"Welcome to Jupiter" - NASA's Juno Spacecraft Enters Orbit Around Jupiter

Following a 2.8 billion kilometer inter-planetary journey lasting almost five years, NASA's Juno spacecraft has successfully entered orbit around Jupiter on a bold mission to unlock the secrets of our solar system and its largest planet.

Artists rendering of Juno approaching Jupiter
credit: NASA/JPL-Caltech

Amid rapturous scenes in Juno Mission Control in NASA's Jet Propulsion Laboratory(JPL) in Pasadena, California, Jupiter orbit insertion was confirmed at 11:53 p.m. EDT marking the probe's long-awaited arrival at the gas giant.

Travelling at speeds of 58 kilometers a second(making it the fastest spacecraft to enter orbit around a planet), Juno fired its onboard engine for a risky thirty-five minute burn(insertion maneuver) on time at 11:18 p.m.

“The spacecraft worked perfectly, which is always nice when you’re driving a vehicle with 1.7 billion miles on the odometer,” said Rick Nybakken, Juno project manager from JPL.

The burn occurred at the spacecraft’s closest approach to Jupiter, and slowed it enough to be captured by the giant planet’s gravity into a 53.5-day orbit.

Following an initial capture orbit, Jupiter will begin recording scientific data on its third orbit of the planet by which point the spacecraft will have entered a more stable 14 day-orbit.

Flying from north to south, the spacecraft’s point of closest approach above the cloud tops varies with each flyby -- coming as close as about 2,600 miles (4,200 kilometers) and as far out as 4,900 miles (7,900 kilometers). As Juno exits over the south pole, its orbit carries it far beyond even the orbit of the Jovian moon Callisto.

After the main engine burn, Juno will be in orbit around Jupiter. The spacecraft will spin down from 5 to 2 RPM, turn back toward the sun, and ultimately transmit telemetry via its high-gain antenna.

Over the course of this historic mission Juno will complete thirty-seven orbits over the next twenty months before burning up in Jupiter;s atmosphere to bring the mission to an end in February 2018.

“Independence Day always is something to celebrate, but today we can add to America’s birthday another reason to cheer - Juno is at Jupiter,” said NASA administrator Charlie Bolden.

The main goals of the Juno mission include:

-To find out how much water is in Jupiter's atmosphere, which helps determine which planet formation theory is correct (or if new theories are needed).
-To look deep into Jupiter's atmosphere to measure composition, temperature, cloud motions and other properties.
-To map Jupiter's magnetic and gravity fields, revealing the planet's deep structure
-To explore and study Jupiter's magnetosphere near the planet's poles, especially the auroras – Jupiter's northern and southern lights – providing new insights about how the planet's enormous magnetic force field affects its atmosphere.
-The possible discovery of new Jovian moons.

Juno's view of a half-lit Jupiter and four of its moons before all scientific
instruments were turned off prior to Jupiter Orbit Insertion(JOI) credit: NASA/JPL

                                                                                                                                                One of the main mission objectives is to discover how a giant planet like Jupiter came into being,  and how it evolved. This cloudy world is a primary example of a giant planet, and can also give us  clues as to how other giant gas planets(called "Hot-Jupiters") which we have discovered orbiting  other stars, may have formed.

Juno will accomplish this by studying the planet's cloudy atmosphere and its overall composition. By the end of the mission it is hoped that we will be able to see how Jupiter was born, and how important of a role it played in the formation of other planets in the solar system.

Using the suite of scientific instruments aboard Juno, teams back on Earth will study the magnetosphere of Jupiter, which will tell us if Jupiter has a solid core, and how big or small it might be.

Why the name Juno?
In Greek and Roman mythology, Jupiter was the king of the gods, as well as god of the sky and thunder. Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter's true nature.

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More information on the Juno mission is available at: http://www.nasa.gov/juno

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All You Need to Know About NASA's Juno Spacecraft & What Will We Learn from its Mission to Jupiter?

On August 12 2013, NASA's Juno Spacecraft reached the halfway point on it's journey to Jupiter.
Since launching back in 2011, it has traveled a little over 9.46 Astronomical Units(The distance from the Earth to the Sun is 1 AU), and has performed a series of planetary flybys and deep space maneuvers. In October of this year, Juno will come within 350 miles of Earth's surface. This is known as a gravity assist, or a gravitational slingshot. After Juno says its farewells to planet Earth for the final time, it will race towards the Jovian system before its slated arrival time of 3:29 a.m. UTC, give or take a few minutes!

But before we start asking about what we are expecting to learn from Juno's voyage, let's ask ourselves a few simpler questions about Juno itself..


Why the name Juno?
In Greek and Roman mythology, Jupiter was the king of the gods, as well as god of the sky and thunder. Jupiter drew a veil of clouds around himself to hide his mischief, and his wife, the goddess Juno, was able to peer through the clouds and reveal Jupiter's true nature.


Why does Juno need a gravity assist from Earth?
Well, to put it simply, there just wasn't enough rocket power available to launch a payload of Juno's size directly to Jupiter- over 400 million miles away. Instead, Juno was launched out past the orbit of Mars, before it performed crucial Deep Space Maneuvers to set itself up for October's flyby of Earth. Juno Mission Project Manager Rick Nybakken explains further;

"On Oct. 9, Juno will come within 347 miles (559 kilometers) of Earth. The Earth flyby will give Juno a kick in the pants, boosting its velocity by 16,330 mph (about 7.3 kilometers per second). From there, it's next stop Jupiter... Almost like a second launch for free"!

Confused? Well, think of it this way. If a golfer hits a putt towards the edge of the hole, and the ball does not fall into the cup, instead, hitting the very edge of the hole and "Lipping out", the ball will shoot off in another direction at a faster speed than before. You got the hang of this? Right, let's move on.


When Juno arrives at Jupiter in 2016, it will orbit the gaseous planet for around a year, completing 33 orbits around the planet's poles, using onboard scientific equipment to probe beneath the planet's obscuring yet beautiful clouds.

The main goals of the Juno mission are:

-To find out how much water is in Jupiter's atmosphere, which helps determine which planet formation theory is correct (or if new theories are needed).
-To look deep into Jupiter's atmosphere to measure composition, temperature, cloud motions and other properties.
-To map Jupiter's magnetic and gravity fields, revealing the planet's deep structure
-To explore and study Jupiter's magnetosphere near the planet's poles, especially the auroras – Jupiter's northern and southern lights – providing new insights about how the planet's enormous magnetic force field affects its atmosphere.

Juno's patch to Jupiter
credit: NASA

One of the main mission objectives is to discover how a giant planet like Jupiter came into being, and how it evolved. This cloudy world is a primary example of a giant planet, and can also give us clues as to how other giant gas planets(called "Hot-Jupiters") which we have discovered orbiting other stars, may have formed.

Juno will accomplish this by studying the planet's cloudy atmosphere and its overall composition. By the end of the mission it is hoped that we will be able to see how Jupiter was born, and how important of a role it played in the formation of other planets in the solar system.

Using the suite of scientific instruments aboard Juno, teams back on Earth will study the magnetosphere of Jupiter, which will tell us if Jupiter has a solid core, and how big or small it might be.

End Mission

After completing primary mission objectives and 33 orbits around Jupiter in 2017, Juno will perform a series of de-orbit burns to take the spacecraft out of Jovian orbit and into a destructive re-entry in Jupiter's upper atmosphere.

But first, on October 9th 2013, Juno will return to within 350 miles of Earth to say one last goodbye to planet Earth, before heading to Jupiter to try and unlock some of the secrets of our solar system's biggest planet.