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 the scientific instruments was assembled in Portsmouth, United Kingdom, and mated with the service module in Toulouse, France. NASA launched SOHO and is responsible for tracking, telemetry reception and commanding.