Development of an autonomous deorbiting device for a CubeSat

Thesis (MEng)--Stellenbosch University, 2020.ENGLISH ABSTRACT: The CubeSat industry is a budding one in the space sector. CubeSats are quickly becoming the satellite of choice for many Earth Observation missions and even interplanetary missions. With the CubeSats chiefly launched to Low Earth Orbit, the problem of overcrowding this space is looming. Low Earth Orbit is home to many larger satellites and is littered with space debris. If these CubeSats continue to be launched at the rate that they are currently being launched at, there will be a severe problem in a few years when they are non-functional and stuck in orbit. Collisions between space objects creates thousands of smaller pieces of debris which exponentially increases the probability of more collisions. It is, therefore, necessary to implement a plan to prevent more debris from forming in Low Earth Orbit, to prevent the runaway scenario of debris formations as well as to keep the space available for new satellites to be launched in future. This thesis focuses on the design and implementation of a CubeSat deorbiting device to be placed in the CubeSat for use at the end of its mission lifetime. First, a literature review and any theoretical knowledge needed for this project are given. A low-power hardware prototype is then designed and implemented in both vacuum chamber and atmospheric level tests. Simulations are done in MATLAB and Simulink to determine the size of the deorbit device needed for different CubeSat sizes and orbit heights. The simulations also include different device designs and satellite attitude states. Finally, the hardware tests' results are discussed and the different simulations compared.AFRIKAANSE OPSOMMING: Die CubeSat-industrie is 'n ontluikende industrie in die ruimtesektor. CubeSats word vinnig die gekose satelliet vir baie Aardwaarnemings-missies en selfs interplanetêre missies. Met die CubeSats wat hoofsaaklik na Lae Aard-wentelbane gelanseer is, is die probleem om die ruimte te oorbevolk 'n bedreiging. Lae Aard-wentelbane is die tuiste van baie groter satelliete en baie ruimterommel. As hierdie CubeSats steeds gelanseer word teen die tempo waarteen hulle tans gelanseer word, sal daar oor 'n paar jaar 'n ernstige probleem wees wanneer hulle nie funksioneel is nie en in die ruimte beset. Botsings tussen ruimte-voorwerpe skep duisende kleiner stukke rommel wat eksponensieel die waarskynlikheid van meer botsings verhoog. Dit is dus nodig om 'n plan in werking te stel om te voorkom dat meer rommel in die Lae Aarde-wentelbaan vorm, om die wegholscenario van rommelformasies te voorkom, asook om die ruimte beskikbaar te stel vir nuwe satelliete wat in die toekoms gelanseer kan word. Hierdie tesis fokus op die ontwerp en implementering van 'n CubeSat-ontwentelapparaat wat in die CubeSat geplaas moet word vir gebruik aan die einde van sy lewensduur. Eerstens word 'n literatuuroorsig en alle teoretiese kennis wat vir hierdie projek benodig word, gegee. Daarna word 'n lae-krag hardeware prototipe ontwerp en geïmplementeer in vakuumtenk en atmosferiese toetse. Simulasies word in MATLAB en Simulink gedoen om die grootte van die ontwentelsapparaat wat benodig word vir verskillende CubeSatgroottes en wentelbaanhoogtes te bepaal. Die simulasies bevat ook verskillende apparaatontwerpe en toestande vir satellietoriëntasie. Laastens word die resultate van die hardewaretoetse bespreek en die verskillende simulasies vergelyk.Master