Cluster team to participate in Chinese magnetosphere mission
17 March 2000Following the recent visit of a Chinese delegation to ESA Headquarters and ESTEC, European scientists are looking forward to participation in a 'mini-Cluster' mission, known as Double Star.
The 100 page Phase A report on the proposed Double Star flight was presented by the Chinese scientists to representatives of ESA and many of the institutions involved in ESA's Cluster II mission on 9 - 10 March. This was followed by a visit to ESTEC, which included a tour of the spacecraft test facilities.
If the Chinese authorities give the go-ahead for Double Star, the two cylindrical satellites will be launched before the conclusion of the Cluster mission. The first Long March 2-C rocket will lift off in June 2002 to place the 'Equatorial' satellite into a 550 x 60,000 km orbit, inclined at 28.5 degrees to the equator. This will be followed before the end of the year by a 'Polar' satellite with a 350 x 25,000 km orbit which takes it over the most interesting regions of the magnetosphere, the polar cusps.
Although the 180 kg satellites are much smaller than their Cluster cousins, they will be carrying a selection of the same instruments built for the European spacecraft, in addition to their Chinese payload. On board the Equatorial satellite will be three Cluster instruments - FGM, PEACE and ASPOC - as well as a European-built neutral atom imager.
Five of the eight experiments on board the Polar satellite will be identical or similar to those on Cluster. They are ASPOC, FGM, PEACE, RAPID and the Hot Ion Analyser which is part of the CIS instrument.
Most of these instruments will be Cluster flight spares, and since the cost of the launches and the satellites themselves is being borne by the Chinese, the Double Star mission represents an excellent, low cost opportunity for European scientists to receive valuable new data about the influence of the Sun on near-Earth space.
According to Cluster II Project Scientist, Philippe Escoubet, Double Star is an ideal complement to the Cluster mission.
"If they launch in June 2002, there will be at least six months overlap with Cluster," he explained. "This means that we will have simultaneous measurements from six points instead of four."
"There will be two more sets of data from satellites which are carrying many of the same instruments as Cluster, but which are following different orbits," he added. "On Cluster we do not have a spacecraft in an equatorial orbit, so data from the Chinese satellite would be particularly valuable. The complementary orbits and experiments used by Double Star will provide an exciting extra dimension to Cluster's multipoint measurements."