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

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 PHONE 818-354-5011
http://www.jpl.nasa.gov

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

News release: 2013-287 Sept. 20, 2013

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

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-287&cid=release_2013-287

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://go.nasa.gov/19ki9LG .
For more information about Deep Impact, visit: http://www.nasa.gov/deepimpact .

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NASA Curiosity Rover Detects No Methane on Mars

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109. PHONE 818-354-5011
http://www.jpl.nasa.gov

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

News release: 2013-285 Sept. 19, 2013

NASA Curiosity Rover Detects No Methane on Mars

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-285&cid=release_2013-285

PASADENA, Calif. -- Data from NASA's Curiosity rover has revealed the Martian environment lacks methane. This is a surprise to researchers because previous data reported by U.S. and international scientists indicated positive detections.

The roving laboratory performed extensive tests to search for traces of Martian methane. Whether the Martian atmosphere contains traces of the gas has been a question of high interest for years because methane could be a potential sign of life, although it also can be produced without biology.

"This important result will help direct our efforts to examine the possibility of life on Mars," said Michael Meyer, NASA's lead scientist for Mars exploration. "It reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don't generate methane."

Curiosity analyzed samples of the Martian atmosphere for methane six times from October 2012 through June and detected none. Given the sensitivity of the instrument used, the Tunable Laser Spectrometer, and not detecting the gas, scientists calculate the amount of methane in the Martian atmosphere today must be no more than 1.3 parts per billion. That is about one-sixth as much as some earlier estimates. Details of the findings appear in the Thursday edition of Science Express.

"It would have been exciting to find methane, but we have high confidence in our measurements, and the progress in expanding knowledge is what's really important," said the report's lead author, Chris Webster of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We measured repeatedly from Martian spring to late summer, but with no detection of methane."

Webster is the lead scientist for spectrometer, which is part of Curiosity's Sample Analysis at Mars (SAM) laboratory. It can be tuned specifically for detection of trace methane. The laboratory also can concentrate any methane to increase the gas' ability to be detected. The rover team will use this method to check for methane at concentrations well below 1 part per billion.

Methane, the most abundant hydrocarbon in our solar system, has one carbon atom bound to four hydrogen atoms in each molecule. Previous reports of localized methane concentrations up to 45 parts per billion on Mars, which sparked interest in the possibility of a biological source on Mars, were based on observations from Earth and from orbit around Mars. However, the measurements from Curiosity are not consistent with such concentrations, even if the methane had dispersed globally.

"There's no known way for methane to disappear quickly from the atmosphere," said one of the paper's co-authors, Sushil Atreya of the University of Michigan, Ann Arbor. "Methane is persistent. It would last for hundreds of years in the Martian atmosphere. Without a way to take it out of the atmosphere quicker, our measurements indicate there cannot be much methane being put into the atmosphere by any mechanism, whether biology, geology, or by ultraviolet degradation of organics delivered by the fall of meteorites or interplanetary dust particles."

The highest concentration of methane that could be present without being detected by Curiosity's measurements so far would amount to no more than 10 to 20 tons per year of methane entering the Martian atmosphere, Atreya estimated. That is about 50 million times less than the rate of methane entering Earth's atmosphere.

Curiosity landed inside Gale Crater on Mars in August 2012 and is investigating evidence about habitable environments there. JPL manages the mission and built the rover for NASA's Science Mission Directorate in Washington. The rover's Sample Analysis at Mars suite of instruments was developed at NASA's Goddard Space Flight Center in Greenbelt, Md., with instrument contributions from Goddard, JPL and the University of Paris in France.

For more information about the mission, visit http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl . To learn more about the SAM instrument, visit:
http://ssed.gsfc.nasa.gov/sam/index.html .

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Long-stressed Europa Likely Off-kilter at One Time

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 PHONE 818-354-5011
http://www.jpl.nasa.gov

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

Elizabeth Zubritsky/Nancy Neal-Jones 301-614-5438/301-286-0039
Goddard Space Flight Center, Greenbelt, Md.
elizabeth.a.zubritsky@nasa.gov/nancy.n.jones@nasa.gov

Long-stressed Europa Likely Off-kilter at One Time

News release: 2013-283 Sept. 18, 2013

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-283&cid=release_2013-283

By analyzing the distinctive cracks lining the icy face of Europa, NASA scientists found evidence that this moon of Jupiter likely spun around a tilted axis at some point.

Europa's tilt could influence calculations of how much of the moon's history is recorded in its frozen shell, how much heat is generated by tides in its ocean, and even how long the ocean has been liquid.

"One of the mysteries of Europa is why the orientations of the long, straight cracks called lineaments have changed over time. It turns out that a small tilt, or obliquity, in the spin axis, sometime in the past, can explain a lot of what we see," said Alyssa Rhoden, a postdoctoral fellow with Oak Ridge Associated Universities who is working at NASA's Goddard Space Flight Center in Greenbelt, Md. She is the lead author of a paper in the September–October issue of Icarus that describes the results.

Europa's network of crisscrossing cracks serves as a record of the stresses caused by massive tides in the moon's global ocean. These tides occur because Europa travels around Jupiter in a slightly oval-shaped orbit. When Europa comes closer to the planet, the moon gets stretched like a rubber band, with the ocean height at the long ends rising nearly 100 feet (30 meters). That's roughly as high as the 2004 tsunami in the Indian Ocean, but it happens on a body that measures only about one-quarter of Earth's diameter. When Europa moves farther from Jupiter, it relaxes back into the shape of a ball.

The moon's ice layer has to stretch and flex to accommodate these changes, but when the stresses become too great, it cracks. The puzzling part is why the cracks in Europa's icy layer point in different directions over time, even though the same side of Europa always faces Jupiter.

A leading explanation has been that Europa's frozen outer shell might rotate slightly faster than the moon orbits Jupiter. If this out-of-sync rotation does occur, the same part of the ice shell would not always face Jupiter.

Rhoden and her Goddard co-author Terry Hurford put that idea to the test using images taken by NASA's Galileo spacecraft during its nearly eight-year mission, which began in 1995. "Galileo produced many paradigm shifts in our understanding of Europa, one of which was the phenomena of out-of-sync rotation," said Claudia Alexander of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who was the project manager when the Galileo mission ended.

Rhoden and Hurford compared the pattern of cracks in a key area near Europa's equator to predictions based on three different explanations. The first set of predictions was based on the rotation of the ice shell. The second set assumed that Europa was spinning around a tilted axis, which, in turn, made the orientation of the pole change over time. This effect, called precession, looks very much like what happens when a spinning toy top has started to slow down and wobble. The third explanation was that the cracks were laid out in random directions.

The researchers got the best performance when they assumed that precession had occurred, caused by a tilt of about one degree, and combined this effect with some random cracks, said Rhoden. Out-of-sync rotation was surprisingly unsuccessful, in part because Rhoden found an oversight in the original calculations for this model.

The results are compelling enough to satisfy Richard Greenberg, the professor from the University of Arizona, Tucson, who had earlier proposed the idea of out-of sync rotation.

"By extracting new information from the Galileo data, this work refines and improves our understanding of the very unusual geology of Europa," said Greenberg, who was Rhoden's undergraduate advisor and Hurford's graduate advisor.

The existence of tilt would not rule out the out-of-sync rotation, according to Rhoden and Greenberg. But it does suggest that Europa's cracks may be much more recent than previously thought. That's because the spin pole direction may change by as much as a few degrees per day, completing one precession period over several months. On the other hand, with the leading explanation, one full rotation of the ice sheet would take roughly 250,000 years. In either case, several rotations would be needed to explain the crack patterns.

A tilt also could affect the estimates of the age of Europa's ocean. Tidal forces are thought to generate the heat that keeps Europa's ocean liquid, and a tilt in the spin axis might suggest that more heat is generated by tidal forces. This heat might keep the ocean liquid longer.

The analysis does not specify when the tilt would have occurred. So far, measurements have not been made of the tilt of Europa's axis, and this is one goal scientists have for any future Europa mission.

"One of the fascinating open questions is how active Europa still is. If researchers pin down Europa's current spin axis, then our findings would allow us to assess whether the clues we are finding on the moon's surface are consistent with the present-day conditions," said Rhoden.

The Galileo mission was managed by NASA's Jet Propulsion Laboratory in Pasadena, Calif., for the agency's Science Mission Directorate. JPL is a division of the California Institute of Technology, Pasadena.

For information about NASA and agency programs, visit: http://www.nasa.gov .

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NASA Invites Social Media Fans to Earth Science Event

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 PHONE 818-354-5011
http://www.jpl.nasa.gov

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

News release: 2013-280 Sept. 16, 2013

NASA Invites Social Media Fans to Earth Science Event

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-280&cid=release_2013-280

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.

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NASA Spacecraft Embarks on Historic Journey Into Interstellar Space

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 PHONE 818-354-5011
http://www.jpl.nasa.gov

Jia-Rui C. Cook/D.C. Agle 818-354-0850/818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

Dwayne Brown 202-358-1726
Headquarters, Washington
dwayne.c.brown@nasa.gov

News release: 2013-277 Sept. 12, 2013

NASA Spacecraft Embarks on Historic Journey Into Interstellar Space

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-277&cid=release_2013-277

PASADENA, Calif. -- NASA's Voyager 1 spacecraft officially is the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from our sun.

New and unexpected data indicate Voyager 1 has been traveling for about one year through plasma, or ionized gas, present in the space between stars. Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident. A report on the analysis of this new data, an effort led by Don Gurnett and the plasma wave science team at the University of Iowa, Iowa City, is published in Thursday's edition of the journal Science.

"Now that we have new, key data, we believe this is mankind's historic leap into interstellar space," said Ed Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. "The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we've all been asking -- 'Are we there yet?' Yes, we are."

Voyager 1 first detected the increased pressure of interstellar space on the heliosphere, the bubble of charged particles surrounding the sun that reaches far beyond the outer planets, in 2004. Scientists then ramped up their search for evidence of the spacecraft's interstellar arrival, knowing the data analysis and interpretation could take months or years.

Voyager 1 does not have a working plasma sensor, so scientists needed a different way to measure the spacecraft's plasma environment to make a definitive determination of its location. A coronal mass ejection, or a massive burst of solar wind and magnetic fields, that erupted from the sun in March 2012 provided scientists the data they needed. When this unexpected gift from the sun eventually arrived at Voyager 1's location 13 months later, in April 2013, the plasma around the spacecraft began to vibrate like a violin string. On April 9, Voyager 1's plasma wave instrument detected the movement. The pitch of the oscillations helped scientists determine the density of the plasma. The particular oscillations meant the spacecraft was bathed in plasma more than 40 times denser than what they had encountered in the outer layer of the heliosphere. Density of this sort is to be expected in interstellar space.

The plasma wave science team reviewed its data and found an earlier, fainter set of oscillations in October and November 2012. Through extrapolation of measured plasma densities from both events, the team determined Voyager 1 first entered interstellar space in August 2012.

"We literally jumped out of our seats when we saw these oscillations in our data -- they showed us the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble," Gurnett said. "Clearly we had passed through the heliopause, which is the long-hypothesized boundary between the solar plasma and the interstellar plasma."

The new plasma data suggested a timeframe consistent with abrupt, durable changes in the density of energetic particles that were first detected on Aug. 25, 2012. The Voyager team generally accepts this date as the date of interstellar arrival. The charged particle and plasma changes were what would have been expected during a crossing of the heliopause.

"The team's hard work to build durable spacecraft and carefully manage the Voyager spacecraft's limited resources paid off in another first for NASA and humanity," said Suzanne Dodd, Voyager project manager, based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We expect the fields and particles science instruments on Voyager will continue to send back data through at least 2020. We can't wait to see what the Voyager instruments show us next about deep space."

Voyager 1 and its twin, Voyager 2, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn. Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft. It is about 9.5 billion miles (15 billion kilometers) away from our sun.

Voyager mission controllers still talk to or receive data from Voyager 1 and Voyager 2 every day, though the emitted signals are currently very dim, at about 23 watts -- the power of a refrigerator light bulb. By the time the signals get to Earth, they are a fraction of a billion-billionth of a watt. Data from Voyager 1's instruments are transmitted to Earth typically at 160 bits per second, and captured by 34- and 70-meter NASA Deep Space Network stations. Traveling at the speed of light, a signal from Voyager 1 takes about 17 hours to travel to Earth. After the data are transmitted to JPL and processed by the science teams, Voyager data are made publicly available.

"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and adding a new chapter in human scientific dreams and endeavors," said John Grunsfeld, NASA's associate administrator for science in Washington. "Perhaps some future deep space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their journey."

Scientists do not know when Voyager 1 will reach the undisturbed part of interstellar space where there is no influence from our sun. They also are not certain when Voyager 2 is expected to cross into interstellar space, but they believe it is not very far behind.

JPL built and operates the twin Voyager spacecraft. The Voyagers Interstellar Mission is a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of NASA's Science Mission Directorate in Washington. NASA's Deep Space Network, managed by JPL, is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions.

The cost of the Voyager 1 and Voyager 2 missions -- including launch, mission operations and the spacecraft's nuclear batteries, which were provided by the Department of Energy -- is about $988 million through September.

For a sound file of the oscillations detected by Voyager in interstellar space, animations and other information, visit: http://www.nasa.gov/voyager .

For an image of the radio signal from Voyager 1 on Feb. 21 by the National Radio Astronomy Observatory's Very Long Baseline Array, which links telescopes from Hawaii to St. Croix, visit:
http://www.nrao.edu .

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NASA News Conference Today to Discuss Voyager Spacecraft

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 PHONE 818-354-5011
http://www.jpl.nasa.gov

DC Agle/Jia-Rui Cook 818-393-9011/818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov/jccook@jpl.nasa.gov

Dwayne Brown 202-358-1726
NASA Headquarters, Washington
dwayne.c.brown@nasa.gov

News advisory: 2013-276b Sept. 12, 2013

NASA News Conference Today to Discuss Voyager Spacecraft

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-276&cid=release_2013-276

PASADENA, Calif. – NASA will host a news conference today at 11 a.m. PDT (2 p.m. EDT), to discuss NASA's Voyager mission. It is related to a paper to be published in the journal Science, which is embargoed until 11 a.m. PDT (2 p.m. EDT).

The briefing will be held at NASA Headquarters in Washington and air live on NASA Television and the agency's website.

During the news conference, the public may send questions via Twitter to #AskNASA.

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

The event will also be streamed live on Ustream at: http://www.ustream.tv/nasajpl2 .

For information about the Voyager mission, visit: http://www.nasa.gov/voyager .

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'La Nada' Climate Pattern Lingers in the Pacific

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 PHONE 818-354-5011
http://www.jpl.nasa.gov

Alan Buis 818-354-0474
Jet Propulsion Laboratory, Pasadena, Calif.
Alan.buis@jpl.nasa.gov

News feature: 2013-272 Sept. 9, 2013

'La Nada' Climate Pattern Lingers in the Pacific

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-272&cid=release_2013-272

New remote sensing data from NASA's Jason-2 satellite show near-normal sea-surface height conditions across the equatorial Pacific Ocean. This neutral, or "La Nada" event, has stubbornly persisted for 16 months, since spring 2012. Models suggest this pattern will continue through the spring of 2014, according to the National Weather Service's Climate Prediction Center.

"Without an El Niño or La Niña signal present, other, less predictable, climatic factors will govern fall, winter and spring weather conditions," said climatologist Bill Patzert of NASA's Jet Propulsion Laboratory, Pasadena, Calif. Long-range forecasts are most successful during El Niño and La Niña episodes. The "in between" ocean state, La Nada, is the dominant condition, and is frustrating for long-range forecasters. It's like driving without a decent road map -- it makes forecasting difficult."

The near-normal conditions are shown in a new image (as areas shaded in green), based on the average of 10 days of data centered on Aug. 27, 2013. The image is available at: http://www.jpl.nasa.gov/spaceimages/details.php?id=pia17454 .

For the past several decades, about half of all years have experienced La Nada conditions, compared to about 20 percent for El Niño and 30 percent for La Niña. 

Patzert noted that some of the wettest and driest winters occur during La Nada periods.
 
"Neutral infers something benign, but in fact if you look at these La Nada years when neither El Niño nor La Niña are present, they can be the most volatile and punishing. As an example, the continuing, deepening drought in the American West is far from 'neutral,'" he said.
 
The height of the sea water relates, in part, to its temperature, and thus is an indicator of the amount of heat stored in the ocean below. As the ocean warms, its level rises; as it cools, its level falls. Yellow and red areas indicate where the waters are relatively warmer and have expanded above normal sea level, while green (which dominates in this image) indicates near-normal sea level, and blue and purple areas show where the waters are relatively colder and sea level is lower than normal. Above-normal height variations along the equatorial Pacific indicate El Niño conditions, while below-normal height variations indicate La Niña conditions.The temperature of the upper ocean can have a significant influence on weather patterns and climate. For a more detailed explanation of what this type of image means, visit: http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/.

This latest image highlights the processes that occur on time scales of more than a year, but usually less than 10 years, such as El Niño and La Niña. These processes are known as the interannual ocean signal. To show that signal, scientists refined data for this image by removing trends over the past 20 years, seasonal variations and time-averaged signals of large-scale ocean circulation.

NASA scientists will continue to monitor this persistent La Nada event to see what the Pacific Ocean has in store next for the world's climate.
The comings and goings of El Niño, La Niña and La Nada are part of the long-term, evolving state of global climate, for which measurements of sea surface height are a key indicator. Jason-2 is a joint effort between NASA, the National Oceanic and Atmospheric Administration (NOAA), the French Space Agency Centre National d'Etudes Spatiales (CNES) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). JPL manages the U.S. portion of Jason-2 for NASA's Science Mission Directorate, Washington, D.C.

In early 2015, NASA and its international partners CNES, NOAA and EUMETSAT will launch Jason-3, which will extend the timeline of ocean surface topography measurements begun by the Topex/Poseidon and Jason 1 and 2 satellites. Jason-3 will make highly detailed measurements of sea level on Earth to gain insight into ocean circulation and climate change.

For more on NASA's satellite altimetry programs, visit: http://sealevel.jpl.nasa.gov.

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Coldest Brown Dwarfs Blur Star, Planet Lines

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Whitney Clavin 818-354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
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News release: 2013-271 Sept. 5, 2013

Coldest Brown Dwarfs Blur Star, Planet Lines

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-271&cid=release_2013-271

In 2011, astronomers on the hunt for the coldest star-like celestial bodies discovered a new class of such objects using NASA's Wide-Field Infrared Survey Explorer (WISE) space telescope. But until now, no one knew exactly how cool the bodies' surfaces really are. In fact, some evidence suggested they could be at room temperature.

A new study using data from NASA's Spitzer Space Telescope shows that while these so-called brown dwarfs are indeed the coldest known free-floating celestial bodies, they are warmer than previously thought, with surface temperatures ranging from about 250 to 350 degrees Fahrenheit (125 to 175 degrees Celsius). By comparison, the sun has a surface temperature of about 10,340 degrees Fahrenheit (5,730 degrees Celsius).

To reach these surface temperatures after cooling for billions of years, these objects would have to have masses of only five to 20 times that of Jupiter. Unlike the sun, the only source of energy for these coldest of brown dwarfs is from their gravitational contraction, which depends directly on their mass. The sun is powered by the conversion of hydrogen to helium; these brown dwarfs are not hot enough for this type of "nuclear burning" to occur.

The findings help researchers understand how planets and stars form.

"If one of these objects were found orbiting a star, there is a good chance that it would be called a planet," said Trent Dupuy, a Hubble Fellow at the Harvard-Smithsonian Center for Astrophysics and a co-author of the study, appearing online Sept. 5 in the journal Science Express. But because they probably formed on their own and not in a planet-forming disk orbiting a more massive star, astronomers still call these objects brown dwarfs even if their mass is of planetary size.

Characterizing these cold brown dwarfs is challenging because they emit most of their light at infrared wavelengths and are very faint due to their small size and low temperature.

To get accurate temperatures, astronomers need to know the distances to these objects. "We wanted to find out if they were colder, fainter and nearby, or if they were warmer, brighter and more distant," explains Dupuy.

Using Spitzer, the team determined that the brown dwarfs in question are located at distances 20 to 50 light-years away.

To determine the distances to these objects, the team measured their parallax -- the apparent change in position against background stars over time. As Spitzer orbits the sun, its perspective changes and nearby objects appear to shift back and forth slightly. The same effect occurs if you hold up a finger in front of your face and close one eye and then the other. The position of your finger seems to shift when viewed against the distant background.

But even for these relatively nearby brown dwarfs, the parallax motion is small. "To be able to determine accurate distances, our measurements had to be the same precision as knowing the position of a firefly to within 1 inch (2.5 centimeters) from 200 miles (320 kilometers) away," explained Adam Kraus, professor at the University of Texas at Austin and the study's other co-author.

The new data also present new puzzles to astronomers who study cool, planet-like atmospheres. Unlike warmer brown dwarfs and stars, the observable properties of these objects don't seem to correlate as strongly with temperature. This suggests increased roles for other factors, such as convective mixing, in driving the chemistry at the surface.

This study examined the initial sample of the coldest brown dwarfs discovered in the WISE survey data. Additional objects discovered in the past two years remain to be studied, and scientists hope they will shed light on some of these outstanding issues.

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. 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.

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NASA Evaluates Four Candidate Sites for 2016 Mars Mission

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Jet Propulsion Laboratory, Pasadena, Calif.
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Dwayne Brown 202-358-1726
NASA Headquarters, Washington
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News release: 2013-269 Sept. 4, 2013

NASA Evaluates Four Candidate Sites for 2016 Mars Mission

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-269&cid=release_2013-269

NASA has narrowed to four the number of potential landing sites for the agency's next mission to the surface of Mars, a 2016 lander to study the planet's interior.

The stationary Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport (InSight) lander is scheduled to launch in March 2016 and land on Mars six months later. It will touch down at one of four sites selected in August from a field of 22 candidates. All four semi-finalist spots lie near each other on an equatorial plain in an area of Mars called Elysium Planitia.

"We picked four sites that look safest," said geologist Matt Golombek of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Golombek is leading the site-selection process for InSight. "They have mostly smooth terrain, few rocks and very little slope."

Scientists will focus two of NASA's Mars Reconnaissance Orbiter cameras on the semi-finalists in the coming months to gain data they will use to select the best of the four sites well before InSight is launched.

The mission will investigate processes that formed and shaped Mars and will help scientists better understand the evolution of our inner solar system's rocky planets, including Earth. Unlike previous Mars landings, what is on the surface in the area matters little in the choice of a site except for safety considerations.

"This mission's science goals are not related to any specific location on Mars because we're studying the planet as a whole, down to its core," said Bruce Banerdt, InSight principal investigator at JPL. "Mission safety and survival are what drive our criteria for a landing site."

Each semifinalist site is an ellipse measuring 81 miles (130 kilometers) from east to west and 17 miles (27 kilometers) from north to south. Engineers calculate the spacecraft will have a 99-percent chance of landing within that ellipse, if targeted for the center.

Elysium is one of three areas on Mars that meet two basic engineering constraints for InSight. One requirement is being close enough to the equator for the lander's solar array to have adequate power at all times of the year. Also, the elevation must be low enough to have sufficient atmosphere above the site for a safe landing. The spacecraft will use the atmosphere for deceleration during descent.

All four semifinalist sites, as well as the rest of the 22 candidate sites studied, are in Elysium Planitia. The only other two areas of Mars meeting the requirements of being near the equator at low elevation, Isidis Planitia and Valles Marineris, are too rocky and windy. Valles Marineris also lacks any swath of flat ground large enough for a safe landing.

InSight also needs penetrable ground, so it can deploy a heat-flow probe that will hammer itself 3 yards to 5 yards into the surface to monitor heat coming from the planet's interior. This tool can penetrate through broken-up surface material or soil, but could be foiled by solid bedrock or large rocks.

"For this mission, we needed to look below the surface to evaluate candidate landing sites," Golombek said.

InSight's heat probe must penetrate the ground to the needed depth, so scientists studied Mars Reconnaissance Orbiter images of large rocks near Martian craters formed by asteroid impacts. Impacts excavate rocks from the subsurface, so by looking in the area surrounding craters, the scientists could tell if the subsurface would have probe-blocking rocks lurking beneath the soil surface.

InSight also will deploy a seismometer on the surface and will use its radio for scientific measurements.

JPL manages InSight for NASA's Science Mission Directorate in Washington. The French space agency, Centre National d'Etudes Spatiales, and the German Aerospace Center are contributing instruments to the mission. Lockheed Martin Space Systems, Denver, is building the spacecraft.

InSight is part of NASA's Discovery Program, which NASA's Marshall Space Flight Center in Huntsville, Ala., manages. InSight's team includes U.S. and international co-investigators from universities, industry and government agencies.

For more information about InSight, visit: http://insight.jpl.nasa.gov . Additional information on the Discovery Program is available at: http://discovery.nasa.gov .

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Cassini Sees Saturn Storm's Explosive Power

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Jia-Rui C. Cook 818-354-0850
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Terry Devitt 608-262-8282
University of Wisconsin, Madison
trdevitt@wisc.edu

News feature: 2013-268              Sept. 3, 2013

Cassini Sees Saturn Storm's Explosive Power

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-268&cid=release_2013-268

A monster storm that erupted on Saturn in late 2010 – as large as any storm ever observed on the ringed planet -- has already impressed researchers with its intensity and long-lived turbulence. A new paper in the journal Icarus reveals another facet of the storm's explosive power: its ability to churn up water ice from great depths. This finding, derived from near-infrared measurements by NASA's Cassini spacecraft, is the first detection at Saturn of water ice. The water originates from deep in Saturn's atmosphere.

"The new finding from Cassini shows that Saturn can dredge up material from more than 100 miles [160 kilometers]," said Kevin Baines, a co-author of the paper who works at the University of Wisconsin-Madison and NASA's Jet Propulsion Laboratory, Pasadena, Calif. "It demonstrates in a very real sense that typically demure-looking Saturn can be just as explosive or even more so than typically stormy Jupiter." Water ice, which originates from deep in the atmosphere of gas giants, doesn't appear to be lofted as high at Jupiter.

Monster storms rip across the northern hemisphere of Saturn once every 30 years or so, or roughly once per Saturn year. The first hint of the most recent storm first appeared in data from Cassini's radio and plasma wave subsystem on Dec. 5, 2010. Soon after that, it could be seen in images from amateur astronomers and from Cassini's imaging science subsystem. The storm quickly grew to superstorm proportions, encircling the planet at about 30 degrees north latitude for an expanse of nearly 190,000 miles (300,000 kilometers).

The new paper focuses on data gathered by Cassini's visual and infrared mapping spectrometer on Feb. 24, 2011. The team, led by Lawrence Sromovsky, also of the University of Wisconsin, found that cloud particles at the top of the great storm are composed of a mix of three substances: water ice, ammonia ice, and an uncertain third constituent that is possibly ammonium hydrosulfide. The observations are consistent with clouds of different chemical compositions existing side-by-side, though it is more likely that the individual cloud particles are composed of two or all three of the materials.

The classic model of Saturn's atmosphere portrays it as a layered sandwich of sorts, with a deck of water clouds at the bottom, ammonia hydrosulfide clouds in the middle, and ammonia clouds near the top. Those layers are just below an upper tropospheric haze of unknown composition that obscures almost everything.

But this storm appears to have disrupted those neat layers, lofting up water vapor from a lower layer that condensed and froze as it rose. The water ice crystals then appeared to become coated with more volatile materials like ammonium hydrosulfide and ammonia as the temperature decreased with their ascent, the authors said.

"We think this huge thunderstorm is driving these cloud particles upward, sort of like a volcano bringing up material from the depths and making it visible from outside the atmosphere," said Sromovsky. "The upper haze is so optically thick that it is only in the stormy regions where the haze is penetrated by powerful updrafts that you can see evidence for the ammonia ice and the water ice. Those storm particles have an infrared color signature that is very different from the haze particles in the surrounding atmosphere."

In understanding the dynamics of this Saturn storm, researchers realized that it worked like the much smaller convective storms on Earth, where air and water vapor are pushed high into the atmosphere, resulting in the towering, billowing clouds of a thunderstorm. The towering clouds in Saturn storms of this type, however, were 10 to 20 times taller and covered a much bigger area. They are also far more violent than an Earth storm, with models predicting vertical winds of more than about 300 mph (500 kilometers per hour) for these rare giant storms.

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 .

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NASA Study Eyes Soot's Role in 1800s Glacier Retreat

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Alan Buis 818-354-0474
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NASA Headquarters, Washington
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News release: 2013-267 Sept. 3, 2013

NASA Study Eyes Soot's Role in 1800s Glacier Retreat

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.php?release=2013-267&cid=release_2013-267

PASADENA, Calif. – A NASA-led team of scientists has uncovered strong evidence that soot from a rapidly industrializing Europe caused the abrupt retreat of mountain glaciers in the European Alps that began in the 1860s, a period often thought of as the end of the Little Ice Age.

The research, published Sept. 3 in the Proceedings of the National Academy of Sciences, may help resolve a longstanding scientific debate.

In the decades following the 1850s, Europe underwent an economic and atmospheric transformation spurred by industrialization. The use of coal to heat homes and power transportation and industry in Western Europe began in earnest, spewing huge quantities of black carbon and other dark particles into the atmosphere.

Black carbon is the strongest sunlight-absorbing atmospheric particle. When these particles settle on the snow blanketing glaciers, they darken the snow surface, speeding its melting and exposing the underlying glacier ice to sunlight and warmer spring and summer air earlier in the year. This diminishing of the snow cover earlier in each year causes the glacier ice to melt faster and retreat.

The Little Ice Age, loosely defined as a cooler period between the 14th and 19th centuries, was marked by an expansion of mountain glaciers and a drop in temperatures in Europe of nearly 1.8 degrees Fahrenheit (1 degree Celsius). But glacier records show that between 1860 and 1930, while temperatures continued to drop, large valley glaciers in the Alps abruptly retreated by an average of nearly 0.6 mile (1 kilometer) to lengths not seen in the previous few hundred years. Glaciologists and climatologists have struggled to reconcile this apparent conflict between climate and glacier records.

"Something was missing from the equation," said Thomas Painter, a snow and ice scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., who led the study. "Before now, most glaciologists believed the end of the Little Ice Age came in the mid-1800s when these glaciers retreated, and that the retreat was due to a natural climatic shift, distinct from the carbon dioxide-induced warming that came later in the 20th century. This result suggests that human influence on glaciers extends back to well before the industrial temperature increases."

To help the scientists understand what was driving the glacier retreat, Painter and his colleagues turned to history. The researchers studied data from ice cores drilled from high up on several European mountain glaciers to determine how much black carbon was in the atmosphere and snow when the Alps glaciers began to retreat. Using the levels of carbon particles trapped in the ice core layers, and taking into consideration modern observations of how pollutants are distributed in the Alps, they were able to estimate how much black carbon was deposited on glacial surfaces at lower elevations, where levels of black carbon tend to be highest.

The team then ran computer models of glacier behavior, starting with recorded weather conditions and adding the impact of the lower-elevation pollution. When this impact was included, the simulated glacier mass loss and timing finally were consistent with the historic record of glacial retreat, despite the cooling temperatures at that time.

"We must now look more closely at other regions on Earth, such as the Himalaya, to study the present-day impacts of black carbon on glaciers in these regions," said Georg Kaser, a study co-author from the University of Innsbruck, Austria, and lead author of the Working Group I Cryosphere chapter of the Intergovernmental Panel on Climate Change's upcoming Fifth Assessment Report.

"This study uncovers likely human fingerprints on our changing environment," said co-author Waleed Abdalati, director of the Cooperative Institute for Research and Environmental Sciences (CIRES) at the University of Colorado Boulder. "It's a reminder that the actions we take have far-reaching impacts on the environment in which we live."

CIRES is a joint institute of the university and the National Oceanic and Atmospheric Administration. Other institutions participating in the study include the University of Michigan - Ann Arbor and the University of California, Davis. The California Institute of Technology in Pasadena manages JPL for NASA.

For more information about NASA programs, visit: http://www.nasa.gov


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