Cluster-II is a cooperative mission between NASA and ESA. On 3 April 1997 ESA's Science Programme Committee approved the reflight of the full mission by mid-2000. Cluster II will comprise the Phoenix spacecraft (built from the original flight spares) and three identical new satellites to be built bya European industrial consortium led by Daimler Benz Aerospace (Dornier). The Cluster II mission is an in-situ investigation of the Earth's magnetosphere using
four identical spacecraft simultaneously. It will permit the accurate determination of three-dimensional and time-varying phenomena and will make it possible to distinguish between spatial and temporal variations. The satellites will be launched in two pairs by two Soyuz launchers (procured through the Starsem consortium) in mid-2000 from the Baikonur cosmodrome in Kazakhstan.

As planned, the four spacecraft will carry out three-dimensional measurements in the Earth's magnetosphere, covering both large-scale and small-scale phenomena in the sunward and tail regions. Once Cluster II has joined Soho in orbit, the original aims of the combined Solar-Terrestrial Science Programme, STSP should at last be fulfilled.

Eventually the Cluster II and SOHO measurements will also be coordinated with an international fleet of spacecraft, through the IACG (Inter-Agency Consultative Group) to form a unique set of data on the interaction between the Sun and the Earth.

Salient Features:

Project Start: 2nd quarter 1995
Spacecraft Weight Dry: 525 kg
Planned Lifetime: 2 years
Orbit: apogee of 19.6 Earth radii and a perigee of 4 Earth radii
Launch: June-July 2000

Instrument Complement:

STAFF, the Spatio-Temporal Analysis of Field Fluctuations experiment (PI: N. Cornilleau-Wehrlin)
EFW, the Electrical Field and Wave experiment (PI: G. Gustaffson)
DWP, the Digital Wave-Processing experiment (PI: H. Alleyne)
WHISPER, the Waves of High Frequency and Sounder for Probing of
Density by Relaxation experiment (PI: P.M. Decreau).
WBD, the Wideband Data instrument (PI:D.A. Gurnett)
FGM, the Fluxgate Magnetometer (PI: A.Balogh)
EDI, the Electron Drift Instrument (PI: G. Paschmann),
ASPOC, the Active Spacecraft Potential Control experiment (PI: W. Riedler)
PEACE, the Plasma Electron and Current Analyser (PI: A. Fazakerley).
CIS, the Cluster Ion Spectrometry Experiment (PI: H. Reme),
RAPID, Research with Adaptive Particle Imaging Detectors (PI: B. Wilken).