Nasa's Juno spacecraft carrying Lego Galileo nears Jupiter

Robotic spacecraft carries Lego figures of 17th century Italian astronomer, Roman god Jupiter and his wife Juno

Artist's impression of Juno approaching Jupiter. The probe will have to survive the radiation of the planet's magnetic field to complete the mission (PA)

Nasa has released a new image of the Juno spacecraft as it nears Jupiter.

The probe is expected to reach the gas planet on 4 July, just under five years since it was launched.

On 11 June, Juno turned itself on and began sending and receiving data around the clock as it prepares for the end of its 1.4 billion-mile journey from Earth.

It will enter a long polar orbit flying to within 2,900 miles (4,667 km) of the planet's swirling cloud tops.

Unusually, on board the robotic spacecraft there are three passengers – special edition Lego figures depicting the 17th century Italian astronomer Galileo Galilei, the Roman god Jupiter and the deity’s wife Juno.

The figures are made out of aluminium instead of plastic so they can withstand the extreme conditions of spaceflight.

A plaque dedicated to Galileo provided by the Italian Space Agency is also on board.

No previous spacecraft has orbited so close to Jupiter as two previous attempts were destroyed after plunging through the planet’s gaseous atmosphere.

To complete the mission Juno will have to survive a radiation storm generated by Jupiter’s magnetic field. The planet has the harshest radiation environment in the Solar System.

To cope with the conditions, Juno is protected with special radiation-hardened wiring and sensor shielding.

Its all-important "brain" – the spacecraft's flight computer – is housed in an armoured vault made of titanium and weighing almost 400 pounds (172kg).

Dr Scott Bolton, Juno's principal investigator from Southwest Research Institute in San Antonio, US, said: "We are not looking for trouble, we are looking for data.

"Problem is, at Jupiter, looking for the kind of data Juno is looking for, you have to go in the kind of neighbourhoods where you could find trouble pretty quick."

The craft was launched into space by an Atlas V rocket from Cape Canaveral in Florida on 5 August 2011.

Additional reporting by PA