NASA Cassini Spacecraft Buzzes Saturn's Moon Titan's Methane Lake

NASA's Cassini probe zipped by Saturn's largest moon Titan on Tuesday (July 24) in a close flyby to search for a lake filled with liquid methane.

The Cassini spacecraft flew within 629 miles (1,012 kilometers) of Titan during the flyby in order to "look for a glint of sunlight reflecting off a methane lake," mission managers wrote in a statement.

Scientists have dubbed the liquid methane lake Kivu Lacus. It is one of the small northern lakes on Titan and Cassini mission scientists hoped to use the spacecraft's visible and infrared mapping spectrometer (or VIMS) to glean new details about the lake by analyzing its reflected light.

NASA Saturn's Titan: Cassini spots tropical lagoons of Methane

Tropical lakes observed by Cassini. Credit: NASA

Planetary scientists have been surprised by the discovery of exotic lagoons in the tropics of Saturn's largest moon Titan.

These are not sun-kissed holiday spots however, but long-standing little lakes of methane beneath the satellites poisonous smog.

They come as a surprise because it had been thought that such wet areas would be found only around the poles due to circulation patterns within Titan's atmosphere.

Titan fascinates because, despite the unfriendly nature of its chemistry, it shows remarkable similarities to surface features and weather on our own planet.

This is largely because this distant moon is the only satellite in the Solar System to have a dense atmosphere. There it rains methane rather than water, with the liquid circulating in a way similar to the Earth's hydrological cycle.

Europe achieved a major space success in 2005 with the soft-landing of a space probe, Huygens, which had been carried there by NASA's Cassini mission to Saturn. The lander sent back pictures and other data about the region where it landed that suggested it might be a damp former lake bed with a consistency similar to creme brulee.

ESA Saturn Titan: Far-off cousin of part-time African lake found on Titan

A region on Saturn’s moon Titan has been found to be similar to the Etosha Pan in Namibia, Africa. Both are ephemeral lakes – large, shallow depressions that sometimes fill with liquid.

Ontario Lacus is the largest lake in the southern hemisphere of Saturn’s moon, Titan. It is a little smaller than its namesake, Lake Ontario in North America, but otherwise differs from it in some major ways.

It is filled with liquid hydrocarbons, not water, and it is only a few metres deep at most, located in an extremely shallow depression in a flat sedimentary basin, surrounded by small mountain ranges.

In addition, a new study shows that these landforms and the climatic conditions in the region are similar to those of semi-arid regions on Earth, such as the salt pans of southern Africa.

The observations were made by the Cassini orbiter, part of the NASA, ESA and Italian Space Agency Cassini–Huygens mission to Saturn’s system.

While Ontario Lacus was previously thought to be permanently filled with liquid methane, ethane and propane, these latest observations, published in the journal Icarus, suggest otherwise.

By combining data from Cassini’s imaging, spectroscopic and radar instruments – each of which observed Ontario Lacus twice – scientists led by Thomas Cornet of the Université de Nantes, France, found evidence for channels etched into the lake bed within the southern boundary of the depression. These channels remained visible between December 2007 and January 2010, each time the spatial resolution was able to resolve them.

“We conclude that the solid floor of Ontario Lacus is most probably exposed in those areas,” says Cornet.

In addition, Cassini shows sediments around Ontario Lacus that also indicate the liquid level has been higher in the past.

This is similar to ephemeral lakes on Earth. The researchers suggest its nearest cousin is the Etosha Pan in Namibia. This salt lake bed fills with a shallow layer water, provided by the rise of the underground aquifer during the rainy season, before evaporating to leave sediments like tide marks showing the previous extent of the water.

Cornet and colleagues thus believe that Ontario Lacus is also the result of subsurface hydrocarbon fluids occasionally welling up and flooding the depression, before then partially drying out again.

Beyond Earth, Titan is the only other world known to bear stable liquids on its surface. Where Earth has a water cycle, Titan has a full hydrocarbon cycle, based on hydrogen, carbon and nitrogen, taking place between the atmosphere, the surface and the subsurface. Titan’s lakes are an integral part of this process.

“These results emphasise the importance of comparative planetology in modern planetary sciences: finding familiar geological features on alien worlds like Titan allows us to test the theories explaining their formation,” says Nicolas Altobelli, ESA’s Cassini–Huygens project scientist.

NASA Launch new concept: Sailing on an Extraterrestrial Sea

Many of us have sailed the Earth's lakes, bays and rivers. But, imagine sailing on an extraterrestrial sea of liquid methane-ethane a billion miles from Earth.

This is the kind of idea that makes science fiction so interesting. Yet, this may not be fiction at all.

Under its Discovery Program NASA is currently conducting a contest among three science teams. One team will be selected for a 2016 mission.

Possible choices are

(1) investigation of the interior of Mars for the first time,

(2) measurement of the environmental factors on one of Titan's oceans and

(3) study the surface of a comet's nucleus in great detail.

Well. We have been to Mars many times and we have studied comets at length in recent years. But, we have never placed an Earth-made spacecraft on a sea outside the earth's environment, let alone on a moon of Saturn. Wow!

TiME, the Titan Mare Explorer, is designed to do just that. If selected by NASA, a U.S. science and mission team will develop a small interplanetary spacecraft that can travel from Earth to Saturn.

As it approaches this outer planet, about a billion miles from earth, TiME will be targeted to make a direct entry into Titan's atmosphere. After initial entry a series of parachutes will lower the spacecraft to a slow splashdown on Ligeia Mare (78 degrees N, 250 degrees W), one of the largest known lakes of Titan with a surface area of about 100,000 km".

Liftoff from Earth would take place in 2016 and TiME would splashdown in 2023. Science objectives on Titan include determining the chemistry and depth of the sea, how the local meteorology varies on diurnal timescales and properties of the atmosphere above the sea.

Titan's thick atmosphere and the sun's distance rule out the use of solar panels. Thus, TiME would be the test flight for the new Advanced Stirling Radioisotope Generator (ASRG).

TiME will communicate directly with Earth until 2026, when Earth finally sinks below the horizon as seen from Ligeia. Earthrise will occur again in 2035.

Cassini Solstice Mission: Titan's Kraken Mare

The Cassini spacecraft looks toward Saturn's largest moon, Titan, and spies the huge Kraken Mare in the moon's north.

Kraken Mare, a large sea of liquid hydrocarbons, is visible as a dark area near the top of the image.

See Titan's Northern Polar Clouds and Titan's Northern Lake to learn more.

This view looks toward the Saturn-facing side of Titan (3,200 miles across, or 5,150 kilometers,).

North on Titan is up and rotated 29 degrees to the left.

The image was taken with the Cassini spacecraft narrow-angle camera on Sept. 14, 2011 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers.

The view was acquired at a distance of approximately 1.2 million miles (1.9 million kilometers) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 26 degrees. Image scale is 7 miles (12 kilometers) 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 mission for NASA's Science Mission Directorate in Washington.

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 or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org .

Credit: NASA/JPL-Caltech/Space Science Institute

NASA JPL: Giant ice volcano found on Titan

A potential new ice volcano has been found on Saturn's moon Titan.

Named Sotra, the volcano is nearly 1 kilometre tall and has a 1.6-kilometre-deep pit alongside it.

Surrounded by giant sand dunes, it is thought to be the largest in a string of several volcanoes that once spewed molten ice from deep beneath the moon's surface.

"We think we have found the strongest case yet for an ice volcano on Titan," said Randy Kirk, a geophysicist at the US Geological Survey in Flagstaff, Arizona. "What we see is not just a flow like we see in other places, it's like a volcanic field would be on Earth."

Titan is about the size of the planet Mercury but has an atmosphere thicker than Earth's. This makes it incredibly difficult for astronomers to know what's happening on the surface. Planetary scientists, including Kirk, are using NASA's Cassini spacecraft to map the moon, but so far only about half of Titan has been imaged.

Kirk and his team created a 3D mapping technique that patches together multiple images of the same area, so they were lucky that Sotra was in one of the rare places imaged twice.

"The classical volcano everybody thinks of when you say the word is a mountain with a crater on it and lava flows coming out of it," said Kirk. "That's what we've found on Titan."
'This is it'

The team cannot be certain if the chain is active, but described the find as the best evidence found so far for a cryovolcano, or ice volcano. Previously, bright spots seen in low-resolution satellite images have been interpreted as volcanic flows and craters. However, once those areas were mapped in 3D, it became obvious they weren't volcanoes.

"We had noted Sotra Facula as a candidate cryovolcano before," said Rosaly Lopes at NASA's Jet Propulsion Laboratory in Pasadena, California. "But it was only when Randy got the topography done that we realised, wow, this is it."

Earth's interior is divided into distinct layers of rock and liquid magma. When this molten rock erupts through the planet's crust, it's known as volcanism. Titan's volcanism is more complicated because beneath the moon's surface lies a layer of ice. Even a small amount of internal heat could create molten ices. Because the liquid would be less dense, it would force its way to the surface. The result would be a massive eruption of slushy liquid and gases similar to what scientists have seen on other icy moons.

"Ice at outer solar system temperatures is very rigid," Kirk said. "Ice at close to its melting point is soft. What would be a glacier on Earth would be a volcano on a body that's made of that same material. It's the difference between the cake and the frosting."



Giant ice volcano may have been found on Titan - space - 14 December 2010 - New Scientist

NASA Cassini spacecraft: Saturn's Moon Titan's North Polar Region

NASA's Cassini spacecraft will be eyeing the north polar region of Saturn's moon Titan this weekend, scanning the moon's land o' lakes.

At closest approach on early morning Saturday, June 5 UTC, which is Friday afternoon, June 4 Pacific time, Cassini will glide to within about 2,000 kilometers (1,300 miles) of the Titan surface.

Cassini will make infrared scans of the north polar region, which was in darkness for the first several years of Cassini's tour around the Saturn system. The lighting has improved as northern spring has started to dawn over the area.

The visual and infrared spectrometer will be prime during closest approach, but the imaging science subsystem cameras will also be taking pictures. Among the scientific bounties, Cassini team members are hoping to get another good look at Kraken Mare, the largest lake on Titan, which covers a greater area than the Caspian Sea on Earth.

Although this latest flyby is dubbed "T69," planning changes early in the orbital tour made this the 70th targeted flyby of Titan.

ESA Casini: Reflection of Sunlight off Titan Lake

This image shows the first flash of sunlight reflected off a lake on Saturn’s moon Titan.

The glint off a mirror-like surface is known as a specular reflection. This kind of glint was detected by the visual and infrared mapping spectrometer (VIMS) on NASA’s Cassini spacecraft on July 8, 2009.

It confirmed the presence of liquid in the moon’s northern hemisphere, where lakes are more numerous and larger than those in the southern hemisphere.

Scientists using VIMS had confirmed the presence of liquid in Ontario Lacus, the largest lake in the southern hemisphere, in 2008.

The northern hemisphere was shrouded in darkness for nearly 15 years, but the sun began to illuminate the area again as it approached its spring equinox in August 2009. VIMS was able to detect the glint as the viewing geometry changed.

Titan’s hazy atmosphere also scatters and absorbs many wavelengths of light, including most of the visible light spectrum. But the VIMS instrument enabled scientists to look for the glint in infrared wavelengths that were able to penetrate through the moon’s atmosphere. This image was created using wavelengths of light in the 5 micron range.

By comparing the new image to radar and near-infrared light images acquired from 2006 to 2008, Cassini scientists were able to correlate the reflection to the southern shoreline of a Titan lake called Kraken Mare.

The sprawling Kraken Mare covers about 400,000 square kilometers (150,000 square miles). The reflection appeared to come from a part of the lake around 71 degrees north latitude and 337 degrees west latitude.

It was taken on Cassini’s 59th flyby of Titan on July 8, 2009, at a distance of about 200,000 kilometers (120,000 miles). The image resolution was about 100 kilometers (60 miles) per pixel. Image processing was done at the German Aerospace Center in Berlin and the University of Arizona in Tucson.

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 mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The visual and infrared mapping spectrometer team is based at the University of Arizona, Tucson.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping spectrometer team homepage is at http://wwwvims.lpl.arizona.edu/.