Summary
This overview describes an international scientific cooperation between Brazil, USA and Japan, for an integrated research program developed in south of Brazil for observations of solar-terrestrial interactions and geospace. Space weather variability may damage the satellites in space and also harm systems on the Earths surface like those of electric power transmission lines, telecommunications and GPS based services. Space weather is nowadays in a similar position to meteorology a century ago. We need to understand the physics and develop capacity for space weather forecast in order to reduce the damages to present day technological systems. Observations done by several space missions are important for the understanding of these phenomena, however it is also important to have ground observations, to complement those from space. In this sense, the international scientific cooperation being conducted in Brazil since 2001 is very important, as it will bring development in the strategic areas of national and international interest. A multidirectional telescope for detection of high-energy cosmic rays muons was installed in 2001, through our international cooperation and is operational since then at the Southern Space Observatory SSO/CRS/INPE - MCT, So Martinho da Serra, RS, Brazil, (29S, 53W) whose capacity and sensitivity were upgraded in 2005. The observations conducted by this telescope are used for forecasting the arrival of the geomagnetic storm drivers in the near-earth geospace. Solar mass ejections traveling in the interplanetary space cause reduction in cosmic ray counts at the earths surface by one to ten percent, and can be detected almost ten hours before their arrival at earth if the global network of muon detectors are deployed all over the world by the scheme developed at the Shinshu University, Japan. The Brazilian detector telescope at SSO, So Martinho da Serra, is a part of this muon detector network collaboration, consisting of 9 institutes from 7 countries.