The European Space Agency’s Rosetta spacecraft has been crash-landed onto a comet it has been orbiting for the past two years.

The collision officially brings to an end the craft’s eight-billion kilometre journey and one of the most successful space exploration projects of recent decades.

Rosetta hit the comet’s surface at around 11.40am Irish time but because it is 720 million km from Earth, it took another 40 minutes before the signal of the impact was received.

Although the impact was only at 2km/hr, the craft was not designed to withstand any bumps.

Rosetta will remain crumpled and lifeless on the surface of the comet as the object, a dirty chunk of ice and dust measuring 4.5km across, carries it on repeated circuits of the solar system that may continue for millions of years.

The decision to crash the spacecraft was taken because the comet is now heading so far from the Sun that soon its solar panels will not be able to generate enough power to keep it functioning.

Rosetta gathered extra data and captured fresh images as it dropped towards the pit covered Ma’at area of the surface, and sent them back to Earth prior to impact.

The crash landing is expected to bring a wealth of new information to the European Space Agency before the mission end.

A lot of information about the formation of the solar system is "trapped" in comets, according to Laurence O'Rourke, Rosetta Science Operations Manager at the ESA.

He said that had been an exciting but also a sad day as Rosetta made its planned crash landing.

Speaking on RTÉ's Six One, Mr O'Rourke said: "We've been flying around this comet for two and a half years now, getting closer and closer, but we've never flown below a thousand metres and today we did that and the science we got all the way to just a few meters from the surface.

"We got images up to five to ten meters from the surface and they are gold dust for us."

He said that only 5 to 10% of the data from the spacecraft has been analysed:

"Of course, big questions have been answered, but there are so many others that they raise," said Mr O'Rourke. 

"The data tells us the basic building blocks that existed in the formation, but not only that, it tells us alot about how life came to the earth and how water came to the earth."

Mr O'Rourke said the data will exist for generations to come and his job, over the next few years, is to analyse the remaining data and to make sure it's made available.

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Rosetta was aimed to crash into the head of the comet to allow it the first chance to get pictures up close of the surface and holes on the comet upon descent.

The spacecraft was launched in 2004 and immediately embarked on a ten-year, 6.5bn kilometre journey across the solar system to meet comet 67P Churyumov-Gerasimenko.

It reached the comet in August of 2014, and spent months orbiting, mapping and studying the surface.

It then dropped its landing probe Philae onto the surface on 12 November that year as the comet hurtled towards and around the Sun.

However, the probe bounced and ended up in a dark crevice, which meant it was unable to recharge its batteries.

It did manage to get the unprecedented data it had gathered back to Earth before the power ran out.

Philae’s exact location was only discovered by Rosetta in recent weeks.

Collectively the 21 instruments on board Rosetta and Philae have gathered a treasure trove of new scientific data.

It is now known the comet is rubber duck shaped, porous and light, has a dusty surface with ice below, and was formed by the collision of two smaller comets.

It was also discovered that contrary to one theory, it is unlikely comets were the main source of water on Earth, but likely played a role in seeding life on our planet.

Although Rosetta's space mission ended today, it is expected that analysis of the data will continue for decades to come.