Approach Movie (acquisition dates: June 12-29, 2016)

As I write this, Juno is now in the Jupiter Approach phase of its mission. As Juno closes from 16 million kilometers away from Jupiter on June 12 to 5 million kilometers away from Jupiter on June 29, JunoCam will capture color photos covering one entire spacecraft rotation at a rate of 2 to 4 times per hour. During this time, Jupiter will grow from about 13 to about 40 pixels in diameter, but Juno will be seeing it at half-full phase. The wide field of view will encompass the orbits of all of Jupiter's moons out to Callisto, so the main attraction of this movie will be the fun of watching Jupiter's large moons orbiting the planet. The movie is planned to cover 17 days, which one complete Callisto orbit (2.4 Ganymede orbits, 4.8 Europa orbits, and 9.6 Io orbits).

This is a lot of data; even one day's worth of data is more than JunoCam can store in its buffer. All the data will have to be relayed to Earth more than once a day in order to keep making room for new images. If there are any interruptions in data receipt (if, for instance, there is bad weather or an equipment failure at a Deep Space Network station), some frames from the movie may be lost and won't be able to be retransmitted. The Juno team plans to wait for the complete downlink of all of the Approach Movie frames before releasing the images, so don't bother to start looking for it until the day of orbit insertion.

Marble Movie (acquisition dates: July 11-August 26 and August 28-September 23 and September 30-October 18)

Each of Juno's first two elliptical loops around the planet will take 53.5 days to complete. For most of that time, JunoCam will be acquiring about 5 full-color images per hour, watching Jupiter spin from a distance. The planet will appear less than 50 pixels across for the great majority of that time. The movie will run from July 11 to October 18 with two interruptions. The first interruption happens around August 27, during Perijove 1. (JunoCam will be acquiring images then, but not ones timed to continue the movie.) The second interruption happens from September 23 to 30, when Jupiter will be passing through solar conjunction. When spacecraft pass through solar conjunction, controllers on Earth can't reliably communicate with them, so spacecraft are usually put into a lower-activity state to minimize the risk that they'll need intervention from Earth during that period. So JunoCam won't acquire data during conjunction. That period happens to coincide with Juno's apojove on September 23, so Jupiter would appear at its smallest then, anyway. The Marble Movie will end shortly before Perijove 2 (which is on October 19). The Marble Movie will provide the JunoCam team with up-to-date maps of Jupiter. During conjunction, Jupiter is too close to the Sun in the sky for Earth-based astronomers to photograph it, so JunoCam's images will be the only information we can get on Jupiter's atmospheric dynamics throughout this period

Here is how Jupiter's apparent size will vary throughout the Marble Movie. These numbers are for the whole Jupiter disk, but Jupiter will only appear half-full to Juno.

July 11: 47 pixels

July 18: 31 pixels

July 25: 27 pixels

August 1: 26 pixels

August 8: 27 pixels

August 15: 32 pixels

August 22: 48 pixels

August 26: >100 pixels

August 28:

September 4: 41 pixels

September 11: 30 pixels

September 18: 27 pixels

September 25: 26 pixels (conjunction overlaps with apojove)

October 2: 28 pixels

October 9: 34 pixels

October 16: 61 pixels

Perijove 1 (August 26-28)

Because all the science instruments must be turned off for Perijove 0, Perijove 1 will be the first opportunity that they have to operate close to Jupiter. The scientists won't find out how well their instruments work up close to Jupiter until Perijove 1, so this is a really important day for the mission. JunoCam will be commanded to take a wide variety of different types of observations in order to test out its capabilities and different operational modes. It will get polar images of Jupiter with the globe just filling the frame and then do lots of closer imaging of Jupiter, which should show cool cloud features. The orbital path takes Juno close to the terminator -- the boundary between day and night on Jupiter -- so it's possible that tall clouds that poke up vertically might cast shadows that JunoCam could see. JunoCam will try to image the rings, and will also attempt to photograph Ganymede from a distance near 500,000 kilometers. Perijove 1 will be the first time that JunoCam will be able to acquire images more detailed than we can get from Earth.

One-Orbit Movie (October 21-November 2, including Perijove 3)

On Perijove 2 (October 19), Juno will conduct a large Period Reduction Maneuver, a rocket burn that will shorten its elliptical path around Jupiter to one that takes only 14 days to complete. A few days after this maneuver, there will be one final, much smaller rocket burn to clean up any mismatch between Juno's actual and desired science orbits. Once that final burn is safely out of the way, JunoCam will be clear to turn on and take regular photos of Jupiter for its third and final movie. It will acquire frames for this movie through Apojove 2 and Perijove 3, so the "One-Orbit Movie" will be the first movie that will include regular frames during Juno's closest approach to Jupiter. You might also hear the JunoCam team referring to this as the "Zoom Movie," because JunoCam will appear to zoom all the way in to Jupiter, with the planet more than filling the field of view. The JunoCam team may also perform a few more experiments with different kinds of imaging near close approach, the way they did on Perijove 1, but these will be fit among movie frames.

Public-directed targeted imaging (November 3, 2016 until the radiation death of JunoCam or the end of the last science orbit, February 14, 2018)

The images that Juno captures during Perijove 3, combined with images taken by amateur astrophotographers from Earth, will be combined to make a map of Jupiter. Anybody who registers on the JunoCam website can select, discuss, and vote for which spots on this map of Jupiter they would like JunoCam to take images of during the next perijove. Voting for Perijove 4 targets will open on Friday, November 4, and close on Wednesday, November 9. From then on, public voting for JunoCam targets will open every other Friday and close every other Wednesday. Based on the ranking of targets, engineers at Malin Space Science Systems will generate commands for JunoCam to take images covering those targets. (In some cases, two or more targets that are very close to each other might be able to be covered by a single JunoCam image.) Once those commands are written, they are run through a program that estimates the data volume of the resulting images. The final commands will include everything JunoCam can acquire within whatever its data volume limit is for each perijove. The actual number of images that JunoCam will get on each perijove pass depends on their compression ratio -- the more detail there is in an image, the less it can be compressed. There will probably be between 5 and 20 targeted JunoCam images per perijove pass.

Since it's not a science instrument, JunoCam wasn't required to be heavily shielded enough to guarantee its survival throughout the prime science mission. It is shielded, but the Jupiter radiation environment is a nasty one, and JunoCam will suffer radiation damage over time. It was designed to withstand 8 Jupiter orbits, which roughly coincides with the end of 2016. Still, it's more likely to be a slow death (a steady increase in noise) than a sudden failure. We'll probably see degradation of the quality of JunoCam images in 2017, but hopefully the camera will hold up well enough to continue to operate for many more science orbits and voting rounds before Jupiter finally kills the camera. If we're lucky, JunoCam will survive until February 21, 2018, when Juno will plunge into Jupiter, on Perijove 37.

Here's a table of major events to look forward to on the Juno mission.