Cassini/Huygens Mission Update Thread

[Leovinus]

<i>Cassini sighted the far-off icy moon Tethys as it headed back toward Saturn in its long, looping first orbit of the planet. A faint hint of detail on the moon's cratered surface is visible here. Tethys was discovered by Giovanni Cassini, for whom the spacecraft was named. Its diameter is 1,060 kilometers (659 miles) across.<br /><br />The image was taken in visible light with the Cassini spacecraft narrow angle camera on Sept. 9, 2004, at a distance of 8.8 million kilometers (5.5 million miles) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 81 degrees. The image scale is 53 kilometers (33 miles) per pixel. The image was magnified by a factor of four and contrast enhanced to aid visibility. </i> <div class="Discussion_UserSignature"> </div>

 

[chew_on_this]

Thanks for the update!

 

[jimblewit]

This is a recent JPL pic that's really pretty:<br /><br />http://photojournal.jpl.nasa.gov/jpeg/PIA06491.jpg<br /><br /><i>This Cassini image shows mesmerizing detail in the swirls and ribbons of air in Saturn's atmosphere. The view was obtained at a distance of 8.5 million kilometers (5.3 million miles) from Saturn and is but a taste of what the spacecraft's powerful cameras will show when Cassini draws nearer to the planet. The limb of the planet is visible at lower right. <br />The image was taken with the Cassini spacecraft narrow angle camera on Sept. 15, 2004, through a filter sensitive to wavelengths of infrared light. The image scale is 101 kilometers (63 miles) per pixel. The image was magnified by a factor of two and slightly contrast enhanced to improve visibility of features in the atmosphere. </i><br /><br />(edit) Or if the above link isn't working (quickly enough), as it wasn't tonight:<br />http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/saturn/images/PIA06491.jpg&type=image<br />

 

[Leovinus]

<i>This close-up view shows lots of atmospheric detail, including a dark storm and wisps of clouds. The dark spot is noticeably lighter around its perimeter than in its interior.<br /><br />The image was taken with the Cassini spacecraft narrow angle camera on Sept. 10, 2004, at a distance of 8.8 million kilometers (5.5 million miles) from Saturn, through a filter sensitive to wavelengths of infrared light centered at 750 nanometers. The image scale is 52 kilometers (32 miles) per pixel. The image has been contrast enhanced to improve visibility of features in the atmosphere. </i> <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

<i>Saturn's southern hemisphere boasts a great deal of fine detail in the turbulent boundaries between the atmospheric bands in this Cassini image. Note the faint bright spot in the band north of the dark polar region.<br /><br />The image was taken with the Cassini spacecraft narrow angle camera on Sept. 3, 2004, at a distance of 9 million kilometers (5.6 million miles) from Saturn, through a filter sensitive to wavelengths of infrared light. The image scale is 53 kilometers (33 miles) per pixel. </i> <br /><br />http://saturn.jpl.nasa.gov/cgi-bin/gs2.cgi?path=../multimedia/images/saturn/images/PIA06494.jpg&type=image <div class="Discussion_UserSignature"> </div>

 

[anoolios]

There is going to be a free public Cassini event at the University of Arizona in Tucson on October 16.<br /><br />http://uanews.org/cgi-bin/WebObjects/UANews.woa/5/wa/SRStoryDetails?ArticleID=9775

 

[Leovinus]

<i>The southern edge of Saturn's equatorial band displays a scalloped appearance in this Cassini image, as clouds of bright material are stretched and pulled like taffy.<br /><br />The shadow of Saturn's rings is visible through the thin C ring at upper right.<br /><br />The image was taken with the Cassini spacecraft narrow angle camera on Sept. 13, 2004, at a distance of 8.6 million kilometers (5.3 million miles) from Saturn, through a filter sensitive to wavelengths of infrared light. The image scale is 103 kilometers (32 miles) per pixel. Contrast was enhanced to improve visibility of features in the atmosphere. </i><br /><br />13 days, 20 hours until Titan Encounter <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

<i>Cassini spied two members of Saturn's family rounding the rings in this image from Aug. 20, 2004.<br /><br />The moons visible in this image are Mimas (398 kilometers, or 247 miles across) near upper right, and Epimetheus (116 kilometers, or 72 miles across) near the center, outside the faint F ring.<br /><br />Three major gaps in Saturn's rings can be seen here as well. The Cassini division (4,800 kilometer or 2,980 miles wide) is the dark swath at lower right. The Encke Gap (325 kilometers or 202 miles wide) and narrow Keeler Gap (35 kilometers or 22 miles wide) are visible as dark arcs near the edge of the A ring. Small clumps of material are visible in the narrow F ring, beyond the edge of the main rings.<br /><br />The image was taken in visible light with the Cassini spacecraft narrow angle camera at a distance of 9 million kilometers (5.6 million miles) from Saturn. The image scale is 54 kilometers (34 miles) per pixel. Atlas has been brightened to improve visibility. </i> <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

<i>Cassini caught this intriguing view of a dark storm near the limb of Saturn on Sept. 9, 2004. The image shows a great deal of detail in the gas giant's turbulent atmosphere.<br /><br />The bright triangle at right is an overexposed part of Saturn's A ring, with the F ring faintly visible beneath.<br /><br />The image was taken with the Cassini spacecraft narrow angle camera at a distance of 8.8 million kilometers (5.5 million miles) from Saturn, through a filter sensitive to wavelengths of infrared light. The image scale is 104 kilometers (65 miles) per pixel. The image was magnified by a factor of two and slightly contrast-enhanced to improve visibility of features in the atmosphere. </i> <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

<i>In this image, Dione, a moon of Saturn, exhibits some of the interesting bright and dark markings for which it is renowned. From Voyager images, Dione is known to have bright wispy markings, some of which may be visible here. Dione is 1,118 kilometers (695 miles) wide.<br /><br />The image was taken in visible light with the Cassini spacecraft narrow angle camera on Sept. 15, 2004, at a distance of 8.8 million kilometers (5.4 million miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 83 degrees. The image scale is 53 kilometers (33 miles) per pixel. The image has been magnified by a factor of four and contrast-enhanced to aid visibility. </i> <div class="Discussion_UserSignature"> </div>

 

[peteb]

No one has commented so far on the Iapetus raw image sequences from the last few days. Cassini has just passed about 1.1 million km from the satellite (~2.4 million was the previous closest flyby), but there is evidently a pointing error for many of the raw narrow angle images released so far. Only a few actually have Iapetus in the frame, e.g.<br />http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=23503<br />http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=23928<br />http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feiImageID=23597

 

[Leovinus]

Those images are really cool, but I'm concerned about the pointing error. Was that a human error in building the commands for uplink or was it a hardware failure on Cassini? <div class="Discussion_UserSignature"> </div>

 

[peteb]

It was addressed in yesterday's Significant Event Report<br /><br />"The Spacecraft Operations Office ran a successful test of the Iapetus Live Inertial Vector Propagator (IVP) Update in the Integrated Test Laboratory (ITL) this week. The Flight Software Development System (FSDS) run also completed successfully. The ACS data from the test was reviewed and the files were verified for uplink. The pointing difference, during the Iapetus observation, between the FSDS C-Kernel and the Preliminary Sequence Integration and Validation (PSIV) 2 C-Kernel is 4.1 mrads. This is consistent with known ephemeris differences. "<br /><br />Hopefully they were able to upload new values for the closest approach shots, which I now think is either today or tomorrow. If actually in the frame those should be a little higher resolution than the best ones from Voyager. And it's only 2 1/2 months untill much better ones.

 

[Leovinus]

Can anybody translate that into English? <div class="Discussion_UserSignature"> </div>

 

[alokmohan]

From greek to enlish?Good one.

 

[Swampcat]

I was playing around with some of the Cassini raw images and came up with this interesting false color composite.<br /><br />The raw images were taken from a distance of about 4.6 million kilometers from Saturn on Oct. 15. <div class="Discussion_UserSignature"> <font size="3" color="#ff9900"><p><font size="1" color="#993300"><strong><em>------------------------------------------------------------------- </em></strong></font></p><p><font size="1" color="#993300"><strong><em>"I hold it that a little rebellion now and then is a good thing, and as necessary in the political world as storms in the physical. Unsuccessful rebellions, indeed, generally establish the encroachments on the rights of the people which have produced them. An observation of this truth should render honest republican governors so mild in their punishment of rebellions as not to discourage them too much. It is a medicine necessary for the sound health of government."</em></strong></font></p><p><font size="1" color="#993300"><strong>Thomas Jefferson</strong></font></p></font> </div>

 

[decepticon]

Some pics here from the 15th.<br />http://saturn1.jpl.nasa.gov/multimedia/images/raw/raw-images-list.cfm?StartRow=49&cacheQ=1&browseLatest=0&storedQ=586614<br /><br />http://saturn1.jpl.nasa.gov/multimedia/images/raw/raw-images-list.cfm?StartRow=65&cacheQ=1&browseLatest=0&storedQ=586614<br /><br /><br />We should get some better than this soon.<br /><br />

 

[Leovinus]

<i>This turbulent boundary between two latitudinal bands in Saturn's atmosphere curls repeatedly along its edge in this Cassini image. This pattern is an example of a Kelvin-Helmholtz instability, which occurs when two fluids of different density flow past each other at different speeds. This type of phenomenon should be fairly common on the gas-giant planets given their alternating jets and the different temperatures in their belts and zones.<br /><br />The image was taken with the Cassini spacecraft narrow angle camera on Oct. 9, 2004, at a distance of 5.9 million kilometers (3.7 million miles) from Saturn through a filter sensitive to wavelengths of infrared light centered at 889 nanometers. The image scale is 69 kilometers (43 miles) per pixel. </i> <div class="Discussion_UserSignature"> </div>

 

[odysseus145]

I was looking at Cassini's current position and I was wondering why there aren't any press releases of Iapetus. There seem to be plenty of raw images. How long does it take to turn a raw image into a press release image? <div class="Discussion_UserSignature"> </div>

 

[decepticon]

I've been wondering the same thing.<br /><br />It also bugs me as to why these distant views are not shown on encounter charts to let the public know when Intresting targets will be seen.

 

[gregoire]

Appears that there was only one raw image today.......any ideas why?

 

[Leovinus]

<i>Wavy bands in Saturn's high atmosphere lazily circle the south polar region in this Cassini image, taken through a filter sensitive to ultraviolet light.<br /><br />At these wavelengths, gas in the atmosphere scatters sunlight more than the particles that make up the clouds, so the clouds look dark. This scattering of short-wavelength light by gas molecules is called Rayleigh scattering, and is the phenomenon that makes Earth's sky look blue.<br /><br />The bright wedge near the lower-left limb of the planet falls in a latitude band just south of the dark `polar collar'. Imaging scientists can discern from this image that the stratosphere in this more southerly latitude band is relatively pure hydrogen and helium and contains very little of the stratospheric haze that causes darkening closer to the pole.<br /><br />This image was taken with the Cassini spacecraft narrow angle camera on Aug. 27, 2004, at a distance of 9 million kilometers (5.6 million miles) from Saturn. The image scale is 108 kilometers (67 miles) per pixel. </i> <div class="Discussion_UserSignature"> </div>

 

[volcanopele2]

Decepticon,<br /><br />The period from image capture to public release (not talking about the raw images) can vary by the scientific importance of the image's results and who "owns" the image, i.e. who on the imaging team requested the image to be taken. Not sure about the new Iapetus observations though.

 

[Leovinus]

<i>As it approached Saturn near the end of its second orbit, Cassini caught this view of the small, irregularly shaped moon Hyperion (266 kilometers, or 165 miles, across). The moon's long axis is nearly horizontal in this view. The image shows parts of Hyperion's day and night sides.<br /><br />Hyperion is a heavily cratered body, though Cassini's cameras were not able to discern much detail from the distance at which the image was taken. The spacecraft is slated to fly past the little moon at an altitude of less than 1,000 kilometers (620 miles) in late 2005, compared with a distance of 5.9 million kilometers (3.7 million miles) between Hyperion and Cassini when this image was taken.<br /><br />The image was taken in visible light with the Cassini spacecraft narrow angle camera on Sep. 29, 2004, at a Sun-Hyperion-spacecraft, or phase, angle of 75 degrees. The image scale is 35 kilometers (22 miles) per pixel. The image has been magnified by a factor of four to aid visibility. </i> <div class="Discussion_UserSignature"> </div>

 

[peteb]

I see that there is now a Titan flyby description PDF (6MB) on the Cassini page. There's a more detailed timeline and snapshots of some of the instrument pointing views. If volcanopele isn't too busy right now and sees this maybe he can explain the different views. I think that in the first panel the outer white box is for the wide angle ISS, the orange box is for VIMS (Visual and IR Mapping Spectrometer), the small white box is the narrow angle ISS and the circle may be for CIRS ( Composite IR Spectrometer). I'm not sure about the elongated purple boxes or some of the different sized circles in later panels (radar?)http://saturn.jpl.nasa.gov/home/index.cfm