This master's thesis presents a study on a slot and microstrip patch as the two main types of antennas for the use on Cube Satellite (CubeSat). A study on the fundamentals of the slot antenna is researched and a circularly polarized (CPd) cavity-backed cross slot antenna and its two-element array for the CubeSat are designed and fabricated. Fabricated two-element phased array cross slot antenna has higher radiation gain and steered radiation pattern compared to the fabricated single cross slot antenna. A CPd square microstrip patch antenna for the application of the CubeSat is designed and compared with a commercial CPd microstrip patch antenna. It is concluded that our designed microstrip patch antenna has a better performance compared to the commercial one. The last part of the research focuses on the design of miniaturized slot antennas for the CubeSat working at an ultra high frequency (UHF) band. The different techniques and challenges that we face through the miniaturization are articulated throughout the research and expanded upon in this thesis. The antenna simulations were performed using Ansoft High Frequency System Simula- tor (HFSS) and the final designs for the CPd cavity-backed single and two-element cross slot antennas and CPd microstrip patch antenna were fabricated using a circuit board milling machine. These were then measured inside an anechoic chamber for the radiation pattern. Both antennas had high radiation gain and good CPd radiation quality.

This thesis work presents an innovative solution for small satellite antennas by integrating slot antennas and solar cells on the same panel to save small satellite surface real estate and to replace deployed wire antennas for certain operational frequencies. The two main advantages of the proposed antenna are: 1) the antenna does not require an expensive deployment mechanism that is required by dipole antennas; 2) the antenna does not occupy as much valuable surface real estate as patch antennas. The antenna design is based on using the spacing between the solar cells to etch slots in these spaces to create radiating elements. The initial feasibility study shows it is realistic to design cavit-backed slot antennas directly on a solar panel of a cube satellite. Due to the volume of the satellite, it is convenient to design antennas at S band or higher frequencies. Although it is possible to design integrated solar panel antennas in lower frequencies, such research is not the scope of this thesis work. In order to demonstrate and validate the design method, three fully integrated solar panel antennas were prototyped using Printed Circuit Board (PCB) technology (PCB is a common solar panel material for small satellites). The first prototype is a circularly polarized antenna. The second is a linearly polarized two-element antenna array. The third prototype is a dual band linearly polarized antenna array. Measured results agree well with simulations performed using Ansoft's High Frequency Structure Simulater (HFSS). The thesis also presents a feasibility study of optimization methods and reconfigurable solar panel antenna arrays. The optimization study explores methods to use genetic algorithms to find optimal antenna geometry and location. The reconfigurable study focuses on achieving different antenna patterns by switching on and off the slot elements placed around the solar cells on solar panels of a cube satellite. It is shown that the proposed integrated solar panel antenna is a robust and cost-effective antenna solution for small satellites. It is also shown that given a solar panel with reasonable size, one can easily achieve multiple antenna patterns and polarization by simple switching.

Thesis (MEng (Mechanical Engineering))--Cape Peninsula University of Technology, 2019 / The accumulating space debris has been a developing problem for many years. Technological advances led to the creation of nanosatellites, which allows more affordable access to space. As a result, the number of satellite launches is rapidly increasing, which, translates into an increase in debris in the low earth orbit (LEO) and geostationary orbit (GEO). To comply with the Inter-Agency Space Debris Coordination Committee (IADC) requirement of a 25-year maximum orbital lifetime, nanosatellites must have an end of life strategy. Failure to meet these guidelines may not only cause catastrophic collisions but may make future space travel even more challenging. Consequently, orbital lifetime predictions must be completed for nanosatellites. Considering this, the aim of this thesis is to investigate the orbital lifetime predictions for the nanosatellite ZACube-2, and the effects on the orbital lifetime if ZACube-2 is fitted with deorbiting technology, specifically a drag argumentation device. An in-depth literature review regarding the current state of technology pertaining to nanosatellite de-orbiting was conducted. This was followed by studies regarding orbital dynamics and perturbation forces. Four case studies were simulated in NASA’s Debris assessment software (DAS 2.0) using orbital parameters extracted from the two-line element (TLE) file. General information such as launch date and final mass was provided by F’SATI. The Baseline case study presented the orbital lifetime of ZACube-2, without any drag enhancement device. This was followed by case study 1,2 and 3 which represented ZACube-2 when fitted with three different drag enhancement devices. A comparison study indicated a reduction in all three cases. A new inflatable cube de-orbiting device (ICDD) concept was also presented, and the effects it has on the orbital lifetime predictions are showcased in case study three. Two deployment concepts were considered and evaluated against design requirements. Solidworks software was used to model the most suitable concept as well as perform finite element analysis on the structure. Static analysis was followed by natural frequency analysis in which the natural frequencies of the components and assembled structure were extracted. The Soyuz launch vehicle’s sinusoidal testing requirements were used to evaluate the structures survivability under dynamic loading. Based on the finite element , and harmonic analysis it was concluded that the structures will survive the launch conditions of the Soyuz launch vehicle. Furthermore, individual parameters affecting orbital lifetime predictions are also identified, in the form of a mass and cross-sectional sensitivity study and a ballistic coefficient versus orbital time study.

The Auroral Acceleration Region (AAR) is a key region in understanding the interactionbetween the Magnetosphere and Ionosphere. To understand the physical, spatial, and temporal features of the region, multi-point measurements are required. Distributed small-satellite missions such as constellations of multiple nano satellites (for example multi-unit CubeSats) would enable such type of measurements. The capabilities of such a mission will highly depend on the number of satellites - one reason that makes low-cost platforms like CubeSats a very promising choice. In a previous study, the state-of-the-art of miniaturized payloads for AAR measurements was analyzed and evaluated on the capabilities of different multi-CubeSat configurations equipped with such payloads in addressing different open questions in AAR. This thesis will provide the mission analysis of such a multi-CubeSat mission to the AAR and possible mission design. This includes defining the mission scenario and associated requirements, developing a mathematical description of AAR that allows for specific regions in space to be targeted, an optimisation process for designing orbits targeting these regions, conversion of a satellite formation to appropriate orbits, verifying the scientific performance of this formation and the various costs associated with entering, maintaining, and exiting these orbits.