A spacecraft that has been chasing a comet for more than 10 years will finally catch it up this morning. The Rosetta space probe will begin close-up tests on the comet to find out how it was formed.

It will also prepare to land a robot on its surface.

About to start my final rendezvous burn to arrive at #67P. My next tweet will let you know I've arrived...!

— ESA Rosetta Mission (@ESA_Rosetta) August 6, 2014

Professor Monica Grady from the Open University - who helped to build instruments on board the probe - says it has already thrown up some surprises.

After completing a complex series of nine orbital manoeuvres since the end of hibernation on January 20th, Rosetta is finally in position to rendezvous with the comet.

Orbit entry will take place this morning and will be triggered by a small, but crucial, thruster firing lasting just 6 minutes 26 seconds. The commands were uploaded last night.

This burn will tip Rosetta into the first leg of a series of three-legged triangular paths about the comet. The legs will be about 100 kms long and it will take Rosetta between three and four days to complete each one.

Since its launch from Europe's Spaceport in Kourou, French Guiana on March 2nd 2004, Rosetta has travelled more than six billion kilometres, passing by Earth three times and Mars once, and flying past two asteroids.