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Project Irazú was an innovative space mission that aimed to propel the advancement of the aerospace sector in Costa Rica, by developing a ground to space communication solution for daily monitoring of carbon fixation in forests and tree plantations. Irazú is Central America's first satellite mission and is a joint endeavor between the Central American Association of Aeronautics and Space and the Costa Rica Institute of Technology, along with national and international partners. The 1U CubeSat developed in this project was deployed from the International Space Station on May 2018, commencing straightaway operations. The scientific mission demonstrated a practical novel solution to monitor daily tree growth by using wireless electronic sensors and a store and forward satellite link. This article presents an overview of the project, along with the mission architecture, summary of the Assembly, Integration and Testing (AI&T) and operations phases, and results from the scientific mission, including the sensor's performance and measurements of the daily estimated tree diameter during six months. The impacts that the project had on an emerging space nation such as Costa Rica is included as well. [ABSTRACT FROM AUTHOR]

This paper focuses on the attitude control problem of small agile satellites using single-gimbal control moment gyros (CMG) and magnetic torquers (MTQ). CMGs are regarded as effective torque generators for agile satellites because of their torque amplification capability. However, they are vulnerable to failure due to their complex inner mechanism. In this paper, different failure cases of CMGs are analyzed. A flexible failure-tolerant control strategy is developed by automatically redistributing the required control torque among the operating CMGs and MTQs, with a variable limiter to accommodate the actuator dynamics changes introduced by CMG failures. The performances of maneuvers about different directions under different failure cases are also discussed and examined. Numerical simulations demonstrate that the proposed strategy maintains certain agility in the cases of one or two CMGs failing. Moreover, a survival strategy with only one CMG left is also verified. Both sun-pointing stabilization and earth-pointing stabilization can be achieved in this case, which fulfill some basic mission requirements. [ABSTRACT FROM AUTHOR]

Laboratory for Space Systems (LSS), Tokyo Institute of Technology (Tokyo Tech) conducted three-dimensional microgravity environment experiments about a docking mechanism for mothership-daughtership (MS-DS) nano-satellite using the facility of Japan Micro Gravity Center (JAMIC) with Hokkaido Institute of Technology (HIT). LSS has studied and developed a docking mechanism for MS-DS nano-satellite system in final rendezvous approach and docking phase since 2000. Consideration of the docking mechanism is to mate a nano-satellite stably while remaining control error of relative velocity and attitude because it is difficult for nano-satellite to have complicated attitude control and mating systems. Objective of the experiments is to verify fundamental grasping function based on our proposed docking methodology. The proposed docking sequence is divided between approach/grasping phase and guiding phase. In the approach/grasping phase, the docking mechanism grasps the nano-satellite even though the nano-satellite has relative position and attitude control errors as well as relative velocity in a docking space. In the guiding function, the docking mechanism guides the nano-satellite to a docking port while adjusting its attitude in order to transfer electrical power and fuel to the nano-satellite. In the paper, we describe the experimental system including the docking mechanism, control system, the daughtership system and the release mechanism, and describe results of microgravity experiments in JAMIC. [ABSTRACT FROM AUTHOR]

Deals with a study which described the concept of reconfigurable brachiating space robot (RBR) and its ground testbed for on-orbit experiments in the International Space Station. Objectives of the RBR research project; Physical features of the robot; Recommendations for operation.

To suppress the low frequency vibration of Large Space Structures, the possibility of using a proof-mass based actuator is discussed. In order to avoid instabilities caused by the effect of the actuator's own natural frequency on the low frequency components of the structural vibration, it is proposed that the only control force be the electromagnetic force generated by the actuator and that there be no mechanical spring between the moving and the fixed parts of the actuator. In this configuration, it is easy for the moving mass of the actuator to exceed the stroke limit, so the actuator must be controlled to avoid these limits. Using the proposed actuator, three kinds of intelligent control methods are considered in order to achieve reliable control of the low frequency vibrations: fuzzy control, dithered fuzzy control, and rule based crisp control. Simulation results show the effectiveness of the proposed control algorithms. [ABSTRACT FROM PUBLISHER]