When Rosetta was launched more than a decade ago, it was a dry-as-dust science story -- an unmanned spacecraft and its research payload were being launched to investigate a comet.

But when the Rosetta mission last week reached a climax, the story had changed from the humdrum to an event that captivated the world.

It had become a tale of heroics in deep space, with the secrets of the Solar System at stake.

After a trek of 6.5 billion kilometres (four billion miles), alone in the bitter chill of deep space, the little robot Philae battled to survive and complete its task while its mother ship orbited anxiously above.

Drama and romance had been stitched into the fabric of the Rosetta mission way back in 1993. That was when European space ministers gave the risky, 1.3-billion-euro ($1.6-billion) scheme their approval.

But it took the two great information tools of the early 21st century -- the Internet and social media -- to bring these elements to the fore, and make the expedition relevant for billions.

"Rosetta marks a watershed" in the European Space Agency's strategy to connect with the public, ESA communications chief Fernando Doblas told AFP.

"We are living in a world where people no longer want to receive information passively. You have to be active in your information."

Slick webcasts from mission control in Darmstadt, Germany combined with easy-on-the-astrophysics talks about the importance of the mission.

The scientists spoke mainly in Europe-accented English, using words that were simple but passionate. Not a white coat was in sight.

What was the point of the landing, they were asked.

Get this, they said: by analysing a comet, Philae would probe the primeval material of the Solar System... the ancient water and carbon which may even have seeded Earth with the means to make life.

"Comets are treasure chests," said Mark McCaughrean, senior ESA scientific advisor, before he fed us the jaw-dropping idea: "We could be comet stuff ourselves."

There were graphics and cartoons -- including a hugely-followed series for children (http://www.esa.int/spaceinvideos/Videos/2014/11/Once_upon_a_time_preparing_for_comet_landing) -- and a competition to name the probe and its landing site.

But it was the tweets that especially humanised the mission, creating a narrative of a plucky little scout and its caring mother.

"My #lifeonacomet has just begun," Philae said as, alone in deep space, its battery power ebbing, it faded away like a sickly child.

"S'ok Philae, I've got it from here for now. Rest well...," Rosetta said soothingly.

The handle @Philae2014 notched up 383,000 followers and that of @ESA_Rosetta 277,000 -- a far greater total, combined, than @Madonna.

- From Buck Rogers to robots -

Providing a human dimension to space exploration is not, of course, new.

In the "right stuff" days in the early 1960s, a disparate group of US pilots were recast as the Mercury Seven, representing America in the gladiatorial combat of outer space against the Soviets.

But until now, the media experts had failed to weave an emotional tale for unmanned exploration, which really is where the future lies in space.

The narrative had invariably been about technical challenge and gee-whizzery -- as seen in the video (http://www.youtube.com/watch?v=XRCIzZHpFtY) for NASA's Curiosity rover, which landed on Mars in 2012.

If the human angle and social media were a savvy choice for the Philae landing, "it wasn't an easy one to make" for an agency steeped in austere scientific tradition, admitted Dolbas.

And, like Philae's landing, the choice was not without risks.

London-born astrophysicist Matt Taylor -- a colourful figure who has a tattoo of Philae on his leg -- found himself in a tweetstorm for wearing a shirt with scantily-clad women on it, which critics lashed as sexist.

Exhausted and stressed at the peak of the landing saga, Taylor shed tears on camera and apologised if he had caused anyone any offence. Yet that, too, told us that behind the science lies the humanity.