CLUSTER summary
Description: ESA's Cluster II mission consists of four identical spacecraft flying in formation high above the Earth's poles. It is a replacement of the original Cluster mission which was lost in a launch failure during the maiden flight of the Ariane 5 rocket on 4 June 1996. The new Cluster mission was launched in 2000. Due to its success, the original two-year mission has been extended twice, first through 2005 and then through 2009.Objectives: Cluster is part of an international
collaboration
to investigate the physical connection between the Sun and Earth.
Flying
in a tetrahedral (triangular pyramid) formation, the four spacecraft
will
collect the most detailed data yet on small-scale changes in near-Earth
space and the interaction between the charged particles of the solar
wind
and Earth's atmosphere. This will enable scientists to build a
three-dimensional
model of the magnetosphere and to better understand the processes
taking
place inside it.
Scientific results: An
enormous lot! See the list of Cluster
top stories at ESA.
How the mission was named: The name Cluster was chosen because of the way the four spacecraft will fly in a group around the Earth. When studies demonstrated that it would be possible to reuse some parts and to fly four spacecraft which were almost identical to those which were lost, the replacement mission was named Cluster II
Industrial involvement: Prime contractor for Cluster was Dornier Satellitensysteme GmbH, Friedrichshafen, Germany, the leader of an industrial consortium involving 35 major contractors from all of the ESA member countries and the United States
Launch date: July 16 and August 9 2000
Launcher: Two Russian Soyuz launchers with a Fregat upper stage, provided by the Russian-French Starsem consortium
Satellite names: The satellites have been named Salsa, Samba, Rumba and Tango
Satellite launch mass: Approximately 1 200 kg each (fully fuelled) including 71 kg of scientific payload
Dimensions: Main spacecraft diameter 2.9 m, height 1.3 m. Each also carries two antenna booms, two 5 m experiment booms and four 50 m experiment wire booms
Payload: Each spacecraft carries an identical set of 11 instruments to investigate charged particles, electrical and magnetic fields i.e. space weather. These were built by European and American instrument teams led by Principal Investigators
Orbit: Elliptical polar orbit, 19 000 to 119 000 km, 57 hour period.
Spacecraft operations centre: European Space Operations Centre (ESOC), Germany
Ground station: Villafranca, Spain
Science operations centre: Joint Science Operations Centre at Rutherford Appleton Laboratory, Didcot, UK
Foreseen operational duration: 27 months
Cost: 315 million Euros at 1999 economic conditions (including manufacturing, launch and operations of the Cluster II spacecraft, and 40% of the funding for the payload)
Spacecraft vital statistics
| Diameter: | 2.9 m |
| Height: | 1.3 m |
| Mass: | 1 200 kg |
| (of which) Propellant: | 650 kg |
| (of which) Scientific payload: | 71 kg |
| Solar array power: | 224 W |
| Spin rate: | 15 rpm |
| Operational lifetime: | 2 years |
Soyuz launcher facts
| Lift off weight: | 304 tonnes |
| (of which) Propellant weight: | 279.5 tonnes |
| Height: | 43.5 m |
| Maximum diameter: | 10.3 m |
| Thrust (in vacuum) | |
| - first stage: | 4 964 kN |
| - second stage: | 997 kN |
| - third stage: | 298 kN |
| - fourth stage (Fregat): | 19.6 kN |
| Payload capability (to 400 km): | up to 6 tonnes |
Launcher facts: the Fregat upper stage
| Diameter: | 3.35 m |
| Height: | 1.5 m |
| Lift off weight: | 6 415 kg |
| (of which) Propellant weight: | 5 350 kg |
| Propellant | |
| - fuel: | Unsymmetrical dimethyl-hydrazine (UDMH) |
| - oxidizer: | Nitrogen tetroxide |
| Main engine thrust: | 19 620 N |
last modified on Tuesday, 23-May-2006 09:42:44 CEST