Juno at Jupiter, mission events as they unfold Options

[Ian R]

Let's not forget that Pioneer 11 got our first half-decent look at Jupiter's north pole, and it didn't spy anything hexagonal.

https://lh5.googleusercontent.com/-nvePMCOx...stercorrect.jpg

http://www.drewexmachina.com/wp-content/up...r_11_npf1cf.jpg

-- [Tip of the cap to UMSF's very own Ted Stryk]

Nonetheless, this recent Juno image release is just a taster of the really good sauce that's yet to come

[JRehling]

Keep in mind that Jupiter's cloud deck is very deep, and whatever we see from space looking down is just one layer. My understanding is that the jovian poles show us a layer of haze that overlies the cloud layer that we see elsewhere. So, we're not merely looking at the ammonia clouds we see at other latitudes and seeing how they vary with latitude – we're seeing a different layer altogether.

https://www.eso.org/public/usa/images/eso0123e/

So, we may very well not have a chance to see whatever Jupiter has at an altitude comparable to Saturn's hexagon, so long as we look in visible light. This recapitulates the reasons why Juno isn't just a "pretty pictures" mission and why JunoCam is a ride-along instrument while other instruments do the real science.

It's a pretty good bet that Jupiter has some different-looking maps at different depths and Juno will give us a peek at that, but JunoCam will not.

The thing I'd like to know is whether Jupiter's banding is upper layers only, or "bands all the way down," or "cylinders all the way down." I'm not sure how much we'll find out as Juno's mission proceeds or if we'll get a bonanza of results released all at once when the whole mission is done. The microwave spectrometry is going to take some time to process and interpret, and the gravity / radio science is going to accumulate over time.

[antipode]

Let's not forget that Pioneer 11 got our first half-decent look at Jupiter's north pole, and it didn't spy anything hexagonal.

True, but I'm more interested in the presence of a polar cyclone like Saturn - that might well have been small enough to have eluded the Pioneer imaging.

P

[nprev]

Worth remembering that Jupiter only has an axial inclination of 3 deg (vs. a bit less than 27 deg for Saturn), so the illumination angle is always gonna be very low.

[Bjorn Jonsson]

I doubt there is a hexagon at Jupiter's poles. Any hexagon there would probably have to be much smaller than on Saturn, otherwise it would show up as an 'irregular/wavy' cloud band in simple cylindrical maps of Jupiter (and as a hexagon if the map is rendered from above/below the pole). At least this is the case for Saturn.

[mcaplinger]

https://www.missionjuno.swri.edu/news/next-jupiter-pass

"Mission managers for NASA’s Juno mission to Jupiter have decided to postpone the upcoming burn of its main rocket motor originally scheduled for Oct. 19."

Some scrambling here today to generate an imaging sequence for the PJ2 pass.

[Explorer1]

Better safe than sorry, of course! And on the bright side, it gives Juno more time away from the radiation belts, which is probably good for the final lifespan....

[tanjent]

In some respects the issues faced by the mission managers are reminiscent of Akatsuki's situation. The article's wording suggests that the one-orbit postponement of PRM is a minimum, and that the managers may conclude that it is better to continue in the longer-duration orbit indefinitely than to risk losing the mission to an engine malfunction. In that case it would take almost four times longer than planned to complete the desired number of passes. Those higher-apojove orbits might reduce the radiation exposure somewhat by speeding through the danger zone a little bit quicker, but other forms of wear-and-tear could then take on added importance.

[mcaplinger]

And on the bright side, it gives Juno more time away from the radiation belts, which is probably good for the final lifespan....

There's very minimal science possible away from perijove, so a longer lifespan has no real value on its own.

[B Bernatchez]

Would there be any problem with pressurizing the system a couple of days ahead of time before the PRM? Could the system hold pressurization that long?

Propguy, are you still here?

[propguy]

Would there be any problem with pressurizing the system a couple of days ahead of time before the PRM? Could the system hold pressurization that long?

Propguy, are you still here?

Yes I am still here. I really can't talk much about what has happened other than what was put in the press release. We do pressurize up the system ahead of the burn (in fact since DSM1 it really is a re-pressurization bring the tanks up only 10 psi or so). We had done this same approach for DSM1 and JOI (we left the system open to the pressurization system between DSM1 and DSM2 since they were only 15 days apart, the rest of the time there are pyro isolation valves we use to keep propellant vapors from diffusing into the gas side components and creating issues). When we did the valve firing and pressurization last week two of the check valves stuck closed for a few minutes and then opened. The issue is if the check valves for one propellant tank were to stick close during the burn it would drive the main engine operating conditions outside of the qualified limits and could cause engine failure. Thus to be safe the program deiced to skip PRM this perijove and we are now looking at lots of options for doing a burn on a subsequent perijove. This is a concern but not something that will keep the program from achieving a proper and final science orbit. Sorry I can't say much else since nothing is decided yet. S/C now has generic science sequences loaded and running (i..e gathers science but no specific targeting sequences on board to view any given element or feature) so this becomes a science pass instead.

[nprev]

Thanks for the insight, Propguy; think it made a few of us breathe easier!

[peter59]

NASA’s Juno spacecraft entered safe mode Tuesday, Oct. 18 at about 10:47 p.m. PDT (Oct. 19 at 1:47 a.m. EDT). Early indications are a software performance monitor induced a reboot of the spacecraft’s onboard computer. The spacecraft acted as expected during the transition into safe mode, restarted successfully and is healthy. High-rate data has been restored and the spacecraft is conducting flight software diagnostics. All instruments are off and the planned science data collection for today’s close flyby of Jupiter (perijove 2), did not occur.

[tanjent]

Along with many other space enthusiasts with limited time and attention, I tend to curb my fascination until missions are on station and ready to produce science data. Juno has recently come very close to reaching this status and I am just one of many now feeling a great eagerness to peel Jupiter like an onion and find out what's inside.

The two recent anomalies, even though apparently unconnected, still remind us that no space mission is easy and that alterations of the nominal plan are part of the game. If so, the only option is plenty of patience by the mission team and even more by those of us looking over their shoulders. We have to hope that that the cause of the problems, and some low-risk remedial measures, will become clear during the 54-day cruise out to apojove and back. It will be a relief if the spacecraft enters its planned science orbit, but if the engine problem is not fully understood and they can get the same data from a longer stay in the present orbit, then of course that risk-avoidant option looks pretty attractive.

But because I just can't help myself, I am curious to know if any of the non-photographic science data will be made public in real time, before the end of the mission and the crop of articles that will follow. I can very well understand why this might not be the case. If it takes longer than expected to assemble the full dataset, can we look forward to any interim hints about what is being learned?

[mcaplinger]

But because I just can't help myself, I am curious to know if any of the non-photographic science data will be made public in real time... can we look forward to any interim hints about what is being learned?

I know of no plans to release any science data "in real time". I would expect that as is always done, at regular intervals and if anything interesting is learned, there would be a press briefing or press release, just like there was a couple of days ago.