MicroLabSat is a 50(kg) class micro satellite that was launched on December I4, 2002. MicroLabSat switches attitude control modes according to the operation mode. In the nominal operation mode, spin-stabilized control is used. In the mission mode, three axis control is used. MicroLabSat carries only simple low cost sensors for attitude determination. This paper describes design and development of the MicroLabSat attitude control system.

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The CCD Earth Sensor (CCDESA) is an attitude sensor that estimates three-axis attitude angles using the Earth’s images. Current Earth sensors detect infrared rays radiated by CO₂, however, the CCDESA detects the Earth by acquiring visible rays with a Charge Coupled Device (CCD). This CCDESA is a mission sensor of μ-LabSat which was launched by H-IIA as a piggyback satellite in December 2002. This paper discusses the CCDESA and the results of the on-orbit experiments.

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“μ-LabSat”, a micro-piggyback satellite, was launched by an H-IIA rocket on 14 December 2002. One of its missions was to release truncated cone-shaped targets with representative dimensions of approximately 10 cm and evaluate the use of machine vision to estimate their position and attitude relative to the satellite. As a follow-on mission using the same camera, a three-axis attitude control moon-tracking maneuver was planned with the following steps: (1) recognize the moon in captured images and track it continuously, (2) calculate the median point of the moon, (3) control the satellite's attitude to move the moon's position in the image to the near the image center, (4) maintain the moon's position near the center of the image. μ-LabSat is a bias-momentum micro-satellite with two wheels, a configuration that is not normally capable of three-axis attitude maneuvers. This paper describes an algorithm “Sliding Mode Controller using Rodriguez parameter” that has been developed to enable such maneuvers, and presents the results of its evaluation by numerical simulation and the on-orbit moon tracking experiment.

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Micro LabSat is a 50kg-class microsatellite developed by JAXA (formerly NASDA). It was launched on December 14, 2002 by an H-IIA launch vehicle. The Attitude Control Subsystem (ACS) must provide sufficient attitude control capabilities required to carry out several technology demonstration experiments, such as on-orbit inspection experiments using onboard CMOS cameras, CCD Earth Sensor Assembly (CCDESA) experiments, and so on. Since the launch, the ACS has functioned normally. This paper describes the on-orbit operation and performance of the Micro LabSat ACS.

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