Showing posts with label nasa images. Show all posts
Showing posts with label nasa images. Show all posts

Tuesday, July 22, 2014

NASA Cassini Spacecraft Provides New View of Saturn and Earth

NASA Cassini Spacecraft Provides New View of Saturn and Earth:

The Day the Earth Smiled
On July 19, 2013, in an event celebrated the world over, NASA's Cassini spacecraft slipped into Saturn's shadow and turned to image the planet, seven of its moons, its inner rings -- and, in the background, our home planet, Earth. Image credit: NASA/JPL-Caltech/SSI
› Full image and caption

November 12, 2013

• Natural-color portrait that is first to show Saturn, its moons and rings, plus Earth, Venus and Mars


• Sweeps nearly 405,000 miles across Saturn and its inner rings


NASA has released a natural-color image of Saturn from space, the first in which Saturn, its moons and rings, and Earth, Venus and Mars, all are visible.


The new panoramic mosaic of the majestic Saturn system taken by NASA's Cassini spacecraft, which shows the view as it would be seen by human eyes, was unveiled at the Newseum in Washington on Tuesday.


Cassini's imaging team processed 141 wide-angle images to create the panorama. The image sweeps 404,880 miles (651,591 kilometers) across Saturn and its inner ring system, including all of Saturn's rings out to the E ring, which is Saturn's second outermost ring. For perspective, the distance between Earth and our moon would fit comfortably inside the span of the E ring.


"In this one magnificent view, Cassini has delivered to us a universe of marvels," said Carolyn Porco, Cassini's imaging team lead at the Space Science Institute in Boulder, Colo. "And it did so on a day people all over the world, in unison, smiled in celebration at the sheer joy of being alive on a pale blue dot."


The mosaic is part of Cassini's "Wave at Saturn" campaign, where on July 19, people for the first time had advance notice a spacecraft was taking their picture from planetary distances. NASA invited the public to celebrate by finding Saturn in their part of the sky, waving at the ringed planet and sharing pictures over the Internet.


An annotated version of the Saturn system mosaic labels points of interest. Earth is a bright blue dot to the lower right of Saturn. Venus is a bright dot to Saturn's upper left. Mars also appears, as a faint red dot, above and to the left of Venus. Seven Saturnian moons are visible, including Enceladus on the left side of the image. Zooming into the image reveals the moon and the icy plume emanating from its south pole, supplying fine, powder-sized icy particles that make up the E ring.


The E ring shines like a halo around Saturn and the inner rings. Because it is so tenuous, it is best seen with light shining from behind it, when the tiny particles are outlined with light because of the phenomenon of diffraction. Scientists who focus on Saturn's rings look for patterns in optical bonanzas like these. They use computers to increase dramatically the contrast of the images and change the color balance, for example, to see evidence for material tracing out the full orbits of the tiny moons Anthe and Methone for the first time.


"This mosaic provides a remarkable amount of high-quality data on Saturn's diffuse rings, revealing all sorts of intriguing structures we are currently trying to understand," said Matt Hedman, a Cassini participating scientist at the University of Idaho in Moscow. "The E ring in particular shows patterns that likely reflect disturbances from such diverse sources as sunlight and Enceladus' gravity."


Cassini does not attempt many images of Earth because the sun is so close to our planet that an unobstructed view would damage the spacecraft's sensitive detectors. Cassini team members looked for an opportunity when the sun would slip behind Saturn from Cassini's point of view. A good opportunity came on July 19, when Cassini was able to capture a picture of Earth and its moon, and this multi-image, backlit panorama of the Saturn system.


"With a long, intricate dance around the Saturn system, Cassini aims to study the Saturn system from as many angles as possible," said Linda Spilker, Cassini project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Beyond showing us the beauty of the Ringed Planet, data like these also improve our understanding of the history of the faint rings around Saturn and the way disks around planets form -- clues to how our own solar system formed around the sun."


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 many more images of Saturn, its rings and moons, as well as other scientific data.


The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team is based at the Space Science Institute, Boulder, Colo.


To view the image, visit: http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA17172 .


A new version of the collage of photos shared by the public, with the Saturn system as backdrop, is available at: http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA17679 .


More information about Cassini is available at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


Dwayne Brown 202-358-1726

NASA Headquarters, Washington

dwayne.c.brown@nasa.gov


Steve Mullins 720-974-5859

Space Science Institute, Boulder, Colo.

media@ciclops.org


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Curiosity Out of Safe Mode

Curiosity Out of Safe Mode:

Mars Rover Curiosity in Artist's Concept, Close-up
This artist concept features NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or present ability to sustain microbial life. Image credit:
NASA/JPL-Caltech
› Full image and caption

November 12, 2013

Mars Science Laboratory Mission Status Report


NASA's Mars Science Laboratory Project received confirmation from Mars Sunday (Nov. 10) that the Curiosity rover has successfully transitioned back into nominal surface operations mode. Curiosity had been in safe mode since Nov. 7, when an unexpected software reboot (also known as a warm reset) occurred during a communications pass with the Mars Reconnaissance Orbiter. Mission science planning will resume tomorrow, and Curiosity science operations will recommence on Thursday.


"We returned to normal engineering operations," said Rajeev Joshi, a software and systems engineer for the Curiosity mission at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We are well into planning the next several days of surface operations and expect to resume our drive to Mount Sharp this week."


After analyzing the data returned by the spacecraft on Thursday evening, Nov. 7 (Pacific Time), the Curiosity operations team was able to determine the root cause. An error in existing onboard software resulted in an error in a catalog file. This caused an unexpected reset when the catalog was processed by a new version of flight software which had been installed on Thursday. The team was able to replicate the problem on ground testbeds the following day. Commands recovering the spacecraft were uplinked to the spacecraft early Sunday morning.


NASA's Mars Science Laboratory Project is using Curiosity to assess whether areas inside Gale Crater ever offered a habitable environment for microbes. JPL, a division of the California Institute of Technology in Pasadena, manages the project for NASA's Science Mission Directorate in Washington.


More information about Curiosity is online at http://www.jpl.nasa.gov/msl , http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at: http://www.facebook.com/marscuriosity and on Twitter at: http://www.twitter.com/marscuriosity .

DC Agle 818-393-9011

Jet Propulsion Laboratory, Pasadena, Calif.

agle@jpl.nasa.gov


2013-330
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NASA Helps Melt Secrets of Great Lakes Ice

NASA Helps Melt Secrets of Great Lakes Ice:

colorful radar photo of Lake Superior
A color-coded image of major ice types on Lake Superior, made from a RADARSAT1 radar backscatter image using a new NASA and NOAA-developed technique. Credit: NOAA Great Lakes Environmental Research Laboratory and NASA/JPL-Caltech

› Larger image

November 13, 2013

Two scientists from NASA and NOAA have developed a new space-based technique for monitoring the ice cover of the Great Lakes that is so accurate it can identify a narrow channel of open water cut through the ice by an icebreaker -- even at night.


"In the dark, it's difficult to read a map that's right in front of you," said Son Nghiem of NASA's Jet Propulsion Laboratory, Pasadena, Calif., one of the developers of the new technique. "Yet we now have a way to use satellite radars almost 500 miles [800 kilometers] out in space to see through clouds and darkness and map ice across the Great Lakes."


Ice on the Great Lakes puts a big chill on the U.S. and Canadian economies, affecting shipping, fishing and also public safety when winter and spring flooding are caused by ice jams. It has a significant impact on the regional environment and ecological systems as well. Yet previous techniques of analyzing satellite observations of the ice sometimes misidentified ice as water and vice versa.


The new method, co-developed by Nghiem and his colleague George Leshkevich of NOAA's Great Lakes Environmental Research Laboratory, Ann Arbor, Mich., not only corrects that problem, it also gives a more accurate analysis of ice characteristics, such as whether the ice is dense or full of bubbles, and whether it has melted and refrozen.


The method uses a special dictionary that translates binary digital data from satellite radar instruments on the Canadian Space Agency's RADARSAT-1/2, the European Space Agency's European Remote Sensing Satellite 2 (ERS-2), and Envisat to identify and map different types of ice over the Great Lakes. The researchers compiled the dictionary by pairing each observed ice type to a library of unique radar signatures that were measured on the lakes using a JPL-developed advanced radar aboard a U.S. Coast Guard icebreaking ship.


Leshkevich said the method has now been transitioned to NOAA for routine use in generating ice maps across the Great Lakes. "These maps will provide important information for environmental management, ice forecasting and modeling, off-shore wind farm development, operational icebreaking activities in support of winter navigation, and science research."


The more accurate classification of ice will also be useful for scientific research into such questions as how the Great Lakes are responding to, and leading, climate change in the upper Midwest.


Results of the study were published recently in the Journal of Great Lakes Research.


For more information, visit: http://www.iaglr.org/jglr/release/39/2013.05.003_leshkevich.php .

Written by Carol Rasmussen


Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena, Calif.

alan.buis@jpl.nasa.gov


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Monday, July 21, 2014

Nature Pulls a Fast One on Astronomers

Nature Pulls a Fast One on Astronomers:

Two Galaxies Masquerading as One
The edge-on spiral galaxy UGC 10288 appeared to be a single object in previous observations. However, new detailed radio data from the NRAO's Jansky Very Large Array (VLA) revealed that the large perpendicular extension of UGC 10288's halo (blue) is really a distant background galaxy with radio jets. Image credit: VLA/NASA/JPL-Caltech/SDSS/NOAO/University of Manitoba
› Full image and caption


November 14, 2013

What might look like a colossal jet shooting away from a galaxy turns out to be an illusion. New data from the National Science Foundation's Karl G. Jansky Very Large Array (VLA) reveal that two galaxies, one lying behind the other, have been masquerading as one.


In a new image highlighting the chance alignment, radio data from the VLA are blue and infrared observations from NASA's Spitzer Space Telescope and Wide-field Infrared Survey Explorer (WISE) are yellow and orange, respectively. Visible data are also shown, with starlight in purplish blue and heated gas in rose.


The closer galaxy, called UGC 10288, is located 100 million light-years away. It is spiral in shape, but from our viewpoint on Earth, we are seeing its thin edge. The farther galaxy, seen in blue, is nearly 7 billion light-years away. Two giant jets shoot away from this galaxy, one of which is seen above the plane of the closer galaxy's disk.


Earlier radio images of the two galaxies appeared as one fuzzy blob, and fooled astronomers into thinking they were looking at one galaxy. Thanks to the VLA pulling the curtain back on the disguised duo, the scientists have a unique opportunity to learn otherwise-unobtainable facts about the nearer galaxy.


"We can use the radio waves from the background galaxy, coming through the nearer one, as a way to measure the properties of the nearer galaxy," said Judith Irwin, of Queen's University, Canada, lead author of a recent paper on the findings, appearing online Nov. 15 in the Astronomical Journal.


Observations from Spitzer and WISE helped to reveal new structures above and below the plane of the closer galaxy's disk. For example, Spitzer helped confirm an arc-like feature rising more than 11,000 light-years above the disk, which was seen in the radio observations.


Irwin worked with an international team of astronomers from North America, India and Europe who are part of the "Continuum Halos in Nearby Galaxies -- an EVLA Survey" (CHANG-ES) consortium.


The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.


NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .


JPL manages and operates the WISE mission for NASA's Science Mission Directorate. The WISE mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at Caltech. 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 .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


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NASA Damage Map Helps in Typhoon Disaster Response

NASA Damage Map Helps in Typhoon Disaster Response:

NASA-Generated Damage Map To Assist With Typhoon Haiyan Disaster Response
When Super Typhoon Haiyan, one of the most powerful storms ever recorded on Earth, struck the Philippines Nov. 8, 2013, it tore a wide swath of destruction across large parts of the island nation. Image Credit:
ASI/NASA/JPL-Caltech
› Full image and caption


November 13, 2013

A new, space-based map generated by scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., in collaboration with the Italian Space Agency to assist in disaster response efforts shows the regions in the Philippines hit hardest by Super Typhoon Haiyan. The typhoon tore a wide swath of devastation across the island nation on Nov. 8, 2013.


The map, which depicts the storm's destruction, is available online at:
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA17687 .


This 27-by-33-mile (43-by-53-kilometer) map covers a region near Tacloban City, where the massive storm, one of the most powerful ever recorded on Earth, made landfall. It was made from radar imagery obtained before and after the typhoon hit. It was processed by JPL's Advanced Rapid Imaging and Analysis (ARIA) team using X-band interferometric synthetic aperture radar data from the Italian Space Agency's COSMO-SkyMed satellite constellation. The technique uses a prototype algorithm to rapidly detect surface changes caused by natural or human-produced damage.


The technique is most sensitive to detecting destruction of the human-made environment. In the image, damage detected by radar is shown as an overlay on a Google Earth image. Areas in red reflect the heaviest damage to cities and towns in the storm's path. The estimated intensity of damage is proportional to the opacity of the red. When the radar observes areas that have little to no destruction, its image pixels are transparent. The satellite data used to generate the map span the time frame from Aug. 19 to Nov. 11, 2013. Each pixel in the damage map measures approximately 33 yards (30 meters) across.


ARIA is a JPL- and NASA-funded project being developed by JPL and the California Institute of Technology, Pasadena, Calif. It is building an automated system for providing rapid and reliable GPS and satellite data to support the local, national and international hazard monitoring and response communities. Using space-based imagery of disasters, ARIA data products can provide rapid assessments of the geographic region affected by a disaster, as well as detailed imaging of the locations where damage occurred.


NASA is making the data publicly available for agencies that might be responding to the event through the U.S. Geological Survey's Earth Resources Observation and Science (EROS) Data Center's Hazards Data Distribution System, as well as through NASA's ARIA website.


The ARIA team began developing and evaluating this technique using case studies from the magnitude 6.3 earthquake in Christchurch, New Zealand, in February 2011 to detect building damage, landslides and liquefaction. Following the magnitude 9.0 earthquake in Tohoku, Japan, in March 2011, the team used the technique to assess tsunami damage, as well as ground deformation from high-rate GPS network and imaging radar satellites. Those ground-deformation data were downloaded more than 1,400 times within the first two days they were available. Following last year's Hurricane Sandy, the team produced damage maps that were delivered to the International Charter 11 days after landfall and subsequently validated with crowdsourcing with the assistance of the GISCorps.


The ARIA team continues to improve its response time for generating products -- the Haiyan satellite data were available three days after landfall and were processed within 11 hours of data acquisition. The improved response time has been aided by NASA's recent joint collaboration with the Italian Space Agency, which operates four identical radar satellites.


For more information about ARIA, visit: http://aria.jpl.nasa.gov .


Caltech manages JPL for NASA.

Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena, Calif.

Alan.buis@jpl.nasa.gov


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WISE Catalog Just Got Wiser

WISE Catalog Just Got Wiser:

AllWISE Brings Galaxies Out of Hiding
The new AllWISE catalog will bring distant galaxies that were once invisible out of hiding, as illustrated in this image.
› Full image and caption


November 14, 2013

NASA's WISE mission has released a new and improved atlas and catalog brimming with data on three-quarters of a billion objects detected during two full scans of the sky.


WISE, which stands for Wide-field Infrared Survey Explorer, scanned the entire sky in infrared light in 2010, snapping a dozen pictures of every star and galaxy. By October of that year, the spacecraft ran out of the coolant needed to chill some of its heat-seeking detectors. NASA then decided to fund a second scan of the sky to look for asteroids and comets, in a project called NEOWISE.


But the images from that second sky scan were designed to catch moving asteroids, not stars and galaxies. Now NASA has funded a project called AllWISE to stack up all the WISE images, including those from the second sky scan, thereby doubling exposure times and making new stars and galaxies visible.


"By stacking up the data, we have created a monster database with dozens of individual measurements on every one of the infrared sources we detect," said Ned Wright of UCLA, the principal investigator of WISE.


One new feature of the enhanced WISE images is the ability to search for nearby stars, especially cooler ones that only show up in infrared light. Objects that are closer to us will appear to move across the sky over time in relation to background stars. This is the same reason why the planets march across our night skies while the stars seem to stay still. With the new atlas, astronomers can look at images of the sky taken six months apart; if something jumps across the images, then it must be located nearby and could be a never-before-seen neighbor.


The new catalog will also help with studies of distant galaxies, bringing those that were invisible to us before out of hiding.


"The extra depth of AllWISE lets us see galaxies so distant that their light was emitted in the first half of the history of the universe," said Peter Eisenhardt, the WISE project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.


In addition to AllWISE, NASA decided to wake up the WISE spacecraft again to search for more asteroids (see http://www.jpl.nasa.gov/news/news.php?release=2013-257 ).


The technical details for accessing the AllWISE data are online at: http://wise2.ipac.caltech.edu/docs/release/allwise/ .


NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages and operates the newly activated NEOWISE mission for NASA's Science Mission Directorate. The WISE mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in 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 .

Whitney Clavin (818) 354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-335
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Update on Near-Earth Objects

Update on Near-Earth Objects:

The orbits of 2013 UQ4, 2013 US10 and 2013 UP8 are shown as viewed from within the plane of the solar system
The orbits of 2013 UQ4, 2013 US10 and 2013 UP8 are shown as viewed from within the plane of the solar system (ecliptic plane), which makes clear their highly inclined orbits relative to Earth's orbit.
Image credit: NASA/JPL-Caltech
› Larger image

November 18, 2013

Near-Earth Object 2013 US10 is a Long-Period Comet

Updated November 6, 2013


While initial reports from the Minor Planet Center in Cambridge, Mass., categorized object 2013 US10 as a very large near-Earth asteroid, new observations now indicate that it is, in fact, a long-period comet, and it is now designated C/2013 US10 (Catalina). The comet was discovered by the Catalina Sky Survey near Tucson, Ariz., on Oct. 31, 2013, and linked to earlier pre-discovery Catalina observations made on Sept. 12. The initial orbit suggested this object is a large, short period, near-Earth asteroid, as reported here yesterday. An updated orbit, issued today by the Minor Planet Center, removed the September 12 observations that belong to another object and include earlier pre-discovery August and September observations made by the Catalina Sky Survey, the ISON-HD observatory in Russia and Hawaii's Pan-STARRS group. The new orbit indicates that this object is in a long-period, near parabolic orbit about the sun. Furthermore, observations made last night at the Canada-France-Hawaii telescope indicate the object is showing modest cometary activity, which means that yesterday's rough estimate for the object's size (about 12 miles, or 20 kilometers) must now be completely revised. A new size estimate is not yet available, but the object could very well be much smaller than yesterday's estimate.


_________________________________________________________________________


Surprising Recent Discoveries of Three Large Near-Earth Objects

November 5, 2013


Two surprisingly large Near-Earth Asteroids have been discovered in just the last week or so, as well as a third moderately large asteroid which, surprisingly, has also gone undetected until now, even though it can pass close enough to Earth to be classified as "potentially hazardous." Not since 1983 has any near-Earth asteroid been found as large as the approximately 12-mile (20-kilometer) size of the two new large ones. In fact, there are only three other known near-Earth asteroids that are of comparable size or larger than the two new large ones.


It is important to note that none of these three new large near-Earth asteroids can come close enough to Earth to represent a near-term threat to our planet.


The first of the new large near-Earth asteroid discoveries is named 2013 UQ4, and it is perhaps the most unusual. This approximately 12-mile (19-kilometer) wide object was spotted by the Catalina Sky Survey on Oct. 23 when the asteroid was 270 million miles (435 million kilometers) away from Earth. Not only is this object unusually large, it follows a very unusual, highly inclined, retrograde orbit about the sun, which means it travels around the sun in the opposite direction of all the planets and the vast majority of asteroids.


The only objects usually found in retrograde orbits are comets, which suggests that 2013 UQ4 may be the remains of an old comet that no longer possesses the near-surface ices required for it to become active while near the sun. Comets that have exhausted most, or all, of their volatile ices do not spew dust during sweeps through the inner-solar system like their less-seasoned, more hyperactive space kin. Without the telltale comet tails or atmospheres, dead comets look like, and in fact for all practical purposes are, asteroids.


As reported on Circular No. 9262 of the International Astronomical Union, the Massachusett's Institute of Technology's Richard Binzel, David Polishook and Rachel Bowens-Rubin observed this object on October 31 with NASA's 3-meter Infrared Telescope Facility in Hawaii and determined this object belongs to the so-called X-type spectral class and exhibits no obvious comet-like activity. This implies about a 4 percent reflectivity, from which they estimate a diameter of approximately 12 miles (19 kilometers).


The second very large near-Earth object, named 2013 US10, was discovered on October 31 by the Catalina Sky Survey. While the reflectivity of this object has not yet been determined, and hence its diameter is still uncertain, it is also likely to be about 12 miles (20 kilometers) in size. Only three near-Earth asteroids (1036 Ganymed, 433 Eros and 3552 Don Quixote) are of comparable size or larger.


Why has it taken so long to discover these large near-Earth asteroids? The delay in discovering 2013 UQ4 is more easily understood because it has a very long orbital period that has kept it out of Earth's neighborhood for centuries. But the delayed discovery of 2013 US10 is a bit harder to explain, since current population models suggest that almost all near-Earth asteroids of this size and orbit should have already been found. A contributing factor may be that this object's orbit does not allow it to get closer than 50 million miles (80 million kilometers) of Earth's orbit, so the asteroid seldom gets close enough to Earth to become easily detectable. However, NASA-supported telescopic surveys are now covering more sky and looking "deeper" than they ever have before, and in fact, 2013 US10 was first detected where it spends much of its time, well beyond the orbit of Jupiter.


The third of the recent discoveries is the approximately 1.2-kilometer (two-kilometer) near-Earth asteroid 2013 UP8, found on Oct. 25 by the Pan-STARRS group in Hawaii. This asteroid can approach quite close to Earth's orbit, within 3.4 million miles (5.5 million kilometers), which makes it a "potentially hazardous asteroid" (PHA). 2013 UP8 is in the top 5th percentile of the largest PHAs, most of which were found much earlier during NASA's asteroid survey program. Like the other new discoveries, this asteroid has gone undetected for a long time because it has not approached Earth closely for decades. But the increasingly capable NASA-supported asteroid surveys finally found this object while it was still at a large distance from Earth, well beyond the orbit of Mars.


NASA's Near-Earth Object Program at NASA Headquarters, Washington, manages and funds the search, study and monitoring of asteroids and comets whose orbits periodically bring them close to Earth. JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.


More information about asteroids and near-Earth objects is available at: http://neo.jpl.nasa.gov/ , http://www.jpl.nasa.gov/asteroidwatch and via Twitter at http://www.twitter.com/asteroidwatch .

DC Agle 818-393-9011

Jet Propulsion Laboratory, Pasadena, Calif.

agle@jpl.nasa.gov


2013-336
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Infant Galaxies Merge Near 'Cosmic Dawn'

Infant Galaxies Merge Near 'Cosmic Dawn':

Three-headed Galactic Blob
The big blob-like structure shown here, named Himiko after the legendary ancient queen of Japan, turns out to be three galaxies thought to be in the process of merging into one. In this image, infrared data from NASA's Spitzer Space Telescope are red; visible data from NASA's Hubble Space Telescope are green; and ultraviolet data from Japan's Subaru telescope on Mauna Kea, Hawaii are blue.
› Full image and caption


November 21, 2013

Astronomers using the combined power of the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile and NASA's Hubble and Spitzer space telescopes have discovered a far-flung trio of primitive galaxies nestled inside an enormous blob of primordial gas nearly 13 billion light-years from Earth. It's possible the trio will eventually merge into a single galaxy similar to our own Milky Way.


"This exceedingly rare triple system, seen when the universe was only 800 million years old, provides important insights into the earliest stages of galaxy formation during a period known as 'cosmic dawn,' when the universe was first bathed in starlight," said Richard Ellis of the California Institute of Technology, Pasadena, a member of the research team.


Researchers first detected this object, which appeared to be a giant bubble of hot, ionized gas, in 2009. Dubbed Himiko (after a legendary queen of ancient Japan), it is nearly 10 times larger than typical galaxies of that era and comparable in size to our own Milky Way. Subsequent infrared observations with NASA's Spitzer Space Telescope provided more clues about the object's mass, suggesting Himiko might represent a single galaxy, which would make it uncharacteristically massive for that period of the early universe.


"The new observations revealed that, rather than a single galaxy, Himiko harbors three distinct, bright sources, whose intense star formation is heating and ionizing this giant cloud of gas," said Masami Ouchi, an associate professor at the University of Tokyo who led the international team of astronomers from Japan and the United States.


New data from ALMA, Hubble and Spitzer also led astronomers to speculate that Himiko could be made up almost entirely of primordial gas, a mixture of the light elements hydrogen and helium, which were created in the Big Bang event that gave birth to our universe. If correct, this would be a landmark discovery signaling the detection of a primordial galaxy seen during its formation.


The results are accepted for publication in the Astrophysical Journal.


Read the full ALMA news release online at: https://public.nrao.edu/news/pressreleases/infant-galaxies-merge-near-cosmic-dawn .


Read the Caltech news release at: http://www.caltech.edu/content/himiko-and-cosmic-dawn .


NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .


ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


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Three Questions About Comet ISON

Three Questions About Comet ISON:

Comet ISON appeared in the higher-resolution HI-1 camera on NASA's STEREO-A spacecraft.
Comet ISON appeared in the higher-resolution HI-1 camera on NASA's STEREO-A spacecraft. Dark "clouds" coming from the right are more dense areas in the solar wind, causing ripples in Comet Encke's tail. Using comet tails as tracers can provide valuable data about solar wind conditions near the sun. Image Credit:
Karl Battams/NASA/STEREO/CIOC
› Larger image

November 25, 2013

Don Yeomans, a senior research scientist at JPL, keeps a watchful eye on near-Earth objects -- asteroids, comets and other space rocks. Yeomans heads a group charged by NASA to watch for objects whose orbits bring them close to Earth.


Below is a comet ISON Q&A with Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory, Pasadena, Calif.


What is so interesting about comet ISON?

There's great interest in comet ISON for a couple of reasons. First of all, it's coming from the very edge of our solar system so it stills retains the primordial ices from which it formed four-and-a-half billion years ago. It's been traveling from the outer edge of the solar system for about five-and-a-half million years to reach us in the inner solar system, and it's going to make an extremely close approach to the sun and hence could become very bright and possibly a very easy naked-eye object in early December.


What will happen to comet ISON on Thanksgiving?

So there are three possibilities when this comet rounds the sun on Thanksgiving Day 2013 [Nov. 28]. It could be tough enough to survive the passage of the sun and be a fairly bright naked-eye object in the early morning sky in the first week of December. Or, the sun could actually pull it apart. The tidal forces could actually pull this comet apart and so it becomes several chunks rounding the sun and putting on a great show again in early December. Or, if the comet is very weak, it could break up into a cloud of dust and be a complete bust in December.


Do comets like ISON present a scientific opportunity?

There is going to be a small army of amateur and professional astronomers on the Earth, and spacecraft are going to be observing this object near the sun. So we're going to find out a great deal about what this comet is made of, and hence we are going to find out a great deal about what the solar system was like four-and-a-half billion years ago.


To learn more about comet ISON, go to www.nasa.gov/ison .

NASA's Near-Earth Object Program at NASA Headquarters, Washington, manages and funds the search, study and monitoring of asteroids and comets whose orbits periodically bring them close to Earth. JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.


More information about asteroids and near-Earth objects is available at: http://neo.jpl.nasa.gov/ , http://www.jpl.nasa.gov/asteroidwatch and via Twitter at http://www.twitter.com/asteroidwatch .

DC Agle 818-393-9011

Jet Propulsion Laboratory, Pasadena, Calif.

agle@jpl.nasa.gov


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Do Black Holes Come in Size Medium?

Do Black Holes Come in Size Medium?:

Topsy Turvy Black Holes
The magenta spots in this image show two black holes in the spiral galaxy called NGC 1313, or the Topsy Turvy galaxy. Both black holes belong to a class called ultraluminous X-ray sources, or ULXs. The magenta X-ray data come from NASA's Nuclear Spectroscopic Telescopic Array, and are overlaid on a visible image from the Digitized Sky Survey. Image credit: NASA/JPL-Caltech/IRAP
› Full image and caption

November 26, 2013

Black holes can be petite, with masses only about 10 times that of our sun -- or monstrous, boasting the equivalent in mass up to 10 billion suns. Do black holes also come in size medium? NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, is busy scrutinizing a class of black holes that may fall into the proposed medium-sized category.


"Exactly how intermediate-sized black holes would form remains an open issue," said Dominic Walton of the California Institute of Technology, Pasadena. "Some theories suggest they could form in rich, dense clusters of stars through repeated mergers, but there are a lot of questions left to be answered."


The largest black holes, referred to as supermassive, dominate the hearts of galaxies. The immense gravity of these black holes drags material toward them, forcing the material to heat up and release powerful X-rays. Small black holes dot the rest of the galactic landscape. They form under the crush of collapsing, dying stars bigger than our sun.


Evidence for medium-sized black holes lying somewhere between these two extremes might come from objects called ultraluminous X-ray sources, or ULXs. These are pairs of objects in which a black hole ravenously feeds off a normal star. The feeding process is somewhat similar to what happens around supermassive black holes, but isn't as big and messy. In addition, ULXs are located throughout galaxies, not at the cores.


The bright glow of X-rays coming from ULXs is too great to be the product of typical small black holes. This and other evidence indicates the objects may be intermediate in mass, with 100 to 10,000 times the mass of our sun. Alternatively, an explanation may lie in some kind of exotic phenomenon involving extreme accretion, or "feeding," of a black hole.


NuSTAR is joining with other telescopes to take a closer look at ULXs. It's providing the first look at these objects in focused, high-energy X-rays, helping to get better estimates of their masses and other characteristics.


In a new paper from Walton and colleagues accepted for publication in the Astrophysical Journal, the astronomers report serendipitously finding a ULX that had gone largely unnoticed before. They studied the object, which lies in the Circinus spiral galaxy 13 million light-years away, not only with NuSTAR but also with the European Space Agency's XMM-Newton satellite. Archival data from NASA's Chandra, Swift and Spitzer space telescopes as well as Japan's Suzaku satellite, were also used for further studies. "We went to town on this object, looking at a range of epochs and wavelengths," said Walton.


The results indicate the black hole in question is about 100 times the mass of the sun, putting it right at the border between small and medium black holes.


In another accepted Astrophysical Journal paper, Matteo Bachetti of the Institut de Recherche en Astrophysique et Planétologie and colleagues looked at two ULXs in NGC 1313, a spiral galaxy known as the "Topsy Turvy galaxy," also about 13 million light-years way.


These are among the best-studied ULXs known. A single viewing with NuSTAR showed that the black holes didn't fit with models of medium-size black holes. As a result, the researchers now think both ULXs harbor small, stellar-mass black holes. One of the objects is estimated to be big for its size category, at 70 to 100 solar masses.


"It's possible that these objects are ultraluminous because they are accreting material at a high rate and not because of their size," said Bachetti. "If intermediate-mass black holes are out there, they are doing a good job of hiding from us."


NuSTAR is a Small Explorer mission led by Caltech and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation, Dulles, Va. Its instrument was built by a consortium including Caltech; JPL; the University of California, Berkeley; Columbia University, New York; NASA's Goddard Space Flight Center, Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence Livermore National Laboratory, Livermore, Calif.; ATK Aerospace Systems, Goleta, Calif., and with support from the Italian Space Agency (ASI) Science Data Center.


NuSTAR's mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located at Malindi, Kenya. The mission's outreach program is based at Sonoma State University, Rohnert Park, Calif. NASA's Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


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Scientists Seek Other Scientists for Cosmology Problem

Scientists Seek Other Scientists for Cosmology Problem:

Warped Galaxies Quiz
Can you match each galaxy in the top row with its warped counterpart in the bottom row? For example, is the warped version of galaxy A in box D, E, or F? › Click for full-size quiz image  |  › See answers

November 26, 2013

How do you measure something that is invisible? It's a challenging task, but astronomers have made progress on one front: the study of dark matter and dark energy, two of the most mysterious substances in our cosmos. Dark matter is intermixed with normal matter, but it gives off no light, making it impossible to see. Dark energy is even more slippery, yet scientists think it works against gravity to pull our universe apart at the seams.


Now for the third time, an innovative competition has begun again with the goal of finding better tools for probing dark matter and dark energy. Called GREAT3, which stands for GRavitational lEnsing Accuracy Testing 3, the event is sponsored by NASA's Jet Propulsion Laboratory, Pasadena, Calif., and a European Union Network of Excellence called Pattern Analysis, Statistical Modeling and Computation Learning 2 (PASCAL2).


The idea behind the challenge is to spur scientists, including those from fields outside astronomy, to come up with new insight into the problems of measuring dark matter and dark energy. Contestants are asked to solve galaxy puzzles involving millions of images from NASA's Hubble Space Telescope. A better understanding of the "dark side of the cosmos" may reveal new information about the very fabric and fate of our universe.


The first two challenges were a big success, attracting new brainpower to the field, including scientists from machine learning and particle physics. Machine learning involves programming computers to learn on their own using actual data from the real world. It has several applications, such as facial-recognition software, medical diagnostics and spam filtering, to name a few.


"Other data scientists have been thinking about the same type of algorithms we need for our cosmology tools for a long time," said Jason Rhodes of JPL. "We want to acquire that knowledge and see this field grow."


One of the most powerful tools for studying dark matter and dark energy is gravitational lensing. When dark matter lies between us and a distant galaxy, the light of the galaxy can be warped by the gravity from the dark matter. By measuring this warping, scientists can map dark matter, despite it being invisible. What's more, by looking at the distribution of dark and normal matter in our universe, scientists can get a better handle on dark energy and how it battles gravity to slow the growth of galactic structures.


In some cases of gravitational lensing, galaxies look wacky, as if seen in a funhouse mirror, or they appear multiple times. This is referred to as strong lensing. But in most cases, called weak lensing, the warping effects are tiny and impossible to see by eye.


The GREAT3 challenge is designed to improve methods for measuring weak lensing in preparation for future dark matter/dark energy missions, such as the European Space Agency's Euclid, in which NASA plays an important role, and the National Academy of Science's highest priority for NASA, WFIRST -- also known as the WFIRST-AFTA mission, which stands for Wide-Field Infrared Survey Telescope-Astrophysics Focused Telescope Assets.


The millions of images given to GREAT3 contestants show galaxies that have been artificially warped via weak lensing. The puzzle is to figure out precisely how the galaxy images were warped, a complex task that involves looking for patterns and sifting out artificial warping effects caused by telescope optics and the atmosphere.


The winner will be announced in May 2014 and will receive $3,000 worth of computing equipment, the perfect gift for programmers hoping to crack more cosmic codes.


"With these contests, we have seen new ideas seeping into our field," said Rachel Mandelbaum of Carnegie Mellon University, Pittsburgh, who is working with Rhodes and Barnaby Rowe of UCL (University College London), England, to organize the challenge, along with a special committee. "It's a fun problem to work on and it's a problem that needs to be solved."


A visual quiz involving strongly lensed, or warped, galaxies is at: http://www.nasa.gov/jpl/news/galaxy20131126.html .


More information about the competition is online at: http://great3challenge.info/ .


The California Institute of Technology, Pasadena, manages JPL for NASA.

Whitney Clavin (818) 354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


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NASA Holds Google+ Hangout on Cassini's Findings at Saturn

NASA Holds Google+ Hangout on Cassini's Findings at Saturn:

The Day the Earth Smiled
On July 19, 2013, in an event celebrated the world over, NASA's Cassini spacecraft slipped into Saturn's shadow and turned to image the planet, seven of its moons, its inner rings -- and, in the background, our home planet, Earth. Image credit: NASA/JPL-Caltech/SSI
› Full image and caption


December 02, 2013

NASA will host a Google+ Hangout at 12:30 p.m. PST (3:30 p.m. EST) on Wednesday, Dec. 4, to discuss images of Saturn taken by the agency's Cassini spacecraft. The Hangout also will look ahead to the next few years of the Cassini mission.


The event will also be broadcast live on NASA Television and streamed on the agency's website.


The panelists are:

-- Kunio Sayanagi, Cassini imaging team associate, Hampton University, Va.

-- Carolyn Porco, Cassini imaging team lead, Space Science Institute, Boulder, Colo.

-- Linda Spilker, Cassini project scientist, NASA's Jet Propulsion Laboratory, Pasadena, Calif.

-- Earl Maize, Cassini program manager, JPL



Reporters and the public can ask questions on the Google+ Hangout event page, in the chat box on the Ustream site and via Twitter using the hashtag #askCassini.


The Google+ Hangout will be available at: http://bit.ly/askcassini .


For NASA TV streaming video, downlink and scheduling information, visit:
http://www.nasa.gov/nasatv .


The event will be streamed live on Ustream with a moderated chat available at: http://www.ustream.com/nasajpl2 .


For more information about the Cassini mission, visit: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


Dwayne Brown 202-358-1726

NASA Headquarters, Washington

dwayne.c.brown@nasa.gov


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Massive Black Hole Duo: Possible Sighting by NASA's WISE

Massive Black Hole Duo: Possible Sighting by NASA's WISE:

Two Black Holes on Way to Becoming One
Two black holes are entwined in a gravitational tango in this artist's conception. Supermassive black holes at the hearts of galaxies are thought to form through the merging of smaller, yet still massive black holes, such as the ones depicted here. Image credit: NASA
› Full image and caption

December 03, 2013

Astronomers have spotted what appear to be two supermassive black holes at the heart of a remote galaxy, circling each other like dance partners. The incredibly rare sighting was made with the help of NASA's Wide-field Infrared Survey Explorer, or WISE.


Follow-up observations with the Australian Telescope Compact Array near Narrabri, Australia, and the Gemini South telescope in Chile, revealed unusual features in the galaxy, including a lumpy jet thought to be the result of one black hole causing the jet of the other to sway.


"We think the jet of one black hole is being wiggled by the other, like a dance with ribbons," said Chao-Wei Tsai of NASA's Jet Propulsion Laboratory, Pasadena, Calif., who is lead author of a paper on the findings appearing in the Dec. 10 issue of Astrophysical Journal. "If so, it is likely the two black holes are fairly close and gravitationally entwined."


The findings could teach astronomers more about how supermassive black holes grow by merging with each other.


The WISE satellite scanned the entire sky twice in infrared wavelengths before being put into hibernation in 2011. NASA recently gave the spacecraft a second lease on life, waking it up to search for asteroids, in a project called NEOWISE.


The new study took advantage of previously released all-sky WISE data. Astronomers sifted through images of millions of actively feeding supermassive black holes spread throughout our sky before an oddball, also known as WISE J233237.05-505643.5, jumped out.


"At first we thought this galaxy's unusual properties seen by WISE might mean it was forming new stars at a furious rate," said Peter Eisenhardt, WISE project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and a co-author of the study. "But on closer inspection, it looks more like the death spiral of merging giant black holes."


Almost every large galaxy is thought to harbor a supermassive black hole filled with the equivalent in mass of up to billions of suns. How did the black holes grow so large? One way is by swallowing ambient materials. Another way is through galactic cannibalism. When galaxies collide, their massive black holes sink to the center of the new structure, becoming locked in a gravitational tango. Eventually, they merge into one even-more-massive black hole.


The dance of these black hole duos starts out slowly, with the objects circling each other at a distance of about a few thousand light-years. So far, only a few handfuls of supermassive black holes have been conclusively identified in this early phase of merging. As the black holes continue to spiral in toward each other, they get closer, separated by just a few light-years.


It is these close-knit black holes, also called black hole binaries, that have been the hardest to find. The objects are usually too small to be resolved even by powerful telescopes. Only a few strong candidates have been identified to date, all relatively nearby. The new WISE J233237.05-505643.5 is a new candidate, and located much farther away, at 3.8 billion light-years from Earth.


Radio images with the Australian Telescope Compact Array were key to identifying the dual nature of WISE J233237.05-505643.5. Supermassive black holes at the cores of galaxies typically shoot out pencil-straight jets, but, in this case, the jet showed a zigzag pattern. According to the scientists, a second massive black hole could, in essence, be pushing its weight around to change the shape of the other black hole's jet.


Visible-light spectral data from the Gemini South telescope in Chile showed similar signs of abnormalities, thought to be the result of one black hole causing disk material surrounding the other black hole to clump. Together, these and other signs point to what is probably a fairly close-knit set of circling black holes, though the scientists can't say for sure how much distance separates them.


"We note some caution in interpreting this mysterious system," said Daniel Stern of JPL, a co-author of the study. "There are several extremely unusual properties to this system, from the multiple radio jets to the Gemini data, which indicate a highly perturbed disk of accreting material around the black hole, or holes. Two merging black holes, which should be a common event in the universe, would appear to be simplest explanation to explain all the current observations."


The final stage of merging black holes is predicted to send gravitational waves rippling through space and time. Researchers are actively searching for these waves using arrays of dead stars called pulsars in hopes of learning more about the veiled black hole dancers (see http://www.nasa.gov/centers/jpl/news/pulsar20131106.html ).


The technical paper is online at http://arxiv.org/abs/1310.2257 .


NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages and operates the WISE mission for NASA's Science Mission Directorate. The WISE mission was selected competitively under NASA's Explorers Program managed by the agency's Goddard Space Flight Center in Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory in Logan, Utah. The spacecraft was built by Ball Aerospace & Technologies Corp. in 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 .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


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NASA's Dawn Fills out its Ceres Dance Card

NASA's Dawn Fills out its Ceres Dance Card:

On the Way to Ceres
This artist's concept shows NASA's Dawn spacecraft heading toward the dwarf planet Ceres. Dawn spent nearly 14 months orbiting Vesta, the second most massive object in the main asteroid belt between Mars and Jupiter, from 2011 to 2012. It is heading towards Ceres, the largest member of the asteroid belt. When Dawn arrives, it will be the first spacecraft to go into orbit around two destinations in our solar system beyond Earth. Image credit: NASA/JPL-Caltech
› Full image and caption

December 03, 2013

It's going to be a ball when NASA's Dawn spacecraft finally arrives at the dwarf planet Ceres, and mission managers have now inked in the schedule on Dawn's dance card.


Dawn has been cruising toward Ceres, the largest object in the main asteroid belt between Mars and Jupiter, since September 2012. That's when it departed from its first dance partner, Vesta.


Ceres presents an icy -- possibly watery -- counterpoint to the dry Vesta, where Dawn spent almost 14 months. Vesta and Ceres are two of the largest surviving protoplanets -- bodies that almost became planets -- and will give scientists clues about the planet-forming conditions at the dawn of our solar system.


When Dawn enters orbit around Ceres, it will be the first spacecraft to see a dwarf planet up-close and the first spacecraft to orbit two solar system destinations beyond Earth.


"Our flight plan around Ceres will be choreographed to be very similar to the strategy that we successfully used around Vesta," said Bob Mase, Dawn's project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This approach will build on that and enable scientists to make direct comparisons between these two giants of the asteroid belt."


As a prelude, the team will begin approach operations in late January 2015. The next month, Ceres will be big enough in Dawn's view to be imaged and used for navigation purposes. Dawn will arrive at Ceres -- or, more accurately, it will be captured by Ceres' gravity -- in late March or the beginning of April 2015.


Dawn will make its first full characterization of Ceres later in April, at an altitude of about 8,400 miles (13,500 kilometers) above the icy surface. Then, it will spiral down to an altitude of about 2,750 miles (4,430 kilometers), and obtain more science data in its survey science orbit. This phase will last for 22 days, and is designed to obtain a global view of Ceres with Dawn's framing camera, and global maps with the visible and infrared mapping spectrometer (VIR).


Dawn will then continue to spiral its way down to an altitude of about 920 miles (1,480 kilometers), and in August 2015 will begin a two-month phase known as the high-altitude mapping orbit. During this phase, the spacecraft will continue to acquire near-global maps with the VIR and framing camera at higher resolution than in the survey phase. The spacecraft will also image in "stereo" to resolve the surface in 3-D.


Then, after spiraling down for two months, Dawn will begin its closest orbit around Ceres in late November, at a distance of about 233 miles (375 kilometers). The dance at low-altitude mapping orbit will be a long waltz -- three months -- and is specifically designed to acquire data with Dawn's gamma ray and neutron detector (GRaND) and gravity investigation. GRaND will reveal the signatures of the elements on and near the surface. The gravity experiment will measure the tug of the dwarf planet, as monitored by changes in the high-precision radio link to NASA's Deep Space Network on Earth.


At this low-altitude mapping orbit, Dawn will begin using a method of pointing control that engineers have dubbed "hybrid" mode because it utilizes a combination of reaction wheels and thrusters to point the spacecraft. Up until this final mission phase, Dawn will have used just the small thruster jets, which use a fuel called hydrazine, to control its orientation and pointing. While it is possible to explore Ceres completely using only these jets, mission managers want to conserve precious fuel. At this lowest orbit, using two of the reaction wheels to help with pointing will provide the biggest hydrazine savings. So Dawn will be spinning up two of the gyroscope-like devices to aid the thrusters.


In 2011, the Dawn team prepared the capability to operate in a hybrid mode, but it wasn't needed during the Vesta mission. It was only when a second (of four) reaction wheels developed excessive friction while Dawn was leaving Vesta in 2012 that mission managers decided to use the hybrid mode at Ceres. To prove the technique works, Dawn engineers completed a 27-hour in-flight test of the hybrid mode, ending on Nov. 13. It operated just as expected.


"The successful test of this new way to control our orientation gives us great confidence that we'll have a steady hand at Ceres, which will enable us to get really close to a world that we only know now as a fuzzy dot amidst the stars," said Marc Rayman, Dawn's chief engineer and mission director, based at JPL.


Of course, mission planners have built some extra days into the schedule to account for the small uncertainty in the efficiency of the solar arrays at such a large distance from the sun, where sunlight will be very faint. The solar arrays provide power to the ion propulsion system, in addition to operating power for the spacecraft and instruments. Mission planners also account for potential variations in the gravity field of Ceres, which will not be known precisely until Dawn measures them.


"We are expecting changes when we get to Ceres and, fortunately, we built a very capable spacecraft and developed flexible plans to accommodate the unknowns," said Rayman. "There's great excitement in the unexpected -- that's part of the thrill of exploration."


Starting on Dec. 27, Dawn will be closer to Ceres than it will be to Vesta.


"This transition makes us eager to see what secrets Ceres will reveal to us when we get up close to this ancient, giant, icy body," said Christopher Russell, Dawn's principal investigator, based at UCLA. "While Ceres is a lot bigger than the candidate asteroids that NASA is working on sending humans to, many of these smaller bodies are produced by collisions with larger asteroids such as Ceres and Vesta. It is of much interest to determine the nature of small asteroids produced in collisions with Ceres. These might be quite different from the small rocky asteroids associated with Vesta collisions."


Dawn's mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Ala. UCLA is responsible for overall Dawn mission science. Orbital Sciences Corp. in Dulles, Va., designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team. The California Institute of Technology in Pasadena manages JPL for NASA.


To learn more about hybrid mode at Ceres, read Rayman's Dawn Journal [link].


For more information about Dawn, visit: http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov .


To learn more about hybrid mode at Ceres, read Rayman's Dawn Journal .

Jia-Rui Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


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NASA's Cassini Spacecraft Obtains Best Views of Saturn Hexagon

NASA's Cassini Spacecraft Obtains Best Views of Saturn Hexagon:

In Full View: Saturn's Streaming Hexagon
This colorful view from NASA's Cassini mission is the highest-resolution view of the unique six-sided jet stream at Saturn's north pole known as "the hexagon." This movie, made from images obtained by Cassini's imaging cameras, is the first to show the hexagon in color filters, and the first movie to show a complete view from the north pole down to about 70 degrees north latitude. Image credit: NASA/JPL-Caltech/SSI/Hampton University
› Full image and caption


December 04, 2013

NASA's Cassini spacecraft has obtained the highest-resolution movie yet of a unique six-sided jet stream, known as the hexagon, around Saturn's north pole.


This is the first hexagon movie of its kind, using color filters, and the first to show a complete view of the top of Saturn down to about 70 degrees latitude. Spanning about 20,000 miles (30,000 kilometers) across, the hexagon is a wavy jet stream of 200-mile-per-hour winds (about 322 kilometers per hour) with a massive, rotating storm at the center. There is no weather feature exactly, consistently like this anywhere else in the solar system.


"The hexagon is just a current of air, and weather features out there that share similarities to this are notoriously turbulent and unstable," said Andrew Ingersoll, a Cassini imaging team member at the California Institute of Technology in Pasadena. "A hurricane on Earth typically lasts a week, but this has been here for decades -- and who knows -- maybe centuries."


Weather patterns on Earth are interrupted when they encounter friction from landforms or ice caps. Scientists suspect the stability of the hexagon has something to do with the lack of solid landforms on Saturn, which is essentially a giant ball of gas.


Better views of the hexagon are available now because the sun began to illuminate its interior in late 2012. Cassini captured images of the hexagon over a 10-hour time span with high-resolution cameras, giving scientists a good look at the motion of cloud structures within.


They saw the storm around the pole, as well as small vortices rotating in the opposite direction of the hexagon. Some of the vortices are swept along with the jet stream as if on a racetrack. The largest of these vortices spans about 2,200 miles (3,500 kilometers), or about twice the size of the largest hurricane recorded on Earth.


Scientists analyzed these images in false color, a rendering method that makes it easier to distinguish differences among the types of particles suspended in the atmosphere -- relatively small particles that make up haze -- inside and outside the hexagon.


"Inside the hexagon, there are fewer large haze particles and a concentration of small haze particles, while outside the hexagon, the opposite is true," said Kunio Sayanagi, a Cassini imaging team associate at Hampton University in Virginia. "The hexagonal jet stream is acting like a barrier, which results in something like Earth's Antarctic ozone hole."


The Antarctic ozone hole forms within a region enclosed by a jet stream with similarities to the hexagon. Wintertime conditions enable ozone-destroying chemical processes to occur, and the jet stream prevents a resupply of ozone from the outside. At Saturn, large aerosols cannot cross into the hexagonal jet stream from outside, and large aerosol particles are created when sunlight shines on the atmosphere. Only recently, with the start of Saturn's northern spring in August 2009, did sunlight begin bathing the planet's northern hemisphere.


"As we approach Saturn's summer solstice in 2017, lighting conditions over its north pole will improve, and we are excited to track the changes that occur both inside and outside the hexagon boundary," said Scott Edgington, Cassini deputy project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.


A black-and-white version of the imaging camera movie and movies obtained by Cassini's visual and infrared mapping spectrometer are also tools Cassini scientists can use to look at wind speeds and the mini-storms inside the jet stream.


Cassini launched in 1997 and arrived at Saturn on July 1, 2004. Its mission is scheduled to end in September 2017. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter and its two onboard cameras. The imaging team is based at the Space Science Institute, Boulder, Colo.


A Google+ Hangout to discuss these results and other Cassini images will take place today at 12:30 p.m. PST (3:30 p.m. EST): http://bit.ly/askcassini .


The event will be broadcast live on NASA Television and streamed on the agency's website. For information on NASA TV, visit: http://www.nasa.gov/ntv .


The event will also be streamed live on Ustream with a moderated chat available at: http://www.ustream.tv/nasajpl2 .


Questions can be asked on the Google Hangout event page, in the chat box on the Ustream site and via Twitter using the hashtag #askCassini.


More information about Cassini is available at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


Dwayne Brown 202-358-1726

NASA Headquarters, Washington

dwayne.c.brown@nasa.gov


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