Star tracker axis-to-sunlit earth horizon angle constraint evaluations for rendezvous operations

The results are presented of a study initiated to evaluate the star tracker axis-to-sunlit earth horizon angle constraint with respect to limitations imposed on the passive target rendezvous capability. The data presented include considerations for dispersions and sensor pointing capabilities and generalizations with respect to the uncertainties associated with the angle constraint available in practice

Modelling & Improving Flow Establishment in RSVP

RSVP has developed as a key component for the evolving Internet, and in particular for the Integrated Services Architecture. Therefore, RSVP performance is crucially important; yet this has been little studied up till now. In this paper, we target one of the most important aspects of RSVP: its ability to establish flows. We first identify the factors influencing the performance of the protocol by modelling the establishment mechanism. Then, we propose a Fast Establishment Mechanism (FEM) aimed at speeding up the set-up procedure in RSVP. We analyse FEM by means of simulation, and show that it offers improvements to the performance of RSVP over a range of likely circumstances

Rendezvous radar requirements analysis for mission 3B

Data are presented verifying the compatibility of currently proposed rendezvous radar measurement accuracies with Mission 3B rendezvous requirements. In addition, data presented indicate a potential for increasing the acceptable time lag between termination of thrusting and availability of accurate measurement data. Additional investigation is recommended to define any acceptable time lag above the current proposed value. Finally, Mission 3B rendezvous performance is shown to be sensitive to variations in the relative downrange position dispersions at insertion. It is therefore recommended that insertion relative state dispersions used in studies of 3B rendezvous be reviewed when results of 3B ascent dispersion studies are available

REDO RSVP: Efficient Signalling for Multimedia in the Internet

Alarming reports of performance and scalability problems associated with per-flow reservations, have led many to lose belief in RSVP and the Integrated Services Architecture that relies on it. Because we are convinced of the need for some form of resource reservation, to support multimedia communications in the Internet, we have set about trying to improve RSVP. By careful study of the protocol, we have identified areas for improvement, and propose REDO RSVP, a reduced overhead version that includes a fast establishment mechanism (FEM). In this paper we describe the rationale for REDO RSVP and present a detailed analysis of its features and operations. We also analyse REDO RSVP by means of simulations, and show that it offers improvements to the performance of RSVP

Structural Studies With the Electron Microscope

The use of the electron microscope in the study of ionic processes in solution has not been previously reported. In the present work, the hydrolysis products of zirconyl chloride was examined by high resolution electron microscopy. Characterization of various hydrates of zirconyl chloride was carried out, using X-ray and electron diffraction. The hydrolysis was brought about by the reflux of aqueous solutions of zirconyl chloride. Removal of samples of the colloid at various stages of hydrolysis, and subsequent examination of the solids obtained by rapid dehydration of the samples, using an atomiser, has enabled structural units consistent in size with a proposed tetra-meric cation [Zr(OH)24H2O]8+4 to be resolved in the electron microscope. Single-crystal filaments of chrysotile asbestos were used as a supporting network for the particles, and their lattice images used as a magnification calibration. Later stages of the hydrolysis produced polymerization of these tetra-meric species, and ageing finally produced monoclinic zirconia. The structure and properties of the crystalline zirconia particles is discussed, and evidence from other physical techniques is presented. A suggested mechanism relating the various structures is supported by pH measurements obtained during the hydrolysis, A preliminary study of the hydrolysis of thorium (IV) showed a chain structure in the early stages of the reaction, the chains being similar in diameter to the [Th(CH)2]2n+n chains present in basic thorium salts. A high-resolution electron microscore study of Chrysotile was carried out and the characteristics of fibres from various sources is discussed

Revisiting Employment Division v. Smith

The Supreme Court wrongly decided Employment Division v. Smith. Without briefing or argument over the Free Exercise Clause’s meaning, Smith eliminated the constitutional right to exercise religion and replaced it with an equal protection rule. The decision threatens religious freedom and encourages conflict. The Supreme Court should revisit Smith. This article shows that the majority’s arguments in Smith fail and contradict the Free Exercise Clause’s text, purpose, and original meaning. The Smith majority gave no sound legal or policy reason for its decision. Indeed, the decision conflicted with settled precedents that no party questioned. Nor did it determine the constitutional text’s meaning or examine historical evidence. The decision solely rests on the majority’s mistaken fears that religious liberty would require arbitrary judicial balancing and cause anarchy. The Free Exercise Clause’s text, purpose, and original meaning confirm that the clause protects religious freedom, not equality. The text guarantees the right to exercise religion without government interference—and it presents no exception. History shows why. The founding generation considered religious liberty an unalienable right that supersedes civil duties. This understanding prompted the Founders to protect religious freedom. To this end, the founders used a familiar legal concept from the colonies and states: the free exercise principle. It protected the broad right to freely exercise religion but excluded practices that would endanger peace and safety. The Founders enshrined this principle in the Free Exercise Clause