ESA's Rosetta Makes Space History: Spacecraft Reaches Comet After Four-Billion Mile Journey

The Rosetta probe has successfully reached the orbit of a speeding comet after chasing it for a decade, a spectacular first in space history.

The European Space Agency live-streamed the final burn that aligned Rosetta with the comet 67P/Churyumov–Gerasimenko.

The Rosetta rendezvous began with a quick engine thrust and now, the spacecraft will begin a triangular path around the comet. Each leg will take three to four days to complete and is about 62 miles in length, according to the ESA.

The incredible 10-year journey has taken the probe over a distance of four-billion miles through deep space.

If the all goes according to plan over the next few weeks, Rosetta will become the first probe to ever orbit a comet and drop a lander on its surface on 11 November.

"For the first time, we will rendezvous with a comet, for the first time we will escort a comet as it passes through its closest approach to the sun and — the cherry on the top — for the first time, we will deploy a lander," Rosetta project scientist Matt Taylor told Space.com.

"The rendezvous is therefore a key milestone in the mission."

Rosetta was first launched in March 2004 and was put into hibernation in June 2011. In January, the craft woke up to complete its journey to the comet.

The gravitational pull of the comet, which was discovered in 1969, is so weak that the lander, Philae, must attach itself with an explosive harpoon.

Throughout August, Rosetta will fly around the comet in a triangular orbit to give scientists time to map its surface, as well as its shape and the strength of its gravitational field.

Rosetta will then move closer to the surface, and settle into a standard circular orbit.

Taylor, who is working on the Rosetta mission at ESA in the Netherlands, told the Guardian: "The time pressure at the moment is phenomenal. It's a race against the clock to learn about the comet and select a landing site. We have to land before the comet becomes too active."

"We'll get an inference of what's possible in September, but we won't want to land near the neck of these two parts of the comet," he added. "We need the best communications with the orbiter and also to maximise the sunlight the lander receives to give it the best chance to survive as long as possible."