The idea for the Cluster project dates back to a February 1983 meeting of ESA (European Space Agency) scientists and engineers. The mission was selected in 1998 alongside the Soho programme, as part of ESA’s “Horizon 2000” project.

More than 250 researchers from 70 laboratories in 17 countries participated in the project. Cluster and Soho contributed to the International Solar Terrestrial Programme (ISTP) to study the Sun and its interaction with Earth.

Simultaneous observations by the 4 Cluster satellites, operating in a tetrahedral formation, resolved these ambiguities.

In 1996, the 4 Cluster 1 satellites were destroyed during the failed inaugural launch of Ariane 5. Nearly 10 years of work was lost in a single minute.

In 1997, ESA, in agreement with the international scientific community, decided to resurrect the project. The Cluster 2 satellites and instruments, successfully launched during the summer of 2000, are identical to those of the initial mission.