Prometheus Plays Tug of War with One of Saturn's Rings

The diminutive moon Prometheus whips gossamer ice particles out of Saturn's F ring in this image taken by the Cassini spacecraft on Aug. 21, 2009. The moon and the ring have eccentric, offset orbits, so Prometheus dips in and out of the F ring as it travels around Saturn. Its gravitational force drags the dust-sized particles at the edge of the F ring along for the ride.

The ability of the potato-shaped Prometheus to pull material out of the F ring was first theorized in the late 1990s and finally imaged by Cassini in 2004. But because these so-called "streamer-channels" have constantly shifted as Prometheus and the F ring have moved, the F ring has never looked the same twice. The gravitational pull of other moons on other rings has created waves in the edges, but nothing quite as extreme as the streamer-channels of Prometheus.

The Crab Nebula: A Cosmic Icon

A star's spectacular death in the constellation Taurus was observed on Earth as the supernova of 1054 A.D. Now, almost a thousand years later, a super dense object -- called a neutron star -- left behind by the explosion is seen spewing out a blizzard of high-energy particles into the expanding debris field known as the Crab Nebula. X-ray data from Chandra provide significant clues to the workings of this mighty cosmic "generator," which is producing energy at the rate of 100,000 suns.

This composite image uses data from three of NASA's Great Observatories. The Chandra X-ray image is shown in blue, the Hubble Space Telescope optical images are in yellow and red, and the Spitzer Space Telescope's infrared image is in purple. The X-ray image is smaller than the others because extremely energetic electrons emitting X-rays radiate away their energy more quickly than the lower-energy electrons emitting optical and infrared light. Along with many other telescopes, Chandra has repeatedly observed the Crab Nebula over the course of the mission’s lifetime. The Crab Nebula is one of the most studied objects in the sky, truly making it a cosmic icon.

Wise a Bit Closer to the Sky

NASA's Wide-field Infrared Survey Explorer, or Wise, is now perched atop its rocket at Vandenberg Air Force Base, north of Santa Barbara, Calif. The mission, which will scan the whole sky in infrared light, is scheduled to blast off on Dec. 9. It was hoisted to the top of its United Launch Alliance Delta II rocket on Friday, Nov. 20.

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The mission's principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

Cassini Sends Back Images of Enceladus as Winter Nears

NASA's Cassini spacecraft has sailed seamlessly through the Nov. 21 flyby of Saturn's moon Enceladus and started transmitting uncalibrated temperature data and images of the rippling terrain. These data and images will be processed and analyzed in the coming weeks. They will help scientists create the most-detailed-yet mosaic image of the southern part of the moon's Saturn-facing hemisphere and a contiguous thermal map of one of the intriguing "tiger stripe" features, with the highest resolution to date.

"These first raw images are spectacular, and paint an even more fascinating picture of Enceladus," said Bob Pappalardo, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The Cassini teams will be delving into the data to better understand the workings of this bizarre, active moon."

Scientists are particularly interested in the tiger stripes, which are fissures in the south polar region, because they spew jets of water vapor and other particles hundreds of kilometers, or miles, from the surface. This flyby was scientists' last peek at the tiger stripes before the south pole fades into the darkness of winter for several years. The thermal imaging work focused on the tiger stripe known as Baghdad Sulcus.

The Nov. 21 encounter, which is sometimes called "E8" because it is the eighth targeted flyby of Enceladus, brought Cassini to within about 1,600 kilometers (1,000 miles) of the moon's surface, at around 82 degrees south latitude. Cassini is now cruising toward Rhea, another one of Saturn's moons, for more imaging and mapping work.

Before Darkness Falls: Cassini to Scan Enceladus on Winter's Cusp

NASA's Cassini spacecraft will fly by Saturn's moon Enceladus this weekend for a last peek at the intriguing "tiger stripes" before winter darkness blankets the area for several years.

Scientists are particularly interested in the tiger stripes, which are fissures in the south polar region, because they spew jets of water vapor and other particles hundreds of kilometers, or miles, from the surface.

The flyby, which is sometimes called "E8" because it is the eighth targeted flyby of Enceladus, is scheduled for Saturday, Nov. 21 UTC, which is the evening of Friday, Nov. 20 in U.S. time zones. Cassini team members expect to fly the spacecraft to within about 1,600 kilometers (1,000 miles) of the moon's surface, at around 82 degrees south latitude. This will be a more distant flyby than the one on Nov. 2, when Cassini flew about 100 kilometers (60 miles) above the surface.

During this flyby, scientists will focus on a tiger stripe called Baghdad Sulcus and create a contiguous thermal map of the feature. The spacecraft will also be snapping high-resolution images of the southern part of the Saturn-facing hemisphere.

NASA and Microsoft Allow Earthlings to Become Martians

NASA and Microsoft Corp. of Redmond, Wash., have collaborated to create a Web site where Internet users can have fun while advancing their knowledge of Mars.

Drawing on observations from NASA’s Mars missions, the "Be a Martian" Web site will enable the public to participate as citizen scientists to improve Martian maps, take part in research tasks, and assist Mars science teams studying data about the Red Planet.

"We're at a point in history where everyone can be an explorer," said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington. "With so much data coming back from Mars missions that are accessible by all, exploring Mars has become a shared human endeavor. People worldwide can expand the specialized efforts of a few hundred Mars mission team members and make authentic contributions of their own."

Participants will be able to explore details of the solar system's grandest canyon, which resides on Mars. Users can call up images in the Valles Marineris canyon before moving on to chart the entire Red Planet. The collaboration of thousands of participants could assist scientists in producing far better maps, enabling smoother zoom-in views and easier interpretation of Martian surface changes.

By counting craters, the public also may help scientists determine the relative ages of small regions on Mars. In the past, counting Martian craters has posed a challenge because of the vast numbers involved. By contributing, Web site users will win game points assigned to a robotic animal avatar they select.

With a common goal of inspiring digital-age workforce development and life-long learning in science, technology, engineering and mathematics, NASA and Microsoft unveiled the Web site at the Microsoft Professional Developers Conference in Los Angeles this week. The site also beckons software developers to win prizes for creating tools that provide access to and analysis of hundreds of thousands of Mars images for online, classroom and Mars mission team use.

"Industry leaders like NASA and Microsoft have a social responsibility as well as a vested interest in advancing science and technology education," said Walid Abu-Hadba, corporate vice president of the Developer and Platform Evangelism Group at Microsoft. "We are excited to be working with NASA to provide new opportunities to engage with Mars mission data, and to help spark interest and excitement among the next generation of scientists and technologists."

To encourage more public participation, the site also provides a virtual town hall forum where users can expand their knowledge by proposing Mars questions and voting on which are the most interesting to the community. Online talks by Mars experts will address some of the submitted questions. Other features include interactive tools for viewing Martian regions and movies about people who study Mars in diverse ways.

"Mars exploration inspires people of all ages, and we are especially eager to encourage young people to explore Mars for themselves," said Charles Elachi, director of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We are delighted to be involved in providing the creative opportunity for future explorers to contribute to our understanding of Mars."

"The beauty of this type of experience is that it not only teaches people about Mars and the work NASA is doing there, but it also engages large groups of people to help solve real challenges that computers cannot solve by themselves," said Marc Mercuri, director of business innovation in the Developer and Platform Evangelism Group at Microsoft.

LCROSS Impact Data Indicates Water on Moon

The argument that the moon is a dry, desolate place no longer holds water.

Secrets the moon has been holding, for perhaps billions of years, are now being revealed to the delight of scientists and space enthusiasts alike.

NASA today opened a new chapter in our understanding of the moon. Preliminary data from the Lunar CRater Observation and Sensing Satellite, or LCROSS, indicates that the mission successfully uncovered water during the Oct. 9, 2009 impacts into the permanently shadowed region of Cabeus cater near the moon’s south pole.

The impact created by the LCROSS Centaur upper stage rocket created a two-part plume of material from the bottom of the crater. The first part was a high angle plume of vapor and fine dust and the second a lower angle ejecta curtain of heavier material. This material has not seen sunlight in billions of years.

"We're unlocking the mysteries of our nearest neighbor and by extension the solar system. It turns out the moon harbors many secrets, and LCROSS has added a new layer to our understanding," said Michael Wargo, chief lunar scientist at NASA Headquarters in Washington.

Scientists have long speculated about the source of vast quantities of hydrogen that have been observed at the lunar poles. The LCROSS findings are shedding new light on the question of water, which could be more widespread and in greater quantity than previously suspected.

Permanently shadowed regions could hold a key to the history and evolution of the solar system, much as an ice core sample taken on Earth reveals ancient data. In addition, water, and other compounds represent potential resources that could sustain future lunar exploration.