ESA Director General Antonio Rodotà and Luan Enjie, Administrator of the Chinese National Space Administration (CNSA), signed the official protocol that will enable European experiments to be installed on Chinese satellites for the first time.

"This agreement marks a significant advance for international co-operation in the exploration and peaceful use of outer space," said Mr. Rodotà. "It is one of the most important landmarks in East-West scientific collaboration since ESA and the People's Republic of China first agreed to exchange scientific information more than 20 years ago."

Double Star will follow in the footsteps of ESA's ground-breaking Cluster mission by studying the effects of the Sun on the Earth's environment. By conducting joint studies with Cluster and Double Star, it should be possible to increase the overall scientific return from both missions.

A key aspect of ESA's participation in the Double Star project is the inclusion of 10 instruments that are currently flying on the four Cluster spacecraft. A further eight experiments will be provided by Chinese institutes.

Six of the eleven principal investigators on Cluster have agreed to provide flight spares or duplicates of the experiments that are currently revolutionizing our understanding of near-Earth space. This reuse of Cluster instruments has a number of advantages for both European and Chinese scientists.

"By flying identical experiments to those on Cluster, we can reduce costs and development time," explained Alberto Gianolio, ESA project manager for Double Star. "This will minimise risk and help us to ensure that we are able to meet the spacecraft development schedule."

"We hope that it will be possible to make co-ordinated measurements with both Cluster and Double Star," said Cluster project scientist Philippe Escoubet. "For example, we would hope to carry out a joint exploration of the magnetotail, a region where storms of high energy particles are generated. When these particles arrive at the Earth, they can cause power cuts, damage satellites and disrupt communications."

ESA has agreed to contribute 8 million Euros to the Double Star program. This funding will be used for refurbishment and pre-integration of the European instruments, acquisition of data for 4 hours per day and co-ordination of scientific operations.

Double Star will be the first mission launched by China to explore the Earth's magnetosphere -- the magnetic bubble that surrounds our planet. As its name suggests, Double Star will involve two satellites, each designed, developed, launched and operated by the Chinese National Space Administration, flying in complementary orbits around the Earth.

This orbital configuration will enable scientists to obtain simultaneous data about the changing magnetic field and population of electrified particles in different regions of the magnetosphere.

The duo is expected to be launched by Chinese Long March 2C rockets in December 2002 and March 2003. This schedule may enable them to operate alongside ESA's Cluster mission -- a mini-flotilla of four identical spacecraft that were launched into elliptical orbits around the Earth in the summer of 2000.

The "equatorial" spacecraft (DSP-1) will be launched into an elliptical orbit of 550 x 60,000 km, inclined at 28.5 degrees to the equator. This will enable it to investigate Earth's huge magnetic tail, the region where particles are accelerated towards Earth's magnetic poles by a process known as reconnection.

The "polar" satellite (DSP-2) will concentrate on physical processes taking place over the planet's magnetic poles and the development of aurorae (Northern Lights). It will follow a 350 x 25,000 km orbit that carries it around the Earth once every 7.3 hours.

The European experiments to be flown on Double Star are:

FGM - the Fluxgate Magnetometer (Imperial College, London and IWF, Graz) - 2 instruments.

EPS - the Energetic Particle Spectrometer (IDA, Braunschweig) - 2 instruments.

HIA - the Hot Ion Analyser based on the Cluster Ion Spectrometer (CESR, Toulouse) - 1 instrument.

ASPOC - Active Spacecraft Potential Control(IWF, Graz) - 1 instrument.

PEACE - Plasma Electron And Current Experiment (MSSL, University College London) - 2 instruments.

STAFF/DWP - Spatio-Temporal Analysis of Field Fluctuation experiment/Digital Wave Processing experiment (CETP Vélizy/Sheffield University) - 1 instrument.

NAI - Neutral Atom Imager (National University of Ireland, Maynooth) - 1 instrument.

10-Jul-2001