BEGIN THE ADVENTURE : How to Break the Light Barrier by A.D. 2079 (3rd ed.)

This edition, the third, has undergone a subtle name change, going from A.D. 2070 in the title to A.D. 2079 as the timeline is fine-tuned. Because of the almost universal failure to recognize the distinction between physical (reality-based, dynamical) and visual (appearance-based, kinematical) variables, a tremendous volume of mythology arose over the past 100 years centered around Einstein\u27s reality view of the distortions of special relativity. To get a sense of it, we point the reader to Paul J. Nahin\u27s heroic book, Time Machines, 2nd ed.,- to these Tech Notes in particular: TN#6. A High-Speed Rocket Is a One-Way Time Machine to the Future ; TN#7. Superluminal Speeds, Backward Time Travel, and Warp Drive, or Faster-Than-Light into the Past ; TN#8. Backward Time Travel According to Gödel and Tipler. But those magical effects go away when we consider that the variables of special relativity are kinematical, not physical. If they have not yet gone away in the minds of everyone, a reason may be that there is a great need felt by many fine folk for such effects to be real. There are today sizeable popular and scientific communities with vested interests in keeping those magical hopes alive. But at some point in time humanity must come of age, question the existence of Santa Claus and come to realize that what we see is not necessarily what we get… . That the stick partly stuck in water may not be bent or broken after all even though it distinctly and definitely appears to be. Distinguished cognitive researcher Massimo Piattelli-Palmarini might characterize the period just ending as a century-long mistake of reason – a kind of mass cognitive illusion. MP-P, Inevitable Illusions/ How Mistakes of Reason Rule Our Minds, John Wiley, ISBN 0-471- 58126-7, 1994, p.18: These are errors we commit without knowing that we do so, in good faith, and errors that we often defend with vehemence, thus making our power of reasoning subservient to our illusions. Page 141: Cognitive illusions, unknown to science until some 20 years ago, are active in all of us ... Page 139: cognitive illusions are general, because they are found in all human beings. MP-P did not direct his message at Einstein; that is my doing. Yet the descriptions MP-P gives seem to fit the present context

A comparison of processing techniques for producing prototype injection moulding inserts.

This project involves the investigation of processing techniques for producing low-cost moulding inserts used in the particulate injection moulding (PIM) process. Prototype moulds were made from both additive and subtractive processes as well as a combination of the two. The general motivation for this was to reduce the entry cost of users when considering PIM. PIM cavity inserts were first made by conventional machining from a polymer block using the pocket NC desktop mill. PIM cavity inserts were also made by fused filament deposition modelling using the Tiertime UP plus 3D printer. The injection moulding trials manifested in surface finish and part removal defects. The feedstock was a titanium metal blend which is brittle in comparison to commodity polymers. That in combination with the mesoscale features, small cross-sections and complex geometries were considered the main problems. For both processing methods, fixes were identified and made to test the theory. These consisted of a blended approach that saw a combination of both the additive and subtractive processes being used. The parts produced from the three processing methods are investigated and their respective merits and issues are discussed

Reducing risk in pre-production investigations through undergraduate engineering projects.

This poster is the culmination of final year Bachelor of Engineering Technology (B.Eng.Tech) student projects in 2017 and 2018. The B.Eng.Tech is a level seven qualification that aligns with the Sydney accord for a three-year engineering degree and hence is internationally benchmarked. The enabling mechanism of these projects is the industry connectivity that creates real-world projects and highlights the benefits of the investigation of process at the technologist level. The methodologies we use are basic and transparent, with enough depth of technical knowledge to ensure the industry partners gain from the collaboration process. The process we use minimizes the disconnect between the student and the industry supervisor while maintaining the academic freedom of the student and the commercial sensitivities of the supervisor. The general motivation for this approach is the reduction of the entry cost of the industry to enable consideration of new technologies and thereby reducing risk to core business and shareholder profits. The poster presents several images and interpretive dialogue to explain the positive and negative aspects of the student process

Motivation for Air-Launch: Past, Present, and Future

Air-launch is defined as two or more air-vehicles joined and working together, that eventually separate in flight, and that have a combined performance greater than the sum of the individual parts. The use of the air-launch concept has taken many forms across civil, commercial, and military contexts throughout the history of aviation. Air-launch techniques have been applied for entertainment, movement of materiel and personnel, efficient execution of aeronautical research, increasing aircraft range, and enabling flexible and efficient launch of space vehicles. For each air-launch application identified in the paper, the motivation for that application is discussed

Numerical and Experimental Investigation of Hybrid Rocket Motors Transient Behavior

As the space business is shifting from pure performances to affordability a renewed interest is growing about hybrid rocket propulsion. Hybrid rocket motors are attractive for their inherent advantages like simplicity, reliability, safety and reduced costs. Moreover hybrid motors are easy to throttle and thus they are ideal candidate when soft-landing or energy management capabilities are required. This thesis is mainly involved with a theoretical/numerical study of hybrid transient behavior. The study of transient behavior is a very important aspect in the development of affordable, efficient, stable hybrid motors, particularly when throttling and controllability is concerned. Moreover transient behavior is important also for motors that work at a fixed operating point, not only in the prediction of ignition and shutdown phases but particularly in the analysis of instabilities. The prediction and reduction of instabilities are one of the main challenge in hybrid propulsion (as in general in all rocket motors). The aim of this doctoral thesis is to investigate and simulate hybrid rocket transient behavior through the development of a numerical code. The numerical code is composed by several independent parts coupled together, each one referring to a different subsystem of the hybrid rocket motor. Due to budget and time constraints it has not been possible to perform a dedicated experimental activity for this thesis. However the numerical results have been compared with experimental data obtained from literature, from CISAS partners (like NAMMO), and from other CISAS experimental activities performed both before and during this doctoral period. Each subsystem of the hybrid propulsion unit and its related codes are described in a different chapter. In the first chapter hybrid boundary layer steady combustion is introduced together with a discussion about the effect of steady hybrid regression physics on the shift of motor operating parameters with time. In the second chapter typical necessary or intentional transient events occurring during the operation of a hybrid rocket (ignition, throttling and shutdown) are classified and described. With chapter 3 begins the description of the several sub-models defining hybrid rocket transient behavior. In this chapter the attention is focused on the numerical modeling of the solid grain thermal behavior. The main object of this work is to determine the response of the solid fuel to variations of the heat flux on the surface. A 1D numerical model of transient grain thermal response has been developed with this goal. The model is based on the work performed by Karabeyoglu and solves the temperature profile in the direction normal to the surface. In the first paragraph a model suited for classical polymeric fuels is developed. In the second paragraph the grain model is coupled with the boundary layer response in order to investigate typical hybrid low frequency instabilities. In the third paragraph a version of the original grain model suited for liquefying propellants is developed. In fact recently a new class of fast burning fuels has been discovered at Stanford University. These fuels form a liquid layer on the melting surface during combustion, hence the term 'liquefying fuels'. Entrainment of droplets from the liquid-gas interface creates the desired high regression rate by increasing the rate of fuel mass transfer. Several researchers included people at CISAS have experimental confirmed that paraffin-based fuels burn at surface regression rates 3 to 4 times that of conventional hybrid fuels. Others following studies showed with the use of visualization experiments the presences of waves on the liquid surfaces and droplets entrained by the gas flow, confirming original theoretical predictions. The third paragraph is divided in three parts. In the first part the model developed to predict the regression rate and the thermal profile inside a paraffin fuel is presented. The second part deals with the phenomenology of supercritical entrainment. Finally the third part discusses the problem of the closure of the equations to take into account the space-time variability of the entrainment phenomenon. In chapter 4 the attention is focused on the gas dynamic inside the hybrid combustion chamber. For this purpose two time-varying numerical models are developed. The aim of these unsteady codes is to determine the transient behavior of the main parameters of the hybrid rocket motor. The combustion chamber model represents the core of the hybrid rocket motor simulation. In fact the combustion chamber model gives directly the main parameter of a propulsion system, that is, motor thrust. The sub-models presented in the previous and the next chapters define the input parameters for the combustion chamber model. In fact the grain model of chapter 3 determine the fuel mass flow while the tank and feed lines model of chapter 5 gives the oxidizer mass flow. In the first part of this chapter a global 0D time-varying numerical model of the combustion chamber is developed. The code is then coupled with the grain model described in the previous chapter to account for the transient fuel production. It follows a brief discussion about the main hybrid rocket motor characteristic times and their relative values. In the second part a 1D time-varying numerical model of the combustion chamber is developed. The unsteady 1D code is able to simulate all the features of the 0D code. It should add the acoustic response of the system and the spatial variation of the fluid-dynamic unknowns along the flow direction, increasing the accuracy of the results at the expense of an higher computational effort. Chapter 5 end the description of the several sub-models of the hybrid rocket propulsion system. Together with chapter 3 and 4 it composes the code describing hybrid rocket transient behavior. In this chapter the attention is focused on the numerical modeling of the oxidizer path. This includes the sub-systems ahead of the combustion chamber like the pressurization system, the main tank and the feed lines. Moreover it considers also the injector elements and some aspects of droplets vaporization and atomization in the combustion chamber. This work is complementary to the one described in chapter 3, defining the input parameters for the core of the code, that is the chamber gas-dynamic model shown in chapter 4. The main object of this work is to determine how the feed system affects the performance parameters of the hybrid motor with time. For this purpose the prediction of several unknowns like the oxidizer mass flow, tank pressure and the amount of residual gases is obtained through the modeling of the principal subsystem behavior. Moreover the full transient coupling between the feed system and the combustion chamber is also investigated. This chapter is divided in three parts. The topic of the first paragraph regards the main tank and the pressurization system. After a brief description of the main alternatives the discussion goes on with the numerical modeling of the typical solutions adopted for hybrid rockets (i.e. pressure-regulated, blowdown and self-press). First of all a numerical model of a pressure fed tank is developed. The code is able to predict several parameters like masses, densities, temperatures and pressures of the gas in the ullage volume and in the pressurant tank, the pressurant mass flow and the filling level of the tank. The model takes into account several aspects like heat losses, liquid oxidizer evaporation, eventual gas phase combustion of the pressurant gas, the use of by-pass and digital valves. Later a numerical model of a self pressurized tank is developed. The code is able to determine the oxidizer mass, temperature, pressure, density and the vapor/liquid volume/mass fractions during the discharge. The numerical results are compared with experimental hot tests performed at CISAS. The second paragraph takes into account the full transient coupling between the feed system and the combustion chamber. The main challenge is to determine the instantaneous liquid mass flow and the relation between the liquid oxidizer and the gaseous oxidizer that takes part in the hybrid motor combustion processes (i.e. droplets vaporization). In this way it is possible to simulate feed system coupled instabilities. The third paragraph deals with the prediction of the mass flow through the injector elements. In particular the behavior of self-pressurized systems is investigated. In this case the chamber pressure is below the vapor pressure of the liquid inside the tank. Consequently cavitation and flashing occur inside the injector elements. This kind of two-phase flow with vaporization involves several important modeling issues. Different models are compared with cold-flow tests performed at CISAS in order to check the accuracy of their predictions. In chapter 6 some advanced techniques developed to increase the regression rate and combustion efficiency of hybrid rockets are investigated with a particular focus on their influence on the transient behavior of the motor, particularly regarding combustion instabilities. The two methods studied in this thesis are the use of a diaphragm in the midst of the grain and the use of a swirling oxidizer injection. The reason for this choice is related to the fact that both solutions have been tested (among others) at CISAS and look very promising with respect to the overcoming of historical hybrid weaknesses. Even if working in very different ways both methods induce a strong increase of the turbulence level and mixing of the reactants in the combustion chamber, promoting a more complete combustion and an higher heat flux on the grain surface. Beside improving significantly hybrid performances this two techniques can affect the stability behavior of an hybrid motor directly (i.e. modifying the flowfield in the chamber) and indirectly (e.g. reducing the chamber length due to increased regression rate). In the final chapter a summary of the activities carried out and the results achieved is given

Feasibility study of high precision triaxial attitude control for spacecraft Final report

Feasibility study of high precision triaxial attitude control system for future spacecraf

Spinoff 1997: 25 Years of Reporting Down-to-Earth Benefits

The 25th annual issue of NASA's report on technology transfer and research and development (R&D) from its ten field centers is presented. The publication is divided into three sections. Section 1 comprises a summary of R&D over the last 25 years. Section 2 presents details of the mechanisms NASA uses to transfer technology to private industry as well as the assistance NASA provides in commercialization efforts. Section 3, which is the focal point of the publication, features success stories of manufacturers and entrepreneurs in developing commercial products and services that improve the economy and life in general

Wings in Orbit: Scientific and Engineering Legacies of the Space Shuttle, 1971-2010

The Space Shuttle is an engineering marvel perhaps only exceeded by the station itself. The shuttle was based on the technology of the 1960s and early 1970s. It had to overcome significant challenges to make it reusable. Perhaps the greatest challenges were the main engines and the Thermal Protection System. The program has seen terrible tragedy in its 3 decades of operation, yet it has also seen marvelous success. One of the most notable successes is the Hubble Space Telescope, a program that would have been a failure without the shuttle's capability to rendezvous, capture, repair, as well as upgrade. Now Hubble is a shining example of success admired by people around the world. As the program comes to a close, it is important to capture the legacy of the shuttle for future generations. That is what "Wings In Orbit" does for space fans, students, engineers, and scientists. This book, written by the men and women who made the program possible, will serve as an excellent reference for building future space vehicles. We are proud to have played a small part in making it happen. Our journey to document the scientific and engineering accomplishments of this magnificent winged vehicle began with an audacious proposal: to capture the passion of those who devoted their energies to its success while answering the question "What are the most significant accomplishments?" of the longestoperating human spaceflight program in our nation s history. This is intended to be an honest, accurate, and easily understandable account of the research and innovation accomplished during the era

12th EASN International Conference on "Innovation in Aviation & Space for opening New Horizons"

Epoxy resins show a combination of thermal stability, good mechanical performance, and durability, which make these materials suitable for many applications in the Aerospace industry. Different types of curing agents can be utilized for curing epoxy systems. The use of aliphatic amines as curing agent is preferable over the toxic aromatic ones, though their incorporation increases the flammability of the resin. Recently, we have developed different hybrid strategies, where the sol-gel technique has been exploited in combination with two DOPO-based flame retardants and other synergists or the use of humic acid and ammonium polyphosphate to achieve non-dripping V-0 classification in UL 94 vertical flame spread tests, with low phosphorous loadings (e.g., 1-2 wt%). These strategies improved the flame retardancy of the epoxy matrix, without any detrimental impact on the mechanical and thermal properties of the composites. Finally, the formation of a hybrid silica-epoxy network accounted for the establishment of tailored interphases, due to a better dispersion of more polar additives in the hydrophobic resin