YES2 DHS: a space tether control subsystem

This paper describes the architecture and laboratory prototype implementation of the data handling subsystem (DHS) contributed by Team Canada to the Young Engineers´ Satellite (YES2) project YES2 is a space-tether initiative of the European space agency uniting thirty universities in Europe, Canada, Asia, and Australia. The purpose of the DHS is to control a 35 km swinging tether for insertion of a low-mass payload into the Earth´ s atmosphere from a low-orbiting spacecraft such as the International Space Station. Single event effects, absence of convective cooling, and tether length estimation are the primary design challenges. As a consequence, key software and hardware design features include radiation mitigation, power minimization, thermal mitigation, pulse detection and emphasis on discrete components. The DHS has recently undergone interface testing with teams from Spain, Italy, and Germany at the first YES2 test readiness review at ESTEC with launch scheduled on a Russian carrier for 2005.