In Meteorology the effect of the Sun is an undisputed a-priori input to any kind of predictions of atmospheric weather. In the upper atmosphere and even more so in the near space environment of our planet, the recognition of the sun as a very efficient driver of disturbances and a highly variable source of magnetic fields and plasmas has not been so unproblematic. It took over 50 years of scientific efforts, heavily supported by space missions, to establish the present view, where a highly variable central star plays a key role in the long and short term dynamics of planetary atmospheres and near-space environments, such as ionospheres and magnetospheres.

But even though our understanding of the physical processes in space plasmas has drastically improved during recent coordinated space programs like e.g. the ISTP (International Solar Terrestrial Physics Programme), we still lack the final proof of whether we fully understand the relative importance of the various identified interactions, that is the so-called "geo-efficiency" of several kinds of Solar variability. Such a proof can only be provided by the achievement of reasonably accurate predictions of consequences in the near-Earth space, as caused by Solar events.

Recognizing the maturity of the field of space plasma physics and also the need to predict variability of the terrestrial and interplanetary space environment for the benefit of a future expansion of human presence in space, the major space agencies of the world have started a new science initiative to address the variability of the sun as a Star and the predictable effects of such variability on the environment and technological products of mankind.

We will present the mission and objectives of this new initiative, called International Living With a Star ((ILWS) and review the practical means to address the posed problem with the help of coordinated international space missions, global ground-based instrument networks and dedicated theory and model activities.