Design of an Electrically-Propelled Asteroid Rendezvous Probe Launched as a Secondary Payload

This paper summarises a design study undertaken as a final year project for the author’s B.Eng in Aerospace Systems Engineering. A spacecraft design is outlined for a vehicle to perform a rendezvous with a near earth asteroid after being launched as a secondary payload into Geosynchronous Transfer Orbit. The 380 kg (dry) spacecraft would use a bipropellant chemical propulsion system to manoeuvre in, and escape from Earth orbit. Interplanetary maneuvering would be accomplished with an ion propulsion system

Electric Propulsion for Small Spacecraft

Electric Propulsion (EP) is that in which electrical energy, rather than chemical energy, is used to accelerate a propellant to produce thrust. This paper surveys the EP technologies applicable for use on small spacecraft, paying attention to the unique constraints imposed by this application. The very high specific impulse that can be generated by an EP system offers the potential of greatly expanding the scope of missions that can be achieved by small spacecraft. The paper considers the various missions already identified, and outlines a promising small deep space probe using ion propulsion

The Magnificat and Nunc Dimittis of Sir John Tavener: Byzantine Influences on Tavener’s So-Called Holy Minimalism Style of Composition

When British composer Sir John Tavener (1944-2013) converted to the Orthodox faith in 1977, he began to incorporate elements of Byzantine music into his own style. By his own admission, his early attempts were not fully successful, but by the time of his Orthodox Vigil Service (1984) he had a much better handle on Orthodox tones and liturgical practice. While Tavener was familiar with the research on Byzantine chant by Egon Wellesz, he felt that Byzantine chant could only be learned through experience.Some scholars have cited Tavener as an example of the Holy Minimalism style of composition, and in this article I analyze Tavener’s choral pieces Magnificat and Nunc dimittis (1986) to show a specific example of how Byzantine influences on a Western composer helped to create a unique style (although I argue that the Holy Minimalism label is not quite appropriate for Tavener’s music). In these works, Tavener took ideas from a traditional Greek folk song and used Byzantine devices such as the ison and chant melodic patterns, along with incorporating a Byzantine verse in the Magnificat. The Magnificat and Nunc dimittis are proved to be fruitful examples of the importance of Byzantine influences in Tavener’s music

UoGAS - A Get Away Special Satellite with Orbit-Raising Capability

The low cost of satellite deployment from Shuttle GAS canister makes it an attractive launch option. However, the low deployment altitude severely constrains lifetime so the UoGAS (University of Surrey Get Away Special) spacecraft will incorporate a propulsion system. Lifetime extension methods are considered and a start-of-mission orbit-raising manoeuvre is selected. An orbit dynamics simulation method (taking into account the atmospheric drag) is discussed and results presented. Mission profiles, propulsion systems (including colloid, resistojet and cold gas thrusters, as well as a novel hybrid bipropellant combination) and stabilisation options are discussed: an aerodynamically stabilised vehicle with a resistojet propulsion system is suggested and some design aspects of the satellite systems are discussed

The Refined Swampland Distance Conjecture in Calabi-Yau Moduli Spaces

The Swampland Distance Conjecture claims that effective theories derived from a consistent theory of quantum gravity only have a finite range of validity. This will imply drastic consequences for string theory model building. The refined version of this conjecture says that this range is of the order of the naturally built in scale, namely the Planck scale. It is investigated whether the Refined Swampland Distance Conjecture is consistent with proper field distances arising in the well understood moduli spaces of Calabi-Yau compactification. Investigating in particular the non-geometric phases of Kahler moduli spaces of dimension $h^{11}\in\{1,2,101\}$, we always found proper field distances that are smaller than the Planck-length.Comment: 71 pages, 11 figures, v2: refs added, typos correcte

A Multiyear Dust Devil Vortex Survey Using an Automated Search of Pressure Time Series

Dust devils occur in arid climates on the Earth and ubiquitously on Mars, where they likely dominate the supply of atmospheric dust and influence climate. Martian dust devils have been studied with a combination of orbiting and landed spacecraft, while most studies of terrestrial dust devils have involved manned monitoring of field sites, which can be costly both in time and personnel. As an alternative approach, we describe a multiyear in situ survey of terrestrial dust devils using pressure loggers deployed at El Dorado Playa in Nevada, USA, a site known for dust devil activity. Analogous to previous surveys for Martian dust devils, we conduct a posthoc analysis of the barometric data to search for putative dust devil pressure dips using a new automated detection algorithm. We investigate the completeness and false positive rates of our new algorithm and conduct several statistically robust analyses of the resulting population of dips. We also investigate possible seasonal, annual, and spatial variability of the putative dust devil dips, possible correlations with precipitation, and the influence of sample size on the derived population statistics. Our results suggest that large numbers of dips (\u3e1000) collected over multiple seasons are probably required for accurate assessment of the underlying dust devil population. Correlating long-term barometric time series with other data streams (e.g., solar flux measurements from photovoltaic cells) can uniquely elucidate the natures and origins of dust devils, and accurately assessing their influence requires consideration of the full distribution of dust devil properties, rather than average values

The Instrumented Frisbee(Registered TradeMark) as a Prototype for Planetary Entry Probes

A Frisbee has been equipped with sensors, batteries and micro-controllers for data acquisition to record its translational accelerations and attitude motion. The experiments explore the capabilities and limitations of sensors on a rapidly-rotating platform moving in air, and illustrate several of the complex gyrodynamic aspects of frisbee flight. The experiments constitute an instructive exercise in aerospace vehicle systems integration and in attitude reconstruction