'S' is for Space Station

Astronauts aboard the International Space Station are helping children learn their ABC's and vocabulary through educational demonstrations of how they live and work in space.

NASA collaborated with Sesame Workshop, including the popular children’s television programs, "Sesame Street" and "The Electric Company," to create science, technology, engineering and math-related education resources, or STEM, for children ages 2-5.

"The space station environment provides a unique classroom in space to teach young children about the words such as 'float' and 'astronaut' by showing them how astronauts float in space," said Matthew Keil in the Teaching from Space Office at NASA's Johnson Space Center in Houston.


Space station astronaut Soichi Noguchi completed four educational videos for "Sesame Street" during his stay on the International Space Station from December 2009 to June 2010. The four videos are airing on "Sesame Street" throughout the fall 2010 season. On the episode "F is for Float" -- show number 4214 -- Noguchi held up the letter "F" to represent the word "float" while he floated around the space station to demonstrate the word.

"Word on the Street" -- show number 4222 -- featured Noguchi explaining to the character "Murray" what the word "float" means, using similar demonstrations with a lemon, socks and a ball.

On the episode "A is for Astronaut" -- show number 4225 -- Noguchi held up the letter "A" to represent the word "astronaut." Noguchi sounded out the letter and the word for children.

On the "Countdown to Space" episode -- show number 4234 airing on PBS December 27 -- Noguchi counted down from 10 to one. Noguchi counted down and said "blast-off!" while floating from the floor to the ceiling.

Sesame Workshop approached the NASA Teaching from Space Office for assistance in implementing more science and math curriculum into their programming by using the unique educational environment of the space station, NASA centers and facilities and the unique people who work at NASA.

"I am an educator who is very interested in making connections between curriculum and everyday life experiences that students encounter," said Keil. "There are many teachable moments that exist in every NASA mission. Our job is to make sure educators and students are aware of these moments and assist them in connecting these moments to what they are teaching or learning in school and at home."

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Where Over the World is Commander Scott Kelly?

Commander Scott Kelly is living off the planet aboard the International Space Station for a period of nearly six months. Traveling the world more than 230 miles above Earth and at 17,500 mph, he circumnavigates the globe more than a dozen times a day. During his stay on station, he will have opportunities to see and photograph various geographical locations on Earth from space. In fact, part of his job while in space will be to capture a kaleidoscope of geographical spots for Earth scientific observations.

› View the Geography Trivia Contest Winners page
› Read the press release

Through these snapshots, Commander Kelly will share his view from space and also engage the public by way of a virtual journey around the world via a geography trivia game on Twitter.


How to play: Users follow @StationCDRKelly, who will tweet from space a photo during the Expedition 25/26 flight. The first person to @reply to @StationCDRKelly with the correct answer wins. Use the hashtag #spacegeo after your reply and to follow the geography game on Twitter from space. Players are competing to be the first to name that inkblot of Earth from space to win a printed photo of the shot taken from space and autographed by astronaut Kelly after his return to Earth. At the end of each week, the trivia photo will be posted to nasa.gov along with the winner’s name.

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A Galaxy for Everyone

This collage of galaxies from NASA's Wide-Field Infrared Survey Explorer, or WISE, showcases the many "flavors" that galaxies come in, from star-studded spirals to bulging ellipticals to those paired with other companion galaxies. The WISE team put this collage together to celebrate the anniversary of the mission's launch on Dec. 14, 2009.

After launch and a one-month checkout period, WISE began mapping the sky in infrared light. By July of this year, the entire sky had been surveyed, detecting hundreds of millions of objects, including the galaxies pictured here. In October of this year, after scanning the sky about one-and–a-half times, the spacecraft ran out of its frozen coolant, as planned. With its two shortest-wavelength infrared detectors still operational, the mission continues to survey the sky, focusing primarily on asteroids and comets.

NGC 300 is seen in the image in the upper left panel. This is a textbook spiral galaxy. In fact, it is such a good representation of a spiral galaxy that astronomers have studied it in great detail to learn about the structure of all spirals in general. Infrared images like this one from WISE show astronomers where areas of gas and warm dust are concentrated -- features that cannot be seen in visible light. At about 39,000 light-years across, NGC 300 is only about 40 percent the size of the Milky Way galaxy.

The upper right image shows Messier 104, or M104, also known as the Sombrero galaxy. Although M104 is also classified as a spiral galaxy, it has a very different appearance than NGC 300. In part, this is because the dusty, star-forming spiral disk in M104 is seen nearly edge-on from our point of view. M104 also has a large, ball-shaped bulge component of older stars, seen here in blue.

The large, fuzzy grouping of stars at the center of the lower left panel is the galaxy Messier 60, or M60. This galaxy does not have a spiral disk, just a bulge, making it a massive elliptical galaxy. M60 is about 20 percent larger than our Milky Way galaxy, and lies in the Virgo cluster of galaxies. The brighter, dense spot inside but off-center from the blue core of M60 is a separate spiral galaxy called NGC 4647. In addition, two different asteroids were caught crossing the field of view when WISE imaged this portion of the sky (seen as dotted green lines extending out from M60 at about the 2 o'clock and 8 o'clock positions).

The galaxy in the lower right panel is Messier 51, or NGC 5194, also frequently referred to as the Whirlpool galaxy. The Whirlpool is a "grand design" spiral galaxy. It is interacting with its smaller companion -- NGC 5195, a dwarf galaxy, which can be seen as a bright spot near the tip of the spiral arm extending up and to the right of the Whirlpool galaxy.

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Mars Movie - I'm Dreaming of a Blue Sunset

A new Mars movie clip gives us a rover's-eye view of a bluish Martian sunset, while another clip shows the silhouette of the moon Phobos passing in front of the sun.

America's Mars Exploration Rover Opportunity, carefully guided by researchers with an artistic sense, has recorded images used in the simulated movies.

These holiday treats from the rover's panoramic camera, or Pancam, offer travel fans a view akin to standing on Mars and watching the sky.

"These visualizations of an alien sunset show what it must have looked like for Opportunity, in a way we rarely get to see, with motion," said rover science team member Mark Lemmon of Texas A&M University, College Station. Dust particles make the Martian sky appear reddish and create a bluish glow around the sun.

Lemmon worked with Pancam Lead Scientist Jim Bell, of Cornell University, Ithaca, N.Y., to plot the shots and make the moving-picture simulation from images taken several seconds apart in both sequences.

The sunset movie, combining exposures taken Nov. 4 and Nov. 5, 2010, through different camera filters, accelerates about 17 minutes of sunset into a 30-second simulation. One of the filters is specifically used to look at the sun. Two other filters used for these shots provide color information. The rover team has taken Pancam images of sunsets on several previous occasions, gaining scientifically valuable information about the variability of dust in the lower atmosphere. The new clip is the longest sunset movie from Mars ever produced, taking advantage of adequate solar energy currently available to Opportunity.


The two Martian moons are too small to fully cover the face of the sun, as seen from the surface of Mars, so these events -- called transits or partial eclipses -- look quite different from a solar eclipse seen on Earth. Bell and Lemmon chose a transit by Phobos shortly before the Mars sunset on Nov. 9, 2010, for a set of Pancam exposures taken four seconds apart and combined into the new, 30-second, eclipse movie. Scientifically, images years apart that show Phobos' exact position relative to the sun at an exact moment in time aid studies of slight changes in the moon's orbit. This, in turn, adds information about the interior of Mars.

The world has gained from these movies and from more than a quarter million other images from Opportunity and its twin, Spirit, since they landed on Mars in January 2004. Those gains go beyond the facts provided for science.

Bell said, "For nearly seven years now, we've been using the cameras on Spirit and Opportunity to help us experience Mars as if we were there, viewing these spectacular vistas for ourselves. Whether it's seeing glorious sunsets and eclipses like these, or the many different and lovely sandy and rocky landscapes that we've driven through over the years, we are all truly exploring Mars through the lenses of our hardy robotic emissaries.

"It reminds me of a favorite quote from French author Marcel Proust: 'The real voyage of discovery consists not in seeking new landscapes, but in having new eyes,'" he added.

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Cassini Finishes Sleigh Ride by Icy Moons

On the heels of a successful close flyby of Saturn's moon Enceladus, NASA's Cassini spacecraft is returning images of Enceladus and the nearby moon Dione.

Several pictures show Enceladus backlit, with the dark outline of the moon crowned by glowing jets from the south polar region. The images show several separate jets, or sets of jets, emanating from the fissures known as "tiger stripes." Scientists will use the images to pinpoint the jet source locations on the surface and learn more about their shape and variability.

The Enceladus flyby took Cassini within about 48 kilometers (30 miles) of the moon's northern hemisphere. Cassini's fields and particles instruments worked on searching for particles that may form a tenuous atmosphere around Enceladus. They also hope to learn whether those particles may be similar to the faint oxygen- and carbon-dioxide atmosphere detected recently around Rhea, another Saturnian moon. The scientists were particularly interested in the Enceladus environment away from the jets emanating from the south polar region. Scientists also hope this flyby will help them understand the rate of micrometeoroid bombardment in the Saturn system and get at the age of Saturn's main rings.

This flyby of Enceladus, the 13th in Cassini's mission, took a similar path to the last Enceladus flyby on Nov. 30. About eight hours before the Enceladus flyby, Cassini also swung past Dione at a distance of about 100,000 kilometers (62,000 miles). During that flyby, the spacecraft snapped clear, intriguing images of the bright, fractured region known as the "wispy terrain." These features are tectonic ridges and faults formed by geologic activity on the moon sometime in the past. Scientists will now be able to measure the depth and extent of them more accurately.


The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's 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.

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Cassini Takes Close-Up of Enceladus Northern Hemisphere

NASA's Cassini spacecraft will be making its close flyby of the northern hemisphere of Saturn's moon Enceladus today, Monday, Dec. 20. The closest approach will take place at 5:08 PM PST (8:08 EST) on Dec. 20, or 1:08 AM UTC on Dec. 21. The spacecraft will zip by at an altitude of about 48 kilometers (30 miles) above the icy moon's surface.

Cassini's fields and particles instruments will get priority during this flyby. They will be trying to characterize the particles that may form a tenuous atmosphere around Enceladus and see if they may be similar to the faint oxygen- and carbon-dioxide atmosphere detected recently around Rhea, another Saturnian moon. The instruments will be particularly interested in the Enceladus environment away from the jets emanating from the south polar region. A goal of the observations will be to try to measure the rate of dust coming off the moon from the bombardment of micrometeoroids alone. These measurements will help scientists understand the rate of micrometeoroid bombardment in the Saturn system, which will help them get at the age of Saturn's main rings.

The composite infrared spectrometer and imaging cameras will also be active, looking for additional hot spots on the moon and taking pictures of some regions at a higher resolution than is currently available.

This is the 13th flyby of Enceladus in Cassini's mission and takes a similar path to the last Enceladus flyby.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif. manages the mission for NASA's Science Mission Directorate, Washington, D.C.

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NASA Scientists Theorize Final Growth Spurt for Planets

A team of NASA-funded researchers has unveiled a new theory that contends planets gained the final portions of their mass from a limited number of large comet or asteroid impacts more than 4.5 billion years ago. These impacts added less than one percent of the planets' mass.

Scientists hope the research not only will provide a better historical picture of the birth and evolution of Earth, the moon and Mars, but also allow researchers to better explore what happened in our solar system's beginning and middle stages of planet formation.

“No one has a model of precisely what happened at the end of planet formation—we’ve had a broad idea—but variables such as impactor size, the approximate timing of the impacts, and how they affect the evolution of the planets are unknown,” said William Bottke, principal investigator from the Southwest Research Institute (SWRI) in Boulder, Colo. “This research hopefully provides better insights into the early stages of planet formation.”

The team used numerical models, lunar samples returned by Apollo astronauts and meteorites believed to be from Mars to develop its findings. The scientists examined the abundances of elements such as gold and platinum in the mantles, or layers beneath the crust, of Earth, the moon and Mars. Consistent with previous studies, they concluded the elements were added by a process called late accretion during a planet's final growth spurt.

"These impactors probably represent the largest objects to hit Earth since the giant impact that formed our moon," Bottke said. “They also may be responsible for the accessible abundance of gold, platinum, palladium, and other important metals used by our society today in items ranging from jewelry to our cars’ catalytic convertors.”

The results indicate the largest Earth impactor was between 1,500 - 2,000 miles in diameter, roughly the size of Pluto. Because it is smaller than Earth, the moon avoided such enormous projectiles and was only hit by impactors 150 - 200 miles wide. These impacts may have played important roles in the evolution of both worlds. For example, the projectiles that struck Earth may have modified the orientation of its spin axis by 10 degrees, while those that hit the moon may have delivered water to its mantle.

"Keep in mind that while the idea the Earth-moon system owes its existence to a single, random event was initially viewed as radical, it is now believed that large impacts were commonplace during the final stages of planet formation,’ Bottke said. “Our new results provide additional evidence that the effects of large impacts did not end with the moon-forming event."

The paper, "Stochastic Late Accretion to the Earth, Moon, and Mars," was published in the Dec. 9 issue of Science. It was written by Bottke and David Nesvorny of SWRI; Richard J. Walker of the University of Maryland; James Day of the University of Maryland and Scripps Institution of Oceanography, University of California, San Diego; and Linda Elkins-Tanton of the Massachusetts Institute of Technology. The research is funded by the NASA Lunar Science Institute (NLSI) at the agency's Ames Research Center in Moffett Field, Calif.

The NLSI is a virtual organization that enables collaborative, interdisciplinary research in support of NASA lunar science programs. The institute uses technology to bring scientists together around the world and comprises competitively selected U.S. teams and several international partners. NASA's Science Mission Directorate and the Exploration Systems Mission Directorate at the agency's Headquarters in Washington, funds the institute, which is managed by a central office at Ames.

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WISE Sees an Explosion of Infrared Light

A circular rainbow appears like a halo around an exploded star in this new view of the IC 443 nebula from NASA's Wide-field Infrared Survey Explorer, or WISE.

When massive stars die, they explode in tremendous blasts, called supernovae, which send out shock waves. The shock waves sweep up and heat surrounding gas and dust, creating supernova remnants like the one pictured here. The supernova in IC 443 happened somewhere between 5,000 and 10,000 years ago.

In this WISE image, infrared light has been color-coded to reveal what our eyes cannot see. The colors differ primarily because materials surrounding the supernova remnant vary in density. When the shock waves hit these materials, different gases were triggered to release a mix of infrared wavelengths.

The supernova remnant's northeastern shell, seen here as the violet-colored semi-circle at top left, is composed of sheet-like filaments that are emitting light from iron, neon, silicon and oxygen gas atoms and dust particles heated by a fast shock wave traveling at about 100 kilometers per second, or 223,700 mph.

The smaller southern shell, seen in bright bluish colors, is constructed of clumps and knots primarily emitting light from hydrogen gas and dust heated by a slower shock wave traveling at about 30 kilometers per second, or 67,100 miles per hour. In the case of the southern shell, the shock wave is interacting with a nearby dense cloud. This cloud can be seen in the image as the greenish dust cutting across IC 443 from the northwest to southeast.

IC 443 can be found near the star Eta Geminorum, which lies near Castor, one of the twins in the constellation Gemini.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The 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. More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu and http://www.jpl.nasa.gov/wise .

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Pits, Flows, Other Scenes in New Set of Mars Images

Newly released images from 340 recent observations of Mars by the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter show details of a wide assortment of Martian environments.

Strewn boulders and rippled sand lie on the floors of two shadowy, steep-walled pits. Mounds in another region appear to be mud volcanoes, which may have brought fine-grained material to the surface from deep underground. In the Tharsis volcanic region, the intersection of a lava flow with a trough caused by ground collapse allows seeing whether the flow happened before or after the collapse.

These and thousands of other images from HiRISE observations between Oct. 1 and Nov. 1, 2010, are now available on NASA's Planetary Data System (http://pds.jpl.nasa.gov/) and the camera team's website (http://hirise.lpl.arizona.edu).

The camera is one of six instruments on NASA's Mars Reconnaissance Orbiter, which reached Mars in 2006. It has made more than 17,000 observations. Each observation covers an area of several square miles on Mars and reveals details as small as desks.

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NASA Aids in Characterizing Super-Earth Atmosphere

PASADENA, Calif. -- A team of astronomers, including two NASA Sagan Fellows, has made the first characterizations of a super-Earth's atmosphere, by using a ground-based telescope. A super-Earth is a planet up to three times the size of Earth and weighing up to 10 times as much. The findings, reported in the Dec. 2 issue of the journal Nature, are a significant milestone toward eventually being able to probe the atmospheres of Earth-like planets for signs of life.

The team determined the planet, GJ 1214b, is either blanketed with a thin layer of water steam or surrounded by a thick layer of high clouds. If the former, the planet itself would have an icy composition. If the latter, the planet would be rocky or similar to the composition of Neptune, though much smaller.

"This is the first super-Earth known to have an atmosphere," said Jacob Bean, a NASA Sagan Fellow and astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "But even with these new measurements, we can't say yet what that atmosphere is made of. This world is being very shy and veiling its true nature from us."

GJ 1214b, first discovered in December 2009, is 2.7 times the size of Earth and 6.5 times as massive. Previous observations of the planet's size and mass demonstrated it has a low density for its size, leading astronomers to conclude the planet is some kind of solid body with an atmosphere.

The planet orbits close to its dim star, at a distance of 0.014 astronomical units. An astronomical unit is the distance between Earth and the sun, approximately 93 million miles. GJ 1214b circles too close to its star to be habitable by any life forms.

Bean and his team observed infrared light as the planet crossed in front of its star. During such transits, the star's light filters through the atmosphere. Gases absorb the starlight at particular wavelengths, leaving behind chemical fingerprints detectable from Earth. This same type of technique has been used to study the atmospheres of distant "hot Jupiters," or Jupiter-like planets orbiting close to their stars, and found gases like hydrogen, methane and sodium vapor.

In the case of the super-Earth, no chemical fingerprints were detected; however, this doesn't mean there are no chemicals present. Instead, this information ruled out some possibilities for GJ 1214b's atmosphere, and narrowed the scope to either an atmosphere of water steam or high clouds. Astronomers believe it's more likely the atmosphere is too thin around the planet to let enough light filter through and reveal chemical fingerprints.

"A steamy atmosphere would have to be very dense – about one-fifth water vapor by volume -- compared to our Earth, with an atmosphere that's four-fifths nitrogen and one-fifth oxygen with only a touch of water vapor," Bean said. "During the next year, we should have some solid answers about what this planet is truly like."

The team, which included Bean's co-authors -- Eliza Miller-Ricci Kempton, a NASA Sagan Fellow at the University of California in Santa Cruz, and Derek Homeier of the Institute for Astrophysics in Gottingen, Germany -- examined GJ 1214b using the ground-based Very Large Telescope at Paranal Observatory in Chile.

"This is an important step forward, narrowing our understanding of the atmosphere of this planet," said NASA Exoplanet Exploration Program Scientist Douglas Hudgins at NASA Headquarters in Washington. "Bizarre worlds like this make exoplanet science one of the most compelling areas in astrophysics today."

The Sagan Fellowship Program is administered by the NASA Exoplanet Science Institute at the California Institute of Technology in Pasadena. Its purpose is to advance the scientific and technical goals of NASA's Exoplanet Exploration Program. The program is managed for NASA by the Jet Propulsion Laboratory in Pasadena, Calif. Caltech manages JPL for NASA.

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So you Think you can Solve a Cosmology Puzzle?

Cosmologists have come up with a new way to solve their problems. They are inviting scientists, including those from totally unrelated fields, to participate in a grand competition. The idea is to spur outside interest in one of cosmology's trickiest problems -- measuring the invisible dark matter and dark energy that permeate our universe.

The results will help in the development of new space missions, designed to answer fundamental questions about the history and fate of our universe.

"We're hoping to get more computer scientists interested in our work," said cosmologist Jason Rhodes of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who is helping to organize the challenge, which begins on Dec. 3, 2010. "Some of the mathematical problems in our field are the same as those in machine-learning applications -- for example facial-recognition software."

JPL and several European Universities, including The University of Edinburgh and University College London in the United Kingdom, are helping to support the event, which is funded by a European Union group called Pattern Analysis, Statistical Modelling and Computation Learning. The principal investigator is Thomas Kitching of the University of Edinburgh.

This year, the competition, which has operated since 2008, is called GREAT 2010, after GRavitational lEnsing Accuracy Testing. The challenge is to solve a series of puzzles involving distorted images of galaxies. Occasionally in nature, a galaxy is situated behind a clump of matter that is causing the light from the galaxy to bend. The result is a magnified and skewed image of the galaxy. In the most extreme cases, the warping results in multiple images and even a perfect ring, called an Einstein Ring after Albert Einstein, who predicted the effect. But most of the time, the results are more subtle and a galaxy image is distorted just a tiny bit -- not even enough to be perceived by eye. This is called weak gravitational lensing, or just weak lensing for short.

Weak lensing is a powerful tool for unlocking the fabric of our universe. Only four percent of our universe consists of the stuff that makes up people, stars and anything with atoms. Twenty-four percent is dark matter -- a mysterious substance that we can't see but which tugs on the regular matter we can see. Most of our universe, 72 percent, consists of dark energy, which is even more baffling than dark matter. Dark energy is gravity's nemesis -- where gravity pulls, dark energy pushes. By studying lensed, or distorted, galaxies, scientists can create better maps of dark matter -- and by studying how dark matter changes over time, they can better understand dark energy.

Weak lensing is a promising method for tackling these questions. The 2010 U.S. National Research Council Decadal Survey on astronomy and astrophysics has ranked mission proposals using this method as high priorities.

The GREAT 2010 challenge is designed to improve weak-lensing know-how. Participants will start with fuzzy pictures of galaxies that have been distorted ever so slightly by invisible dark matter parked in front of them. The effect is so small that you can't see it with your eyes. The problem is even trickier because the telescopes are also distorting the galaxy images to an even greater degree than the dark matter. It takes complex techniques -- mathematical models and image-analysis algorithms -- to tease apart these various influences and ultimately discover how dark matter is warping a galaxy's shape.

"This is an image-analysis challenge. You don't need to be an astronomer or cosmologist to help measure the weak-lensing effect," said Kitching. "This challenge is meant to encourage a multidisciplinary approach to the problem."

Participants will have nine months to solve a series of thousands of puzzles. The winners will be announced at a closing ceremony and workshop held at JPL. Prize-winners can expect some kind of cool gadget -- as well as the satisfaction of having brought the world one step closer to understanding what makes our universe tick.

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LRO Supports Historic Lunar Impact Mission

The lunar rocks brought back to the Earth by the Apollo astronauts were found to have very little water, and to be much drier than rocks on Earth. An explanation for this was that the Moon formed billions of years ago in the solar system's turbulent youth, when a Mars-sized planet crashed into Earth. The impact stripped away our planet's outer layer, sending it into orbit. The pieces later coalesced under their own gravity to form our Moon. Heat from all this mayhem vaporized most of the water in the lunar material, so the water was lost to space.

However, there was still a chance that water might be found in special places on the Moon. Due to the Moon's orientation to the Sun, scientists theorized that deep craters at the lunar poles would be in permanent shadow and thus extremely cold and able to trap volatile material like water as ice perhaps delivered there by comet impacts or chemical reactions with hydrogen carried by the solar wind.

Last year on October 9, NASA's LCROSS (Lunar Crater Remote Observation and Sensing Satellite) intentionally crashed its companion Centaur upper stage into the Cabeus crater near the lunar south pole. The idea was to kick up debris from the bottom of the crater so its composition could be analyzed. The Centaur hit at over 5,600 miles per hour, sending up a plume of material over 12 miles high.

"Seeing mostly pure water ice grains in the plume means water ice was somehow delivered or chemical processes are causing ice to accumulate in large quantities," said Anthony Colaprete, LCROSS project scientist and principal investigator at NASA's Ames Research Center, Moffett Field, Calif. "Furthermore, the diversity and abundance of certain materials called volatiles in the plume, suggest a variety of sources, like comets and asteroids, and an active water cycle within the lunar shadows."

Artist's concept of the LCROSS spacecraft This is an artist's rendering of the LCROSS spacecraft (foreground) and Centaur separation. Credit: NASA
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Artist concept of LRO This is an artist's rendering of the Lunar Reconnaissance Orbiter spacecraft. Credit: NASA
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LCROSS LRO Diviner Lunar Radiometer Experiment surface temperature map of the south polar region of the moon. The map shows the locations of several intensely cold impact craters that are potential cold traps for water ice as well as a range of other icy compounds commonly observed in comets. The LCROSS spacecraft was targeted to impact one of the coldest of these craters, and many of these compounds were observed in the ejecta plume. Credit: UCLA/NASA/Jet Propulsion Laboratory, Pasadena, Calif./Goddard
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LCROSS Diviner brightness temperature swath acquired about 90 seconds after the LCROSS impact, the location of which is indicated by the white arrow. Based on the Diviner measurements, the impact site was heated to more than 380°C (1,300°F). Credit: UCLA/NASA/JPL/Goddard
› Larger image LCROSS was a companion mission to NASA's Lunar Reconnaissance Orbiter (LRO) mission.

The two missions were designed to work together, and support from LRO was critical to the success of LCROSS. During impact, LRO, which is normally looking at the lunar surface, was tilted toward the horizon so it could observe the plume. Shortly after the Centaur hit the Moon, LRO flew past debris and gas from the impact while its instruments collected data.

"LRO assisted LCROSS in two primary ways -- selecting the impact site and confirming the LCROSS observations," said Gordon Chin of NASA's Goddard Space Flight Center, Greenbelt, Md., LRO associate project scientist.

"Since observatories on Earth were also planning to view the impact, there were a lot of constraints on the location -- the impact plume had to rise out of the crater and into sunlight, and it had to be visible from Earth," said Chin.

Prior to the impact, LRO's instruments worked together to map and provide details on the polar regions, according to Chin. For example, LRO's Lunar Orbiter Laser Altimeter (LOLA) instrument built up three-dimensional (topographic) maps of the surface. This data was plugged into computer simulations to see how shadows change as the Moon moves in its orbit, so that regions in permanent shadow could be identified. The Lunar Reconnaissance Orbiter Camera (LROC) helped by making images of the actual regions of light and shade, which were used to verify the simulation's accuracy. Finally, LOLA measured the depths of polar craters to find areas where the impact could still be seen from Earth.

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Cassini Back to Normal, Ready for Enceladus

NASA's Cassini spacecraft resumed normal operations today, Nov. 24. All science instruments have been turned back on, the spacecraft is properly configured and Cassini is in good health. Mission managers expect to get a full stream of data during next week's flyby of the Saturnian moon Enceladus.

Cassini went into safe mode on Nov. 2, when one bit flipped in the onboard command and data subsystem computer. The bit flip prevented the computer from registering an important instruction, and the spacecraft, as programmed, went into the standby mode. Engineers have traced the steps taken by the computer during that time and have determined that all spacecraft responses were proper, but still do not know why the bit flipped.

The flyby on Nov. 30 will bring Cassini to within about 48 kilometers (30 miles) of the surface of Enceladus. At 61 degrees north latitude, this encounter and its twin three weeks later at the same altitude and latitude, are the closest Cassini will come to the northern hemisphere surface of Enceladus during the extended Solstice mission. (Cassini's closest-ever approach to the surface occurred in October 2008, when it dipped to an altitude of 25 kilometers, or 16 miles.)

During the closest part of the Nov. 30 flyby, Cassini's radio science subsystem will make gravity measurements. The results will be compared with those from an earlier flyby of the Enceladus south pole to understand the moon's interior structure better. Cassini's fields and particles instruments will sample the charged particle environment around Enceladus. Other instruments will capture images in visible light and other parts of the light spectrum after Cassini makes its closest approach.

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.

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Pits, Flows, Other Scenes in New Set of Mars Images

Newly released images from 340 recent observations of Mars by the High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter show details of a wide assortment of Martian environments.

Strewn boulders and rippled sand lie on the floors of two shadowy, steep-walled pits. Mounds in another region appear to be mud volcanoes, which may have brought fine-grained material to the surface from deep underground. In the Tharsis volcanic region, the intersection of a lava flow with a trough caused by ground collapse allows seeing whether the flow happened before or after the collapse.

These and thousands of other images from HiRISE observations between Oct. 1 and Nov. 1, 2010, are now available on NASA's Planetary Data System (http://pds.jpl.nasa.gov/) and the camera team's website (http://hirise.lpl.arizona.edu).

The camera is one of six instruments on NASA's Mars Reconnaissance Orbiter, which reached Mars in 2006. It has made more than 17,000 observations. Each observation covers an area of several square miles on Mars and reveals details as small as desks.

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Solar Observation Mission Celebrates 15 Years

On December 2, 1995, the Solar and Heliospheric Observatory or SOHO was launched into space from Cape Canaveral aboard an Atlas IIAS rocket. The joint ESA/NASA project began its work observing the sun at a time when the term "solar weather" was almost never used.

Fifteen years later, SOHO has revolutionized what we know about the solar atmosphere and violent solar storms produced by the sun. SOHO has become an expert comet-hunter, nightly news leader and a workhorse that helped create the field of near-real-time space weather reporting as we know it –- but it started as a tool to answer three scientific questions about the sun.

"We were looking for answers to three long-standing problems in solar physics," said Joe Gurman, “the solar neutrino problem, the coronal heating mystery, and the question of what causes solar wind acceleration." Gurman works at NASA's Goddard Space Flight Center in Greenbelt, Md., and has been the U.S. project scientist for SOHO since 1998.

Placed into orbit around the L1 Lagrangian point between Earth and the sun, SOHO was able to observe the sun continuously without Earth ever obstructing its view. With its uninterrupted observations, says Gurman, SOHO has significantly helped with all three original questions.

First, the so-called solar neutrino problem was a conflict between how many neutrinos were predicted by fusion and models of the solar interior versus how many were in fact detected. SOHO confirmed that the interior models were correct and helped show that, instead, the detectors were not finding all the neutrinos since they were changing after they left the sun. Second is the coronal heating mystery, so called because the Sun's outermost atmosphere, or corona, is unexpectedly hundreds of times hotter than the sun's surface. SOHO helped determine that the movement of the Sun’s small-scale magnetic fields themselves could contribute, in principle, sufficient energy to heat the corona. Third, SOHO observed that the acceleration of the solar wind appears to be powered by a special kind of waves that can accelerate certain particles preferentially.

SOHO is perhaps best known for its observations of coronal mass ejections, or CMEs. These blasts of gas and magnetic fields are a fundamental concern for those who track and attempt to forecast space weather. But when SOHO launched in 1995, there was disagreement over what a CME headed for earth looked like. The first ever videos of a CME wave in the lower corona in April of 1997, combined with SOHO’s white light coronagraph observations of the accompanying “halo” CME, changed all that.

Steele Hill, who leads public outreach for SOHO at Goddard, had then only been working for the SOHO team for six months. "It was the first time we had witnessed an event like that. We could track it, predict its direction, and say that in two to three days it will have some impact on Earth.” Hill pulled together some SOHO files and made a movie. . . and it was the first story on the national news that night in April 1997.

After a good 15-years, SOHO isn't easing in to retirement yet. A long archive of data such as SOHO's is necessary to spot some of the tiniest waves that propagate through the body of the sun. Known as buoyancy or gravity-mode waves, these waves only disturb the surface of the sun at a speed of a millimeter per second.

"That's a pretty hard measurement to do," says Gurman. "With 15 years of observations, we just might have a strong enough signal."

In addition, SOHO is still our only solar observatory to have gathered images of the sun during a solar maximum. The last maximum was in 2000. As we move into the next peak in 2013, it will be SOHO's legacy that allows scientists to compare and contrast what we see now in newer missions such as the Solar Dynamics Observatory (SDO) and the Solar TErrestrial RElations Observatory (STEREO) to what was seen then.

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