Browsing by Subject "Space Studies"

Now showing 1 - 17 of 17
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    A fluid loop actuator for active spacecraft attitude control - A Parametric Sizing Model and the Design, Verification, Validation and Test with a Prototype on an Air Bearing
    (2019) Martens, Bas; Martinez, Peter
    Active spacecraft attitude control by using a pumped fluid as the inertial mass has potential advantages over reaction wheels, including high torque, lower power consumption, reduced jitter and prolonged lifetime. Previous work addressed conceptual and mission-specific control aspects, and one fluid loop has flown on a demonstration mission. In this dissertation, a parametric sizing model is developed that can optimize a fluid loop for any mission, based on pump capabilities and customer requirements. The model can be applied to circular, square and helical fluid loops, and includes the power consumption due to viscous friction. A configurable prototype was developed to verify the model, as well as a spherical air bearing to verify the rotational aspects of the various fluid loop configurations. The model was applied to various hypothetical missions. In conclusion, the fluid loop has the fundamental potential to replace reaction wheels in a wide variety of satellites above approximately 20 kg, if mass is carefully optimized and efforts are made to develop a suitable pump. This is considered worthwhile, as the actuator comes with many potential advantages.
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    Characterization of the Multipath Environment of Ionospheric Scintillation Receivers
    (2015) Atilaw, Tsige Yared; Cilliers, Pierre; Martinez, Peter
    Global Navigation Satellite Systems (GNSS) are used to provide information on position, time and velocity all over the world at any time of the day. Currently there are four operational GNSS and one of them is GPS (Global Positioning System) that is developed and maintained by U.S Department of Defence (DoD), which is widely used and accessible all over the world. The accuracy of the output or even the availability of the navigation system depends on current space weather conditions, which can cause random fluctuations of the phase and amplitude of the received signal, called scintillation. Interference of GNSS signals that are reflected and refracted from stationary objects on the ground, with signals that travel along a direct path via the ionosphere to the antenna, cause errors in the measured amplitude and phase. These errors are known as multipath errors and can lead to cycle slip and loss of lock on the satellite or degradation in the accuracy of position determination. High elevation cut off angles used for filtering GNSS signals, usually 15-30°, can reduce non-ionospheric interference due to multipath signals coming from the horizon. Since a fixed-elevation threshold does not take into consideration the surrounding physical environment of each GPS station, it can result in a significant loss of valuable data. Alternatively, if the fixed-elevation threshold is not high enough we run the risk of including multipath data in the analysis. In this project we characterized the multipath environment of the GPS Ionospheric Scintillation and TEC (Total Electron Content) Monitor (GISTM) receivers installed by SANSA (South African National Space Agency) at Gough Island (40:34oS and 9:88° W), Marion Island (46:87° S and 37:86° E), Hermanus (34:42° S and19:22° E) and SANAE IV (71:73° S and 2:2° W) by plotting azimuth-elevation maps of scintillation indices averaged over one year. The azimuth-elevation maps were used to identify objects that regularly scatter signals and cause high scintillation resulting from multipath effects. After identifying the multipath area from the azimuth-elevation map, an azimuth-dependent elevation threshold was developed using the MATLAB curve fitting tool. Using this method we are able to reduce the multi-path errors without losing important data. Using the azimuth-dependent elevation threshold typically gives 5 to 28% more useful data than using a 20° fixed-elevation threshold.
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    Design of the Electronics Subsystem for a High-Resolution Electro-Optical Payload Using Systems Engineering Approach
    (2022) Mehmood, Nasir; Martinez, Peter
    Satellite imagers, in contrast to commercial imagers, demand exceptional performance and operate under harsh conditions. The camera is an essential part of an Earth Observation Electro Optical (EO) payload that is designed in response to needs such as military demands, changes in world politics, inception of new technologies, operational requirements and experiments. As one of the key subsystems, the Imager Electronics Subsystem of a high-resolution EO payload plays very important role in the accomplishment of mission objectives and payload goals. Hence, these Electronics Subsystems require a special design approach optimised for their needs and meticulous characterizations of high-resolution space applications. This dissertation puts forward the argument that the system being studied is a subsystem of a larger system and that systems engineering principles can be applied to the subsystem design process also. The aim of this dissertation is to design the Imager Electronics Subsystem of a high-resolution Electro Optical Payload using a systems engineering approach to represent a logical integration and test flow using the space industry guidelines. The Imager Electronics Subsystem consists of group of elements forming the functional chain from the Image Sensors on the Focal Plane down to electrical interface to the Data Handling Unit and power interface of the satellite. This subsystem is responsible for collecting light in different spectral bands, converting this light to data of different spectral bands from image sensors for high-resolution imaging, performing operations for aligning, tagging and multiplexing along with incorporating internal and external interfaces.
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    Designing of a solar panel deployment mechanism for small satellite
    (2021) Kabir, Saqib; Martinez, Peter
    In the last few years, there has been a considerable increase of low cost space mission. Almost every small satellite has appendages like Solar Panels OR Antennas. These appendages have large inertial forces with low structural rigidity and mass to size ratio. These appendages are in stowed position in launcher to accommodate the whole satellite in the Launcher. However after launching these appendages are deployed to obtain the required power and the pointing of antennas. Their power producing capability is directly related to their area of exposure to sun, that is why these panels are available in different sizes and configurations. The requirement for the deployment mechanism for these appendages need to be cost effective, compact, lighter in weight and simple. It is entirely dependent on the structural designer to create such a robust mechanism that conforms to the requirements of the mission. In order to deploy the solar panels, it is mandatory that some sort of actuating system is employed. In this regard, we are aiming to use the torsional spring to induce the required torque for the deployment. There has been a considerable amount of research work [1-4] for a robust deployment mechanism to deploy the solar panel reliably without compromising on the overall cost and strength of the system. To realize the practical utility of Torsion Springs [5] for solar panel deployment, with the deficiency of locking after deployment and hold down mechanism when stowed. We propose a simple actuation scheme of designing the mechanism using Spiral Torsional spring for small satellite with its Zero 'g' testing and mitigation of expected Risks.
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    Evaluating the Performance of the Resampled nSight-2 Sensor's Spectral Configuration in Discriminating Wetland Plant Species Using Advanced Classifiers and Spectroscopy.
    (2022) Gasela, Mchasisi; De Jager, Gerhard; Kganyago, Mahlatse L
    Accurate and reliable information about wetland plant species is critical, as it informs improved preservation, conservation and management of wetland ecosystems. Well managed ecosystems guarantee achieving Sustainable Development Goals. Therefore, remote sensing technique has gained prominence in providing such information. However, broadband sensors are affected by effects of soil and water reflectances associated with wetlands hence cannot adequately discern subtle differences among wetland plant species. On the other hand, hyperspectral sensors allow for an in-depth examination of plant leaf and canopy biochemical traits such as lignin, cellulose, nitrogen, chlorophyll, carotenoids, anthocyanin and water content through spectral measurements which is critical for plant species discrimination. This study sought to test the capability of the forthcoming nSight-2 hyperspectral sensor in discriminating among four dominant wetland plant species. To accomplish this, the performance of nSight-2 spectral settings were compared with those of the upcoming EnMap hyperspectral satellite and an already established Worldview-2 multi-spectral sensor that carries strategic wavebands for vegetation studies, i.e. red-edge and near-infrared. The study also evaluated the performances of non-parametric machine learning algorithms in classifying wetland plant species using nSight-2 spectral configuration. The results showed a high discrimination accuracy by nSight-2 spectral settings with an overall accuracy of 84.09%, followed by Worldview-2 i.e. 81.82% while EnMap was the worst i.e. 77.77%. The most important bands for vegetation analysis were within the visible (VIS), Red-edge (RE) and near infrared (NIR) regions of the electromagnetic spectrum. The study also demonstrated that within these spectral bands, the four dominant Verloren Vallei Nature Reserve wetland plant i.e. Crocosmia sp., Grasses, Agapanthus sp. and Cyperus sp. could be differentiated using the spectral settings of these sensors. Furthermore, the results showed a superior performance of Support Vector Machine (SVM) with overall accuracy of 93.18%, compared with the RF and Partial Least Squares-Discriminant Analysis (PLS-DA) that had overall accuracies of 84.09% and 83.63% respectively. In summary, the study demonstrated that the spectral configuration of nSight-2 hyperspectral sensor can discriminate among the wetland plant species with comparable accuracy to that of a stateof-the-art sensor, i.e. Worldview-2 and better than the upcoming EnMap.
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    Firmware Design and Testing for Data Handling and Control of Time Delay Integration Image Sensors in an Earth Observation Payload
    (2022) Ahmed, Muhammad Ebtisam; Martinez, Peter
    Earth observation is becoming more and more important in this age of information. It provides critical information in every field of work be it military, scientific research, disaster management, urban planning and many others. Better planning in all these fields is possible with more detailed information which translates to a requirement of high-resolution Earth observation data. These high-resolution images tend to generate a lot of data which needs to be processed in a very short time. This high data rate problem is the focus of this work. This work tries to tackle this problem in two ways. Firstly, a Time Delay Integration (TDI) image Sensor is used which drastically improves image Signal to Noise Ratio (SNR) and decreases the amount of data generated. Secondly, an FPGA is used for data handling and processing of this generated data. The large number and high bandwidth of FPGA inputs/outputs enables it to handle huge data generated. Functional analysis and requirements of firmware design will be analyzed based on previous works addressing a similar problem. Based on that, requirements will be proposed. The firmware design of the FPGA is proposed, which drives firmware architecture. This architecture serves as a guideline for detailed firmware design which will be done in VHDL. This firmware design will be tested as per requirements and presented in this work.
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    Identification and monitoring of oil pipeline spill fire using space applications
    (2018) Gbenga, Ogungbuyi Michael; Martinez, Peter; Eckardt, Frank
    Oil pipeline spills in the Niger Delta cause a great deal of environmental damage to sensitive ecosystems and losses of many millions of dollars to the Nigerian economy every year. These spills occur along the routes of pipeline infrastructure and other oil facilities like flowlines, trunk lines, flow stations, barges, well heads etc. The causes of these spill events include: operational or maintenance error, ageing oil facilities, as well as acts of deliberate sabotage of the pipeline equipment which often result in explosions and fire outbreaks. In this project, we have investigated whether satellite observations could be used to detect these oil pipeline fires. The Nigerian National Oil Spill Detection and Response Agency (NOSDRA) database contains a total of 10 072 oil spill reports from 2007 to 2015. The space-based approach we considered in this dissertation included the use of data gathered by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra and Aqua satellites, which recorded 85 129 active fire hotspots in the Niger Delta from 2007 to 2015. Since the oil spill reports serve as validation data for these oil spill fires, we explored the capability of the MODIS instrument to study the spatio-temporal correlation between spills and fire events by attempting to investigate whether the largest spills by volume that resulted in fires could be detected from space in near-real time. Although the NOSDRA oil spill reports are plagued with several irregularities from the Joint Investigation Visits by the joint task force who visit spill sites, our approach in this dissertation automated the filtering process of the raw database to meet our research goal and objective. This study confirms that, indeed, fires resulting from oil spills are detectable using the MODIS fire products. For 43 of the largest spill events, we were able to establish a spatio-temporal correlation of spill incident reports with MODIS fires clearly associated with the oil pipeline infrastructure. Our study also shed light on the spatial and temporal characteristics of non-pipeline fires in the study area.
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    Identifying Ionospheric Scintillation in the South Atlantic Magnetic Anomaly using motion-affected GPS data from a ship-based receiver
    (2019) Vermeulen, Annelie; Cilliers, Pierre; Martinez, Peter
    his dissertation serves to report on the novel use of a geodetic-grade, dual-frequency Global Positioning System (GPS) Ionospheric Scintillation and Total Electron Content Monitor (GISTM), in an attempt to identify instances of ionospheric scintillation over the South Atlantic Magnetic Anomaly (SAMA) while located aboard the moving polar research vessel SA Agulhas II. The SAMA is a region in the South Atlantic Ocean where the Earth’s magnetic field is weakest in relation to other regions at comparable latitudes, resulting in the precipitation of high-energy particles into the ionosphere during geomagnetic storms. Ionospheric scintillations are rapid fluctuations in the phase and amplitude of trans-ionospheric radio signals resulting from electron density variations along the ray path. As a result, spacebased navigation systems can encounter increased errors in position accuracy or complete loss of lock. These are risk factors for modern aircraft and ocean vessels which rely on access to accurate Position, Navigation and Timing (PNT) services to operate safely. In this research, only the radio signals from GPS satellites are specifically used to measure these fluctuations. Traditional scintillation measurements are done using dedicated dual-frequency GPS receivers at fixed terrestrial locations. Most of the SAMA lies beyond the reach of the land-based sensors. The South African National Space Agency (SANSA) operates several GISTM stations in Southern Africa, at Marion Island, Gough Island, and the SANAE-IV base in Antarctica. The NovAtel GSV4004B GPS Ionospheric Scintillation and Total Electron Content Monitor (GISTM) installed on board the SA Agulhas II in 2012 has enabled for the first time the terrestrial measurement of scintillation from within the SAMA region. In this project, the amplitude scintillation (S4) and phase scintillation (σφ) indices from 50 Hz L1 GPS signals recorded during the 2014 and 2015 voyages of the SA Agulhas II were analysed for the first time. The scintillation effects are characterised in terms of position and motion data, carrierto-noise-density ratio, number of satellites, and satellite lock time. The goal is to develop an understanding of the effect of motion on the quality of data recorded by the receiver. The roll angle thresholds for the SA Agulhas II are calculated and it is shown that multipath errors are unlikely to be experienced. Significant data challenges were identified stemming from the incorrect setup of the SA Agulhas II GISTM. Data from elevations below 10° were missing because of hard-coded limitations within the GISTM on-board software. The data underwent significant reprocessing before being used. Comparisons were done in-harbour and out at sea with data from the nearest stationary GISTM receivers. It was shown that the movement of the receiver induces significant noise in the data. The noise levels are proportional to the velocity of the ship. An attempt to filter out the noise was unsuccessful. The motion-induced noise in the ship data masked the presence of any potential scintillations. With the ability to detect scintillation compromised, it was decided that a comparison with a land-based receiver within the SAMA would be necessary. Only one identical GISTM receiver met these requirements, located on Gough Island, at 40°20’ 58.90" S, 9°52’ 49.35" W. Data was isolated from both the SA Agulhas II GISTM and Gough Island GISTM for a period where the separation between the two receiver locations was less than 100 km. The Symmetric-Horizontal disturbance index (SYM-H) was used to identify geomagnetic storm conditions. GPS visibility maps were used to identify any potential signal obstructions. No correlation could be seen between position error and the number of satellites locked due to the high number of GPS satellites available at all times. It was discovered that the high noise levels had no effect on the position accuracy of the moving receiver, but that rapid changes in the instantaneous velocity coincided with peaks in the position error. No scintillation events were identified using the SA Agulhas II GISTM as a result of masking by the noise, however, the Gough Island GISTM data showed that no scintillation events occurred during the period in question anyway. Wind was identified as a potential contributing factor to the motion noise effect. This study provided justification for the purchase and installation of a newly developed motion-compensated GISTM receiver on board the SA Agulhas II, running off the same antenna and thus the same received signals. These data sets can be used for a direct receiver comparison in future work.
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    Investigation Of Material Properties Of Sintered Black Point-1 Lunar Regolith Simulant
    (2019) Ogunyinka, Adebayo Olutumbi; Martinez, Peter
    The quest for establishing a human presence and development beyond the Earth, especially on the moon has opened up opportunities for future plans for lunar bases and settlements. However, the cost of using resources outside the lunar environment can inhibit this form of expansion, therefore the need for In Situ Resource Utilization (ISRU). The aim of this research was to investigate the possible usage of in situ resources for lunar construction and other economic development. The study evaluated different methods of material preparation using lunar regolith simulant for structural applications on the moon. The research employed the use of the regolith simulant known as Black Point-1 (BP-1). This research work presents the methodology used in developing lunar simulant and compares the properties of BP-1 regolith simulant to those of lunar soil, in terms of geotechnical and mechanical properties. Various laboratory analyses were carried out to determine these properties with the aid of thermal and analysis, particle size distribution, and XRD experiments. Our findings show that the particle size distribution and porosity of BP-1 are similar to that of the lunar regolith. The simulant was then sieved to produce four grades of powder (38 µmm, 106 µm, 212 µm and unsieved). The graded powders were then compressed to form a series of disc-shaped green compacts for sintering. The sintered samples were then subjected to compression testing. There were four different values of average compressive strength of the porosity materials ranging from lowest to highest porosity corresponding to the smallest to largest average grain sizes of 38 µm, 106 µm, unsieved and 212µm and they were 66.14MPa, 60.47MPa, 58.52MPa, 42.74 MPa, respectively. The particle size distribution was investigated on Black Point-1 simulant to determine the effect of the porosity while the bulk properties of the material were also examined for each of the four porosity grades, and this includes toughness, Poisson ratio, bulk modulus, Young’s modulus of elasticity and compressive strength. When compared with other ISRU structural materials and published data for real lunar regolith it was observed that sintered BP-1 is sufficiently strong for lunar structural applications.
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    Low cost and portable software defined radio ground station
    (2019) Ojur, Barbara Apili; Martinez, Peter
    Small satellites are being launched by a multitude of private and public organizations around the world. They are innately cheaper than their large counterparts. This attribute, and additional ones, such as their easy-to-assemble nature and the convenience of using commercially available off-the-shelf parts to build them has enhanced their popularity. Now that getting into space has become more accessible there is an influx of information available from small satellites, however the information is not being utilized too efficiently on Earth. One reason as to why this is evident is because traditional ground stations, which are largely hardware dependent, are expensive to develop. However, with the introduction of Software Defined Radios (SDRs) many of the operations formerly done using hardware can now be implemented in software. Using a SDR can substantially reduce the cost of a traditionally hardware-based ground station. A number of universities and other organizations have or are developing SDR ground stations to communicate with satellites in different orbits. The ability to receive or transmit signals is important because it displays the capability to develop and operate satellites to various stakeholders. This dissertation attempted to enhance the movement towards satellite communication using SDR technology by developing a low cost, portable, easy to assemble and extendable ground station at the University of Cape Town in order to make contact with one or more small satellites in Low Earth Orbit (LEO), to encourage data usage, national and international collaboration and education. The ground station was constructed and tested based on its objectives, requirements and constraints. The commissioning tests were conducted in the SpaceLab at the University of Cape Town. The ground station was able to make contact with two small satellites in LEO successfully. Packets were received from two satellites that clearly stated who they were. The information contained in the packets was decoded into ASCII text and Hex code. They were compared with other successful amateur ground station results from all over the world to verify their authenticity. The main conclusion was that the SDR ground station was able to make contact with small satellites in LEO operating in the 70-cm band.
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    Mechanical Structure Design and Analysis of Focal Plane Unit (Fpu) for Earth Observation (Eo) Payload
    (2022) Anwar, Muhammad Mubeen; Martinez, Peter
    The focal plane unit plays a vital role in an earth observation payload to meet its highly demanding optical performance requirements. Focal plane unit mechanics consist of a sensor module mounting and planar optics. An image is formed on the image plane and mechanics is used to hold sensors and planar optics in place. The mechanical design of this unit is has two functions. Firstly, it ensures optical focus and alignment of the image plane in the temperature extremes of the space environment. Secondly, the mechanics also needs to handle harsh launching loads to get the satellite in space. The important constraints of this design are the mass and volume which need to be considered during the design. Optical performance depends a lot on the design of the mechanics used to support and align optical elements and image sensors. In this dissertation we perform the design of a focal plane unit using Solid Works 3D CAD modelling software. To validate the mechanical performance of our design Finite Element Analysis (FEM) analysis needs to be performed on every mechanical element with application of launch and environmental loads. Assembly and integration of the focal plane unit is also an important consideration, which if not properly done may deteriorate the performance. Therefore, the assembly and integration procedure is also highlighted in this work. These processes are presented in this work with future recommendations for future work.
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    Modelling and testing the effects of space radiation on space-borne electronic components
    (2018) Snell, Holly; Martinez, Peter; Barbard, Arno
    Outer space is a hazardous environment for satellites as they are continuously exposed to harsh space radiation in the form of cosmic rays and high-energy electrically charged particles (protons, electrons and alpha particles). Mission-critical electronic components are especially susceptible to space radiation as high-velocity charged particle impacts on molecular-sized circuitry can cause significant device upsets or permanent damage, compromising a satellite's functional integrity. In order to mitigate this radiation hazard, electronic components are carefully selected and tested prior to deployment. Part of this process involves consulting a space radiation model in order to be able to estimate the type of radiation environment the electronics will be exposed to. There are many different environmental models to choose from and the output from the models will influence whether a certain device will be selected or not. Due to this, the model selection process should be very well understood and all parameters carefully chosen. This project aims to describe the radiation environment in low Earth orbit, and to provide guidelines for using the space radiation models found on the Space ENVironment Information System (SPENVIS). By going through the modelling process in detail, we have found that the trapped radiation models are completely independent of the date specified when describing the orbit of interest. We found that all long-term solar proton models (except King) assume a zero flux for solar minimum dates. The accuracy of the model output for a specific orbit depends on the duration of the model's time span. For instance, we found that for certain low Earth orbits, the accuracy of the model output could be easily improved by increasing the number of days in the orbit generator from one to three. For the low Earth orbits we selected to analyse, we found that a one-year mission delay at any point on the solar cycle will not have great enough an effect on the output to warrant a re-calculation. It is important to consider both trapped and non-trapped radiation when calculating an upset rate and, lastly, the upset rate calculation could be altered by a factor of 1000 simply by selecting different models for the exact same device and orbit. We conclude this study with some guidelines for the use of SPENVIS for radiation modelling during mission planning.
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    On the feasibility of landing the dream chaser space vehicle in South Africa
    (2021) Colvin, Kyle Luke; Martinez, Peter
    The Dream Chaser is a space vehicle currently under development by the Sierra Nevada Corporation for purposes of carrying humans and cargo to low Earth orbit. In 2016, the United Nations entered into an agreement with Sierra Nevada Corporation to fly experimental payloads on the Dream Chaser. The collaborative UNOOSA-SNC Dream Chaser mission will be approximately two to three weeks in duration, with the Dream Chaser orbiting Earth at an altitude of 500 km with an inclination of 0 − 35◦ . This will be the first space mission dedicated to attaining the Sustainable Development Goals. In this investigation the South African space and aerospace industry is placed under the microscope for the purpose of studying the feasibility of landing the Dream Chaser Space Vehicle on South African soil. The research dictates possibly having to establish a dualuse airport/spaceport recognised by the South African Space Council under supportive legislation to support this mission. Elements addressed in this investigation range from physical facilities such as the airports, workshops and laboratories through Dream Chaser specific requirements and specifications, right down to space and civil aviation regulations. This dissertation will assess all available infrastructure and supporting entities that will facilitate the safe landing of the Dream Chaser space vehicle in South Africa. However site visits and interviews were not part of this investigation. This investigation prefaces the University of Cape Town's Space Lab plans to submit a landing proposal for a possible alternative landing site(s) for the Dream Chaser outside of the USA. This report is the first major step in researching and documenting the potential for landing the Dream Chaser or any reusable space vehicle in South Africa and will therefore make the case for South Africa as a suitable and attractive landing destination, not just for the Dream Chaser, but for accompanying scientists and researchers from all over the world involved in the mission.
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    Queue scheduling the Alan Cousins Telescope
    (2019) Maartens, Deneys Sean; Martinez, Peter
    The Alan Cousins Telescope is a 0.75-m automatic photoelectric telescope situated at the South African Astronomical Observatory, in Sutherland. The telescope was designed and built to execute a range of photometry programmes, but is used mainly for the long-term monitoring of variable stars. In addition, there is the potential for target-of-opportunity observations of unanticipated events, such as gamma ray bursts, and anticipated events such as occultations. Ultimately the telescope is intended to be a fully robotic telescope with limited operational support needs. Some advance toward this goal has been made by a full hardware interface to allow queue executions of observations. The next phase is the implementation of an automated scheduler that will generate a queue of valid observations for each night of observation. Queue scheduling algorithms are widely used in astronomy and the aim of this dissertation is to present a strawman scheduler that will generate the nightly observation queue. The main design of the scheduler is based on a merit-based system implemented at the STELLA robotic observatory, paired with the scheduling algorithms used by SOFIA. The main drawback of the telescope is that it does not currently accommodate dynamically changing weather conditions. As a consequence, the main scheduling constraints are observation parameters, instrument ability, and for monitoring type observations, observation time window constraints.
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    Space Art + Space Science a polymathic paradigm shift in the art/science dialogue
    (2020) King, Barbara Amelia; Martinez, Peter
    Perhaps no other field of scientific endeavor has been more influenced by the arts than space exploration. The artistic visions of yesteryear are the technological realities of today. These realities in turn create new possibilities for artistic expression. However, Space Art and Space Science have shared a convoluted history. Their forerunner disciplines of the Humanities and Natural Sciences and their practitioners were entrenched as polar opposites for centuries. Recent research, however, has revealed the reverse; that the psychological profile and the creative processes of artists and scientists are actually similar, often to the point of the practitioners being polymathic. Moreover, it has been discovered that polymathic ability nurtures two qualities essential for the survival of both Space Art and Space Science: that of creativity and innovation. Current literature has taken note of the commonality of polymathic ability between the practitioners of the arts and sciences. Academic and industry think tanks have examined the virtues of artists as space researchers, and conversely, scientists developing an artistic approach as a design strategy. Thought leaders have expressed faith in trans-disciplinary collaboration as the way forward in the global affairs of space. Yet, therein lies the problem. These various studies individually lack a cohesive strategy to leverage their findings and transform the Art/Sci dialogue into a disruptive force that sustains a paradigm shift in the arts, space and society agendas going forward. The impetus for this dissertation is the unique opportunity to amalgamate those disparate studies by utilizing the momentum of New Space culture, and its focus on societal inclusion and environmental concerns to serve as anchors for space research and sustainability. Further, we argue that the next logical step is to inculcate a fundamental Art/Sci paradigm shift within the space community to exploit the unprecedented global drive towards space exploration and colonization, thereby solidifying the influence of the space art and space science agendas in the service of the global commons on Earth and in space.
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    Thermal design and analysis of the SKA SA MeerKAT Digitiser
    (2018) Moss, Vaughan; Martinez, Peter
    The Square Kilometre Array Project is a multi-national venture attempting to build the world's largest radio telescope. Australia and South Africa (together with other African countries), will be host to the SKA site. Both countries are building pre-cursor radio telescopes to demonstrate their ability to successfully host the project. Square Kilometre Array South Africa (SKA SA) is currently constructing the MeerKAT Radio Telescope in the Karoo Desert. Radio telescopes are conventionally designed to have the signal Digitiser located in the pedestal of the radio telescope antenna structure to shield the incoming radio signal from being contaminated by the electromagnetic interference (EMI)/radio frequency interference (RFI) noise created by the Digitiser electronics. However, if a Digitiser could be placed near the antenna feed, this would decrease the length of the signal path between the receiver and the Digitiser, which would decrease noise on the signal. The aim of this thesis is to present a viable thermal design for an externally, near-feed mounted, passively cooled Digitiser on the MeerKAT Radio Telescope. This has never been done before. Through calculation, simulation and design iteration this aim was achieved, resulting in an operational Digitiser system which is being used on the MeerKAT Radio Telescope and could potentially also be used in SKA Phase 1.
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    The user concept in the space industry and how this frames satellite missions, with a focus on social development in Africa
    (2018) Kirkam, Kechil; Martinez, Peter
    Space-derived data lies untouched in data vaults, while many potential use cases for space applications are not exploited by the space industry. This gap may exist because the conceptualisation of the user in the satellite industry is too narrow, and yet influences the architecture and thence outcomes of a satellite mission. Assumptions about users and markets are not made on the basis of data and market research, in itself typically difficult to obtain, especially in Africa. This results in a lack of understanding of the end user and their social and economic context which feeds back to inadequately scoped requirements in satellite design. The reasons for this are not solely the limited imaginations and culture of practice of satellite engineers, but the structure of the space industry itself and its design frameworks. This limitation has impact especially for developing country applications, where the user and beneficiary concept elide in often unexamined and unchallenged ways. The satellite industry, part of the wider space industry, could borrow usefully from the IT industry in its relationship to the user and methods of deriving user requirements; in fact could consider itself part of the IT/data industry. This study explores the relationship between satellite design and the users of space-derived data, and how this is being affected by new disruptors to the traditional space industry. The implications for potential users in Africa are considered.