IT was the end of a 1.8 billion-mile historic journey - but even then the work has only just begun.

Finally yesterday after five years the Juno space probe arrived in orbit around Jupiter ready to unlock the secrets of the ‘biggest, baddest planet in the solar system’.

Now should all go to plan, Juno’s instruments and camera could provide insights into the history of the solar system and return stunning images of the planet.

But the mission faces the huge challenge of operating the 1.1bn US dollar probe in one of the solar system’s harshest environments where levels of radiation and high-velocity dust and particles will be a constant threat.

Jupiter - named the biggest and baddest planet by the Juno team - also has a ring of dust and rock similar to its neighbour, Saturn, posing a further threat to the probe.

Even to arrive the spacecraft, named after the Roman goddess, had to complete a high-stakes manoeuvre which saw it fire a rocket to slow its 150,000mph (250,000kph) approach to the planet.

Cheers and applause erupted in mission control at Nasa when a signal arrived confirming the burn was complete in the early hours of yesterday morning.

The mission’s chief scientist, Scott Bolton, congratulated his team, saying “you’ve just done the hardest thing Nasa’s ever done” as the technicians and scientists celebrated completing the complex approach procedure.

The spacecraft began the perilous final stage of its journey with a 35-minute blast from its rocket engine.

The probe’s Twitter profile announced: “Main engine burn is go. I’m burnin’, burnin’, burnin’ for you, #Jupiter” adding later “Engine burn complete and orbit obtained. I’m ready to unlock all your secrets, #Jupiter. Deal with it.”

It was a critical period with a risk the probe may have shot past the planet and into oblivion if the scientists’ calculations were not absolutely correct.

They planned to bring the spacecraft within 2,900 miles of Jupiter’s swirling cloud tops, a region of space blasted by the highest levels of radiation in the solar system.

The titanium-armoured probe’s task is to improve our understanding of Jupiter’s formation and evolution by using complex instruments to peer through the thick atmosphere and its famous Great Red Spot.

Juno’s array will study the gas planet’s composition, gravity, magnetic field and the source of its raging 384mph winds, while a panoramic camera will also return images of the planet in detail never seen before.

Scientists hope that analysis of Jupiter’s interior structure will ultimately help them understand the history and formation of the wider solar system.

It will be some days before Juno begins beaming data and images back to Earth, as the spacecraft’s camera and other instruments were switched off for arrival.

The solar-powered probe’s large solar panels were turned away from the Sun for the final approach before being repositioned to breathe life back into the systems.

Juno tweeted: “All rays on me. My solar panels now face the sun. I’m the farthest solar-powered spacecraft from Earth. #Jupiter”

The previous record for a close approach to Jupiter was set by Nasa’s Pioneer 11 spacecraft which passed by the planet at a distance of 27,000 miles in 1974.

Only one previous spacecraft, Galileo, which visited Jupiter and its moons from 1995 to 2003, has orbited the planet.

Juno was launched into space from Cape Canaveral, Florida, on August 5 2011.