No. 1 - Instrument Commissioning Started
26 Jan 2004 11:00The first Double Star spacecraft was successfully launched from Xichang, Southern China, on 29 December 2003 at 19:06 UT. The final operational orbit is 570 by 78 970 km, with an inclination of 28.5 degrees. Due to an over-performance of the upper stage the apogee is about 12 000 km more than expected.
This should not affect the scientific objectives. Furthermore, the spacecraft will now observe the Earth bow shock, which was not in the original scientific objectives. A preliminary estimate reveals that that the number of conjunctions with Cluster has decreased slightly, but this is compensated by the longer time interval for each individual conjunction.
One solid boom, carrying the fluxgate magnetometers (FGM), has been deployed successfully. The other one, carrying the search coil (STAFF/DWP), is still un-deployed after an initial attempt to deploy it. Chinese spacecraft engineers are investigating the source of the problem and will make another attempt in the next few weeks. This, however, does not affect the stability of the spacecraft and the spin axis is as expected close to the North ecliptic pole.
Instrument commissioning started in early January.
Commissioning Status: Tests started on 8 January and after 4 days the instrument electronics were checked-out successfully.
Commissioning Status: Has finished its initial commissioning
Both instruments have detected an electromagnetic noise, which is likely related to the boom asymmetry causing solar array shadowing; an investigation is on going to identify the source and try to eliminate it.
PEACE (electron detector)
Commissioning Status: Started first electronic tests on 20 January and is working nominally. Some software tuning is still on going to optimize the on-board compression algorithm.
ASPOC (ion emitter)
Commissiong Status: Covers were opened successfully on 5 January and instrument commissioning will began on 24 January
HIA (ion detector)
Commissiong Status: Commissioning will begin in first half of February
All three European experiments are being delivered to Beijing for the second Double Star spacecraft, which will start its integration early February for a launch in July 2004.