July 6, 2017


The Juno spacecraft was developed by NASA to study Jupiter close up, analysing the planet’s atmospheric composition, deep structure and magnetic field to search for clues about its origin.

JJuno is NASA’s second New Frontiers mission, succeeding New Horizons and preceding OSIRIS-REx. The spacecraft launched on 5 August 2011 and entered Jovian orbit on 5 July 2016. The mission was initially scheduled to end in 2018, but has been extended to 2022 for technical reasons. It will culminate with the spacecraft’s destruction as it plunges into the planet’s atmosphere for a closer look at its composition.

Juno has several special features. The first is that its highly eccentric orbit takes it over Jupiter’s poles with a perijove (its closest point to the planet) very close to the cloud tops (5,000 km). It’s also the first spacecraft capable of venturing so far from the Sun powered only by its solar panels: thanks to its more-efficient photovoltaic cells, it isn’t carrying a radioisotope thermal generator (RTG) previously used for such missions.

Juno is also spin-stabilized, meaning that it uses its own spin (2 rpm) to achieve gyroscopic stabilization.

In addition to its instrument payload, Juno is carrying JunoCam, a camera that has no specific science role but is acquiring remarkable pictures of the planet to engage the public.

As part of Europe’s close involvement in this U.S. mission, CNES helped the IRAP astrophysics and planetology research institute to build the JADE-E electron sensor for the JADE instrument. JADE is designed to detect energetic particles (electrons and ions) produced by Jupiter’s polar auroras, thus complementing Juno’s other instruments to study Jupiter’s magnetosphere.

The JIRAM instrument is another European contribution to the mission, led by Italy. JIRAM is an infrared detector that will probe the deep atmosphere down to 100 km.

Several French research scientists and laboratories are also involved in studying science data from Juno:

  • Michel Blanc at IRAP in Toulouse is Co-Investigator for the Juno mission, focusing specifically on Jupiter’s magnetosphere.
  • Baptiste Cecconi, Pierre Drossart, Thérèse Encrenaz, Thierry Fouchet and Philippe Zarka at the LESIA space and astrophysics instrumentation research laboratory are Co-Investigators on the JIRAM, MWR and Waves instruments.
  • Tristan Guillot at the Côte d’Azur Observatory in Nice is contributing to the study of Jupiter’s deep structure.