NASA JPL mission to send quadcopter drone to search for life on Titan

Although Titan's landscape presents one of the more intriguing potential habitats for life in our solar system, there are plenty of reasons to be skeptical.

The moon's seas are comprised of liquid ethane or methane, while the atmosphere is much colder than Earth's and made up of hydrogen cyanide.

While NASA Cassini probe whizzes by Saturn's moon Titan on Thursday to analyze its atmosphere, the American space agency is also considering a plan to send a quadcopter drone capable of searching for life.

The ambitious idea was outlined by Larry Matthies, a research scientist and supervisor at NASA's Jet Propulsion Lab in California, and involves a drone that would be capable of flying out of a lander or balloon.

The drone would explore the moon's landscape and seas, collect samples, and return to the "mothership" to recharge its batteries and submit whatever it collects for analysis.

If successful, the new plan could drastically change the way humans explore space.

Current rovers on Mars are akin to moving laboratories, but their grounded nature means they can be rather limited when it comes to exploring terrain.

The 22-pound drone conceived by Matthies would eliminate that barrier with flight capability, allegedly at much lower costs than other options.

As quoted by Gizmodo, he described the plan as follows: "We propose a mission study of a small (10 kg) rotorcraft that can deploy from a balloon or lander to acquire close-up, high resolution imagery and mapping data of the surface, land at multiple locations to acquire microscopic imagery and samples of solid and liquid material, return the samples to the mothership for analysis, and recharge from an RTG on the mothership to enable multiple sorties."

Matthies also noted that while this kind of plan would not have been feasible even just a few years ago, advancements in drone technology and other robotics have "revolutionized" older mission concepts, meaning sending a drone capable of exploring Titan is now a real possibility.

Options are also available regarding exactly what form the mission takes. NASA could either have the drone operate out of an airborne balloon-like mothership or out of a land-based vehicle.

"For a lander mission, it enables detailed studies of a large area around the lander, providing context for the micro-images and samples; with precision landing near a lake, it potentially enables sampling solid and liquid material from one lander," he said.

"For a balloon mission, it enables surface investigation and sampling with global reach without requiring a separate lander or that the balloon be brought to the surface, which has potential for major cost savings and risk reduction."

According to the Huffington Post, NASA has awarded Matthies' team $100,000 to continue working on designs for the unmanned concept, which includes a mothership outfitted with a nuclear reactor.

Still, any lift-off dates are still a long ways into the future. Although technology has gotten to the point where such a plan can be planned, it still needs to be developed further. The agency is hoping a launch sometime in the 2040s would be possible.


Meanwhile, NASA's Cassini probe is scheduled to fly by Titan on Thursday and bounce radio signals off its surface for the second time in two months.

The mission is intended to reveal more information about the moon's atmosphere and lakes, which could come in handy for future missions and determining whether life could exist in its hydrocarbon seas.

"We held our breath as Cassini turned to beam its radio signals at the lakes," Cassini radio science team member Essam Marouf said, referring to the May mission.

"We knew we were getting good quality data when we saw clear echoes from Titan's surface. It was thrilling."

Although Titan's landscape presents one of the more intriguing potential habitats for life in our solar system, there are plenty of reasons to be skeptical.

The moon's seas are comprised of liquid ethane or methane, while the atmosphere is much colder than Earth's and made up of hydrogen cyanide.

Cassini has, however, revealed the possibility that liquid water may exist under the moon's icy shell, and there's speculation other forms of life could be present.

Starshade: Space sunflower will help snap pictures of planets

The prototype Starshade, a giant structure designed to block the glare of stars so that future space telescopes can take pictures of planets.

A spacecraft that looks like a giant sunflower might one day be used to acquire images of Earth-like rocky planets around nearby stars.

The prototype deployable structure, called a starshade, is being developed by NASA's Jet Propulsion Laboratory in Pasadena, Calif.

The hunt is on for planets that resemble Earth in size, composition and temperature. Rocky planets with just the right temperature for liquid water—not too hot, not too cold—could be possible abodes for life outside our solar system.

NASA's Kepler mission has discovered hundreds of planets orbiting other stars, called exoplanets, some of which are a bit larger than Earth and lie in this comfortable "Goldilocks" zone.

Researchers generally think it's only a matter of time before we find perfect twins of Earth. The next step would be to image and characterise their spectra, or chemical signatures, which provide clear clues about whether those worlds could support life.

The Starshade is designed to help take those pictures of planets by blocking out the overwhelmingly bright light of their stars.

Simply put, the Starshade is analogous to holding your hand up to the sun to block it while taking a picture of somebody.

The proposed Starshade could launch together with a telescope. Once in space, it would separate from the rocket and telescope, unfurl its petals, then move into position to block the light of stars.

Mars Missions: JPL Test New Supersonic Decelerator Technology - Video

Video of rocket-sled testing of the SIAD-R device, conducted in fall 2012 at China Lake, Calif. 

The SIAD-R is one of three supersonic deceleration devices now being prepared for flight testing by the Low-Density Supersonic Decelerator project at NASA's Jet Propulsion Laboratory in Pasadena, Calif. 

The devices, which slow the rate of descent for vehicles entering the atmosphere of another planet, could be used in Mars missions launching as early as 2018.

Validation tests are crucial to working out the kinks before a system of this type is used for future space missions.

A giant crane will tower above NASA's Jet Propulsion Laboratory in Pasadena, Calif., shooting out of a hilly mesa like an oversized erector set, ready to help test components of NASA's Low Density Supersonic Decelerator (LDSD) project.

The goal of the challenging technology, led by JPL, is to enable a future mission to Mars or other planetary bodies that uses heavier spacecraft and lands them at locations that were previously not achievable.

The crane-test is scheduled for tomorrow, Dec. 18, weather permitting. The test will simulate the acceleration of a large parachute being pulled away from a spacecraft.

The purpose of the test is to show that all of the parachute lines and bridles come out in an organized manner and do not catch on other vehicle hardware as they are deployed.

NASA's Low-Density Supersonic Decelerator team gathers around the "SIAD-R" -- a Supersonic Inflatable Aerodynamic Decelerator they're developing to assist future planetary exploration missions -- during rocket-sled testing at China Lake, Calif. 

Image Credit: NASA/JPL

Validation tests are crucial to working out the kinks before a system of this type is used for future space missions. During this test, the parachute, which has a diameter of roughly 100 feet (30.5 meters), will not open.

Its size is a significant upgrade by comparison to parachutes that have come before it. For instance, last year's successful landing of NASA's Mars Curiosity Rover utilized a parachute that measured only 51 feet (15.5 meters) across, about half the size.

The heavier planetary landers of the future require much larger drag devices than any now in use to slow them down -- and those next-generation drag devices will need to be deployed at higher supersonic speeds to safely land a vehicle, plus crew and cargo for potential human missions.

Artist impression of SIAD-R over Mars

Current Mars landing techniques date back to NASA's Viking mission, which put two landers on Mars in 1976.

That mission's basic parachute design has been in use ever since, with additional landing technologies, and was used again in 2012 to deliver the Curiosity rover to Mars.

To conduct more massive exploration missions in the future, however, NASA must advance the technology to a new level of sophistication.

Testing for the LDSD project began in 2012 at the U.S. Navy's China Lake Naval Air Weapons Station in California and will be conducted through 2015.

In the next few years, the Low Density Supersonic Decelerator Technology Demonstration Mission will conduct full-scale, stratospheric tests of these breakthrough technologies high above Earth to prove their value for future space exploration missions.

NASA Mars Curiosity Rover: MMRTG likely cause of electronic short

This artist concept features NASA's Mars Science Laboratory Curiosity rover, a mobile robot for investigating Mars' past or present ability to sustain microbial life. 

In this picture, the mast, or rover's "head," rises to about 2.1 meters (6.9 feet) above ground level, about as tall as a basketball player.

This mast supports two remote-sensing instruments: the Mast Camera, or "eyes," for stereo color viewing of surrounding terrain and material collected by the arm; and, the ChemCam instrument, which is a laser that vaporizes material from rocks up to about 7 meters (23 feet) away and determines what elements the rocks are made of.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington.

NASA's Mars rover Curiosity resumed full science operations on Saturday, Nov. 23.

Activities over the weekend included use of Curiosity's robotic arm to deliver portions of powdered rock to a laboratory inside the rover.

The powder has been stored in the arm since the rover collected it by drilling into the target rock "Cumberland" six months ago.

Several portions of the powder have already been analyzed. The laboratory has flexibility for examining duplicate samples in different ways.

The decision to resume science activities resulted from the success of work to diagnose the likely root cause of a Nov. 17 change in voltage on the vehicle. The voltage change itself did not affect the rover safety or health.

The vehicle's electrical system has a "floating bus" design feature to tolerate a range of voltage differences between the vehicle's chassis—its mechanical frame—and the 32-volt power lines that deliver electricity throughout the rover. This protects the rover from electrical shorts.

"We made a list of potential causes, and then determined which we could cross off the list, one by one," said rover electrical engineer Rob Zimmerman of NASA's Jet Propulsion Laboratory, Pasadena, Calif. Science operations were suspended for six days while this analysis took priority.

The likely cause is an internal short in Curiosity's power source, the Multi-Mission Radioisotope Thermoelectric Generator (MMRTG).

Due to resilience in design, this short does not affect operation of the power source or the rover.

Similar generators on other spacecraft, including NASA's Cassini at Saturn, have experienced shorts with no loss of capability.

Testing of another MMRTG over many years found no loss of capability in the presence of these types of internal shorts.

Following the decision to resume science activities, engineers learned early Nov. 23 that the rover had returned to its pre-Nov. 17 voltage level.

This reversal is consistent with their diagnosis of an internal short in the generator on Nov. 17, and the voltage could change again.

The analysis work to determine the cause of the voltage change gained an advantage from an automated response by the rover's onboard software when it detected the voltage change on Nov. 17.

The rover stepped up the rate at which it recorded electrical variables, to eight times per second from the usual once per minute, and transmitted that engineering data in its next communication with Earth. "That data was quite helpful," Zimmerman said.

NASA Chandra Image: Elephant Trunk Nebula

Credit: X-ray: NASA/CXC/PSU/Getman et al, Optical: DSS, Infrared: NASA/JPL-Caltech

When radiation and winds from massive young stars impact clouds of cool gas, they can trigger new generations of stars to form.

This is what may be happening in this object known as the Elephant Trunk Nebula (or its official name of IC 1396A). 

X-rays from Chandra (purple) have been combined with optical (red, green, and blue) and infrared (orange and cyan) to give a more complete picture of this source.

NASA Deep Impact: Team attempts to restore communications

Artist's concept of NASA's Deep Impact spacecraft. 

Credit: NASA/JPL-Caltech

Ground controllers have been unable to communicate with NASA's long-lived Deep Impact spacecraft. Last communication with the spacecraft was on Aug. 8, 2013.

Deep Impact mission controllers will continue to uplink commands in an attempt to reestablish communications with the spacecraft.

Mission controllers postulate that there was an anomaly generated by the spacecraft's software which left the vehicle's computers in a condition where they are continuously rebooting themselves.

If this is the case, the computers would not continue to command the vehicle's thrusters to fire and hold attitude.

Lack of attitude hold makes attempts to reestablish communications more difficult because the orientation of the spacecraft's antennas is unknown.

It also brings into question the vehicle's electrical power status, as the spacecraft derives its power from a solar array that is fixed, with its cells pointing in one direction.

Deep Impact is history's most traveled deep-space comet hunter. It successfully completed its original mission and a subsequent extended mission.

Evidence of Alien Planets? No, It's Just Gas

The Fomalhaut system contains a cleared ring (shining brightly in this image) in the dust around the star. 

Scientists suspect that this gap was cleared by a pair of terrestrial planets, but new research reveals that the presence of gas could also create such a breach.

CREDIT: NASA, ESA, and P. Kalas (University of California, Berkeley)

Ring-shaped gaps in the gas around a newborn star system can trick astronomers into thinking that baby planets are forming there when they actually aren't, scientists say.

New simulations show that a sufficient concentration of gas in the disk around a young star could cause the dust to clump together to form rings, creating paths that resemble those cleared by newly formed exoplanets.

Gravity binds dust and rock together. The small clumps collect more material as they travel, eventually clearing out rings in their systems that scientists say could host alien planets.

Wladimir Lyra

These systems make good targets in the ongoing search for new worlds. But imaging such planets is a challenge because the light reflecting from them can be as much as a billion times dimmer than the light from their parent star.

"Directly imaged planets are among the hardest to find," said Wladimir Lyra, of NASA's Jet Propulsion Laboratory. "One solution is that they may simply not be there."

Planting false evidence
Spinning disks of dust and gas give rise to newborn stars. After the stars are formed, the remaining materialcan continue to collapse to create new solar systems.

"Disks start as a mixture of usually 100 times more gas than dust," Lyra told reporters. "When the star is formed, its light will slowly evaporate the gas, taking around 10 million years to dissipate it completely."

Marc Kuchner

Lyra and colleague Marc Kuchner of NASA's Goddard Space Flight Center studied how the gas and dust within these disks might interact by creating two- and three-dimensional models of such systems.

"The dust heats the gas by the photoelectric effect — an effect explained by Albert Einstein back in 1905 in a landmark paper that eventually led to the development of quantum mechanics," Lyra said.

NASA JPL CARVE: Arctic Permafrost the "Sleeping Giant" of Climate Change

Flying low and slow above the pristine terrain of Alaska's North Slope research scientist Charles Miller of NASA's Jet Propulsion Laboratory surveys the white expanse of tundra and permafrost below.

On the horizon, a long, dark line appears. His plane draws nearer, and the mysterious object reveals itself to be a massive herd of migrating caribou, stretching for miles.

"Seeing those caribou marching single-file across the tundra puts what we're doing here in the Arctic into perspective," says Miller, who is on five-year mission named "CARVE" to study how climate change is affecting the Arctic's carbon cycle.

CARVE is short for the "Carbon in Arctic Reservoirs Vulnerability Experiment."

Now in its third year, the airborne campaign is testing the hypothesis that Arctic carbon reservoirs are vulnerable to warming, while delivering the first source-maps of greenhouse gases carbon dioxide and methane. About two dozen scientists from 12 institutions are participating in this experiment.

"The Arctic is critical to understanding global climate," says Miller. "Climate change is already happening in the Arctic, faster than its ecosystems can adapt. Looking at the Arctic is like looking at the canary in the coal mine for the entire Earth system."

Over hundreds of millennia, Arctic permafrost soils have accumulated vast stores of organic carbon - an estimated 1,400 to 1,850 billion metric tons of it. That's about half of all the estimated organic carbon stored in Earth's soils.

In comparison, about 350 billion metric tons of carbon have been emitted from all fossil-fuel combustion and human activities since 1850. Most of the Arctic's sequestered carbon is located in thaw-vulnerable topsoils within 3 meters of the surface.

But, as scientists are learning, permafrost - and its stored carbon - may not be as permanent as its name implies. And that has them concerned.

"Permafrost soils are warming even faster than Arctic air temperatures - as much as 1.5 to 2.5 degrees Celsius in just the past 30 years," says Miller.

"As heat from Earth's surface penetrates into permafrost, it threatens to mobilize these organic carbon reservoirs and release them into the atmosphere as carbon dioxide and methane, upsetting the Arctic's carbon balance and greatly exacerbating global warming."

NASA NuSTAR: Black Hole Dormant Amidst Stellar Chaos

The Sculptor galaxy is seen in a new light, in this composite image from NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and the European Southern Observatory in Chile. 

Credit: NASA/JPL-Caltech/JHU

Nearly a decade ago, NASA's Chandra X-ray Observatory caught signs of what appeared to be a black hole snacking on gas at the middle of the nearby Sculptor galaxy.

Now, NASA's Nuclear Spectroscopic Telescope Array (NuSTAR), which sees higher-energy X-ray light, has taken a peek and found the black hole asleep.

"Our results imply that the black hole went dormant in the past 10 years," said Bret Lehmer of the Johns Hopkins University, Baltimore, and NASA's Goddard Space Flight Center, Greenbelt, Md.

"Periodic observations with both Chandra and NuSTAR should tell us unambiguously if the black hole wakes up again. If this happens in the next few years, we hope to be watching."

Lehmer is lead author of a new study detailing the findings in the Astrophysical Journal. The slumbering black hole is about 5 million times the mass of our sun.

It lies at the center of the Sculptor galaxy, also known as NGC 253, a so-called starburst galaxy actively giving birth to new stars.

At 13 million light-years away, this is one of the closest starbursts to our own galaxy, the Milky Way. The Milky Way is all around more quiet than the Sculptor galaxy.

It makes far fewer new stars, and its behemoth black hole, about 4 million times the mass of our sun, is also snoozing.

"Black holes feed off surrounding accretion disks of material. When they run out of this fuel, they go dormant," said co-author Ann Hornschemeier of Goddard.

"NGC 253 is somewhat unusual because the giant black hole is asleep in the midst of tremendous star-forming activity all around it."

The findings are teaching astronomers how galaxies grow over time. Nearly all galaxies are suspected to harbor supermassive black holes at their hearts.

In the most massive of these, the black holes are thought to grow at the same rate that new stars form, until blasting radiation from the black holes ultimately shuts down star formation.

In the case of the Sculptor galaxy, astronomers do not know if star formation is winding down or ramping up.

"Black hole growth and star formation often go hand-in-hand in distant galaxies," said Daniel Stern, a co-author and NuSTAR project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif.

"It's a bit surprising as to what's going on here, but we've got two powerful complementary X-ray telescopes on the case."

Chandra first observed signs of what appeared to be a feeding supermassive black hole at the heart of the Sculptor galaxy in 2003.

As material spirals into a black hole, it heats up to tens of millions of degrees and glows in X-ray light that telescopes like Chandra and NuSTAR can see.

Then, in September and November of 2012, Chandra and NuSTAR observed the same region simultaneously.

The NuSTAR observations -- the first-ever to detect focused, high-energy X-ray light from the region -- allowed the researchers to say conclusively that the black hole is not accreting material. NuSTAR launched into space in June of 2012.

In other words, the black hole seems to have fallen asleep. Another possibility is that the black hole was not actually awake 10 years ago, and Chandra observed a different source of X-rays.

Future observations with both telescopes may solve the puzzle.

For more information, visit: http://www.nasa.gov/nustar and http://www.nustar.caltech.edu/ .

Follow the mission on Twitter via http://www.twitter.com/NASANuSTAR .

ESA Herschel: Shining a light on cool pools of gas in the galaxy

This illustration shows a newfound reservoir of stellar fuel discovered by the Herschel space observatory (red). 

Credit: ESA/NASA/JPL-Caltech

Newly formed stars shine brightly, practically crying out, "Hey, look at me!" But not everything in our Milky Way galaxy is easy to see.

The bulk of material between the stars in the galaxy -- the cool hydrogen gas from which stars spring -- is nearly impossible to find.

A new study from the Hershel Space Observatory, a European Space Agency mission with important NASA participation, is shining a light on these hidden pools of gas, revealing their whereabouts and quantities.

In the same way that dyes are used to visualize swirling motions of transparent fluids, the Herschel team has used a new tracer to map the invisible hydrogen gas.

The discovery reveals that the reservoir of raw material for making stars had been underestimated before -- almost by one third -- and extends farther out from our galaxy's center than known before.

Jorge Pineda

"There is an enormous additional reservoir of material available to form new stars that we couldn't identify before," said Jorge Pineda of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead author of a new paper on the findings published in the journal Astronomy and Astrophysics.

"We had to go to space to solve this mystery because our atmosphere absorbs the specific radiation we wanted to detect," said William Langer of JPL, principal investigator of the Herschel project to map the gas.

"We also needed to see far-infrared light to pinpoint the location of the gas. For both these reasons, Herschel was the only telescope for the job."

Stars are created from clouds of gas, made of hydrogen molecules. The first step in making a star is to squeeze gas together enough that atoms fuse into molecules.

William Langer

The gas starts out sparse but, through the pull of gravity and sometimes other constricting forces, it collects and becomes denser.

When the hydrogen gets dense enough, nuclear fusion takes place and a star is born, shining with starlight.

Astronomers studying stars want to follow this journey, from a star's humble beginnings as a cloud of molecules to a full-blown blazing orb.

To do so requires mapping the distribution of the stellar hydrogen fuel across the galaxy.

Unfortunately, most hydrogen molecules in space are too cold to give off any visible light. They lurk unseen by most telescopes.

For decades, researchers have turned to a tracer molecule called carbon monoxide, which goes hand-in-hand with the hydrogen molecules, revealing their location, but this method has limitations.

In regions where the gas is just beginning to pool -- the earliest stage of cloud formation -- there is no carbon monoxide.

"Ultraviolet light destroys the carbon monoxide," said Langer. "In the space between stars, where the gas is very thin, there is not enough dust to shield molecules from destruction by ultraviolet light."

A different tracer -- ionized carbon -- does, however, linger in these large but relatively empty spaces, and can be used to pin down the hydrogen molecules.

Researchers have observed ionized carbon from space before, but Herschel has, for the first time, provided a dramatically improved geographic map of its location and abundance in the galaxy.

"Thanks to Herschel's incredible sensitivity, we can separate material moving at different speeds," said Paul Goldsmith, a co-author and the NASA Herschel Project Scientist at JPL. "We finally can get the whole picture of what's available to make future generations of stars."

Read a more in-depth story about this research from the European Space Agency at http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=51909 .

The technical paper is online at http://arxiv.org/abs/1304.7770

Where to Look for Life on Jupiter's Moon Europa

These images show the trailing hemisphere of Jupiter's moon Europa taken by the Galileo spacecraft at a distance of about 677,000 km. 

The left image shows Europa in approximately true colour and the right image shows Europa in enhanced colour to bring out details. 

The bright feature towards the lower right of the disk is the 45 km diameter crater Pwyll.

CREDIT: NSSDC Photo Gallery

Jupiter's icy moon Europa is thought to be hiding a saltwater ocean beneath its thick outer crust, an exciting prospect for scientists searching for extra-terrestrial life in our solar system.

A fresh look at decade-old observations from NASA's Galileo mission could help researchers pick the ideal spot to probe Europa in the future to get an idea of what's below its surface.

J. Brad Dalton

"We have found the regions where charged electrons and ions striking the surface would have done the most, and the least, chemical processing of materials emplaced at the surface from the interior ocean," J. Brad Dalton of NASA's Jet Propulsion Laboratory, said in a statement.

"That tells us where to look for materials representing the most pristine ocean composition, which would be the best places to target with a lander or study with an orbiter."

Jupiter has the most powerful magnetic field of all the planets in our solar system at nearly 20,000 times the strength of Earth's.

This field traps electrons and other charged particles including ions of sulfur and oxygen spewed from volcanic eruptions on Io, a neighboring Jovian moon.

The particles in this field rush around Jupiter at a rate of about 10 hours per circuit, while Europa, which is about the size of Earth's moon, takes 3.6 days to orbit the planet in the same direction.

And like Earth's moon, Europa has a far side that is always facing away from Jupiter's surface. This means it also has a back side that is constantly being smacked with speeding particles, which takes a toll on the surface chemistry.

By looking at observations from Galileo's near infrared mapping spectrometer, Dalton and colleagues saw that there tended to be more frozen sulphuric acid at parts of Europa that had been more heavily bombarded with electrons and sulfur ions.

"If you are interested in the composition and habitability of the interior ocean, the best places to study would be the parts of the leading hemisphere we have identified as receiving the fewest electrons and having the lowest sulfuric acid concentrations," Dalton said.

The researchers believe these places are the most likely to have chemical compounds that originated from Europa's interior, and are not the result of surface chemical reactions.

"The darkest material, on the trailing hemisphere, is probably the result of externally-driven chemical processing, with little of the original oceanic material intact," Dalton added.

"While investigating the products of surface chemistry driven by charged particles is still interesting from a scientific standpoint, there is a strong push within the community to characterize the contents of the ocean and determine whether it could support life. These kinds of places just might be the windows that allow us to do that."

NASA's Galileo spacecraft was launched in 1989 and finally arrived at Jupiter's system in 1995. It spent eight years circling the solar system's most giant planet before its mission ended in 2003.

The new research was detailed recently in the journal Planetary and Space Science.

NASA Cassini sees precursors to aerosol haze on Titan

NASA's Cassini spacecraft looks toward the night side of Saturn's largest moon and sees sunlight scattering through the periphery of Titan's atmosphere and forming a ring of color. 

Titan's north polar hood can be seen at the top of this view, and a hint of the south polar vortex can be detected at the bottom. 

This view looks toward the Saturn-facing side of Titan (3,200 miles, or 5,150 kilometers across). 

North on Titan is up and rotated 9 degrees to the right. 

Images taken using red, green and blue spectral filters were combined to create this natural colour view. 

The images were acquired with the Cassini spacecraft wide-angle camera on June 6, 2012, at a distance of approximately 134,000 miles (216,000 kilometers) from Titan. 

Image scale is 8 miles (13 kilometers) per pixel. 

Credit: NASA/JPL-Caltech/Space Science Institute

Scientists working with data from NASA's Cassini mission have confirmed the presence of a population of complex hydrocarbons in the upper atmosphere of Saturn's largest moon, Titan, that later evolve into the components that give the moon a distinctive orange-brown haze.

The presence of these complex, ringed hydrocarbons, known as polycyclic aromatic hydrocarbons (PAHs), explains the origin of the aerosol particles found in the lowest haze layer that blankets Titan's surface.

Scientists think these PAH compounds aggregate into larger particles as they drift downward.

"With the huge amount of methane in its atmosphere, Titan smog is like L.A. smog on steroids," said Scott Edgington, Cassini deputy project scientist based at NASA's Jet Propulsion Laboratory.

"These new papers using Cassini data shed light on how the heavy, complex hydrocarbon molecules that make up Titan's smog came to form out of the simpler molecules in the atmosphere. Now that they have been identified, the longevity of Cassini's mission will make it possible to study their variation with Titan seasons."

Of all the bodies in the solar system, Saturn's largest moon, Titan, has the atmosphere most resembling that of Earth.

Like that of our planet, Titan's atmosphere is largely composed of molecular nitrogen. Unlike Earth's atmosphere, however, Titan's contains only small traces of oxygen and water.

Another molecule, methane, plays a similar role to that of water in Earth's atmosphere, and makes up about 2 percent of Titan's atmosphere.

Scientists have speculated that the atmosphere of this moon may resemble that of our planet in its early days, before primitive living organisms enriched it with oxygen via photosynthesis.

When sunlight or highly energetic particles from Saturn's magnetic bubble hit the layers of Titan's atmosphere above about 600 miles (1,000 kilometers), the nitrogen and methane molecules there are broken up.

This results in the formation of massive positive ions and electrons, which trigger a chain of chemical reactions, producing a variety of hydrocarbons—a wide range of which have been detected in Titan's atmosphere.

These reactions eventually lead to the production of carbon-based aerosols, large aggregates of atoms and molecules that are found in the lower layers of the haze that enshrouds Titan, well below 300 miles (500 kilometers).

The process is similar to Earth, where smog starts with sunlight breaking up hydrocarbons that are emitted into the air. The resulting pieces recombine to form more complex molecules.

Aerosols in Titan's lower haze have been studied using data from the descent of the European Space Agency's Huygens probe, which reached the surface in 2005, but their origin remained unclear.

New studies analyzing data from Cassini's visual and infrared mapping spectrometer (VIMS) gathered in July and August 2007 might solve the problem.

One new study of Titan's upper atmosphere in the Astrophysical Journal describes the detection of the PAHs, which are large carbon-based molecules that form from the aggregation of smaller hydrocarbons.

"We can finally confirm that PAHs play a major role in the production of Titan's lower haze, and that the chemical reactions leading to the formation of the haze start high up in the atmosphere," said this paper's lead author Manuel López-Puertas from the Astrophysics Institute of Andalucia in Granada, Spain.

"This finding is surprising: we had long suspected that PAHs and aerosols were linked in Titan's atmosphere, but didn't expect we could prove this with current instruments."

The team of scientists had been studying the emission from various molecules in Titan's atmosphere when they stumbled upon a peculiar feature in the data. One of the characteristic lines in the spectrum—from methane emissions—had a slightly anomalous shape, and the scientists suspected it was hiding something.

This illustration shows the various steps that lead to the formation of the aerosols that make up the haze on Titan, Saturn's largest moon. 

When sunlight or highly energetic particles from Saturn's magnetosphere hit the layers of Titan's atmosphere above about 600 miles (1,000 kilometers), the nitrogen and methane molecules there are broken up. 

This results in the formation of massive positive ions and electrons, which trigger a chain of chemical reactions that produce a variety of hydrocarbons. 

Many of these hydrocarbons have been detected in Titan's atmosphere, including polycyclic aromatic hydrocarbons (PAHs), which are large carbon-based molecules that form from the aggregation of smaller hydrocarbons. 

Some of the PAHs detected in the atmosphere of Titan also contain nitrogen atoms. PAHs are the first step in a sequence of increasingly larger compounds. 

Models show how PAHs can coagulate and form large aggregates, which tend to sink, due to their greater weight, into the lower atmospheric layers. 

The higher densities in Titan's lower atmosphere favor the further growth of these large conglomerates of atoms and molecules. 

These reactions eventually lead to the production of carbon-based aerosols, large aggregates of atoms and molecules that are found in the lower layers of the haze that enshrouds Titan, well below about 300 miles (500 kilometers). Credit: ESA/ATG medialab

Read more of this story here

Planets Found by Kepler Spacecraft Likely Larger Than Thought

The artist's concept depicts Kepler-62f, a super-Earth planet in the habitable zone of a star smaller and cooler than the sun, located about 1,200 light-years from Earth in the constellation Lyra. 

CREDIT: NASA/Ames/JPL-Caltech

A large number of worlds found by NASA's Kepler alien planet-hunting space telescope are probably significantly larger than scientists previously estimated, a new study suggests.

The Kepler Space Telescope has spotted more than 2,700 potential exoplanets since its launch in 2009, and scientists using the Kitt Peak National Observatory Mayall 4-meter telescope have categorized the home stars of many of those planet candidates for the past three years.

In particular, the researchers made detailed follow-up observations of 300 of the stars Kepler found likely to be harboring exoplanets.

"One of the main findings of this initial work is that our observations indicate that most of the stars we observed are slightly larger than previously thought and one quarter of them are at least 35 percent larger," astronomer and leader of the study Mark Everett said in a statement.

"Therefore, any planets orbiting these stars must be larger and hotter as well. By implication, these new results reduce the number of candidate Earth-size planet analogues detected by Kepler."

NASA MSL: Ancient streambed found on surface of Mars

This set of images compares the Link outcrop of rocks on Mars (left) with similar rocks seen on Earth (right). Credit: NASA

Rounded pebbles on the surface of Mars indicate that a stream once flowed on the red planet, according to a new study by a team of scientists from NASA's Curiosity rover mission, including a University of California, Davis, geologist.

The study will be published in the May 31 issue of the journal Science.

Rounded pebbles of this size are known to form only when transported through water over long distances.

They were discovered between the north rim of the planet's Gale Crater and the base of Mount Sharp, a mountain inside the crater.

The finding represents the first on-site evidence of sustained water flows on the Mars landscape, and supports prospects that the planet could once have been able to host life.

As a co-investigator for NASA's Mars Science Laboratory team, UC Davis geologist and study co-author Dawn Sumner played a key role in choosing Gale Crater as the landing site for Curiosity.

Finding the rounded pebbles, which were deposited more than 2 billion years ago, was a matter of landing in the right place, she said.

"The main reason we chose Gale Crater as a landing site was to look at the layered rocks at the base of Mount Sharp, about five miles away," she said.

"We knew there was an alluvial fan in the landing area, a cone-shaped deposit of sediment that requires flowing water to form. These sorts of pebbles are likely because of that environment. So while we didn't choose Gale Crater for this purpose, we were hoping to find something like this."

The finding comes from Curiosity's exploration of the Mars surface during its first 100 sols (102.7 days on Earth), or Martian days.

During that time, the rover traveled about a quarter mile from its landing site, examining multiple outcrops of pebble-rich slabs.

Curiosity took high-resolution images of these pebbles at three locations known as Goulburn, Link and Hottah.

The grain size, roundness and other characteristics of the pebbles led the researchers to conclude they had been transported by water.

Sumner said the discovery involves some of the most basic principles of geology.

The study area, which has been named 'Hottah', is by all accounts the remains of sediments from the bottom of an ancient stream, which had a relatively strong current. Credit: Malin Space Science Systems

"On the first day of my sedimentary class, I have the students measure grain size and the rounding," Sumner said. "It's simple, and it's important."

Sumner's work in South Africa and Australia studying signs of past microbial life in rocks and her work on living microbial communities in Antarctica helped land her the spot on the Mars Science Laboratory team.

NASA recognized her skills could be critical to the mission's goal: to determine whether there ever could have been life on Mars.

As part of the MSL team, Sumner helped coordinate the first scientific interpretations of what was seen during Curiosity's first few days on Mars, helps direct the rover, via computer, to shoot photographs of the planet, and continues to work on the mission from UC Davis.

NASA Mars Rover Curiosity at 'Cumberland'

NASA's Mars rover Curiosity used its front left Hazard-Avoidance Camera for this image of the rover's arm over the drilling target "Cumberland" during the 275th Martian day, or sol, of the rover's work on Mars (May 15, 2013).

The rover team plans to use Curiosity's drill to collect a powdered sample from the interior of the rock for analysis by laboratory instruments inside the rover. 

This is the mission's second rock-drilling target.

The rover drove from its position beside the first drilling target, "John Klein," to its position beside Cumberland with drives of 121 inches (308 centimeters) on Sol 273 (May 13) and 26.6 inches (67.5 centimeters) on Sol 275. Curiosity's total odometry on Mars is now 2,385 feet (727 meters).

Image credit: NASA/JPL-Caltech

NASA Spitzer Image: Galaxy's Ring of Fire

How many rings do you see in this new image of the galaxy Messier 94, also known as NGC 4736? 

While at first glance one might see a number of them, astronomers believe there is just one. 

This image was captured in infrared light by NASA's Spitzer Space Telescope. 

Credit: NASA/JPL-Caltech

The singer Johnny Cash may have preferred this galaxy's burning ring of fire to the one he sang about falling into in his popular song.

The "starburst ring" seen at centre in red and yellow hues is not the product of love, as in the song, but is instead a frenetic region of star formation.

The galaxy, a spiral beauty called Messier 94, is located about 17 million light-years away. In this image from NASA's Spitzer Space Telescope, infrared light is represented in different colours, with blue having the shortest wavelengths and red, the longest.

Starburst rings like this can often be triggered by gravitational encounters with other galaxies but, in this case, may have instead been caused by the galaxy's oval shape.

Gas in the ring is being converted into hot, young stars, which then warm the dust, causing it to glow with infrared light.

The outer, faint blue ring around the galaxy might be an optical illusion. Astronomers think that two separate spiral arms appear as a single unbroken ring when viewed from our position in space.

NASA Cassini Image captures Enceladus' Plume

Credit: NASA/JPL-Caltech/Space Science Institute

Like a proud peacock displaying its tail, Enceladus shows off its beautiful plume to the Cassini spacecraft's cameras.

Enceladus (313 miles, or 504 kilometers across) is seen here illuminated by light reflected off Saturn.

This view looks toward the Saturn-facing side of Enceladus.

North on Enceladus is up and rotated 45 degrees to the right.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 18, 2013.

The view was acquired at a distance of approximately 483,000 miles (777,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 173 degrees. Image scale is 3 miles (5 kilometers) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency (ISA). 

NASA Voyager-1: Public Invited to Fly along

The public will be able to fly along with NASA's Voyager spacecraft as the twin probes head towards interstellar space, which is the space between stars. 

As indicated in this artist's concept, a regularly updated gauge using data from the two spacecraft will indicate the levels of particles that originate from far outside our solar system and those that originate from inside our solar bubble. 

Those are two of the three signs scientists expect to see in interstellar space. 

The other sign is a change in the direction of the magnetic field. 

Credit: NASA/JPL-Caltech

A gauge on the Voyager home page, tracks levels of two of the three key signs scientists believe will appear when the spacecraft leave our solar neighborhood and enter interstellar space.

When the three signs are verified, scientists will know that one of the Voyagers has hurtled beyond the magnetic bubble the sun blows around itself, which is known as the heliosphere.

The gauge indicates the level of fast-moving charged particles, mainly protons, originating from far outside the heliosphere, and the level of slower-moving charged particles, also mainly protons, from inside the heliosphere.

If the level of outside particles jumps dramatically and the level of inside particles drops precipitously, and these two levels hold steady, that means one of the spacecraft is closing in on the edge of interstellar space. These data are updated every six hours.

Scientists then need only see a change in the direction of the magnetic field to confirm that the spacecraft has sailed beyond the breath of the solar wind and finally arrived into the vast cosmic ocean between stars.

The direction of the magnetic field, however, requires periodic instrument calibrations and complicated analyses. These analyses typically take a few months to return after the charged particle data are received on Earth.

Voyager 1

VOYAGER-1
Voyager 1, the most distant human-made spacecraft, appears to have reached this last region before interstellar space, which scientists have called "the magnetic highway." Inside particles are zooming out and outside particles are zooming in.

However, Voyager 1 has not yet seen a change in the direction of the magnetic field, so the consensus among the Voyager team is that it has not yet left the heliosphere.

Voyager-2

VOYAGER-2
Voyager-2, the longest-operating spacecraft, but not as distant as Voyager 1, does not yet appear to have reached the magnetic highway, though it has recently seen some modest drops of the inside particle level.

NASA's Eyes on the Solar System program, a Web-based, video-game-like tool to journey with NASA's spacecraft through the solar system, has added a Voyager module that takes viewers along for a ride with Voyager 1 as it explores the outer limits of the heliosphere.

Time has been sped up to show one day per second. Rolls and other maneuvers are incorporated into the program, based on actual spacecraft navigation data. The charged particle data are also shown.

Visit that module HERE

The Voyager spacecraft were built and continue to be operated by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Caltech manages JPL for NASA.

The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.

More information about the Voyager spacecraft here.

Windows Into Jupiter's moon Europa's Interior

This graphic of Jupiter's moon Europa maps a relationship between the amount of energy deposited onto the moon from charged-particle bombardment and the chemical contents of ice deposits on the surface in five areas of the moon (labeled A through E). 

Credit: NASA/JPL-Caltech/Univ. of Ariz./JHUAPL/Univ. of Colo.

The surface of Jupiter's moon Europa exposes material churned up from inside the moon and also material resulting from matter and energy coming from above.

If you want to learn about the deep saltwater ocean beneath this unusual world's icy shell -- as many people do, certainly those who are interested in possible extraterrestrial life -- you might target your investigation of the surface.

New analysis of observations made more than a decade ago by NASA's Galileo mission to Jupiter helps identify the deposits that have emanated from 'below' the surface rather than those deposited 'on' the surface.

In particular the report examines Sulphuric Acid Hydrate production on Europa's surface.

J. Brad Dalton

"We have found the regions where charged electrons and ions striking the surface would have done the most, and the least, chemical processing of materials emplaced at the surface from the interior ocean," said J. Brad Dalton of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead author of the report published recently in the journal Planetary and Space Science.

"That tells us where to look for materials representing the most pristine ocean composition, which would be the best places to target with a lander or study with an orbiter."

Europa is about the size of Earth's moon and, like our moon, keeps the same side toward the planet it orbits.

Picture a car driving in circles around a mountain with its left-side windows always facing the mountain.

Europa's orbit around Jupiter is filled with charged, energetic particles tied to Jupiter's powerful magnetic field.

Jupiter's Moon Io

Besides electrons, these particles include ions of sulphur and oxygen originating from volcanic eruptions on Io, a neighbouring Jupiter moon.

The magnetic field carrying these energetic particles sweeps around Jupiter faster than Europa orbits Jupiter, in the same direction: about 10 hours per circuit for the magnetic field versus about 3.6 days for Europa's orbit.

So, instead of our mountain-circling car getting bugs on the front windshield, the bugs are plastered on the back of the car by a "wind" from behind going nearly nine times faster than the car.

Europa has a "leading hemisphere" in front and a "trailing hemisphere" in back.

NASA's Galileo Satellite

Earlier studies had found more sulphuric acid hydrate being produced towards the center of the trailing hemisphere than elsewhere on Europa's surface, interpreted as resulting from chemistry driven by sulphur ions bombarding the icy surface.

Surface deposits in these areas are most likely to preserve the original chemical compounds that erupted from the interior.

Dalton suggests that any future spacecraft missions to Europa should target these deposits for study from orbit, or even attempt to land there.

Dalton stated "While investigating the products of surface chemistry driven by charged particles is still interesting from a scientific standpoint, there is a strong push within the community to characterize the contents of the ocean and determine whether it could support life. These kinds of places just might be the windows that allow us to do that."

NASA Spitzer Image: Heavenly Valentine

Generations of stars can be seen in this infrared portrait from NASA's Spitzer Space Telescope.

In this wispy star-forming region, called W5, the oldest stars can be seen as blue dots in the centers of the two hollow cavities (other blue dots are background and foreground stars not associated with the region).

Younger stars line the rims of the cavities, and some can be seen as pink dots at the tips of the elephant-trunk-like pillars. 

The white knotty areas are where the youngest stars are forming. Red shows heated dust that pervades the region's cavities, while green highlights dense clouds. 

Image Credit: NASA/JPL-Caltech/Harvard-Smithsonian