The main issue with the encounters is the spacecraft spin and the maximum cadence of imaging. So we can't take images as quickly as we might like, it may take 2-3 spin periods between images. And we have data volume constraints as well. We could use a lot of TDI for nightside imaging, but it frankly hadn't occurred to me to try it, and I'm not sure how well it would work. But this is something we could try for the earlier Io encounters to see if they would be worthwhile for the close ones.

I think what would be cool is an end of mission plunge down the road that flies by Amalthea and gets that image Galileo wasn't able to get.

That would be awesome, but even if orbital dynamics allowed it, how much time is there to transmit data to Earth during such a final plunge? Amalthea is pretty close to the planet, and the PIs of the other instruments would not want the pipeline hogged, I'd bet!


On a related note, I am wondering how EOM disposal will occur; if the main engine still can't be fired, will it be gravitational assists from a moon that push the last perijove down into the clouds (like Cassini's final encounter with Titan? Or will there be an RCS manouevres at apojove?

I also wonder if the SRU camera might be useful here. Judging from its images of Jupiter's nightside illuminated by Ioshine it seems to work well under low light conditions. The SRU's resolution (16.4 deg FOV and 512x512 pixels) is comparable to JunoCam's. Europa plume search might be interesting too but I have no idea if this (or SRU Io imaging at close range) is feasible. However, I noticed that the extended mission description recommends archiving engineering instrument data.

Animation of Io encounters as promised...

https://www.youtube.com/watch?v=xic5OjuhorA

I think the best part will be seeing hotspots and aurorae.

Great animation.

Very nice work. You're definitely better at setting the Cosmographia viewpoint than I am.

You can see from this how these encounters might benefit from a little off-pointing of the spin axis, if this is allowed.

As a public service, you might consider doing animations of the Ganymede and Europa close encounters as well, if you have time.

Animation of the Ganymede flyby:

https://youtu.be/DsPcCRKLP7w

Animation of the Europa flyby:

https://youtu.be/r9bx1GcoqEE

Thankyou!

Im still getting my head around the fact the Ganymede flyby is so close!

P

Great animations.
For Europa I notice that Juno has a nice view of the patch of poorly imaged terrain in the northern hemisphere near longitude 320 degrees, see e.g. time ~2:30 and onwards in the animation. It seems to me that at least in theory, JunoCam should be able to improve the imaging coverage for this area. The problem with this is that apparently it is not possible to image this area if the spacecraft has to be Earth-pointed (it would have to be far from Earth-pointed it seems).

This is almost hard to believe, but if IVO is chosen and both Europa Clipper and JUICE meet their planned schedules, there could be three Jupiter orbiters operating in 2032, each devoted primarily to a different Galilean, and with Callisto itself getting far more than enough close flybys to get a thorough exploration. This is like a long journey through the desert suddenly arriving at a river.

That said, as EC and JUICE are approved, but IVO is as of yet not, I look most forward to the Io data from Juno, and secondarily to any possible Europa plumes search, particularly in the sense that Io and Europa are potentially time-varying, while Ganymede is, notionally, not.

One extremely noteworthy opportunity: The icy shell of Europa is known not to rotate synchronously with respect to Europa's interior, but the baseline in time from Voyager to Galileo was not sufficient, at the given resolution, to give us a first order measurement of the motion which should, in principle, be observable. Just one good image of Europa might suddenly give us that value. The timeline from Voyager 1 to Juno is just about double that of Voyager 1 to Galileo.

Is the Late 2021 Europa encounter still happening?

Alt 88,000km Flyby

I agree, that would be a most amazing period of exploration, although I don't like counting chickens until they are hatched, as they say.

The Jupiter system is still my favorite (sorry, Saturn) in terms of diversity and some of the "big" questions we want answered. I may be very biased here, but then again, so is my avatar image...

The latest information I have on IVO show's it entering Jovian orbit and having it's first Io encounter in August 2033.

Thanks for that, Van. I've seen a few different dates, and if most/all of these missions occur, the timelines could overlap or be a near miss.

To add one more possibility, Trident would enter the jovian system for a gravity assist, so if IVO and Trident were both chosen we would have the possibility of a ludicrous four different missions observing the Galileans at the same time, or in relatively short order!

Timelines for Jovian missions:

JUICE Jovian orbit: Q4/29 - Q2/32
JUICE Ganymede orbit: Q3/32 - Q3/33

Clipper (Falcon Heavy): Q2/30 - Q2/33 (prime mission)

IVO: Q2/33 - Q2/37 (prime mission)

Trident: Q2/32

So Q2/32 could be a busy time in the Jovian System, AND!:


Chinese Gan De orbiter: 2035+ (could be multiple Io flybys or a Callisto orbiter)
Not sure if this is still in the concept stage or is a committed mission. However, it's been talked about for several years, and the Chinese have been good at following through with their plans.

Can anyone confirm if the Europa distant flyby is happening or not later this year?


I'm starting to worry it's not happening anymore because it's not mentioned anywhere except in 1 youtube video talking about the mission extension.

There are no details for any of the encounters Ganymede/Europa/Io or planned science planned for each encounter.
I've tried to google any details and find nothing.

Just chill. What makes you think the broad descriptions of the extended mission linked to upthread are not happening? They are happening. The first Ganymede encounter isn't until June and some of us are a little busy working on other things just at the moment.

The extended mission including the satellite encounters is approved. NASA's managers and the Juno team are negotiating the amount of funding and hence the depth of the science investigations. Per the most recent OPAG meeting about two weeks ago, NASA asked the Juno and InSight teams to propose different levels of funding representing different levels of operational complexity and scientific goals. For both missions, NASA's managers selected the medium level, meaning that not everything that could be done would be done. The ongoing discussions are about which observations will be done (and hence the final level of budget that NASA will provide the mission team).

I wasn't aware of that, my assumption based on reading between the lines on Juno mission extension a few weeks ago was that the high level was approved. I don't have the Juno proposal on hand right now, could you elaborate on what kind of Europa science would be lost with this medium level?

In both the verbal comments during the Juno OPAG update and in the discussions during the OPAG 'town halls' (time periods for questions and open discussion), the medium level of support was brought up. The PI said that in the medium budget level submitted, the funds covered only the planning and navigation necessary for the spacecraft to physically arrive at the encounter locations but not science. HOWEVER, it was made clear by both the PI and NASA's managers that this was the starting point and they were actively negotiation the level of science (and presumably additional funding) that would be performed. No details were provided, which is appropriate given that the discussions were in place.

My takeaway: We aren't likely to get every bit of science from all the encounters with the moons and rings (or probably the Jupiter observations) that would be theoretically possible. However, we will get significant science, presumably the scientifically most important observations. NASA does plan to support adding additional scientists to the mission in part to support the new range of observations.

I'll note that reduced levels of operations and hence scientific observations compared to a theoretical maximum are normal in extended missions. While operations become more efficient with experience, NASA can't keep the operations funding levels at what they were in prime missions. NASA has a budget for all extended missions and needs to spread it across all the missions in that category.

One other tidbit was that the PI stated that there probably could be opportunities to examine the small inner moons if NASA decides to fund the work needed to examine orbital options.

(As a side note for my personal opinion, I suspect that NASA will prioritize the Europa observations highly since they can be used to plan Clipper observations. Io, I suspect, will get the second priority because there are no approved missions to improve observations over Galileo, while Ganymede will get lots of love from JUICE. But all of this is speculation.)

(edited down to closest approaches)



This is fantastic - I didn't realize we were going to get these close approaches!

Is any orbit going to put Juno where it can get a better picture of a small inner moon than ones we already have?

I would assume that the mission wouldn't target one, but there's always the possibility of it flying close to one just by chance.

Not that much of a chance. A 53 day orbit means a little less than 7 perijoves per year. Even multiplied by several years, unless one stretches the definition of 'close', I don't see it happening even in the extended mission, and certainly not enough to resolve Amalthea and co. as anything more than a point.

Cassini got many targets of opportunity because it stayed in the plane shared by the satellites, for many years, as well as the (generally) shorter orbits and much larger resolution on the camera, so the spacecraft didn't need to get particularly close. There were also many more small targets to choose from, of course.

I think you meant Galileo. Cassini flew by Jupiter briefly in 2000.

Agreed, although the orbit period has now been reduced to 43 days.

I ran a search with the reference trajectory a while back, and the best one I found then was an 8-pixel view of Amalthea in July 2025 which may or may not be usable within other constraints.

No, I meant Cassini (referring to flybys of very small irregular satellites). Saturn just has so many more to choose from.

There are still distant observations I believe are planned. There are shown here. https://www.youtube.com/watch?v=hAgLl354PbE...i5&index=15


Ganymede Mid 2021 50,000KM
Europa Mid 2021 88,000KM
Europa Early 2022 47,000KM
Io Mid 2022 85,000KM

Plus more.

Does anyone recognize who processed this image? Was it one of our resident wizards?

https://twitter.com/konstructivizm/status/1...794085103230980

It was posted in another forum, and I'd like to add an appropriate credit.

Looks like a derivative of this PJ06_123 image https://www.missionjuno.swri.edu/junocam/processing?id=1330
which is the work of Gerald Eichstädt and Justin Cowart.

Thanks very much.

With the Galilean flyby's accomplished, eyes will start turning towards whether Juno will get another mission extension next year. Any possible clues on what will happen?

Nice JPL article about recent Europa observations from JunoCam.

What is the limiting factor on operations continuing? It's not radiation damage (which has been much more benign than expected), so it is fuel, or some other system that is reaching the end of life?