DLR-Tubsat (Deutsche Forschungsanstalt für Luft- und Raumfahrt - Technische Universität Berlin Satellit) is a joint project of the DLR and the Institute of Aeronautics and Astronautics at the Technical University of Berlin. Based on the experience gained with TUBSAT-A and TUBSAT-B an attitude control unit of minimal dimensions has been developed for the DLR-TUBSAT microsatellite.
The satellite has a mass of approximately 45 kg and a cubic shape of 32 cm length. It is mainly used for high resolution Earth observation tasks. This is done in a live TV mode with a three head camera system with different focal lengths, resulting in a resolution of 370 meter down to six meter per pixel. The pictures can be received with a standard satellite dish with a minimum of three meter diameter. The mission scenario implies, that the users transmits the coordinates of a point on the earth and the satellite computes the needed attitude control actions to track this point during the crossing.
The S-Band antenna (white cylinder on the right) has the same direction as the optics. The antenna is a helix antenna and has an opening of 70 degrees. To receive the signal of the satellite the user will have to be within a 70 degree cone around the optical axis. This means one can only make pictures of an area within aproximatly 1000 km range of your receiving ground station.
The control is done by transmitting ground coordinates to the satellite. Attitude control is done with three reaction wheels and three fibre optic laser gyros. After the contact is over, the satellite disables all its systems but the TTC and the OBDH and goes into what was called "barbeque mode": It is tumbeling freely without attitude control so that it is warmed up by the sun from all sides.
|Type / Application:||Earth observation|
|Power:||Solar cells, batteries|
|Orbit:||716 km × 737 km, 98.36°|
|DLR-Tubsat (Tubsat 5)||1999-029B||26.05.1999||Sr FLP||PSLV-G (2)||with IRS P4, Kitsat 3|