SOHO was built for ESA by industrial companies in 14 European countries, led by Matra Marconi. 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, UK, and mated with the service module in Toulouse, France.
The total mass of the spacecraft at launch was 1850 kg. Its overall length along the sun-pointing axis is 4.3 metres, and the span of the extended solar panels is 9.5 metres.