Cluster-II: Scientific objectives and data dissemination

The Cluster-II mission is designed to study the near-Earth space environmen t in three dimensions. This will be the first scientific mission with four identical spacecraft flying together in the Earth's environment. The relati ve distance between the four spacecraft will vary between 200 and 18 000 km , according to the scientific region of interest. Cluster-II and the Solar and Heliospheric Observatory (SOHO) together make up the Solar Terrestrial Science Programme, the first 'Cornerstone' of ESA's Horizons 2000 long-term science plan.