The Cluster mission is comprised of four identical spacecraft launched into large, elliptical polar orbits around the Earth. After transfer to their operational orbits they will fly in formation to allow scientists to measure subtle changes in the interaction between the Earth and the Sun. The four spacecraft will look at how particles from the Sun interact with the Earth's magnetic field. Cluster will observe the magnetic and electrical interactions between the Earth and the Sun, by making direct measurements of the fields and particles trapped in the Earth's magnetic field. For the first time, small-scale fluctuations in interplanetary space will be measured between each spacecraft as they orbit the Earth.
For more information see the Cluster Home Page
Cluster ASPOC Brief DescriptionActive Spacecraft Potential Control tries to "Earth" the spacecraft by getting rid of excessive positive surface charge by emitting indium ions.
Cluster EDI Brief DescriptionElectron Drift Instrument employs the latest technology to "fire" a beam of electrons in a circular path for many tens of kilometers around the spacecraft. A receiver on the other side of the spacecraft will pick up the returning beam of electrons. The strength of the plasma electric field will alter this aim point.
Cluster FGM Brief DescriptionFluxgate Magnetomoter
Cluster CIS Brief DescriptionCluster Ion Spectrometre analyses the composition and dynamics of the particles surrounding the spacecraft, concentrating on the slowest moving ions in space.
Cluster PEACE Brief DescriptionPlasma Electron And Current Analyzer looks at the distribution, direction and flow plus energy distribution of electrons from low to medium energies.
Cluster RAPID Brief DescriptionResearch with Adaptive Particle Imaging Detectors is essentially a "pin-hole camera" into which electrons and ions with the highest energies pass.
See also RAPID WWW page
Cluster STAFF Brief DescriptionSpatio Temporal Analysis Field Fluctuation looks at the way magnetic fields change with time.
Cluster EFW Brief DescriptionElectric Field and Wave Experiment observes the way in which the elctric field around the spacecraft changes with time.
Cluster WHISPER Brief DescriptionWave of HIgh frequency and Sounder for Probing of Electron density by Relaxation actively measures the density of the hot, electrically-conducting "plasma" which emenates from the Sun.
Cluster WBD Brief DescriptionWide Band Data makes high time/frequency resolution measurements of the electric field, up to several hundred kilohertz. See also WBD page.
Cluster WEC/DWP Brief DescriptionWave Consortium (STAFF-EFW-WHISPER-WBD) Digital Wave Processor acts as the control and computing brain for the wave consortium experiments (STAFF-EFW-WHISPER-WBD).