Master of Arts

thesisWhen an object is introduced to a new culture for the first time, how does it transition from the status of a foreign import to a fully integrated object of that culture? Does it ever truly reach this status, or are its foreign origins a part of its identity that are impossible to overlook? What role could the arts of that culture play in adapting a foreign object into part of the culture? I propose to address these questions in specific regard to early modern Japan (1550-1850) through a black lacquered ōtsuzumi drum decorated with a gold powder motif of intersecting arquebuses and powder horns. While it may seem unlikely that a single piece of lacquerware can comment on the larger issues of cultural accommodation and appropriation, careful analysis reveals the way in which adopted firearms, introduced by Portuguese sailors in 1543, shed light on this issue. While the arquebus's militaristic and economic influence on Japan has been firmly established, this thesis investigates how the Kobe Museum's ōtsuzumi is a manifestation of the change that firearms underwent from European imports of pure military value to Japanese items of not just military, but also artistic worth. It resulted from an intermingling of Japanese-Portuguese trade, aesthetics of the noble military class, and cultural accommodation between Europeans and Japanese that complicates our understandings of influence and appropriation. To analyze this process of appropriation and accommodation, the first section begins with a historical overview of lacquer in Japan, focusing on the Momoyama period, and the introduction of firearms. The second section will go into the aesthetics of lacquerware, including the importance of narrative symbolism and use in the performing arts with a particular emphasis on the aural and visual aesthetics of the drum. Finally, I will discuss this drum in the global contexts of the early modern era, which takes into account the tension between the decline in popularity of firearms as well as the survival of the drum. Pieced together, these various aspects will help to construct a better understanding of this unique piece's place in the Japanese Christian material culture of early modern Japan

Phase Control and Eclipse Avoidance in Near Rectilinear Halo Orbits

The baseline trajectory proposed for the Gateway is a southern Earth-Moon L2 Near Rectilinear Halo Orbit (NRHO). Designed to avoid eclipses, the NRHO exhibits a resonance with the lunar synodic period. The current investigation details the eclipse behavior in the baseline NRHO. Then, phase control is added to the orbit maintenance algorithm to regulate perilune passage time and maintain the eclipse-free characteristics of the Gateway reference orbit. A targeting strategy is designed to periodically target back to the long-horizon virtual reference if the orbit diverges over time in the presence of additional perturbations

Method for the calculation of spacecraft umbra and penumbra shadow terminator points

A method for calculating orbital shadow terminator points is presented. The current method employs the use of an iterative process which is used for an accurate determination of shadow points. This calculation methodology is required since orbital perturbation effects can introduce large errors when a spacecraft orbits a planet in a high altitude and/or highly elliptical orbit. To compensate for the required iteration methodology, all reference frame change definitions and calculations are performed with quaternions. Quaternion algebra significantly reduces the computational time required for the accurate determination of shadow terminator points

Trajectory Design Tools for Libration and Cis-Lunar Environments

Innovative trajectory design tools are required to support challenging multi-body regimes with complex dynamics, uncertain perturbations, and the integration of propulsion influences. Two distinctive tools, Adaptive Trajectory Design and the General Mission Analysis Tool have been developed and certified to provide the astrodynamics community with the ability to design multi-body trajectories. In this paper we discuss the multi-body design process and the capabilities of both tools. Demonstrable applications to confirmed missions, the Lunar IceCube Cubesat lunar mission and the Wide-Field Infrared Survey Telescope (WFIRST) Sun-Earth L2 mission, are presented

Phenomenology of shadow

Experiencing the landscape and skyscape in which for example an astronomically relevant ancient site is located allows for a deep exploration of possible meanings of embedded alignments. In Skyscape Archaeology phenomenology of the landscape is commonly used. Following from this approach and similar to the phenomenology of nature inspired by Goethe, a deep and detailed engagement with a site and standing stones can offer the opportunity to tap into meanings so far overlooked. The following will illustrate how the experience of shadows cast by and on a standing stone at Gardom’s Edge can add to an archaeoastronomical narrative. During the summer solstice the stone seems to lose its shadow or embody it in stone. When looking at anthropological evidence, the shadow can be an essential part of any living being. It becomes clear that a monument with a lost shadow has gained an added dimension of power and liminality; thereby possibly constraining its position within the landscape. Using this example, a more general phenomenology of shadows will be developed that can allow other researchers to find their way into a deeper and richer engagement with a site or monument. Ultimately, it will allow another avenue towards skyscape archaeology

Explicit relations and criteria for eclipses, transits and occultations

Solar system, exoplanet and stellar science rely on transits, eclipses and occultations for dynamical and physical insight. Often, the geometry of these configurations are modelled by assuming a particular viewpoint. Here, instead, I derive user-friendly formulae from first principles independent of viewpoint and in three dimensions. I generalise the results of Veras & Breedt (2017) by (i) characterising three-body systems which are in transit but are not necessarily perfectly aligned, and by (ii) incorporating motion. For a given snapshot in time, I derive explicit criteria to determine whether a system is in or out of transit, if an eclipse is total or annular, and expressions for the size of the shadow, including their extreme values and a condition for engulfment. These results are exact. For orbital motion, I instead obtain approximate results. By assuming fixed orbits, I derive a single implicit algebraic relation which can be solved to obtain the frequency and duration of transit events – including ingresses and egresses – for combinations of moons, planets and stars on arbitrarily inclined circular orbits; the eccentric case requires the solution of Kepler’s equation but remains algebraic. I prove that a transit shadow – whether umbral, antumbral or penumbral – takes the shape of a parabolic cylinder, and finally present geometric constraints on Earth-based observers hoping to detect a three-body syzygy (or perfect alignment) – either in extrasolar systems or within the solar system – potentially as a double annular eclipse

Modification of Caloris ejecta blocks by long-lived mass-wasting: A volatile-driven process?

The Caloris basin is the largest well-preserved impact basin on Mercury. As such, Caloris ejecta afford us an opportunity to study material from Mercury’s deep interior with remote sensing. We have made observations of the geomorphology, colour, distribution, and flank slopes of the circum-Caloris knobs. Our observations suggest that these circum-Caloris knobs are modified ejecta blocks from the Caloris impact. High-resolution MESSENGER images show that knobs are conical and relatively uncratered compared with the surrounding plains, which implies the knobs have undergone resurfacing. We have observed material that has sloughed off knobs superposing impact craters that demonstrably postdate the Caloris impact, which requires some knob modification to have been more recent. We have observed hollows, depressions in Mercury’s surface generally believed to have been caused by volatile-loss, on and closely associated with several knobs, which indicates that many knobs contain volatile material and that knob modification could extend into Mercury’s recent past. Our measurements show that knob flanks typically have slopes of ∼21°, which is steep for a mound of unconsolidated material that was originally emplaced ∼3.8 Ga. The conical shape of knobs, their steep slopes, the dearth of superposed craters on knobs, and knob superposition relationships with other landforms suggest that Caloris ejecta blocks of arbitrary original shape were modified into their present shapes by long-lived mass-wasting. Mass-wasting must have dominated over impact gardening, which would have produced domal morphologies only. We suggest that mass-wasting was probably driven by volatile-loss, in a manner analogous to terrestrial landforms called ‘molards’. If the circum-Caloris knobs are analogous to molards, then they represent a landform and a process hitherto undocumented on Mercury, with implications for the volatile content of the planet’s interior. These knobs therefore are prime targets for BepiColombo, which could search for fresh failures and volatile exposures in the knobs

Fifty Year Canon of Lunar Eclipses: 1986-2035

A complete catalog is presented, listing the general circumstances of every lunar eclipse from 1901 through 2100. To compliment this catalog, a set of figures illustrate the basic Moon-shadow geometry and global visibility for every lunar eclipse over the 200 year interval. Focusing in on the next fifty years, 114 detailed diagrams show the Moon's path through Earth's shadow during every eclipse, including contact times at each phase. The accompanying cylindrical projection maps of Earth show regions of hemispheric visibility for all phases. The appendices discuss eclipse geometry, eclipse frequency and recurrence, enlargement of Earth's shadow, crater timings, eclipse brightness and time determination. Finally, a simple FORTRAN program is provided which can be used to predict the occurrence and general characteristics of lunar eclipses. This work is a companion volume to NASA Reference Publication 1178: Fifty Year Canon of Solar Eclipses: 1986-2035