Main mission of STARS-I (Space Tethered Autonomous Robotic Satellite I) is to verify technology for Tethered Space Robot (TSR). STARS-I contains of two subsatellites called daughter satellite and Mother Satellite, respectively. Those satellites are connected through a peace of tether, and tether is deployed for 1m – 10m. The minimum success level is set as:
• Deployment and retrieval of daughter satellite from mother satellite
• Attitude control of daughter satellite by arm motion
Mother satellite has a function to deploy and retrieve of tether, and daughter satellite has Tethered Space Robot function, that is attitude control by its own link motion under tether tension. Experimental mission is performed as:
• Mother satellite gives an initial velocity to daughter satellite
• Daughter satellite is deployed and retrieved under tether control by mother satellite
• Daughter satellite docks with mother satellite.
Daughter satellite and mother satellite have following subsystems respectively.
• Electrical power subsystem
• Data handling subsystem
• Camera subsystem
• Telecommunication subsystem
• Structure subsystem,
Daughter and mother satellites have specific subsystems “attitude subsystem” and “deployment subsystem”, respectively.
Functions of electrical subsystem are: cattery charging control, delivering electrical power to other subsystems through data handling subsystem, and monitoring electrical current consumption and temperature of electrical circuit board. Charging control IC controls charging Li-Ion battery. Regulator generates voltages 4.2V, 5.0V, and 6.0V to deliver to subsystems. Ammeters and voltmeter monitor at respective points, and thermo sensor monitors electrical circuit board temperature.
Data handling subsystem operates data among other subsystems, and delivers electrical power from electrical power subsystem to other subsystems. It controls sequences and monitors condition of the satellite. Data of each subsystem is kept in the data handling subsystem, and sent to the ground station through telecommunication subsystem. Experimental command, reset command of electrical power subsystem, taking picture command, etc, from the ground station through telecommunication subsystem are delivered to each subsystem by data handling subsystem.
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