The goal of the approach is to minimize the cost of post launch operations without seriously compromising the quality and total throughput of LST science. Attention is given to cost constraints and guidelines, the telemetry operations processing systems (TELOPS), the image processing facility, ground system planning and data flow, and scientific interfaces.

West, D. K.↗
NASA NTRS1980

Study of stray light suppression for the large space telescope

Analysis of light scattering, using the APART computer program, begins at the image plane and progresses through the optical system to the front end of the telescope tube. The approach identifies all critical surfaces, computes the geometrical configuration factors (GCF) from each area of the system under study to all other areas of the system, and determines incident and reflected angles which are important for baffle surfaces which do not have Lambertian scattering characteristics. The power input into the optical surface from either point source objects or extended objects such as the bright Earth are computed. The surface scattering characteristics and the GCF values are combined so that the power transfer to the image plane is computed. Capabilities for handling light scattering from baffle surfaces, specular reflectance from black surfaces, scattering from mirror surfaces, diffraction, internal scattering from transmissive optics, and internal thermal emission are assessed.

Fannin, B. B.↗
NASA NTRS1980

A very large space telescope for optical/UV astronomy

A concept is presented for a Ritchey-Chretien optical-UV telescope to be deployed in orbit using a preassembled segmented primary mirror of 8 meter aperture, carried into orbit inside the modified interstage of the Space Shuttle External Tank. Shuttle revisits allow major assembly tasks to proceed such as the installation of the light shield, fine alignment of the system and attachment of scientific instrument modules to the instrument adapter. Prime technology requirements for the VLST are assessed in this paper.

Nein, M. E.↗
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 NTRS1985

An optical technology study on large aperture telescopes

The difficult and crucial problem of selecting a suitable telescope concept for an advanced space observatory was examined. To this end two and four mirror telescopes were analyzed and compared. Both configurations are very practical and structurally similar. Parabolic primary and spherical primary four mirror telescope were compared with respect to their performance and the alignment sensitivities of the three correction mirrors. A 1 meter class afocal telescope system with lag angle compensation, to be used in a LIDAR experiment, was examined.

Korsch, D.↗
NASA NTRS1990

Construction of the 16 meter Large Lunar Telescope (LLT)

The different materials that could be used to design the pedestal for a Moon based 16 meter telescope are discussed. The material that should be used has a low coefficient of thermal expansion, high modulus of elasticity, and high compressive and tensile strengths. For the model developed in this study, an aluminum-manganese alloy was used because of its low coefficient of thermal expansion. Due to variations in lunar soil conditions, both vertically and horizontally, three foundation systems are presented. The spudcan footing can be used in the case where dense soil is more than three meters. The spread footing is recommended where the dense soil is between one and three meters. Finally, in the third system, the Lunar Excursion Vehicle (LEV) is used as a base support for the telescope's pedestal. The LEV support requires a prepared site. The soil should be compacted and stabilized, if necessary, to reduce settlement.

Omar, Husam Anwar↗
NASA NTRS2002

Status of NASA Mirror Technology Development for Large Space Telescopes

This paper presents the current status of several NASA technology development activities, including: Sub-scale Beryllium Mirror Demonstrator (SBMD), NGST (Next Generation Space Telescope) Mirror System Demonstrator (NMSD), Advanced Mirror System Demonstrator (AMSD), etc.. It also describes how these activities map into future NASA mission requirements, including: Next Generation Space Telescope (NGST), Single Aperture Far Infrared Observatory (SAFIR), Space Ultraviolet/Optical Observatory (SUVO), etc..

Stahl, H. Philip↗
NASA NTRS2002

Status of NASA Mirror Technology Development for Large Space Telescopes

This talk will present the current status of several NASA technology development activities, including: SBMD, NMSD, AMSD (Advanced Mirror System Demonstrator), etc.. And will discuss how these activities map into future NASA mission requirements, including: NGST (Next Generation Space Telescope), SAFIR, SUVO, etc.

Stahl, H. Philip↗
NASA NTRS2009

Formation Flying of Components of a Large Space Telescope

A conceptual space telescope having an aperture tens of meters wide and a focal length of hundreds of meters would be implemented as a group of six separate optical modules flying in formation: a primary-membrane-mirror module, a relay-mirror module, a focal-plane-assembly module containing a fast steering mirror and secondary and tertiary optics, a primary-mirror-figure-sensing module, a scanning-electron-beam module for controlling the shape of the primary mirror, and a sunshade module. Formation flying would make it unnecessary to maintain the required precise alignments among the modules by means of an impractically massive rigid structure. Instead, a control system operating in conjunction with a metrology system comprising optical and radio subsystems would control the firing of small thrusters on the separate modules to maintain the formation, thereby acting as a virtual rigid structure. The control system would utilize a combination of centralized- and decentralized-control methods according to a leader-follower approach. The feasibility of the concept was demonstrated in computational simulations that showed that relative positions could be maintained to within a fraction of a millimeter and orientations to within several microradians.

Mettler, Edward↗
NASA NTRS2010

Recent Results on SNRs and PWNe from the Fermi Large Area Telescope

a) Symbiotic Binary System: White dwarf + red giant system. b) Nova: White dwarf builds up mass envelope to the point of thermonuclear fusion. c) Dramatic increase in visual magnitude. d) Recurrent Nova? e) Hints but no strong confirmation of previous nova f) Pre-nova activity: 1) White dwarf shows ongoing variability at level of several in magnitude. 2) V407 Cyg companion is a Mira star showing variability at level of several in magnitude. g) Origin of the gamma rays? 1) Strong shock propagating into dense medium around giant star land stellar wind. 2) Pion decay or electron processes?

Hays, Elizabeth↗
NASA NTRS2011

Future Multiwavelength Studies with the Fermi Large Area Telescope

With two and a half years of experience, Fermi LAT contributions to multiwavelength studies have become an integral part of many astrophysical research projects. Future efforts will benefit from (1) Deeper LAT exposures} resulting in more sources; (2) More high-energy, high-angular resolution photons, giving better source locations and imaging; (3) Faster analysis of variability and announcements to the community; and (4) Longer time series for studies of variable source properties in comparison to other wavelengths.

Thompson, David J.↗
NASA NTRS2014

Advanced Mirror Technology Development (AMTD) for Very Large Space Telescopes

Advanced Mirror Technology Development (AMTD) is a multi-year effort to systematically mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. This technology must enable missions capable of both general astrophysics & ultra-high contrast observations of exoplanets. To accomplish our objective, We use a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system.

Stahl, H. Philip↗