Illustration of the Solar and Heliospheric Observatory (SOHO), which was launched on 2 December 1995 by an Atlas rocket. SOHO makes continuous observations of the solar surface, the solar corona and solar wind. It is equipped with 11 instruments and is placed between the Earth and the Sun at a distance of 1.5 million km from Earth. The SOHO spacecraft represents the contribution of the European Space Agency (ESA) to the International Solar Terrestrial Physics (ISTP) program. ISTP involves a total of 12 satellites provided by Europe, the United States, the CIS (the former USSR) and Japan.