SOHO is part of the first Cornerstone project in ESA's science
programme, in which the other part is the Cluster mission. Both
are joint ESA/NASA projects in which ESA is the senior partner.
SOHO and Cluster are also contributions to the International
Solar-Terrestrial Physics Programme, to which ESA, NASA and the
space agencies of Japan, Russia, Sweden and Denmark all
contribute satellites monitoring the Sun and solar effects. Of
the spacecraft's 12 sets of instruments, nine come from
multinational teams led by European scientists, and three from
US-led teams. More than 1500 scientists from around the world
have been involved with the SOHO programme, analysing and
interpreting SOHO data for their research projects. SOHO was
built for ESA by industrial companies in 14 European countries,
led by Matra Marconi (now called ASTRIUM). The service module,
with solar panels, thrusters, attitude control systems,
communications and housekeeping functions, was prepared in
Toulouse, France. The payload module carrying t