The challenge of long-duration human space missions: principles of LSS integrity

The presence of human beings in space is stimulated not only by romantic impulse to "boldly go where no one has gone before", but has purely pragmatic reasons. Effective solution of commonly known problems of space exploration and mastering is not possible without almost direct human participation. Economical and the Earth's safety motives of long-duration and long-distance human flights are briefly discussed in the paper. Effectiveness presumes optimization of LSS features at the level of the whole mission. It means that integral criterion of mission successfulness has to include parameters of LSS itself. The problems and objectives of reliable and effective LSS design are considered. Aspects of long-term LSS design closely connected with space mission scenario are discussed.