Mimas and Epimetheus?

http://saturn.jpl.nasa.gov/multimedia/imag...iImageID=129516

Yes, I'm 99.9% certain that is Epimetheus alongside Mimas. The distance between Mimas and Epimetheus at the time this image was taken was approximately 300,000 kilometers.

Very nice image!

It's somehow a relief to know the problem was caused by Earthbound equipment failure....... the Enceladus data is just as lost, but at least it cannot be attributed to the Cassini program in any way. (I had the same initial impulse as everyone else here upon hearing the news......overwhelming urge to slam forehead into keyboard.....especially coming on the heels of last month's Iapetus cosmic ray safing event)

but as others have pointed out, we've been very lucky so far......

It almost seems justified to have some sort of redundant storage onboard the spacecraft to guard against things going wrong on the ground during busy mission phases. Something that could function somewhat like an external backup drive on a PC.......so that if one encounter's data downlink was missed immediately prior to another encounter, the main memory could be dumped to backup and overwritten with new data, and the backup memory could be read at leisure once the DSN problems get resolved on Earth (theoretically you would have at least the entire apoapsis of each orbit to resolve issues and downlink the backed up data).

Of course if redundant storage were included, the pressure would be enormous to just fill said extra storage with more non-redundant observations instead. There are probably a lot of arguments and tradeoffs to be made either way..........but it's heartbreaking to think that there was data that was captured successfully, then erased without ever being seen.

Cassini's SSR-A and SSR-B are already designed to operate sort of like this during mission-critical events (Huygens relay and playback, for example), but for most other flybys, there is nowhere for the data on one of the SSR partitions to go if Earth cannot downlink it promptly. Seems like a glaring lack of redundancy that future missions should address. Since any future outer planet missions well be built around solid state memory that is 10-20 years further advanced then the 1994 era tech which stores Cassini's data, this should not be hard to implement.

WRT the servo heater issue at DSS-63 which caused the problem, it sounds much less severe than the disintegrating main bearing from last fall. The tone of the signifigant events report suggested that the problem came up all of a sudden, but will be (or has been) repaired quickly. Is the a DSN status site that could give more details?

-dave V.

I was looking through the raw image gallery just under a hour ago, and suddenly the Enceladus, Tethys and a lot more of the Dione images have appeared.

The images were not lost after all.

Now THIS is a nice surprise. Is this the "lost" data or only bits that weren't lost?

False color, enhanced view of Dione, cca. 200 000 km:
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Looks like something got splattered across the surface at about 2 o'clock. It's almost got a ray system look to it.
A funky processing to bring out the rays:
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Seems to originate from the relatively fresh and deep crater there.

Some Enceladus images are up on the raw images page. Perhaps the data were still there on the spacecraft when they got another DSN downlink opportunity. Pretty neat.
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Above are the clear filter raw images at and just after closest approach. They are centered on the leading hemisphere near 107W longitude, so I think the bright limb is somewhere near 0 degrees.

Enceladus IR3/GRN/UV3 composite, it looks close to what calibrated colors through these filters look (see this composite):


Enhanced IR3/GRN/UV3 view of Tethys:

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Simulated views of Dione and Enceladus to illustrate the "new" terrain.

A mosaic of Dione from the recent flyby.

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Very nice work everyone!

Curious, why is part of Dione so dark?

You're right Decepticon, it was a little too dark. I think the updated version looks a little better.

Wow, I am in complete shock! This [of Enceladus] is amazing! Can't wait till I get back home from DPS to work on these.

Maybe, not in complete shock. The apparent age is about what I expected [age: South Polar Region <= Leading Hemisphere Planitia < Diyar and Sarandib Plantitia]

*clink* My contribution to the swear jar.

I would scratch the "almost". I think this is a ray system. Dione has about 15% the gravity of the Moon. A modest sized crater should be able to create rays that span a hemisphere.

Great processing on the "lost" data! This is like a mini-Christmas having this all appear so suddenly.

Isn't it the ray system of the crater Creusa, which was discovered on a relatively distant picture taken by Voyager 2 ?
I think it was the only crater ray system discovered by the Voyagers in the Saturnian System, with the exception of Cassandra (also on Dione), which was later shown not to correspond to a crater ray system.
Anyway, I'm happy to see that finally the pictures were not lost.
Marc.

I found the Voyager 2 picture on the Raw Image Data from the Voyager Mission to Saturn provided by Emily at the TPS site:

http://planetary.org/data/voyager/dione/C4399616_GEOMED.png

The ray system is visible if you increase the contrast. Unfortunately, I do not have the tools to do it.
Marc.

This was my atempt at stacking. I'm not sure what I did wrong. (Still learning)

Not much craters on this side of Enceladus.

Here's that Voyager 2 image, not quite so dark.

Phil

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Great !! Thanks Phil.
Marc.

Here is a more natural version of the Voyager view.

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Good one, Ted. When I make a view with a more flattened lighting gradient (high pass filtered) it's because I want uniform tones for mapping. Ted's is much more realistic as a depiction of the surface as seen by the spacecraft.

Phil

I actually do the high pass filtering too, but then combine it with other techniques to preserve low frequency features. As you indicate, it is a difference in purpose. I am simply trying to make pretty pictures.

They're pretty clear in the first false-color vision. In that coloring, they look like yellowish streaks emanating from a deeper yellow patch in the upper right. There is a crater there, but it's not absolutely clear that that's not an accident -- i.e., the crater that can be seen might have impacted by chance about in the middle of whatever earlier event caused the streaking. (To my eye, tracing the rays to a common center actually leads to a point a little to the side of that crater, though of course that could be an illusion.)

One thing about Enceladus that sprang to mind on looking at the latest images is how smooth its limb is. Mimas, and other satellites even larger than Enceladus, show obvious surface features on the limb -- but Enceladus appears to be absolutely flat at any scale where the curvature of the limb is apparent. Enceladus doesn't have a lot of surface gravity, and obviously there is some cratering and other processes going on on its surface -- how does it stay so flat? Even with the resurfacing caused by the plumes, why doesn't something stick up high enough to be noticed on the limb?

I haven't seen any new images on the raw image page since these were posted. Did the webmaster go on vacation?

I'll hazard a guess that all the instruments are powered off during checkout of the new flight software.

I added a couple of Enceladus images from this encounter to my map to help complete the leading hemisphere.

http://laps.noaa.gov/albers/sos/sos.html#ENCELADUS

We now can get a better global idea of the cratering distribution. Smoothest equatorial areas would be near the center of the leading and trailing hemispheres. Are there preferred longitudes of the "precipitation" of snow?

This is a portion of the massive 20-footprint Dione mosaic, work in progress...there seem to be a few frames missing at the eastern limb.

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That's really great! Can't wait to see final result.