Wednesday, December 29, 2010

Contract Marks New Generation for Deep Space Network

The Canberra Deep Space Communications Complex, located outside Canberra, Australia.
The Canberra Deep Space Communications Complex, located outside Canberra, Australia, is one of three complexes, which comprise NASA's Deep Space Network. In this image, the 70-meter (230-foot) antenna and the 34-meter (112-foot) antennas are working side-by-side. › Larger image
NASA has taken the next step toward a new generation of Deep Space Network antennas. A $40.7 million contract with General Dynamics SATCOM Technologies, San Jose, Calif., covers implementation of two additional 34-meter (112-foot) antennas at Canberra, Australia. This is part of Phase I of a plan to eventually retire the network's aging 70-meter-wide (230-foot-wide) antennas.

The Deep Space Network (DSN) consists of three communications complexes: in Goldstone, Calif.; Madrid, Spain; and Canberra, Australia. The 70-meter antennas are more than 40 years old and are showing signs of surface deterioration from constant use. Additional 34-meter antennas are being installed in Canberra in the first phase; subsequent phases will install additional 34-meter antennas in Goldstone and Madrid.

The 34-meter beam waveguide antennas are essential to keep communications flowing smoothly as NASA's fleet of spacecraft continues to expand. In addition, the waveguide design of the antennas provides easier access for maintenance and future upgrades, because sensitive electronics are housed in a below-the-ground pedestal equipment room, instead of in the center of the dish.

"As a result of several studies, it was determined that arrays of 34-meter beam waveguide antennas were the best solution to long-term continuation of DSN 70-meter capabilities," said Miguel Marina, who manages the 70-meter replacement task force at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The new antennas are critical communication resources for all current and future NASA missions."

NASA expects to complete the building of the first two 34-meter antennas in Canberra by 2016. They will be named Deep Space Stations 35 and 36. Deep Space Station 35 is due to be online in 2014, and Deep Space Station 36 is expected to follow in 2016.

In 1958, NASA established the Deep Space Network as a separately managed and operated communications facility to accommodate all deep space missions. This avoided the need for each flight project to acquire its own specialized space communications network. During the Apollo period (1967-1972), these stations supported America's missions to the moon, including the historic first manned landing. The Goldstone antenna, in particular, captured Neil Armstrong's words and sent them on to American television sets while the images came through another antenna.

The Deep Space Network is now sending commands to numerous robotic spacecraft, such as NASA's Mars Exploration Rovers, the Spitzer Space Telescope, the Saturn explorer Cassini and the two Voyager spacecraft, which are near the edge of the solar system.

JPL, a division of the California Institute of Technology in Pasadena, manages the Deep Space Network for NASA Headquarters, Washington. More information about the Deep Space Network is online at: . More information about NASA's Space Communications and Navigation program is at: .

Wednesday, December 22, 2010

Season's Greetings: NASA Views the Change of Seasons

The change of seasons is vividly displayed in four satellite images of Lake George, New York
The change of seasons is vividly displayed in four satellite images of Lake George, New York, from the Advanced Spaceborne Thermal Emission and Reflection Radiometer instrument on NASA's Terra spacecraft. › Larger image
The change of seasons on Earth has been a cause for celebration since time immemorial. Caused by the tilt of Earth's axis relative to its orbital plane around the sun, seasons have profound changes on our weather and climate. When seasons change, nature reacts differently, depending on location. Temperatures change, rain or snow falls, rivers may flood, to name just a few effects.

From space, NASA satellites record the change of seasons. Satellite images show large parts of the landscape at one time. They help scientists study regional patterns on Earth. These images also help show bigger changes that may occur over many years.

A new slide show, "The Change of Seasons: Views from Space," shows some of the ways seasonal change affects our planet, and invites you to share your own photos of seasonal change where you live: .

Monday, December 13, 2010

Students Bounce to the Top at JPL Competition

Students from Magnolia Science Academy
Students from Magnolia Science Academy, Carson, Calif., hold their first place trophy with mentor Yunis Karaca (bottom right, wearing green).
Magnolia Science Academy, Carson, Calif., led by mentor Yunis Karaca and student captain Robert Butler, picked up top honors at the annual Invention Challenge, held today, Dec. 10, at JPL. The winning device was appropriately named "Catapult. "

The event drew more than 260 students and teachers representing 16 schools from throughout Southern California. This year's challenge was to build a unique device capable of lifting an officially supplied ping-pong ball and cause the ball to touch and hold against a ceiling located 2 meters (about 6.6 feet) above ground. The winner completed this task in the fastest time.

A total of 19 student teams competed side-by-side with 15 teams that included JPL engineers. There was a tie for the winning JPL team between P.C. Chen and David Van Buren, while second place went to Richard Goldstein and third place to Bob Krylo.

The requirements this year: The devices had to be initiated by a single operation (cut a string, flick a switch, etc.), use safe energy sources, and could be no larger, prior to the start of the task than 50 centimeters (19.7 inches) high by 1.2 meters (about 3.9 feet) wide by 1.2 meters (about 3.9 feet) long. The devices had to be made from non-toxic and safe materials.

The rules change each year, but the results remain consistent: Students challenge themselves, solve problems and appreciate that math, science and engineering can be fun.

When asked for the key to their success, Yunis Karaca, the team's mentor replied, "We first brainstormed and then I let the kids use their imagination."

Monday, December 6, 2010

NASA Aids in Characterizing Super-Earth Atmosphere

Super-Earth Exposed
The planet GJ 1214b, shown here in an artist's conception with two hypothetical moons, orbits a "red dwarf" star 40 light-years from Earth. › Full image and caption
A team of astronomers, including two NASA Sagan Fellows, has made the first characterizations of a super-Earth's atmosphere, by using a ground-based telescope. A super-Earth is a planet up to three times the size of Earth and weighing up to 10 times as much. The findings, reported in the Dec. 2 issue of the journal Nature, are a significant milestone toward eventually being able to probe the atmospheres of Earth-like planets for signs of life.

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

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

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

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

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

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

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

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

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

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

More information about NASA's planet-finding missions is online at: . More information about NASA's Sagan Fellowship Program is at .

Wednesday, December 1, 2010

Spain Supplies Weather Station for Next Mars Rover

Weather Sensors from Spain on Mars Rover Curiosity
Sensors on two finger-like mini-booms extending horizontally from the mast of NASA's Mars rover Curiosity will monitor wind speed, wind direction and air temperature. › Larger image

The first instrument from Spain for a mission to Mars will provide daily weather reports from the Red Planet. Expect extremes.

Major goals for NASA's Mars Science Laboratory include assessing the modern environment in its landing area, as well as clues to environments billions of years ago. The environment station from Spain will fill a central role in studying modern conditions by measuring daily and seasonal changes.

The Rover Environmental Monitoring Station, or REMS, is one of 10 instruments in the mission's science payload. REMS uses sensors on the mast, on the deck and inside the body of the mission's car-size rover, Curiosity. Spain's Ministry of Science and Innovation and Spain's Center for Industrial Technology Development supplied the instrument. Components were installed on Curiosity in September and are being tested at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

While most of Curiosity's electronics are sheltered for some protection from the Martian environment, the team that developed and built the environmental station needed to fashion external sensors that could tolerate the temperature extremes that some of them would be monitoring.

"That was our biggest engineering challenge," said REMS Principal Investigator Javier Gómez-Elvira, an aeronautical engineer with the Centro de Astrobiología, Madrid, Spain. "The sensors will get very cold and go through great changes in temperature every day." The Center for Astrobiology is affiliated with the Spanish National Research Council and the National Institute for Aerospace Technology.

The air temperature around the rover mast will likely drop to about minus 130 degrees Celsius (about minus 202 degrees Fahrenheit) some winter nights and climb to about minus 50 C (about minus 60 F) by 12 hours later. On warmer days, afternoon air temperatures could reach a balmy 10 to 30 C (50 to 86 F), depending on which landing site is selected.

Other challenges have included accounting for how the rover itself perturbs air movement, and keeping the entire weather station's mass to just 1.3 kilograms (2.9 pounds).

The instrument will record wind speed, wind direction, air pressure, relative humidity, air temperature and ground temperature, plus one variable that has not been measured by any previous weather station on the surface of Mars: ultraviolet radiation. Operational plans call for taking measurements for five minutes every hour of the 23-month-long mission. Twenty-three months is equal to approximately one Martian year.

Monitoring ground temperature and ultraviolet radiation along with other weather data will contribute to understanding the Martian climate and will aid the mission's assessment of whether the current environment around the rover has conditions favorable for microbial life.

"It is important to know the temperature and humidity right at ground level," said Gómez-Elvira. Humidity at the landing sites will be extremely low, but knowing daily humidity cycles at ground level could help researchers understand the interaction of water vapor between the soil and the atmosphere. If the environment supports, or ever supported, any underground microbes, that interaction could be key.

Ultraviolet radiation can also affect habitability. For example, germ-killing ultraviolet lamps are commonly used to help maintain sterile conditions for medical and research equipment. The ultraviolet sensor Curiosity's deck measures six different wavelength bands in the ultraviolet portion of the spectrum, including wavelengths also monitored from above by NASA's Mars Reconnaissance Orbiter.

The weather station will help extend years of synergy between missions that study Mars from orbit and missions on the surface.

"We will gain information about whether local conditions are favorable for habitability, and we will also contribute to understanding the global atmosphere of Mars," said Gómez-Elvira. "The circulation models of the Mars atmosphere are based mainly on observations by orbiters. Our measurements will provide a way to verify and improve the models."

For example, significant fractions of the Martian atmosphere freeze onto the ground as a south polar carbon-dioxide ice cap during southern winter and as a north polar carbon-dioxide ice cap in northern winter, returning to the atmosphere in each hemisphere's spring. At Curiosity's landing site far from either pole, REMS will check whether seasonal patterns of changing air pressure fit the existing models for effects of the coming and going of polar carbon-dioxide ice.

The sensor for air pressure, developed for REMS by the Finnish Meteorological Institute, uses a dust-shielded opening on Curiosity's deck. The most conspicuous components of the weather station are two fingers extending horizontally from partway up the rover's remote-sensing mast. Each of these two REMS mini-booms holds three electronic sensors for detecting air movement in three dimensions. Placement of the booms at an angle of 120 degrees from each other enables calculating the velocity of wind without worrying about the main mast blocking the wind. One mini-boom also holds the humidity sensor; the other a set of directional infrared sensors for measuring ground temperature.

To develop REMS and prepare for analyzing the data it will provide, Spain has assembled a team of about 40 researchers -- engineers and scientists. The team plans to post daily Mars weather reports online.

Monday, November 29, 2010

Astronomers Probe 'Sandbar' Between Islands of Galaxies

Diagram showing an unusual galaxy with bent jets
This diagram shows an unusual galaxy with bent jets (see inset). › Full image and caption
› See diagram

Astronomers have caught sight of an unusual galaxy that has illuminated new details about a celestial "sandbar" connecting two massive islands of galaxies. The research was conducted in part with NASA's Spitzer Space Telescope.

These "sandbars," or filaments, are known to span vast distances between galaxy clusters and form a lattice-like structure known as the cosmic web. Though immense, these filaments are difficult to see and study in detail. Two years ago, Spitzer's infrared eyes revealed that one such intergalactic filament containing star-forming galaxies ran between the galaxy clusters called Abell 1763 and Abell 1770.

Now these observations have been bolstered by the discovery, inside this same filament, of a galaxy that has a rare boomerang shape and unusual light emissions. Hot gas is sweeping the wandering galaxy into this shape as it passes through the filament, presenting a new way to gauge the filament's particle density. Researchers hope that other such galaxies with oddly curved profiles could serve as signposts for the faint threads, which in turn signify regions ripe for forming stars.

"These filaments are integral to the evolution of galaxy clusters -- among the biggest gravitationally bound objects in the universe -- as well as the creation of new generations of stars," said Louise Edwards, a postdoctoral researcher at the California Institute of Technology in Pasadena, and lead author of a study detailing the findings in the Dec. 1 issue of the Astrophysical Journal Letters. Her collaborators are Dario Fadda, also at Caltech, and Dave Frayer from the National Science Foundation's National Radio Astronomy Observatory, based in Charlottesville, Virginia.

Blowing in the cosmic breeze

Astronomers spotted the bent galaxy about 11 million light-years away from the center of the galaxy cluster Abell 1763 during follow-up observations with the WIYN Observatory near Tucson, Ariz., and radio-wave observations by the Very Large Array near Socorro, N.M. The WIYN Observatory is named after the consortium that owns and operates it, which includes the University of Wisconsin, Indiana University, Yale University, and the National Optical Astronomy Observatories.

The galaxy has an unusual ratio of radio to infrared light, as measured by the Very Large Array and Spitzer, making it stand out like a beacon. This is due in part to the galaxy having twin jets of material spewing in opposite directions from a supermassive black hole at its center. These jets have puffed out into giant lobes of material that emit a tremendous amount of radio waves.

Edwards and her colleagues noticed that these lobes appear to be bent back and away from the galaxy's trajectory through the filament. This bow shape, the astronomers reasoned, is due to particles in the filament pushing on the gas and dust in the lobes.

By measuring the angle of the arced lobes, Edwards' team calculated the pressure exerted by the filaments' particles and then determined the density of the medium. The method is somewhat like looking at streamers on a kite soaring overhead to judge the wind strength and the thickness of the air.

According to the data, the density inside this filament is indeed about 100 times the average density of the universe. This value agrees with that obtained in a previous X-ray study of filaments and also nicely matches predictions of supercomputer simulations.

Interconnected superclusters

Galaxies tend to bunch together as great islands in the void of space, called galaxy clusters. These galaxy groupings themselves often keep company with other clusters in "superclusters" that loom as gargantuan, gravitationally associated walls of galaxies. These structures evolved from denser patches of material as the universe rapidly expanded after the Big Bang, some 13.7 billion years ago.

The clumps and threads of this primordial matter eventually cooled, and some of it has condensed into the galaxies we see today. The leftover gas is strewn in filaments between galaxy clusters. Much of it is still quite hot -- about one million degrees Celsius (1.8 million degrees Fahrenheit) -- and blazes in high-energy X-rays that permeate galaxy clusters. Filaments are therefore best detected in X-ray light, and one direct density reading of the strands has previously been obtained in this band of frequencies.

But the X-ray-emitting gas in filaments is much more diffuse and weak than in clusters, just as submerged sandbars are extremely hard to spot at sea compared to islands poking above the water. Therefore, obtaining quality observations of filaments is time-consuming with current space observatories.

The technique by Edwards and her colleagues, which uses radio frequencies that can reach a host of ground-based telescopes, points to an easier way to probe the interiors of galaxy-cluster filaments. Instead of laboring to find subtle X-rays clues, astronomers could trust these arced "lighthouse" galaxies to indicate just where cosmic filaments lie.

Knowing how much material these filaments contain and how they interact with galaxy clusters will be very important for understanding the overall evolution of the universe, Edwards said.

The Spitzer observations were made before it ran out of its liquid coolant in May 2009 and began its warm mission.

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, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit and

Monday, November 22, 2010

NASA Funds High School Student Robotics Program

Images from the FIRST Robotics competition
NASA funds a nationwide high school robotics competition that provides students the opportunity to engage with engineers and technology experts for hands-on, realistic exposure to engineering and technical professions.

NASA is providing up to $20 million over the next five years to support a national program to inspire student interest in science, technology and mathematics with a focus on robotic technology.

The funding is part of a cooperative agreement with the Foundation for Inspiration and Recognition of Science and Technology (FIRST), a nonprofit organization in Manchester, N.H. FIRST provides students the opportunity to engage with government, industry and university experts, including those at NASA's Jet Propulsion Laboratory, Pasadena, Calif., for hands-on, realistic exposure to engineering and technical professions.

"This is the largest NASA-funded student program geared toward robotics activities," said NASA Administrator Charles Bolden. "For the next five years, approximately 25,000 students across the country will not only learn from our nation's best and brightest, but also compete and have fun at the same time."

› Read the full story

View my last 3 blog postings...

Friday, November 12, 2010

Saturn Then and Now: 30 Years Since Voyager Visit

Ed Stone, project scientist for NASA's Voyager mission, remembers the first time he saw the kinks in one of Saturn's narrowest rings. It was the day the Voyager 1 spacecraft made its closest approach to the giant ringed planet, 30 years ago. Scientists were gathering in front of television monitors and in one another's offices every day during this heady period to pore over the bewildering images and other data streaming down to NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Stone drew a crude sketch of this scalloped, multi-stranded ring, known as the F ring, in his notebook, but with no explanation next to it. The innumerable particles comprising the broad rings are in near-circular orbits about Saturn. So, it was a surprise to find that the F ring, discovered just a year before by NASA's Pioneer 11 spacecraft, had clumps and wayward kinks. What could have created such a pattern?

"It was clear Voyager was showing us something different at Saturn," said Stone, now based at the California Institute of Technology in Pasadena. "Over and over, the spacecraft revealed so many unexpected things that it often took days, months and even years to figure them out."

The F ring curiosity was only one of many strange phenomena discovered in the Voyager close encounters with Saturn, which occurred on Nov. 12, 1980, for Voyager 1, and Aug. 25, 1981, for Voyager 2. The Voyager encounters were responsible for finding six small moons and revealing the half-young, half-old terrain of Enceladus that had to point to some kind of geological activity.

Images from the two encounters also exposed individual storms roiling the planet's atmosphere, which did not show up at all in data from Earth-based telescopes. Scientists used Voyager data to resolve a debate about whether Titan had a thick or thin atmosphere, finding that Titan was shrouded in a thick haze of hydrocarbons in a nitrogen-rich atmosphere. The finding led scientists to predict there could be seas of liquid methane and ethane on Titan's surface.

"When I look back, I realize how little we actually knew about the solar system before Voyager," Stone added. "We discovered things we didn't know were there to be discovered, time after time."

In fact, the Voyager encounters sparked so many new questions that another spacecraft, NASA's Cassini, was sent to probe those mysteries. While Voyager 1 got to within about 126,000 kilometers (78,300 miles) above Saturn's cloud tops, and Voyager 2 approached as close as about 100,800 kilometers (62,600 miles), Cassini has dipped to this altitude and somewhat lower in its orbits around Saturn since 2004.

Because of Cassini's extended journey around Saturn, scientists have found explanations for many of the mysteries first seen by Voyager. Cassini has uncovered a mechanism to explain the new terrain on Enceladus – tiger stripe fissures with jets of water vapor and organic particles. It revealed that Titan indeed does have stable lakes of liquid hydrocarbons on its surface and showed just how similar to Earth that moon really is. Data from Cassini have also resolved how two small moons discovered by Voyager – Prometheus and Pandora – tug on the F ring to create its kinked shape and wakes that form snowballs.

"Cassini is indebted to Voyager for its many fascinating discoveries and for paving the way for Cassini," said Linda Spilker, Cassini project scientist at JPL, who started her career working on Voyager from 1977 to 1989. "On Cassini, we still compare our data to Voyager's and proudly build on Voyager's heritage."

But Voyager left a few mysteries that Cassini has not yet solved. For instance, scientists first spotted a hexagonal weather pattern when they stitched together Voyager images of Saturn's north pole. Cassini has obtained higher-resolution pictures of the hexagon – which tells scientists it's a remarkably stable wave in one of the jet streams that remains 30 years later – but scientists are still not sure what forces maintain the hexagon.

Even more perplexing are the somewhat wedge-shaped, transient clouds of tiny particles that Voyager discovered orbiting in Saturn's B ring. Scientists dubbed them "spokes" because they looked like bicycle spokes. Cassini scientists have been searching for them since the spacecraft first arrived. As Saturn approached equinox, and the sun's light hit the rings edge-on, the spokes did reappear in the outer part of Saturn's B ring. But Cassini scientists are still testing their theories of what might be causing these odd features.

"The fact that we still have mysteries today goes to show how much we still have to learn about our solar system," said Suzanne Dodd, Voyager's project manager, based at JPL. "Today, the Voyager spacecraft continue as pioneers traveling toward the edge of our solar system. We can't wait for the Voyager spacecraft to enter interstellar space – true outer space – and make more unexpected discoveries."

Voyager 1, which was launched on Sept. 5, 1977, is currently about 17 billion kilometers (11 billion miles) away from the sun. It is the most distant spacecraft. Voyager 2, which was launched on Aug. 20, 1977, is currently about 14 billion kilometers (9 billion miles) away from the sun.

The Voyagers were built by JPL, which continues to operate both spacecraft. Caltech manages JPL for NASA. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages Cassini for NASA. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL.

More Voyager information is available at and .

More Cassini information is available at and .

Thursday, November 11, 2010

Cassini Sees Saturn on a Cosmic Dimmer Switch

false-color composite image of Saturn
This false-color composite image, constructed from data obtained by NASA's Cassini spacecraft, shows Saturn's rings and southern hemisphere. › Full image and caption

Like a cosmic lightbulb on a dimmer switch, Saturn emitted gradually less energy each year from 2005 to 2009, according to observations by NASA's Cassini spacecraft. But unlike an ordinary bulb, Saturn's southern hemisphere consistently emitted more energy than its northern one. On top of that, energy levels changed with the seasons and differed from the last time a spacecraft visited Saturn in the early 1980s. These never-before-seen trends came from a detailed analysis of long-term data from the composite infrared spectrometer (CIRS), an instrument built by NASA's Goddard Space Flight Center in Greenbelt, Md., as well as a comparison with earlier data from NASA's Voyager spacecraft. When combined with information about the energy coming to Saturn from the sun, the results could help scientists understand the nature of Saturn's internal heat source.

"The fact that Saturn actually emits more than twice the energy it absorbs from the sun has been a puzzle for many decades now," said Kevin Baines, a Cassini team scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and a co-author on a new paper about Saturn's energy output. "What generates that extra energy? This paper represents the first step in that analysis."

The research, reported this week in the Journal of Geophysical Research-Planets, was led by Liming Li of Cornell University in Ithaca, N.Y. (now at the University of Houston).

"The Cassini CIRS data are very valuable because they give us a nearly complete picture of Saturn," Li said. "This is the only single data set that provides so much information about this planet, and it's the first time that anybody has been able to study the power emitted by one of the giant planets in such detail."

The planets in our solar system lose energy in the form of heat radiation in wavelengths that are invisible to the human eye. The CIRS instrument picks up wavelengths in the thermal infrared region, far enough beyond red light where the wavelengths correspond to heat emission.

"In planetary science, we tend to think of planets as losing power evenly in all directions and at a steady rate," Li said. "Now we know Saturn is not doing that." (Power is the amount of energy emitted per unit of time.)

Instead, Saturn's flow of outgoing energy was lopsided, with its southern hemisphere giving off about one-sixth more energy than the northern one, Li explains. This effect matched Saturn's seasons: during those five Earth-years, it was summer in the southern hemisphere and winter in the northern one. (A season on Saturn lasts about seven Earth-years.) Like Earth, Saturn has these seasons because the planet is tilted on its axis, so one hemisphere receives more energy from the sun and experiences summer, while the other receives less energy and is shrouded in winter. Saturn's equinox, when the sun was directly over the equator, occurred in August 2009.

In the study, Saturn's seasons looked Earth-like in another way: in each hemisphere, its effective temperature, which characterizes its thermal emission to space, started to warm up or cool down as a change of season approached. The effective temperature provides a simple way to track the response of Saturn's atmosphere to the seasonal changes, which is complicated because Saturn's weather is variable and the atmosphere tends to retain heat. Cassini's observations revealed that the effective temperature in the northern hemisphere gradually dropped from 2005 to 2008 and started to warm up again by 2009. In the southern hemisphere, the effective temperature cooled from 2005 to 2009.

The emitted energy for each hemisphere rose and fell along with the effective temperature. Even so, during this five-year period, the planet as a whole seemed to be slowly cooling down and emitting less energy.

To find out if similar changes were happening one Saturn-year ago, the researchers looked at data collected by the Voyager spacecraft in 1980 and 1981 and did not see the imbalance between the southern and northern hemispheres. Instead, the two regions were much more consistent with each other.

Why wouldn't Voyager have seen the same summer-versus-winter difference between the two hemispheres? One explanation is that cloud patterns at depth could have fluctuated, blocking and scattering infrared light differently.

"It's reasonable to think that the changes in Saturn's emitted power are related to cloud cover," says Amy Simon-Miller, who heads the Planetary Systems Laboratory at Goddard and is a co-author on the paper. "As the amount of cloud cover changes, the amount of radiation escaping into space also changes. This might vary during a single season and from one Saturn-year to another. But to fully understand what is happening on Saturn, we will need the other half of the picture: the amount of power being absorbed by the planet."

Scientists will be doing that as a next step by comparing the instrument's findings to data obtained by Cassini's imaging cameras and infrared mapping spectrometer instrument. The spectrometer, in particular, measures the amount of sunlight reflected by Saturn. Because scientists know the total amount of solar energy delivered to Saturn, they can derive the amount of sunlight absorbed by the planet and discern how much heat the planet itself is emitting. These calculations help scientists tackle what the actual source of that warming might be and whether it changes.

Better understanding Saturn's internal heat flow "will significantly deepen our understanding of the weather, internal structure and evolution of Saturn and the other giant planets," Li said.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency, and the Italian Space Agency. NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The composite infrared spectrometer team is based at NASA Goddard, where the instrument was built.

More Cassini information is available at and .


Wednesday, November 10, 2010

NASA Study Shows Role of Melt in Arctic Sea Ice Loss

Satellite images showing the movement of fragmented ice away from ice edges
A mosaic of satellite images shows the movement of fragmented ice away from ice edges, which scientists use to track the loss of multiyear ice due to melt. › Larger image
A NASA analysis of satellite data has quantified, for the first time, the amount of older and thicker "multiyear" sea ice lost from the Arctic Ocean due to melting.

Since the start of the satellite record in 1979, scientists have observed the continued disappearance of older "multiyear" sea ice that survives more than one summer melt season. Some scientists suspected that this loss was due entirely to wind pushing the ice out of the Arctic Basin -- a process that scientists refer to as "export." In this study, Ron Kwok and Glenn Cunningham at NASA's Jet Propulsion Laboratory in Pasadena, Calif., used a suite of satellite data to clarify the relative role of export versus melt within the Arctic Ocean.

Kwok and Cunningham show that between 1993 and 2009, a significant amount of multiyear ice -- 1,400 cubic kilometers (336 cubic miles) -- was lost due to melt, not export.

"The paper shows that there is indeed melt of old ice within the Arctic basin and the melt area has been increasing over the past several years," Kwok said. "The story is always more complicated -- there is melt as well as export -- but this is another step in calculating the mass and area balance of the Arctic ice cover."

The results have implications for understanding how Arctic sea ice gets redistributed, where melt occurs in the Arctic Ocean, and how the ocean, ice and atmosphere interact as a system to affect Earth's climate. The study was published in October 2010 in Geophysical Research Letters.

Scientists track the annual cycle of Arctic sea ice coverage as it melts through the summer to reach a minimum extent each September, before refreezing through fall and winter. Much of that ice is seasonal, meaning that it forms and melts within the year.

But multiyear ice that survives more than one season has also been declining, as noted in previous work by Joey Comiso of NASA's Goddard Space Flight Center in Greenbelt, Md., who shows a loss of about 10 percent per decade since the beginning of the satellite record in 1979. Scientists want to know where this loss is occurring.

"The decline of the multiyear ice cover of the last several decades has not been quantitatively explained," Kwok said.

To investigate the loss of multiyear ice, Kwok and Cunningham looked at a 17-year span of data from 1993 to 2009 from a range of polar-observing satellites and instruments, including NASA's Quick Scatterometer (QuikScat); the Ice, Cloud and land Elevation Satellite (ICESat); the Advanced Microwave Scanning Radiometer (AMSR); and the European Space Agency's European Remote Sensing (ERS)-1 and -2 satellites. Some instruments track ice coverage, while others track motion and concentration.

The team collected satellite images and tracked pixels of multiyear ice from April 1, prior to the onset of seasonal melt, and into the summer. Pixels that deviated away from images of the ice edge were considered lost to melt.

The team compared summertime melt of multiyear ice in the Beaufort Sea with estimates of ice lost from the Arctic basin through the Fram Strait -- a major passage through which ice can exit the Arctic Ocean. The comparison revealed how much multiyear ice was lost to export and how much was lost to melt.

They found that over the 17-year period, an area of 947,000 square kilometers (365,639 square miles), or about 32 percent of the decline in multiyear sea ice area, was lost in the Beaufort Sea due to melt.

A similar calculation using thickness estimates from NASA's ICESat from 2004 to 2009 show a volume loss of 1,400 cubic kilometers (336 cubic miles), or about 20 percent of the total loss by volume.

How and where multiyear ice is lost has impacts on the Arctic system. For example, more loss by melt means more freshwater remains in local Arctic waters rather than being transported southward.

"These results also show that thick multiyear sea ice is not immune to melt in the Pacific sector of the Arctic Ocean in today's climate," Kwok said.

The additional freshwater from melt in the Pacific sector, which encompasses the area of study, could contribute to the freshening of the Beaufort Gyre and potentially influence circulation, but the degree of that influence remains uncertain.

Not all of the multiyear ice loss is accounted for, however. Ice loss through Fram Strait and from melt from 2005 to 2008 accounts for just 52 percent of total ice loss. The team suggests that melt in other Arctic regions and outflow through other passages besides Fram Strait could account for the difference.

Since its launch in 1999, QuikScat, developed and managed by JPL, has advanced Earth science research and helped improve environmental predictions using measurements of global radar backscatter from Earth's ocean, land and ice surfaces. QuikScat data help scientists better understand and predict the processes that drive our climate, such as ocean circulation and the global water cycle. In addition to its numerous weather forecasting and climate research applications, QuikScat data also help monitor changes in Arctic sea ice and icebergs, as well as snow and soil moisture changes on land. For more on QuikScat, visit:

For more information, see:

› Missing 'Ice Arches' Contributed to 2007 Arctic Ice Loss

› NASA Satellite Reveals Dramatic Arctic Ice Thinning

› Satellites Show Arctic Literally on Thin Ice

Wednesday, November 3, 2010

NASA Spacecraft on Final Approach Toward Comet

EPOXI navigation team members and engineers in mission control at JPL
EPOXI navigation team members and engineers were in mission control for the final flight-path maneuver before the spacecraft's planned Nov. 4 flyby of comet Hartley 2. › Larger image
The EPOXI mission spacecraft has refined its path toward a Nov. 4 flyby of comet Hartley 2, successfully performing its final maneuver today at 8 a.m. PDT (11 a.m. EDT). The spacecraft burned its engines for 6.8 seconds, changing the spacecraft's velocity by 1.4 meters per second (3 miles per hour).

"I've worked the Stardust flyby of comet Wild 2 and the Deep Impact encounter with comet Tempel 1, and I have never seen a comet flit around the sky like this one," said mission navigator Shyam Bhaskaran of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We needed to make this burn to re-locate the spacecraft for the 700-kilometer [about 435 miles] flyby distance."

Part of the reason Hartley 2 is hard to pin down is because the small comet is very active.

"Hartley 2 is one-seventh the size of comet Tempel 1, but it releases almost the same amount of material into the space environment," said EPOXI Principal Investigator Mike A'Hearn of the University of Maryland. "These jets can act as thrusters and actually make small changes to the comet's orbit around the sun."

On Thursday, Nov. 4, the spacecraft will fly past the comet, with closest approach expected about 7 a.m. PDT [10 a.m. EDT]. This flyby will mark the fifth time in history that a spacecraft has been close enough to image the heart of the comet, more commonly known as the nucleus.

EPOXI is an extended mission that uses the already "in-flight" Deep Impact spacecraft to explore distinct celestial targets of opportunity. The name EPOXI itself is a combination of the names for the two extended mission components: the extrasolar planet observations, called Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft will continue to be referred to as "Deep Impact."

JPL, a division of the California Institute of Technology in Pasadena, manages the EPOXI mission for NASA's Science Mission Directorate, Washington. The University of Maryland, College Park, is home to the mission's principal investigator, Michael A'Hearn. Drake Deming of NASA's Goddard Space Flight Center, Greenbelt, Md., is the science lead for the mission's extrasolar planet observations. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information about EPOXI, visit: and

View my last 3 blog postings...

The Man Behind Comet Hartley 2

Malcolm Hartley, comet discoverer
Malcolm Hartley of the Anglo-Australian Observatory, Siding Spring, New South Whales, Australia. › Larger image
Over the last 40 years, Malcolm Hartley has done just about every possible job for Siding Spring Observatory's UK Schmidt telescope in New South Wales, Australia. The British-born, Scottish-educated Hartley has logged time as the 1.2 meter (3.9 foot) telescope's observer, processor, copier, hypersensitization expert, and quality controller.

On the afternoon of March 16, 1986, Hartley's job was that last one -- quality control. In that role, he was the first to view each 36-by-36 centimeter (14-by-14 inch) photographic glass plate after it had been exposed to the night sky. Checking for imperfections on one of the previous evening's 60-minute illuminations, Hartley came upon something that wasn't supposed to be there.

"Back then, the observations came in as negatives -- stars and other objects in the sky appeared black on a clear background," said Hartley. "I noticed a dark haze around a trail. Trails indicate something that is traveling fast through the sky, but asteroids don't have a haze. So I thought it might be a comet."

Hartley double-checked his sighting a couple of nights later, then submitted his findings to the Minor Planet Center in Cambridge, Mass. A couple of days after that, the center issued a brief circular informing the astronomical world of the discovery of comet Hartley 2.

"I was very happy for a couple of days," said Hartley."Every scientist wants to discover something and it's a fantastic feeling. There was even a mention in the local paper, the Coonabarabran Times."

On the world's stage, having a comet named after you is certainly unique. But not so much in the small town of Coonabarabran -- which they say comes from the local Aboriginal word for 'inquisitive person.' It is the closest town to the Warrumbungle Range and Siding Spring Mountain and the Anglo-Australian Observatory.

"There are several other colleagues at Siding Springs who have discovered comets," Hartley said. "Robert McNaught has discovered over 50, and I don't think he's ever been mentioned in the Times. It's a rural farming community, and while there are amateur astronomers in the area, finding comets is not really a big deal."

Hartley went on to discover or co-discover 10 comets with the UK Schmidt telescope, and with each, he would feel an initial rush of excitement. But in 2002, the Anglo-Australian Observatory retrofitted its Schmidt to perform multi-object spectroscopy, essentially halting all astrophotography with the telescope and ending any future possibility for comet discovery. Hartley, who never was directly tasked with finding comets, continued to work the telescope's galaxy surveys. Comets, it seemed, had become little more than a historical footnote in his career. That is, until he got a call from a science magazine.

"At the beginning of last year, a reporter emailed and said that the EPOXI mission changed its target and now it was going to go to Hartley 2," said Hartley. "I didn't even know Hartley 2 was one of the two comets under consideration."

Hartley 2 was definitely on NASA's very short list of potential comet targets. The only problem with Hartley 2 was it would take more than two years of extra deep-space cruising to get there. So the only other candidate on the short list, the similar-sized comet Boethin, was selected. That is, until it disappeared. Scientists theorize that comet Boethin had broken into non-traceable fragments. This situation left NASA's short list as a list of one -- comet Hartley 2.

So Malcolm Hartley did what anybody would do who has a namesake comet that was just selected as a target for a NASA comet flyby, after the previous selection had disappeared. He thanked the reporter, logged off his computer and wondered what "his comet" would look like. Whatever that was going to be, Hartley was sure he would find out from the comfort of his living room. Then NASA called.

"I've never been involved with a space mission," said Hartley. "I had never visited JPL or any NASA facility for that matter. So this is all new to me. I am very grateful you have asked me to come and witness this. It is an experience very few people have had before."

Exactly once before -- of all the approximately 3,800 known comets, four have been imaged closeup by spacecraft. And of those four, only Swiss astronomer Paul Wild (pronounced "Vilt") was alive to see his comet visited. And while Wild witnessed the launch of NASA 's Stardust spacecraft from Cape Canaveral, Fla., in 1999, he watched the close-up images of his comet from the comfort of his living room in 2003. (Wild passed away in 2008). Hartley will see his comet from JPL's mission control room.

"When I discovered the comet in 1986, I never envisaged that I would come to the location where the mission was run, to see it up-close and personal," said Hartley, who was a boy when JPL was starting up.

Not surprisingly, the 63-year-old astrophotographer also has some thoughts on the mission to his comet.

"You went to Tempel 1, but then you reconfigured the spacecraft for the extended mission," said Hartley. "That's pretty clever stuff that you've done. That's the kind of science that's really interesting. To be able to do something extra on top of the successful mission you mounted at Tempel 1, it's really special."

EPOXI is an extended mission that utilizes the already "in-flight" Deep Impact spacecraft to explore distinct celestial targets of opportunity. The term EPOXI is a combination of the names for the two extended mission components: the Extrasolar Planet Observations and Characterization (EPOCh), and the Hartley 2 flyby, called the Deep Impact eXtended Investigation (DIXI). For more information about EPOXI, visit: and

JPL, a division of the California Institute of Technology in Pasadena, manages the EPOXI mission for NASA.

View my last 3 blog postings...

Monday, November 1, 2010

NASA's Comet Mission May Face Multiple Jets Nov. 4

Jets emanating from comet Hartley 2
The Deep Impact spacecraft's High- and Medium-Resolution Imagers (HRI and MRI) have captured multiple jets emanating from comet Hartley 2 turning on and off while the spacecraft is 8 million kilometers (5 million miles) away from the comet. The movies from HRI and MRI show the progression of two jets during a 16-hour time period.
Two movies derived from images taken by the two cameras aboard NASA's EPOXI mission spacecraft show comet Hartley 2 is, as expected, quite active, and it provides information on the nucleus's rotation. The spacecraft has been imaging Hartley 2 almost daily since Sept. 5, in preparation for its scheduled Nov. 4 flyby of the comet.

"The comet brings us new surprises every day," said Michael A'Hearn, EPOXI principal investigator from the University of Maryland, College Park. "The data we have received to this point have been tremendous. It is forcing us to rethink what we know about cometary science, and we are still days away from encounter."

On Oct. 26, the spacecraft's two cameras, a High-Resolution Imager (HRI), and a Medium-Resolution-Imager (MRI), caught two jets firing off the comet's surface over a 16-hour period. The spacecraft captured these images from a distance of about 8 million kilometers (5 million miles) away. The data lead mission scientists to believe that both jets originate from similar latitudes on the comet's nucleus.

"These movies are excellent complements of one and other and really provide some excellent detail of how a comet's jets operate," said A'Hearn. "Observing these jets from EPOXI provides an entirely different viewpoint from what is available for Earth-based observers and will ultimately allow a proper three-dimensional reconstruction of the environment surrounding the nucleus."

The name EPOXI is a combination of the names for the two extended mission components: the extrasolar planet observations, called Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft will continue to be referred to as "Deep Impact." The Deep Impact mission successfully deployed a projectile into the path of comet Tempel 1 in 1995. The spacecraft is being "recycled" for the comet Hartley 2 flyby.

JPL manages the EPOXI mission for NASA's Science Mission Directorate, Washington. The University of Maryland, College Park, is home to the mission's principal investigator, Michael A'Hearn. Drake Deming of NASA's Goddard Space Flight Center, Greenbelt, Md., is the science lead for the mission's extrasolar planet observations. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information about EPOXI visit and

View my last 3 blog postings...

Thursday, October 28, 2010

NASA Spacecraft Preps for Comet Flyby

Epoxi team members in mission control
Navigators and mission controllers for NASA’s EPOXI mission communicated with the spacecraft for a trajectory correction maneuver on October 27, 2010. › Larger image
In one of its final mission trajectory correction maneuvers, the EPOXI mission spacecraft has refined its orbit, preparing it for the flyby of comet Hartley 2 on Nov. 4. The time of closest approach to the comet on that day is expected to be about 7:02 a.m. PDT (10:02 a.m. EDT).

Today's trajectory correction maneuver began at 11 a.m. PDT (2 p.m. EDT), when the spacecraft burned its engines for 60 seconds, changing its velocity by 1.59 meters per second (3.6 miles per hour).

On Nov. 4, the spacecraft will fly past Hartley 2 at a distance of about 700 kilometers (435 miles). It will be only the fifth time in history that a spacecraft has been close enough to image a comet's nucleus.

EPOXI is an extended mission that uses the already "in-flight" Deep Impact spacecraft to explore distinct celestial targets of opportunity. The name EPOXI itself is a combination of the names for the two extended mission components: the extrasolar planet observations, called Extrasolar Planet Observations and Characterization (EPOCh); and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft will continue to be referred to as "Deep Impact."

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the EPOXI mission for NASA's Science Mission Directorate, Washington. The University of Maryland, College Park, is home to the mission's principal investigator, Michael A'Hearn. Drake Deming of NASA's Goddard Space Flight Center, Greenbelt, Md., is the science lead for the mission's extrasolar planet observations. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information about EPOXI, visit: .

View my last 3 blog postings...

Space Buckyballs Thrive, Finds NASA Spitzer Telescope

infrared photo of the Small Magellanic Cloud taken by Spitzer
An infrared photo of the Small Magellanic Cloud taken by Spitzer is shown here in this artist's illustration, with two callouts. The middle callout shows a magnified view of an example of a planetary nebula, and the right callout shows an even further magnified depiction of buckyballs, which consist of 60 carbon atoms arranged like soccer balls. › Full image and caption
Astronomers have discovered bucket loads of buckyballs in space. They used NASA's Spitzer Space Telescope to find the little carbon spheres throughout our Milky Way galaxy -- in the space between stars and around three dying stars. What's more, Spitzer detected buckyballs around a fourth dying star in a nearby galaxy in staggering quantities -- the equivalent in mass to about 15 of our moons.

Buckyballs, also known as fullerenes, are soccer-ball-shaped molecules consisting of 60 linked carbon atoms. They are named for their resemblance to the architect Buckminster Fuller's geodesic domes, an example of which is found at the entrance to Disney's Epcot theme park in Orlando, Fla. The miniature spheres were first discovered in a lab on Earth 25 years ago, but it wasn't until this past July that Spitzer was able to provide the first confirmed proof of their existence in space. At that time, scientists weren't sure if they had been lucky to find a rare supply, or if perhaps the cosmic balls were all around.

"It turns out that buckyballs are much more common and abundant in the universe than initially thought," said astronomer Letizia Stanghellini of the National Optical Astronomy Observatory in Tucson, Ariz. "Spitzer had recently found them in one specific location, but now we see them in other environments. This has implications for the chemistry of life. It's possible that buckyballs from outer space provided seeds for life on Earth."

Stanghellini is co-author of a new study appearing online Oct. 28 in the Astrophysical Journal Letters. Anibal García-Hernández of the Instituto de Astrofísica de Canarias, Spain, is the lead author of the paper. Another Spitzer study about the discovery of buckyballs in space was also recently published in the Astrophysical Journal Letters. It was led by Kris Sellgren of Ohio State University, Columbus.

The García-Hernández team found the buckyballs around three dying sun-like stars, called planetary nebulae, in our own Milky Way galaxy. These cloudy objects, made up of material shed from the dying stars, are similar to the one where Spitzer found the first evidence for their existence.

The new research shows that all the planetary nebulae in which buckyballs have been detected are rich in hydrogen. This goes against what researchers thought for decades -- they had assumed that, as is the case with making buckyballs in the lab, hydrogen could not be present. The hydrogen, they theorized, would contaminate the carbon, causing it to form chains and other structures rather than the spheres, which contain no hydrogen at all. "We now know that fullerenes and hydrogen coexist in planetary nebulae, which is really important for telling us how they form in space," said García-Hernández.

García-Hernández and his colleagues also located buckyballs in a planetary nebula within a nearby galaxy called the Small Magellanic Cloud. This was particularly exciting to the researchers, because, in contrast to the planetary nebulae in the Milky Way, the distance to this galaxy is known. Knowing the distance to the source of the buckyballs meant that the astronomers could calculate their quantity -- two percent of Earth's mass, or the mass of 15 of our moons.

The other new study, from Sellgren and her team, demonstrates that buckyballs are also present in the space between stars, but not too far away from young solar systems. The cosmic balls may have been formed in a planetary nebula, or perhaps between stars. A feature story about this research is online at .

"It’s exciting to find buckyballs in between stars that are still forming their solar systems, just a comet’s throw away," Sellgren said. "This could be the link between fullerenes in space and fullerenes in meteorites."

The implications are far-reaching. Scientists have speculated in the past that buckyballs, which can act like cages for other molecules and atoms, might have carried substances to Earth that kick-started life. Evidence for this theory comes from the fact that buckyballs have been found in meteorites carrying extraterrestial gases.

"Buckyballs are sort of like diamonds with holes in the middle," said Stanghellini. "They are incredibly stable molecules that are hard to destroy, and they could carry other interesting molecules inside them. We hope to learn more about the important role they likely play in the death and birth of stars and planets, and maybe even life itself."

The little carbon balls are important in technology research too. They have potential applications in superconducting materials, optical devices, medicines, water purification, armor and more.

Other authors of the García-Hernández study are Arturo Manchado, the Instituto de Astrofísica de Canarias; Pedro García-Lario, European Space Agency Centre, Spain; Eva Villaver, Universidad Autónoma de Madrid, Spain; Richard Shaw, National Optical Astronomy Observatory; Ryszard Szczerba, Nicolaus Copernicus Astronomical Center, Poland; and José V. Perea-Calderon, European Space Astronomy Centre, Ingeniería y Servicios Aerospaciales, Spain.

Other authors of the Sellgren study are Michael Werner, Spitzer project scientist, NASA's Jet Propulsion Laboratory, Pasadena, Calif.; James Ingalls, NASA's Spitzer Science Center at the California Institute of Technology in Pasadena.; J.D.T. Smith, University of Toledo, Ohio; T.M. Carleton, University of Arizona, Tucson; and Christine Joblin, Université de Toulouse, France.

The Spitzer observations were made before it ran out of its liquid coolant in May 2009 and began its warm mission. JPL manages the Spitzer mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center. Caltech manages JPL for NASA. For more information about Spitzer, visit and .

View my last 3 blog postings...

NASA Goddard Delivers Magnetometers for Juno Mission

Juno and Jupiter artist's depiction
NASA's Juno spacecraft passes in front of Jupiter in this artist's depiction. Juno, the second mission in NASA's New Frontiers program, will improve our understanding of the solar system by advancing studies of the origin and evolution of Jupiter. › Full image and caption
Magnetometers developed at NASA's Goddard Space Flight Center in Greenbelt, Md., for the Juno mission to Jupiter were delivered recently to Lockheed Martin in Denver. Designed and built by an in-house team of Goddard scientists, engineers and technicians, these instruments will map the planet's magnetic field with great accuracy and observe its variations over time. Each of the two vector magnetometers carries with it a pair of non-magnetic star cameras to determine its orientation in space with commensurate accuracy. These were designed and built by a team led by John Jorgensen at the Danish Technical University in Copenhagen, Denmark.

"Juno's magnetometers will measure Jupiter's magnetic field with extraordinary precision and give us a detailed picture of what the field looks like, both around the planet and deep within," says Goddard's Jack Connerney, the mission's deputy principal investigator and head of the magnetometer team. "This will be the first time we've mapped the magnetic field all around Jupiter-it will be the most complete map of its kind ever obtained about any planet with an active dynamo, except, of course, our Earth."

The Jet Propulsion Laboratory in Pasadena, Calif., manages the Juno mission for NASA. Scheduled for launch in 2011, Juno is the second mission in NASA's New Frontiers program. The mission will improve our understanding of the solar system by advancing studies of the origin and evolution of Jupiter. The spacecraft will carry nine instruments to investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras.

"The magnetometers play a unique and important role in Juno's investigation of the formation and evolution of Jupiter," says Juno's principal investigator, Scott Bolton of Southwest Research Institute in San Antonio. "They provide one of the ways that Juno will see deep inside the giant planet, and this will help us understand how and where Jupiter's powerful magnetic field is generated."

The Juno magnetometers will study Jupiter's powerful magnetic field, which is nearly 20,000 times as strong as Earth's. The field is generated deep within the planet's atmosphere, where the intense pressure compresses hydrogen gas into an electrically conductive fluid. Fluid motion within the planet drives electric currents in this liquid hydrogen, and these currents generate the magnetic field. If a map were drawn of the magnetic field lines running between Jupiter's north and south poles, the region of space filled by the lines (called the magnetosphere) would be enormous. Jupiter's magnetosphere extends up to 3 million kilometers (nearly 2 million miles) toward the sun and as far as Saturn's orbit in the other direction.

"From a distance, Jupiter's magnetic field has two poles, north and south, like Earth's. But looking closer, below Jupiter's surface, the magnetic field is thought to be quite complex and tangled," says Connerney. "Juno will give us a detailed picture of the magnetic field extending down to the surface of the dynamo, or engine, that generates it."

Jupiter's powerful magnetic environment also creates the brightest auroras in the solar system, as charged particles get trapped by the field and rain down into the atmosphere. Juno will directly sample the charged particles and magnetic fields near Jupiter's poles for the first time, while simultaneously observing the auroras at ultraviolet wavelengths of light. These investigations will greatly improve the understanding of this remarkable phenomenon and of similar magnetic objects, such as young stars that have their own planetary systems.

"With Juno, we will learn much more about the structure and evolution of Jupiter, and this will help us understand our own solar system," says Connerney. "But astronomers have now found many other giant planets outside our solar system. What we learn about Jupiter also will help us understand the planets orbiting other stars."

Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft. The Italian Space Agency in Rome is contributing an infrared spectrometer instrument and a portion of the radio science experiment.

For more information about Juno, visit: .

For information about NASA and agency programs, visit: .

View my last 3 blog postings...

Wednesday, October 27, 2010

NASA's Kepler Spacecraft Takes Pulse of Distant Stars

Artist's concept of Kepler
Artist's concept of Kepler in the distant solar system.
An international cadre of scientists using datafrom NASA's Kepler spacecraft has detected stellar oscillations, or "starquakes," that yield new insights about the size, age and evolution of stars.

The results were presented at a news conference at Aarhus University in Denmark by scientists representing the Kepler Asteroseismic Science Consortium. The team studied thousands of stars observed by Kepler, releasing what amounts to a roster of some of humanity's most well-characterized stars.

Analysis of stellar oscillations is similar to the way seismologists study earthquakes to probe the Earth's interior. This branch of science, called astroseismology, produces measurements of stars the Kepler science team is anxious to have.

"Using the unparalleled data provided by Kepler, Asteroseismic Science Consortium scientists are quite literally revolutionizing our understanding of stars and their structures," said Douglas Hudgins, Kepler Program Scientist at NASA Headquarters in Washington.

One oscillating star has taken center stage: KIC 11026764 has the most accurately known properties of any star in the Kepler field. In fact, few stars in the universe are known to similar accuracy. At an age of 5.94 billion years, it has grown to a little over twice the diameter of the sun and it will continue to grow as it transforms into a red giant. The oscillations reveal that this star is powered by hydrogen fusion in a thin shell around a helium-rich core.

Launched in March 2009, Kepler was designed to discover Earth-size planets orbiting other stars. The spacecraft uses a huge digital camera, known as a photometer, to continuously monitor the brightness of more than 150,000 stars in its field of view as it orbits around the sun. Kepler searches for distant worlds by looking for "transits," when a planet passes in front of a star, briefly causing it to dim. The amount of dimming reveals the size of the planet compared to the size of the star.

Ames is responsible for the ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed the Kepler mission development. Ball Aerospace and 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 the Kepler science data.

Read full news release at: .

More information about Kepler is online at: and .

View my last 3 blog postings...

Monday, October 25, 2010

Five Things About NASA's EPOXI Mission

Artist's concept of Deep Impact's encounter with comet Temple 1
This artist's concept shows us the first time Deep Impact encountered a comet - Tempel 1 in July 2005. Deep Impact, now in an extended mission called EPOXI, will fly by its next comet, Hartley 2, on Nov. 4, 2010. Full image and caption

Here are five quick facts about the EPOXI mission, scheduled to fly by comet Hartley 2 on Nov. 4, 2010.

1. High Fives - This is the fifth time humans will see a comet close-up, and the Deep Impact spacecraft flew by Earth for its fifth time on Sunday, June 27, 2010.

2. Eco-friendly Spacecraft: Recycle, Reuse, Record - The EPOXI mission is recycling the Deep Impact spacecraft, whose probe intentionally collided with comet Tempel 1 on July 4, 2005, revealing, for the first time, the inner material of a comet. The spacecraft is now approaching a second comet rendezvous, a close encounter with Hartley 2 on Nov. 4. The spacecraft is reusing the same trio of instruments used during Deep Impact: two telescopes with digital imagers to record the encounter, and an infrared spectrometer.

3. Small, Mighty and Square-Dancing in Space - Although comet Hartley 2 is smaller than Tempel 1, the previous comet visited by Deep Impact, it is much more active. In fact, amateur skywatchers may be able to see Hartley 2 in a dark sky with binoculars or a small telescope. Engineers specifically designed the mighty Deep Impact spacecraft to point a camera at Tempel 1 while its antenna was directed at Earth. This flyby of comet Hartley 2 does not provide the same luxury. It cannot both photograph the comet and talk with mission controllers on Earth. Engineers have instead programmed Deep Impact to dance the do-si-do. The spacecraft will spend the week leading up to closest approach swinging back and forth between imaging the comet and beaming images back to Earth.

4. Storytelling Comets - Comets are an important aspect of studying how the solar system formed and Earth evolved. Comets are leftover building blocks of solar system formation, and are believed to have seeded an early Earth with water and organic compounds. The more we know about these celestial bodies, the more we can learn about Earth and the solar system.

5. What's in a Name? - EPOXI is a hybrid acronym binding two science investigations: the Extrasolar Planet Observation and Characterization (EPOCh) and Deep Impact eXtended Investigation (DIXI). The spacecraft keeps its original name of Deep Impact, while the mission is called EPOXI.

View my last 3 blog postings...

Watch Construction of Nasa's New Mars Rover Live on the Web

The Curiosity Cam live video feed allows the public to watch technicians assemble and test NASA's next Mars rover in a clean room at the Jet Propulsion Laboratory, Pasadena, Calif.
The Curiosity Cam live video feed allows the public to watch technicians assemble and test NASA's next Mars rover in a clean room at the Jet Propulsion Laboratory, Pasadena, Calif.

A newly installed webcam is giving the public an opportunity to watch technicians assemble and test the next NASA Mars rover, one of the most technologically challenging interplanetary missions ever designed.

NASA's Mars Science Laboratory, also known as the Curiosity rover, is in a clean room at the agency's Jet Propulsion Laboratory in Pasadena, Calif. The webcam, affectionately called "Curiosity Cam," provides the video feed, without audio, from a viewing gallery above the clean room floor. The video will be supplemented periodically by live Web chats featuring Curiosity team members answering questions about the rover. Currently, work in the clean room begins at 8 a.m. PDT Monday through Friday.

Assembly engineers and technicians have been busy adding new avionics and instruments to the rover. Beginning Friday, viewers will see the assembly team carefully install the rover's suspension system and its six wheels. On Tuesday, the rover's 7-foot-long robotic arm will be carefully lifted and attached to the front of the rover.

Continuous live video of rover construction is available at: . The feed is also available at and . The camera shows a portion of the clean room that is typically active; but the rover, spacecraft components and technicians may move out of view as work shifts to other areas of the room. When activity takes place in other testing facilities around JPL, the clean room may be empty. The camera may also be turned off periodically for maintenance or technical issues.

Months of assembly and testing remain before the car-sized rover is ready for launch from Cape Canaveral, Fla. The rover and spacecraft components will ship to NASA's Kennedy Space Center in Florida in spring of 2011. The launch will occur between Nov. 25 and Dec. 18, 2011. Curiosity will arrive on Mars in August 2012.

Curiosity is engineered to drive longer distances over rougher terrain than previous rovers with a science payload 10 times the mass of instruments on NASA's Spirit and Opportunity. The new, large rover will investigate whether the landing region has had environments favorable for supporting microbial life and for preserving evidence about whether life existed on the Red Planet.

For information and news about Curiosity, visit: or

Social media audiences can learn more about the mission on Twitter at and on Facebook at

View my last 3 blog postings...