The rev 121 Rhea nontargeted flyby is discussed in a different thread - moderator

Mission Description double bill:
http://saturn.jpl.nasa.gov/files/20091102-...description.pdf

Holy smokes, whose job is it going to be to assemble THIS mosaic? Is it you, Jason? Looks gnarly.

It's what I do, shouldn't be too difficult. It is just a clear filter mosaic.

for someone experanced it won't be a problem ,
i am just learnning how to use a control network for isis3


OT) a bit off topic but dose anyone have some links for manuals for isis besides the links here
http://isis.astrogeology.usgs.gov/index.html
https://isis.astrogeology.usgs.gov/IsisSupport/index.php

That's gonna be a great set; lots of terra inexplorata, as it were.

Latest global map of Enceladus was released (pre-flyby):

http://photojournal.jpl.nasa.gov/catalog/PIA11680

and the last pds release " SE_500K_0_0_SIMP.IMG 17-Sep-2009 07:39 99M "
http://pds-imaging.jpl.nasa.gov/data/cassi...02/data/images/

Should we expect images worthy of the swear-jar this around?

This one's not bad for starters:
http://saturn.jpl.nasa.gov/multimedia/imag...4/W00060947.jpg

Wow! That's one hell of a plume!!!

I might have missed it in the mission description, but will Cassini be oriented dish-first along the trajectory during the plume flythrough? Not sure if they feel that any precautions are required or not.

Nope, the mass spectrometer and dust instruments will be facing forward to get the best possible sampling of the plume. We're confident by now that these passages are safe, especially as the speed of this passage is much slower than last time we flew through. The question we're anxious to learn about on this flyby (other than the science results of course) is whether the plume is affecting the spacecraft pointing stability enough to require use of the attitude control thrusters in future similar flybys. If we can get away without thrusters in future close plume flybys, we'll be able to use the flybys to measure gravity and thus investigate the interior structure under the tiger stripes, and we will plan on doing so next Spring, on orbit 131. If we have to continue to use thrusters in the plume we'll use the orbit 131 flyby for more plume sampling instead, because the thrusters interfere with the gravity measurements.

Thanks, John. I suspected as much given the emphasis on direct sampling; appreciate the reassuring confirmation!

I am sure I have missed this class...for when are we expecting the images of the flyby to hit the web?

Next 24 hours I would imagine...

I got this email from the ciclops website:



A select few images will probably appear there first.

The last two pages of JPL's mission description document (a link is found on http://saturn.jpl.nasa.gov/mission/flybys/...ladus20091102/) provide the playback tables for all data acquired during the E7 (today) and E8 (Nov. 21) flybys. When the images (entries with black background, beginning with "ISS" in those tables) get posted on JPL's raw web site is hard to say.

According to the data playback table, the first two observations of Enceladus' plumes at extremely high phase angles (>165 degrees, observable only because the spacecraft was safely hidden from the Sun - in eclipse behind Saturn - at the time they were taken) should already be on the ground.

WOW!

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=205346
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=205345
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=205347
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=205344

Only these four images so far - should soon be a lot more.

Wow is right.

** clink, clink **

Oh my.

...<clink!>

Edit: More on the site as we speak: serious plumage!

Plumes!

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=205381
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=205377
http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=205376

205377 is amazing. I count 5 discrete large plumes; who knows how many smaller ones there may be.

Not sure what this is showing, if anything useful, but here's a string of the plume images (animation).

Versions of a few images without jpeg compression artifacts:

http://ciclops.org/view/5935/Enceladus_Rev...y_Raw_Preview_2

That made a huge difference, Jason, thank you! I'm upping my discrete plume count to no less than 14.

http://saturn.jpl.nasa.gov/photos/raw/rawi...?imageID=205344

Just so you all know, while the image is cropped from apparent data dropouts (which could be recovered during the next playback), you aren't missing much. Maybe another 50-100 lines of surface while the rest is space.

Click to view attachment

RGB combo of Enceladus images (R=IR1; G=Red; B=Blue) with the bright crescent filled in with a lower exposed portion of a RED filtered image (N00145932).

(and lotsa playing around with contrast levels)

Click to view attachment

Good grief!!! What a sight to wake up to! I'm out to work in a few minutes, walking through curtains of lashing rain, and will arrive there soaked to the skin, but I don't care... look at that: a dozen or more plumes on Enceladus... just a magical time to be here isn't it?

Is this Enceladus silhouetted against the rings?

http://saturn.jpl.nasa.gov/multimedia/imag...4/N00145342.jpg

If so, that's a heck of an image, too...

Yes it is, Stu, and looking at it more closely I realize that it's even more interesting than I thought at first glance. Notice the apparent ring refraction around the edges of Enceladus, and the fuzzy dim apparent refraction of 'ringshine' all over the top (assuming that's the south polar region) of the moon.

The plumes seem to sustain a localized atmosphere dense enough to produce these effects. That's wild!!!

I'm confused.

There seems to be no light shining on that hemisphere, so either the sun is directly behind it or it is in eclipse by Saturn. Since they are taking it safe with the camera, surely the sun isn't directly behind Enceladus. And no plumes are visible, suggesting no light is getting anywhere close to Enceladus. So... it's Enceladus in Saturn's shadow? And if so, why is it mixed in with the images from this approach? Enceladus well over the illuminated Saturnian hemisphere at the time of the flyby.

The images in the JPL Raw Images page for this flyby are out of order. Those eclipse shots were actually taken first, then the images with clearly prominent plumes, then the dark frames currently the latest images on that page (taken shortly before C/A), then the few great shots of the south polar terrain boundary, and finally the Tethys images.

WOW!

At work and just had my first chance to look at these.

Enceladus has gorgeous plummage (Bad pun)

A lot of plume detail to be had here.

Beautiful!!!!

Craig

A RGB view with F ring backdrop and one of the saturnlit, small rocks wandering into the scene. Very artifacted stuff, this might be a beauty once calibrated data is available.
Click to view attachment

Looks like it's Prometheus. Cool!

been a long pause… is this all of them or are there surface shots to look forward to for closest approach?

There hopefully will be 1 or 2 more BOTSIMs (NAC/WAC combos) that will come down in this cleanup playback today. Images might show up ~noon MST. So if they don't show up in the next hour or two, that might be it.

Could the pointing have been a little off? - there are 16 NAC/WAC frames from a range of ~11,000km showing just background stars. Perhaps the plume passage exerted some unexpected drag on Cassini?

Those plume shots are spectacular. The level of fine detail is much higher than what I recall from previous Enceladus encounters. Can someone with more knowledge than me comment on this? Is it a consequence of higher resolution? A better viewing angle? Better tracking? Or has the Cassini crew just learned from past encounters how to optimize exposures for the plumes?

Here's an image created from 5 of the raw shots captured this weekend. The 5 images taken through CL1 and 2 filters:
N00145409, N00145408, N00145403, N00145398, and N00145388 were registered then combined in an HDR program to try to bring out some of the structure in the plume, I then colorized the image using a red, blue, and clear filtered image.

Enjoy.Click to view attachment

That is superb. The yellowish saturnshine in particular turns an image into an experience. Thanks for sharing it.

Those look more like cosmic ray hits than stars. Perhaps they were shooting some new calibration frames; in this case, dark exposures.

I think it's because none (or very little) of Enceladus is illuminated, so longer exposures could be used to record the plumes. If it were, blooming from the bright surface of the moon would ruin the faint details in the plume.

volcanopele or other Cassini team members: Can you say anything about how Cassini did flying through the plumes? It seems that thrusters did not bring craft back to proper orientation for BOTSIM images. This would imply that reactions wheels would definitely not be enough to keep craft oriented?

Not sure. Those BOTSIMs were just taken earlier than I thought they would be, though this was expected.

Jason, has anyone set an upper limit on the 'temporary' surface pressure in the south polar region from the localized atmosphere produced from these apparently continuously active plumes? The limb refraction & scattering of F-ring-shine to some degree all around the pole in 145342 really intrigues me.

I'm guessing that the peak surface pressure at the densest point in this region is WAY less than a millibar (probably less than tens of microbars), but the refraction in this image is really striking.

*steps out from the crowd of lurkers*

If the first mystery is how such a small moon could have oceans and emit geysers, the second (for me) is how is the material recycled to replenish the oceans? The returning material gives Enceladus a bright surface color, but then what happens? How does the ice get back under the surface? Is there a related process when the stripes break open?

Thanks, and I love reading the threads here!

Brad

I don't believe there's any noticeable refraction of the ring light in this image- just the plumes near the pole, and an ultra-thin sunlit crescent on the right side of the disk, and a scattering of compression artifacts. Certainly the plume atmosphere is not dense enough to generate significant refraction.

I also don't believe there were any significant pointing anomalies due to the plume passage. There should be an announcement soon about the decision regarding the use of thrusters on orbit 130- I'll check if we're allowed to talk about it here :-)

John

I might be getting spoofed by the curvature of Enceladus' darkened limbs. The refraction I thought I saw (and, frankly, it looks much less pronounced to me now) was a slight distortion of the F-ring right at the point where it disappears behind Enceladus on each side.

May well be a JPEG artifact if it's anything at all besides my imagination; I confess my ignorance of those!