Applying a simple contol law to deploy space tether on a micro Tethered satellite

A micro tethered satellite QTEX (KYUshu university Tethered satellite EXperiments) is under development in Kyushu University. QTEX project is a students-led project and it aims for low-cost and short term development, and the satellite will be ready for launch by 2006. The dimensions of the satellite are approximately 50*50*50 [cm³], and it weighs less than 50 kg. As for the configuration, the mother satellite and the daughter satellite are almost the same except for the tether reel mechanism on the mother. The primary mission of the QTEX is to prove a new tether deployment method : QTEX aims for 2 km long tether deployment. In this method, tether deployment will be carried out with open-loop control, and the satellite does not need to measure the tether length and its tension. The tether is deployed according to the motor rotation profiles which are calculated beforehand. Then the tether deployment mechanism is simplified and downsized, and finally the satellite becomes small enough to be launch in a piggyback fashion with the Japanese launch vehicle H-IIA. In this paper, first, the tether dynamics is formulated, then, the tether deployment profiles are proposed and some numerical simulations are performed, finally the feasibility of QTEX missions is analyzed.