Modes and More; Finding the Right Attitude for TET-1

Abstract

TET-1 (a German abbreviation meaning technology experiment carrier) is a small German satellite bringing eleven technical experiments into space. It was built by Kayser-Threde (Munich) and Astro- und Feinwerktechnik Berlin, and will be operated by GSOC for at least one year. Its launch will be piggy-back with Kanopus-Vulkan 1, an Earth observation mini-satellite of the Russian Space Agency, on a Soyuz FG / Fregat rocket from Baikonur/Kazakhstan, which dependency caused a delay of more than a year. The new technologies to be verified cover a wide field – ranging from an infrared camera to e.g. a new type of GPS receiver or solar cells -- requiring a large number of operational modes and a variety of pointing requirements. TET-1 has no orbit control and the finally achieved injection dictates attitude operations to a large extent; several modes require a specific attitude to reach the desired accuracy. Another challenge to the attitude control system is the high degree of autonomy required. TET-1 is monitored in two consecutive orbits every twelve hours, but uplink capability is limited to only once per day.