Sidestepping between vast bands of radiation and soaring over the gaseous clouds of the solar system’s largest planet at 130,000 mph, the Juno spacecraft reached its targeted spot, orbiting the planet Jupiter.

// READ MORE : The year of the Exoplanet

Juno took five years to travel to Jupiter on a $1.1 billion USB mission, and the final moments of arrival were watched by both NASA and Space fans with anticipation and anxiety.

11:53 PM EST July 5

June signalled it has ended its 35-minute fuel burn designed to slow it down enough to enter into a polar orbit.  Cheers and jubilance erupted from NASA’s Jet Propulsion Laboratory in Pasadena, California, who were overseeing the mission.

“This is the hardest thing NASA has ever done…That’s my claim.”

– Scott Bolton, Juno’s principal investigator

Messages were sent from Juno to JPL confirming each manoeuvre the spacecraft made.  The length of the engine burn was within one second of what JPL had planned.

“We prepared a contingency communications procedure, and guess what?…We don’t need that anymore.”

-Rick Nybakken, Juno’s project manager,

Juno is the second spacecraft ever to orbit around Jupiter: NASA’s Galileo spacecraft spent a full eight years surveying the planet and its system of moons.  Save for a probe dropped into the Gas giants atmosphere, Galileo simply did not have the right tools to peer into what lies beyond Jupiters clouds.  Juno does.

Juno has the tools.

“We have a chance with Juno to go back and study the planet in its own right,”

– James L. Green, Director of planetary science at NASA

Planetary Astronomers believe that Jupiter was the first planet formed in our Solar System.  Many at JPL point at Jupiter as having the secrets to help us understand the origins of our home system.  If Jupiter has a rocky core, and how much water is inside could provide clues into where and how Jupiter formed as well as insight into what came next in the early days of planets.

The Juno Spacecraft is loaded with instruments designed to measure gravitational and magnetic fields surrounding Jupiter.  That could give JPL hints into why, for example, the famous Great Red Spot has been around for centuries.

a Close-up of the largest storm in the Solar System

“Juno is really searching for some hints about our beginnings, how everything started…But these secrets are pretty well guarded by Jupiter.”

– Scott Bolton, Juno’s principal investigator

July 3

Once captured by Jupiter’s gravity on Sunday, Juno began to accelerate faster towards the planet, passing inside the orbits of Ganymede and Callisto, two of Jupiter’s largest moons. By Monday is whipped past Io and Europa.

The spacecraft has been on autopilot since early Thursday, performing moves in a pre-programmed sequence.

“To know we can all go to bed tonight, not worrying about what’s going to happen tomorrow, it’s pretty awesome,”

-Diane Brown, the program executive for Juno at NASA headquarters,

10:30 PM EST July 4

Juno skimmed over Jupiter’s North Pole, through a belt of radiation moving at almost the speed of light.  This was one of the most dangerous times for the spacecraft: the radiation could easily knock out electronics, instruments, and even computers onboard the spacecraft.

“They will go right through a spacecraft and strip the atoms apart inside your electronics and fry your brain if you don’t do anything about it,”

– Dr. Heidi Becker, Radiation Monitoring Team

Juno was built to withstand such pressures, and its titanium shielding proved up to the challenge.

jupiter aurora_feat
Jupiter’s Polar region is subject to some extreme conditions

11:18 PM EST July 4

Juno’s main engines began firing, in an attempt to slow the spacecraft down just enough to still be caught by Jupiter’s gravity.  Juno’s handlers at JPL had picked their entry through Jupiter’s diaphanous rings carefully, ensuring the way was clear of debris.  However, no one can ever be certain.  Even a speck of dust hitting a spacecraft at 130,000 mph can cause serious damage.

Juno travelled with 2,9000 miles of Jupiters cloud tops, hitting the exact spot the team had picked for its 1.7-billion mile trip.  Juno then moved away, further from Jupiter.  After the engines had finished burning, the spacecraft pivoted, spun on its own axis and pointed its pivotal solar panels towards the Sun.  Sunlight at Jupiter is a meagre 1/25th as bright as it is here on Earth, and Juno, equipped with 30 foot long panels, will only be able to generate 500 watts per hour.

“Now the fun begins, with science,”

– Scott Bolton, Juno’s principal investigator

Juno’s Orbit around Jupiter


Juno is currently on a 53-day orbit.  It’s scientific instruments, having been turned off until arrival, will turn back on July 7th.  On August 27th, Juno will begin to swing back to get it’s – and our – first close-up look at Jupiter.  Juno will first its engines yet again on October 18th to move into a 14-day Orbit, and thats when the Science really begins.

Juno will make multiple flybys before researchers are able to answer questions about its core.  With a different vantage point in a polar orbit, Juno is expected to add to the number of known Jovian moons, currently at 67.  Radiation will hit Juno each time it swings past Jupiter, and that will take its toll on the spacecraft and its electronics.  As the mission goes on, and the orientation of each orbit pivots, Juno will pass through stronger and stronger belts of radiation.

February 20, 2018

Completing its 37th orbit around Jupiter, Juno will make a headfirst dive into the planet, ending the mission, much in the same way Galileo ended its mission in 2003.  This method is of pivotal importance, ensuring no possibility that Juno can crash in the moon of Europa, widely regarded to have liquid water under its icy exterior, and considered one of the likeliest places for life in our Solar System.  Crashing into the moon could contaminate it with microbes that have hitched a ride all the way from Earth.

While it seems a cruel end for a spacecraft that could give us so much insight, perhaps it is fitting.  Even the smallest microbe could contaminate a candidate for life, so the mission will end inside the largest planet in our solar system.

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