The fluorescent green zigzag on the screen in the control room at the European Space Agency (ESA) command centre in Darmstadt stopped at 11.19am yesterday, signifying the end to the Rosetta satellite's extraordinary 12-year mission.
There was applause, followed by tearful embraces.
"I was in the briefing room, watching the signal dropping, live. It was a bittersweet moment," Laurence O'Rourke, the Rosetta science operations manager, said. "You see the pulse go from alive to dead . . . It was sad, but when you look at what we did and how much science we achieved, it was well worth it."
Rosetta had begun a 19km descent towards the comet called 67P/Churyumov-Gerasimenko on Thursday night. The spacecraft became the first to orbit a comet in August 2014.
Scientists chose an area of active pits on the smaller lobe of the barbell-shaped comet for the crash landing. Rosetta continued to transmit images until the last moment. It was hoped that a close look at the sink holes would provide knowledge on the inner workings of the comet.
Mr O'Rourke, who is from Killucan near Mullingar, Co Westmeath, has devoted eight years to the project and will continue to interpret data from Rosetta for three years. He is also working on the Plato mission studying exoplanets around other stars and the Asteroid Impact Mission.
Unfortunate position
Mr O’Rourke watched yesterday’s landing with Irish astrophysicist
Susan McKenna-Lawlor
, who was his professor at Maynooth. Ms McKenna-Lawlor’s
Space Technology
Ireland
Ltd company built the electrical support system processor unit for Rosetta.
"Made in Ireland for the Rosetta mission, the ESS was very important because it enabled us to communicate with the Philae lander [which Rosetta dropped onto 67P in November 2014]," Mr O'Rourke said.
Older scientists, some of whom had been with the Rosetta programme since its inception in 1984, spoke after the landing. Bernd Feuerbacher, described as "the father of Philae" said the washing machine-size lander "has been such a brave little boy, sitting up there in a ravine in an unfortunate position, but still doing fantastic science . . . Rosetta and Philae together have changed our understanding of life, of Earth, of the origin of the planetary system."
Elliptical orbit
Marc Bonnet
, a former director of science for ESA, was applauded when he said: “The nice
Rosetta
is now a Sleeping Beauty. Let me wish that a Prince Charming will come one day, maybe from ESA or
Nasa
to wake it up.”
Rosetta was forcibly retired after travelling nearly eight billion kilometres in 12 years. Comet 67P was about to go behind the sun, cutting off communication with Darmstadt.
As Rosetta was not designed to touch down, its structures were probably damaged.
"Rosetta will shut down because it's told to," ESA's senior science adviser Mark McCaughrean told the BBC. "Then it will reboot . . . Then it moves itself off into a piece of software that says, 'Remember the day you woke up, when you were on top of the rocket in 2004? That's where you are today'. So Rosetta could actually survive and keep working, but . . . we won't be able to hear from it."
Comet 67P was from the Jupiter family, Mr O’Rourke said. “It’s on an elliptical orbit around the sun and so it will come back in six years.”
Mr McCaughrean said data sent by Rosetta "confirmed that the comet is full of the raw materials from which life can be made and that could have rained down on the planet Earth when it was young".
