After a five year journey from Earth, Juno the solar-powered spacecraft squeezed through a narrow band, skimming Jupiter’s surface, avoiding the worst of both its radiation belt and its dangerous dust rings.
It fired its main engine, slowing its velocity, and allowing it to get captured into Jupiter’s hefty orbit.
After it was complete, jubilant scientists fronted a press conference, and tore up a “contingency communication strategy” they said they prepared in case things went wrong.
“To know we can go to bed tonight not worrying about what is going to happen tomorrow, is just amazing,” said Diane Brown, a project manager from NASA’s Jet Propulsion Laboratory.
Scott Bolton, principle investigator of the Juno mission told his colleagues: “You’re the best team ever! We just did the hardest thing Nasa has ever done.”
Now the spacecraft will orbit the planet once every 53 days until October 14, when it will shift to a tighter 14-day orbit. And after about 20 months of learning everything it can about Jupiter’s interior and its atmosphere, it will eventually succumb to the harsh environment and plunge into the planet’s crushing centre.
But right now all that is ahead of us. We watch wide-eyed, eager to learn about the giant planet, and in doing so, learn more about how we all got here.
To find out more, you can check out the article below, or scroll through the rest of this liveblog to see the action, as it happened.
After an epic five year journey, where it slung-shot around the Earth to gather speed and travelled for 2.8bn kilometres, it will now circle Jupiter for 20 months, before plunging to a crushing death in Jupiter’s harsh and dense atmosphere.
Any reports we get from Juno actually happened 48 minutes and 19 seconds earlier – that’s how long it takes light to get from Juno to Earth. As a result, it gets sent directions ahead of time, and is flown essentially on auto-pilot.
Despite Juno’s sensitive electronics being encased in a one-inch thick solid titanium box to shield it from the intense radiation around Jupiter, eventually it will succumb to the harsh environment. At that time – currently estimated to be in about 20 months – it will be commanded to dive into the atmosphere.
But in that time, it will use it’s nine instruments to learn everything it can about Jupiter’s interior and atmosphere.
It will map Jupiter’s gravity and magnetic fields and track how much water is in the atmosphere. Its colour camera dubbed JunoCam will snap close-ups of Jupiter’s swirling clouds, polar regions and shimmering southern and northern lights.
Juno itself is an amazing feat. It’s the first solar powered spacecraft to reach the outer planets. It’s one of the fastest spacecrafts ever made. And it has pulled-off an incredible and dangerous maneuver, entering orbit around the gas giant.
But the really amazing things will be the science it does as it orbits the planet.
One of the big questions is: what’s at the core of Jupiter? Scientists aren’t sure whether it started off as a rocky planetary core, which then gathered all the gas that today makes up most of the planet, or whether it formed from an unstable region in a gas cloud.
Another question scientists hope to answer is how much water is in the planet. For scientists, that’s a measure of how much oxygen there is – locked up as the O in H2O. Based on measurements made from Earth, there seems to be less oxygen on the planet than there is in other objects in that region of the solar system.
If there turns out to be lots of water – and so lots of oxygen – that would suggest the planet formed near the sun. If there is relatively little water, that would suggest it formed further out in the solar system, and migrated in.
How does that eye remain so stable? By diving below the clouds, Juno aims to map the structure and the motion of the atmosphere. That will help scientists see how deep the features we see on the surface penetrate, and figure out how they formed and why they remain for so long.
And now we’ve got up a story, summarising what’s happened so far.
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.
Juno’s success prompted joy at Nasa’s jet propulsion laboratory, where team members had been watching the probe’s progress with bated breath.
“Juno, welcome to Jupiter,” said mission control commentator Jennifer Delavan of Lockheed Martin, which built Juno. In the background, scientists could be seen cheering, clapping and hugging each other.
“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.
About 400 years ago, Galileo discovered that some of the “stars” near Jupiter weren’t moving as expected. He figured out they were actually moons, orbiting Jupiter.
Until now, nobody had seen that system – like a mini solar system itself, almost – up close. But today Nasa released a spectacular video made up of still images taken by Juno as it approached Jupiter, showing the moons orbiting Jupiter.
Project Manager Rick Nybakken got theatrical at the press conference.
He said that before the final maneuver today, Nasa prepared a “contingency communications strategy” – what they would say to the public if things went wrong, presumably. He held that strategy up and tore it to pieces in front of the room.
“Juno sang,” he said. “And it was a song of perfection.”
Rick Nybakken rips up Juno's "contingency communications strategy" to cheers and laughs. pic.twitter.com/qyxknTqnm9
The Juno spacecraft announced on Twitter that it had completed its twist, so that it was now facing the sun, soaking up the solar energy it needs to continue its missions.
All rays on me. My solar panels now face the sun. I’m the farthest solar-powered spacecraft from Earth. #Jupiter
As mentioned earlier, Scott Bolton, leader of the Nasa team behind the successful mission shouted: “You’re the best team ever! We just did the hardest thing Nasa has ever done.”
And on Twitter, people seem to be agreeing with him.
They say “space is hard” which is true, but NASA IS SO FRICKIN’ HARDCORE THEY CAN GET A SPACECRAFT TO JUPITER WITHIN A SECOND OF TARGET
Earlier in the day, before Juno approached Jupiter, Scott Bolton said: “As you can tell it’s not easy for Nasa to get he answers that humanity is seeking here.” But now it looks like they’re much closer to doing so.
And now celebrations are rolling in from around the world. Google has got in on the action just now, updating its Google Doodle:
Over the next 40 minutes, Juno will spin down again from its current five rotations per minute, down to two. Then it will turn around to face the sun again, so it can recharge its batteries. After that it will switch on its main antenna, and it will start communicating properly with Earth. Nasa says locking into that signal from its main antenna could take 20 minutes or more.
Nasa has ended its coverage of the event but stay tuned and we’ll bring you the the last updates as Juno completes its final moves, reactions from people around the world and a final wrap-up of Nasa has achieved today.
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