Cassini/Huygens Mission Update Thread

[volcanopele2]

"This color image of Iapetus was put together using the IR1, GRN & UV3 filters of Cassini's narrow angle camera. The raw images were taken 07/13/2004 from a distance of approx. 2.5 million kilometers. Some processing was done."<br /><br />I would be very careful in interpreting any color products produced from the raw images posted on the Cassini website. The stretch preformed on them before posting makes them very poor for color products.<br /><br />However the straight grayscale images are interesting. From this set and another taken on July 2 (or 3) we can tell that there are at least 2 large impact basins in Cassini Regio with perhaps another to the south of the one shown in your post. The one in the July 2nd set is nearly 500 km (~5/7 of Iapetus' radius) while the one seen in your post is around 325 km across (a bit less than half Iapetus' radius).

 

[centsworth_II]

<i>"Yep, the RADAR instrument will be used on an area north of the "H".</i> -- volcanopele2<br /><br />Which unfortunately is away from the Huygens landing area. But I'll be interested in seeing more detail on that mysterious H. I hope we will get a much better look at the Huygens landing area as well during the flyby. <div class="Discussion_UserSignature"> </div>

 

[alexblackwell]

<i>The initial orbital period about Saturn post SOI was 112 days so it is about 97 days from now, however a major burn will raise the orbits low point to above the rings and thus change the orbital period.</i><br /><br />Yes, the Periapsis Raise Maneuver (PRM) is currently scheduled for August 23, 2004.<br /><br />From a science standpoint, there are plenty of observations scheduled for the interval between the first non-targeted Titan flyby (T0 on July 2, 2004) and the first targeted Titan flyby (Ta on October 26, 2004). The two sequences that will be operational onboard during this time, S03 and S04, are already built and, I believe, have been uploaded. In fact, during S04, which goes active on September 12, 2004, the Saturn Target Working Team (TWT) plans to conduct the longest continuous near-global Saturn atmospheric campaign of the entire tour. S04 will also include ring observations and observations of 8 major satellites, as well as some low resolution imagery of Phoebe. Fields and particles and waves data will also be collected in near-continuous mode, except when the magnetometer is "muted" during Huygens Probe checkout.<br />

 

[volcanopele2]

ISS will get coverage over the Huygens landing site during Ta and Tb

 

[Swampcat]

<font color="yellow">"I would be very careful in interpreting any color products produced from the raw images posted on the Cassini website. The stretch preformed [sic] on them before posting makes them very poor for color products."</font><br /><br />Thanks for your comments.<br /><br />From my work on MER images I am aware of the problems associated with the normalization that is part of the imaging process. Before posting this particular image, I compared it with color images of Iapetus from other sources and adjusted the contrast and brightness of the color channels accordingly. I certainly am not claiming that this is a "true" color, but I personally find color composites to be more interesting than the greyscale images.<br /><br />Also, I mentioned the filters I used for the composites to make it clear that I was not using the standard RGB filters. A lot of the MER "color" composites that JPL puts out also use the IR for red and UV for blue which obviously is not the best choice, but acceptable for "approximate" true color images, along with some additional processing. At least that has been my experience. <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>

 

[fangsheath]

Thank you. 97 days would put us on 20 Oct, only 6 days from the scheduled Titan flyby. Is the flyby on the third orbit?

 

[alexblackwell]

<i>Thank you. 97 days would put us on 20 Oct, only 6 days from the scheduled Titan flyby. Is the flyby on the third orbit?</i><br /><br />Ta (October 26, 2004) occurs during Rev A, officially the second orbit.<br />

 

[alexblackwell]

Huygens in perfect health<br />July 15, 2004<br />

 

[Leovinus]

<i> The moon with the split personality, Iapetus, presents a puzzling appearance. One hemisphere of the moon is very dark, while the other is very bright. Whether the moon is being coated by foreign material or being resurfaced by material from within is not yet known.</i> <div class="Discussion_UserSignature"> </div>

 

[decepticon]

Is that a voyager pic?<br /><br />It almost hints at more craters in the dark areas.<br />I can't wait to see! So excited!<br />

 

[thinice]

<i>Is that a voyager pic?</i><br /><br />No, JPL has just released it.

 

[Leovinus]

One thing's for sure: If Voyager could take a pic like that from where it is now, that would be one hell of a camera. <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

After the disappointment due to Galileo's stuck antenna, this mission is going to be a feast for the eyes. <div class="Discussion_UserSignature"> </div>

 

[decepticon]

Yes very true. I was looking forward to high detailed maps of europa. Even with all those Europa flybys europa is so poorly mapped.

 

[Leovinus]

<i>This dramatic view of Saturn's rings draped by the shadow of Saturn, shows brightness variations that correspond to differences in the concentration of the ring particles as they orbit the planet.<br /><br />The planet's western limb is visible in the upper right corner. Three of Saturn's moons can be seen here: Bright Enceladus (499 kilometers, or 310 miles across) is visible near lower right; Epimetheus (116 kilometers, or 72 miles across) appears at center left; and interior to the F ring, near the top of the image, is Prometheus (102 kilometers, or 63 miles across). The F ring, the outermost ring shown here, displays several knot-like features near the left side of the image.<br /><br />The image was taken in visible light by the Cassini spacecraft wide angle camera on July 3, 2004, from a distance of 1.5 million kilometers (930,000 miles) from Saturn, at a Sun-Saturn-spacecraft, or phase, angle of about 108 degrees. This is the first processed wide angle camera image to be released since Cassini's encounter with Jupiter in 2000. The image scale is 87 kilometers (54 miles) per pixel. </i> <div class="Discussion_UserSignature"> </div>

 

[decepticon]

Looks like "spokes" are no longer around.

 

[Leovinus]

Seeing as how we're going to be lingering for 4 years or more, I'd say wait a while for the weather to change. <div class="Discussion_UserSignature"> </div>

 

[omegamogo]

That last pic is…mesmerizing

 

[fangsheath]

Valid point, yet I am struck by how singularly devoid the rings seem to be of these "spokes" right now. In general I am surprised at how dynamic they are, given that their basic structure has not changed appreciably for hundreds of years. Does anyone know if there will be shots near the ring plane on the next pass?

 

[Leovinus]

<i>The icy, cratered surface of Saturn's moon Dione shows more than just its sunlit side in these two processed versions of the same image.<br /><br />The view at left, with only mild enhancement, shows a romantic crescent with large craters visible. The contrast in the version at the right has been greatly enhanced to show the side of Dione lit faintly by reflected light from Saturn. A similar phenomenon can be seen from Earth, when the Moon's dark side is visible due to "earthshine." The crater at the top of the image appears to have a sunlit central peak in the enhanced view - a common characteristic of craters on Dione as seen in Voyager images. Slight variations in brightness on the moon's dark side hint at the bright curved linear streaks, seen by Voyager. These streaks are thought to be deposits of water ice.<br /><br />The image was taken with the Cassini spacecraft narrow angle camera on July 2, 2004, from a distance of about 1.4 million kilometers (860,000 thousand miles) from Dione, at a Sun-Dione-spacecraft, or phase angle of about 119 degrees. The image scale is 8 kilometers (5 miles) per pixel. Dione's diameter is 1,118 kilometers (695 miles) across. The images have been magnified by a factor of two to aid visibility. </i> <div class="Discussion_UserSignature"> </div>

 

[mah_fl]

The ESA Cassini-Huygens site shows the orbits nicely, you can also view the whole 4 year tour.<br />http://www.esa.int/export/SPECIALS/Cassini-Huygens/SEMD6E2VQUD_0.html<br />

 

[fangsheath]

But that doesn't tell me if imagery will be taken near the ring plane on the next pass. I realize that is somewhat of an arbitrary criterion.

 

[decepticon]

AT least ESA provides some idea of what incounted during each orbit. I didn't cassinni comes perty close to Iapetus just before the 2nd Titan flyby.<br /><br />This orbit is gonna be a jewel for moon pics.

 

[Leovinus]

<i>The first artificial satellite in the Saturn system, the Cassini spacecraft, returned images of the natural moons following a successful insertion into orbit. This is an unmagnified view of the moon Rhea.<br /><br />With a diameter of 1,528 kilometers (950 miles) across, Rhea is Saturn's second largest moon. The Voyager spacecraft found that like Dione, Rhea has one of its hemispheres covered with bright, wispy streaks which may be water frost.<br /><br />This view shows a heavily cratered surface, and thus it is most likely ancient. Many of the craters visible here have central peaks. Cassini soon will look for clues to help unlock the moon's geologic history. The spacecraft is slated to fly by Rhea at a distance of only 500 kilometers (311 miles) on Nov. 26, 2005.<br /><br />The image was taken in visible light with the Cassini spacecraft narrow angle camera on July 2, 2004, from a distance of about 990,000 kilometers (615,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase angle of about 109 degrees. The image scale is 6 kilometers (4 miles) per pixel. </i> <div class="Discussion_UserSignature"> </div>

 

[peteb]

Decepticon -<br /><br />Since you are interested in the Iapetus flyby at the end of this year, here is a site with an animation, as well as all Iapetus encounters during the 4 year tour and all Cassini orbits around Saturn. You probably need a high speed connection (I don't know how a dial-up connection would do) and the last one is very big (255 MB) - it took about 40 minutes to download on DSL.<br /><br />Btw, the highest ISS resolution during the upcoming flyby will be ~40X better than the recently released images.<br /><br />http://solarsystem.dlr.de/PG/cassini/mission/orbit.shtml