Saturday, 13 June 2015

22:28 CEST on board Rosetta: The orbiter’s Electrical Support System Processor Unit (ESS) starts receiving radio signals from Philae, approximately 200km beneath Rosetta on the surface of Comet 67P/Churyumov-Gerasimenko.

22:28 CEST on board Rosetta: Spacecraft immediately starts relaying Philae data to Earth via NASA’s 70m deep-space antenna at Goldstone, California. One-way light time is 16.8 minutes, so signals start arriving at about 22:45 CEST on Earth and are immediately relayed to ESOC, Darmstadt, Germany.

Just after 22:45 CEST in Planetary Missions Dedicated Control Room, ESOC: Achim Zschaege, the on-duty spacecraft controller watching telemetry downloading from Rosetta, notices some alarms that had been specially set on some Lander ESS parameters. These had been implemented shortly after separation (in November 2014) to ensure any Lander contact would not be missed. After confirming this was, indeed, correct, and that lander telemetry were being received, he consults an ‘Action Sheet’ kept on hand since 15 November 2014 (when Philae entered hibernation on the comet) to determine what to do.

23:00 CEST ESOC: As defined on the ‘Action Sheet’, the Achim telephones the Rosetta on-call spacecraft operations engineer, Jake Urbanek, at his home near Darmstadt. He reports the news.

23:30 CEST at Jake’s home: Jake calls Rosetta Spacecraft Operations Engineer Armelle Hubault at her home to confirm that the Lander had switched on and transmitted telemetry.

23:45 CEST at Armelle’s home: Armelle confirms the news by calling the Lander Team on a pre-agreed phone number. Lander team confirms Lander is back! Armelle also rings Sylvain Lodiot, the Rosetta Spacecraft Operations Manager, who then rings Paolo Ferri, ESA’s Head of Mission Operations. Paolo subsequently relays the information to the rest of the Rosetta science and operations managers.

Armelle reports: “I had just brushed my teeth and was heading to bed when the phone rang. Seeing Jake was calling, I picked up the phone and said: ‘This has to be bad news. We’ve got a safe mode, don’t we?’ ”

“He replied: ‘Well, maybe not. Maybe it’s good news!’ And, yes, it was.”

Editor’s note: After this weekend’s news, the Rosetta Flight Control Team today have switched into high gear, with a great deal of coordination work now being carried out with the flight dynamics experts at ESOC as well as with the Rosetta Science Ground Segment (RSGS/ESAC), the Philae Lander Control Centre team (DLR Cologne) and the lander science operations centre (SONC), at CNES/Toulouse. We’ll post updates here as we get them.

Listen to the audible control room alarm used at ESOC for Rosetta: