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Supersonic Retro Propulsion Flight Vehicle Engineering of a Human Mission to MarsMarklund, Hanna January 2019 (has links)
A manned Mars mission will require a substantial increase in landed mass compared to previous robotic missions, beyond the capabilities of current Entry Descent and Landing, EDL, technologies, such as blunt-body aeroshells and supersonic disk-gap-band parachutes. The heaviest payload successfully landed on Mars to date is the Mars Science Laboratory which delivered the Curiosity rover with an approximate mass of 900 kg. For a human mission, a payload of magnitude 30-50 times heavier will need to reach the surface in a secure manner. According to the Global Exploration Roadmap, GER, a Human Mission to Mars, HMM, is planned to take place after year 2030. To prepare for such an event several technologies need maturing and development, one of them is to be able to use and accurately asses the performance of Supersonic Retro Propulsion, SRP, another is to be able to use inflatable heat shields. This internal study conducted at the European Space Agency, ESA, is a first investigation focusing on the Entry Descent and Landing, EDL, sequence of a manned Mars lander utilising an inflatable heatshield and SRP, which are both potential technologies for enabling future landings of heavy payloads on the planet. The thesis covers the areas of aerodynamics and propulsion coupled together to achieve a design, which considers the flight envelope constraints imposed on human missions. The descent has five different phases and they are defined as circular orbit, hypersonic entry, supersonic retropropulsion, vertical turn manoeuvre and soft landing. The focus of this thesis is on one of the phases, the SRP phase. The study is carried out with the retro-thrust profile and SRP phase initiation Mach number as parameters. Aerodynamic data in the hyper and supersonic regime are generated using Computational Fluid Dynamics, CFD, to accurately assess the retropropulsive performance. The basic concept and initial sizing of the manned Mars lander builds on a preliminary technical report from ESA, the Mission Scenarios and Vehicle Design Document. The overall optimisation process has three parts and is based on iterations between the vehicle design, CFD computations in the software DLR-Tau and trajectory planning in the software ASTOS. Two of those parts are studied, the vehicle design and the CFD,to optimise and evaluate the feasibility of SRP during the descent and test the design parameters of the vehicle. This approach is novel, the efficiency and accuracy of the method itself is discussed and evaluated. Initially the exterior vehicle Computer Aided Design, CAD, model is created, based on the Mission Scenarios and Vehicle Design Document, however updated and furthered. The propulsion system is modelled and evaluated using EcosimPRO where the nozzle characteristics, pressure levels and chemistry are defined, and later incorporated in the CAD model. The first iteration of the CFD part has an SRP range between Mach 7 and 2, which results in an evaluation of five points on the trajectory. The thrust levels, the corresponding velocity, altitude and atmospheric properties at those points can then be evaluated and later incorporated in ASTOS. ASTOS, in turn, can simulate the full trajectory from orbit to landing including the CFD data of the SRP phase. Due to time limitation only one iteration of the vehicle design and the SRP range was completed. However, the goals of the study were reached. A first assessment of SRP in Mars atmosphere has been carried out, and the aerodynamic and propulsive data has been collected to be built on in the future. The results indicate that the engines can start at a velocity of Mach 7. They also show consistency with similar studies conducted in Earths atmosphere. The current vehicle design, propulsion system and SRP range can now be furthered, updated and advanced in order to optimise the different descent phases in combination with future results from ASTOS.
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The ‘Third Wave’ Religious Right Movement and the growth of Zimbabwean Christianity : faith or economic response?Mpofu, Sifiso January 2013 (has links)
This thesis is an historical analytical investigation and theological analysis
of the fundamental trends of the ‘Third Wave’ Religious Right Movement and
the growth of Zimbabwean Christianity. In an attempt to understand the
appealing and growth factors of this religious movement in the Zimbabwean
Church scene, the research focuses on the trends and behaviour of the
Third Wave Religious Right Movement in Zimbabwe and the critical aspect of
how this religious movement communicates the Christian faith to its
audience. A critical thrust of the study is the question of whether the
disciples of the charismatic movement are motivated by faith or economic
factors which may ultimately not be the authentic summons of the gospel of
Jesus Christ. The research addresses fears and suspicions of many
Christians who are caught up between faith and fear response to the
proclamation of the Gospel of Jesus Christ by the New Religious Right
Movements, particularly in Zimbabwe.
The hypothetical statement of this work is that there seems to be a subtle
reconstruction identity in the theology of the “Third Wave” Religious Right
Movement as is clearly manifested through the maneuverings of Christians
from the ‘traditional churches’ to these ‘newer charismatic churches in
trends which reflect the changing religious geography and the face of African
Christianity in general and Zimbabwean Christianity in particular. The
research explores the nature, impact and significance of the post – modern ‘Third Wave’ Religious Right Movement in Zimbabwean society in particular.
The identity and nature of the ‘Third Wave’ Religious Right Movement in its
historical perspective discussed by means of identifying and analyzing the
characteristics of this movement and its theological perspectives as well as
discussing the factors that promote the growth of the movement in the
context of Missio Dei (God’s Mission) and the society in general. Critical to
this type of Christianity are the images of power and prosperity which are
understood as signs of faith. The impact and effects of this type of faith
expression in the socio-political landscape is fully explored.
The primary methodology in this study is the historical critical method
complimented by oral historiography. Both primary and secondary sources
are utilized in this research in a holistic framework for analyzing the
historical trends as they unfold in the context of religious declarations and
transformations that are part of the phenomenon under investigation. The
study observes the translation model of evangelization in the unfolding
discourse of the ‘Third Wave’ Religious Right Movement.
The study ultimately reveals how people’s economic fears and hopes in the
midst of life’s challenges draw them toward religious movements which
promise to positively promote a glorious life with practical results being
realized “here and now”. This study has clearly exposed how religion,
specifically charismatic Christianity, is seen as a package of an abundant life in the context of humanity’s needs and challenges. There is a clear obsession, in the charismatic New Religious Right Movement, with wealth
and health as pedestals of salvation and a faithful Christian life.
Surprisingly, there is very little reference to moral and ethical issues from
the charismatic prophets who are the founders of these New Right
Movements. The research notes that the interests of these newer right
movements are in prosperity and health: “signs of being saved and blessed”.
Lack of economic success is blamed on demons which also causes poor
health hence the need to denounce the powers of Satan and engage on “the
heavenly gear”. Such teachings have conditioned the prospective converts to
seek after material benefits and values as critical aspects of the meaning of
salvation and the mission of Christ.
The study further reveals that the ‘Third Wave Religious Right Movement
promotes a subtle way of making disciples instead of the traditional way of
faith response to the gospel proclamation. But does this charismatic
religious life have any relevance to our human situation today? The seven
compelling chapters of this study have tackled this question and many
others, pointing the way to an authentic Christian mission that is alive and
relevant to the meaning of salvation in the context of orthodox Christianity.
This study concludes that the Church is a catalyst which carries the keys of
salvation to bring meaning and solutions to the varied human fears and
failures that characterise the temporary nature of human existence. But in
doing so; the Church must act in spirit of orthodox Christianity which is the
sine qua non of salvation. / Thesis (PhD)--University of Pretoria, 2013. / gm2014 / Church History and Church Policy / unrestricted
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