This topic will consist of discussion of Juno operations post-JOI until end of mission, currently anticipated in Feb 2018.
Just under 24 hours after JOI, just inside Ganymede's orbit, on the way out.
I am surprised how far out Juno is going on these two 53 day orbits.
as of right now
http://imgbox.com/OLRvwDkW
This looks more like a projection of the second 53-day orbit, for some time in late August or early September.
Otherwise how to account for the extra red loop?
It looks like the Celestia orbit plans ahead a certain amount of time; in a 2d image these things are a bit tricky to tell. It's also a bit tough to track how far in the background or foreground the irregular moons are from Juno. I don't have the program myself so I can't be sure if there would even be any chance distant encounters.
i put a 120 day period for displaying the orbit
otherwise the WHOLE thing is a RED MESS
the field of view is the default 35 deg.
for the orbit from April 13 to Sept 13
"spk_pre_160413_160913_160613_jm0002.bsp"
basically the best guess at the time as of June 13
in a week or so there will be a update
The best Juno mission public site is: https://www.missionjuno.swri.edu/
The Microwave Radiometer (MWR) turned on Wednesday July 6 and has now received a clear signal from Jupiter, although the planet is unresolved, at a wavelength of 50 cm. Stay tuned for more instruments turning on very soon.
-Glenn Orton, Juno team member
MOD NOTE: Big welcome to Glenn! Have moved his posts to this thread since they provide valuable insight into coming mission ops.
Appreciated! I am also amused by the pull quote from a decade ago... though maybe I shouldn't be because, hey, I'm still following along.
That quote is sure a blast from the past; interesting to see the many changes to the mission architecture (and the constants)! I recall that Bruce was one of the most informed posters on here, but actual science team participation is one step beyond...
Can anyone resolve this inconsistency?
Both the website, wikiedia, and emily's posts say JunoCam's maximum resolution it will achieve of Jupiter is 15 km/pixel
However, JunoCam operation engineer Elsa Jensen says it will be 3 km/pixel in this interview on twitter:
https://twitter.com/NASAJuno/status/750068514560495616
First in orbit image released.
http://www.nasa.gov/image-feature/jpl/junos-post-arrival-view
Oh, the Great (but elusive) Red Spot. For us part time amateur astronomers (work, clouds, weather etc)
our friend is very shy. About 2 months ago, peering through a fellow Society members, nice 10" f5 Newtonian,
it was a case of bullseye.
There it was, just coming into view on the eastern limb. For me, being absent due to the above
factors, it was several years. For others, it was first time or more than 20 years. Has the spot livened up
or was the weather at our deep sky site ideal and the timing spot on. Also, initially I could see only 3 of the
Galilean moons. But one of our young members, accessing SkySafari, said there should be 4. Fair enough,
closer inspection saw Europa in conjunction with Io. Over a matter of half an hour, they slowly drew apart.
Maybe not Juno, but definitely Jupiter, King of the Planets.
There is a higher resolution version here:
http://www.jpl.nasa.gov/spaceimages/images/largesize/PIA20707_hires.jpg
I can't wait till late August to see closer images. I wonder if Jupiter has a polar hexagon like Saturn...
This makes me feeling a mix of happy, curious, excited, and nervous:
https://www.missionjuno.swri.edu/news/juno_sends_first_in-orbit_view:
I'm happy to report that, so far as I know, all instruments on the Juno spacecraft are reported to be healthy.
The mission folks will run a JOI-cleanup orbit-trim maneuver (OTM) on July 13. Its performance will determine if we need a subsequent OTM on July 27, 4 days before apojove. That maneuver is not necessarily required; it depends on how the cleanup OTM goes. If we did well enough with the July 13 cleanup OTM, then the July 27 OTM will be cancelled, and the mission will live with a little bit of discrepancy in the PJ1 longitude and timing (probably just a few seconds and less than a degree of longitude).
Good shooting, Glenn!
Pioneer 10. Trust me!
Phil
https://www.missionjuno.swri.edu/media-gallery/jupiter-approach
Be warned that these all-spin images are large (1648 wide by 128*3*82 high) and mostly black, though the PNG format compresses them reasonably well.
Here's a graphic that describes the processing flow at a very basic level. Note that for the movie we just aligned the images in the three colors, there was no additional geometric processing.
Enjoy!
Those images are great! You can actually see features rotating with Jupiter, easiest the Great Red Spot, but more.
Here crops of processed versions of the lossless images 1586 and 1588:
I'm trying to figure out how best to serve up these data to make them more accessible to people.
To begin with, here is an Excel spreadsheet containing all the information stripped from all the headers.
https://planetary.s3.amazonaws.com/data/juno/approach_metadata.xlsx
I'd like to examine the images one by one to look for cool things like moon shadows on the planet, but it's a little tedious because of the images' great lengths. I thought that as I went through the photos I'd chop out the framelets of most interest, but I can't decide whether to leave the cropped images grayscale or to colorize them according to whether they're the red, green, or blue framelets. Would anyone here use either product if I went to the trouble of posting such crops? See attached for two examples. Each is the same crop from JNCE_2016181_00C1585_V01, containing 6 RGB triplets around the image of Jupiter and its moons. One has been colorized, one not.
Currently, I'm working on overview products like this preliminary one, in this case consisting of 30 roughly processed images (1307 to 1336):
For those who can't wait, http://junocam.pictures/gerald/uploads/20160720/JNCE_2016178_00C1310_V01_1449_proc005-tile.png.
10x reduced:
http://junocam.pictures/gerald/uploads/20160721/ as part 5.
Reduced overviews:
@Gerald....In the pictures that you posted in Post #25, the edge of Jupiter appears to be blue. Gas molecules in atmospheres tend to scatter blue light, so I'm wondering if that is real or if it is an artifact of processing. If it is real, then do you think it would be possible to point Junocam towards the horizon when we get closer to the planet to see if there are any clouds or haze layers visible in the atmosphere?
My understanding is that Junocam rotates with the spacecraft, so it seems like it would be possible to take a picture when the camera sweeps across the edge of the planet.
This https://www.nasa.gov/image-feature/space-station-view-of-noctilucent-clouds gives an idea of what I have in mind. I know that Juno is in a higher orbit than ISS but Jupiter has a larger diameter than earth and the scale height of the atmosphere is higher, so maybe it would work out.
There's also artistic and public relations reasons to do this. The public likes novelty, and this is an angle on Jupiter which has never been seen before.
Another reason to point the camera towards the horizon would be to capture the aurora. That would probably require a fair amount of luck or clever timing, but it might be possible because Jupiter's aurora run continuously. Here is a stunning https://commons.wikimedia.org/wiki/File:ISS-44_Night_Earth_Observation_of_an_Aurora_Australis.jpg.
This https://www.nasa.gov/image-feature/sunset-from-the-international-space-station is gorgeous as well and the viewing geometry enables you to appreciate the vertical structure of the clouds. I think the low sun angle is making the clouds stand out against the background. Junocam is going to have a lot less resolution than this, but maybe Jupiter clouds are bigger.
Here's another https://www.nasa.gov/image-feature/morning-sunglint-over-the-pacific showing the potential of low sun angles.
One more low sun angle picture from ISS. Jupiter has these 'hot spots', which are regions of descending gas which make holes in the cloud layer. The Galileo atmosphere probe fell into one of these. This https://www.nasa.gov/content/space-station-flies-over-super-typhoon-maysak gives a real 3-D sense of a hole in the clouds. I think the low sun angle and oblique view is what makes it work. Trying to time a picture to catch something like this would be hard, but maybe worth a try.
http://junocam.pictures/gerald/uploads/20160722/.
Reduced synopsis:
Although comprising only parts 1 and 5 of the approach movie, I thought, I should share http://junocam.pictures/gerald/uploads/20160723/, simply because they subjectively look exciting to me, and kind of authentic.
One of the two versions (the smaller file) shows the approach sequence similar to the way the EDRs are encoded. This is similar to the scene as it would look like with naked eyes. In the second half features on Jupiter become visible, and satellites look faint.
The other version shows all the noisy background by stretching the images in a logarithmic way without prior background subtraction. Together with the background and compression noise, the satellites are enhanced. But consider the file being large (almost 100 MB). The three lossless images at the end of the sequence look considerably different, since they show much less compression artifacts.
I'm currently rendering parts 2 and 3. Since I'm rendering two versions, both with 10x15 degrees fov, and 120 pixels per degree, i.e. about 4-fold supersampled, it will likely take another day, before the movies will comprise the full approach sequence.
... while rendering part 4 of the approach movie ...
Did you notice the background star (Betelgeuse / Alpha Orionis) moving into the scene?
http://junocam.pictures/gerald/uploads/20160724/.
Edit: Added zip-files (about 800 MB) with the frames used for the animations.
Brilliant - well done!
Phil
Thanks, Phil! It has been an easy exercise compared to your almost daily map updates on Mars.
... In the meanwhile I've composed an http://junocam.pictures/gerald/uploads/20160725/ for download, showing shadows of Io and Europa.
The moons are faint, so you'll need a darkened environment to see them on your computer screen.
Sometimes the moons are invisible while crossing Jupiter's shadow.
Three of the annotated still frames of the AVI:
Gerald,
Very nice work. Question, where does the Blue on top and Red on bottom artifact come from. Strangely, the moon shadow has the blue below the red image what's going on?
@Brian Burns: Thanks! I hope so, too.
I'm simulating the behaviour of the camera as good as I can, and calc back from an output pixel position to pixel positions in the EDRs to obtain color information for the output pixel.
For the sequence I've moved the green channel of Jupiter's centroid to the center of the respective image to obtain alignment along the sequence.
@Floyd: Thank you! My camera simulation is not yet quite perfect; I needed to make a decision between investing more time to narrow down the parameters, or releasing images with imperfect RGB alignment. So I get some RGB misalignment. The apparent exchanged alignment error is essentialy the same misalignment; the difference between the two is dark shadow on bright background vs. bright object on dark background; this causes the observed effect.
My schedule was completing an RMS minimization for the parameters somewhere between end of July and end of August, with end of October as deadline, when the regular science mission begins. But I thought releasing processed images of imperfect quality is better than releasing no processed images. With a delay of several months I may be able to pin down the camera parameters to the best possible within a given family of camera models.
Thanks, well I had almost three years time to experiment with efb01.
For the distant Jupiter image I'm working completely different from an initial intuitive reality regarding the 3d scenario. In this case, it's sufficient instead to assume Juno staying in the center of a hollow sphere with a large radius, and all objects placed on the surface of this sphere.
I've used a by-hand approximation method to find Juno's rotation in terms of interframe delay, essentially a bisection method, working best for swathes where you get Jupiter at the start and at the end of the swath. But since I've used only a very small number of test images, and since there are other uncertain camera parameters, the value isn't optimized over the whole data set.
This approach won't work with Jupiter close-by. Then trajectory and Jupiter's shape and rotation need to be modeled. But with the latter approach the transition between Jupiter's shape and infinity gets somewhat tricky.
Edit: Yes, I see a clear shadow in 1196-1199. I'll post the cropped images later.
Animated gif of 4 images showing Ganymede's shadow on Jupiter:
Still frames:
Sorry for the larger RGB misalignment in these images.
But intersting is image 1196, where Ganymede's shadow is so close to the terminator, that it's highly elliptical.
I'll prepare a graphics which shows the connection to Ganymede.
The annotated image showing Ganymede as source of the shadow:
To find out the limiting magnitude for stars and possibly moons for JunoCam's TDI 4 images, I've stacked (summed two averages of 16 images in this case) 32 log-stretched processed Jupiter Approach images, and stretched the result roughly with a square root function after subtracting some constant bias. The limiting magnitude seems to be near vmag 1.0. Rigel, Betelgeuse, and Aldebaran can reproducibly be processed out. Other stars of Orion or Taurus seem to be invisible or ambiguous at least.
But I hesitated to post the image yesterday as it has been, since there are several properties and features to be explained:
- The image is heavily stretched, and therefore shows much image noise.
- The stars look almost white. In smaller stacks, Betelgeuse and Aldebaran look reddish, as to be expected.
- The vertical stripes are processed compression artifacts.
- Narrow vertical lines, interrupted or not, are mostly summed hot pixels.
- Faint objects appear to induce a darker environment in lossy DCT (compression) blocks.
- Jupiter's Galilean moons average almost away due to their motion. Only their dark compression artifacts remain well-visible in the stacked image.
- There is a horizontal brightish stripe through Jupiter, and extending horizontally across the image. This is likely explainable as subtle lense flare, although I didn't find a documentation about the appearance of JunoCam's lense flare. Near Jupiter, the averaged moons might add some brightness. I cannot disambiguate, whether a ring adds visible brightness.
- There is a vertical brightish feature north and south of Jupiter (south is up). This seems to be independent of the position of the moons, hence cannot be explained away by a lack of dark compression blocks. Thus far, I can't rule out a lossy image compession side effect of Jupiter, lense flare, and some real feature like hot hydrogen. But the latter is no way evident from the image.
moderators - might be good to have a separate thread specific to Junocam image processing?
Mod- Maybe later. For now, Junocam imagery will likely be the main concern of this thread anyhow. Let's see how the mission unfolds.
Thanks, Gerald, for posting all your processed images. I made one of my usual indexes to all the data using your thumbnails. Makes it easy to spot the shadow crossings I was hoping to get a blog entry on this done before leaving for vacation, but it looks like it's probably not going to happen.
https://planetary.s3.amazonaws.com/data/juno/junocam_approach.html
Thanks Emily, for taking this part! You're doing a great job, and you deserve well some vacation.
I'm currently working on a way to improve RGB registering on the basis of improved camera parameters, in order to be ready for delivering the necessary quality, when it's really needed near Jupiter conjunction. Since this implies quite some programming and number crunching, this always takes time.
I took the liberty of colour-balancing Gerald's new image, if that's ok. Jupiter looks so beautiful!
The success of JunoCam outreach depends largely on "the public" providing creative image products. So yes, it's of course welcome to create derived products of my images.
Here an early attempt to enhance Jupiter and its satellites (together with some hot pixels) with one non-https://en.wikipedia.org/wiki/Monotonic_function:
http://junocam.pictures/gerald/uploads/20160801/.
I've removed images 588, 624, 672, 1006, 1185, and 1186, since they caused flickering.
The rendered version of image 1006 is invalid by a cause which is to be investigated. The other five images don't show Jupiter.
You'll barely perceive a color channel misalignment in the AVI. [Obsolete, see edit: Nevertheless, it contains some slightly misaligned images. Seems, that the ratio between angular velocity and interframe delay changed more than once. I'll try to narrow down these subtle changes, before posting the refined still images.]
Edit: Ok, I found the simple cause for the misalignment in some of the still to be published version of the stills: The conversion from BMP to PNG hasn't been completed for the latest parameter adjustment, when I assessed the quality of the PNG stills. The AVI used the BMPs, and should be of acceptable quality. Stills are in preparation for post.
http://junocam.pictures/gerald/uploads/20160801/.
Besides images 1006, and the five black images, rgb channel registering should be better than one raw pixel, now.
Next, I'm intending to quantify the remaining subtle mismatch, and to find a subspace of best parameter settings consistent with the Jupiter Approach images, in order to accelerate the search for the correct parameter settings, once the expected raw perijove images will become available. The latter search initially needs to consider more degrees of freedom, which will be reduced this way.
Juno is on it's way back to Jupiter
http://imgbox.com/uKqMweEV http://imgbox.com/iU0ewcLx http://imgbox.com/4YYh2SsS
If Juno will be passing over the night side of Jupiter during its close approaches, is there a chance it could photograph lightning and aurora on Jupiter? It would also be cool to see close-up photos of the terminator line, aka the sunsets and sunrises in Jupiter's clouds.
Juno's trajectory will likely be suitable to probe Jupiter's aurora from the inside. If a sequence of subsequent JunoCam images will be taken, it might be possible to apply tomography to obtain information about the 3d structure of the aurora in different wavelength bands. http://adsabs.harvard.edu/abs/2012AGUFMSA43C..07B. Being able to add according data from the visible spectrum would be great.
It might also be possible to retrieve additional radiation (flux) data from JunoCam images.
If there are lightnings at the proper instant, JunoCam should be able to see them, but it may require some disambiguation from energetic particle impacts.
The PJ1 images near August 27 will give us a first idea of what's possible.
I have been experimenting with the color in the Juno images by multiplying the green and blue values with correction coefficients >1. Here is the last image (JNCE_2016181_00C1588_V01.png) that shows the GRS without any color correction:
Interesting to see the version that matches the global color spectrum. In this case it looks like the bright zones are yellowish instead of white? What type of data is there for Jupiter's spectrum?
I think the bright Earth clouds would be a better white reference, and matching the color of the sun better that itself is a pretty good approximation of white as seen from space. The moon apparently has a slight color - though I forget which direction it is.
Ah, yes, this could resolve the discrepancy. I've seen material from Earth's moon from less than a meter distance, and it looked perfectly grey. But it likely wasn't directly from the surface. If Moon's surface reddens from space weathering, then it should look reddish, consistent with the appearence of Moon in EFB01, after I've been following your advice to use Earth's clouds as white calibration targets. (One of the (large!) resulting processed EFB12 files http://junocam.pictures/gerald/uploads/20160703/efb_anim_60px000013.html.) However, the color of the clouds aren't quite uniform, so this a compromise.
Since then I've applied the weights (0.74, 0.88, 1.0) for square-root encoded (r,g,b ). Stretching to red=1.0, this would correspond to (1.0, 1.19, 1.35) for square-root encoded (r,g,b ), or to about (1.0, 1.41, 1.83) for linearized (r,g,b ).
The CCD should behave close to linear with exposure time, according to subsection 4.1 of https://www.missionjuno.swri.edu/pub/e/downloads/JunoCam_Junos_Outreach_Camera.pdf:
Quantitative measurements of the structure and velocity of Jupiter's cloud top may require a very accurate calibration of JunoCam's geometry.
However, when going well below one raw pixel alignment accuracy, it's hard to measure inaccuracies visually.
Here seven animated examples, one for each of seven considered camera parameters, with five frames for each of the animated gifs.
You may try to find out in which of the gifs you can perceive a change of color at the limbs, before looking at the graphics below.
Varying the assumption of JunoCam frames per Juno rotation:
Based on images JNCE_2016164_00C196 to JNCE_2016164_00C220, and assuming 80.943 JunoCam frames per Juno rotation,
Brownian K1=-0.00000003839251, K2=2.6E-015, I found
an x/z pinhole scale factor of 1477.939165 +/- 0.275290,
an x-position of the optical axis of 835.665952 +/- 3.204528,
a y-position of the optical axis of 601.001077 +/- 1.892324,
the CCD rotated around the z-axis by 0.002747 +/- 0.000225 radians, (0.157 degrees),
with 1-sigma error bars over the considered data set, or 5-sigma error bars of the means by a sample size of 25, and normal distribution presumed.
The parameters have been optimized for each image individually. The above parameters and errors are mean and standard deviation over the individual images (not the standard deviation of the mean).
The maximum misalignment of the red and green centroid along either x or y relative to the green centroid was -0.032618/120 degree (about 0.01 raw pixels).
The applied model is a spinning pinhole model distorted by a purely radial Brownian model with coefficients K1 and K2, slightly rotated around the optical axis.
Most of the values look credible, but I doubt, that the x-position of the optical axis can be made consistent with EFB images and SPICE trajectory data.
Therefore I think, that some assumption is wrong.
For completeness, I'm intending to modify the three constant parameters, i.e. number of frames per rotation, K1, and K2, as an approach to register the color channels. But I'm skeptical (based on preliminary data), that the misalignments will turn out to be sufficiently sensitive with respect to these parameters to be able to allow for a good value for the x-position of the optical axis, and to stay consistent with EFB images and with laboratory data.
Hence I expect considering a small chromatic aberration as the most promising approach to resolve the misalignments in an overall consistent way.
Parameters for each of the considered images:
JNCE_C196_C220_RGBAlignCSV.txt ( 7.24K )
: 229
An aligned example images (C197) :
Image JNCE_2016164_00C200 is sensitive to the number of JunoCam frames per rotation.
So, I've chosen this image to explore the 3-dimensional subspace of RGB-aligned solutions within the 7-dimensional space of the considered family of camera models, which assume zero chromatic aberration.
This graphics assumes the optical axis at y = 600, and a Brownian K2 = 2.6E-15. It varies the x-position of the optical axis:
To be honest, I'm not really sure what you're trying to do here. IMHO, the small-disc Jupiter images are not great for assessing fine-scale distortions because they don't cover a large area of the field and there's not a straightforward error metric that you can minimize, like residuals in star images would have. Unfortunately we haven't taken RGB star images because of TDI limitations, but maybe we need to look into what we could do along those lines.
Be warned that spin axis knowledge may need to be refined post JOI and PRM burns because of s/c balance changes. There's also some evidence of nutation effects that I have yet to track down.
Mods: I think that this whole discussion should be moved to the "Juno PDS data" subforum, and that subforum be renamed to better reflect a detailed technical discussion of Juno instrument specifics.
Nice to see your updated large Earth view. It is true the cloud colors can vary, especially with lower sun elevation angles and when viewing near the limb. For example it's OK for the clouds right at the terminator to be a bit on the red side. The bright high clouds would be the best reference. For these there are still some effects with atmospheric scattering and absorption, though intensities of various colors should shift by only a few percent.
What is most noticeable to me though is that the ocean areas (including the sun glint) surrounding Chile/Argentina appear to have a greenish cast. I think when color does appear in this situation it would be more orangeish. At the risk of going outside the bounds of this forum, there are lots of videos available showing Earth from various geometries illustrating this that reasonably match the geometry we're seeing with Juno.
Just for fun I made a subjective adjustment to your image that hopefully changes it in the right direction (lowering green by 14% in the GIMP in "shadowed" areas):
juno's location as of now
-- some pretty pictures
http://imgbox.com/3FX11cno http://imgbox.com/PXmo1NYN http://imgbox.com/Emw3MXu9
not much to look at YET
it has been ten days , juno is getting closer in it's orbit
http://imgbox.com/oaej9Prh http://imgbox.com/29YuF3S9
Juno has started imagine correct?
No NASA TV coverage of the first science pass ?
Inside 200k miles now.
Juno's closest approach occurred several hours ago. At https://eyes.nasa.gov/dsn/dsn.html one can see that the Juno downlink is 120 kbps. This is a nice change from the previous Jupiter orbiter (Galileo) .
a repost of mine from a different forum
from 6 am EST to 1pmEST ( ut-4)
http://imgbox.com/Pe4uyRWR http://imgbox.com/8SxhXv5H http://imgbox.com/53wo0nx9 http://imgbox.com/SV5HW6Vo
http://imgbox.com/xvTPUJ5i http://imgbox.com/g397UB3E http://imgbox.com/fFcB8CKZ http://imgbox.com/qqV4e3x1
The flyby was a success!! Jupiter at range of 703,000 km (obtained when Juno was approaching Jupiter), the best view of the polar regions since Pioneer 11:
A roughly linearized version enhances the beauty of the cloud structure:
Lookin' good! But what is that vertical colour banding in NASA's original image, and how did you guys remove it?
Thanks to Emily for the write up, as usual: http://www.planetary.org/blogs/emily-lakdawalla/2016/08271754-junos-first-jupiter-close.html
Very curious to see Jupiter's polar regions and what kind of cloud formations are there. What if we'll find another hexagon?
Saturn's north pole hexagon may be unique.
The current hypothesis says there must be a "steep latitudinal gradient in the speed of the atmospheric winds".
Also: "Polygons do not form at wind boundaries unless the speed differential and viscosity parameters are within certain margins and so are not present at other likely places, such as Saturn's south pole or the poles of Jupiter."
But, I wouldn't mind being surprised.
https://en.wikipedia.org/wiki/Saturn%27s_hexagon
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/-nvePMCOxbew/TXqwuSFdvzI/AAAAAAAAAUw/CNhsEQXwSDU/s1600/postercorrect.jpg
http://www.drewexmachina.com/wp-content/uploads/2016/06/Ted_Stryk_Pioneer_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
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.
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.
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.
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.
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....
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.
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?
Thanks for the insight, Propguy; think it made a few of us breathe easier!
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.
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?
As for the image data, I got a pretty clear answer from Candy Hansen at the press briefing that the way raw image release will work once science data collection begins is that it will happen roughly two days after the return of images, which is the time it takes for navigational data to become available.
I think, for the most part, Juno will not lend itself well to frequent science updates in the way that missions to Saturn, Mars, etc. have.
The deep-looking spectrometers are going to make observations at every (nominal) perijove, and that data – even from the first perijove alone – may do a pretty good job of answering a lot of the science questions. But the big catch is, the team expected to need to calibrate the analysis as the data came in. They're doing something tricky here, trying to determine the composition of Jupiter's deeper atmosphere by looking right through tens of kilometers of Jupiter's upper atmosphere. The team has already stated that they need to learn how to do this as the mission goes on, so the data we already have (?) may answer the questions, but it's going to be a work in progress to interpret that data. (Kepler was very much this way. The data was on the ground long before the analyses really got going. This was an ongoing process during and after the main mission.)
The radio science exploration of Jupiter's gravitational field will probably play out the same way for different reasons. There's no mystery as to what a single perijove's data will tell us, but the fidelity of the measurements will be refined with multiple observations, and 34 is a lot better than 1. I'm sure we'll have the opportunity for decent advances in understanding after, say, 8 or so perijoves, but it might be mere busywork and/or underwhelming PR for the team to keep releasing vague sets of partial results every month. This is a bit like the orbital alpha/neutron spectrometers on orbiters around the Moon, Mars, and Mercury. Some of the data came with each orbit, but they didn't release it in dribs and drabs, but waited until they had a respectable amount of the final data.
The magnetometer may be an exception to this. There may be something interesting seen right away. Who knows?
So, in a nutshell, I think Juno's going to require our patience. The day will come when we have a really nice data set with beautiful advances in our understanding of Jupiter, but it's not going to come in the form of constant wonderful headlines like Cassini gave us at Saturn. It's pretty amazing, and even surprising, that an orbiter is ultimately the type of mission that is giving us data about the depths of Jupiter. And, if one flyby could have done this fairly well, they might have launched a flyby mission and saved a ton of money.
Yes, thanks. I certainly did not mean to imply that I could make heads or tails of the raw data, whether in real time or otherwise. But some occasional commentary about what is being learned from the raw data would be welcome prior to the end of the mission. I'm sure the journals have their own opinions about that, though, along with the means to enforce them.
There have been and will be intermediate updates on conferences and via papers, well before EOM.
Some preliminary results have been presented on the recent press conference, summarized in http://www.nasa.gov/feature/jpl/juno-spacecraft-in-safe-mode-for-latest-jupiter-flyby.
I'd expect raw data of most instruments to be released about one year after they've been taken.
Edit: You might also like to read https://www.britastro.org/node/8092 to learn more about the most recent topic of interest on Jupiter.
Has there been any word from the Juno team at all as to what exactly caused the spacecraft to go into safe mode during Perijove 2? All I've heard is that it was unrelated to the engine anomaly.
There was an issue with JIRAM. That's why it was turned off while they put in a software patch.
http://www.space.com/35043-juno-safe-mode-triggered-by-instrument-glitch.html
Ahh yikes. I guess that also explains why JIRAM wasn't turned on for Perijove 3.
https://www.nasa.gov/press-release/nasa-s-juno-mission-to-remain-in-current-orbit-at-jupiter
Might be some interesting end of mission scenarios with all that extra propellant in a few years.
If the main engine stays inoperable how would Juno be deorbited anyway?
My favourite alternative: raising the perijove to Io orbit for impact. No PP concerns, and checking the resurfacing rate by leaving a crater of known origin, in addition to being the first contact with a Galilean moon. I'm sure a certain Io enthusiast on this board has some thoughts.
A https://twitter.com/lauriecantillo/status/836328935826866182 quotes Scot Bolton (Juno PI) as saying: "We thought we understood Jupiter, but we didn't. It's going to be very different from what we thought."
I didn't find any abstracts related to Juno on today's program, but Bolton did drop some new (to me, at least) tidbits in an interview on Texas Public Radio.
My jaw is dropping over Tom's post about preliminary findings. No indication of a core? Not what I was expecting. So maybe a distributed core? Wow.
A few years back I read some astronomical research papers from the late 1800s. I encountered one debate that had pretty much died out long before any of the books that I'd ever read had been printed. This conundrum about Jupiter (and Saturn) went as follows: Given their densities, they must be made primarily out of hydrogen and helium. But gas compresses exponentially with altitude, so if they're all gas, and they have density like STP anywhere near the top of those atmospheres, the exponential increase in density should make these worlds ridiculously dense – more than metal – over most of their volume. So their observed density doesn't permit a model in which they are made out of those gases – or anything else for that matter.
This thinking was naive, and we've certainly moved past it, but it may turn out that we hadn't latched onto any correct model, either.
I'll note: Solar-sized stars tend to have giant planets with probability proportional to their metallicity, which is a finding that suggested that cores of heavier elements (perhaps mainly oxygen) are important components of giant planets. We can't explore any of those planets up close, but Juno is giving us the answers regarding Jupiter now… or at least a new bunch of puzzling questions.
There are a dozen or more Juno abstracts attached to the program for the Juno sessions at the April EGU ("European Geosciences Union General Assembly") that Gerald linked to just upthread. However, none that I saw is longer than a page, some are only a few sentences, and some really don't contain any substance at all with respect to results.
None of this is surprising. As JRehling (and others) have noted, "http://www.unmannedspaceflight.com/index.php?s=&showtopic=8207&view=findpost&p=233080 There are plenty of good reasons not to release very preliminary figures on paper.
However, I noticed that the http://meetingorganizer.copernicus.org/EGU2017/EGU2017-3926.pdf had more meat to it than many of the others. I was also pleased to discover that the "professional" scientists have included Gerald as one of the JunoCam abstract's authors as an "independent scholar." It's fitting recognition for the amount of work and skill he has invested in working with JunoCam images.
Thanks! I appreciate very much the allowance to collaborate with the Juno team, and the honor to be mentioned as a co-author.
At some point in the mission, after n successful orbital passes, and with enough science data already in the bag, Juno's management team will become less risk-averse and begin to consider taking a chance on re-lighting the main engine. The most obvious choice would simply be to make a delayed shift to 14-day orbits, as originally planned. But those unexpended resources might conceivably be used in other ways too. If the orbital science program were to be completed in the 54-day orbit configuration, what other innovative mission extensions could be considered? For instance, I'm wondering if it would be possible to approach Io or one of the small inner moons without being overcome by radiation. Or, since the probe is designed mainly for deep examination of the planet itself, could the orbit be adjusted to perform one or more close approaches over a pole or over the red spot, again without frying all the instruments?
Just a short mission update. Today Juno does it longest burn to date in orbit (the so called Apojove 22 maneuver). We do an Apojove maneuver most orbits to tweak the Perijove timing and aim point, but this one is quite large to avoid an eclipse of Jupiter. When we entered Jupiter orbit we essentially were at a right angle to the orbit (i.e if Jupiter were at midnight relative to the sun in the orbit Juno is orbiting around Jupiter in a circle around the axis from the sun to Jupiter, passing over the poles to stay in the sun at all times). This is critical in that we never want to go behind Jupiter (very important for a solar powered vehicle). Now that we are 3 plus years from JOI Jupiter has moved 90 degrees in its orbit and will eclipse Juno if no burn is done (~18 hr eclipse, no way to survive that). Thus we are doing a 11 hr burn today on the monoprop thrusters (would have been minutes on the main engine, but that is not an option for use now). No real risk of issues juts a very long day (and night) of operations. It is not a critical single chance burn like JOI was (since we have a secondary and even a tertiary burn planned if needed) but the maneuver itself is critical to proceeding to Perijove 23. For those that really study Juno's orbit yes, we are not at Apojove yet. Doing the burn a little early leaves us less propellant penalty for the later options v.s doing the primary burn right at Apojove. Should be a interesting (but long and boring)evening and night as we watch this occur. Sorry there is not NASA TV feed of this like there was for JOI (would be quite boring actually watching the Doppler plot slowly grow to show progress). I will not be allowed to keep a running status since we in ops are not allowed to provide public status but look for a press release soon on the results.
Very interesting that this eclipse avoidance comes just after the Io eclipse of Jupiter, but it makes sense in that we are in a point of the orbit to view that angle of Io on Jupiter relative to the sun. Go Juno!
Thanks for another fascinating and informative insider's look, Propguy! Best of luck with the burn, and looking forward to a happy press release.
Can't provide specifics but it was a good and uneventful night. Go Juno, ready for Perijove 23.
Thank you propguy. Is there an updated schedule of upcoming perijoves?
Neat release -- the pentagon of storms at the pole has become a hexagon with 6th, still smaller, storm joining the group:
https://www.jpl.nasa.gov/news/news.php?feature=7560
AGU Juno press conference on YouTube at https://www.youtube.com/watch?v=v5_dNPRDzFA
Includes discussion and animation of "shadow jumping" maneuver propguy posted about above.
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