Second Double Star satellite successfully launched (Forwarded)

European Space Agency
Press Release No. 43-2004
Paris, France 26 July 2004

Second Double Star satellite successfully launched

Yesterday, 25 July at 09:05 CEST (15:05 local time, 0305 UTC) the Chinese
National Space Administration successfully launched Tan Ce 2, the second of the
Double Star science satellites. This marks the latest important milestone in the
scientific collaboration between China and the European Space Agency.

Tan Ce ("Explorer") 2 was launched from the Taiyuan spaceport west of Beijing
(Zhangye province) using a Long March 2C rocket. The launch, initially scheduled
for today 26 July, took place one day earlier in order to avoid adverse weather
conditions expected in the days to come. The spacecraft will join Tan Ce 1,
which was launched on 29 December 2003, to complete the Double Star configuration.

About 8 hours after launch the two solid booms holding the magnetometers were
successfully deployed. In the next few weeks, all spacecraft sub-systems will be
checked out and the commissioning of the on-board scientific instrument will follow.

Double Star will operate alongside ESA's quartet of Cluster satellites to
closely study the interaction between the solar wind and the Earth's magnetic
field. Together, these missions will provide the most detailed view to date.
TC-1 is already returning a wealth of scientific data. Back in January, both
missions tracked a coronal mass ejection from the Sun and gathered valuable data
about the Earth's bow shock.

Tan Ce 2 reached its nominal orbit, with perigee at 682 km, apogee at 38,279 km
and inclination of 90.1 deg. The positions and orbit of the Double Star
satellites have been carefully defined to enable exploration of the
magnetosphere on a larger scale than is possible with Cluster alone. One example
of this coordinated activity is the study of the substorms that produce aurorae.

The exact region where these emissions of brightness form is still unclear, but
the simultaneous high-resolution measurements combined under these two missions
are expected to provide an answer.

ESA is contributing eight scientific instruments to the mission, seven of which
are Cluster-derived units.

These are the first ever European experiments to fly on a Chinese satellite. ESA
will also be providing ground segment support, four hours each day, via its
Villafranca satellite tracking station in Spain.

Scientific cooperation between China and ESA goes back quite a long way. A first
Agreement signed back in 1980 facilitated the exchange of scientific
information. Thirteen years later, the collaboration focused on a specific
mission, Cluster, to study the Earth's magnetosphere.

Then, in 1997, came a big step forward. The CNSA invited ESA to participate in
the Double Star dual-satellite mission to study the Earth's magnetic field, from
a perspective different but complementary to Cluster's. The Agreement to carry
out this joint mission was signed on 9 July 2001 by ESA's then Director General
Antonio Rodotà and CNSA Administrator Luan Enjie.

For Professor David Southwood, ESA's Science Programme Director: "Today's
successful launch marks the culmination of these joint efforts and a further
important step forward in this historic collaboration between China and Europe."

Note for editors

More about Double Star:

The Double Star position and orbits have been defined in relation to Cluster,
which are located far away at about a third of the distance from the Moon. The
duo are much closer to Earth. TC-1 in elliptical orbit (550 x 63,780 km) will
operate for 18 months. TC-2 in polar orbit (700 x 39,000 km) will operate for 12
months. This allows an overlap period, the quartet's lifetime having been
extended by three years to end-2005.

ESA is also contributing 8 million euros of funding to the programme. This
covers the refurbishment, rebuilding and pre-integration of the European
instruments, four hours per day data acquisition and the coordination of
scientific operations.

More about Cluster

This ESA mission comprises a quartet of satellites launched on two Russian
rockets during summer 2000, now flying in formation around the Earth. They are
relaying the most detailed ever information in 3D about the impact on Earth of
the solar wind, that perpetual stream of subatomic particles given out by the
Sun which can damage communication satellites and disrupt power supplies.
Operations have been extended to end-2005.

For further information, contact:

ESA Media Relations Division
Paris, France
Tel: +33 1 5368-7155
Fax: +33 1 5369-7690

More information

* Double Star
http://www.esa.int/esaSC/120381_index_0_m.html
* Cluster
http://www.esa.int/esaSC/120383_index_0_m.html
* Chinese space agency
http://www.cnsa.gov.cn/main_e.asp

Related articles

* First Double Star satellite successfully launched
http://www.esa.int/esaCP/SEMCIB374OD_index_0.html

IMAGE CAPTIONS:

[Image 1:
http://www.esa.int/export/esaCP/SEMN..._index_1.html]
On 25 July at 9:05 CEST (15:05 local time) the Chinese National Space
Administration (CNSA) successfully launched TC-2, the second of two scientific
satellites known as Double Star. This is a joint scientific collaboration
between China and the European Space Agency (ESA).

The spacecraft, called 'Tan Ce 2' which in Chinese means 'Explorer 2,' took off
from the Chinese launch base in Taiyuan spaceport, west of Beijing (Shanxi
Province), on board a Long March 2C launcher.

Credits: CNSA/People's Daily Online

[Image 2:
http://www.esa.int/export/esaCP/SEMN...html#subhead1]
Double Star and Cluster complementary orbits. The four Cluster spacecraft are in
the solar wind and Double Star is crossing the bow shock at the same time.

Credits: ESA

[Image 3:
http://www.esa.int/export/esaCP/SEMN...html#subhead2]
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