In Orbit Servicing Missions are a category of missions which enable the servicing of in orbit satellites, by performing tasks such as orbit relocation, inspection, refuelling and repairing. DOCKS is a docking mechanism for use on small satellites, developed in the framework of SR missions, developed by a collaboration between Tyvak, PoliTo, Unipd and Stellar Project, under contract with the European Space Agency (ESA). Space Rider Observer Cube (SROC) is a 12 U CubeSat, whose target is performing an inspection mission on Space Rider, a space vehicle in a Low Earth Orbit. DOCKS is the docking mechanism which enabled SROC re-entry in SR once, its mission is concluded. The department of Industrial Engineering of the University of Padua is developing the docking mechanism, which is made up of two parts. The active part of the docking system (DOCKS-A) will be mounted on SROC, while the cooperative passive part (DOCKS-B) will be mounted on The CubeSat dispenser contained in SR. DOCKS-A is equipped with a set of 4 sensors, to collect the measures of DOCKS-B position and orientation. The 4 sensors are a NavCam, 4 Time of Flight Distance Sensors, a matrix and an IMU, which are used in various configuration in the different phases of the approach. The Preliminary Design Review has the task of performing tests on DOCKS. In detail, this thesis will describe the Thermal-Vacuum tests performed at a component level and the Navigation Algorithm Tests performed on the navigation algorithm. The Thermal-Vacuum tests performed in a thermal-vacuum chamber, had to objective of testing whether the employed components were appropriate for a Low Earth Orbit environment. The executed tests are three, a Hot test, heating the chamber up to +70°C in vacuum, a Cold test, cooling the chamber to −30°C in vacuum, and an Ambient test, both in vacuum and in atmosphere. The navigation algorithm, takes the measures given by the sensors and through these measures and a Kalman filter updates the model of the pose created by the algorithm. These tests have been executed with a robotic arm, a rigid guide, and a Motion Capture System. This thesis has the aim of describing the tests executed on DOCKS and the obtained results, demonstrating that the developed system, is capable of reconstructing the relative pose between chaser and target, in order to obtain the necessary information to conduct the docking between SROC and Space Rider.
Missioni di In Orbit Servicing sono una categoria di missioni, le quali consentono di servire satelliti in orbita, attraverso l’attuazione di operazioni quali trasferimenti nelle orbite operative, ispezione, rifornimento e riparazione. DOCKS è un sistema di docking per piccoli satelliti, sviluppato nell’ambito della missione di SR, realizzata da una collaborazione tra Tyvak, PoliTo, Unipd e Stellar Project, sotto contratto con l’Agenzia Spaziale Europea (ESA). Space Rider Observer Cube (SROC) è un CubeSat 12 U, il cui obiettivo è di eseguire una missione di ispezione di Space Rider (SR), un veicolo in un’orbita terrestre bassa. DOCKS è il meccanismo di aggancio che consente a SROC di rientrare in SR una volta conclusa la sua missione. Il Dipartimento di Ingegneria Industriale (DII) dell’Università degli studi di Padova sta sviluppando il meccanismo di docking, il quale è fatto da due parti. La parte attiva del sistema di docking (DOCKS-A) sarà montata su SROC mentre la parte passiva (DOCKS-B) verrà montata su un dispenser di CubeSat contenuto in SR come payload. DOCKS-A è equipaggiato con 4 tipi di sensori, i quali raccolgono le misure sulla posizione e orientazione di DOCKS-B. I 4 sensori sono una camera di navigazione, 4 sensori di tempo di volo, una matrice e un’unita di misurazione inerziale (IMU), i quali sono usati in varie configurazioni durante le differenti fasi dell’approccio. La fase di Preliminary Design Review prevede l’esecuzione di test su DOCKS. Nel dettaglio, questa tesi descriverà i test in Termo-Vuoto eseguiti a livello di componente e i test sull’algoritmo di navigazione. I test in Termo-Vuoto eseguiti con l’ausilio di una camera termo-vuoto, hanno l’obiettivo di testare se i componenti scelti siano appropriati per un ambiente di orbita terrestre bassa. Sono stati eseguiti tre test, un test Caldo, scaldando la camera a +70°C in vuoto, un test Freddo, raffreddando la camera fino a −30°C in vuoto, e dei test Ambiente, sia in vuoto che in atmosfera. L’algoritmo di navigazione prende le misure date dai sensori, e attraverso queste misure e un filtro di Kalman aggiorna il modello della posa creato dall’algoritmo. Questi test sono stati eseguiti con un braccio robotico, una guida rigida e un Sistema di Cattura del Movimento. Questa tesi ha l’obiettivo di descrivere i test eseguiti su DOCKS e i risultati ottenuti, dimostrando che il sistema sviluppato è capace di ricostruire la posa relativa tra inseguitore e target al fine di ottenere le informazioni necessarie a condurre l’approccio e il docking tra SROC e SR.
Testing of a docking system for small satellites
TUSSARDI, CHIARA
2023/2024
Abstract
In Orbit Servicing Missions are a category of missions which enable the servicing of in orbit satellites, by performing tasks such as orbit relocation, inspection, refuelling and repairing. DOCKS is a docking mechanism for use on small satellites, developed in the framework of SR missions, developed by a collaboration between Tyvak, PoliTo, Unipd and Stellar Project, under contract with the European Space Agency (ESA). Space Rider Observer Cube (SROC) is a 12 U CubeSat, whose target is performing an inspection mission on Space Rider, a space vehicle in a Low Earth Orbit. DOCKS is the docking mechanism which enabled SROC re-entry in SR once, its mission is concluded. The department of Industrial Engineering of the University of Padua is developing the docking mechanism, which is made up of two parts. The active part of the docking system (DOCKS-A) will be mounted on SROC, while the cooperative passive part (DOCKS-B) will be mounted on The CubeSat dispenser contained in SR. DOCKS-A is equipped with a set of 4 sensors, to collect the measures of DOCKS-B position and orientation. The 4 sensors are a NavCam, 4 Time of Flight Distance Sensors, a matrix and an IMU, which are used in various configuration in the different phases of the approach. The Preliminary Design Review has the task of performing tests on DOCKS. In detail, this thesis will describe the Thermal-Vacuum tests performed at a component level and the Navigation Algorithm Tests performed on the navigation algorithm. The Thermal-Vacuum tests performed in a thermal-vacuum chamber, had to objective of testing whether the employed components were appropriate for a Low Earth Orbit environment. The executed tests are three, a Hot test, heating the chamber up to +70°C in vacuum, a Cold test, cooling the chamber to −30°C in vacuum, and an Ambient test, both in vacuum and in atmosphere. The navigation algorithm, takes the measures given by the sensors and through these measures and a Kalman filter updates the model of the pose created by the algorithm. These tests have been executed with a robotic arm, a rigid guide, and a Motion Capture System. This thesis has the aim of describing the tests executed on DOCKS and the obtained results, demonstrating that the developed system, is capable of reconstructing the relative pose between chaser and target, in order to obtain the necessary information to conduct the docking between SROC and Space Rider.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/69393