* Astronomy

Blobrana · L

RE: Cluster satellites

Blobrana · L

Rejigging the Cluster quartet

Aiming to study Earth's 'bow shock' in the solar wind, the constellation of Cluster satellites is being rejigged to bring two of the four to within almost touching distance.
ESA's Cluster quartet, in orbit since 2000, is studying the detailed structures of Earth's magnetosphere - our protective magnetic bubble - and its environment in 3D.
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Cluster finds source of aurora energy boost

A new study based on data from ESA's Cluster mission has revealed the importance of bursty bulk flows (BBFs) - fast streams of plasma that are launched towards Earth during the magnetic substorms that give rise to bright aurorae. By modelling these fast plasma streams using a kinetic approach, scientists have discovered that earlier studies based on magnetohydrodynamics tended to underestimate their role in the energy transfer during magnetic substorms. The new, more accurate description suggests that BBFs can carry up to one third of the total energy transferred during a substorm; in such cases, BBFs represent a major contributor to the brightening of aurorae.
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Cluster Mission Indicates Turbulent Eddies May Warm the Solar Wind

The sun ejects a continuous flow of electrically charged particles and magnetic fields in the form of the solar wind -- and this wind is hotter than it should be. A new study of data obtained by European Space Agency's Cluster spacecraft may help explain the mystery.
The solar wind is made of an electrically-charged gas called plasma. One theory about the wind's puzzling high temperatures is that irregularities in the flow of charged particles and magnetic fields in the plasma create turbulence, which, in turn, dissipates and adds heat to its surroundings. Using two separate sets of data sent back by Cluster, an international team of scientists has probed the spatial characteristics of this turbulence in more detail and at smaller scales than ever before. They saw evidence that the turbulence evolved to form very small "current sheets" -- thin sheets of electrical current that separate regions of rotated magnetic field.
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Blobrana · L

Cluster is a space mission of the European Space Agency, with NASA participation, to study the Earth's magnetosphere over the course of an entire solar cycle. The mission is composed of four identical spacecraft flying in a tetrahedral formation. The four Cluster spacecraft were successfully launched by pair in July and August 2000 onboard two Soyuz-Fregat rockets from Baikonur.
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Blobrana · L

On 16 July 2000, the first pair of the ESA Cluster flotilla blasted off aboard a Russian Soyuz rocket from Baikonur, Kazakhstan.
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Blobrana · L

Cluster is a space mission of the European Space Agency, with NASA participation, to study the Earth's magnetosphere over the course of an entire solar cycle. The mission is composed of four identical spacecraft flying in a tetrahedral formation. The four Cluster spacecraft were successfully launched by pair in July and August 2000 onboard two Soyuz-Fregat rockets from Baikonur.
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Blobrana · L

'Dirty hack' restores Cluster mission from near loss

Using ingenuity and an unorthodox 'dirty hack', ESA has recovered the four-satellite Cluster mission from near loss. The drama began in March, when a crucial science package stopped responding to commands - one of a mission controller's worst fears.
Since a pair of spectacular dual launches in 2000, the four Cluster satellites have been orbiting Earth in tightly controlled formation. Each of the 550 kg satellites carries an identical payload to investigate Earth's space environment and its interaction with the solar wind - the stream of charged particles pouring out from the Sun.
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Blobrana · L

Cluster encounters a natural particle accelerator

ESA's Cluster satellites have flown through a natural particle accelerator just above Earth's atmosphere. The data they collected are unlocking how most of the dramatic displays of the northern and southern lights are generated.
Two of Cluster's four satellites found themselves in a natural particle accelerator above the northern hemisphere on 5 June 2009. The first to cross was satellite C3 at an altitude of 6400 km, followed five minutes later by C1 at 9000 km.
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Blobrana · L

Cluster mission