Other Satellites On Tc Options

[tedstryk]

Other than the Iapetus encounter, I noticed that flybys of Mimas (108,000 km), Enceladus (189,000 km), and Rhea (153,500km) are mentioned. Is anything planned for these flybys? I would normally just assume no, given their proximity to the Huygens mission (they are all on the 16th). But considering the Ta and Tc information sheets didn't mention the Tethys non-targeted flyby on Ta, I am surprised that they are mentioned at all. Given this, is any imaging planned?

Ted

[volcanopele]

The one I know for sure about is Rhea, where we should get a good view of its giant ray crater (rays are giant, the crater itself maybe fairly small)

[tedstryk]

Great to hear. Will this include any of the wispy terrain?

[Bjorn Jonsson]

The one I know for sure about is Rhea, where we should get a good view of its giant ray crater (rays are giant, the crater itself maybe fairly small)

Do you know the approximate latitude and longitude of that crater ? I don't see it in Voyager-derived maps of Rhea (or maybe it's not obvious there), yet most of the areas in view in mid-January were rather well imaged by Voyager 1.

[Decepticon]

The one I know for sure about is Rhea, where we should get a good view of its giant ray crater (rays are giant, the crater itself maybe fairly small)

Do you know the approximate latitude and longitude of that crater ? I don't see it in Voyager-derived maps of Rhea (or maybe it's not obvious there), yet most of the areas in view in mid-January were rather well imaged by Voyager 1.

Top Left bottom image Bjorn. http://astrogeology.usgs.gov/Projects/Satu...s/rhea_full.jpg



And link to site where this map was found.
http://astrogeology.usgs.gov/Projects/SaturnSatellites/

[Decepticon]

Another great link with the orginal voyager image with that crater.

http://planetary.org/saturn/rhea.html

[volcanopele]

Wasn 't sure if it was in the Voyager images, nor do I remember the lat and lon of the ray crater. I was just told that the images taken in January will show that ray crater.

[Bjorn Jonsson]

I managed to figure this out myself. North seems to be roughly up in this image:

http://ciclops.lpl.arizona.edu/view.php?id=506

Assuming this I made the attached preliminary cylindrical map by adding the Cassini data to areas of lower resolution Voyager coverage. I only very crudely corrected for varying illumination. The big crater at upper left is visible in exactly the same location (but at lower resolution) in the Voyager based map so this map seems to be correct. Longitude 0 is at the center of the map. The next step is to render this thing to see what Cassini will image...

Attached thumbnail(s)

 

[Decepticon]

^Amazing!

Have you had time to do the same to dione using the recent images?

[Decepticon]

Interesting...

Spacecraft time (UTC) Ground time (UTC) Event
Jan 16
06:08  Jan 16
07:15  Cassini flies by Mimas
The flyby will be at a distance of 108,000 kilometers (67,000 miles) and a speed of 1.3 kilometers per second (2,900 miles per hour). This is just a little bit closer than Voyager 1 ever got.
06:16 07:23 Cassini flies by Enceladus
The flyby will be at a distance of 189,000 kilometers (117,000 miles) and a speed of 10.2 kilometers per second (22,800 miles per hour). Voyager 2 got 50% closer than that, but with the difference in quality between Cassini''s and Voyager's cameras, the Cassini images will be more informative.
06:26 07:33 Saturn Periapsis
At a distance of 4.8 Saturn radii from the planet (or 290,000 kilometers, or about 180,000 miles), this is just outside the orbit of Enceladus. 
11:58 13:05 Descending ring plane crossing
At a distance of 5.9 Saturn radii from the planet (or 360,000 kilometers, or about 220,000 miles), this is outside Enceladus' orbit, inside the E ring. Particles in the E ring are too small to be hazardous to Cassini.
15:51 16:58 Cassini flies by Rhea
The flyby will be at a distance of 153,500 kilometers (95,400 miles) and a speed of 5.1 kilometers per second (11,400 miles per hour). Voyager 1 got two times closer than that, but with the difference in quality between Cassini''s and Voyager's cameras, the Cassini images will be more informative.

From here bottom of page... http://www.planetary.org/news/2005/huygens...eline_0110.html

[tedstryk]

I hope this means they are doing imaging.

06:16 07:23 Cassini flies by Enceladus
The flyby will be at a distance of 189,000 kilometers (117,000 miles) and a speed of 10.2 kilometers per second (22,800 miles per hour). Voyager 2 got 50% closer than that, but with the difference in quality between Cassini''s and Voyager's cameras, the Cassini images will be more informative.

Not to mention that at Voyager's closest approach the scan platform was stuck and it didn't do any imaging at all!

I have noticed that there have been no raw images since those taken January 1. Is this due to the Titan encounter. I know it was going to stop at some point, but I didn't think it was that far out.

[volcanopele]

I hope this means they are doing imaging.

06:16 07:23 Cassini flies by Enceladus
The flyby will be at a distance of 189,000 kilometers (117,000 miles) and a speed of 10.2 kilometers per second (22,800 miles per hour). Voyager 2 got 50% closer than that, but with the difference in quality between Cassini''s and Voyager's cameras, the Cassini images will be more informative.

Not to mention that at Voyager's closest approach the scan platform was stuck and it didn't do any imaging at all!

I have noticed that there have been no raw images since those taken January 1.  Is this due to the Titan encounter.  I know it was going to stop at some point, but I didn't think it was that far out.

I just took a look at the imaging plans for Tc, and yes, Mimas, Enceladus, and Rhea observations are planned to compliment the Iapetus, Tethys, Dione, and Phoebe coverage we have already.

[pioneer]

Mimas, Enceladus, and Rhea observations are planned to compliment the Iapetus, Tethys, Dione, and Phoebe coverage we have already.

Phoebe? What observations can we get from such a large distance we didn't get from the June flyby?

[volcanopele]

Mimas, Enceladus, and Rhea observations are planned to compliment the Iapetus, Tethys, Dione, and Phoebe coverage we have already.

Phoebe? What observations can we get from such a large distance we didn't get from the June flyby?

I meant that we already have regional scale (and in the case of Phoebe, local scale) coverage of Dione, Phoebe, Iapetus, and Tethys, and coverage in Tc will give us Enceladus, Mimas, and Rhea.

Looking at the Enceladus coverage, looks like it will be a gap fill in the leading hemisphere. Not as good as Voyager's best coverage, but it is much better than what we have of that region.

[tedstryk]

Why has no imagery from Jan 1 to Jan 6 when they turned the instruments off been posted?

Ted