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Headshot of Emily Lakdawalla

Juno has arrived!

Posted by Emily Lakdawalla

05-07-2016 1:14 CDT

Topics: Jupiter's moons, Io, Europa, Ganymede, mission status, Callisto, Juno, Jupiter

For a second time, NASA has placed a spacecraft into orbit at Jupiter. The spacecraft operated exactly according to plan, and Juno successfully entered orbit at 02:50 today, July 5, 2016, UTC; a further 15 minutes of engine firing beyond that placed Juno into its desired orbit. The actual burn time of 2102 seconds was only 1 second off of the predicted value.

As of the moment I'm writing this, they hadn't yet downlinked telemetry (or if they did, they haven't told the media); they only received tones from the spacecraft's low- and medium-gain antennae that give the most basic information on spacecraft health. But so far, so good, for everything, and it was a pretty euphoric team at the post-orbit-insertion briefing.

Below is the JunoCam approach movie, 17 days and about 1500 images covering an entire Callisto orbit. There is a soundtrack (by Vangelis), so mute your computer if you're at work before you play it! I'm told there will be a version without all the extra produced padding posted at some point this evening, but it's getting late and I have to drive home...

There are several things to notice in this video. You can see Io, Europa, and Ganymede turning off and back on again as they pass into Jupiter's shadow. You can see belts and zones begin to come into focus as Juno approaches. Sometimes, if you squint, you can spot the red spot. You can see Jupiter's belts fall to a steeper angle as Juno begins to rise in latitude. Some of the moons, especially Callisto, look kind of blinky -- this has to do with the way that the JunoCam instrument works. It's designed for extended targets (things that fill many pixels), not point targets. Scott Bolton said on the press panel this evening that at this phase angle, Callisto was dimmer than predicted. Its dim light, combined with the sharpness of the JunoCam optics, meant that its light was focused into a very small area on the detector. On the JunoCam detector, not all of the area is active, meaning that photons can fall in between pixels, or at least in between areas where they would be detected. When Callisto's light fell into those areas, it seemed to dim in the movie.

Juno principal investigator Scott Bolton was repeatedly asked about plans to release the raw images. During the morning press briefing he said that their release "depends on what we see [in them] and how interesting it is," but by the evening he was saying that the mission intends to release them within a few weeks, though he wasn't specific as to the timeline, citing "technical issues." You can bet I'll keep asking!

See other posts from July 2016


Or read more blog entries about: Jupiter's moons, Io, Europa, Ganymede, mission status, Callisto, Juno, Jupiter


Martin Hajovsky: 07/05/2016 01:32 CDT

Thanks so much for all you do Emily. Your coverage was priceless as usual.

sepiae: 07/05/2016 02:21 CDT

Yes, thank you from here as well. It's extremely helpful. So, yet another marvel of engineering-magic that shows the better of our species. And now it's bracing ourselves for new rushes, including emotional ones, the kind that came with Chury, Pluto, the entire Cassini mission... ... ... A redemption for the phrase, 'have you heard the good news...?' They're found on pages like these, after one got depressed from world news. 'The spacecraft worked perfectly, which is always nice when you're driving a vehicle with 1.7 billion miles on the odometer.' - Rick Nybakken

battling: 07/05/2016 11:09 CDT

Have not submitted to news media, we must wait, ?????. Hmm we are members and you are telling us that interesting news must be publiished before we members can be informed????. REF. Jupitor arrival

Joshaeus: 07/05/2016 05:25 CDT

Congrats! Call me naive, addition to its primary assignment of studying Jupiter itself, will Juno be doing any useful science on the Galilean satellites? Any way to determine an estimate if when they formed? (Considering Saturn and Neptune's comparitively young moon systems, I think I have good reason to question whether either Jupiter or Uranus's moon systems are remotely primordial)

SpaceFan1234: 07/06/2016 02:57 CDT

Pretty much a miracle given that the MSA Mgr is the same person who led two failed Mars missions, the Mars Climate Orbiter, (remember the unit error?) the Mars Polar Lander (never heard from after landing) as well as Genesis which crashed into the Utah desert upon it's return.

Messy: 07/06/2016 06:53 CDT

Joshaeus, if you check out Today's New York Times, you will notice the following paragraph: With a different vantage on a polar orbit, the spacecraft’s cameras are likely to add to the number of Jupiter’s known moons, now 67. Of the 63 NON-Galilean moons, we have close-up photos of three of them.

davidkoren: 07/07/2016 08:24 CDT

Another uplifting human adventure! As a Physics/Astronomy student I chose to investigate obscure Callisto, because others were infatuated with Io and Europa. It was fascinating, and I hope we learn more about it even as we explorer Jupiter. Emily, I enjoy your writing and your image analysis.

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