ESA News
http://www.esa.int

14 July 2005

Cluster spacecraft reach greatest separation at fifth anniversary

The four spacecraft of ESA's Cluster fleet have reached their greatest
distance from each other in the course of their mission to study Earth's
magnetosphere in three dimensions.

This operation, marking the fifth anniversary of Cluster in space,
transforms Cluster in the first 'multi-scale' mission ever.

In one of the most complex manoeuvres ever conducted by ESA spacecraft,
three of the spacecraft were separated to 10 000 kilometres from each
other, with the fourth spacecraft at 1000 kilometres from the third one.

This new fleet formation for Cluster was achieved in two months of
operations. The repositioning of the satellites was started by mission
controllers at ESA's European Space Operations Centre (ESOC), in
Darmstadt, Germany, on 26 May, and was run until 14 July.

During the course of the mission, the distance between the Cluster
satellites had already changed five times, in a range between 100 and
5000 kilometres. Varying the size -- but not the shape -- of the Cluster
'constellation' had allowed Cluster to examine Earth's magnetosphere at
different scales.

But now this new 'asymmetric' flying formation is allowing the Cluster
spacecraft to make measurements of medium- and large-scale phenomena
simultaneously, transforming Cluster in the first ever 'multi-scale'
mission.

With this, it is possible to study at the same time the link between
small-scale kinetic processes of the plasma around Earth and the
large-scale morphology of the magnetosphere.

The knowledge gained by Cluster about the magnetosphere -- the natural
magnetic shield that surrounds and protects our planet -- has already
helped advance our understanding of how the solar wind affects Earth's
natural space environment.

This is also important in our daily life as, for instance, intense solar
activity can disrupt terrestrial communication networks, power grids and
data lines.

For more information:

Hermann Opgenoorth, ESA Cluster Mission Manager
E-mail: hermann.opgenoorth @ esa.int

Philippe Escoubet, ESA Cluster Project Scientist
E-mail: Philippe.Escoubet @ esa.int

More about...

* Double Star overview
http://www.esa.int/esaSC/120381_index_0_m.html
* Cluster overview
http://www.esa.int/esaSC/120383_index_0_m.html

Related articles

* Second Double Star satellite successfully launched
http://www.esa.int/esaSC/SEMIQMV4QWD_exploring_0.html
* How the Sun affects us on Earth
http://www.esa.int/esaSC/SEML7BS1VED_foryou_0.html
* Surfing and diving in the Earth's magnetosphere, Cluster celebrates
one year of science excellence in orbit
http://www.esa.int/esaCP/ESAN3D0VMOC_index_0.html
* Cluster's new view of near-Earth space
http://www.esa.int/esaCP/ESA6VTTM5JC_index_0.html
* Solar storm blasts Cluster
http://www.esa.int/esaCP/ESAB7E8VTTC_index_0.html
* ESA's Cluster sees 'squashed' magnetosphere
http://www.esa.int/esaSC/SEMGZ8WLDMD_exploring_0.html

Related links

* More on Cluster operations
http://www.esa.int/spacecraftops/index.html

IMAGE CAPTION:
[http://www.esa.int/esaCP/SEM0UH6DIAE_index_1.html]
An artist's impression of the Cluster quartet. Credits: ESA