Nasa’s Juno spacecraft will make its closest pass of Jupiter on Saturday when it soars over the swirling cloud tops of the solar system’s largest planet at more than 125,000 miles per hour.
The close encounter will be the first time the $1.1bn (£840m) probe has its full suite of cameras and scientific instruments switched on and turned towards the planet as it flies overhead at an altitude of 2,600 miles.
Mission scientists expect the spacecraft to capture the most spectacular images of the planet yet and reveal in unprecedented detail what lies beneath Jupiter’s thick blanket of cloud.
The flyby at 1.51pm BST will be the first opportunity for Juno to get so close to the gas giant since the probe arrived in orbit on 4 July. When the spacecraft reached Jupiter, all of its scientific instruments were shut down to ensure nothing interfered with the crucial braking manoeuvre needed to stop Juno from barrelling past the planet.
The spacecraft is now on a highly elliptical orbit that takes it far away from Jupiter’s dangerous radiation belts before swinging back in and passing close over the north and south poles that flicker with brilliant aurorae more than 1,000 times brighter than those on Earth.
“We are very excited, and really just anxious to see what the poles of Jupiter will look like. No other spacecraft has gotten a good look at them before,” said Candice Hansen, a co-investigator on the Juno mission at the Planetary Science Institute in Tucson, Arizona.
The spacecraft will shoot across the Jovian sky with eight scientific instruments switched on and the probe’s main camera, JunoCam, ready to take snapshots of the atmosphere and poles. The first images from the flyby are expected to be released towards the end of next week. Scientific data from the encounter will take longer to be processed and analysed.
“They will be using JunoCam to take some really high-resolution images of the atmosphere, which promise to be delectable,” said Tom Stallard, an astronomer at Leicester University, home to the UK’s only research team associated with the Juno mission. “We’re all very positive. This is a mission Nasa has planned for a very long time, so this is the fruition of a lot of work.”
The radiation belts that wrap around Jupiter are so intense that Juno’s most essential electronics are encased in a titanium vault. The probe’s sensors and instruments are harder to protect and will take a battering from the hostile rays with every pass around the planet.
“We’ll have some amazing orbits and collect some great data, and then as time goes by it will get more and more difficult, but Jupiter is difficult,” said Stallard.
The spacecraft will perform 35 more flybys during its primary mission, which is due to end in February 2018 when mission controllers command the probe to plunge into the Jovian clouds, never to be seen again.