Category: Saturn

This view of Saturn’s outer C ring shows the extreme variations in brightness, along with the subtle, large-scale wavy variations discovered 24 years ago by NASA’s Voyager spacecraft. The notably dark Maxwell gap (near upper right) contains the bright, narrow and eccentric Maxwell ringlet, a Saturnian analog of the narrow Uranian epsilon ring. The gap also contains another very faint ringlet newly discovered by Cassini.

The image was taken with the Cassini spacecraft narrow angle camera on Oct. 29, 2004, at a distance of 838,000 (521,000 miles) from Saturn. The center of this view shows an area located approximately 81,300 kilometers (50,500 miles) from the planet. The image scale is 4.6 kilometers (2.9 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

These spectacular Cassini images of Saturn?s moon Iapetus show an enticing world of contrasts.

These are the sharpest views of Iapetus from Cassini so far, and they represent better resolution than the best images of this moon achieved by NASA’s Voyager spacecraft. Images obtained using ultraviolet (centered at 338 nanometers), green (568 nanometers) and infrared (930 nanometers) filters were combined to produce the enhanced color views at left and center; the image at the right was obtained in visible white light. The images on the bottom row are identical to those on top, with the addition of an overlying coordinate grid.

These views show parts of the moon?s anti-Saturn side ? the side that faces away from the ringed planet–which will not be imaged again by Cassini until Sept., 2007. In the central view, part of the moon?s eastern edge was not imaged and appears to be cut off.

With a diameter of 1,436 kilometers (892 miles), Iapetus is Saturn’s third largest moon. It is famous for the dramatic contrasts in brightness on its surface ? the leading hemisphere is as dark as a freshly-tarred street, and the trailing hemisphere and poles almost as bright as snow.

Many impact craters can be seen in the bright terrain and in the transition zone between bright and dark, and for the first time in parts of the dark terrain. Also visible is a line of mountains that appear as a string of bright dots in the two color images at left, and on the eastern limb in the image at right. These mountains were originally detected in Voyager images, and might compete in height with the tallest mountains on Earth, Jupiter’s moon Io and possibly even Mars. Further observations will be required to precisely determine their heights. Interestingly, the line of peaks is aligned remarkably close to the equator of Iapetus.

The large circular feature rotating into view in the southern hemisphere is probably an impact structure with a diameter of more than 400 kilometers (250 miles), and was first seen in low-resolution Cassini images just two months earlier.

These images were taken with the Cassini spacecraft narrow angle camera between Oct, 15 and 20, 2004, at distances of 1.2, 1.1 and 1.3 million kilometers (746,000, 684,000 and 808,000 miles) from Iapetus, respectively. The Sun-Iapetus-spacecraft, or phase, angle changes from 88 to 144 degrees across the three images. The image scale is approximately 7 kilometers (4.5 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

One year after Mars Express? arrival at Mars, the mighty rules of celestial mechanics have again set Christmas as the date for a major ESA event in deep space.

At 1.25 billion km from Earth, after a 7-year journey through the Solar system, ESA?s Huygens probe is about to separate from the Cassini orbiter to enter a ballistic trajectory toward Titan, the largest and most mysterious moon of Saturn, in order to dive into its atmosphere on 14 January. This will be the first man-made object to explore in-situ this unique environment, whose chemistry is assumed to be very similar to that of the early Earth just before life began, 3.8 billion years ago.

The Cassini-Huygens pair, a joint mission conducted by NASA, ESA and the Italian space agency (ASI), was launched into space on 15 October 1997. With the help of several gravity assist manoeuvres during flybys of Venus, Earth and Jupiter, it took almost 7 years for the spacecraft to reach Saturn.

The Cassini orbiter, carrying Huygens on its flank, entered an orbit around Saturn on 1 July 2004, and began to investigate the ringed planet and its moons for a mission that will last at least four years.

The first distant flyby of Titan took place on 2-3 July 2004. It provided data on Titan’s atmosphere which were confirmed by the data obtained during the first close flyby on 26 October 2004 at an altitude of 1174 km. These data were used to validate the entry conditions of the Huygens probe. A second close flyby of Titan by Cassini-Huygens at an altitude of 1200 km is scheduled on 13 December and will provide additional data to further validate the entry conditions of the Huygens probe.

On 17 December the orbiter will be placed on a controlled collision course with Titan in order to release Huygens on the proper trajectory, and on 21 December (some dates and times are subject to minor adjustment for operational reasons, except the entry time on 14 January which is know to within an accuracy of under 2 minutes) all systems will be set up for separation and the Huygens timers will be set to wake the probe a few hours before its arrival at Titan.

The Huygens probe is due to separate on the morning of 25 December at about 05:08 CET. Since the Cassini orbiter will have to achieve precise pointing for the release, there will be no real-time telemetry available until it turns back its main antenna toward Earth and beams the recorded data of the release. It will take over an hour (67 min) for the signals to reach us on Earth. The final data confirming the separation will be available later on Christmas Day.

After release, Huygens will move away from Cassini at a speed of about 35 cm per second and, to keep on track, will spin on its axis, making about 7 revolutions a minute. Huygens will not communicate with Cassini for the whole period until after deployment of the main parachute following entry into Titan?s atmosphere. On 28 December Cassini will then manoeuvre off collision course to resume its mission and prepare itself to receive Huygens data, which it will record for later playback to Earth.

Huygens will remain dormant until a few hours before its arrival at Titan on 14 January. The entry into the atmosphere is set for 11:15 CET. Huygens is planned to complete its descent in about two hours and 15 minutes, beaming back its science data to the Cassini orbiter for replay to Earth later in the afternoon. If Huygens, which is designed as an atmospheric probe rather than a lander, survives touchdown on the surface, it could deliver up to 2 hours of bonus data before the link with Cassini is lost.

Direct radio signals from Huygens will reach Earth after 67 minutes of interplanetary travel at the speed of light. An experiment has been set up by radio scientists that will use an array of radio telescopes around the Pacific to attempt to detect a faint tone from Huygens. If successful, early detection is not expected before around 11:30 CET.

The European Space Agency owns and manages the Huygens probe and is in charge of operations of the probe from its control centre in Darmstadt, Germany. NASA’s Jet Propulsion Laboratory in Pasadena, California, designed, developed and assembled the Cassini orbiter. NASA’s Deep Space Network, also managed by JPL, will be providing communications support via the Cassini orbiter and relaying it to ESA?s control centre in Darmstadt for processing. The Italian Space Agency provided the high-gain antenna on the Cassini orbiter, much of the radio system and elements of several of Cassini’s science instruments. The Huygens payload has been provided by teams including from CNES, DLR, ASI and PPARC, and outside Europe, from NASA.

Original Source: ESA News Release

Any doubts about the grandeur of Saturn’s rings will be dissolved by sweeping portraits like this one from Cassini. There is a magnificent level of detail visible in this view, which captures almost the entire ring system — from the thin, outer F ring to faint narrow features in the D ring, interior to the C ring. Along the ringplane, differences in brightness reveal the varying concentrations of the particles that comprise the rings.

Cassini is viewing the rings from below. The portion of the rings near the top of the image is closer to the spacecraft, and the portion near the bottom is farther away.

The image was taken with the Cassini spacecraft wide angle camera on Oct. 29, 2004, at a distance of about 836,000 (519,000 miles) from Saturn through a filter sensitive to wavelengths of infrared light centered at 742 nanometers. The image scale is 46 kilometers (29 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

As it completed its first orbit of Saturn, Cassini zoomed in on the rings to catch this wondrous view of the shepherd moon Prometheus (102 kilometers, or 63 miles across) working its influence on the multi-stranded and kinked F ring.

The F ring resolves into five separate strands in this closeup view. Potato-shaped Prometheus is seen here, connected to the ringlets by a faint strand of material. Imaging scientists are not sure exactly how Prometheus is interacting with the F ring here, but they have speculated that the moon might be gravitationally pulling material away from the ring. The ringlets are disturbed in several other places. In some, discontinuities or “kinks” in the ringlets are seen; in others, gaps in the diffuse inner strands are seen. All these features appear to be due to the influence of Prometheus.

The image was taken in visible light with the narrow angle camera on Oct. 29, 2004, at a distance of about 782,000 kilometers (486,000 miles) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 147 degrees. The image scale is 4.7 kilometers (2.9 miles) per pixel. The image has been magnified by a factor of two, and contrast was enhanced, to aid visibility.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

An intriguing knotted ringlet within the Encke Gap is the main attraction in this Cassini image. The Encke Gap is a small division near the outer edge of Saturn’s rings that is about 300 kilometers (190 miles) wide. The tiny moon Pan (20 kilometers, or 12 miles across) orbits within the gap and maintains it. Many waves produced by orbiting moons are visible.

The image was taken in visible light with the Cassini spacecraft narrow angle camera on Oct. 29, 2004, at a distance of about 807,000 kilometers (501,000 miles) from Saturn. The image scale is 4.5 kilometers (2.8 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Original Source: NASA/JPL News Release

In a splendid portrait created by light and gravity, Saturn’s lonely moon Mimas is seen against the cool, blue-streaked backdrop of Saturn’s northern hemisphere. Delicate shadows cast by the rings arc gracefully across the planet, fading into darkness on Saturn’s night side.

The part of the atmosphere seen here appears darker and more bluish than the warm brown and gold hues seen in Cassini images of the southern hemisphere, due to preferential scattering of blue wavelengths by the cloud-free upper atmosphere.

The bright blue swath near Mimas (398 kilometers, or 247 miles across) is created by sunlight passing through the Cassini division (4,800 kilometers, or 2,980 miles wide). The rightmost part of this distinctive feature is slightly overexposed and therefore bright white in this image. Shadows of several thin ringlets within the division can be seen here as well. The dark band that stretches across the center of the image is the shadow of Saturn’s B ring, the densest of the main rings. Part of the actual Cassini division appears at the bottom, along with the A ring and the narrow, outer F ring. The A ring is transparent enough that, from this viewing angle, the atmosphere and threadlike shadows cast by the inner C ring are visible through it.

Images taken with red, green and blue filters were combined to create this color view. The images were obtained with the Cassini spacecraft narrow angle camera on Nov. 7, 2004, at a distance of 3.7 million kilometers (2.3 million miles) from Saturn. The image scale is 22 kilometers (14 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Original Source: NASA/JPL News Release

A gorgeous Dione poses for Cassini, with shadowed craters and bright, wispy streaks first observed by the Voyager spacecraft 24 years ago. The wispy areas will be imaged at higher resolution in mid-December 2004. Subtle variations in brightness across the surface of this moon are visible here as well. Dione’s diameter is 1,118 kilometers, (695 miles).

The image shows primarily the trailing hemisphere of Dione, which is the side opposite the moon’s direction of motion in its orbit. The image has been rotated so that north is up.

The image was taken in visible light with the Cassini spacecraft narrow angle camera on Oct. 27, 2004, at a distance of about 1.2 million kilometers (746,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 28 degrees. The image scale is 3.5 kilometers (2.2 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Original Source: NASA/JPL News Release

Image credit: NASA/JPL/SSI
New views of two of Saturn’s moons, Titan and Tethys, represent the most detailed look at these moons to date and show a sharp contrast between them — one is foggy and one is cratered.

The Cassini spacecraft captured the puzzle pieces for the full-disc view of the mysterious Titan during its first close encounter on Oct. 26, 2004. The mosaic comprises nine images taken at distances ranging from 650,000 kilometers (400,000 miles) to 300,000 kilometers (200,000 miles).

The pictures are available at http://saturn.jpl.nasa.gov, http://www.nasa.gov/cassini and http://ciclops.org.

The images that make up the mosaic were processed to reduce effects of the atmosphere and to sharpen surface features. The mosaic of images has been trimmed to show only the illuminated surface and not the atmosphere around the edge of the moon. The Sun was behind Cassini, so nearly the full disc was illuminated. South polar clouds are seen at the bottom.

Surface features are best seen near the center of the moon. The surface features become fuzzier toward the outside of the image, where the spacecraft is peering through more haze. The brighter region on the right side near the equator is named Xanadu Regio. Scientists are debating what processes may have created the bizarre surface brightness patterns seen there. Titan’s lack of obvious craters is a hint of a young surface. However, the exact nature of that activity, whether tectonic, wind-blown, river-related, marine or volcanic, is still unknown.

Two days after the close encounter with icy Titan, Cassini captured the images used in the mosaic of the battered and cratered moon Tethys. The result is the best-ever natural color view of Titan.

As seen here, the surface of Tethys has a neutral hue. Three images form this natural color composite. The mosaic reveals a world nearly saturated with craters — many small craters lie on top of older, larger ones, suggesting an ancient surface. Grooves can be seen at the top and along the boundary between day and night.

Tethys is known to have a density very close to that of water, indicating that it is likely composed mainly of water ice. Its frozen mysteries await Cassini’s planned close flyby in September 2005.

The images to create this mosaic were taken on Oct. 28, 2004, at a distance of about 256,000 kilometers (159,000 miles) from Tethys. This view shows the trailing hemisphere of Tethys, which is the side opposite the moon’s direction of motion in its orbit.

Both images were taken with the narrow angle camera onboard the Cassini spacecraft. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

Original Source: NASA/JPL News Release

This dazzling view looks beyond gigantic storms near Saturn’s south pole to the small but clear disc of Tethys (1,060 kilometers, or 659 miles, across). Clouds and ribbons of gas swirl about in the planet’s atmosphere in the foreground, while a tremendous chasm is visible on the icy moon.

The image was taken with the Cassini spacecraft narrow angle camera on Oct. 18, 2004, at a distance of 3.9 million kilometers (2.4 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 61 degrees. The view is in wavelengths of visible red light centered at 619 nanometers. The image scale is 23 kilometers (14 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org .

Original Source: NASA/JPL News Release