Juno is the second spacecraft designed under NASA’s New Frontiers Program and left Earth on August 8, 2011 for a journey to Jupiter. July 4, 2016 it finally entered Jupiter’s orbit and will now orbit the massive gas giant 37 times in a span of 20 months. Its mission: to collect data on the planetary core, map the magnetic field, and measure the amount of water and ammonia in the atmosphere. That’s the gist of the mission, but here are some little known facts you may not already know.
1) Juno is named after a Roman goddess who could see through clouds. Better known by her Greek name Hera, Juno was Jupiter’s (Zeus’s) wife. According to the Roman myth, Jupiter cast a veil of clouds around himself to conceal his indiscretions; however, Juno was able to peer through Jupiter’s shroud and discern his real character.
2) Juno is actually carrying three passengers on its 1.7 billion-mile trip in the form of three aluminum Lego figures. One is the 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. The little Juno figure is carrying a magnifying glass and Jupiter is holding a lightning bolt. Little Lego Galileo is holding a telescope and a mini-Jupiter in his hands.
3) The Juno mission investment is approximately $1.1 billion in total, which includes spacecraft development, science instruments, launch services, mission operations, science processing and relay support for 74 months.
4) Juno is also carrying a plaque inscribed with some of Galileo’s writings from 1610. This plaque was donated by the Italian Space Agency and replicates a page from Galileo’s notes recording the discovery of Jupiter’s four large moons.
5) Power generation is provided by three solar arrays consisting 11 solar panels and one MAG boom. Two 55 amp-hour lithium-ion batteries provide power when Juno is away from the sun or in an eclipse phase. The power generation system is designed in such a way that it will help in data collection through microwave radiometry or gravity science.
6) Juno plans on ending its mission in 2018 by diving into Jupiter. It won’t be the first spacecraft ending its life this way. The Galileo space probe, which orbited the gas giant between 1995 and 2003, ended its life in a similar fashion. Why would NASA choose to get rid of Juno this way? They want to eliminate the chances of a defunct spacecraft accidentally crashing on one of the Jovian moons and contaminating it with Earthly microbes.
7) The Juno spacecraft has 29 sensors, which feed data to nine onboard instruments namely:
MAG to get an idea of Jupiter’s magnetic field
MWR to provide data on the structure, movement and chemical composition of the planet
Gravity Science to measure Jupiter’s gravitational field and reveal the planet’s internal structure
Waves to investigate Jupiter’s polar space environment
JADE and JEDI to focus on the physics of Jupiter’s intense and impressive northern and southern auroral lights
UVS to take pictures of Jupiter’s auroras in ultraviolet light
JIRAM to study Jupiter’s atmosphere in and around the auroras
JunoCam to generate images for education and public outreach
8) Juno will gaze upon the most immense and intense auroras in the solar system. Jupiter has the strongest magnetic field of all the planets. This makes its polar auroras especially intense and magnificent. They’re so huge that they often span the width equal to several Earths.
9) Juno will hopefully answer the question: does Jupiter have a core? For years, scientists have speculated what may reside at Jupiter’s center. The theories range from a solid, rocky surface to a swirling metallic core of hydrogen. The prevailing theory is that deep within the planet, the hydrogen and helium gases dominating the atmosphere are squeezed into extremely exotic forms–a liquid metal core.
10) Juno will also be hunting for water. It might not seem to be an obvious question, but it’s one that will help scientists understand how, when, and where Jupiter formed. As the largest planet, Jupiter likely formed first, scooping up and collecting whatever ingredients and materials were hanging around the young sun. By measuring how much water Jupiter contains, scientists will be able to learn more about what those ingredients were like, which could resolve a debate about whether Jupiter formed close to its current location or migrated outward as it aged.