Rumba and Tango manoeuvre in step
11 August 2000
Following the successful launch of the second pair of four ESA Clustersatellites at 13:13 CEST on 9th August, Rumba and Tango are heading towards their final operational orbits.The first step in this celestial dance was to increase the spin rate of both spacecraft from 5 to 13.7 revolutions per minute and then modify their attitude in preparation for the first apogee raising manoeuvre. This took place out of ground station coverage at 10:53 (CEST) on 10 August for Tango and at 15:59 (CEST) for Rumba.
Telemetry subsequently received at Kiruna (Sweden) and Villafranca (Spain) showed that both spacecraft had reached their correct orbits, with a perigee of around 239 km and an apogee of 23 199 km.
The next step in the sequence of four apogee raising manoeuvres was successfully accomplished this morning. A burn of the spacecraft main engine took place at 5:40 (CEST) for Rumba and at 6:58 (CEST) for Tango, with ground station coverage only at the beginning of the manoeuvre. As a result, the spacecraft orbits were elongated still further, with a perigee of about 240 km and apogees of about 33 000 km and 34 000 km.
"Everything is exactly as we want it to be at this stage," said Cluster operations manager Manfred Warhaut at the European Space Operations Centre in Darmstadt.
In order to bring the spacecraft to their operational orbits, another two apogee raising manoeuvres are scheduled for early tomorrow morning (12 August) at 1:34 and 2:18 CEST and tomorrow afternoon at 18.35 and 18.37 CEST. A much longer engine burn to alter their orbital inclination from 64.8 degrees to 90 degrees will take place on 13 August.
The space quartet should be complete on 15 August when Rumba and Tango join their two companions (Salsa and Samba).
