Juno spacecraft successfully enters Jupiter's orbit

An artist's rendering of Juno passing over Jupiter (NASA)
An artist's rendering of Juno passing over Jupiter (NASA)

It took five years and 2.8 billion kilometres, but NASA's Juno spacecraft has now entered orbit around Jupiter.

The do-or-die arrival boiled down to a tense period where the probe fired its main engine continuously for 35 minutes to slow it down, slowing at a rate of around 525 metres per second.

It was tight work - if it was even slightly off course, or didn't fire its main engine at the right time or for long enough, it would've missed Jupiter and the entire $1.5 billion mission would have been a failure.

The world waited with bated breath for Juno to send back a tone confirming it had successfully entered orbit.

And when the tone came back, one of the scientists behind the project says it was like Juno was singing to them across the solar system.

Even after the announcement the spacecraft had reached its target, there were anxious minutes spent waiting to see if the solar-powered probe would correctly orient itself to face the Sun.

It was a success, making Juno officially the farthest solar-powered spacecraft from Earth.

Now Juno's work really begins.

The probe's mission will last the next 20 months, feeding back critical information that will help us understand the origin and evolution of Jupiter.

"With Juno, we will investigate the unknowns of Jupiter's massive radiation belts to delve deep into not only the planet's interior, but into how Jupiter was born and how our entire solar system evolved," says NASA administrator Charlie Bolden.

It's Jupiter's radiation that will eventually kill the probe. After its 20-month mission, its electronics will have been fried.

Juno's final act will be a suicide plunge, crash-landing into the planet.

"Early in 2018 the plan is to nosedive it into Jupiter's atmosphere, because they don't want it to possibly contaminate one of the moons that might harbour life underneath a thick ice crust," says space commentator Matthew Pavletich.