A new phase in ESA-China scientific collaboration was officially given the green light today at ESA Headquarters in Paris with an historic agreement between ESA and the Chinese National Space Administration (CNSA) to develop a joint project known as 'Double Star'.

ESA Director General Antonio Rodota and Luan Enjie, Administrator of the CNSA, signed an official agreement that will enable European experiments to be flown on Chinese satellites for the first time.

Artist's concept of Double Star Programme satellites. Photo: ESA

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

"The Double Star programme will be just the first step in substantial cooperation between the Chinese National Space Administration and ESA" said Mr Luan Enjie. "The signing of today's agreement paves the way not only for reciprocal cooperation between scientists, but for the establishment of comprehensive cooperation between the two agencies."

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. Conducting joint studies with Cluster and Double Star should 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 identical to those currently flying on the four Cluster spacecraft. A further eight experiments will be provided by Chinese institutes.

"We hope it will be possible to make coordinated 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 reach Earth, they can cause power cuts, damage satellites and disrupt communications."

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

Illustration of a Double Star satellite with solid booms deployed. Photo: Chinese National Space Administration

"By flying experiments identical 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."

ESA has agreed to contribute 8 million euros to the Double Star programme. This funding will be used for refurbishment and pre-integration of the European instruments, acquisition of data for 4 hours per day and coordination 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 CNSA - flying in complementary orbits around the Earth.

This orbital configuration will enable scientists to obtain simultaneous data on 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 launched into elliptical orbits around the Earth last summer.

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 the planrt'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. It will have a 350 x 25 000 km orbit that takin it round the Earth once every 7.3 hours.