Juno Spacecraft and Mission

Juno Spacecraft was launched on August 5, 2011, aboard an Atlas V-551 rocket from Cape Canaveral, Florida. It reached Jupiter in July 2016. Since, it has taken stunning pictures of Jupiter’s Great Red Spot and begin to study the planet’s auroras. Juno’s mission goals are to: understand the origin and evolution of Jupiter, look for a solid planetary core, map the magnetic field, measure water and ammonia in deep atmosphere, and observe its auroras.

Juno Spacecraft with human figure for scale and description of science instruments

Among Juno’s scientific instruments are:

  • A gravity/radio science system (Gravity Science)
  • A six-wavelength microwave radiometer for atmospheric sounding and composition (MWR)
  • A vector magnetometer (MAG)
  • Plasma and energetic particle detectors (JADE and JEDI)
  • A radio/plasma wave experiment (Waves)
  • An ultraviolet imager/spectrometer (UVS)
  • An infrared imager/spectrometer (JIRAM)

The spacecraft also carries a color camera, called JunoCam, to provide detailed images of Jupiter.


Juno Spacecraft

Juno was the first solar-powered spacecraft operating at a great distance from the Sun. Jupiter receives 25 times less sunlight than Earth because it orbits at a distance that is five times farther than the Earth from the Sun. Thus the spacecraft’s solar panels were required to generate adequate power for Juno’s instruments. The three solar panels extend to a distance of about 66 feet (20 meters). The greater surface area allows the spacecraft to generate more energy. During each 14-day close-approach orbits to Jupiter, Juno’s instruments only require six hours of full power.


Inner radiation belts of Jupiter


Juno’s orbits had to be carefully planned. Jupiter’s high-radiation belts could seriously damage Juno’s instruments. The spacecraft approaches the giant planet from the poles with enough distance to avoid the planet’s radiation regions. These radiation belts are similar to Earth Van Allen belts but far stronger.

Why Juno

Juno’s name comes from Roman mythology. The god Jupiter drew a curtain of clouds around him to hide his mischief. His wife, goddess Juno was able to see through the clouds and reveal Jupiter’s true nature. Just like the mythology, Juno spacecraft will be able to peer into Jupiter to reveal the planet’s composition and possibly its evolution.


The Mission

Juno is the second spacecraft designed under NASA’s New Frontiers Program but, is the first in many other areas:

  • First space mission to operate a solar-powered spacecraft at Jupiter
  • Farthest solar-powered spacecraft from Earth
  • First space mission to orbit an outer-planet from pole to pole
  • First space mission to fly as close as 2,600 miles to Jupiter’s cloud tops
  • First mission to be designed to operate in the heart of Jupiter’s radiation belts
  • First mission to carry a titanium radiation vault to protect the spacecraft’s most sensitive instruments from a planet’s intense belts of radiation
  • First spacecraft to fly 3D-printed titanium parts (Waveguide brackets)
  • First fastest spacecraft to enter orbit around a planet, at 130,000 mph (129,518mph/57.9 km/s) relative to Earth
  • First to take the highest-resolution images of Jupiter in history

Juno’s Eighth Close Approach to Jupiter image compilation

The Great Red Spot

During July 10 flyby Juno captures stunning images of Jupiter’s Great Red Spot by the JunoCam. As of April 3, 2017, the giant storm measures 10,159 miles (16,350 kilometers) in width making it very close to Earth’s size.

Jupiter's great Red Spot in true color

Jupiter’s Great Red Spot in true color

Spectacular Auroras

Massive amounts of energy swirl around Jupiter’s poles creating the biggest and brightest auroras in our solar system. Electrons are accelerated towards the Jovian atmosphere at energies up to 400,000 electron volts, 10 to 30 times stronger than at Earth. Yet, Jupiter’s brightest auroras are caused by other process scenting are still researching for. These energy particles that cause the aurora are believed to influence the planet’s radiation belts. Understanding these processes get us closer to explaining how planetary physics work.

Juno will continue to operate through July 2018, for a total of 12 science orbits. The team can then propose to extend the mission during the next science review cycle.

With Juno’s research, we will get us closer to understanding how giant gas planets are formed and the role they played in the creation of planetary systems, like our own.

Why with Nye (Ep. 8): Bill Nye Explains How Jupiter is Like a Blender



Resources for Educators:

  1. NASA Jet Propulsion Laboratory Video Playlist for Juno Spacecraft
  2. https://www.jpl.nasa.gov/news/press_kits/juno/pdf/juno-lores.pdf
  3. NASA Juno main page
  4. All about Juno mission, image, and status