Closest Northern Views of Saturn's Moon Enceladus

NASA's Cassini spacecraft has begun returning its best-ever views of the northern extremes of Saturn's icy, ocean-bearing moon Enceladus. The spacecraft obtained the images during its Oct. 14 flyby, passing 1,142 miles (1,839 kilometers) above the moon's surface. Mission controllers say the spacecraft will continue transmitting images and other data from the encounter for the next several days.

Scientists expected the north polar region of Enceladus to be heavily cratered, based on low-resolution images from the Voyager mission, but the new high-resolution Cassini images show a landscape of stark contrasts. "The northern regions are crisscrossed by a spidery network of gossamer-thin cracks that slice through the craters," said Paul Helfenstein, a member of the Cassini imaging team at Cornell University, Ithaca, New York. "These thin cracks are ubiquitous on Enceladus, and now we see that they extend across the northern terrains as well."

In addition to the processed images, unprocessed, or "raw," images are posted on the Cassini mission website at:

http://saturn.jpl.nasa.gov/mission/flybys/enceladus20151014

Cassini's next encounter with Enceladus is planned for Oct. 28, when the spacecraft will come within 30 miles (49 kilometers) of the moon's south polar region. During the encounter, Cassini will make its deepest-ever dive through the moon's plume of icy spray, sampling the chemistry of the extraterrestrial ocean beneath the ice. Mission scientists are hopeful data from that flyby will provide evidence of how much hydrothermal activity is occurring in the moon's ocean, along with more detailed insights about the ocean's chemistry -- both of which relate to the potential habitability of Enceladus.

Cassini's final close Enceladus flyby will take place on Dec. 19, when the spacecraft will measure the amount of heat coming from the moon's interior. The flyby will be at an altitude of 3,106 miles (4,999 kilometers).

Saturnian Snowman

NASA's Cassini spacecraft spied this tight trio of craters as it approached Saturn's icy moon Enceladus for a close flyby on Oct. 14, 2015.

Credits: NASA/JPL-Caltech/Space Science Institute

Full image and caption

An online toolkit for all three final Enceladus flybys is available at:

http://solarsystem.nasa.gov/finalflybys

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena, California, manages the mission for the agency's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena. The Cassini imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about Cassini, visit:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

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Swilling Stormy Stars present on cool celestial orbs

Swirling, stormy clouds may be ever-present on cool celestial orbs called brown dwarfs. New observations from NASA's Spitzer Space Telescope suggest that most brown dwarfs are roiling with one or more planet-size storms akin to Jupiter's "Great Red Spot." "As the brown dwarfs spin on their axis, the alternation of what we think are cloud-free and cloudy regions produces a periodic brightness variation that we can observe," said Stanimir Metchev of the University of Western Ontario, Canada. "These are signs of patchiness in the cloud cover."

In a Spitzer program named "Weather on Other Worlds," astronomers used the infrared space telescope to watch 44 brown dwarfs as they rotated on their axis for up to 20 hours. Previous results had suggested that some brown dwarfs have turbulent weather, so the scientists had expected to see a small fraction vary in brightness over time. However, to their surprise, half of the brown dwarfs showed the variations. When you take into account that half of the objects would be oriented in such a way that their storms would be either hidden or always in view and unchanging, the results indicate that most, if not all, brown dwarfs are racked by storms.

"We needed Spitzer to do this," said Metchev. "Spitzer is in space, above the thermal glow of the Earth's atmosphere, and it has the sensitivity required to see variations in the brown dwarfs' brightness."

The results led to another surprise as well. Some of the brown dwarfs rotated much more slowly than any previously measured, a finding that could not have been possible without Spitzer's long, uninterrupted observations from space. Astronomers had thought that brown dwarfs sped up to very fast rotations when they formed and contracted, and that this rotation didn't wind down with age.

"We don't yet know why these particular brown dwarfs spin so slowly, but several interesting possibilities exist," said Heinze.  "A brown dwarf that rotates slowly may have formed in an unusual way -- or it may even have been slowed down by the gravity of a yet-undiscovered planet in a close orbit around it."

The work may lead to a better understanding of not just brown dwarfs but their "little brothers": the gas-giant planets. Researchers say that studying the weather on brown dwarfs will open new windows onto weather on planets outside our solar system, which are harder to study under the glare of their stars. Brown dwarfs are weather laboratories for planets, and, according to the new results, those laboratories are everywhere.

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Cassini Sees Saturn and Moons - Nasa Space News

"During this, our tenth holiday season at Saturn, we hope that these images from Cassini remind everyone the world over of the significance of our discoveries in exploring such a remote and beautiful planetary system," said Carolyn Porco, Cassini imaging team leader, based at the Space Science Institute, Boulder, Colo. "Happy holidays from all of us on Cassini."

Two views of Enceladus are included in the package and highlight the many fissures, fractures and ridges that decorate the icy moon's surface. Enceladus is a white, glittering snowball of a moon, now famous for the nearly 100 geysers that are spread across its south polar region and spout tiny icy particles into space. Most of these particles fall back to the surface as snow. Some small fraction escapes the gravity of Enceladus and makes its way into orbit around Saturn, forming the planet's extensive and diffuse E ring. Because scientists believe these geysers are directly connected to a subsurface, salty, organic-rich, liquid-water reservoir, Enceladus is home to one of the most accessible extraterrestrial habitable zones in the solar system.

Packaged along with Saturn and Enceladus is a group of natural-color images of Saturn's largest moon, Titan, highlighting two of Titan's most outstanding features. Peering through the moon's hazy, orange atmosphere, the Cassini narrow-angle camera spots dark, splotchy features in the polar regions of the moon. These features are the lakes and seas of liquid methane and ethane for which the moon is renowned. Titan is the only other place in the solar system that we know has stable liquids on its surface, though in Titan's case, the liquids are ethane and methane rather than water. At Titan's south pole, a swirling high-altitude vortex stands out distinctly against the darkness of the moon's un-illuminated atmosphere. Titan's hazy atmosphere and surface environment are believed to be similar in certain respects to the early atmosphere of Earth.

"Until Cassini arrived at Saturn, we didn't know about the hydrocarbon lakes of Titan, the active drama of Enceladus' jets, and the intricate patterns at Saturn's poles," said Linda Spilker, the Cassini project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Spectacular images like these highlight that Cassini has given us the gift of knowledge, which we have been so excited to share with everyone." Launched in 1997, Cassini has explored the Saturn system for more than nine years. NASA plans to continue the mission through 2017, with the anticipation of much more groundbreaking science and imagery to come.

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Hubble Digs Up Galactic Glow Worm

This charming and bright galaxy, known as IRAS 23436+5257, was captured by the NASA/ESA Hubble Space Telescope. It is located in the northern constellation of Cassiopeia, which is named after an arrogant, vain, and yet beautiful mythical queen.

Hubble Digs Up Galactic Glow Worm

The twisted, wormlike structure of this galaxy is most likely the result of a collision and subsequent merger of two galaxies. Such interactions are quite common in the universe, and they can range from minor interactions involving a satellite galaxy being caught by a spiral arm, to major galactic crashes. Friction between the gas and dust during a collision can have a major effect on the galaxies involved, morphing the shape of the original galaxies and creating interesting new structures.

When you look up at the calm and quiet night sky it is not always easy to picture it as a dynamic and vibrant environment with entire galaxies in motion, spinning like children’s toys and crashing into whatever crosses their path. The motions are, of course, extremely slow, and occur over millions or even billions of years.

The aftermath of these galactic collisions helps scientists to understand how these movements occur and what may be in store for our own Milky Way, which is on a collision course with a neighboring galaxy, Messier 31

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The F-1 Engine Powered Apollo Into History

The F-1 engine -- the most powerful single-nozzle, liquid fueled rocket engine ever developed -- boosted the Saturn V rocket off the launch pad and onto the moon during NASA's Apollo program during the 1960s and 1970.


Five F-1 engines were used in the 138-foot-tallS-IC, or first stage, of each Saturn V, which depended on the five-engine cluster for the 7.5 million pounds of thrust needed to lift it from the launch pad. The mighty engines, developed by engineers at NASA's Marshall Space Flight Center and its industry team, were fueled by a mixture of liquid oxygen and kerosene.

The cluster of five F-1 engines burned more than 15 metric tons of propellant per second during its two-and-one-half-minutes of operation. Each F-1 engine had more thrust than three space shuttle main engines combined to lift the vehicle to a height of about 36 miles and to a speed of about 6,000 mph.

The F-1 engine had roots outside NASA, born as an Air Force program developed by the aerospace firm Rocketdyne in 1955. NASA inherited it during a transfer of projects, conducted its own feasibility studies and awarded Rocketdyne a follow-on contract to step up work on the gargantuan propulsion system not long after NASA's formation, in 1960.

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Young Stars at Home in Ancient Cluster

NGC 6752 contains a high number of "blue straggler'' stars, some of which are visible in this image. These stars display characteristics of stars younger than their neighbors, despite models suggesting that most of the stars within globular clusters should have formed at approximately the same time. Their origin is therefore something of a mystery.

The above image looks like a hoard of gems fit for an emperor's collection, this deep sky object called NGC 6752 is in fact far more worthy of admiration. It is a globular cluster, and at over 10 billion years old is one the most ancient collections of stars known. It has been blazing for well over twice as long as our solar system has existed.

Studies of NGC 6752 may shed light on this situation. It appears that a very high number -- up to 38 percent -- of the stars within its core region are binary systems. Collisions between stars in this turbulent area could produce the blue stragglers that are so prevalent.

Lying 13,000 light-years distant, NGC 6752 is far beyond our reach, yet the clarity of Hubble's images brings it tantalizingly close.

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Confirm Designs For Mobile Launcher Tests

The 355-foot-tall Mobile Launcher, or ML, behaved as expected during its move to Launch Pad 39B in November 2011, an analysis of multiple sensors showed. The top of the tower swayed less than an inch each way. The tests showed that computer models used in designing the massive structure were correct. The actual results varied less than 5 percent of what was predicted.

"This gives us much higher confidence in the models," Brown said. "We know that our approach is valid."

Engineers had the tower wired with dozens of accelerometers and strain gauges along with wind sensors to record the launcher's movement during its slow ride atop a crawler-transporter from a park site beside the Vehicle Assembly Building to the launch pad. Crawler drivers performed several speed changes during the six-mile journeys to and from the pad. While at the pad, which is being refurbished after decades of hosting space shuttles, workers connected ventilation, fire support and alarm systems and other water lines.

"We were measuring milli-g's," Brown said.

The ML, designed for the Ares I rocket of the cancelled Constellation program, is due for major modifications in the coming few years as it is strengthened to support the much-heavier SLS. It took two years to build and was completed in August 2010. The ML is the biggest structure of its kind since the Launch Umbilical Towers were constructed to support the Apollo/Saturn V. Those towers saw numerous modifications through their lives as trial-and-error showed where changes were needed, Brown said.

"Our goal here is to have less of those kinds of problems," Brown said.

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