This thesis provides a multi-pronged approach towards paving the way for future space and ground based exoplanet characterisation e↵orts as well as providing new analysis of the atmosphere of the exoplanet HD 179949 b. This is done, firstly, by outlining engineering trade studies conducted for the attitude and orbit control system (AOCS) and sun shield for the Exoplanet Characterisation Observatory (EChO) spacecraft (a proposed European Space Agency exoplanet space mission). These trade studies were conducted in collaboration with EADS Astrium. A cold gas system with the possibility of a hybrid system which would include the use of reaction wheels is recommend for the design of the AOCS. For the sun shield, a V-groove cone shield is concluded to provide the best thermal coverage while also providing stay light protection as well as being more mechanically symmetric than other options. Simulations are then conducted to determine the number of transiting planets future surveys should expect to find around stars within 50 parsecs of the sun. This is done by taking the known stars within 50 parsecs and adding a simulated planet population based on current models and observations to each star. Assumptions are made regarding observability of a planetary transit and a Monte Carlo simulation run to gain statistics on the number and type of planetary systems that can be expected to be found. The results of the simulation show a mean expected number of 27 detectable transiting planets within 50 parsecs. Next, using the Position and Proper Motion Extended-L (PPMXL) catalogue, optical and near-infrared colour cuts were used together with a reduced proper motion cut to find bright M dwarfs for future exoplanet transit studies. PPMXL’s low proper motion uncertainties allow this work to probe down to smaller proper motions than previous similar studies. Unique objects found with this method were combined with that of previous work to produce 8479 K < 9 M dwarfs. Low-resolution spectroscopy was obtained of a sample of the objects found using this selection method to gain statistics on their spectral type and physical properties. Results show a spectral-type range of K7-M4V. This catalogue is the most complete collection of K < 9 M dwarfs currently available and is made available here. High resolution spectroscopy and model spectra of planetary atmospheres is then used along with a spectral deconvolution technique to attempt to detect the Doppler shifted signal of the non-transiting planet HD 179949 b. The signal was not detected but new upper limits were set ruling out the presence of TiO down to a log10 ✏0 = -4.09 with 99.9 per cent confidence. Simulations conducted by this work imply a loss of sensitivity occurring possibly due to varying telluric interference or instrumental systematics.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: Keywords: digital signal processing, embedded systems, telecommunications, satellite technology. The rapid growth of the telecommunications industry is a worldwide phenomenon with people and computers generating and transmitting more and more information daily. Despite this growth, there are still areas in South Africa which lack terrestrial communications coverage. People inhabit these rural areas and their essential communication needs are not met. Satellite based communication coverage can provide a valuable service in these circumstances. In this thesis, the design of a satellite-based communications payload which makes use of software de ned radio techniques is presented in terms of the Open Systems Interconnect layer structure. A robust hardware platform using a space-quali ed on-board computer, a Xilinx Virtex-5 Field Programmable Gate Array (FPGA) and a Freescale digital signal processor (DSP) is designed, implemented and thoroughly tested. A device driver is designed for hardware and rmware components. A prototype ground station is also designed and constructed using a low-power PC, a Xilinx Spartan-3E FPGA, a Freescale DSP and radio frequency hardware. A wide range of testing methodologies were successfully utilised to deploy a functional system which is critically evaluated in the last chapter. / AFRIKAANSE OPSOMMING: Sleutelwoorde: syferseinverwerking, toegewyde stelsels, telekommunikasie, satelliettegnologie. Die vinnig groeiende telekommunikasieindustrie is 'n wêreldwye verskynsel waarin mense en rekenaars daagliks meer en meer data genereer. Ten spyte van die groei, is daar nog steeds gebiede in Suid-Afrika wat aan 'n gebrek van aardse kommunikasiedekking lei. Mense bewoon dié areas maar daar word nie aan hul noodsaaklike kommunikasiebehoeftes voldoen nie. Satelliet-gebaseerde kommunikasiedekking kan 'n waardevolle diens in hierdie omstandighede wees. Hierdie tesis beskryf die ontwerp van 'n ruimtegebaseerde kommunikasieloonvrag wat gebruik maak van sagteware-gede nieerde radiotegnieke aangebied in terme van die Open Systems Interconnect laagstruktuur. 'n Robuuste apparatuurplatform wat gebruik maak van 'n ruimte-gekwali seerde rekenaar, 'n Xilinx Virtex-5 Veldprogrameerbare Hek-Skikking (VPHS) en 'n Freescale syferseinverwerker is ontwerp, geïmplementeer en deeglik getoets. 'n Toestelbestuurder moes ontwerp word vir die apparatuur- en fermatuur-komponente. 'n Prototipe grondstasie is ook ontwerp en gebou met behulp van' n lae-krag PC, 'n Xilinx Spartan-3E VPHS, 'n Freescale seinverwerker en radiofrekwensie apparatuur. 'n Wye verskeidenheid van toetsmetodes is suksesvol benut om 'n funksionele stelsel te ontwikkel wat krities geëvalueer word in die laaste hoofstuk.