August 05 – Launch of Juno (2011)

Juno, in Roman mythology, was the wife of Jupiter, king of the gods.  She was apparently the only one of the immortals able to see through the clouds Jupiter was in the habit of using to conceal his unsavoury activities. This made the name a great choice for the Juno mission, launched August 5th, 2011, as part of the NASA New Frontiers program, to unlock the secrets of the origin and evolution of our largest planetary neighbour.

Artist’s impression of Juno approaching Jupiter (image: NASA / Caltech)

Juno’s mission parameters included measuring the amount of water Jupiter has in it’s atmosphere, mapping the magnetic field, exploring the Jovian aurorae, and peering through the atmosphere to study it’s temperature, composition and movements.

It was a long trip, ending in orbit around Jupiter on July 4th 2016.  Originally in quite a lazy 53 day orbit, this was later shortened to one of 14 days for the primary science collection period.

The first of 36 orbital flybys was performed on August 27th of that year, with Juno skimming a mere 2,600 miles (4,200 km) above the gas giant (trust me – it sounds a long way away, but on Jupiter, that’s skimming).

Highlights of the mission have included

  •   detection  of a changing internal magnetic field (secular variation) which could help our understanding of Jupiter’s, and maybe earth’s, interior structure.
  • new images of volcanic plumes on Jupiter’s moon, Io.
  • Best resolution detection ever of “wave trains” of moving air in the upper atmosphere (these were originally spotted by the Voyager mission) possibly the visible result of some process happening further down in the atmosphere, beyond Juno’s ability to detect.
  • New insights into Jovian lightning, which it turns out is more common towards the poles (unlike Earth, where it tends to be more common nearer the equator).
  • Amazing photographs . . .


Cloud Patterns in Jupiter’s Northern Hemisphere (image: NASA)
The “Great Red Spot” spotted on April 1st, 2018. (image: NASA)
Twighlight at the South Pole, February 7th, 2018. (Image: NASA)


1930  —  Birth of American astronaut, Neil Armstrong.