Tropically Speaking, NASA Investigates Precipitation Shapes, Sizes for Severity

Rain drops are fat and snowflakes are fluffy, but why does it matter in terms of predicting severe storms?

We've all seen fat rain drops, skinny rain drops, round hailstones, fluffy snowflakes and even ice needles. This summer, NASA researchers are going to get a look at just how much these shapes influence severe storm weather. To do it, they'll have to look inside the guts of some of the world's fiercest storms. NASA recently assembled a team of hurricane scientists from across the country to carry out high-altitude-aircraft surveillance to explore in detail how storms form, intensify and dissipate.

Earth scientists and engineers at NASA's Marshall Space Flight Center in Huntsville, Ala., have redesigned one of their instruments, the Advanced Microwave Precipitation Radiometer, or AMPR, to better observe the different shapes of precipitation. In August and September, AMPR will fly at an altitude of 60,000 feet over the Gulf of Mexico and Atlantic Ocean. It will sit in the bomb bay of a WB-57 airplane, which is based at the NASA Johnson Space Center's Ellington Field in Houston.

AMPR will sit in the bomb bay of a WB-57 airplane, where it will scan the surfaces below to measure both how hard it’s raining and the type of precipitation being produced by a storm. (NASA/JSC)

During these flights, AMPR researchers will test a new build -- the instrument is an upgraded version of the original AMPR built at NASA Marshall in the early 1990s -- and use it to participate in NASA's upcoming hurricane study, the Genesis and Rapid Intensification Processes field campaign, better known as GRIP. The campaign involves three planes mounted with 14 different instruments, including AMPR. The instruments will all work together to create the most complete view of a hurricane to date.

Researchers hope the hurricane campaign will help them answer some of nature's most perplexing questions. As tropical storms grow, they produce massive amounts of rain -- a key element in the development of full-scale hurricanes. Scientists will use AMPR along with the other instruments, such as data from the Tropical Rainfall Measuring Mission or TRMM satellite, to figure out just how hard it's raining inside these ferocious storms, and how much of that rain is associated with the production of ice during intensification.

"If you don't know how hard it's raining or where the rain is forming in the atmosphere, you don't know hurricanes," said Dr. Walt Petersen, AMPR principle investigator and Marshall Center earth scientist. "AMPR provides us an opportunity to see their precipitation structure by using an instrument like those currently flying on, for example, the TRMM and Aqua satellites in space."

That's because AMPR doesn't just give scientists new information about hurricanes. The instrument also enables them to test equipment currently in space. Every day, numerous weather satellites orbit Earth to measure the rainfall rate of storms across the globe. They work much like AMPR except over much larger scales. Because they're so far above the Earth and moving so fast, they can take only one measurement every few miles along their track. Scientists can correct for such coarse measurements, but to do so they need highly accurate data. AMPR can take several measurements per mile, giving scientists the data they need to verify that weather satellites continue to provide accurate data.

Crashing waves in the deep ocean can generate enough energy to create a seismic "hum." (Bruce Molnia/U.S. Geological Survey)

"It's like the pixels in your computer screen," Petersen said. "When satellites take measurements, they have really big pixels, and we might lose some of the finer details of what's happening on the ground. AMPR has much smaller pixels, much higher resolution, and allows us to see a much clearer picture. It's a part of our arsenal to make sure what we're measuring from space makes sense. We'd hate to send something up and not have it accurately measure what's happening on the ground."

That information translates into better predictions of hurricane track and intensity -- how hard it's going to rain in a certain area when a hurricane hits, for example, aiding in early flood warnings.

AMPR doesn't just measure how hard rain falls. Within the last several years, the AMPR team has worked vigorously to upgrade the instrument. These upgrades will enable AMPR to more accurately detect what kind of precipitation is in the storm. By identifying the shape of the precipitation, AMPR may present scientists with recognizable signatures that define different types of precipitation. For example, varying combinations of fat or skinny rain drops, snow, ice or hail distributed throughout the depth of the storm will produce different brightness temperatures when viewed at different angles. A storm may develop and behave differently depending on these variations.

Engineers packed the 380-pound AMPR payload with a delicate set of instruments and computer hardware. AMPR gathers data by measuring the amount of microwave radiation rising from the surface beneath -- often the ocean. Because rain water is a better emitter of microwave radiation than ocean water, the radiation measured from rainfall is actually greater during a big storm. This measurement is converted to a "brightness temperature," which correlates to how much radiation is being generated. The more rain, the higher the brightness temperature.

Alternatively, if a hurricane's clouds are full of ice or hail, as they usually are, much of the microwave radiation is scattered away. The corresponding brightness temperature is much lower than the anticipated surface measurement. Scientists can use those changes to determine how hard it's raining inside a storm or how much ice a given storm might contain.

"Whether rain drops are fat or skinny, and whether ice is round or bumpy, these factors are critical when we're trying to estimate rainfall rates," Petersen explained. "Because of air drag, the rate at which these precipitation particles fall through the air depends on their thickness or shape. A fat rain drop falls more slowly than a hail stone of the same size, for example -- that factor enables you to determine rainfall rate."

This image over Southern Brazil, taken from the space shuttle by an astronaut in February 1984 and shows a mixture of cold and warm clouds. (NASA/JSC)

After the GRIP experiment ends in September, Petersen and his team will unload the data and begin analyzing it, adding their findings to the increasingly large body of hurricane knowledge.

"The GRIP experiment will give us information about how a hurricane circulates and how it intensifies. Basically we have a bunch of theories about the role of precipitation in hurricanes, and we need to test them. That's where instruments like AMPR come in."

After this summer’s hurricane study, AMPR will continue to fly in storm campaigns. It's already scheduled for a major joint NASA and U.S. Department of Energy study in April 2011 to support the Global Precipitation Measurement

Petersen loves the challenge. Storms have fascinated him ever since his junior year of high school, when lightning struck just inches away from him while he was at a drive-in movie.

"The thing that excites me is looking inside a storm that we can't fly into," he said. "We can't fly inside these big storms because they're just too nasty. The only way to get information about what's going on inside is to do what AMPR does.

"Being able to look at the guts of a storm and figure out what's going on, that's the key thing for me," he added.

With any luck, AMPR's look into hurricanes will put scientists one step closer to predicting some of the world's fiercest storms.

For more information visit http://www.nasa.gov/mission_pages/hurricanes/missions/grip/news/ampr.html

Ping-Pong Balls to Float Crew Capsule Simulator

If ping-pong balls can float a sunken boat, they should be able to keep an uncrewed space capsule simulator from sinking.

Right?

That's what a team of summer students and engineers think at NASA's Langley Research Center in Hampton, Va. Langley is fabricating a proposed design of an astronaut crew module simulator for uncrewed flight-testing as part of the agency's effort to build a vehicle to replace the space shuttle.

The Orion crew exploration vehicle is the nation's next generation spacecraft designed to carry up to four astronauts to low Earth orbit and beyond.

Orion's first suborbital flight test will launch to 400,000 feet, or 75 miles above Earth. Because the crew module will not be pressurized during the test, it will not have the buoyancy of a pressurized spacecraft. This puts the simulated crew module at risk of sinking to the bottom of the Atlantic Ocean after splashdown.

To save the valuable test article for analysis and possible reuse, Langley called on a team of creative minds for a solution.

NASA Langley students gather around the crew module mockup that they propose to keep afloat with ping-pong balls after it splashes down. From left, front row: Edward Tillistrand, Brice Collamer, Patrick Cragg, Caroline Kirk and Kurian Thomas. In the capsule, from left; Joseph Randall Hunt, Heather Blount and Victor Stewart. Credit: NASA/Sean Smith

And as it turned out, inexpensive, lightweight ping-pong balls provided the answer. Langley engineer John DiNonno proposed the idea, and the Orion Flight Test Office told the team to study it.

The idea quickly became "very plausible," said student Caroline Kirk.

Way to go

"At first we didn't really realize that we were going to get so far in proving that it would be possible," said Kirk, a Suffolk, Va., native attending Virginia Tech as an aerospace engineering major. "But when we thought about everything logically, it just seemed like ping-pong balls were the way to go."

She and a team of seven other students worked the project in Langley's Mechanical Systems Branch, where they were assigned for the summer.

DiNonno got the idea from a Discovery Channel program about raising a sunken boat using 27,000 ping-pong balls.

Engineer David Covington said that when DiNonno suggested the ping-pong ball idea, "I just laughed. Not a 'what are you thinking' kind of laugh, but more of a 'that's the most awesome thing I've heard in a long time' laugh. I asked him 'are you serious?' and he said 'yeah, we're authorized to do a four-week study.' So we went straight to work."

Ensuring the outcome would be relatively low-cost was a top priority, said DiNonno.

"Recovering the capsule was not a requirement, but it was a desire," he said. "So there wasn't going to be a lot of investment in it."

Testing process

The students divided the tasks needed to determine if the idea was feasible, each becoming a "principal investigator" for a specific area.

They tested ping-pong balls of varying quality, much the way spacecraft hardware is tested. They studied how the balls would react to the near-vacuum at the edge of space. Using buoyancy tests, they determined how well the balls would float.

The students also subjected the ping-pong balls to mechanical loads using a hydraulic press, and heated them to see how they would react to the high temperatures of descent into the Earth's atmosphere. And they performed electrostatic discharge tests to determine if the balls would produce a static charge that could disrupt the space capsule's electronics.

Ping-Pong Ball Facts

›› Ping-pong balls are made of celluloid, which is processed cotton.
›› Each ping-pong ball weighs less than an ounce (2.7 grams) and is roughly 1.5 inches (38 - 40 mm) in diameter.
›› Ping-pong ball quality is rated from zero to three stars.

Credit: Microsoft

The ping-pong balls passed all the challenges, said Heather Blount, a materials science engineering student at Virginia Tech.

"Through all our testing and calculations, we figured out that it could be a safe and viable option," said Blount, of Yorktown, Va.

Keeping the crew module afloat would take at least 150,000 ping-pong balls, the students estimate, at a retail price of 50 cents or less each -- a fraction of the cost of traditional options. The students hope to reduce the cost through a bulk purchase.

If the flight test is approved, the ping-pong ball concept would still need to be vetted with the flight test team and reviewed by NASA senior management. If implemented, the ping-pong balls probably will be put into netted bags and secured inside the crew module just prior to launch. They would virtually fill the available space inside the uncrewed capsule.

Then, when the unsealed capsule splashes down, the buoyancy of the ping-pong balls will offset the weight of incoming water and it will float instead of sink.

The ping-pong balls also will reduce the volume of air that needs to be vented from the capsule during ascent - as well as drawn in during descent - as the capsule travels through significant changes in atmospheric pressure.

'Awesome' students

Approval of the flight test, as well as a launch date, has yet to be determined. "Even if it is not used, it's an idea that's out there that someone else could use," said Langley engineer Amanda Cutright, a student mentor.

Cutright said she has been enthused by the students.

"It's awesome working with them," she said. "They bring a different perspective. I've been really impressed with how quickly they pick up new ideas and new technology. It seems each team of students that we mentor learns quicker and is able to provide creative ideas."

Yammer

The ping-pong ball team has been using a social media tool called Yammer to communicate with each other, share files, links, work status, questions, and solutions.

"Yammer has been a great tool to communicate with the interns," said Brendan Shaughnessy, an engineer in the Mechanical Systems Branch. "They can post updates on their work or links to websites they found. I can also let them all know about something I need them to do or that I've done in one quick message."

To join NASA's Yammer site, you must have an email address that ends in nasa.gov.

The Orion FTA Students site is open to anyone with a NASA Yammer account.

Credit: Yammer.com

Kirk said the ping-pong ball project has been a unique experience. At school, she said, "we do lab experiments but nothing similar to this at all. Being able to develop an experiment that will be used for space flight tests is an opportunity of a lifetime."

NASA employees and contractors involved in the project include engineers Amanda Cutright; Brendan Shaughnessy, Analytical Services and Materials Inc.; David Covington, ATK Space Systems Inc.; and John DiNonno, all of the Mechanical Systems Branch.

Student team members:

Brice Collamer, Virginia Tech, Langley Aerospace Research Summer Scholars (LARSS) program
→ Principal investigator for electrostatic discharge tests
Patrick Cragg, Princeton University, DEVELOP program
→ Principal investigator for further testing and research
Kurian Thomas, University of Virginia, DEVELOP program
→ Principal investigator for loading tests and cost analysis
Caroline Kirk, Virginia Tech, LARSS
→ Co-principal investigator for vacuum oven tests
Joseph Randall Hunt, Western Carolina University, Undergraduate Student Research Program
→ Principal investigator for packing efficiency tests and operations concerns
Heather Blount, Virginia Tech, LARSS
→ Co-principal investigator for vacuum oven tests
Edward Tillistrand, University of Virginia, DEVELOP program
→ Principal investigator for buoyancy tests and quantity analysis
Victor Stewart, Virginia Tech, Cooperative Education Program
→ Principal investigator for support and review of experiment work

For more information visit http://www.nasa.gov/mission_pages/constellation/orion/orionfta-pingpong.html

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IBEX Spacecraft Finds Discoveries Close to Home

Imagine floating 35,000 miles above the sunny side of Earth. Our home planet gleams below, a majestic whorl of color and texture. All seems calm around you. With no satellites or space debris to dodge, you can just relax and enjoy the black emptiness of space.

But looks can be deceiving.

In reality, you've unknowingly jumped into an invisible mosh pit of electromagnetic mayhem — the place in space where a supersonic "wind" of charged particles from the Sun crashes head-on into the protective magnetic bubble that surrounds our planet. Traveling at a million miles per hour, the solar wind's protons and electrons sense Earth's magnetosphere too late to flow smoothly around it. Instead, they're shocked, heated, and slowed almost to a stop as they pile up along its outer boundary, the magnetopause, before getting diverted sideways.

Space physicists have had a general sense of these dynamic goings-on for decades. But it wasn't until the advent of the Interstellar Boundary Explorer or IBEX, a NASA spacecraft launched in October 2008, that they've been able to see what the human eye cannot: the first-ever images of this electromagnetic crash scene. They can now witness how some of the solar wind's charged particles are being neutralized by gas escaping from Earth's atmosphere.

A New Way to See Atoms

IBEX wasn't designed to keep tabs on Earth's magnetosphere. Instead, its job is to map interactions occurring far beyond the planets, 8 to 10 billion miles away, where the Sun's own magnetic bubble, the heliosphere, meets interstellar space.

IBEX found that Energetic Neutral Atoms, or ENAs, are coming from a region just outside Earth's magnetopause where nearly stationary protons from the solar wind interact with the tenuous cloud of hydrogen atoms in Earth's exosphere. Credit: NASA/Goddard Space Flight Center

Only two spacecraft, Voyagers 1 and 2, have ventured far enough to probe this region directly. IBEX, which travels in a looping, 8-day-long orbit around Earth, stays much closer to home, but it carries a pair of detectors that can observe the interaction region from afar.

Here's how: When fast-moving protons in the solar wind reach the edge of the heliosphere, they sometimes grab electrons from the slower-moving interstellar atoms around them, like batons getting passed between relay runners. This charge exchange creates electrically neutral hydrogen atoms that are no longer controlled by magnetic fields. Suddenly, they're free to go wherever they want — and because they're still moving fast, they quickly zip away from the interstellar boundary in all directions.

> Download video

This animation shows a neutral solar particle's path leaving the Sun, following the magnetic field lines out to the Heliosheath. The solar particle hits a hydrogen atom, stealing it's electron and we follow it until we see it hit one of IBEXs detectors. Credit: NASA/Goddard Space Flight Center

Some of these "energetic neutral atoms," or ENAs, zip past Earth, where they're recorded by IBEX. Its two detectors don't take pictures with conventional optics. Instead, they record the number and energy of atoms arriving from small spots of sky about 7 degrees across (the apparent size of a tennis ball held at arm's length). Because its spin axis always points at the Sun, the spacecraft slowly turns throughout Earth's orbit and its detectors scan overlapping strips that create a complete 360 degrees map every six months.

A Collision Zone Near Earth

Because IBEX is orbiting Earth, it also has a front-row seat for observing the chaotic pileup of solar-wind particles occurring along the "nose" of Earth's magnetopause, about 35,000 miles out. ENAs are created there too, as solar-wind protons wrest electrons from hydrogen atoms in the outermost vestiges of our atmosphere, the exosphere.

Other spacecraft have attempted to measure the density of the dayside exosphere, without much success. NASA's Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft probably detected ENAs from this region a decade ago, but its detectors didn't have the sensitivity to pinpoint or measure the source.

Now, thanks to IBEX, we know just how tenuous the outer exosphere really is. "Where the interaction is strongest, there are only about eight hydrogen atoms per cubic centimeter," explains Stephen A. Fuselier, the Lockheed Martin Space Systems researcher who led the mapping effort. His team's results appear in the July 8 issue of Geophysical Research Letters.

The key observations were made in March and April 2009, when IBEX was located far from Earth — about halfway to the Moon's orbit — and its detectors could scan the region directly in front of the magnetopause. During some of the March observations, the European Space Agency's Cluster 3 spacecraft was positioned just in front of the magnetopause, where it measured the number of deflected solar-wind protons directly. "Cluster played a very important role in this study," Fuselier explains. "It was in the right place at the right time."

Artist concept of the IBEX satellite. Credit: NASA/Goddard Space Flight Center

The new IBEX maps show that the ENAs thin out at locations away from the point of peak intensity. This falloff makes sense, Fuselier says, because Earth's magnetopause isn't spherical. Instead, it has a teardrop shape that's closest to Earth at its nose but farther away everywhere else. So at locations well away from the magnetopause's centerline, even fewer of the exosphere's hydrogen atoms are hanging around to interact with the solar wind. "No exosphere, no ENAs," he explains.

A Versatile Spacecraft

Since its launch, IBEX has also scanned another nearby world, with surprising results. The moon has no atmosphere or magnetosphere, so the solar wind slams unimpeded into its desolate surface. Most of those particles get absorbed by lunar dust. In fact, space visionaries wonder if the moon's rubbly surface has captured enough helium-3, an isotope present in tiny amounts in the Sun's outflow, to serve as a fuel for future explorers.

Yet cosmic chemists have long thought that some solar-wind protons must be bouncing off the lunar surface, becoming ENAs through charge exchange as they do. So does the moon glow in IBEX's scans? Indeed it does, says David J. McComas of Southwest Research Institute in San Antonio, Texas, who serves as the mission's Principal Investigator.

In a report published last year in Geophysical Research Letters, McComas and other researchers conclude that about 10 percent of the solar-wind particles striking the Moon escape to space as ENAs detectable by IBEX. That amounts to roughly 150 tons of recycled hydrogen atoms per year.

Meanwhile, the squat, eight-sided spacecraft continues its primary task of mapping the interactions between the outermost heliosphere and the interstellar medium that lies beyond. McComas and his team are especially eager to learn more about the mysterious and unexpected "ribbon" of ENAs that turned up in the spacecraft's initial all-sky map.

At NASA's Goddard Space Flight Center in Greenbelt, Md., IBEX Mission Scientist Robert MacDowall says the spacecraft should be able to continue its observations through at least 2012. "We weren't sure those heliospheric interactions would vary with time, but they do," he explains, "and it's great that IBEX will be able to record them for years to come."

For more information visit http://www.nasa.gov/mission_pages/ibex/em-crash.html

Fermi Detects 'Shocking' Surprise from Supernova's Little Cousin

Astronomers using NASA's Fermi Gamma-ray Space Telescope have detected gamma-rays from a nova for the first time, a finding that stunned observers and theorists alike. The discovery overturns the notion that novae explosions lack the power to emit such high-energy radiation.

A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear explosion.

"In human terms, this was an immensely powerful eruption, equivalent to about 1,000 times the energy emitted by the sun every year," said Elizabeth Hays, a Fermi deputy project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "But compared to other cosmic events Fermi sees, it was quite modest. We're amazed that Fermi detected it so strongly."

Fermi's Large Area Telescope saw no sign of a nova in 19 days of data prior to March 10 (left), but the eruption is obvious in data from the following 19 days (right). The images show the rate of gamma rays with energies greater than 100 million electron volts (100 MeV); brighter colors indicate higher rates. Credit: NASA/DOE/Fermi LAT Collaboration

Gamma rays are the most energetic form of light, and Fermi's Large Area Telescope (LAT) detected the nova for 15 days. Scientists believe the emission arose as a million-mile-per-hour shock wave raced from the site of the explosion.

A paper detailing the discovery will appear in the Aug. 13 edition of the journal Science.

The story opened in Japan during the predawn hours of March 11, when amateur astronomers Koichi Nishiyama and Fujio Kabashima in Miyaki-cho, Saga Prefecture, imaged a dramatic change in the brightness of a star in the constellation Cygnus. They realized that the star, known as V407 Cyg, was 10 times brighter than in an image they had taken three days earlier.

The team relayed the nova discovery to Hiroyuki Maehara at Kyoto University, who notified astronomers around the world for follow-up observations. Before this notice became widely available, the outburst was independently reported by three other Japanese amateurs: Tadashi Kojima, Tsumagoi-mura Agatsuma-gun, Gunma prefecture; Kazuo Sakaniwa, Higashichikuma-gun, Nagano prefecture; and Akihiko Tago, Tsuyama-shi, Okayama prefecture.

Japanese amateur astronomers discovered Nova Cygni 2010 in an image taken at 19:08 UT on March 10 (4:08 a.m. Japan Standard Time, March 11). The erupting star (circled) was 10 times brighter than in an image taken several days earlier. The nova reached a peak brightness of magnitude 6.9, just below the threshold of naked-eye visibility. Credit: K. Nishiyama and F. Kabashima/H. Maehara, Kyoto Univ.

On March 13, Goddard's Davide Donato was on-duty as the LAT "flare advocate," a scientist who monitors the daily data downloads for sources of potential interest, when he noticed a significant detection in Cygnus. But linking this source to the nova would take several days, in part because key members of the Fermi team were in Paris for a meeting of the LAT scientific collaboration.

"This region is close to the galactic plane, which packs together many types of gamma-ray sources -- pulsars, supernova remnants, and others in our own galaxy, plus active galaxies beyond them," Donato said. "If the nova had occurred elsewhere in the sky, figuring out the connection would have been easier."

The LAT team began a concerted effort to identify the mystery source over the following days. On March 17, the researchers decided to obtain a "target-of-opportunity" observation using NASA's Swift satellite -- only to find that Swift was already observing the same spot.

"At that point, I knew Swift was targeting V407 Cyg, but I didn't know why," said Teddy Cheung, an astrophysicist at the Naval Research Laboratory (NRL) in Washington, D.C., and the lead author of the study. Examining the Swift data, Cheung saw no additional X-ray sources that could account for what Fermi's LAT was seeing.

V407 Cyg had to be it.

Half an hour later, Cheung learned from other members of the LAT team that the system had undergone a nova outburst, which was the reason the Swift observations had been triggered. "When we looked closer, we found that the LAT had detected the first gamma rays at about the same time as the nova's discovery," he said.

This image from Steve O'Connor in St. Georges, Bermuda, shows the nova (red star, center) on March 17, about a week into the eruption. Credit: Steve O'Connor

V407 Cyg lies 9,000 light-years away. The system is a so-called symbiotic binary containing a compact white dwarf and a red giant star about 500 times the size of the sun.

"The red giant is so swollen that its outermost atmosphere is just leaking away into space," said Adam Hill at Joseph Fourier University in Grenoble, France. The phenomenon is similar to the solar wind produced by the sun, but the flow is much stronger. "Each decade, the red giant sheds enough hydrogen gas to equal the mass of Earth," he added.

The white dwarf intercepts and captures some of this gas, which accumulates on its surface. As the gas piles on for decades to centuries, it eventually becomes hot and dense enough to fuse into helium. This energy-producing process triggers a runaway reaction that explodes the accumulated gas.

The white dwarf itself, however, remains intact.

The blast created a hot, dense expanding shell called a shock front, composed of high-speed particles, ionized gas and magnetic fields. According to an early spectrum obtained by Christian Buil at Castanet Tolosan Observatory, France, the nova's shock wave expanded at 7 million miles per hour -- or nearly 1 percent the speed of light.

Watch V407 Cyg go nova! Gamma rays (magenta) arise when accelerated particles in the explosion's shock wave crash into the red giant's stellar wind. Credit: NASA/Goddard Space Flight Center/ Conceptual Image Lab.

The magnetic fields trapped particles within the shell and whipped them up to tremendous energies. Before they could escape, the particles had reached velocities near the speed of light. Scientists say that the gamma rays likely resulted when these accelerated particles smashed into the red giant's wind.

"We know that the remnants of much more powerful supernova explosions can trap and accelerate particles like this, but no one suspected that the magnetic fields in novae were strong enough to do it as well," said NRL's Soebur Razzaque.

Supernovae remnants endure for 100,000 years and affect regions of space thousands of light-years across.

Kent Wood at NRL compares astronomical studies of supernova remnants to looking at static images in a photo album. "It takes thousands of years for supernova remnants to evolve, but with this nova we've watched the same kinds of changes over just a few days," he said. "We've gone from a photo album to a time-lapse movie."

For more information visit http://www.nasa.gov/mission_pages/GLAST/news/shocking-nova.html

Saving the Samples

People who lived through extended power outages know that one of the first concerns is the food in the freezer. Short of eating all the ice cream you can, there is little to do to save perishable items. The International Space Station (ISS) experienced a similar power outage on orbit this week. Only ISS freezers hold science instead of food.

On Saturday, July 31, an ISS system pump failed due to an electrical current spike, shutting down half the ISS cooling system. The crew’s first concern was ensuring a safe and stable environment. Saving the science onboard was a follow-up goal, as the pump failure also impaired the Low Temperature Loop (LTL) in the Japanese Experiment Module (JEM). This meant the ISS crew had to shut down one of the onboard science freezers, the Minus Eighty-Degree Laboratory Freezer for ISS (MELFI).

The ISS perishable experiment samples in danger of thawing included:

• Nutrition: Studies changes in human physiology during long-term space flight.
• HydroTropi: Examines a cucumber model plant and changes in root structure and direction of growth due to gravity and other stimuli.
• SOLO: Studies the mechanisms of fluid and salt retention in the body during space flight.

The ISS crew and NASA Cold Stowage team worked together to save the samples, preventing the loss of scientific knowledge and international investment. John Bartlett, resident Marshall Space Flight Center (MSFC) Payload Operations Director, was on consol in MSFC at the time of the transfers and commented, “Two MELFIs operating on orbit has always been a contingency plan for a failed unit on board.” MELFI 2 was not impacted, as it resides in the U.S. Laboratory and not JEM, so the ground team decided to relocate MELFI 1 samples to MELFI 2.

View of Shannon Walker as she works to replace a dewar tray filled with samples, into the Minus Eighty Laboratory Freezer for ISS (MELFI-1) in the Kibo laboratory during Expedition 24. In the larger image, Tracy Caldwell-Dyson can be seen assisting. Image credit: NASA

Instructions to locate and transfer the science in MELFI 1 were sent to the POIC, who called the instructions up to the ISS crew. Mr. Bartlett commended the effort, "I was extremely pleased with the quick response by the MELFI/COLD Team... for them to provide such a well structured, two phased retrieval and stow plan in that short of a time was outstanding!"

The crew performed the transfer in two stages. They used the Double Coldbag (DCB) and two -32 Degrees Celcius Icepac Belts for deep frozen samples. The crew then used a coldbag with +4 Degrees Celcius Ice Bricks to transfer the remaining frozen samples to MELFI 2.

Thanks to the quick actions and teamwork between the ISS crew and ground support, all samples now safely reside in MELFI 2. The crew may not have been working with ice cream in their freezers, but they certainly deserve a celebratory ice cream social with their teammates when they return home to Earth!

For more information visit http://www.nasa.gov/mission_pages/station/science/save_samples.html

Star Wars Meets UPS as Robonaut Packed for Space

Getting into space isn't necessarily easy for astronauts, and it's not much easier for a robotic astronaut, either.

Cocooned inside an aluminum frame and foam blocks cut out to its shape, Robonaut 2, or R2, is heading to the International Space Station inside the Permanent Multipurpose Module in space shuttle Discovery's payload bay as part of the STS-133 mission.

Once in place inside the station, R2, with its humanlike hands and arms and stereo vision, is expected to perform some of the repetitive or more mundane functions inside the orbiting laboratory to free astronauts for more complicated tasks and experiments. It could one day also go along on spacewalks.

Making sure the first humanoid robot to head into space still works when it gets there has been the focus of workers at NASA's Kennedy and Johnson space centers. Engineers and technicians with decades of experience among them packing for space have spent the last few months devising a plan to secure the 330-pound machine against the fierce vibrations and intense gravity forces during launch.

Robonaut2 is designed as an assistant to astronauts on the International Space Station. But to to get there, it will need some assistance of its own from engineers and technicians on Earth. Photo credit: NASA

"I think back in May we realized we had a huge challenge on our hands," said Michael Haddock, a mechanical engineer designing the procedures and other aspects of preparing R2 for launch, including careful crane operations inside the Space Station Processing Facility's high bay.

Though it was fast-paced, intense work, the payoff of getting to help R2 into space added extra motivation for the engineers involved.

By spaceflight standards, planning for the packing effort moved quite quickly, particularly considering R2 is perhaps the heaviest payload to be taken into space inside a cargo module.

"The mass is what's driving the crane operations, otherwise we'd be handling the robot by hand," Haddock said. "But the robot itself weighs on the order of 333 pounds and when it is installed in the structural launch enclosure, it will weigh over 500 pounds."

As they must when loading anything for spaceflight, the engineers designed the packaging so astronauts could easily remove R2 from its launch box, known by its acronym SLEEPR or Structural Launch Enclosure to Effectively Protect Robonaut.

"We were trying to do something very unique and very fast," said Scott Higginbotham, payload manager for the STS-133 mission. "And we've got the best team in the world for dealing with things like that."

There was talk of simply strapping the robot into the empty seat on the shuttle's middeck, Higginbotham said, but R2 was too heavy for that. So the teams came up with a plan to fasten R2 to a base plate and use struts to support the back and shoulders. Then dense foam will provide more support, followed by an aluminum frame. A clamshell of foam tops off the package.

Assembling the packing precisely is important for R2 because a space shuttle accelerates to more than three times the force of gravity during its eight-minute climb into orbit.

"The team had to educate ourselves, learn the uniqueness of it as well as learn how to install it into the vehicle," said Ken Koby, lead systems engineer for Boeing. "That's what the team has basically been doing every day for the last three months, educating ourselves about Robonaut."

Coincidentally, detailed analysis showed that R2's best position to withstand the launch forces will be the same as the astronauts -- facing toward the nose of the shuttle with the back taking all the weight.

"The orientation is just like the crew flies," Koby said. "The crew will be facing straight up on their backs and Robonaut will be the same direction, obviously 30 feet behind them in the module here."

The astronauts of STS-133 met Robonaut at NASA's Johnson Space Center before the launch of Discovery. Photo credit: NASA

Although the robot is fundamentally a very complex machine full of state-of-the-art sensors and operated by phenomenally sophisticated software, it is its shape that stirs fascination. Designed by NASA and General Motors as a robotic assistant for astronauts working in space, R2 looks like the upper torso of a sculpted bodybuilder and is topped with a helmeted head that includes two cameras to give it three-dimensional vision plus other sensors.

Its look has been compared to Star Wars bounty hunter Boba Fett, the endoskeleton from the Terminator films and the animated robot that plays football on Fox Sports.

"It's rather intimidating at first sight because of its size, its physique and you can't see its eyes," Haddock said.

"From the moment you walk into the room and see R2, it's everything you'd expect from a robot, from the gold-shield face to the thickness, the broadness of his shoulders," Koby said. "It's truly very science fiction-like, but it's all fact in this case."

It also has a pair of beefy arms and two hands, complete with four fingers and one thumb each, that can shake hands. Its programming is sensitive enough to respond to a handshake with the same amount of force as the person squeezing R2's hands. In other words, it can hold a piece of equipment in space without crushing it.

"It really grabs people's attention," said Higginbotham. "It's so incredibly cool. It can use the same tools and procedures as an astronaut."

This Robonaut was not meant to fly at first. Instead, it was strictly a developmental model to be tested and perfected on the ground. However, it was adapted for flight and has tested well for launch. That is a bit of a theme for the STS-133 mission because the Permanent Multipurpose Module that Discovery is taking to the station also was retrofitted to add more capabilities. The PMM was formerly a Multipurpose Logistics Module known as Leonardo and was built to stay in space for only short periods at a time. But its mission has changed and engineers built up its armor and added some interior features so it can be permanently attached to the station and used as more of a storage closet than the moving van first envisioned.

"Someone said this mission is anything but ordinary," said Higginbotham, "and that is a fact."

For more information visit http://www.nasa.gov/mission_pages/shuttle/behindscenes/robonautpacking.html

This Month in Exploration - August

From the early days of experimental airplanes to NASA’s soaring space shuttles, the evolution of flight has mirrored the evolution of society. The ongoing scientific discoveries that are part of aeronautics and space flight have improved life on Earth and allowed humans to begin investigating the secrets of the universe. “This Month in Exploration” presents the rich history of human flight, contextualizing where we’ve been and examining the exploration history NASA is making today.

100 Years Ago

August 31, 1910: Glenn Curtiss established a record for longest flight over water when he completed a course from Euclid beach in Cleveland, Ohio to Cedar Point in Sandusky, Ohio. Flying his biplane over Lake Erie parallel to the shore, Curtiss completed the trip in about an hour and fifteen minutes.

A Loening Amphibian aircraft similar to the three used on the MacMillan Arctic Expedition. Credit: NASA

85 Years Ago

August 1, 1925: Under the command of Lt. Cmdr. Richard E. Byrd, a U.S. Naval Air detail began aerial exploration of a 30,000-square-mile area near Etah, North Greenland using three Loening amphibian seaplanes introduced the previous year. The excursion was part of the MacMillan Arctic Expedition, the United States’ contribution to the global race to Earth’s last unexplored frontiers, the North and South Poles.

75 Years Ago

August 28, 1935: The Equipment Laboratory at Wright Field tested automatic radio-navigation equipment, called the Sperry automatic pilot, by mechanically linking it to a standard radio compass.

50 Years Ago

August 12, 1960: NASA launched its first communications satellite, the Echo 1, via a Thor- Delta rocket from Vandenberg Air Force Base. The satellite transmitted a radio message from President Dwight D. Eisenhower across the nation, demonstrating the feasibility of global radio communications via satellites. Echo 1 was the most visible and largest satellite launched at that time. Although the mission was successful, it was quickly superseded by active-repeater communications satellites such as Telstar.

A static inflation test of the 135 foot satellite Echo 1. Credit: NASA

45 Years Ago

August 21-29, 1965: NASA launched the Gemini-V via Titan-II rocket. Several records were set during this eight-day orbital flight, including the single longest manned spaceflight, total U.S. manned hours in space and a new altitude record for an American spacecraft. American astronaut Gordon Cooper was also the first man to make a second orbital flight and achieved the record for the most spaceflight time.

35 Years Ago

August 20, 1975: NASA launched Viking 1 from NASA’s Kennedy Space Center, Fla. It was the first of two spacecraft on the historic mission to the planet Mars. The primary objectives of the Viking mission were to return high-resolution images of the Martian surface, analyze the structure and composition of the atmosphere and surface and search for evidence of life on Mars.

25 Years Ago

August 27, 1985: NASA launched space shuttle Discovery (STS-51I) from NASA’s Kennedy Space Center, Fla. The shuttle deployed three communications satellites and retrieved, repaired and re-launched the TELSAT-1 Communications Satellite, Syncom IV-3.

10 Years Ago

August 9, 2000: The European Space Agency launched the second pair of Cluster II mission satellites, named Rumba and Tango, aboard a Soyuz-Fregat rocket from Russia’s Baikonur Cosmodrome. The Cluster mission used simultaneous measurements from four satellites to provide detailed analysis of the effects of solar wind on Earth’s magnetic field. The mission is still in effect today and has resulted in around 1000 scientific publications in peer-reviewed journals.

Astronaut Neil A. Armstrong in the Lunar Module during the Apollo 11 lunar landing mission. Credit: NASA

5 Years Ago

August 12, 2005: NASA launched the Mars Reconnaissance Orbiter (MRO) from NASA’s Kennedy Space Center, Fla. aboard the first Atlas V rocket used for an interplanetary mission. The ongoing mission was to map the physical features of Mars, including its atmosphere and its subterranean layering.

Present Day

August 5, 2010: Neil A. Armstrong turns 80 this year. Born in Wapakoneta, Ohio in 1930, Armstrong was the first person to walk on the moon. He is credited with the famous quote: "That's one small step for a man, one giant leap for mankind."

August 22, 2010: Science fiction writer Ray Bradbury was born 100 years ago on this day in Waukegan, Ill. He wrote “The Martian Chronicles” published in 1949. Among his poems is one inspired by a trip to NASA’s Kennedy Space Center, Fla. where he compared his tour of the Saturn hanger to “walking around inside Shakespeare’s head.”

For more information visit http://www.nasa.gov/exploration/thismonth/this_month_aug10.html

NASA Lightning Research Happens in a Flash

Lightning's connection to hurricane intensification has eluded researchers for decades, and for a riveting 40 days this summer, NASA lightning researchers will peer inside storms in a way they never have before.

Earth scientists and engineers at NASA's Marshall Space Flight Center in Huntsville, Ala., will soon fly the Lightning Instrument Package, or LIP, a flight instrument designed to track and document lightning as hurricanes develop and intensify. In August and September, LIP will fly on a remotely piloted Global Hawk airplane over the Gulf of Mexico and Atlantic Ocean at an altitude of 60,000 feet. LIP will be part of a NASA hurricane study called Genesis and Rapid Intensification Processes, or GRIP for short. The study involves three storm chaser planes mounted with 15 instruments. LIP and the other instruments will work together to create the most complete view of hurricanes to date.

Dr. Richard Blakeslee (right) and Tony Kim (left) of the Marshall Center test the electric field mills used to measure lightning produced by thunderstorms. (NASA/MSFC/D. Stoffer)

"We're now putting LIP on an aircraft that can stay in the air for 30 hours," said Richard Blakeslee LIP principal investigator and Earth scientist at the the Marshall Center. "That’s unprecedented. We typically fly on airplanes that fly over a storm for a period of 10-15 minutes. But this plane can stay with a storm for hours."

"We'll be able to see a storm in a way we’ve never seen it before," he added. "We'll see how the storm develops over the long term, and how lightning varies with all the other things going on inside a hurricane. It's the difference between a single photograph and a full-length movie. That’s quite a paradigm shift."

While scientists know an increase in lightning means the storm is changing, it remains a mystery as to whether that increase signifies strengthening or weakening. Though scientists have quite a few ideas, they lack the data to firmly establish a concrete relationship. Researchers hope LIP's upcoming flights will change that. If scientists can figure out the ties between lightning and hurricane severity, meteorologists may be able to greatly improve their short-term forecasts. Researchers have connected lightning to everything from strong winds to flooding to tornadoes, and a few extra minutes of warning time can save lives each year.

The Lightning Instrument Package will fly aboard the Global Hawk, a remotely piloted airplane that reaches altitudes of 60,000 feet, about twice the height of a commercial airliner. LIP has flown numerous times before, but will now be on an aircraft that can stay in the air for 30 hours, an unprecedented improvement. (NASA)

"We can use lightning as a natural sensing tool to see into the heart of a storm," said Blakeslee. "Lightning allows us to get at rain and other processes going on within a storm."

For Blakeslee and the rest of the LIP team, the hurricane study this fall presents a tremendous opportunity. In its nearly 15-year lifespan, LIP has flown nearly 100 missions in 10 major field campaigns, soaring over more than 800 storms. That's unparalleled for a lightning instrument, according to Blakeslee, and LIP researchers hope it will continue its long tradition of successful research.

The Guts of the Lightning Instrument Package

LIP's instruments may look simple, but they're surprisingly complex. To measure the electric field in a storm, the instrument relies on electric field mills, devices that allow scientists to measure the amount of lightning a storm produces. Originally developed at NASA, the mills look like big cans -- each about a foot long and approximately 8 inches across. As the instrument flies through the air, a plate covering each can rotates, covering and uncovering four metal disks housed inside. Uncover a disk and electricity from the storm rushes in. Cover the disk and it rushes back out. The whole process converts the electrical current from DC to AC and back to DC, allowing scientists to measure how strong a storm's electric field is, and how prone to lightning it might be. A sudden shift in the strength of the electrical field allows scientists to determine that a lightning strike has occurred.

In addition, a conductivity probe reveals how easily electrical current can flow through the storm to the upper part of the atmosphere. The probe is a small nose-cone shaped device with two sensor tubes attached to each side. As the plane flies near a hurricane, small electrical particles called ions rush through the tube, allowing the team to count them.

The instrument will measure the amount of lightning produced by hurricanes and tropical storms. Lightning’s connection to hurricane intensification has eluded researchers for decades, and NASA scientists hope the upcoming hurricane experiment will help answer some puzzling questions. (NASA)

The LIP team uses all that data to determine how much lightning a hurricane produces and where it originates within the storm. By combining that data with wind speed, rainfall rate and other information, researchers can connect how lightning relates to hurricane intensification. And because Blakeslee and his team get their data real time, they can redirect the plane as needed to improve the likelihood of quality results.

After the summer hurricane study ends in September, the team will analyze, evaluate, and eventually release the data, a process which should take several months. Following that, the Lightning Instrument Package will continue to fly in hurricane and storm studies in hopes of collecting more data. The more data, the better the forecasts, Blakeslee said -- and the nearer scientists move to understanding these powerful storms.
The Long Journey of LIP

Of course, Blakeslee and the rest of the LIP team have had to overcome their fair share of challenges.

"When we first started out, we didn’t even know if what we do now was possible," Blakeslee said. "One of my colleagues told me, 'You won’t be able to make current measurements over storms.' But I said, 'Yes we can.' And now we do."

Lightning can serve as a natural sensing tool that allows scientists to understand what else could be happening in a storm. (National Weather Service/F. Smith)

"It's a pretty rewarding feeling," he said. "The biggest challenge now is that there’s always more to study than we possibly can. We've got to pick and choose, and sometimes that can be frustrating."

But for Blakeslee, there's nothing else he'd rather do.

"Lightning is just cool," he laughed. "I've always enjoyed hands-on science, and everything about lightning measurements is hands-on science. You build the instruments. You put them on airplanes. You go out and fly them. You get back the data. And then there's the satisfaction that it’s not all abstract -- we can actually apply what we're learning to real people, real situations and real problem-solving."

For now, the LIP team looks forward with anticipation to sending their instrument out on an unprecedented journey -- hopefully one that will bring scientists one step closer to solving one of science’s biggest mysteries.

For more information about NASA storm research and upcoming study, visit:

http://www.nasa.gov/grip

For more information visit http://www.nasa.gov/mission_pages/hurricanes/missions/grip/news/lightning.html

NASA Spacecraft Camera Yields Most Accurate Mars Map Ever

PASADENA, Calif. -- A camera aboard NASA's Mars Odyssey spacecraft has helped develop the most accurate global Martian map ever. Researchers and the public can access the map via several websites and explore and survey the entire surface of the Red Planet.

The map was constructed using nearly 21,000 images from the Thermal Emission Imaging System, or THEMIS, a multi-band infrared camera on Odyssey. Researchers at Arizona State University's Mars Space Flight Facility in Tempe, in collaboration with NASA's Jet Propulsion Laboratory in Pasadena, Calif., have been compiling the map since THEMIS observations began eight years ago.

The pictures have been smoothed, matched, blended and cartographically controlled to make a giant mosaic. Users can pan around images and zoom into them. At full zoom, the smallest surface details are 100 meters (330 feet) wide. While portions of Mars have been mapped at higher resolution, this map provides the most accurate view so far of the entire planet.

The new map is available at: http://www.mars.asu.edu/maps/?layer=thm_dayir_100m_v11 .

Advanced users with large bandwidth, powerful computers and software capable of handling images in the gigabyte range can download the full-resolution map in sections at: http://www.mars.asu.edu/data/thm_dir_100m .

Valles Marineris, the "Grand Canyon of Mars," sprawls wide enough to reach from Los Angeles to nearly New York City, if it were located on Earth. The red outline box shows the location of a second, full-resolution image. Credit: NASA/JPL/Arizona State University

"We've tied the images to the cartographic control grid provided by the U.S. Geological Survey, which also modeled the THEMIS camera's optics," said Philip Christensen, principal investigator for THEMIS and director of the Mars Space Flight Facility. "This approach lets us remove all instrument distortion, so features on the ground are correctly located to within a few pixels and provide the best global map of Mars to date."

Working with THEMIS images from the new map, the public can contribute to Mars exploration by aligning the images to within a pixel's accuracy at NASA's "Be a Martian" website, which was developed in cooperation with Microsoft Corp. Users can visit the site at: http://beamartian.jpl.nasa.gov/maproom#/MapMars .

"The Mars Odyssey THEMIS team has assembled a spectacular product that will be the base map for Mars researchers for many years to come," said Jeffrey Plaut, Odyssey project scientist at JPL. "The map lays the framework for global studies of properties such as the mineral composition and physical nature of the surface materials."

Other sites build upon the base map. At Mars Image Explorer, which includes images from every Mars orbital mission since the mid-1970s, users can search for images using a map of Mars at: http://themis.asu.edu/maps .

"The broad purpose underlying all these sites is to make Mars exploration easy and engaging for everyone," Christensen said. "We are trying to create a user-friendly interface between the public and NASA's Planetary Data System, which does a terrific job of collecting, validating and archiving data."

This image shows a 90-mile-wide portion of the giant Valles Marineris canyon system. Landslide debris and gullies in the canyon walls on Mars can be seen at 100 meters (330 feet) per pixel. Credit: NASA/JPL/Arizona State University

Mars Odyssey was launched in April 2001 and reached the Red Planet in October 2001. Science operations began in February 2002. The mission is managed by JPL for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver is the prime contractor for the project and built the spacecraft. NASA's Planetary Data System, sponsored by the Science Mission Directorate, archives and distributes scientific data from the agency's planetary missions, astronomical observations, and laboratory measurements.

For more information about NASA's Odyssey spacecraft, visit: http://mars.jpl.nasa.gov/odyssey .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

For more information visit http://www.nasa.gov/mission_pages/odyssey/odyssey20100723.html

Saturn System Moves Oxygen From Enceladus to Titan

Complex interactions between Saturn and its satellites have led scientists using NASA's Cassini spacecraft to a comprehensive model that could explain how oxygen may end up on the surface of Saturn's icy moon Titan. The presence of these oxygen atoms could potentially provide the basis for pre-biological chemistry.

The interactions are captured in two papers, one led by John Cooper and another led by Edward Sittler, published in the journal Planetary and Space Science in late 2009. Cooper and Sittler are Cassini plasma spectrometer team scientists at NASA's Goddard Space Flight Center in Greenbelt, Md.

"Titan and Enceladus, another icy moon of Saturn, are chemically connected by the flow of material through the Saturn system," Cooper said.

In one paper, Cooper and colleagues provide an explanation for forces that could generate the Enceladus geysers that spew water vapor into space. In the other, published in the same issue, Sittler and colleagues describe a unique new process in which oxygen that circulates in the upper atmosphere of Titan can be carried all the way to the surface without further chemical contamination by being encased in carbon cages called fullerenes.

The work draws upon previous work by Sittler and others that model the dynamics of how particles, including water molecules, travel from Enceladus to Titan. At Enceladus the flow process begins with what they call the "Old Faithful" model, after the Old Faithful geyser in Yellowstone National Park. In this model, gas pressure slowly builds up inside Enceladus, then gets released occasionally in geyser-like eruptions.

Unlike terrestrial geysers, or even geyser-like forces on Jupiter's moon Io, the model proposed by Cooper shows that charged particle radiation raining down from Saturn’s magnetosphere can create the forces from below the surface that are required to eject gaseous jets.

Energetic particles raining down from Saturn's magnetosphere – at Enceladus, mostly electrons from Saturn's radiation belts -- can break up molecules within the surface. This process is called radiolysis. Like a process called photolysis, in which sunlight can break apart molecules in the atmosphere, energetic radiation from charged particles that hit an icy surface, like that of Enceladus, can cause damage to molecules within the ice. These damaged molecules can get buried deeper and deeper under the surface by the perpetual churning forces that can repave the icy surface. Meteorites constantly crashing into the surface and splashing out material might also be burying the molecules.

This annotated image collage features Saturn and the moons Titan, Enceladus, Dione, Rhea and Helene, which are being studied by the Cassini mission. Image credit: NASA/JPL/Space Science Institute

When chemically altered icy grains come into contact beneath the surface with icy contaminants such as ammonia, methane and other hydrocarbons, they can produce volatile gases that can explode outward. Such gases can create plumes of the size seen by Cassini. Cooper and colleagues call such icy volatile mechanics "cryovolcanism."

What's unique about the "Old Faithful" model is that it "is a model for cryovolcanism that is based on not only liquid water, but also requires the production of gases by the radiolytic chemistry observed at Enceladus," said Sittler.

The plumes that emanate from Enceladus' south polar region consist of water, ammonia and other compounds. Scientists have known since the 1980s that Saturn's magnetosphere is inexplicably filled with neutral particles. In the intervening decades, particularly since the discovery of plumes jetting out from the south pole of Enceladus, work has shown how some of the water molecules that escape from Enceladus get split up into neutral and charged particles and are transported throughout Saturn's magnetosphere.

Sittler's new model indicates that as these broken water molecules enter Titan's atmosphere, they may be captured by fullerenes—hollow, soccer-ball shaped shells made of carbon atoms. Although the heavy molecules Cassini has detected in the upper atmosphere of Titan may be other molecules, Sittler suggests they are likely fullerenes.

In Sittler's model, the fullerenes then condense into larger clusters that can attach to polycyclic aromatic hydrocarbons—chemical compounds also found on Earth in oil, coal and tar deposits, and as the byproducts of burning fossil fuels. The fullerene clusters form even larger aerosols that travel down to Titan's surface.

This process protects the trapped oxygen from Titan's atmosphere, which is saturated with hydrogen atoms and compounds that are capable of breaking down other molecules. Otherwise, the oxygen would combine with methane in Titan's atmosphere and form carbon monoxide or carbon dioxide. Until now, scientists have not been able to explain how oxygen fits into the picture of the dynamics and chemistry of Saturn and its moons.

As the oxygen-rich aerosols fall to Titan's surface, they are further bombarded by products of galactic cosmic ray interactions with Titan's atmosphere. Cosmic rays bombarding the oxygen-stuffed fullerenes could produce more complex organic materials, such as amino acids, in the carbon-rich and oxygen-loaded fullerenes. Amino acids are considered important for pre-biological chemistry.

Scientists have been able to couple the new models that describe the generation of plumes at Enceladus and oxygen ion capture in fullerenes near the top of Titan's atmosphere to existing theories of the transport of oxygen across the magnetosphere. Taken together, Sittler and Cooper suggest a chemical pathway that allows the oxygen to be introduced to Titan's surface chemistry.

"Cooper and Sittler's work helps us understand more about the potential for chemical interactions among Saturn's moons," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"The Saturn system is indeed a dynamic place, with the Enceladus plumes creating the E ring and loading the magnetosphere with water which interacts with Titan and the other moons," Spilker said.

The Cassini mission is a joint effort of NASA, the European Space Agency, and the Italian space agency Agenzia Spaziale Italiana. The mission is managed for NASA by the Jet Propulsion Laboratory, a division of the California Institute of Technology. Partners include the U.S. Air Force, Department of Energy, and academic and industrial participants from 19 countries.

For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/saturn20100701.html

NASA Retires TRACE Spacecraft After Highly Successful Mission

NASA's Transition Region And Coronal Explorer, known as TRACE, conducted its final observations of the sun on June 21.

Although launched on April Fools' Day, 1998, TRACE quickly proved its worth, observing – for the first time - an entire cycle of solar activity and imaging dynamic coronal phenomena.

TRACE provided images at five times the magnification of those taken by the Extreme Ultraviolet Imaging Telescope Instrument aboard the Solar and Heliospheric Observatory (SOHO).

TRACE spacecraft from video

Many details of the fine structure of the corona were observed for the first time. Early in its mission, it discovered the fine-scale magnetic features where enhanced heating occurs at the footpoints of coronal loop systems in solar active regions, which later became known as "coronal moss."

In 2001, TRACE observations of astonishing coronal activity were highlighted in the IMAX movie SolarMax.

High spatial resolution observations of the solar corona are now being carried out by NASA''s newest eye on the sun, the Solar Dynamics Observatory, a Goddard-built spacecraft managed by the Science Mission Directorate's Heliophysics Division. SDO's field of view is much larger than TRACE, so that the entire disk of the sun, not a small area, is imaged in every observation.

The TRACE spacecraft observes an X-ray flare over solar active region AR9906, April 21, 2002.

Lockheed-Martin Solar and Astrophysics Laboratory in Palo Alto, Calif., developed the TRACE instrument and NASA Goddard Space Flight Center's Flight Projects Directorate designed and built this Small Explorer class spacecraft. The entire mission was accomplished for $10M under budget.

During its 12 year mission, TRACE produced millions of stunning images and contributed to more than 1,000 scientific publications.

Congratulations to TRACE mission team and numerous other scientists and engineers who contributed the mission’s outstanding success.

For more information visit http://www.nasa.gov/topics/solarsystem/sunearthsystem/main/trace-retires.html