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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

The Large Space Telescope - A new adventure

A description is presented of the Large Space Telescope (LST), which will be launched in 1982 and can accomodate four scientific instruments at any given time, permitting spectrographic and photometric observations between 1200 A in the UV and 1 mm in the IR. Basic elements of the LST are the optical telescope assembly, the scientific instruments (cameras, spectrographs, photometers, and an astrometer), and the support-systems module. Developmental as well as observational considerations are discussed, including various approaches to testing, maintenance, data transmission and processing, instrument calibration, housekeeping, and refurbishment. A possible mission scenario is outlined.

Friedlaender, F. M.↗

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↗

Research study entitled advanced X-ray astrophysical observatory (AXAF)

General background and overview material are presented along with data from studies performed to determine the sensitivity, feasibility, and required performance of systems for a total X-ray telescope assembly. Topics covered include: optical design, mirror support concepts, mirror weight estimates, the effects of l g on mirror elements, mirror assembly resonant frequencies, optical bench considerations, temperature control of the mirror assembly, and the aspect determination system.

Rasche, R. W.↗

A telescopic jib for continuous adjustment

For special space applications, e.g. for experiments distant from any orbital platforms or manipulators a new kind of jibs with extreme extension capacity has to be designed. Considering the requirements, the telescopic principle is found to be the most promising. For the choice of the stiff structure, design criteria are evaluated. Special effort deals with the drive system. An electromechanical system can satisfy the requirements. First results of the development of such a drive are presented. The most significant features are: A telescopic assembly of tubes which can be mutually moved by a short spindle in the center of the package. An elastically suspended screw is located at the bottom of each tube. For the jib extension, these screws will be linked with the spindle. The control of their sequence and the adjustment of tubes in mutual end positions are performed by latches. A functional model proved the basic idea.

Etzler, C. C.↗

Error budget analysis for advanced X-ray Astrophysics Facility (AXAF)

The AXAF telescope was analytically investigated during the period from September 1979 to March 1980. The results of a performance evaluation in the presence of aligment errors and surface defects, a sensitivity analysis of every individual subsystem, and a diffraction analysis of the telescope assembly are presented.

Korsch, D.↗

Space telescope, a long-life free flyer

The paper describes NASA's Space Telescope (ST) adapted to Shuttle capabilities for launch and retrieval which utilizes the full Shuttle cargo bay space available for payloads and can be returned to the ground for refurbishment. Its objective is to maximize ST's productive lifetime, to probe the universe, and to analyze light from energy sources which cannot be studied by ground-based telescopes. The Shuttle orbiting lifetime will be extended to at least five years, and scientific instruments or failed spacecraft components will be replaced on-orbit. The ST will be returned to earth for major overhauls, refurbished, and relaunched. In summary, the Shuttle will allow space astronomy to be accomplished in the usual manner - by observing, adjusting, changing detectors, and reobserving. The support systems module, the optical telescope assembly, scientific instruments, including the wide field/planetary camera, the faint object spectrograph and the high speed photometer are described.

Field, E. L.↗

A normal incidence, high resolution X-ray telescope for solar coronal observations

A Normal Incidence high resolution X-ray Telescope is reported. The design of a telescope assembly which, after fabrication, will be integrated with the mirror fabrication process is described. The assembly is engineered to fit into the Black Brant rocket skin to survive sounding rocket launch conditions. A flight ready camera is modified and tested.

Golub, L.↗

Space Telescope maintenance and refurbishment

The Space Telescope (ST) represents a new concept regarding spaceborne astronomical observatories. Maintenance crews will be brought to the orbital worksite to make repairs and replace scientific instruments. For major overhauls the telescope can be temporarily returned to earth with the aid of the Shuttle. It will, thus, be possible to conduct astronomical studies with the ST for two decades or more. The five first-generation scientific instruments used with the ST include a wide field/planetary camera, a faint object camera, a faint object spectrograph, a high resolution spectrograph, and a high speed photometer. Attention is given to the optical telescope assembly, the support systems module, aspects of mission and science operations, unscheduled maintenance, contingency orbital maintenance, planned on-orbit maintenance, ground maintenance, ground refurbishment, and ground logistics.

Trucks, H. F.↗

MLRS - A lunar/artificial satellite laser ranging facility at the McDonald Observatory

Experience from lunar and satellite laser ranging experiments carried out at McDonald Observatory has been used to design the McDonald Laser Ranging Station (MLRS). The MLRS is a dual-purpose installation designed to obtain observations from the LAGEOS satellite and lunar targets. The instruments used at the station include a telescope assembly 0.76 meters in diameter; a Q-switched doubled neodymium YAG laser with a pulse rate of three nanoseconds; and a GaAs photodetector with Fabry-Perot interferometric filter. A functional diagram of the system is provided. The operating parameters of the instruments are summarized in a table.

Shelus, P. J.↗

The Advanced X-ray Astrophysics Facility instrument interface requirements

A variety of instruments will be placed at the focus of the Advanced X-ray Astrophysics Facility (AXAF) telescope, either by moving them into focus through the use of an instrument carousel or by moving the telescope assembly. Focal plane instrument categories under consideration for AXAF encompass high and moderate resolution X-ray cameras, X-ray spectrometers, and polarimeters; some of these instruments may require such consumables as a cryogen, in the case of solid state device cooling, or a gas, as in the case of proportional counters. Attention is presently given to interface requirements impacting on the maintenance that must be conducted over the 15-year service life of AXAF, and, especially, on the 'aspect solution' criteria that must be met to minimize stiffness stability criteria.

Weisskopf, M. C.↗

Performance characterization of the Hubble Space Telescope Rate Gyro Assembly

An account is given of the design features and performance characteristics of the Rate Gyro Assembly employed by the Hubble Space Telescope's Pointing Control System to effect accurate spacecraft maneuvers and support fine pointing telescope operation, in conjunction with the fine guidance sensors. The rate sensor attitude quantization is 0.00025 arcsec. Fine-pointing stability is the driver for gyro noise performance, while spacecraft-pointing accuracy requirements at the end of maneuvers has driven the gyro scale factor and mechanical alignment stability performance.

Dougherty, H.↗

Exploring the Universe with the Hubble Space Telescope

A general overview is given of the operations, engineering challenges, and components of the Hubble Space Telescope. Deployment, checkout and servicing in space are discussed. The optical telescope assembly, focal plane scientific instruments, wide field/planetary camera, faint object spectrograph, faint object camera, Goddard high resolution spectrograph, high speed photometer, fine guidance sensors, second generation technology, and support systems and services are reviewed.

Source record↗

Hubble Space Telescope: SRM/QA observations and lessons learned

The Hubble Space Telescope (HST) Optical Systems Board of Investigation was established on July 2, 1990 to review, analyze, and evaluate the facts and circumstances regarding the manufacture, development, and testing of the HST Optical Telescope Assembly (OTA). Specifically, the board was tasked to ascertain what caused the spherical aberration and how it escaped notice until on-orbit operation. The error that caused the on-orbit spherical aberration in the primary mirror was traced to the assembly process of the Reflective Null Corrector, one of the three Null Correctors developed as special test equipment (STE) to measure and test the primary mirror. Therefore, the safety, reliability, maintainability, and quality assurance (SRM&QA) investigation covers the events and the overall product assurance environment during the manufacturing phase of the primary mirror and Null Correctors (from 1978 through 1981). The SRM&QA issues that were identified during the HST investigation are summarized. The crucial product assurance requirements (including nonconformance processing) for the HST are examined. The history of Quality Assurance (QA) practices at Perkin-Elmer (P-E) for the period under investigation are reviewed. The importance of the information management function is discussed relative to data retention/control issues. Metrology and other critical technical issues also are discussed. The SRM&QA lessons learned from the investigation are presented along with specific recommendations. Appendix A provides the MSFC SRM&QA report. Appendix B provides supplemental reference materials. Appendix C presents the findings of the independent optical consultants, Optical Research Associates (ORA). Appendix D provides further details of the fault-tree analysis portion of the investigation process.

Rodney, George A.↗

The application of linear actuators for telescope pointing control

A study team at MSFC has conceptually designed two lunar-based telescopes, a 16 m aperture Large Lunar Telescope (LLT) and a 4 m Cluster Telescope Experiment (CTE). The CTE serves as a technology tested for the LLT. The CTE utilizes a hexapod telescope mount to obtain a small gimbal angle that significantly extends the viewing space and observation time from that of a stationary transit telescope. This paper addresses the applicability of six linear actuators to provide limited gimbal rotation of the CTE telescope assembly. Kinematic constraint equations for the hexapod mount have been applied to a six degree-of-freedom rigid body model. Static equilibrium equations have been solved to address configuration design issues, and a feedback tracking control system has been designed and simulated.

Carrington, C. K.↗

Near-term SEI science missions utilizing an evolutionary lunar transportation system

An evolutionary program of space science missions for the lunar surface and the transportation system concept developed to deploy them are described. Lunar-based science systems will evolve from simple, robotic instruments such as a lunar transit telescope (LTT) to large, observatory-class instruments like a 16-meter optical telescope assembled by astronauts at a lunar base. A transportation system concept to support the Space Exploration Initiative (SEI) and the deployment of these science payloads is described. Beginning with a post-Artemis lander capability, a modular approach to lunar landers is proposed as a way to maximize commonality and to support evolving SEI transportation requirements.

Johnson, Charles L.↗