Gender and Videogames: The political valency of Lara Croft

The Face: Is Lara a feminist icon or a sexist fantasy? Toby Gard: Neither and a bit of both. Lara was designed to be a tough, self-reliant, intelligent woman. She confounds all the sexist cliches apart from the fact that she’s got an unbelievable figure. Strong, independent women are the perfect fantasy girls—the untouchable is always the most desirable (Interview with Lara’s creator Toby Gard in The Face magazine, June 1997)

Probing ultrafast dynamics in a solid-density plasma created by an intense femtosecond laser

We report a study on the dynamics of a near-solid density plasma using an ultraviolet (266 nm) femtosecond probe laser pulse, which can penetrate to densities of ∼ 1022 cm-3, nearly an order of magnitude higher than the critical density of the 800 nm, femtosecond pump laser. Time-resolved probe-reflectivity from the plasma shows a rapid decay (picosecond- timescale) while the time-resolved reflected probe spectra show red shifts at early temporal delays and blue shifts at longer delays. This spectral behaviour of the reflected probe can be explained by a laser-driven shock moving inward and a subsequent hydrodynamic free expansion in the outward direction

Manufacturing of a high-temperature resistojet heat exchanger by selective laser melting

The paper presents the design, manufacturing and postproduction analysis of a novel high-temperature spacecraft resistojet heat exchanger manufactured through selective laser melting to validate the manufacturing approach. The work includes the analysis of critical features of a heat exchanger with integrated converging-diverging nozzle as a single piece element. The metrology of the component is investigated using optical analysis and profilometry to verify the integrity of components. A novel process of high-resolution micro-Computed Tomography (CT) is applied as a tool for volumetric non-destructive inspection and conformity since the complex geometry of the thruster does not allow internal examination. The CT volume data is utilised to determine a surface mesh on which a novel perform coordinate measurement technique is applied for nominal/actual comparison and wall thickness analysis. A thin-wall concentric tubular heat exchanger design is determined to meet dimensional accuracy requirements through nominal/actual comparison analysis. The work indicates the production of fine structures with feature sizes below 200 μm in 316L stainless via selective laser melting is feasible and opens up new possibilities for the future developments in multiple industries

Performance testing and evaluation of a high temperature xenon resistojet prototype manufactured by selective laser melting

This paper presents performance testing and evaluation of the AMR-X-0, the first additively manufactured breadboard model resistojet thruster with a novel design of heat exchanger. Testing is performed within the David Fearn Electric Propulsion Laboratory at the University of Southampton. The thruster is characterized at constant flow rates with argon, in both cold gas mode and at a range of electrical power inputs with current regulation. Thrust measurements demonstrate an improvement in ISP of 50% and thus validating the concept and providing insight into the thermal inertia of the AMR-X thruster. The presence of a gas leak caused by a ceramic component is discussed

High performance resistojet thruster: STAR Status Update

This paper presents the performance testing of the Super-high Temperature Additive Resistojet (STAR) prototype, the first additively manufactured resistojet thruster with a novel monolithic design of heat exchanger. In this paper, operation of the concept was demonstrated at the operational temperature limits of the prototype material. In hot gas mode, the prototype developed 80s specific impulse with argon gas, with a calculated stagnation temperature between 380°C and 500°C at the inlet of the nozzle. The paper proves the feasibility of operation of a concentric thin walled monolithic recirculating resistojet manufactured via selective laser melting

The Development of a Family of Resistojet Thruster Propulsion Systems for Small Spacecraft

The advance in complexity and sophistication of small satellite missions is increasingly requiring that these spacecraft have on-board propulsion systems. However, there is a different emphasis on these small systems as opposed to the traditional propulsion systems on larger spacecraft. The systems must be low cost, low volume and safe. Traditionally cold gas nitrogen systems have been used as they provide a simple solution, combining high reliability with low cost and heritage. However cold gas systems tend to be limited by fairly low specific impulses and poor storage densities. One method of enhancing their performance, hence extending the mission life, is by heating the propellant to achieve a higher exhaust velocity. When this is done electrically with resistance heaters it is known as a resistojet. One feature of small satellites is that they are often power limited. Hence a balance must be struck between the propulsion system power requirements and the rest of the spacecraft. This paper will describe some of the features and limitations of using resistojets on small spacecraft and the evolution of the Surrey family of thrusters

An Investigation into Injector Architecture for Sub-Newton Monopropellant Propulsion

This paper presents an exploration of injector architecture candidates, including orifice and Poiseuilletype injectors, for sub-newton monopropellant thrusters. While the work here is specific to High Test Peroxide, it is expected to be applicable to other monopropellants. This methodology presented here seeks to underpin the fluid mechanics through flow characterisation and hot firing of each injector, with analytical, experimental and computational methods. Experimental results broadly follow calculations and simulations, although do not fully agree. Further work is required to fully understand the microscale fluid dynamics, especially as chugging may not be as significant for sub-newton scale monopropellant thrusters

A thermo-fluidic model for a low power xenon resistojet

A next generation high performance xenon resistojet delivering specific impulse above 90s would be of significant benefit to both small and newer all-electric spacecraft. Such performance would require a xenon propellant temperature of > 3000 K for gas dynamic expansion. Operation at such extreme temperatures and power densities requires a detailed understanding of numerous physical processes in order to converge on a workable design. The highly interdependent nature of these processes, such as resistive dissipation, heat transfer, fluid dynamics and material stress, means that studying each of them discreetly only provides limited insight. This paper thus presents a validated coupled multiphysics model of the conventional SSTL-T50 thruster. The paper shows the preliminary results of a model for the T-50 nozzle and implements the compressible Navier-Stokes equation coupled with conductive, radiative and convective heat transfer in both solid and fluid. The CFD multiphysics model is coupled with an optimization solver, in order to converge on experimental data for the thruster. The calculated results of this nozzle are presented as centerline variations of Mach number and static temperature, with an analysis of nozzle exit profiles of Mach number and including radiation loss from the nozzle