Once upon a time, a spacecraft called Rosetta,

and her brother Philae set off on an adventure, a long, long, journey

to visit a comet called 67P Churyumov-Gerasimenko.

Their journey was inspired by stories they had heard from grandfather, Giotto.

Long, long, ago, men and women on Earth gazed in wonder at comets that appeared in the sky.

What were these mysterious objects?

Some thought they might be caused by Earth breathing into the sky,

but no one knew for sure.

Until the Danish astronomer named Tycho Brahe discovered that comets are very far away.

Much, much further from Earth than the moon.

How could we learn more about these distant objects?

By trying to get close to them.

I was one of the lucky spacecraft to fly very close to the most famous comet of all, Halley's Comet.

Halley's Comet is very special, it is named after Edmund Halley,

who discovered that many comets come back regularly to our sky.

He predicted that one of those comets would return after 76 years, and it did.

Time and time again, Halley's Comet has come back right on schedule every time.

The last time in 1986, I was there.

Together with a bunch of friends from lots of other countries,

we set off to welcome this legendary comet.

I was the bravest of all and flew less than 600 kilometers from the comet 's nucleus.

It was a harsh place but the sight was amazing and I sent pictures back home.

Many more spacecraft have gone looking for comets after us,

like your cousin Stardust, who flew by Comet 81P/Wild,

collected dust particles from the shiny tail and sent them back home to be studied.

Or, one of your other cousins, Deep Impact, who made a crater in Comet 9P Tempel, to see what's under the surface.

Stardust flew by this comet a few years later to look at this famous crater.

We have learned a lot about comets, but much more is still to be discovered.

Comets hold many secrets about the early days of our solar system.

How did planets form?

How did water arrive on Earth?

And you, Rosetta and Philae, are going to find out

by doing what no space probe has ever attempted : orbit a comet and land on it.

Now, it's time to write your story.

With a historic mission ahead of them Rosetta and Philae traveled for ten years.

They 've been dreaming of comets and the adventure that lay ahead.

And they're about to reach their destination.

But that's another story.