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Canadian Advanced Nanospace eXperiment 7 (CanX-7) Mission Analysis, Payload Design and TestingShmuel, Barbara 26 November 2012 (has links)
A deorbiting drag device is being designed and built by the University of Toronto Institute for Aerospace Studies/Space Flight Laboratory (UTIAS/SFL) to be demonstrated on the Canadian Advanced Nanospace eXperiment 7 (CanX-7) satellite. CanX-7 will address the growing issue of space debris by designing a drag sail device that will be demonstrated for cubesat-sized satellites. Mission analysis done to ensure the drag device functions properly and deorbits within the required lifetime is performed while varying different properties such as drag coefficient, effective drag area, and solar cycle variations. The design evolution of the device is documented and the chosen design, along with several stages of prototyping, is described. The individual components that make up the device are described as are preliminary numerical analyzes. Finally, the test plan required for the device is described with several deployment experiments and risk reduction tests documented.
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Canadian Advanced Nanospace eXperiment 7 (CanX-7) Mission Analysis, Payload Design and TestingShmuel, Barbara 26 November 2012 (has links)
A deorbiting drag device is being designed and built by the University of Toronto Institute for Aerospace Studies/Space Flight Laboratory (UTIAS/SFL) to be demonstrated on the Canadian Advanced Nanospace eXperiment 7 (CanX-7) satellite. CanX-7 will address the growing issue of space debris by designing a drag sail device that will be demonstrated for cubesat-sized satellites. Mission analysis done to ensure the drag device functions properly and deorbits within the required lifetime is performed while varying different properties such as drag coefficient, effective drag area, and solar cycle variations. The design evolution of the device is documented and the chosen design, along with several stages of prototyping, is described. The individual components that make up the device are described as are preliminary numerical analyzes. Finally, the test plan required for the device is described with several deployment experiments and risk reduction tests documented.
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Attitude and Orbit Control During Deorbit of Tethered Space DebrisFlodin, Linus January 2015 (has links)
Due to the unsustainable space debris environment in Low Earth Orbit, debris objects must be removed to ensure future safe satellite operations. One proposed concept for deorbiting larger space debris objects, such as decommissioned satellites or spent upper rocket stages, is to use a chaser spacecraft connected to the debris object by an elastic tether, but the required technology is immature and there is a lack of flight experience. The inoperable satellite, Envisat, has been chosen as a representative object for controlled re-entry by performing several high thrust burns. The aim of this paper is to develop a control system for the deorbit phase of such a mission. Models of the spacecraft dynamics, the tether, and sensors are developed to create a simulator. Two different tether models are considered: the massless model and the lumped mass model. A switched linear-quadratic-Gaussian (LQG) controller is designed to control the relative position of the debris object, and a switched proportional-integral-derivative (PID) controller is designed for attitude control. Feedforward compensation is used to counteract the couplings between relative position and attitude dynamics. An analysis of the system suggests that the tether should be designed in regard to the control system and it is found that the lumped mass model comes with higher cost than reward compared to the massless tether model in this case. Simulations show that the control system is able to control the system under the influence of modeling errors during a multi-burn deorbit strategy and even though more extensive models are suggested to enable assessment of the feasibility to perform this mission in reality, this study has resulted in extensive knowledge and valuable progress in the technical development. / En ökande mängd rymdskrot har lett till en ohållbar miljö i låga omloppsbanor och föremål måste nu tas bort för att säkerställa framtida satellitverksamhet. En föreslagen metod för att avlägsna större skrotföremål, såsom avvecklade satelliter och använda övre raketsteg, är att koppla en jagande rymdfarkost till föremålet med en elastisk lina. Dock är den teknik som behövs inte mogen och det finns en brist på praktisk erfarenhet. Den obrukbara satelliten Envisat har valts som representativt objekt för kontrollerat återinträde genom flera perigeumsänkande raketmanövrar. Syftet med detta arbete är att utveckla ett system för att kontrollera de två sammankopplade rymdfarkosterna under avlägsningsfasen under ett sådant uppdrag. Modeller för farkosternas dynamik, den sammankopplande linan och sensorer byggs för att utveckla en simulator. Två olika modeller för linan undersöks: den masslösa modellen och den klumpade nodmassmodellen. En omkopplande regulator designas genom minimering av kvadratiska kriterier för att kontrollera skrotföremålets relativa position till den jagande farkosten. Vidare designas en omkopplande proportionerlig-integrerande-deriverande (PID) regulator för att reglera pekningen hos den jagande farkosten. Kompensering genom framkoppling används för att motverka de korskopplingar som förekommer mellan translations- och rotationsdynamiken. En analys av systemet visar att linan bör designas med reglersystemet i åtanke och det framkommer att nackdelarna överväger fördelarna för den klumpade nodmassmodellen jämfört med den masslösa modellen. Simuleringar visar att reglersystemet klarar att kontrollera systemet under ett scenario med flera manövrar och under inverkan av modellfel. Även om mer omfattande modeller föreslås för att möjliggöra en fullständig bedömning av genomförbarheten för detta uppdrag så har denna studie resulterat i en omfattande kunskapsvinst och värdefulla framgångar i det tekniska utvecklingsarbetet.
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