A TREETOPS simulation of the Hubble Space Telescope-High Gain Antenna interaction

Virtually any project dealing with the control of a Large Space Structure (LSS) will involve some level of verification by digital computer simulation. While the Hubble Space Telescope might not normally be included in a discussion of LSS, it is presented to highlight a recently developed simulation and analysis program named TREETOPS. TREETOPS provides digital simulation, linearization, and control system interaction of flexible, multibody spacecraft which admit to a point-connected tree topology. The HST application of TREETOPS is intended to familiarize the LSS community with TREETOPS by presenting a user perspective of its key features

Controls, Astrophysics, and Structures Experiment in Space (CASES)

As the size and performance requirements of future NASA and DOD spacecrafts and payloads tend to increase, the associated control systems that must effect these requirements tend to interact with the vehicle's structural dynamics. Some of the Control Structure Interaction (CSI) issues are being addressed in a flight experiment which is entitled CASES (Controls, Astrophysics and Structures Experiment in Space). As one of the first CSI flight experiments, the main emphasis for CASES is to provide a test bed for validating CSI developments and simultaneously, to pave the way for subsequent CSI experiments and science missions by establishing precedents for flight qualifying Large Space Structures (LSS)-class spacecraft. In addition, CASES provides an opportunity to obtain data bases for in-space controls and structures experiments and, at the same time, to gather hard x ray data from pertinent galactic sources

A study of the accepted, referred and rejected applications from October 14, 1946 to February 28, 1947 at the Veterans Administration Mental Hygiene Clinic, Providence, Rhode Island

Thesis (M.S.)--Boston University, 1947. This item was digitized by the Internet Archive

Electrical Actuation Technology Bridging

This document contains the proceedings of the NASA Electrical Actuation Technology Bridging (ELA-TB) Workshop held in Huntsville, Alabama, September 29-October 1, 1992. The workshop was sponsored by the NASA Office of Space Systems Development and Marshall Space Flight Center (MSFC). The workshop addressed key technologies bridging the entire field of electrical actuation including systems methodology, control electronics, power source systems, reliability, maintainability, and vehicle health management with special emphasis on thrust vector control (TVC) applications on NASA launch vehicles. Speakers were drawn primarily from industry with participation from universities and government. In addition, prototype hardware demonstrations were held at the MSFC Propulsion Laboratory each afternoon. Splinter sessions held on the final day afforded the opportunity to discuss key issues and to provide overall recommendations. Presentations are included in this document

Common Proper-Motion Halo Stars

Using the PPMXL proper-motion catalogue we have attempted to compile our own catalogue of common-proper-motion halo candidates, for use in a study of the difference in the lower end of the metallicity distribution of Globular clusters [⁄] = −2.4 and single field stars [⁄] = −4.1. This was achieved by tailoring several selection criteria based on the expected characteristics of typical halo stars, such as similar proper-motions and reduced proper motion data, and applying them to the chosen proper-motion catalogue. The final selection criteria produced a catalogue of 17,500 common proper-motion (CPM) halo binary candidates, and have been further refined to 2,326 pairs based on conclusions drawn from our analysis of the larger catalogue, and have shown that several pre-existing CPM halo binaries are included in the catalogue. A selection of 528 pairs has been identified from this final catalogue as having an increased likelihood over the larger catalogue of being CPM binary pairs. A large number of issues have been identified with the PPMXL catalogue; chiefly among them is the large proportion of data that has been found to be spurious, caused in part by methods used in the creation of the original catalogue, which are discussed in this study. Additional faults found with the final catalogue lead us to the conclusion during the project that the data was of insufficient quality for the planned study on the metallicity distribution; however the refined catalogue and especially the 528 high-interest pairs are likely good candidates for finding real, wide halo binaries. Instead, identification of numerous problems found in the United States Naval Observatory, USNO-B1, catalogue and discussion of their likely causes has been performed. A sample of 600,000 stars were found that share the characteristics of halo giants, though it is demonstrated that a large number of these are likely foreground disk stars

Dopamine receptor subtypes: Influences on local cerebral blood flow and function-related glucose utilisation

In recent years, two pharmacologically distinct subpopulations of dopamine receptor, designated and D2 have been found in brain and vascular tissue. The development of new classes of chemical compounds which discriminate between the subpopulations of dopamine receptor now permits the examination of dopaminergic mechanisms with a precision hitherto impossible. Of these, the benzazepine derivative SKF 38393 possesses a high degree of selectivity for the receptor while the partial ergoline LY 141865 (or as its biologically active enantiomer LY 171555) is a selective D2 agonist. These agents have been used extensively to examine anatomical distribution and neurochemical properties of the and D2 subpopulations in vitro. However, little is known about the effects of pharmacological manipulation of the and D2 receptor subpopulations upon the integrated activity of the brain in vivo

The influence of British business interests on Anglo-Japanese relations, 1933-1937.

The purpose of this study is to examine and explain the impact of British business interests, outside of China, on Anglo-Japanese foreign relations and whether these business pressures contributed to the destablisation or amelioration of political tensions. Between 1933 and 1937 there were a series of major commercial disputes between Britain and Japan, in the cotton and shipping industries and over the Japanese treatment of British oil interests in Japan and Manchukuo, which following Japan's pursuit of an aggressive and unilateral policy in East Asia complicated an already strained Anglo-Japanese relationship. Thus the scale of Anglo-Japanese commercial friction offered substantial scope for political repercussions. In order to assess the impact of business pressure this study will focus upon the relationship between business groups and the British government, which provides the basis for determining the impact of business interests upon British policy towards Japan. By detailing the interaction between government and business this study hopes to establish which factors were most prominent in shaping the government's response to the demands of business and the needs of Anglo-Japanese relations. This requires the examination of the economic and political factors that motivated business demands for government support, and the economic, political and foreign policy factors that guided the response of the British government. However, it also requires the examination of relationships within business groups and the government as a means of establishing the constraints upon business and government's response to Anglo-Japanese commercial friction. Conclusions are drawn which indicate that because of an ingrained 'conservatism' to commercial questions both the business community and government avoided exacerbating commercial tensions with Japan, and consequently business interests had only a limited impact upon Anglo-Japanese relations

An application of the Observer/Kalman Filter Identification (OKID) technique to Hubble flight data

The objective of the current research is to identify vibration parameters, including frequencies, damping ratio and uncertainty characteristics, of the Hubble Space Telescope from flight data using an advanced system identification technique. The Observer/Kalman Filter Identification (OKID) technique is used to identify the vibration parameters. The OKID was recently developed by the researchers in the Spacecraft Dynamics Branch at NASA Langley Research Center

インドの銑鉄輸入にたいする日本の鉄鋼・鋼鉄産業の態度

Despite international attempts to reestablish the prewar free-trade economic system, the 1920s represented a period of flux in economic relations, as countries attempted to sustain economic advantage through more overt business-government cooperation. In this context this paper will look at the political and economic factors involved in the interaction between impacts if the development of the Japanese pig iron industry on Indian imports, and the what was the most effective way of stimulating domestic production without alienating an important overseas supplier, with whom there was a strong interest in maintaining access in that country\u27s domestic market

A demonstration of motion base design alternatives for the National Advanced Driving Simulator

A demonstration of the capability of NASA's Vertical Motion Simulator to simulate two alternative motion base designs for the National Advanced Driving simulator (NADS) is reported. The VMS is located at ARC. The motion base conditions used in this demonstration were as follows: (1) a large translational motion base; and (2) a motion base design with limited translational capability. The latter had translational capability representative of a typical synergistic motion platform. These alternatives were selected to test the prediction that large amplitude translational motion would result in a lower incidence or severity of simulator induced sickness (SIS) than would a limited translational motion base. A total of 10 drivers performed two tasks, slaloms and quick-stops, using each of the motion bases. Physiological, objective, and subjective measures were collected. No reliable differences in SIS between the motion base conditions was found in this demonstration. However, in light of the cost considerations and engineering challenges associated with implementing a large translation motion base, performance of a formal study is recommended