This evening, the Chinese National Space Administration (CNSA) successfully
launched TC-1, the first of two scientific satellites known as Double Star.

The spacecraft, called ‘Tan Ce 1’ which in Chinese means ‘Explorer 1,’ took off
from the Chinese launch base in Xichang, in Sichuan province, on board a Long
March 2C launcher.

ESA has contributed to the Double Star mission by providing eight on-board
scientific instruments. Double Star follows the footsteps of ESA’s Cluster
mission and will study closely the interaction between the solar wind and the
Earth’s magnetic field.

The People’s Republic of China and ESA have a long history of scientific
collaboration. The first co-operation agreement was signed in 1980, to
facilitate the exchange of scientific information. Thirteen years later, the
collaboration focused on a specific mission, ESA’s Cluster, to study the Earth’s
magnetosphere. Then, in 1997, the CNSA invited ESA to participate in Double
Star, a two-satellite mission to study the Earth’s magnetic field, but from a
perspective which is different from that of Cluster and complementary to it.

An agreement to develop this joint mission was signed on 9 July 2001 by ESA’s
Director General, Antonio Rodota, and Luan Enjie, Administrator of the CNSA.

ESA’s contribution to the mission includes eight scientific instruments, of
which seven are spares from the Cluster mission, and support to the ground
segment for four hours each day via ESA’s satellite tracking station in
Villafranca, Spain.

Today’s launch sees the culmination of these joint efforts and marks another
important step in the collaboration between CNSA and ESA. The instruments on
board Double Star are the first ever European ones to be flown on a Chinese
satellite. Together with those built by Chinese scientists, they will work in
synergy with those mounted on board the four Cluster spacecraft.

The positions and orbit of the two Double Star satellites have been carefully
defined to allow the study of the magnetosphere on a larger scale than that
possible with Cluster alone. An example of this co-ordinated activity is the
study of the substorms producing the bright aurorae.

The exact region where they form is still unclear but the simultaneous
high-resolution measurements to be made by Double Star and Cluster are expected
to give an answer.

Professor David Southwood, the Director of ESA’s Scientific Programme, said:
"Double Star is a win-win project. Not only will European scientists participate
in a new mission, at a very low cost, but they will also see an increased
scientific return from the four ESA Cluster satellites. Chinese scientists will
equally benefit of this, since they already participate in the Cluster mission.
These are the great advantages of an historic international collaboration."

More about …

* Double Star overview

* Cluster overview

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[Image 1:]
Double Star logo.

Credits: ESA

[Image 2:]
Double Star Programme (DSP). This mission consists of two satellites, the
equatorial satellite DSP-E, following a 550 x 60,000 kilometre orbit, inclined
at 28.5 degrees to the Equator and the polar satellite DSP-P, following a 350 x
25,000 kilometre orbit inclined at 90 degrees to the Equator.

Credits: Chinese National Space Administration

[Image 3:]
Artist’s impression Cluster II

[Image 4:]
Double Star satellite in its launch configuration. Double Star’s satellite pair
study space weather around the Earth. One satellite circles the Earth’s Equator,
the other flies over the poles.

Credits: Chinese National Space Administration