Double Star is a joint

satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisotope ...

based space mission by the

China National Space Administration China National Space Administration (CNSA; ) is the government agency of the People's Republic of China that is responsible for civil space administration and international space cooperation, including organizing or leading foreign exchanges ...

(CNSA) and the

European Space Agency , owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (1205 ...

(ESA). It is the first space mission launched by China to investigate

Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...

magnetosphere In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior dynam ...

. It consists of two satellites: an Equatorial satellite (TC-1) and Polar satellite (TC-2). Double Star follows in the footsteps of ESA's

Cluster mission Cluster II is a space mission of the European Space Agency, with NASA participation, to study the Earth's magnetosphere over the course of nearly two solar cycles. The mission is composed of four identical spacecraft flying in a tetrahedral form ...

by studying the effects of the Sun on the Earth's environment. After a nominal mission of one year (from the launch of TC-2 in July 2004), the Double Star mission was extended twice by both agencies until the end of September 2007.

Overview

The Double Star mission uses two satellites in Earth orbit - each designed, developed, launched, and operated by the

. 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 four hours per day and co-ordination of scientific operations. This schedule enabled Double Star to operate simultaneously with ESA's

. The first equatorial spacecraft (Double Star 1, also known as DoubleStar1, Tan Ce 1, Chinese for Explorer 1, TC-1) was launched by a

Long March 2C The Long March 2C (LM-2C), also known as the Chang Zheng 2C (CZ-2C), is a Chinese orbital launch vehicle, part of the Long March 2 rocket family. Developed and manufactured by the China Academy of Launch Vehicle Technology (CALT), the Long Ma ...

launch vehicle on December 29, 2003, at 19:06 UT. Its purpose was to investigate Earth's huge 'magnetotail', the region where particles are accelerated towards the planet's magnetic poles by a process known as 'reconnection'. The second polar spacecraft (Double Star 2, also known as DoubleStar2, Explorer 2, Tan Ce 2, TC-2) was launched July 25, 2004 at 07:05 UT, also by

. It will concentrate on physical processes taking place over the magnetic poles and the development of

aurorae An aurora (plural: auroras or aurorae), also commonly known as the polar lights, is a natural light display in Earth's sky, predominantly seen in polar regions of Earth, high-latitude regions (around the Arctic and Antarctic). Auroras display ...

. The mission formally ended on October 14, 2007, when the TC-1 spacecraft re-entered the Earth's atmosphere after being decommissioned (an unavoidable consequence of its equatorial orbit). The TC-2 spacecraft and payload continues to operate though financial support from ESA/STFC has been discontinued.

Launch and orbits

TC-1 was launched into an equatorial elliptical orbit of 570 x 78 970 km with inclination 28.5° to the equator from the

Xichang Satellite Launch Center The Xichang Satellite Launch Center (XSLC), also known as the Xichang Space Center, is a spaceport of China. It is located in Zeyuan Town (), approximately northwest of Xichang, Liangshan Yi Autonomous Prefecture in Sichuan. The facility beca ...

. This apogee of this mission was the deepest into space China had ever sent a spacecraft at that time. The TC-2 spacecraft was launched into a polar elliptical orbit of 700 x 39 000 km, inclination 90° to the equator from

Taiyuan Satellite Launch Center The Taiyuan Satellite Launch Center (TSLC) also known as ''Base 25'' (), is a People's Republic of China space and defense launch facility (spaceport). It is situated in Kelan County, Xinzhou, Shanxi Province and is the second of four launch ...

References

External links

ESA page

ESA Science and Technology page

Imperial College Double Star website

{{Use British English, date=January 2014 China National Space Administration Earth observation satellites of the European Space Agency 2003 in China 2004 in China Earth observation satellites of China Twin satellites Geospace monitoring satellites