Mission to map the Aurorae launches 26 July
The final piece of a six-satellite constellation will blast into space on 26 July. Taking off from Taiyuan spaceport, west of Beijing, on a Chinese Long March 2C rocket, the Tan Ce 2 satellite will join Tan Ce 1, and the four Cluster satellites in an investigation of our magnetosphere.
Tan Ce 2 (Explorer 2) is the second craft built for the Double Star programme. Together with Cluster, a group of four satellites launched in 2000, Double Star will be at the disposal of a group of Sino-European researchers who hope to discover more about what happens inside magnetic storms high above the atmosphere. It is the first Chinese mission dedicated to space science.
The orbits of the six craft have been calculated so that all six will be on the night side of the Earth at various times throughout August and September. This region is known as the magnetotail. The six craft will be stacked in orbit at different distances from Earth, an arrangement scientists hope will reveal where it is in the magnetosphere that the storms begin.
During the onset of a storm, large bursts of energy are released from the magnetosphere in a process called magnetic reconnection. This is the process that, in the Sun, is thought to give rise to solar flares. In our magnetosphere, scientists suspect it is a precursor to auroral sub storms: the beautiful displays of Northern and Southern lights. However, the exact origin of these storms has never been confirmed.
Mission scientists say they are hopeful that data from Cluster and Double Star will provide the most detailed, multi-dimensional view of the complex magnetosphere ever obtained, and provide answers to the question about the origin of the Auroral sub storms.
The team is racing against time: NASA has a mission, called THEMIS, scheduled for launch in Autumn 2006 designed to investigate the same question. The ESA also has a mission schedule to investigate the magnetic field, athough it won't get off the gound until 2009.
The Double Star duo is scientifically important on its own as well: it will provides new measurements in key regions of magnetosphere. However, according to one of the principal investigators on the mission, Andrew Fazakerley (MSSL-UCL), the really exciting part is the data it will gather when it joins Cluster in its formation dance above the clouds.
"When Cluster is in the distant magnetic tail and Double Star is in the near tail, we shall be able to see simultaneously for the first time what happens in both of these key regions when the huge amounts of energy that drive the substorms are released," he said. ®
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