International Terrestrial Solar Physics Project

Project Description
Since the 1980s, the collaborative efforts by NASA, the European Space Agency (ESA), and the Institute of Space and Astronuatical Science (ISAS) of Japan have led to the conception of the International Solar-Terrestrial Physics Science Initiative consisting of a set of solar-terrestrial missions to be carred out during the 1990s and into the next century.

http://www-istp.gsfc.nasa.gov/istp/misc/istp_project.html