Juno Extended Mission, Perijove 34-76 Options

[Bjorn Jonsson]

Animation of the Ganymede flyby:

https://youtu.be/DsPcCRKLP7w

Animation of the Europa flyby:

https://youtu.be/r9bx1GcoqEE

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).

[JRehling]

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.

[Decepticon]

Is the Late 2021 Europa encounter still happening?

Alt 88,000km Flyby

[ugordan]

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.

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...

[vjkane]

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.

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

[JRehling]

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!

[vjkane]

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.

[Decepticon]

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.

[mcaplinger]

I'm starting to worry it's not happening anymore because it's not mentioned anywhere...

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.

[vjkane]

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).

[ugordan]

For both missions, NASA's managers selected the medium level, meaning that not everything that could be done would be done.

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?

[vjkane]

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.)

[owlsyme]

(edited down to closest approaches)

CODE

Satellite Flyby Events
Satellite Time Range vInf Lat W.Lon Phase Alt.
km km/s deg deg deg km
Ganymede 07-JUN-2021 16:56:07 UTC 3676.38 18.427 23.63 55.23 98.2 1045.2
Europa 29-SEP-2022 09:36:04 UTC 1916.98 23.581 -0.84 49.08 130.1 356.2
Io 30-DEC-2023 08:36:10 UTC 3316.44 30.027 63.69 94.23 108.9 1494.8
Io 03-FEB-2024 17:48:50 UTC 3245.51 30.139 -32.67 35.81 143.6 1423.9

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

[Ken Arromdee]

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.

[Explorer1]

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.