The Juno team celebrates after receiving confirmation from the spacecraft that it had successfully completed the engine burn and entered orbit of Jupiter, Monday, July 4, 2016 in mission control of the Space Flight Operations Facility at the Jet Propulsion Laboratory. The Juno mission launched August 5, 2011 and will orbit the planet for 20 months.

After a five-year voyage across 1.8bn miles (2.8bn km), Nasa’s Juno spacecraft has reached Jupiter and successfully entered its orbit.


Braving intense radiation and a field of space rocks, the probe inched into the orbit of the largest planet in the solar system at 03.18 GMT.

The manoeuvre was extremely complex, with the craft first having to slow down and then turn off its engines to enter Jupiter’s orbit at exactly the right moment.


“You’re the best team ever! We just did the hardest thing Nasa has ever done,” said Scott Bolton, principle investigator of the Juno mission.

Speaking at a press conference shortly later, Diane Brown, Juno’s project manager, said “It’s overwhelming.”

“The risks that were overcome, it’s amazing. The more you know about the mission the more you know about how tricky it was.”

“To know we can go to bed tonight not worrying about what is going to happen tomorrow, is just amazing,” she said.


Juno’s mission is to peer through Jupiter’s cloud-socked atmosphere and map the interior from a unique vantage point above the poles. Among the lingering questions: How much water exists? Is there a solid core? Why are Jupiter’s southern and northern lights the brightest in the solar system?

“What Juno’s about is looking beneath that surface,” Bolton said before the craft’s arrival. “We’ve got to go down and look at what’s inside, see how it’s built, how deep these features go, learn about its real secrets.”

The fifth rock from the sun and the heftiest planet in the solar system, Jupiter is what’s known as a gas giant — a ball of hydrogen and helium — unlike rocky Earth and Mars.

Bristling with instruments, Juno will peer deep beneath Jupiter’s clouds to learn how the planet formed; what drives its brilliant aurorae; and how its complex weather systems produce the giant red spot and the swirling, enigmatic stripes that decorate its outer layers.

Juno’s most sensitive electronics are encased in a titanium vault to shield them from lethal radiation belts that are most intense around Jupiter’s equator. To avoid the worst of the circuit-frying environment, Juno will perform highly elliptical orbits that pass over the north and south poles before retreating to a distance of nearly 2m miles. Even so, some equipment onboard will be cooked by radiation long before the mission is over.

Over 37 orbits lasting 14 days each, Juno will come within 2,600 miles of Jupiter’s cloud tops. As cameras and microwave instruments map what lies beneath, scientists will monitor subtle shifts in the frequency of Juno’s transmissions, caused by variations in the planet’s gravitational field due to its uneven internal structure. From the measurements, researchers hope to confirm whether or not Jupiter has a solid core.