That was *very* nerve wracking (probably the longest 26 minutes of my life) – but Herschel is on its way!
Both spacecraft are alive and well and talking to the ground controllers.
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 15:37 CEST at an altitude of about 1140 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.
A group of 150 people attended the launch party at the Rutherford Appleton Laboratory in Didcot, Oxfordshire (the home of the SPIRE instrument), and in addition to the launch itself, we had a number of talks beforehand on the satellites themselves and what we expect them to provide in terms of scientific payoff. The room was quiet as a mouse during launch, as you might expect – and raptous applause followed when we received word that Herschel and Planck had successfully separated from the Ariane. Copious amounts of champagne were consumed afterwards, as you might imagine!
Now that Herschel is safely on its way, the hard work starts – the commissioning phase! For us on the SPIRE, the first milestone is May 22nd, when the instrument is switched on – several of our team will be at the Mission Operations Centre in Damstadt to oversee this.
But today, it’s time to sit back and relax(-ish)!
(Apologies for the lack of updates during launch – no internet connection! Photos from the launch party to follow.)
P.S. I even got interviewed for BBC Radio 4, for a documentary they will be producing on Herschel and Planck. Hope it makes the editing cull. 😉