Methods for Combining Payload Parameter Variations with Input Environment

Methods are presented for calculating design limit loads compatible with probabilistic structural design criteria. The approach is based on the concept that the desired limit load, defined as the largest load occuring in a mission, is a random variable having a specific probability distribution which may be determined from extreme-value theory. The design limit load, defined as a particular value of this random limit load, is the value conventionally used in structural design. Methods are presented for determining the limit load probability distributions from both time-domain and frequency-domain dynamic load simulations. Numerical demonstrations of the methods are also presented

Evaluation of a metal fuselage frame selectively reinforced with filamentary composites for space shuttle application

The development of metal structures reinforced with filamentary composites as a weight saving feature of the space shuttle components is discussed. A frame was selected for study that was representative of the type of construction used in the bulk frames of the orbiter vehicle. Theoretical and experimental investigations were conducted. Component tests were performed to evaluate the critical details used in the designs and to provide credibility to the weight saving results. A model frame was constructed of the reinforced metal material to provide a final evaluation of the construction under realistic load conditions

Effect of damping on excitability of high-order normal modes

The effect of localized structural damping on the excitability of higher-order large space telescope spacecraft modes is investigated. A preprocessor computer program is developed to incorporate Voigt structural joint damping models in a finite-element dynamic model. A postprocessor computer program is developed to select critical modes for low-frequency attitude control problems and for higher-frequency fine-stabilization problems. The selection is accomplished by ranking the flexible modes based on coefficients for rate gyro, position gyro, and optical sensor, and on image-plane motions due to sinusoidal or random PSD force and torque inputs

Simplified thermal estimation techniques for large space structures

A tool for making rapid estimates of the response of space structures to thermal environments encountered in earth orbits is provided for the designer of these structures. Charts giving heating rates and temperatures for certain typical large spacecraft structural elements are provided. Background information for spacecraft thermal design considerations is presented. Environments, requirements, thermal control techniques, design guidelines, and approaches available for more detailed thermal response analysis are discussed

Lightweight Vacuum Jacket for Cryogenic Insulation - Appendices to Final Report

The feasibility is demonstrated of producing a lightweight vacuum jacket using state-of-the-art technology and materials. Design and analytical studies were made on an orbital maneuvering system fuel tank. Preliminary design details were completed for the tank assembly which included an optimized vacuum jacket and multilayered insulation system. A half-scale LH2 test model was designed and fabricated and a force/stiffness proof test was conducted on the vacuum jacket. A vacuum leak rate of 0.00001 was measured, approximately 1500 hours of vacuum pressure was sustained, and 29 vacuum pressure cycles were experienced prior to failure. For vol. 1, see N75-26192

Girl meets girl: sexual sitings in lesbian romantic comedies

Hollywood romantic comedies are, by and large, an ideologically conservative genre. Based around gender stereotypes and the idealised pursuit, however disguised, of heteropatriarchal monogamy, Hollywood romantic comedies offer countless variations of heteronormative ‘intimacy’. How, then, does the shift from ‘boy meets girl’ to ‘girl meets girl’ in lesbian romantic comedies—a genre that emerged in 1994 with the release of films like Bar Girls and Go Fish—effect the representation of intimacy? This chapter focuses on Better than Chocolate to investigate how lesbian intimacies, and lesbian sex in particular, occupy space. Where are lesbian intimacies sited and what, if any, negotiations of space are triggered through the embodiment of those intimacies? Ultimately, this chapter argues that through an unusually explicit emphasis on sex, Better than Chocolate draws attention to the limited public mobility of lesbian intimacies through a consistent siting of lesbian sex as a site of spatial negotiation

A microfluidic system for the measurement of chemical concentration and density

Abstract A new microfluidic system for measuring chemical concentration, fluid density and specific gravity has been developed. Measurements can be made with under a microliter of sample fluid, which is over 1000 to 3000X less than that required in conventional systems. Since the product is MEMSbased the overall system size is a fraction of conventional fluidic density meters and it weighs much less (1kg vs. 20kg) than traditional desk-top, temperature controlled, density meters. The syringe or pipette loaded system includes a dynamic temperature control system employing thermoelectric panels that operates between 0ºC and 90ºC with a temperature accuracy of less than 0.01ºC and better than 4-digit fluidic density resolution. In order to obtain this temperature and hence density accuracy an on-chip temperature sensor was added to the MEMS chip. Also a new method of chip-level gettering was developed to achieve the sub-milliTorr pressures needed for adequate resonator signal quality