At 15:49 CEST today, just under 40 minutes after liftoff, Herschel and Planck sent their first radio signals to Earth, confirming that they separated successfully from the launcher and are alive.
Herschel, the upper passenger, was the first to separate from the upper stage of the Ariane 5 at 15:38 CEST at an altitude of about 1150 km over the east coast of Africa. About 1.5 minutes later, the Sylda support structure that enclosed Planck came off and separated. It was followed by Planck at 15:40 CEST at an altitude of about 1700 km slightly East of the east coast of Africa.
The satellites switched on their attitude control and telecommunications systems right after separation, to re-orient themselves and establish contact with Earth for the first time from space. The signals were received by ESA’s 35-m deep space antenna at New Norcia in Australia.
The mission control teams will continue to receive telemetry from Herschel via New Norcia, and for Planck via ESA’s antenna at Perth, also in Australia. Spacecraft Operations Engineers at the Mission Control Centre will use these data to assess the overall health of the satellites after launch.
Almost immediately after telemetry reception starts, engineers will determine the actual trajectory of each satellite so that it can be fine-tuned for planned trajectory correction manoeuvres.