The Rosetta mission, which has for the first time put a spacecraft in orbit around a comet and landed a robotic probe on its surface, has been voted this year's most important scientific breakthrough by the editors of the journal Science.
Rosetta was voted top from a list of 10 scientific breakthroughs which included advances in medicine, robotics, synthetic biology and palaeontology - the discovery that cave art in Indonesia thought to be 10,000 years old is between 35,000 and 40,000 years old.
The European Space Agency mission began 10 years ago when the Rosetta spacecraft was launched. This year, it caught up with comet 67P/Churyumov-Gerasimenko and completed a complex series of manoeuvres to put it into orbit.
The highlight of the mission was the soft landing of its Philae probe on to the surface of the icy object - not once but three times as it bounced twice in the comet's low gravity from its intended landing site.
"Philae's landing was an amazing feat and got the world's attention, said Science news editor Tim Appenzeller.
"But the whole Rosetta mission is the breakthrough. It's giving scientists a ringside seat as a comet warms up, breathes, and evolves."
An instrument on Rosetta has detected water, methane and hydrogen as well as rarer molecules such as formaldehyde and hydrogen cyanide, findings that could indicate whether comets delivered the vital ingredients of life to the early Earth.
"Breakthroughs should do one of two things: solve a problem that people have been wrestling with for a long time or open the door to a lot of new research," said Science deputy news editor Robert Coontz.
The other breakthroughs on the list are:
A series of papers compared the fossils of early birds and dinosaurs to modern birds and revealed how certain dinosaur lineages developed small, lightweight body plans, enabling them to evolve into many types of birds and survive the last major mass extinction about 66 million years ago.
Young blood fixes old
Blood from a young mouse - or even just a factor known as GDF11 from young mouse blood - can rejuvenate the muscles and brains of older mice. The findings have led to a clinical trial with Alzheimer's patients.
Getting robots to co-operate
New software and interactive robots that, for example, instruct swarms of termite-inspired bots to build a simple structure are proving that robots can work together without human supervision.
Mimicking the architecture of a human brain, engineers at the computer company IBM and elsewhere have produced the first large-scale "neuromorphic" chips, which are designed to process information in a similar way to brains.
Two groups this year pioneered methods for growing cells that closely resemble beta cells - the insulin-producing cells of the pancreas - this year, providing an unprecedented opportunity to study diabetes.
Indonesian cave art
Researchers realised that hand stencils and animal paintings in a cave in Indonesia, once thought to be 10,000 years old, were between 35,000 and 40,000 years old. The discovery indicates that humans in Asia were producing symbolic art as early as the first European cave painters.
Using optogenetics - a technique that manipulates neuronal activity with beams of light - researchers showed they could manipulate memories in mice. Deleting existing memories and implanting false ones, they were able to switch the emotional content of a mouse memory from good to bad, and vice versa.
Although they were blasted into space a decade ago, CubeSats - cheap satellites with sides that are only 10cm squared - really took off this year. Once considered to be mainly educational tools, these miniature satellites are now being used to to do some real science.
Expanding the genetic alphabet
Researchers have engineered the gut microbe E.coli so it has two additional "letters" of the genetic code - nucleotides known as X and Y - as well as to the normal G, T, C, and A that make up the standard building blocks of DNA. Such synthetic bacteria may be used to create designer proteins with "unnatural" amino acids.