The International Heliospheric Study Author:M. A. Shea, E. J. Smith, M.A. Shea, E.J. Smith The International Heliospheric Study is a program sponsored by COSPAR that exploits the unique scientific opportunities presented by the continuing operation of the four Pioneer and Voyager spacecraft which are all in or beyond the outer solar system. The heliosphere is the region of space surrounding the sun which is dominated by the solar wind... more » and from which the local interstellar plasma and magnetic field are excluded. The multispacecraft studies which form the basis of the IHS encompass the structure and dynamics of the solar wind and its interaction with the interstellar medium including those components, neutral gas and galactic cosmic rays, which are able to penetrate into the heliosphere.« less