Orbital Test Satellite (OTS) - artist's impression

In-orbit configuration of ESA's OTS-2 telecom satellite. Launched 12 May 1978, the highly successful OTS-2 was not retired from geostationary orbit until January 1991. ESA's Orbital Test Satellite (OTS) project demonstrated technologies and techniques for a new generation of telecommunications satellites, leading directly to the ECS and Marecs designs.