Nano-and pico-satellites are currently used as low cost in-orbit-demonstrators of new technologies or for the university research. These satellites are launched to the low Earth orbits and radio commanded from the ground control stations. Most of them are equipped with narrow band transceivers working in UHF radio amateur frequency band, reaching only low data transmission rates. Low Earth orbits also limits the number and duration of satellite passing in the range of ground control station. One ground control station has approximately six satellite passes per day, each with duration only in few minutes. This strictly limits the amount of transmitted data between satellite and ground control station. In this paper the software controlled and assisted radio commanding of VZLUSAT-1 nanosatellite during the QB50 scientific mission is described. Two basic modes of satellite radio commanding are described with the aim to increase data throughput during commanding. Software controlled autonomous and software assisted semi-autonomous modes allow effective commanding of satellite while keeping the attention of satellite operator to the satellite condition and keeping the full control over the radio transmission as radio amateur regulation requires. Also the critical operational limits of satellite electronics faces to cosmic vacuum and radiation environment have to be continuously monitored for safety satellite operation.

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One of the main goals of the PilsenCUBE-II picosatellite project is to offer on board payload space for the student's experiments for the students from the various secondary schools of the western Bohemia. The students experiments have to be simple enough in scope of skills and abilities of the secondary schools students but should provide interesting results for satellite project. There is 6 student's experiments in the second round of competition. This experiments will be integrated into satellite as a parts of the measurement board (MES). The measurement board will provide the interface between these student's experiments (STE) and On-Board Computer (OBC) that is controlling the functions of the satellite and providing the communication with ground station.

Keywords -forward error correction code; cross parity check code, multidimensional parity check code; product code; iterative decoding; CubeSatI.[ 177 ] ISBN 978-80-261-0813-9,