Category: Saturn

Image credit: NASA/JPL/Space Science Institute
Phoebe?s true nature is revealed in startling clarity in this mosaic of two images taken during Cassini?s flyby on June 11, 2004. The image shows evidence for the emerging view that Phoebe may be an ice-rich body coated with a thin layer of dark material. Small bright craters in the image are probably fairly young features. This phenomenon has been observed on other icy satellites, such as Ganymede at Jupiter. When impactors slammed into the surface of Phoebe, the collisions excavated fresh, bright material — probably ice — underlying the surface layer. Further evidence for this can be seen on some crater walls where the darker material appears to have slid downwards, exposing more light-colored material. Some areas of the image that are particularly bright ? especially near lower right ? are over-exposed.

An accurate determination of Phoebe?s density ? a forthcoming result from the flyby ? will help Cassini mission scientists understand how much of the little moon is comprised of ices.

This spectacular view was obtained at a phase, or Sun-Phoebe-spacecraft, angle of 84 degrees, and from a distance of approximately 32,500 kilometers (20,200 miles). The image scale is approximately 190 meters (624 feet) per pixel. No enhancement was performed on this image.

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 Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

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: CICLOPS News Release

Image credit: NASA/JPL/Space Science Institute
As Cassini sails toward its rendezvous with Phoebe, details on the small, dark moon are coming into view at a dizzying pace. The images shown here were taken only 13 hours apart on June 10, 2004, just one day prior to closest approach, and show a dramatic increase in detail between these two views. On Phoebe, the spin axis points up and approximately 13 degrees to the left of the boundary between day and night. Phoebe completes one rotation about its spin axis in 9 hours and 16 minutes. We are looking at opposite hemispheres in these two views.

A large crater, roughly 50 km (31 miles) across, is visible in the image on the left. The image on the right shows a body heavily pitted with craters of varying sizes, including very large ones, and displaying a substantial amount of variation in surface brightness. Features that appear to be cliffs may in fact be the boundaries between large craters. Despite its exaggerated topography, Phoebe is more round than irregular in shape.

Left to right, the two views were obtained at a phase, or Sun-Phoebe-spacecraft, angle of 87 degrees, and from distances ranging from 956,000 kilometers (594,000 miles) to 658,000 kilometers (409,000 miles). The image scale ranges from 5.7 to 3.9 kilometers (3.5 to 2.4 miles) per pixel. To aid visibility, the images were magnified three times via linear interpolation; no contrast enhancement was performed.

Phoebe is approximately 220 kilometers (137 miles) wide. Its many secrets await as Cassini draws close to its only flyby with this mysterious outer moon of Saturn at 1:56 pm PDT on June 11, 2004.

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 Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

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: CICLOPS News Release

Image credit: NASA/JPL/Space Science Institute
The Cassini spacecraft is closing in fast on its first target of observation in the Saturn system: the small, mysterious moon Phoebe, only 220 kilometers (137 miles) across.

The three images shown here, the latest of which is twice as good as any image returned by the Voyager 2 spacecraft in 1981, were captured in the past week on approach to this outer moon of Saturn. Phoebe’s surface is already showing a great deal of contrast, most likely indicative of topography, such as tall sunlit peaks and deep shadowy craters, as well as genuine variation in the reflectivity of its surface materials. Left to right, the three views were captured at a Sun-Saturn-spacecraft, or phase, angle of 87 degrees between June 4 and June 7, from distances ranging from 4.1 million km (2.6 million miles) to 2.5 million km (1.5 million miles). The image scale ranges from 25 to 15 km (16 to 9 miles) per pixel.

The images have been magnified eight times using a linear interpolation scheme; the contrast has been untouched. Phoebe rotates once every 9 hours and 16 minutes; each of these images shows a different region on Phoebe.

Cassini’s powerful cameras will provide the best-ever look at this moon on Friday, June 11, when the spacecraft will streak past Phoebe at a distance of only about 2,000 kilometers (1,240 miles) from the moon’s surface. The current images, and the presence of large craters, promise a heavily cratered surface which will come into sharp view over the next few days when image scales should shrink to a few 10’s of meters…the size of office buildings.

Because of its small size and retrograde orbit – Phoebe orbits Saturn in a direction opposite to that of the larger inner Saturnian moons – and because of the presence of water ice on its surface, Phoebe is believed to be a body from the distant outer solar system, one of the building blocks of the outer planets that was captured into orbit around Saturn. If true, the little moon will provide a windfall of precious information about a primitive piece of the solar system that has never before been explored up close.

Phoebe was the first moon discovered using photography in 1898 and has a very dark surface. It has long been believed that material coming from Phoebe’s surface and impacting the very dark leading hemisphere of Iapetus may play some role in thelatter’s extreme albedo asymmetry, though the precise relationship is unclear. Cassini should help solve this and other mysteries during its exciting encounter with Phoebe.

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 Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

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: CICLOPS News Release

Image credit: NASA/JPL/Space Science Institute
The path that lies ahead for the Cassini -Huygens mission is indicated in this image which illustrates where the spacecraft will be just 27 days from now, when it arrives at Saturn and crosses the ring plane 25 minutes before performing its critical orbital insertion maneuver.

The X indicates the point where Cassini will pierce the ring plane on June 30, 2004, going from south to north of the ring plane, 25 minutes before the main engine fires to begin orbital insertion. The indicated point is between the narrow F-ring on the left and Saturn?s tenuous G-ring which is too faint to be seen in this exposure.

The image was taken on May 11, 2004 when the spacecraft was 26.3 million kilometers (16.3 million miles) from Saturn. Image scale is 158 kilometers (98 miles) per pixel. Moons visible in this image: Janus (181 kilometers, 113 miles across), one of the co-orbital moons; Pandora (84 kilometers, 52 miles across), one of the F ring shepherding moons; and Enceladus (499 kilometers, 310 miles across), a moon which may be heated from within and thus have a liquid sub-surface ocean.

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 Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

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: CICLOPS News Release

Image credit: NASA/JPL
The international Cassini-Huygens mission is poised to begin an extensive tour of Saturn, its majestic rings and 31 known moons. After a nearly seven-year journey, Cassini is scheduled to enter orbit around Saturn at 7:30 p.m. PDT (10:30 p.m. EDT) June 30, 2004.

“The Saturn system represents an unsurpassed laboratory, where we can look for answers to many fundamental questions about the physics, chemistry and evolution of the planets and the conditions that give rise to life,” said Dr. Ed Weiler, associate administrator for space science at NASA Headquarters, Washington, D.C.

Launched Oct. 15, 1997, on a journey covering 3.5 billion kilometers (2.2 billion miles), Cassini is the most highly instrumented and scientifically capable planetary spacecraft ever flown. It has 12 instruments on the Cassini orbiter and six more on the Huygens probe. The mission represents the best technical efforts of 260 scientists from the United States and 17 European nations. The cost of the Cassini mission is approximately $3 billion.

The Cassini-Huygens mission is a four-year study of Saturn. The 18 highly sophisticated science instruments will study Saturn’s rings, icy satellites, magnetosphere and Titan, the planet’s largest moon.

For the critical Saturn orbit insertion maneuver, the spacecraft will fire its main engine for 96 minutes. The maneuver will reduce Cassini’s speed and allow it to be captured into orbit as a satellite of Saturn. Cassini will pass through a gap between two of Saturn’s rings, called the F and G rings. Cassini will swing close to the planet and begin the first of 76 orbits around the Saturn system. During Cassini’s four-year mission, it will execute 52 close encounters with seven of Saturn’s 31 known moons.

There are risks involved with orbit insertion, but mission planners have prepared for them. There is a backup engine in case the main engine fails. The region of passage through the ring plane was searched for hazards with the best Earth- and space-based telescopes.

Particles too small to be seen from Earth could be fatal to the spacecraft, so Cassini will be turned to use its high-gain antenna as a shield against small objects.

Saturn is the sixth planet from the sun. It is the second largest planet in our solar system, after Jupiter. The planet and its ring system serve as a miniature model for the disc of gas and dust surrounding the early Sun that formed the planets. Detailed knowledge of the dynamics of interactions among Saturn’s elaborate rings and numerous moons will provide valuable data for understanding how each of the solar system’s planets evolved.

The study of Titan, Saturn’s largest moon, is one of the major goals of the mission. Titan may preserve, in deep-freeze, many of the chemical compounds that preceded life on Earth. Cassini will execute 45 flybys of Titan, coming as close as approximately 950 kilometers (590 miles) above the surface. This will permit high-resolution mapping of the moon’s surface with an imaging radar instrument, which can see through the opaque haze of Titan’s upper atmosphere.

“Titan is like a time machine taking us to the past to see what Earth might have been like,” said Dr. Dennis Matson, Cassini project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “The hazy moon may hold clues to how the primitive Earth evolved into a life-bearing planet.”

On Dec. 25, 2004 (Dec. 24 in U.S. time zones) Cassini will release the wok-shaped Huygens probe on its journey toward Titan. Huygens will be the first probe to descend to the surface of a moon of another planet. It will also make the most distant descent by a robotic probe ever attempted on another object in the solar system. On Jan. 14, 2005, after a 20-day ballistic freefall, Huygens will enter Titan’s atmosphere. It will deploy parachutes and begin 2.5 hours of intensive scientific observations. The Huygens probe will transmit data to the Cassini spacecraft, which will relay the information back to Earth.

JPL designed, developed and assembled the Cassini orbiter. The European Space Agency managed the development of Huygens and is in charge of operations of the probe from its control center in Darmstadt, Germany. The Italian Space Agency provided the high-gain antenna, much of the radio system and elements of several of Cassini’s science instruments. JPL manages the overall program for NASA’s Office of Space Science, Washington, D.C.

For information about the Cassini-Huygens mission to Saturn and Titan on the Internet, visit: http://www.nasa.gov/cassini or http://www.esa.int/Cassini-Huygens.

Original Source: NASA/JPL News Release

Image credit: NASA/JPL/Space Science Institute
As Cassini coasts into the final month of its seven-year trek, the serene majesty of its destination looms ahead. The spacecraft’s cameras are functioning beautifully and continue to return stunning views from Cassini’s position, 1.2 billion kilometers (750 million miles) from Earth and now 15.7 million kilometers (9.8 million miles) from Saturn.

In this narrow angle camera image from May 21, 2004, the ringed planet displays subtle, multi-hued atmospheric bands, colored by yet undetermined compounds. Cassini mission scientists hope to determine the exact composition of this material.

This image also offers a preview of the detailed survey Cassini will conduct on the planet’s dazzling rings. Slight differences in color denote both differences in ring particle composition and light scattering properties.

Images taken through blue, green and red filters were combined to create this natural color view. The image scale is 132 kilometers (82 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 Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

Original Source: CICLOPS News Release

Image credit: NASA/JPL/Space Science Institute
Several dark spots, or storms, are huddled in the mid-latitude region of Saturn’s southern hemisphere. The largest of these storms is about 3000 kilometers (1860 miles) across, or about as wide as Japan is long. Also visible are light-colored, lacy cloud patterns indicative of atmospheric turbulence. The image was taken with the narrow angle camera through a near-infrared filter on May 7, 2004 from a distance of 28.2 million kilometers (17.5 million miles) from Saturn. Image scale is 168 kilometers (104 miles) per pixel. The image has been contrast-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 Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

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: CICLOPS News Release

Image credit: NASA
As Saturn grows closer through the eyes of the Cassini spacecraft, which is hurtling toward a rendezvous with the ringed world on June 30 (July 1, Universal Time), both Cassini and the Earth-orbiting Hubble Space Telescope snapped spectacular pictures of the planet and its magnificent rings.

Cassini is approaching Saturn at an oblique angle to the Sun and from below the ecliptic plane. Cassini has a very different view of Saturn than Hubble’s Earth-centered view. For the first time, astronomers can compare views of equal-sharpness of Saturn from two very different perspectives.

The view from Hubble, taken on March 22, 2004, is so sharp that many individual Saturnian ringlets can be seen. When Cassini returned its picture of Saturn on May 16, it was so close to the planet that the Imaging Science Subsystem narrow-angle camera could not fit the whole planet in its field-of-view. Cassini is still about 12.4 million miles (about 20 million kilometers) away and only 36 days from reaching Saturn.

Hubble’s exquisite optics, coupled with the high resolution of its Advanced Camera for Surveys, allow it to take pictures of Saturn which are nearly as sharp as Cassini’s, even though Hubble is nearly a billion miles farther from Saturn than Cassini. Cassini will ultimately far exceed the resolution of Hubble during its close encounter with Saturn. Cassini’s sharpness began to surpass Hubble’s when it came to within 14 million miles (23 million kilometers) of Saturn earlier this month.

Camera exposures in four filters (blue, blue-green, green, and red) were combined to form the Hubble image, to render colors similar to what the eye would see through a telescope focused on Saturn. The subtle pastel colors of ammonia-methane clouds trace a variety of atmospheric dynamics. Saturn displays its familiar banded structure, and haze and clouds of various altitudes. Like Jupiter, all bands are parallel to Saturn’s equator. Even the magnificent rings, at nearly their maximum tilt toward Earth, show subtle hues, which indicate the trace chemical differences in their icy composition.

Cassini has two cameras, a wide angle and narrow angle. This narrow angle image was made using a combination of three filters (red, green, blue) and was taken at a range of 15.1 million miles (24.3 million kilometers). The view is from 13 degrees below the equator. Enceladus, one of Saturn’s 31 known moons, appears near the south pole at the bottom of the image.

The differences between the Hubble and Cassini images are mainly due to the different sets of filters used.

Over two decades have passed since a spacecraft last visited Saturn ? NASA’s Voyager-2 flew by Saturn in August 1981. Since 1990, Hubble has produced high-resolution Saturn images, tracking storms and auroral activity while providing crisp views of the rings over time and from various angles.

Cassini will begin a four-year mission in orbit around Saturn when it arrives on June 30, 2004 PDT (July 1, 2004 UTC). Six months later it will release its piggybacked Huygens probe for descent through Titan’s thick atmosphere.

The Space Telescope Science Institute is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract with the Goddard Space Flight Center, Greenbelt, Md. The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. The Cassini-Huygens mission is a cooperative mission 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 mission for NASA’s Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.

Original Source: Hubble News Release

Image credit: NASA/JPL/Space Science Institute
The multitude of grooves for which Saturn’s rings are famed, clumps in the F ring, and several Saturnian moons are visible in this image. Moons visible in the image are: Mimas (398 kilometers, 247 miles across) above the rings at left; Epimetheus (116 kilometers, 72 miles across) just above the A ring ansa; Enceladus (499 kilometers, 310 miles across) near upper right. The image was taken with the narrow angle camera on May 10, 2004 at a distance of 27.1million kilometers (16.8 million miles) from Saturn. Image scale is 162 kilometers (101 miles) per pixel. Contrast in the image 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 Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

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

Image credit: NASA/JPL/Space Science Institute
Dramatic details are visible in the swirling turbulent bands of clouds in Saturn?s atmosphere. Particularly noteworthy is the disturbed equatorial region. The image was taken with the narrow angle camera in spectral region where methane strongly absorbs light on May 10, 2004 at a distance of 27.2 million kilometers (16.9 million miles) from Saturn. Image scale is 162 kilometers (101 miles) per pixel. Contrast in the image 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 Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

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: CICLOPS News Release