Farewell Rosetta: 'bittersweet' end for space probe

It was a difficult day for Matt Taylor, a project scientist with the European Space Agency, as he watched his beloved space probe crash land and die.

After a 12-year odyssey through the solar system, the Rosetta spacecraft went downin a blaze of glory.

The probe's course across outer space came to an abrupt endSept. 30, in a collision course withthe distant, icycomet it had been tracking for more than two years.

"It was a bittersweet feeling," said Taylor, who was in Edmonton Tuesday to speak at the University of Alberta about his role in the mission.

"We know that we've achieved something fantastic. But also you've lost something.

"This project, you were on it 24/7, there was always something going on, and now that's gone. It's like losing a member of the family."

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The spacecraft spent more than10 years chasing acomet named67P/Churyumov-Gerasimenko,800 million kilometres from Earth, before landing a probe on it in November 2014.

Launched on March 2, 2004, the Rosetta travelled nearly eightbillion kilometres, a journey which included three Earth flybys, a near brush with the surface of Mars and two asteroid encounters.

Before its demise, the craft had endured 31 months in deep-space hibernation on the most distant leg of its journey, and survived the harsh environment of the comet for 786 days.

'Herding cats'

Behind the scenesback on Earth, Taylor worked as a key intermediary between the mission's engineers and scientists.

"I try and make sure that what the scientists want gets done within the constraints of what is available from an operational perspective," Taylor said.

"But what it really means is I have to try and make all of the scientists behave sensibly and walk in one direction which is not really an easy task. It's like herding cats."

With all of the scientific instruments on one side of the aircraft, research real estate was limited. Much of his workload was negotiating between researchers, to ensure every ounce of data was captured and accounted for.

"You have to negotiate with both scientists and say, "this week we'll do you, and next week, we'll do you," Taylor said.

"It sounds easy but, frankly,if you'd seen some of the discussions we've been having in the last twoyears, it's not easy."

Final destination

After landing on the comet's rocky surface, a lack of sun exposure meant the probe's batteries ran out, forcing it offline.

It had effectively been out of contact since then. The loss of power signalledtheswan song for the one-way mission.

The Rosetta would join the probe, which was found lodged in an inky crevasse on the surface of the comet, 91 kilometres below.

All contact with Rosetta was lost on impact, but not before some stunning data was beamed back to Earth.

The images and measurements gathered throughout the mission provide valuable clues about the formation of the solar system, and the origin of life.

'That blows my mind'

Some of the most unexpected and important results, according to the space agency, are "linked to the gases streaming from the comet's nucleus," including the discovery of molecular oxygen and nitrogen, and "water with a different 'flavour' to that in Earth's oceans.

"We look at comets as being a viable seed at the beginning of the solar system to provide the ingredients of life," Taylor said.

"So what we've found from the cometthe different molecules, the different organics really link these things to providing the ingredients for life on earth, and for methat's the big thing."

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Taylor says the organic matter on the earth's surface provides scientists a rare glimpse into what the solar system looked like 4.5 billion years ago.

"Some of the gases we sniff and some of things we taste from the comet, using the probe, feed into how our solar system was, even beforethe sun was formed," Taylor said.

"And that blows my mind."