It’s no longer news that after a daring five year journey, Juno, the spacecraft launched by NASA finally went into orbit around Jupiter – the largest planet in our solar system.

For the next two years, Juno will orbit round Jupiter as it gathers information that will help scientists understand how Jupiter and other planets were formed. Here are some fun facts about the mission, the spacecraft, and the world it now calls home.

Jupiter’s Four Moons Were First Observed in 1610

Jupiter is surrounded by four large moons, gracefully orbiting it in lockstep. These are the Galilean moons, observed in 1610 by the famous Italian astronomer, Galilei Galileo.

The nearest moon to Jupiter is Io, the most volcanic body in the solar sytem. Then comes Europa, the ice-encrusted moon considered to be capable of hosting life. Next out is Ganymede, the largest moon of them all, which is bigger than the planet Mercury. And last is Callisto.

Juno is Named After a Roman Goddess

Given that this spacecraft will be sorting out what lies beneath Jupiter’s cloud tops, it was aptly named Juno.

Known as Hera to the Greeks, Juno was Jupiter’s (Zeus’) wife in Roman mythology. It was said that Jupiter cast a veil of clouds around himself to conceal his activities – but that Juno was able to peer through this cloud and observe his real character.

Three Aluminium Lego Figures Were Put Aboard Juno

One is these figures is of Italian astronomer Galileo, known for discovering Jupiter’s four large moons. The other two are Juno, the goddess after whom the mission is named, and Jupiter himself.

Lego Juno is carrying a magnifying glass, which signifies her search for the truth. Jupiter is holding a lightning bolt, and Galileo has a telescope and a mini-Jupiter in his hands.

Aboard Juno Is a Plaque inscribed With Some of Galileo’s Writings From 1610

Donated by the Italian Space Agency, the plaque replicates a page from Galileo’s notes recording the discovery of Jupiter’s four large moons. He wrote:

I should disclose and publish to the world the occasion of discovering and observing four Planets, never seen from the beginning of the world up to our own times. I summon all astronomers to apply themselves to examine and determine their periodic times, which it has not been permitted me to achieve up to this day.

These moons wouldn’t be known as Ganymede, Callisto, Io, and Europa for another 250 years, and were not the names proposed by Galileo, who instead called them the Medicean planets after the powerful Medici family. Rather, it was German astronomer, Johannes Kepler who suggested naming the four moons after Jupiter’s collection of lovers.

Juno Is the Most Distant Solar-Powered Explorer

Normally, spacecraft going into the outer solar system carry a radioactive power source, but Juno relies on three enormous solar panels to harvest the sun’s energy. This is possible because Juno’s nine science instruments are extremely energy efficient, and its orbit around Jupiter never takes it through the planet’s shadow, meaning its energy-harvesting solar cells are always facing the sun.

Juno Will Terminate Its Mission By Plunging Into Jupiter in 2018

It won’t be the first spacecraft to die inside Jupiter, the Galileo space probe which orbited the planet between 1995 and 2003 ended its mission in similar manner. But why destroy a spacecraft in such manner?

NASA wants to eliminate the chances of a defunct spacecraft accidentally crashing on one of Jupiter’s moons – namely, Europa – and contaminating it with microbes picked up from earth.

Juno Will Seek To Answer If Jupiter Has a Core

It sounds like a simple question, but it’s not. Scientists don’t know if there’s a solid, rocky core hiding beneath all those beautiful spots and bands on Jupiter’s surface. Existing theories suggest that the deeper one gets beneath the planet’s surface, the greater the pressure of the hydrogen and helium gases that dominate Jupiter’s atmosphere.

It is believed these gases are squeezed tighter and tighter the deeper one goes, which would make the planet have a core made of swirling metallic hydrogen instead of a solid one.

Juno Will Be Hunting For Water                            

This will help scientists understand how, when, and where Jupiter formed—as well as what conditions were like at the birth of the solar system. As the largest planet, it is believed that Jupiter was formed first, even as it swept up and collected whatever special matter were hanging around the sun.

By measuring how much water the planet contains, scientists will be able to learn more about what those matter were like, which would help answer the question about whether Jupiter formed close to its current location or drifted away from the sun as it aged.

Not Every Part of Juno is Expected to Survive Until the End of the Mission

Radiation produced by Jupiter’s intense magnetic field are more than strong enough to destroy the sensitive electronics riding aboard Juno. To slow this down, though not completely eliminate it, engineers encased the spacecraft’s computer in a titanium vault and covered each of its instruments with smaller shields.

Though the spacecraft’s orbit is designed to avoid the most intense bands of radiation, the mission team fully expects the electronics to degrade as the mission goes on. In fact, JunoCam – the orbiting camera on the spacecraft – is only designed to survive seven or eight orbits out of the planned 22 science orbits.

And there you have it, all the scientific facts to inspire you!