Cassini/Huygens Mission Update Thread

[crowing]

Great pictures leo

 

[Leovinus]

<i>This view of Saturn's south pole shows a prominent dark spot, along with flowing, wave-like patterns to the north and toward the right.<br /><br />This image was taken with the Cassini spacecraft narrow angle camera on July 13, 2004, from a distance of 5 million kilometers (3.1 million miles) from Saturn, through a filter sensitive to wavelengths of infrared light centered at 889 nanometers. The image scale is 29 kilometers (18 miles) per pixel. Contrast has been enhanced slightly to aid visibility. </i> <div class="Discussion_UserSignature"> </div>

 

[jcdenton]

Keep those pics coming Leo... <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

<i>This image represents Cassini's best view yet of Saturn's battered and chaotically rotating little moon Hyperion. Hyperion, pronounced "high-PEER-ee-on," is 266 kilometers (165 miles) across. Cassini was, at the time, speeding away from the Saturn system on its initial long, looping orbit. Hyperion has an irregular shape and is known to tumble erratically in its orbit. Cassini is scheduled to fly past this moon on September 26, 2005.<br /><br />This image was taken in visible light with the Cassini spacecraft narrow angle camera on July 15, 2004, from a distance of about 6.7 million kilometers (4.1 million miles) from Hyperion. The Sun- Hyperion-spacecraft, or phase angle of this image is 95 degrees. The image scale is 40 kilometers (25 miles) per pixel. The image has been magnified by a factor of four to aid visibility. </i> <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

<i>The image on the left was taken on Nov. 1, 1980, by NASA's Voyager spacecraft from a distance of 5.3 million kilometers (3.3 million miles). It shows a very strong narrow shadow cast on the equatorial region of Saturn's atmosphere by the rings. During the Voyager encounters, the Sun was close to the plane of the rings so that the ring shadow was very deep and localized to low latitudes.<br /><br />Radio signals detected by Voyager were interpreted as lightning coming from a persistent, extended storm system at low latitudes. It is possible that the ring shadow was partly responsible for generating this storm by promoting strong convection at the boundary of the colder shadowed atmosphere and the adjoining sunlit atmosphere. This image was previously released on June 19, 1999. For original caption see PIA00335.<br /><br />The image on the right was acquired by the Cassini spacecraft on May 10, 2004, from a distance of 27.2 million kilometers (16.9 million miles) and shows the complex set of ring shadows cast over a large region of Saturn's northern hemisphere. This shadow pattern is due to the Sun being well below the ring plane during Cassini's approach to Saturn. This image was previously release on May 25, 2004. For original caption see PIA05394.<br /><br />Unlike the situation when NASA's Voyager spacecraft flew by Saturn, these ring shadows are not as deep and are not localized at a very narrow range of latitudes. Should these shadows drive convection in Saturn's atmosphere, the location would likely be very much different than the near-equatorial shadow observed by the Voyagers in the early 1980s. It is possible that this very different ring shadow geometry is one reason for different morphologies of thunderstorms observed by Cassini and Voyager. Voyager observed lightning apparently from one persistent, low-latitude storm system, whereas Cassini observes lightning from storms which seem to come and go on time scales of a day or so, and perhaps from more than one</i> <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

Just my opinion: I think that picture on the left is one of the coolest pictures taken during the Voyager program. <div class="Discussion_UserSignature"> </div>

 

[commander_keen]

As cool as the pictures are, they dont give us any impression of the immensity of these planets. If we were their right now, we would probably be looking at the largest object that we've ever witnessed close up. The size of these planets are just astounding.

 

[aaron38]

Why do background stars apear in the lefthand Voyager image? They aren't visable in any of the Cassini shots. Or at least not like that.

 

[Leovinus]

I don't see any stars in that image. One of us needs eyes checked. But if there are pinpoints of light, they could be satellites. I think there are 20 or 30 of them floating around there somewhere. <div class="Discussion_UserSignature"> </div>

 

[Leovinus]

<i>Saturn's atmosphere displays elegant structural detail in this image of the southern polar region. Swirls, fingers of clouds and three subtle brighter spots are visible here as they race around the planet. A dark spot surrounded by concentric rings marks the south pole.<br /><br />The image was taken with the Cassini spacecraft narrow angle camera on July 13, 2004, from a distance of 5.1 million kilometers (3.2 million miles) from Saturn, through a filter sensitive to wavelengths of infrared light centered at 889 nanometers. The image scale is 30 kilometers (19 miles) per pixel. Contrast has been enhanced slightly to aid visibility. </i> <div class="Discussion_UserSignature"> </div>

 

[najab]

There are pinpoints of light and they ain't satellites. Them be stars! The reason you can see stars in the Voyager image is that it is over-exposed. Note the lack of detail in Saturn itself - the Cassini images are better exposed to bring out the detail in Saturn, so the stars don't register. I'm willing to bet that if you took the Cassini raw file of that image and upped the brightness you would see stars.

 

[thalion]

I'm not so sure that those are stars; I've seen that image many times before, and have never seen any stars. My op is that it's image noise--though why it would be in that image and not in the ones published elsewhere, I have no idea, unless it's a raw image.

 

[spacechump]

Maybe Saturn is just superimposed over a created starry background for effect.

 

[najab]

You know, looking at the image again, you're right. The pattern of dots is too regular. Perhaps a scanning artifact.

 

[jcdenton]

<font color="yellow">The pattern of dots is too regular.</font><br /><br />That was my thought as well. <div class="Discussion_UserSignature"> </div>

 

[pr0ject0rion]

Just think. If those anti-nuclear nuts who protested the Cassini launch had successfully cowed the government into folding on this great mission, then none of these images would be possible. It wouldn't have been the first time a nuclear powered mission was cancelled because of such fearmongering. Kind of frightening really. Now the same bunch of wackos want to kill off Prometheus. That project faces enough challenges without the mindless interference from these straw men and bored housewives. We've probably learned more about saturn in the last few months than we did in the previous 20 years. Anti-technologists sicken me.

 

[alokmohan]

Can one tell salient points of cassini mission?In 500 word say?

 

[pr0ject0rion]

Launched from Kennedy Space Center on October 15, 1997, the Cassini-Huygens spacecraft is composed of two elements. The Cassini orbiter that will orbit Saturn and its moons for four years and the Huygens probe that will dive into the murky atmosphere of Titan and land on its surface. <br /><br />Cassini-Huygens is an international collaboration between three space agencies. Seventeen nations contributed to building the spacecraft. The Cassini orbiter was built and managed by NASA's Jet Propulsion Laboratory. The Huygens probe was built by the European Space Agency. The Italian Space agency provided Cassini's high-gain communication antenna. More than 250 scientists worldwide are studying the data collected. <br /><br />On July 1, 2004 the Cassini-Huygens spacecraft fired its main engine to reduce its speed, allowing the spacecraft to be captured by Saturn's gravity and enter orbit. The spacecraft then began a four-year tour of the ringed planet, its mysterious moons, the stunning rings, and its complex magnetic environment. <br /><br />During the Saturn Tour, Cassini will complete 74 orbits of the ringed planet, 44 close flybys of the mysterious moon Titan, and numerous flybys of Saturn's other icy moons. <br /><br />Key dates of the Saturn Tour are: <br /><br />June 11, 2004 (19:32 UTC): Flyby of the furthest moon orbiting Saturn, Phoebe, at an altitude of 2,000 km (1,243 miles). <br /><br />July 1, 2004: Crossing of Saturn's Ring Plane during the spacecraft's critical Saturn Orbit Insertion sequence. <br /><br />Dec. 25, 2004: 02:00 UTC Huygens probe separates from the Cassini orbiter and begins its 21 day journey to Titan. Dec. 25 counts as day one and Jan. 14 is day 21. <br /><br />Jan. 14, 2005: Huygens begins its descent through Titan's cloudy atmosphere, where it lands on the surface about two and half hours later. The probe is scheduled to encounter the upper fringes of Titan's atmosphere at 09:00 UTC. <br /><br />Other highlights of the Saturn Tour include close encounters w

 

[alokmohan]

Full marks.Can we get life in titan?

 

[toymaker]

"Full marks.Can we get life in titan?"<br />I would like to add the following question.<br />Is there any known lifeform that would be able to exist or even thrive in Titan ?

 

[the_ten]

No camera's on the Huygen probe?

 

[remcook]

yes, there will be cameras on the Huygens probe<br /><br />http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=31193

 

[pr0ject0rion]

<blockquote><font class="small">In reply to:</font><hr /><p>Can we get life in Titan? ........ Is there any known lifeform that would be able to exist or even thrive in Titan ?<p><hr /></p></p></blockquote><br /><br />Titan is Saturn's largest satellite. With a diameter of 5150 km (3,218 miles), half our planet's size, Titan is second only to Jupiter's Ganymede (5260 km or 3,288 miles across) and bigger than Mercury, Pluto or the Moon. <br /><br />It is located nine times farther away from the Sun than the Earth and was discovered on March 25, 1655, by a Dutch amateur astronomer and optician, Christiaan <b>Huygens</b> (ring a bell?). It took more than 250 years to discover that Titan had an atmosphere and another 50 years to find out that this atmosphere contained organic material. Titan was, however, mainly revealed to us by the Voyager missions in 1981.<br /><br />Despite its somewhat disappointing appearance on the Voyager images, Titan happens to be the only satellite in our Solar system that has a thick and extended atmosphere, with nitrogen as its main gaseous constituent. The atmosphere of Titan is foggy, and besides nitrogen, it consists of small amounts of methane, and a little molecular hydrogen. In this fascinating environment, methane and nitrogen combine and photodissociate to produce saturated and unsaturated hydrocarbons, nitriles and other organics that eventually fall through the atmosphere and are deposited on the surface.<br /><br />Carl Sagan and others tried to reproduce these organics in the laboratory. What they recovered was a sort of brownish sludge they called "tholin", from the Greek word "Tholos", meaning mud. Biologists believe that when our planet was formed, these molecules, some of which, like hydrogen cyanide or cyanoacetylene, are called prebiotic, contributed to the development of life. The laboratory simulations show that molecules of even higher complexity could be expected on Titan.<br /><br />A day in Titan lasts 16 Earth days while the year lasts a

 

[aaron38]

<i>the light at noontime never gets brighter than twilight on Earth.</i><br /><br />Is this accurate? I guess I never questioned it, (the artists impressions always show it brightly lit right?).<br /><br />Do we need to revise down our expectations for the Huygens probe surface pictures? How much detail are we going to be able to see at that light level?<br /><br />Will the images be primarily in infared then? I imagine the UV wouldn't make it through at all if the visable light doesn't.

 

[Leovinus]

<i>This narrow angle ultraviolet image probes the high atmosphere above Saturn's south pole. A bright wedge near the lower-left limb falls in a latitude band which borders a darker latitude band a little closer to the pole. Viewing the limb of the planet in ultraviolet light allows researchers to sample the high part of the atmosphere (the stratosphere).<br /><br />Scientists can discern from this image that the stratosphere in this latitude band is relatively pure hydrogen and helium and contains very little of the stratospheric haze which causes darkening closer to the pole. The image was taken by the Cassini spacecraft on July 26, 2004, at a distance of 7.1 million kilometers (4.4 million miles) from Saturn. The image scale is 42 kilometers (26 miles) per pixel. Contrast was slightly enhanced to bring out features in the atmosphere. </i> <div class="Discussion_UserSignature"> </div>