A tethered space robot, which is connected to a mother spacecraft through a peace of tether, is a new space

The Space Tethered Autonomous Robotic Satellite (STARS) was developed in Kagawa University and launched by the H-IIA rocket by the Japan Aerospace Exploration Agency (JAXA) on 23 January, 2009. The primary objective of STARS is technical verification of a tethered space robot, which is connected to a mother spacecraft through a tether, proposed in 1995. Main characteristics of STARS are: (i) it is mother-daughter satellite; (ii) it becomes a tethered system on orbit; (iii) the daughter satellite is a tethered space robot. STARS consists of two satellites connected by a tether. One is a mother satellite (a mother spacecraft), which deploys and retrieves a tether connected to the other satellite. The other is a daughter satellite (a tethered space robot). The mother satellite has a tether deployment system. During tether deployment, the attitude of the daughter satellite is controlled by its own arm link motion, and a camera mounted on the daughter satellite takes a photograph of the mother satellite. It is important to design launch lock for STARS, since it has many actuation parts and it is two satellites system. 978-1-4244-4602-5/09/$25.00 ©2009 IEEE

A space robot attached to the far end of a tether deployed from a spacecraft is considered. Such a robot can be made to translate freely in space without the need of jet thrust, using tether tension. The tethered robot can be applied to perform a variety of tasks such as grappling a remote object, transporting supplies, servicing a satellite, and so on. A casting strategy is described that is accomplished by means of a manipulator mounted on the spacecraft. The tether is attached to the endpoint of this manipulator. The spacecraft-mounted manipulator generates the necessary initial momentum for the tethered robot and adjusts its trajectory by controlling tether tension. The desired nal state of the tethered robot includes accurate positioning at the destination point with zero momenta. To achieve such a state, a cooperative control scheme for translation and link motion of the tethered robot is proposed. The effectiveness of the proposed control approach is con rmed by computer simulations.

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