Tuesday, July 22, 2014

NASA Invites Social Media Fans to Earth Science Event

NASA Invites Social Media Fans to Earth Science Event:

This view of Earth comes from NASA's Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite.
This view of Earth comes from NASA's Moderate Resolution Imaging Spectroradiometer aboard the Terra satellite. Larger image
› Larger image


September 16, 2013

PASADENA, Calif. - NASA is inviting its social media followers to apply for participation in a two-day NASA Social on Nov. 4 and 5 at the agency's Jet Propulsion Laboratory in Pasadena, Calif. The event will highlight NASA and JPL's role in studying Earth and its climate and will preview three Earth-observing missions JPL is preparing for launch in 2014.


The event will offer people who connect with NASA through Twitter, Facebook, Google+ and other social networks the opportunity to interact with scientists and engineers working on upcoming missions and participate in hands-on demonstrations. Participants will also interact with fellow tweeps, space enthusiasts and members of NASA's social media team. They will get a behind-the-scenes tour of JPL, including:


-- The Spacecraft Assembly Facility, where hardware for two upcoming Earth missions is currently under construction. This clean room is also where NASA's Voyager and Cassini spacecraft and the Curiosity, Opportunity and Spirit Mars rovers were built and tested.
-- The JPL Earth Science Center, where data from many of the agency's Earth-observing missions are showcased in interactive displays.
-- The Mission Control Center of NASA's Deep Space Network, where engineers "talk to" spacecraft across the solar system and in interstellar space.
-- The JPL Mars Yard, where engineers and scientists test engineering models of NASA's Curiosity rover in a sandy, Mars-like environment.


Registration for the NASA Social is open until noon PDT (3 p.m. EDT) on Wednesday, Sept. 18. NASA will randomly select at least 100 participants from online registrations.
More information on NASA Socials and the application for the Nov. 4/5 event are online at: http://www.nasa.gov/social .


The two NASA/JPL Earth-observing missions being assembled at JPL are the Soil Moisture Active Passive (SMAP) spacecraft and ISS-RapidScat. SMAP will produce global maps of soil moisture for tracking water availability around our planet. ISS-RapidScat is a scatterometer instrument that will be mounted outside the International Space Station to measure ocean surface wind speeds and directions. ISS-RapidScat is scheduled to launch first, in April 2014, with SMAP scheduled to launch in October 2014.


A third NASA/JPL Earth mission, the Orbiting Carbon Observatory-2 (OCO-2), scheduled to launch in July 2014, is in final assembly and testing at an Orbital Sciences Corp. facility in Gilbert, Ariz. The mission will be NASA's first dedicated Earth remote-sensing satellite to study atmospheric carbon dioxide from space.


To join and track the conversation online during the NASA Socials, follow the hashtag #NASASocial.


More information about connecting and collaborating with NASA is at: http://www.nasa.gov/connect .


For more on SMAP, visit: http://smap.jpl.nasa.gov/ .


For more on ISS-RapidScat, visit: http://www.nasa.gov/mission_pages/station/research/experiments/ISSRapidScat.html and http://winds.jpl.nasa.gov/missions/RapidScat/ .


For more on OCO-2, visit: http://oco.jpl.nasa.gov/ .


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

Courtney O'Connor 818-354-2274

Jet Propulsion Laboratory, Pasadena, Calif.

oconnor@jpl.nasa.gov


John Yembrick/Jason Townsend 650-604-2065 / 202-358-0359

NASA Headquarters, Washington

john.yembrick@nasa.gov / jason.c.townsend@nasa.gov


2013-280
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NASA's Deep Space Comet Hunter Mission Comes to an End

NASA's Deep Space Comet Hunter Mission Comes to an End:

Artist's concept of NASA's Deep Impact spacecraft.
Artist's concept of NASA's Deep Impact spacecraft. Image Credit: NASA/JPL-Caltech.
› Larger image

September 20, 2013

PASADENA, Calif. - After almost 9 years in space that included an unprecedented July 4th impact and subsequent flyby of a comet, an additional comet flyby, and the return of approximately 500,000 images of celestial objects, NASA's Deep Impact mission has ended.

The project team at NASA's Jet Propulsion Laboratory in Pasadena, Calif., has reluctantly pronounced the mission at an end after being unable to communicate with the spacecraft for over a month. The last communication with the probe was Aug. 8. Deep Impact was history's most traveled comet research mission, going about 4.7 billion miles (7.58 billion kilometers).

"Deep Impact has been a fantastic, long-lasting spacecraft that has produced far more data than we had planned," said Mike A'Hearn, the Deep Impact principal investigator at the University of Maryland in College Park. "It has revolutionized our understanding of comets and their activity."

Deep Impact successfully completed its original bold mission of six months in 2005 to investigate both the surface and interior composition of a comet, and a subsequent extended mission of another comet flyby and observations of planets around other stars that lasted from July 2007 to December 2010. Since then, the spacecraft has been continually used as a space-borne planetary observatory to capture images and other scientific data on several targets of opportunity with its telescopes and instrumentation.

Launched in January 2005, the spacecraft first traveled about 268 million miles (431 million kilometers) to the vicinity of comet Tempel 1. On July 3, 2005, the spacecraft deployed an impactor into the path of comet to essentially be run over by its nucleus on July 4. This caused material from below the comet's surface to be blasted out into space where it could be examined by the telescopes and instrumentation of the flyby spacecraft. Sixteen days after that comet encounter, the Deep Impact team placed the spacecraft on a trajectory to fly back past Earth in late December 2007 to put it on course to encounter another comet, Hartley 2 in November 2010.

"Six months after launch, this spacecraft had already completed its planned mission to study comet Tempel 1," said Tim Larson, project manager of Deep Impact at JPL. "But the science team kept finding interesting things to do, and through the ingenuity of our mission team and navigators and support of NASA's Discovery Program, this spacecraft kept it up for more than eight years, producing amazing results all along the way."

The spacecraft's extended mission culminated in the successful flyby of comet Hartley 2 on Nov. 4, 2010. Along the way, it also observed six different stars to confirm the motion of planets orbiting them, and took images and data of Earth, the moon and Mars. These data helped to confirm the existence of water on the moon, and attempted to confirm the methane signature in the atmosphere of Mars. One sequence of images is a breathtaking view of the moon transiting across the face of Earth.

In January 2012, Deep Impact performed imaging and accessed the composition of distant comet C/2009 P1 (Garradd). It took images of comet ISON this year and collected early images of ISON in June.

After losing contact with the spacecraft last month, mission controllers spent several weeks trying to uplink commands to reactivate its onboard systems. Although the exact cause of the loss is not known, analysis has uncovered a potential problem with computer time tagging that could have led to loss of control for Deep Impact's orientation. That would then affect the positioning of its radio antennas, making communication difficult, as well as its solar arrays, which would in turn prevent the spacecraft from getting power and allow cold temperatures to ruin onboard equipment, essentially freezing its battery and propulsion systems.

"Despite this unexpected final curtain call, Deep Impact already achieved much more than ever was envisioned," said Lindley Johnson, the Discovery Program Executive at NASA Headquarters, and the Program Executive for the mission since a year before it launched. "Deep Impact has completely overturned what we thought we knew about comets and also provided a treasure trove of additional planetary science that will be the source data of research for years to come."

The mission is part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. JPL manages the Deep Impact mission for NASA's Science Mission Directorate in Washington. Ball Aerospace & Technologies Corp. of Boulder, Colo., built the spacecraft. The California Institute of Technology in Pasadena manages JPL for NASA.

To find out more about Deep Impact's scientific results, visit:

http://www.jpl.nasa.gov/news/news.php?release=2013-286

For more information about Deep Impact, visit:

http://www.nasa.gov/deepimpact

D.C. Agle 818-393-9011

Jet Propulsion Laboratory, Pasadena, Calif.

agle@jpl.nasa.gov

Dwayne Brown 202-358-1726

NASA Headquarters, Washington

dwayne.c.brown@nasa.gov


Lee Tune 301-405-4679
University of Maryland, College Park, Md.
ltune@umd.edu

2013-287
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How Engineers Revamped Spitzer to Probe Exoplanets

How Engineers Revamped Spitzer to Probe Exoplanets:

Spitzer Trains Its Eyes on Exoplanets
Over its ten years in space, NASA's Spitzer Space Telescope has evolved into a premier tool for studying exoplanets. The engineers and scientists behind Spitzer did not have this goal in mind when they designed the observatory back in the 1990s. But thanks to its extraordinary stability, and a series of engineering reworks after launch, Spitzer now has observational powers far beyond its original limits and expectations. Image credit: NASA/JPL-Caltech
› Full image and caption

September 24, 2013

Now approaching its 10th anniversary, NASA's Spitzer Space Telescope has evolved into a premier observatory for an endeavor not envisioned in its original design: the study of worlds around other stars, called exoplanets. While the engineers and scientists who built Spitzer did not have this goal in mind, their visionary work made this unexpected capability possible. Thanks to the extraordinary stability of its design and a series of subsequent engineering reworks, the space telescope now has observational powers far beyond its original limits and expectations.


"When Spitzer launched back in 2003, the idea that we would use it to study exoplanets was so crazy that no one considered it," said Sean Carey of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "But now the exoplanet science work has become a cornerstone of what we do with the telescope."


Spitzer views the universe in the infrared light that is a bit less energetic than the light our eyes can see. Infrared light can easily pass through stray cosmic gas and dust, allowing researchers to peer into dusty stellar nurseries, the centers of galaxies, and newly forming planetary systems.


This infrared vision of Spitzer's also translates into exoplanet snooping. When an exoplanet crosses or "transits" in front of its star, it blocks out a tiny fraction of the starlight. These mini-eclipses as glimpsed by Spitzer reveal the size of an alien world.


Exoplanets emit infrared light as well, which Spitzer can capture to learn about their atmospheric compositions. As an exoplanet orbits its sun, showing different regions of its surface to Spitzer's cameras, changes in overall infrared brightness can speak to the planet's climate. A decrease in brightness as the exoplanet then goes behind its star can also provide a measurement of the world's temperature.


While the study of the formation of stars and the dusty environments from which planets form had always been a cornerstone of Spitzer's science program, its exoplanet work only became possible by reaching an unprecedented level of sensitivity, beyond its original design specifications.


Researchers had actually finalized the telescope's design in 1996 before any transiting exoplanets had even been discovered. The high degree of precision in measuring brightness changes needed for observing transiting exoplanets was not considered feasible in infrared because no previous infrared instrument had offered anything close to what was needed.


Nevertheless, Spitzer was built to have excellent control over unwanted temperature variations and a better star-targeting pointing system than thought necessary to perform its duties. Both of these foresighted design elements have since paid dividends in obtaining the extreme precision required for studying transiting exoplanets.


The fact that Spitzer can still do any science work at all still can be credited to some early-in-the-game, innovative thinking. Spitzer was initially loaded with enough coolant to keep its three temperature-sensitive science instruments running for at least two-and-a-half years. This "cryo" mission ended up lasting more than five-and-a-half-years before exhausting the coolant.


But Spitzer's engineers had a built-in backup plan. A passive cooling system has kept one set of infrared cameras humming along at a super-low operational temperature of minus 407 degrees Fahrenheit (minus 244 Celsius, or 29 degrees above absolute zero). The infrared cameras have continued operating at full sensitivity, letting Spitzer persevere in a "warm" extended mission, so to speak, though still extremely cold by Earthly standards.


To stay so cool, Spitzer is painted black on the side that faces away from the sun, which enables the telescope to radiate away a maximum amount of heat into space. On the sun-facing side, Spitzer has a shiny coating that reflects as much of the heat from the sun and solar panels as possible. It is the first infrared telescope to use this innovative design and has set the standard for subsequent missions.


Fully transitioning Spitzer into an exoplanet spy required some clever modifications in-flight as well, long after it flew beyond the reach of human hands into an Earth-trailing orbit. Despite the telescope's excellent stability, a small "wobbling" remained as it pointed at target stars. The cameras also exhibited small brightness fluctuations when a star moved slightly across an individual pixel of the camera. The wobble, coupled with the small variation in the cameras, produced a periodic brightening and dimming of light from a star, making the delicate task of measuring exoplanet transits that much more difficult.


To tackle these issues, engineers first began looking into a source for the wobble. They noticed that the telescope's trembling followed an hourly cycle. This cycle, it turned out, coincided with that of a heater, which kicks on periodically to keep a battery aboard Spitzer at a certain temperature. The heater caused a strut between the star trackers and telescope to flex a bit, making the position of the telescope wobble compared to the stars being tracked.


Ultimately, in October 2010, the engineers figured out that the heater did not need to be cycled through its full hour and temperature range -- 30 minutes and about 50 percent of the heat would do. This tweak served to cut the telescope's wobble in half.


Spitzer's engineers and scientists were still not satisfied, however. In September 2011, they succeeded in repurposing Spitzer's Pointing Control Reference Sensor "Peak-Up" camera. This camera was used during the original cryo mission to put gathered infrared light precisely into a spectrometer and to perform routine calibrations of the telescope's star-trackers, which help point the observatory. The telescope naturally wobbles back and forth a bit as it stares at a particular target star or object. Given this unavoidable jitter, being able to control where light goes within the infrared camera is critical for obtaining precise measurements. The engineers applied the Peak-Up to the infrared camera observations, thus allowing astronomers to place stars precisely on the center of a camera pixel.


Since repurposing the Peak-Up Camera, astronomers have taken this process even further, by carefully "mapping" the quirks of a single pixel within the camera. They have essentially found a "sweet spot" that returns the most stable observations. About 90 percent of Spitzer's exoplanet observations are finely targeted to a sub-pixel level, down to a particular quarter of a pixel. "We can use the Peak-Up camera to position ourselves very precisely on the camera and put light right on the best part of a pixel," said Carey. "So you put the light on the sweet spot and just let Spitzer stare."


These three accomplishments -- the modified heater cycling, repurposed Peak-Up camera and the in-depth characterization of individual pixels in the camera -- have more than doubled Spitzer's stability and targeting, giving the telescope exquisite sensitivity when it comes to taking exoplanet measurements.


"Because of these engineering modifications, Spitzer has been transformed into an exoplanet-studying telescope," said Carey. "We expect plenty of great exoplanetary science to come from Spitzer in the future."


NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. 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://www.nasa.gov/spitzer or http://www.spitzer.caltech.edu .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-289
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NASA's Cassini Spacecraft Finds Ingredient of Household Plastic in Space

NASA's Cassini Spacecraft Finds Ingredient of Household Plastic in Space:

A Ring of Color
NASA's Cassini spacecraft looks toward the night side of Saturn's largest moon and sees sunlight scattering through the periphery of Titan's atmosphere and forming a ring of color. Image credit: NASA/JPL-Caltech/Space Science Institute
› Full image and caption

September 30, 2013

PASADENA, Calif. - NASA's Cassini spacecraft has detected propylene, a chemical used to make food-storage containers, car bumpers and other consumer products, on Saturn's moon Titan.


This is the first definitive detection of the plastic ingredient on any moon or planet, other than Earth.


A small amount of propylene was identified in Titan's lower atmosphere by Cassini's composite infrared spectrometer (CIRS). This instrument measures the infrared light, or heat radiation, emitted from Saturn and its moons in much the same way our hands feel the warmth of a fire.


Propylene is the first molecule to be discovered on Titan using CIRS. By isolating the same signal at various altitudes within the lower atmosphere, researchers identified the chemical with a high degree of confidence. Details are presented in a paper in the Sept. 30 edition of the Astrophysical Journal Letters.


"This chemical is all around us in everyday life, strung together in long chains to form a plastic called polypropylene," said Conor Nixon, a planetary scientist at NASA's Goddard Space Flight Center in Greenbelt, Md., and lead author of the paper. "That plastic container at the grocery store with the recycling code 5 on the bottom -- that's polypropylene."


CIRS can identify a particular gas glowing in the lower layers of the atmosphere from its unique thermal fingerprint. The challenge is to isolate this one signature from the signals of all other gases around it.


The detection of the chemical fills in a mysterious gap in Titan observations that dates back to NASA's Voyager 1 spacecraft and the first-ever close flyby of this moon in 1980.


Voyager identified many of the gases in Titan's hazy brownish atmosphere as hydrocarbons, the chemicals that primarily make up petroleum and other fossil fuels on Earth.


On Titan, hydrocarbons form after sunlight breaks apart methane, the second-most plentiful gas in that atmosphere. The newly freed fragments can link up to form chains with two, three or more carbons. The family of chemicals with two carbons includes the flammable gas ethane. Propane, a common fuel for portable stoves, belongs to the three-carbon family.


Previously, Voyager found propane, the heaviest member of the three-carbon family, and propyne, one of the lightest members. But the middle chemicals, one of which is propylene, were missing.


As researchers continued to discover more and more chemicals in Titan's atmosphere using ground- and space-based instruments, propylene was one that remained elusive. It was finally found as a result of more detailed analysis of the CIRS data.


"This measurement was very difficult to make because propylene's weak signature is crowded by related chemicals with much stronger signals," said Michael Flasar, Goddard scientist and principal investigator for CIRS. "This success boosts our confidence that we will find still more chemicals long hidden in Titan's atmosphere."


Cassini's mass spectrometer, a device that looks at the composition of Titan's atmosphere, had hinted earlier that propylene might be present in the upper atmosphere. However, a positive identification had not been made.


"I am always excited when scientists discover a molecule that has never been observed before in an atmosphere," said Scott Edgington, Cassini's deputy project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "This new piece of the puzzle will provide an additional test of how well we understand the chemical zoo that makes up Titan's atmosphere."


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. The CIRS team is based at Goddard.


For more information about the Cassini mission, visit: 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


Nancy Neal-Jones/Elizabeth Zubritsky

Goddard Space Flight Center, Greenbelt, Md.

301-286-0039/301-614-5438

nancy.n.jones@nasa.gov / elizabeth.a.zubritsky@nasa.gov


2013-295
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NASA Space Telescopes Find Patchy Clouds on Exotic World

NASA Space Telescopes Find Patchy Clouds on Exotic World:

Partially Cloudy Skies on Kepler-7b
Kepler-7b (left), which is 1.5 times the radius of Jupiter (right), is the first exoplanet to have its clouds mapped. The cloud map was produced using data from NASA's Kepler and Spitzer space telescopes. Image credit: NASA/JPL-Caltech/MIT
› Full image and caption

September 30, 2013

PASADENA, Calif. -- Astronomers using data from NASA's Kepler and Spitzer space telescopes have created the first cloud map of a planet beyond our solar system, a sizzling, Jupiter-like world known as Kepler-7b.


The planet is marked by high clouds in the west and clear skies in the east. Previous studies from Spitzer have resulted in temperature maps of planets orbiting other stars, but this is the first look at cloud structures on a distant world.


"By observing this planet with Spitzer and Kepler for more than three years, we were able to produce a very low-resolution 'map' of this giant, gaseous planet," said Brice-Olivier Demory of Massachusetts Institute of Technology in Cambridge. Demory is lead author of a paper accepted for publication in the Astrophysical Journal Letters. "We wouldn't expect to see oceans or continents on this type of world, but we detected a clear, reflective signature that we interpreted as clouds."


Kepler has discovered more than 150 exoplanets, which are planets outside our solar system, and Kepler-7b was one of the first. The telescope's problematic reaction wheels prevent it from hunting planets any more, but astronomers continue to pore over almost four years' worth of collected data.


Kepler's visible-light observations of Kepler-7b's moon-like phases led to a rough map of the planet that showed a bright spot on its western hemisphere. But these data were not enough on their own to decipher whether the bright spot was coming from clouds or heat. The Spitzer Space Telescope played a crucial role in answering this question.


Like Kepler, Spitzer can fix its gaze at a star system as a planet orbits around the star, gathering clues about the planet's atmosphere. Spitzer's ability to detect infrared light means it was able to measure Kepler-7b's temperature, estimating it to be between 1,500 and 1,800 degrees Fahrenheit (1,100 and 1,300 Kelvin). This is relatively cool for a planet that orbits so close to its star -- within 0.6 astronomical units (one astronomical unit is the distance from Earth and the sun) -- and, according to astronomers, too cool to be the source of light Kepler observed. Instead, they determined, light from the planet's star is bouncing off cloud tops located on the west side of the planet.


"Kepler-7b reflects much more light than most giant planets we've found, which we attribute to clouds in the upper atmosphere," said Thomas Barclay, Kepler scientist at NASA's Ames Research Center in Moffett Field, Calif. "Unlike those on Earth, the cloud patterns on this planet do not seem to change much over time -- it has a remarkably stable climate."


The findings are an early step toward using similar techniques to study the atmospheres of planets more like Earth in composition and size.


"With Spitzer and Kepler together, we have a multi-wavelength tool for getting a good look at planets that are billions of miles away," said Paul Hertz, director of NASA's Astrophysics Division in Washington. "We're at a point now in exoplanet science where we are moving beyond just detecting exoplanets, and into the exciting science of understanding them."


Kepler identified planets by watching for dips in starlight that occur as the planets transit, or pass in front of their stars, blocking the light. This technique and other observations of Kepler-7b previously revealed that it is one of the puffiest planets known: if it could somehow be placed in a tub of water, it would float. The planet was also found to whip around its star in just less than five days.


Explore all 900-plus exoplanet discoveries with NASA's "Eyes on Exoplanets," a fully rendered 3D visualization tool, available for download at http://eyes.nasa.gov/exoplanets. The program is updated daily with the latest findings from NASA's Kepler mission and ground-based observatories around the world as they search for planets like our own.


Other authors include: Julien de Wit, Nikole Lewis, Adras Zsom and Sara Seager of Massachusetts Institute of Technology; Jonathan Fortney of the University of California, Santa Cruz; Heather Knutson and Jean-Michel Desert of the California Institute of Technology, Pasadena; Kevin Heng of the University of Bern, Switzerland; Nikku Madhusudhan of Yale University, New Haven, Conn.; Michael Gillon of the University of Liège, Belgium; Vivien Parmentier of the French National Center for Scientific Research, France; and Nicolas Cowan of Northwestern University, Evanston, Ill. Lewis is also a NASA Sagan Fellow.


The technical paper is online at http://www.mit.edu/~demory/preprints/kepler-7b_clouds.pdf .


NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA. Science operations are conducted at the Spitzer Science Center at Caltech. 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 .


Ames is responsible for Kepler's ground system development, mission operations and science data analysis. JPL managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and was funded by the agency's Science Mission Directorate. For more information about the Kepler mission, visit: http://www.nasa.gov/kepler and http://www.kepler.nasa.gov .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


Michele Johnson 650-604-6982

Ames Research Center, Moffett Field, Calif.

michele.johnson@nasa.gov


Steve Cole 202-358-0918

NASA Headquarters, Washington

stephen.e.cole@nasa.gov


2013-296
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Rings, Dark Side of Saturn Glow in New Cassini Image

Rings, Dark Side of Saturn Glow in New Cassini Image:

This colorized mosaic from NASA's Cassini mission shows an infrared view of the Saturn system, backlit by the sun, from July 19, 2013.
This colorized mosaic from NASA's Cassini mission shows an infrared view of the Saturn system, backlit by the sun, from July 19, 2013. Image credit: NASA/JPL-Caltech/University of Arizona/Cornell
› Full image and caption

October 17, 2013

Story Highlights:


• The Cassini spacecraft scanned across Saturn and its rings when the sun was behind the planet and faint rings were easier to detect.

• This latest infrared image shows a strip about 340,000 miles (540,000 kilometers) across that includes the planet and its rings out to Saturn's second most distant ring.


PASADENA, Calif. -- The gauzy rings of Saturn and the dark side of the planet glow in newly released infrared images obtained by NASA's Cassini spacecraft.


"Looking at the Saturn system when it is backlit by the sun gives scientists a kind of inside-out view of Saturn that we don't normally see," said Matt Hedman, a participating scientist based at the University of Idaho, Moscow, Idaho. "The parts of Saturn's rings that are bright when you look at them from backyard telescopes on Earth are dark, and other parts that are typically dark glow brightly in this view."


The images are available at: http://www.jpl.nasa.gov/spaceimages/details.php?id=pia17468 and
http://www.jpl.nasa.gov/spaceimages/details.php?id=pia17469 .


It can be difficult for scientists to get a good look at the faint outer F, E and G rings, or the tenuous inner ring known as the D ring when light is shining directly on them. That's because they are almost transparent and composed of small particles that do not reflect light well. What's different about this viewing geometry?


• When these small particles are lit from behind, they show up like fog in the headlights of an oncoming vehicle.

• The C ring also appears relatively bright here; not because it is made of dust, but because the material in it -- mostly dirty water ice -- is translucent. In fact, in the 18th and 19th centuries, it was known as the "crepe ring" because of its supposed similarity to crepe paper.

• The wide, middle ring known as the B ring -- one of the easiest to see from Earth through telescopes because it is densely packed with chunks of bright water ice -- looks dark in these images because it is so thick that it blocks almost all of the sunlight shining behind it.


Infrared images also show thermal, or heat, radiation. While a visible-light image from this vantage point would simply show the face of the planet as dimly lit by sunlight reflected off the rings, Saturn glows brightly in this view because of heat from Saturn's interior.


In a second version of the image, scientists "stretched" or exaggerated the contrast of the data, which brings out subtleties not initially visible.


• Structures in the wispy E ring -- made from the icy breath of the moon Enceladus -- reveal themselves in this exaggerated view.


"We're busy working on analyzing the infrared data from this special view of the Saturn system," said Phil Nicholson, a visual and infrared mapping spectrometer team member from Cornell University, Ithaca, N.Y. "The infrared data should tell us more about the sizes of the particles which make up the D, E, F and G rings, and how these sizes vary with location in the rings, as well as providing clues as to their chemical composition."


Launched in 1997, Cassini has been exploring the Saturn system for more than nine years with a suite of instruments that also includes visible-light cameras, ultraviolet and infrared spectrometers, as well as magnetic field and charged particle sensors. Scientists working with the visible light cameras are still busy putting together and analyzing their mosaic -- or multi-image picture -- of the Saturn system.


"Cassini's long-term residency at the ringed planet means we've been able to observe change over nearly half a Saturn-year (one Saturn-year is equal to almost 30 Earth-years) with a host of different tools," said Linda Spilker, Cassini project scientist, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "Earth looks different from season to season and Saturn does, too. We can't wait to see how those seasonal changes affect the dance of icy particles as we continue to observe in Saturn's rings with all of Cassini's different 'eyes.'"


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, Washington. The California Institute of Technology in Pasadena manages JPL for NASA. The VIMS team is based at the University of Arizona in Tucson.


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


2013-297
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Asteroid 2013 TV135 - A Reality Check

Asteroid 2013 TV135 - A Reality Check:

Diagram showing orbit of asteroid 2013 TV135
This diagram shows the orbit of asteroid 2013 TV135 (in blue), which has just a one-in-63,000 chance of impacting Earth. Its risk to Earth will likely be further downgraded as scientists continue their investigations. Image credit: NASA/JPL-Caltech

› Larger image

October 17, 2013

Newly discovered asteroid 2013 TV135 made a close approach to Earth on Sept. 16, when it came within about 4.2 million miles (6.7 million kilometers). The asteroid is initially estimated to be about 1,300 feet (400 meters) in size and its orbit carries it as far out as about three quarters of the distance to Jupiter's orbit and as close to the sun as Earth's orbit. It was discovered on Oct. 8, 2013, by astronomers working at the Crimean Astrophysical Observatory in Ukraine. As of Oct. 14, asteroid 2013 TV135 is one of 10,332 near-Earth objects that have been discovered.


With only a week of observations for an orbital period that spans almost four years, its future orbital path is still quite uncertain, but this asteroid could be back in Earth's neighborhood in 2032. However, NASA's Near-Earth Object Program Office states the probability this asteroid could then impact Earth is only one in 63,000. The object should be easily observable in the coming months and once additional observations are provided to the Minor Planet Center in Cambridge, Mass., the initial orbit calculations will be improved and the most likely result will be a dramatic reduction, or complete elimination, of any risk of Earth impact.


"To put it another way, that puts the current probability of no impact in 2032 at about 99.998 percent," said Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "This is a relatively new discovery. With more observations, I fully expect we will be able to significantly reduce, or rule out entirely, any impact probability for the foreseeable future."


NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and identifies their orbits to determine if any could be potentially hazardous to our planet.


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 at: http://www.jpl.nasa.gov/asteroidwatch.

DC Agle 818-393-9011

Jet Propulsion Laboratory, Pasadena, Calif.

agle@jpl.nasa.gov

2013-300
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Long-Sought Pattern of Ancient Light Detected

Long-Sought Pattern of Ancient Light Detected:

Artist's impression shows how photons from the early universe are deflected by the gravitational lensing effect of massive cosmic structures as they travel across the universe
This artist's impression shows how photons from the early universe are deflected by the gravitational lensing effect of massive cosmic structures as they travel across the universe. Image credit: ESA

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October 21, 2013

The journey of light from the very early universe to modern telescopes is long and winding. The ancient light traveled billions of years to reach us, and along the way, its path was distorted by the pull of matter, leading to a twisted light pattern.


This twisted pattern of light, called B-modes, has at last been detected. The discovery, which will lead to better maps of matter across our universe, was made using the National Science Foundation's South Pole Telescope, with help from the Herschel space observatory.


Scientists have long predicted two types of B-modes: the ones that were recently found were generated a few billion years into our universe's existence (it is presently 13.8 billion years old). The others, called primordial, are theorized to have been produced when the universe was a newborn baby, fractions of a second after its birth in the Big Bang.


"This latest discovery is a good checkpoint on our way to the measurement of primordial B-modes," said Duncan Hanson of McGill University in Montreal, Canada, lead author of the new report published Sept. 30 in the online edition of Physical Review Letters.


The elusive primordial B-modes may be imprinted with clues about how our universe was born. Scientists are currently combing through data from the Planck mission in search of them. Both Herschel and Planck are European Space Agency missions, with important NASA contributions.


The oldest light we see around us today, called the cosmic microwave background, harkens back to a time just hundreds of millions of years after the universe was created. Planck recently produced the best-ever full-sky map of this light, revealing new details about of our cosmos' age, contents and origins. A fraction of this ancient light is polarized, a process that causes light waves to vibrate in the same plane. The same phenomenon occurs when sunlight reflects off lakes, or particles in our atmosphere. On Earth, special sunglasses can isolate this polarized light, reducing glare.


The B-modes are a twisted pattern of polarized light. In the new study, the scientists were on a hunt for the kind of polarized light spawned by matter in a process called gravitational lensing, where the gravitational pull from knots of matter distorts the path of light.


The signals are extremely faint, so Hanson and colleagues used Herschel's infrared map of matter to get a better idea of where to look. The researchers then spotted the signals with the South Pole Telescope, making the first-ever detection of B-modes. This is an important step for better mapping how matter, both normal and dark, is distributed throughout our universe. Clumps of matter in the early universe are the seeds of galaxies like our Milky Way.


Astronomers are eager to detect primordial B-modes next. These polarization signals, from billions of years ago, would be much brighter on larger scales, which an all-sky mission like Planck is better able to see.


"These beautiful measurements from the South Pole Telescope and Herschel strengthen our confidence in our current model of the universe," said Olivier Doré, a member of the U.S. Planck science team at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "However, this model does not tell us how big the primordial signal itself should be. We are thus really exploring with excitement a new territory here, and a potentially very, very old one."


Read the European Space Agency feature about this work at http://www.esa.int/Our_Activities/Space_Science/Herschel/Herschel_helps_find_elusive_signals_from_the_early_Universe.


Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.


More information is online at http://www.herschel.caltech.edu, http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel.


Planck is a European Space Agency mission, with significant participation from NASA. NASA's Planck Project Office is based at JPL. JPL contributed mission-enabling technology for both of Planck's science instruments. European, Canadian and U.S. Planck scientists work together to analyze the Planck data. More information is online at http://www.nasa.gov/planck and http://www.esa.int/planck.

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov

2013-301
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Last Command Sent to Planck Space Telescope

Last Command Sent to Planck Space Telescope:

An artist's concept of Planck
The oldest light in the universe, called the cosmic microwave background, as observed by the Planck space telescope is shown in the oval sky map. An artist's concept of Planck is next to the map. Image credit: ESA and the Planck Collaboration - D. Ducros

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October 23, 2013

The Planck space telescope has been turned off after spending nearly 4.5 years soaking up the relic radiation from the Big Bang and studying the evolution of stars and galaxies throughout the history of the universe.


Planck is a European Space Agency (ESA) mission with significant contributions from NASA.


Mission controllers at ESA's operations center in Darmstadt, Germany sent the final command to the Planck satellite today, marking the end of operations for what some like to call a "time machine."


"We are only part way through the analysis of the data and have already learned a huge amount about the universe from the Milky Way galaxy, to the observable edge, and beyond to the first tiny fraction of a second after the Big Bang," said U.S. Planck Project Scientist Charles Lawrence of NASA's Jet Propulsion Laboratory, Pasadena, Calif.


Launched in 2009, Planck was designed to tease out the faintest relic radiation from the Big Bang, called the cosmic microwave background. This radiation preserves a picture of the universe as it was about 380,000 years after its birth, and provides details of the initial conditions that led to the universe we live in today.


Results from the mission presented by scientists in March 2013 provided revised values for the relative proportions of the ingredients of the universe, namely normal matter that makes up stars and galaxies; dark matter, which has so far only been detected indirectly by its gravitational influence; and dark energy, a mysterious force thought to be responsible for accelerating the expansion of the universe. The NASA news release about these results is at http://www.jpl.nasa.gov/news/news.php?release=2013-109 .


JPL built critical components of Planck's science instruments, including bolometers for the mission's high-frequency instrument; a 20-Kelvin (minus-424-degree-Fahrenheit) cryocooler for both the low- and high-frequency instruments; and amplifier technology for the low-frequency instrument.


But cooling instruments to these extreme temperatures cannot be maintained forever and, indeed, the High Frequency Instrument exhausted its liquid helium coolant in January 2012, just as expected.


The Low Frequency Instrument meanwhile continued to operate at somewhat higher temperatures using the remaining two coolers, and it observed the sky until Oct. 3. After conducting post-science activities, it was manually switched off Oct. 19.


"Planck is a model for international cooperation in space. Both Europe and the U.S. contributed enabling new technologies, giving Planck unprecedented scientific capability," said Ulf Israelsson, the U.S. Planck Project Manager at JPL.


Read the full ESA news release at: http://spaceinimages.esa.int/Images/2013/03/Planck_and_the_cosmic_microwave_background .


Planck is a European Space Agency mission, with significant participation from NASA. NASA's Planck Project Office is based at JPL. JPL contributed mission-enabling technology for both of Planck's science instruments. European, Canadian and U.S. Planck scientists work together to analyze the Planck data. More information is online at http://www.nasa.gov/planck, http://www.esa.int/planck and http://planck.caltech.edu .

Whitney Clavin 818-354-4673?

Jet Propulsion Laboratory, Pasadena, Calif.?

whitney.clavin@jpl.nasa.gov


2013-303
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NASA's Great Observatories Begin Deepest-Ever Probe of the Universe

NASA's Great Observatories Begin Deepest-Ever Probe of the Universe:

Galaxy clusters
These are NASA Hubble Space Telescope natural-color images of four target galaxy clusters that are part of an ambitious new observing program called The Frontier Fields.
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October 24, 2013

PASADENA, Calif. -- NASA's Hubble, Spitzer and Chandra space telescopes are teaming up to look deeper into the universe than ever before. With a boost from natural "zoom lenses" found in space, they should be able to uncover galaxies that are as much as 100 times fainter than what these three great observatories typically can see.


In an ambitious collaborative program called The Frontier Fields, astronomers will make observations during the next three years peering at six massive clusters of galaxies, exploiting a natural phenomenon known as gravitational lensing, to learn not only what is inside the clusters but also what is beyond them. The clusters are among the most massive assemblages of matter known, and their gravitational fields can be used to brighten and magnify more distant galaxies so they can be observed.


"The Frontier Fields program is exactly what NASA's Great Observatories were designed to do; working together to unravel the mysteries of the universe" said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington. "Each observatory collects images using different wavelengths of light with the result that we get a much deeper understanding of the underlying physics of these celestial objects."


The first object they will view is Abell 2744, commonly known as Pandora's Cluster. The giant galaxy cluster appears to be the result of a simultaneous pile-up of at least four separate, smaller galaxy clusters that took place over a span of 350 million years.


Astronomers anticipate these observations will reveal populations of galaxies that existed when the universe was only a few hundred million years old, but have not been seen before.


"The idea is to use nature's natural telescopes in combination with the great observatories to look much deeper than before and find the most distant and faint galaxies we can possibly see," said Jennifer Lotz, a principal investigator with the Space Telescope Science Institute in Baltimore, Md.


Data from the Hubble and Spitzer space telescopes will be combined to measure the galaxies' distances and masses more accurately than either observatory could measure alone, demonstrating their synergy for such studies.


"We want to understand when and how the first stars and galaxies formed in the universe, and each great observatory gives us a different piece of the puzzle," said Peter Capak, the Spitzer principal investigator for the Frontier Fields program at NASA's Spitzer Science Center at the California Institute of Technology, Pasadena. "Hubble tells you which galaxies to look at and how many stars are being born in those systems. Spitzer tells you how old the galaxy is and how many stars have formed."


The Chandra X-ray Observatory also will peer deep into the star fields. It will image the clusters at X-ray wavelengths to help determine their mass and measure their gravitational lensing power, and identify background galaxies hosting supermassive black holes.


High-resolution Hubble data from Frontier Fields will be used to trace the distribution of dark matter within the six massive foreground clusters. Accounting for the bulk of the universe's mass, dark matter is the underlying invisible scaffolding attached to galaxies.


Hubble and Spitzer have studied other deep fields with great success. The Frontier Fields researchers anticipate a challenge because the distortion and magnification caused by the gravitational lensing phenomenon will make it difficult for them to understand the true properties of the background galaxies.


For images and more information about The Frontier Fields, visit: http://hubblesite.org/news/2013/44 .


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 .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov

Ray Villard 410-338-4514

Space Telescope Science Institute, Baltimore, Md.

villard@stsci.edu

J.D. Harrington 202-358-5241

Headquarters, Washington

j.d.harrington@nasa.gov


2013-306
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Carbon Worlds May be Waterless, Finds NASA Study

Carbon Worlds May be Waterless, Finds NASA Study:

This artist's concept illustrates the fate of two different planets: the one on the left is similar to Earth, made up largely of silicate-based rocks with oceans coating its surface
This artist's concept illustrates the fate of two different planets: the one on the left is similar to Earth, made up largely of silicate-based rocks with oceans coating its surface. The one on the right is rich in carbon -- and dry. Chances are low that life as we know it, which requires liquid water, would thrive under such barren conditions. Image credit: NASA/JPL-Caltech
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October 25, 2013

Planets rich in carbon, including so-called diamond planets, may lack oceans, according to NASA-funded theoretical research.


Our sun is a carbon-poor star, and as result, our planet Earth is made up largely of silicates, not carbon. Stars with much more carbon than the sun, on the other hand, are predicted to make planets chock full of carbon, and perhaps even layers of diamond.


By modeling the ingredients in these carbon-based planetary systems, the scientists determined they lack icy water reservoirs thought to supply planets with oceans.


"The building blocks that went into making our oceans are the icy asteroids and comets," said Torrence Johnson of NASA's Jet Propulsion Laboratory in Pasadena, Calif, who presented the results Oct. 7 at the American Astronomical Society Division of Planetary Sciences meeting in Denver. Johnson, a team member of several NASA planetary missions, including Galileo, Voyager and Cassini, has spent decades studying the planets in our own solar system.


"If we keep track of these building blocks, we find that planets around carbon-rich stars come up dry," he said.


Johnson and his colleagues say the extra carbon in developing star systems would snag the oxygen, preventing it from forming water.


"It's ironic that if carbon, the main element of life, becomes too abundant, it will steal away the oxygen that would have made water, the solvent essential to life as we know it," said Jonathan Lunine of Cornell University, Ithaca, N.Y., a collaborator on the research.


One of the big questions in the study of planets beyond our solar system, called exoplanets, is whether or not they are habitable. Researchers identify such planets by first looking for those that are situated within the "habitable zone" around their parent stars, which is where temperatures are warm enough for water to pool on the surface. NASA's Kepler mission has found several planets within this zone, and researchers continue to scrutinize the Kepler data for candidates as small as Earth.


But even if a planet is found in this so-called "Goldilocks" zone, where oceans could, in theory, abound, is there actually enough water available to wet the surface? Johnson and his team addressed this question with planetary models based on measurements of our sun's carbon-to-oxygen ratio. Our sun, like other stars, inherited a soup of elements from the Big Bang and from previous generations of stars, including hydrogen, helium, nitrogen, silicon, carbon and oxygen.


"Our universe has its own top 10 list of elements," said Johnson, referring to the 10 most abundant elements in our universe.


These models accurately predict how much water was locked up in the form of ice early in the history of our solar system, billions of years ago, before making its way to Earth. Comets and/or the parent bodies of asteroids are thought to have been the main water suppliers, though researchers still debate their roles. Either way, the objects are said to have begun their journey from far beyond Earth, past a boundary called the "snow line," before impacting Earth and depositing water deep in the planet and on its surface.


When the researchers applied the planetary models to the carbon-rich stars, the water disappeared. "There's no snow beyond the snow line," said Johnson.


"All rocky planets aren't created equal," said Lunine. "So-called diamond planets the size of Earth, if they exist, will look totally alien to us: lifeless, ocean-less desert worlds."


The computer model results supporting these conclusions were published in the Astrophysical Journal last year (http://arxiv.org/abs/1208.3289). The implications for habitability in these systems were the focus of the Division of Planetary Sciences meeting.


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


2013-308
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Ghostly Specter Haunts the 'Coldest Place in the Universe'

Ghostly Specter Haunts the 'Coldest Place in the Universe':

The Boomerang nebula, called the
The Boomerang nebula, called the "coldest place in the universe," reveals its true shape to the Atacama Large Millimeter/submillimeter Array (ALMA) telescope. Image credit: NRAO/AUI/NSF/NASA/STScI/JPL-Caltech

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October 25, 2013

At a cosmologically crisp one degree Kelvin (minus 458 degrees Fahrenheit), the Boomerang nebula is the coldest known object in the universe -- colder, in fact, than the faint afterglow of the Big Bang, the explosive event that created the cosmos.


Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile have taken a new look at this object to learn more about its frigid properties and to determine its true shape, which has an eerily ghost-like appearance.


"This ultra-cold object is extremely intriguing and we're learning much more about its true nature with ALMA," said Raghvendra Sahai, a researcher and principal scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and lead author of a paper published in the Astrophysical Journal. "What seemed like a double lobe, or boomerang shape, from Earth-based optical telescopes, is actually a much broader structure that is expanding rapidly into space."


As originally observed with ground-based telescopes, this nebula appeared lopsided, which is how it got its name. Later observations with NASA's Hubble Space Telescope revealed a bow-tie-like structure. The new ALMA data, however, reveal that the Hubble image tells only part of the story, and the twin lobes seen in that image may actually be a trick of light as seen at visible wavelengths.


The researchers discovered a dense lane of millimeter-sized dust grains surrounding the star, which explains why its outer cloud has an hourglass shape in visible light. These minute dust grains have created a mask that shades a portion of the central star and allows its light to leak out only in narrow but opposite directions into the cloud, giving it an hourglass appearance.


"This is important for the understanding of how stars die and become planetary nebulas," said Sahai. "Using ALMA, we were quite literally, and figuratively, able to shed new light on the death throes of a sun-like star."


The Boomerang nebula, located about 5,000 light-years away in the constellation Centaurus, is a relatively young example of an object known as a planetary nebula. Planetary nebulas, contrary to their name, are actually the end-of-life phases of stars like our sun that have sloughed off their outer layers. What remains at their centers are white dwarf stars, which emit intense ultraviolet radiation that causes the gas in the nebulae to glow and emit light in brilliant colors.


Read the full ALMA release online at https://public.nrao.edu/news/pressreleases/alma-reveals-coldest-place-in-the-universe .


Additional authors on this paper include Wouter Vlemmings, Chalmers University of Technology, Onsala, Sweden; Patrick Huggins, New York University, New York; Lars-Ake Nyman, Joint ALMA Observatory, Santiago de Chile; and Yiannis Gonidakis, CSIRO, Australia Telescope National Facility.


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 European Southern Observatory, 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.


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


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

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-310
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Cassini Swings Above Saturn to Compose a Portrait

Cassini Swings Above Saturn to Compose a Portrait:

A swing high above Saturn by NASA's Cassini spacecraft revealed this stately view of the golden-hued planet and its main rings
A swing high above Saturn by NASA's Cassini spacecraft revealed this stately view of the golden-hued planet and its main rings. The view is in natural color, as human eyes would have seen it. Image credit: NASA/JPL-Caltech/SSI/Cornell

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October 25, 2013

It's a view as good as gold. A loop high above Saturn by NASA's Cassini spacecraft revealed this stately view of the golden-hued planet and its main rings. The observation and resulting image mosaic were planned as one of three images for Cassini's 2013 Scientist for a Day essay contest. The contest challenges students to study three possible targets and write about which one they think will yield the best science. Today is the last day for U.S. submissions and the Cassini mission has already started working on picking the best essays.


This natural-color view -- seen as human eyes would have seen it - was obtained on Oct. 10, 2013. It shows off the differently colored bands of weather at Saturn. A bright, wavy stream of clouds around 42 degrees north latitude appears to mark some of the turbulent aftermath of a giant storm that reached its violent peak in early 2011. The mysterious six-sided weather pattern known as the hexagon is also visible around Saturn's north pole.


When Cassini arrived in 2004, more of the northern hemisphere sported a bluish hue and it was northern winter. The golden tones dominated the southern hemisphere, where it was southern summer. But as the seasons have turned and northern summer has begun, the colors have begun to change in each hemisphere as well. Golden tones have started to dominate in the northern hemisphere and the bluish color in the north is now confined to a tighter circle around the north pole.


Cassini is currently in a special set of tilted orbits known as "inclined orbits" that allow the spacecraft to swing up over the north pole and below the south pole. Cassini was tilted as much as 62 degrees from the plane of Saturn's equator in April of this year and will continue to work its way back down again till early 2015. Much of Cassini's tour has involved orbits around the equatorial plane, where most of Saturn's rings and moons are located.


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 Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team consists of scientists from the United States, the United Kingdom, France and Germany. The imaging operations center is based at the Space Science Institute in Boulder, Colo.


For more information about Cassini and its 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

2013-311
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Watching Earth's Winds, On a Shoestring

Watching Earth's Winds, On a Shoestring:

Artist's rendering of NASA's ISS-RapidScat instrument (inset), which will launch to the International Space Station in 2014
Artist's rendering of NASA's ISS-RapidScat instrument (inset), which will launch to the International Space Station in 2014 to measure ocean surface wind speed and direction and help improve weather forecasts, including hurricane monitoring. It will be installed on the end of the station's Columbus laboratory. Credit: NASA/JPL-Caltech/Johnson Space Center.
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October 29, 2013

Built with spare parts and without a moment to spare, the International Space Station (ISS)-RapidScat isn't your average NASA Earth science mission.

Short for Rapid Scatterometer, ISS-RapidScat will monitor ocean winds from the vantage point of the space station . It will join a handful of other satellite scatterometer missions that make essential measurements used to support weather and marine forecasting, including the tracking of storms and hurricanes. It will also help improve our understanding of how interactions between Earth's ocean and atmosphere influence our climate.

Scientists study ocean winds for a variety of reasons. Winds over the ocean are an important part of weather systems, and in severe storms such as hurricanes they can inflict major damage. Ocean storms drive coastal surges, which are a significant hazard for populations. At the same time, by driving warm surface ocean water away from the coast, ocean winds cause nutrient-rich deep water to well up, providing a major source of food for coastal fisheries. Changes in ocean wind also help us monitor large-scale changes in Earth's climate, such as El Niño .

Scatterometers work by safely bouncing low-energy microwaves - the same kind used at high energy to warm up food in your kitchen - off the surface of Earth. In this case, the surface is not land, but the ocean. By measuring the strength and direction of the microwave echo, ISS-RapidScat will be able to determine how fast, and in what direction, ocean winds are blowing.

"Microwave energy emitted by a radar instrument is reflected back to the radar more strongly when the surface it illuminates is rougher," explains Ernesto Rodríguez, principal investigator for ISS-RapidScat at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "When wind blows over water, it causes waves to develop along the direction of wind. The stronger the wind, the larger the waves."

ISS-RapidScat continues a legacy of measuring ocean winds from space that began in 1978 with the launch of NASA's SeaSat satellite. Most recently, NASA's QuikScat scatterometer, which launched in 1999, gave us a dynamic picture of the world's ocean winds.

But when QuikScat lost its ability to produce ocean wind measurements in 2009, science suffered from the loss of the data. In the summer of 2012, an opportunity arose to fly a scatterometer instrument on the space station. ISS-RapidScat was the result .

Most scatterometer-carrying satellites fly in what's called a sun-synchronous orbit around Earth. In other words, they cross Earth's equator at the same local time every orbit. The space station, however, will carry the ISS-RapidScat in a non-sun-synchronous orbit. This means the instrument will see different parts of the planet at different times of day, making measurements in the same spot within less than an hour before or after another instrument makes its own observations. These all-hour measurements will allow ISS-RapidScat to pick up the effects of the sun on ocean winds as the day progresses. In addition, the space station's coverage over the tropics means that ISS-RapidScat will offer extra tracking of storms that may develop into hurricanes or other tropical cyclones.

Anywhere the wind blows

"We'll be able to see how wind speed changes with the time of day," said Rodríguez. "ISS-RapidScat will link together all previous and current scatterometer missions, providing us with a more complete picture of how ocean winds change. Combined with data from the European ASCAT scatterometer mission, we'll be able to observe 90 percent of Earth's surface at least once a day, and in many places, several times a day."

ISS-RapidScat's near-global coverage of Earth's ocean -- within the space station's orbit inclination of 51.6 degrees north and south of the equator -- will make it an important tool for scientists who observe and predict Earth's weather. "Frequent observations of the winds over the ocean are used by meteorologists to improve weather and hurricane forecasts and by the operational weather communities to improve numerical weather models," said Rodríguez.

Space-based scatterometer instruments have been built before, but much of what makes ISS-RapidScat unusual is how it came to be. "Space Station Program Manager Michael Suffredini offered us a mounting location on the space station and a free ride on a SpaceX Dragon cargo resupply mission launching in early 2014," explained Howard Eisen, the ISS-RapidScat project manager at JPL. "So we had about 18 months to put together an entire mission."

This accelerated timeline is a blink of an eye at NASA, where the typical project is years or decades in the making.

Free ride

Next, Eisen and his team turned to getting creative and crafty with the mission's hardware. In lieu of using newly-designed instruments, which would be expensive and take too long to develop, ISS-RapidScat reuses leftover hardware originally built to test parts of the QuikScat mission. That process involved dusting off and testing pieces of equipment that hadn't seen the light of day since the 1990s. Fortunately the old hardware seems ship-shape and ready to go. "Even though they were spares, they've done an excellent job so far," said Simon Collins, ISS-RapidScat's instrument manager at JPL. Despite their age, the old parts are more than capable of collecting the ocean wind data that ISS-RapidScat need to be a success.

In addition to old spare parts, some new hardware was needed to interface this instrument to the space station and the Dragon spacecraft. ISS-RapidScat will use off-the-shelf, commercially-available computer hardware instead of the expensive, hardened-against-radiation computer chips that are typically used in space missions. "If there's an error or something because of radiation, all we have to do is reset the computer. It's what we call a managed risk," said Eisen. The radiation environment on the space station is much less severe than that experienced en route to Mars, for example, or in more traditional sun-synchronous orbits.

Science bounty

Cost-saving decisions like this are shaping up to make ISS-RapidScat an exceptional bargain of a space mission. "We're doing things differently, and we're trying to do them quickly and cheaply," said Eisen. Considering that the typical launch alone can cost $200 million, ISS-RapidScat's estimated $26 million price tag seems like a bargain. Last year, NASA estimated the cost of a new, free-flying scatterometer satellite mission at approximately $400 million.

The real challenges of getting ISS-RapidScat into space lie in the details. One of the major headaches of such a hurried schedule has been getting the special connectors that will allow ISS-RapidScat to physically attach to the International Space Station. "They're special robotically-mated connectors that haven't been made in years," Eisen said. "We're having to convince the company that produces these connectors to make us a small run in time for the mission, and it hasn't been easy."

The logistics of operating an instrument on the space station are also tricky. "Typically, spacecraft are designed for the instruments they carry," said Collins. "In this case, it's the other way around." For example, ISS-RapidScat's docking point on the space station faces outward toward space - not down toward Earth and the ocean that the instrument is looking at. The space station's flying angle will also change as new pieces are added to it, in response to changes in the station's drag profile. ISS-RapidScat's mount can compensate for both of these challenges.

Another concern the ISS-RapidScat team confronted early on was that one of the space station's docking ports lies squarely within the field of view of the scatterometer. "Bombarding astronauts and visiting supply vehicles with microwave radiation from the instruments was out of the question, and turning the instrument off when there were things docked there would take away too much science," explained Collins. The project's engineers instead devised a plan where the instrument avoids irradiating docking vessels, but continues to scan across the vast majority of its viewing range.

Rodríguez is confident that the reward for overcoming such difficulties will be a bounty of vital science information. "Because it uses much of the same hardware QuikScat did, ISS-RapidScat will allow us to continue the observations of ocean winds already started," said Rodriguez. "Extending this data record will help us observe and understand weather patterns and improve our preparedness for tropical cyclones."

Joshua Rodriguez

Jet Propulsion Laboratory, Pasadena Calif.

Media contact:

Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena Calif.

Alan.buis@jpl.nasa.gov

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