Juno’s second perijove – may the science commence!

The Juno spacecraft is today 3 million km from Jupiter, and it has spent its time in the first of two capture orbits about the planet. These orbits take 53 days to complete and are followed by the main science phase with orbits about 14 days long. The capture orbit itself is designed to keep the time that the main engine is lit as short as possible – and using as little fuel as possible – whilst still enabling the probe to enter orbit at Jupiter.

At the end for this first capture orbit, on the 27th of August 2016, Juno will be preforming its second close swing-by of the planet – the first was during orbit insertion on the 4th of July – and this time all the instruments will be gathering data, providing us with the very first close-up observations. The closest approach, known as a perijove (or PJ, for short), will provide the closest measurements ever to Jupiter, and observations of its atmosphere and magnetic field will sample regions that have never been seen before. Such observations, to be taken over the next year or so, will provide answers to fundamental questions about Jupiter and the formation of our solar system. 

After this intense period of gathering observations, the spacecraft will beam back the data to Earth in the days that follow PJ 1, and it is only then that colleagues will begin to analyse this new and exciting data.

In the hours after Jupiter Orbit Insertion (JOI) on the 4th of July, the instruments were turned on, and JunoCam, the camera on-board the spacecraft, started imaging Jupiter every 14 minutes, using a range of filters so that a composite colour image could be reconstructed, and by stringing a number of images together, a movie could be made. The movie below was made by Gerald Eichstädt, and shows Jupiter receding in the sky after JOI, with Juno being firmly captured by Jupiter’s immense gravitational field. 

These images are freely available to anyone, and with Juno making a close approach to Jupiter on August the 27th, make sure to check back for some amazing views of Jupiter! The data that the other instruments gather will also be freely available for anyone to download one year after the observation was taken.