New technology - Versatile Small-Scale Rocket Motor Test Evaluates New Materials

Fire and sparks flew as a 24-inch-diameter solid rocket motor was successfully tested May 27 at NASA's Marshall Space Flight Center in Huntsville, Ala. The 21-second firing tested a NASA sub-scale motor designed as a versatile, quick-turnaround and low-cost way to determine the performance of new materials and designs.

This 24-inch-diameter, 109-inch-long motor utilized propellant and a case reconfigured from space shuttle test equipment. The test motor’s nozzle was replaced with a new design scaled from the Ares I first-stage development motor, but could also be modified to accommodate different mission profiles or different sized vehicles, including heavy-lift vehicles.

The test data will be evaluated to better understand the performance of the new nozzle configuration, processes and materials.

"A rocket's nozzle needs to be protected from the incredibly harsh environment to which it is exposed during launch. A full-scale solid rocket motor's nozzle must survive a two minute launch at over 5000-degrees Fahrenheit," said Scott Ringel, an engineer at the Marshall Center and the design lead for this test. "We need to ensure our materials and designs can hold up, and small-scale tests like this one give us added confidence."

NASA is a unique customer for many materials and requires highly reliable systems, thoroughly tested and evaluated for human spaceflight programs. One change in the availability of a part, supplier or material can potentially impact vehicle design, flight operations and mission assurance. Finding adequate replacements involves extensive testing and qualification efforts. Testing a sub-scale version of a rocket motor is a cost-effective way to assess new materials, technologies or processes, and rapidly evaluate performance.

"We have extensive experience with thousands of materials used in the shuttle program, but many have become obsolete because of environmental concerns or industrial trends," added Ringel. "As new technologies drive the development of new materials, sub-scale testing ensures we can effectively replace obsolete materials with new and improved options."

The test also includes two secondary objectives.

The engineering team introduced an intentional defect into the propellant. A small cut was placed in the propellant inner diameter to verify the analytic methodology used to determine critical flaw sizes. The team hopes to gain a better understanding for the margin for error.

In addition, NASA's Engineering and Safety Center will use data gleaned from this test to better understand the acoustics and vibration environment resulting from the rocket motor’s plume.

Engineers from the Marshall Center's Engineering Directorate designed the test article with support from ATK Aerospace Systems of Huntsville, Ala.

Future aircraft Supersonic Green Machine

This future aircraft design concept for supersonic flight over land comes from the team led by the Lockheed Martin Corporation.

The team's simulation shows possibility for achieving overland flight by dramatically lowering the level of sonic booms through the use of an "inverted-V" engine-under wing configuration. Other revolutionary technologies help achieve range, payload and environmental goals.

This supersonic cruise concept is among the designs presented in April 2010 to the NASA Aeronautics Research Mission Directorate for its NASA Research Announcement-funded studies into advanced aircraft that could enter service in the 2030-2035 timeframe.

Mysterious River Channels on the Moon

Rilles are long, narrow depressions on the lunar surface that look like river channels. Some are straight, some curve, and others, like the ones highlighted here, are called "sinuous" rilles and have strong meanders that twist and turn across the moon. Rilles are especially visible in radar imagery, like that gathered by LRO's Mini-RF instrument. The formation of lunar rilles is not well understood. It is believed there may be many different formation mechanisms including ancient magma flows and the collapse of subterranean lava tubes. Imagery from LRO will help researchers to better understand these mysterious "river-like" lunar features.

Spacecraft’s re-entry

The Japan Aerospace Exploration Agency’s Hayabusa spacecraft streaked across the sky like a saber of light through the clouds as it re-entered Earth’s atmosphere over the Woomera Test Range in Australia. In Kingoonya, the spacecraft’s re-entry was visible to the human eye for only 15 seconds.

NASA’s first oceanographic research Voyage Begins

NASA’s first oceanographic research expedition got underway this morning as the U.S. Coast Guard icebreaker Healy steamed out of this island fishing port in the North Pacific. The five-week ICESCAPE mission, which stands for "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," is now heading for the Bering Strait on its way north into the Chukchi and Beaufort seas.

The science teams on the mission spent a full day on Monday loading scientific gear and supplies onto the Healy, unpacking equipment, and setting up laboratory space. "It's been kind of a crazy day," said ICESCAPE chief scientist Kevin Arrigo of Stanford University. "There are a lot of people – nearly 50 scientists -- and a lot to set up. Doing all that in one day is not a lot of time. But the Healy crew has been great in helping us get everything set up."

NASA is sponsoring the research expedition to explore how changes in the Arctic sea ice cover are altering the ocean ecology in the region. The scientists onboard will take a detailed look at how changing conditions in the Arctic are affecting the ocean’s chemistry and biology that play a critical role in global climate change.

"This is a really exciting cruise for me," said ICESCAPE co-chief scientist Don Perovich of the U.S. Army's Cold Regions Research and Engineering Laboratory, Hanover, N.H. "I've been on a lot of cruises to polar regions. I've probably spent a year and a half of my life on icebreaker cruises. But this is the first time I've been out with a large group of biologists and biogeochemists, and that's really exciting."

What’s in every breath you take?

Traveling to Los Angeles can be a hazardous undertaking. The buzzing coastal city at the very edge of the American frontier has long been a symbol of exploration and progress. As planes land in L.A., they must first penetrate the dark, ominous cloud that hangs constantly above the skyscrapers. Smog lies over L.A. like a thick blanket, dimming the sunshine of the Golden State.

To some degree, scientists have been aware of air pollution for centuries, but it wasn't until the late 1940s that some of the causes were recognized. Since then, most atmospheric chemistry has focused on gas-phase interactions, as the majority of the atmosphere is a continuous gas phase, or reactions in the liquid phase, taking place within droplets of condensed matter. But these chemical models do not account for a significant portion of what is happening in the air above us.

A large number of atmospheric reactions occur under conditions we know very little about, and the Holy Grail of atmospheric chemistry has become developing a basic, molecular-level understanding of the reactions that occur in this mystery world--at the air-water interface, where the gas phase meets the liquid phase, and the reactions bear no resemblance to either phase alone.

In order to study these processes, Barbara Finlayson-Pitts and her team, first funded by the National Science Foundation's (NSF)Chemistry Division in 2002, have developed the Atmospheric Integrated Research for Understanding Chemistry at Interfaces (AirUCI) collaboration. The goal of AirUCI is to find that Holy Grail and develop the necessary understanding of the air-water interface and its effect on air quality. AirUCI uses an integrated approach, including experiments, theory and computer modeling to expand the very small amount of existing knowledge about reactions at interfaces.

The urgency of AirUCI's research comes from an understanding of how fragile the air we breathe truly is.

"Ninety-nine percent of the atmosphere is in the lowest 30 kilometers, concentrated in this tenuous layer we live in," says Mike Ezell, a senior researcher in Finlayson-Pitts's lab.

Ezell's work, like much of the work at AirUCI, focuses on aerosol particles, miniscule suspensions of matter in the air. The properties of aerosol particles have enormous implications for global climate change. Aerosol particles act as condensation nuclei for clouds, which need particles to form. Smaller particles result in smaller cloud droplets and longer-lived clouds, resulting in more reflected radiation and a greater cooling effect. Some larger particles, like soot, absorb light, causing a warming effect. In addition, the particles themselves scatter light, affecting the amount of radiation that reaches the Earth's surface.

"Climate change and air pollution are very closely linked," says Finlayson-Pitts. "One of the points people tend to miss in the debate on climate change is how much air pollution is really a factor. It isn't all about carbon dioxide."

Finlayson-Pitts' team is also concerned with the health effects of emissions, particularly in the production of ozone. Ozone, while a significant gas high in the stratosphere, is a health risk when produced in our tropospheric home. Researchers in the Nizkorodov lab at AirUCI are focused on the production of ozone from the commercial air purifiers that provide clean, safe air in our homes. Commercial air purifiers break up oxygen gas (O2) into single oxygen atoms, which can recombine into ozone (O3). Especially when placed in small rooms, these machines can rapidly increase the amount of the hazardous gas to a dangerous level, which has known severe effects on the lungs, causing cough, pain and shortness of breath.

The other source of ozone the team is studying, highlighted in 2000 and 2005 articles in Science, is the oxidation of chloride ions (Cl-) by hydroxide (OH) on the surface of particles, and producing chloride gas (Cl2). The gas photolyzes easily, splitting into chlorine atoms (Cl), which react very quickly with almost all organic particles, like those that we emit, producing a large amount of ozone as well as other pollutants. The AirUCI labs showed for the first time that this reaction occurs very quickly at the air-water interface, as chloride ions are readily available, demonstrated by theoretical models, and the surface reaction does not require the same conditions that the same reaction would require in the bulk of a liquid droplet.

The Hemminger lab works with AirUCI to develop a fundamental understanding of reactions at solution interfaces. At the same time, other researchers in the lab are a part of an effort, funded by the Department of Energy and the California Community Foundation, to solve some energy issues. As demand for energy continues to outstrip the available supply, new technology to make clean, efficient energy possible becomes a more urgent need.

The vast majority of these technologies are simply not ready for the market; according to John Hemminger, widespread use of solar panels may be economically feasible in several decades, but even then, it may not be able to compete with oil in a free market. "Between us and feasible solar energy is either $200 per barrel oil, or fundamental science," says Hemminger.

In order to address this pressing need, the Hemminger lab is working on understanding radiation interactions on matter, focusing on radiation on surfaces, in the hopes of developing new, more efficient methods of harnessing the sun's energy.

Uncovering the secrets of air-water interfaces is not the only duty that AirUCI has taken on. "We are committed to conveying that to the public and K-12 educators," Finlayson-Pitts says. Each year, the AirUCI teacher workshop brings in middle and high school teachers, giving them lectures from leaders in the field of atmospheric chemistry as well as valuable experience using top-of-the-line lab equipment. Teachers then take the information they gain back to their classrooms.

"If we want to develop the next generation in science and technology, and if we want taxpayers to support us," says Finlayson-Pitts, "it is important that we interface with the public, invite them in, and show them what we are doing. It is an important responsibility."

AirUCI's research is illuminating a world of reactions that have powerful implications for each breath we take, as well as for projections of future conditions. Currently, the models used to predict future air and climate conditions do not account for air-water interface chemistry, because the fundamental understanding of these processes is not there.

"People know surface chemistry is happening, but it's not in the models. We need a molecular-level understanding of the processes occurring on surfaces in order to tell the modelers what to put in the models to accurately represent this chemistry and its potential effects," says Finlayson-Pitts.

And until we know what is truly happening in the air above us, there is no way to comprehend the full scope of effects and consequences our activities have on our world and on our future.

Aurora

An aurora is a natural display of light in the sky that can be seen with the unaided eye only at night. An auroral display in the Northern Hemisphere is called the aurora borealis, or the northern lights. A similar phenomenon in the Southern Hemisphere is called the aurora australis. Auroras are the most visible effect of the sun's activity on the earth's atmosphere.

Most auroras occur in far northern and southern regions. They appear chiefly as arcs, clouds, and streaks. Some move, brighten, or flicker suddenly. The most common color in an aurora is green. But displays that occur extremely high in the sky may be red or purple. Most auroras occur about 60 to 620 miles (97 to 1,000 kilometers) above the earth. Some extend lengthwise across the sky for thousands of miles or kilometers.

A bar magnet has a magnetic field like that of the sun. Field lines, which represent the field, exit the north pole and enter the south pole.

A bar magnet has a magnetic field like that of the sun. Field lines, which represent the field, exit the north pole and enter the south pole. Image credit: World Book diagram by Precision Graphics
Auroral displays are associated with the solar wind, a continuous flow of electrically charged particles from the sun. When these particles reach the earth's magnetic field, some get trapped. Many of these particles travel toward the earth's magnetic poles. When the charged particles strike atoms and molecules in the atmosphere, energy is released. Some of this energy appears in the form of auroras.

Auroras occur most frequently during the most intense phase of the 11-year sunspot cycle. During this phase, dark patches on the sun's surface, called sunspots, increase in number. Violent eruptions on the sun's surface, known as solar flares, are associated with sunspots. Electrons and protons released by solar flares add to the number of solar particles that interact with the earth's atmosphere. This increased interaction produces extremely bright auroras. It also results in sharp variations in the earth's magnetic field called magnetic storms. During these storms, auroras may shift from the polar regions toward the equator.

Hayabusa spacecraft Comes Home

The Hayabusa capsule and bus entered the Earth's atmosphere over Woomera, Australia, on June 13 at 11:21 p.m. local time. From the perspective of NASA's DC-8 airborne observation team, the capsule moved below and slightly ahead of the bus and stayed clear of the spectacular breakup of the bus. After the bus had disintegrated, the capsule continued to create a wake, before reaching peak heating and then fading gradually.

That's when the Japan Aerospace Exploration Agency (JAXA) expects the sample return capsule of the agency's technology demonstrator spacecraft, Hayabusa, to boomerang back to Earth. The capsule, along with its mother ship, visited a near-Earth asteroid, Itokawa, five years ago and has logged about 2 billion kilometers (1.25 billion miles) since its launch in May 2003.

With the return of the Hayabusa capsule, JAXA concluded a remarkable mission of exploration -- one in which NASA scientists and engineers played a contributing role.

"Hayabusa will be the first space mission to have made physical contact with an asteroid and returned to Earth," said Tommy Thompson, NASA's Hayabusa project manager from the Jet Propulsion Laboratory in Pasadena, Calif. "The mission and its team have faced and overcome several challenges over the past seven years. This round-trip journey is a significant space achievement and one which NASA is proud to be part of."

Launched May 9, 2003, from the Kagoshima Space Center, Uchinoura, Japan, Hayabusa was designed as a flying testbed. Its mission: to research several new engineering technologies necessary for returning planetary samples to Earth for further study. With Hayabusa, JAXA scientists and engineers hoped to obtain detailed information on electrical propulsion and autonomous navigation, as well as an asteroid sampler and sample reentry capsule.

The 510-kilogram (950-pound) Hayabusa spacecraft rendezvoused with asteroid Itokawa in September 2005. Over the next two-and-a-half months, the spacecraft made up-close and personal scientific observations of the asteroid's shape, terrain, surface altitude distribution, mineral composition, gravity, and the way it reflected the sun's rays. On Nov. 25 of that year, Hayabusa briefly touched down on the surface of Itokawa. That was only the second time in history a spacecraft descended to the surface of an asteroid (NASA's Near Earth Asteroid Rendezvous-Shoemaker spacecraft landed on asteroid Eros on Feb. 12, 2001). Hayabusa marked the first attempt to sample asteroid surface material.

The spacecraft departed Itokawa in January 2007. The road home for the technology demonstrator has been a long one, with several anomalies encountered along the way. But now the spacecraft is three days away from its home planet, and the Australian government, working closely with JAXA, has cleared the mission for landing. A team of Japanese and American navigators is guiding Hayabusa on the final leg of its journey. Together, they calculate the final trajectory correction maneuvers Hayabusa's ion propulsion system must perform for a successful homecoming.

"We have been collaborating with the JAXA navigators since the launch of the mission," said Shyam Bhaskaran, a member of JPL's Hayabusa navigation team. "We worked closely with them during the descents to the asteroid, and now are working together to guide the spacecraft back home."

To obtain the data they need, the navigation team frequently calls upon JAXA's tracking stations in Japan, as well as those of NASA's Deep Space Network, which has antennas at Goldstone, in California's Mojave Desert; near Madrid, Spain; and near Canberra, Australia. In addition, the stations provide mission planners with near-continuous communications with the spacecraft to keep them informed on spacecraft health.

"Our task is to help advise JAXA on how to best get a spacecraft traveling at 12.2 kilometers per second (27,290 miles per hour) to intersect a very specific target point 200 kilometers (120 miles) above the Earth," said Bhaskaran. "Once that is done, and the heat shield of the sample return capsule starts glowing from atmospheric friction, our job is done."

While atmospheric entry may be the end of the line for the team that has plotted the spacecraft's every move for the past 2 billion kilometers, NASA's involvement continues for the craft's final 200 kilometers (120 miles), to the surface of the Australian Outback. A joint Japanese-U.S. team operating on the ground and in the air will monitor this most critical event to help retrieve the capsule and heat shield.

"This is the second highest velocity re-entry of a capsule in history," said Peter Jenniskens, a SETI Institute scientist at NASA's Ames Research Center in Moffett Field, Calif. "This extreme entry speed will result in high heating rates and thermal loads to the capsule's heat shield. Such manmade objects entering with interplanetary speed do not happen every day, and we hope to get a ringside seat to this one."

Jenniskens is leading an international team as it monitor the final plunge of Hayabusa to Earth using NASA's DC-8 airborne laboratory, which is managed and piloted by a crew from NASA's Dryden Flight Research Center, Edwards, Calif. The DC-8 flies above most clouds, allowing an unfettered line of sight for its instrument suite measuring the shock-heated gas and capsule surface radiation emitted by the re-entry fireball.

The data acquired by the high-flying team will help evaluate how thermal protection systems behave during these super-speedy spacecraft re-entries. This, in turn, will help engineers understand what a sample return capsule returning from Mars would undergo. The Hayabusa sample return capsule re-entry observation will be similar to earlier observations by the DC-8 team of NASA's Stardust capsule return, and the re-entry of the European Space Agency's ATV-1 ("Jules Verne") automated transfer vehicle.

Soon after the sample return capsule touches down on the ground, Hayabusa team members will retrieve it and transport it to JAXA's sample curatorial facility in Sagamihara, Japan. There, Japanese astromaterials scientists, assisted by two scientists from NASA and one from Australia, will perform a preliminary cataloging and analysis of the capsule's contents.

"This preliminary analysis follows the basic protocols used for Apollo moon rocks, Genesis and Stardust samples," said Mike Zolensky, a scientist at NASA's Astromaterials Research and Exploration Science Directorate at the Johnson Space Center, Houston. "If this capsule contains samples from the asteroid, we expect it will take a year to determine the primary characteristics of the samples, and learn how to best handle them. Then the samples will be distributed to scientists worldwide for more detailed analysis."

"The Japanese and NASA engineers and scientists involved in Hayabusa's return from asteroid Itokawa are proud of their collaboration and their joint accomplishments," said Thompson. "Certainly, any samples retrieved from Itokawa will provide exciting new insights to understanding the early history of the solar system. This will be the icing on the cake, as this mission has already taught us so much. "

Scientists Use New Technique Grow Cells in 3-D Using Magnetic Fields

Cells in the human body live in amazingly complex, three-dimensional environments that are crucial for the cells' proper function. The lung, for example, consists of layers of different kinds of cells that work together to exchange oxygen and carbon dioxide between the air and the blood.

The way these cells work together, and the chemicals that they express to communicate with one another, change when they live on a flat, two-dimensional surface.

Given these differences in cell behavior and expression, it's intriguing that the standard for testing new drugs and chemicals are tests that use cells grown in flat-bottomed Petri dishes.

In an effort to more accurately mimic the effect of drugs or toxic chemicals on real living tissue, scientists from Rice University and the University of Texas' M.D. Anderson Cancer Center in Houston have developed a new laboratory technique that uses magnetic levitation to grow cells in three-dimensional shapes. Compared with cell cultures grown on flat surfaces, these 3-D cell cultures form tissues that more closely resemble those inside the body. The technique has the potential to drastically reduce the cost of developing new drugs, as well as reduce the use of animals when testing the safety of manufactured chemicals. The team's results were published in March 2010 in Nature Nanotechnology.

"There's a big push right now to find ways to grow cells in 3-D because the body is 3-D, and cultures that more closely resemble native tissue are expected to provide better results for pre-clinical drug tests," said study co-author Tom Killian, associate professor of physics at Rice. "If you could improve the accuracy of early drug screenings by just 10 percent, it's estimated you could save as much as $100 million per drug."

The new technique is an example of the innovation that can result when experts come together from disparate fields. Killian uses magnetic fields to trap and manipulate atoms that have been cooled to near absolute zero. He had been working on a new project with Rice bioengineer Robert Raphael on methods to use magnetic fields to probe cellular membranes.

One day, Killian's friend, Glauco Souza, who was then studying with the center's professors, Wadih Arap and Renata Pasqualini, mentioned that he was developing a gel that could load cells with magnetic nanoparticles.

"We wondered if we might be able to use magnetic fields to levitate the treated cells off the bottom of the petri dish, allowing them to grow in 3-D," said Souza, who left M.D. Anderson in 2009 to co-found Nano3D Biosciences, a startup that subsequently licensed the technology from Rice and M.D. Anderson.

"When we tried it," Killian said, "we were shocked by how robustly the cells grew and how they displayed tissue shapes that resembled real tissue."

The 3-D technique is simple, fast, and requires no special equipment. These are big advantages compared to other technologies that have attempted to take cell culturing into the third dimension.

Souza said Nano3D Biosciences is conducting additional tests, and he is hopeful they will show magnetic levitation is as good, if not better, than longstanding techniques for growing 3-D cell cultures with scaffolds.

Nano3D Biosciences also has a grant from the National Science Foundation (NSF) to use the technique to grow a layered model of lung tissue that can be used to test the toxicity of airborne chemicals.

Co-authors on the Nature Nanotechnology paper include Robert Raphael, Daniel Stark, Jeyarama Ananta and Thomas Killian of Rice; Glauco Souza and Carly Levin of Nano3D Biosciences; and Jennifer Molina, Michael Ozawa, Lawrence Bronk, Jami Mandelin, Maria-Magdalena Georgescu, James Bankson, Juri Gelovani, Wadih Arap and Renata Pasqualini, all of M.D. Anderson.

The research was funded by NSF, M.D. Anderson's Odyssey Scholar Program, the Department of Defense's Breast Cancer Research Program, the David and Lucille Packard Foundation, the Gillson-Longenbaugh Foundation, the Marcus Foundation, AngelWorks, the National Institutes of Health and the National Cancer Institute.


For more info visit http://www.nsf.gov

Expedition 24 Set for a Launch to Station on June 15

Expedition 24 Flight Engineer Tracy Caldwell Dyson talked to the ESPN2 network Thursday on the eve of the World Cup opening matches in Johannesburg, South Africa. She also talked with students at the Cradle of Aviation Museum in Garden City, N.Y. Caldwell Dyson talked about her perspective of Earth from space and discussed living and working on the International Space Station.

Commander Alexander Skvortsov and Flight Engineer Mikhail Kornienko continued their science and maintenance activities in the Russian segment of the orbital laboratory. They checked and replaced filters and downloaded space radiation readings from a dosimeter.

Back on Earth, two astronauts and a cosmonaut are preparing to join Expedition 24. Flight Engineers Doug Wheelock, Shannon Walker and Fyodor Yurchikhin are in Kazakhstan readying for their launch aboard the Soyuz TMA-19 spacecraft on Tuesday at 5:35 p.m. EDT.

The new station crew members will arrive and dock to the aft end of the Zvezda service module on Thursday at 6:25 p.m. Ten days later Wheelock, Walker and Yurchikhin will relocate the Soyuz TMA-19 vehicle from Zvezda to the Rassvet Mini-Research Module. The Rassvet is the station’s newest module, and this will be the first time a spacecraft will dock there.

NASA on Arctic Voyage to Probe Ocean, Climate Changes

NASA’s first dedicated oceanographic field campaign goes to sea next week to take an up-close look at how changing conditions in the Arctic are affecting the ocean’s chemistry and ecosystems that play a critical role in global climate change.

The ICESCAPE mission, which stands for "Impacts of Climate on Ecosystems and Chemistry of the Arctic Pacific Environment," will investigate the impacts of climate change on the ecology and biogeochemistry of the Chukchi and Beaufort seas along Alaska's northern coast. ICESCAPE takes to sea onboard the U.S. Coast Guard Cutter Healy, the United States’ newest and most technologically advanced polar icebreaker. The Healy conducts a wide range of research activities and is designed to break four-and-a-half feet of ice continuously at three knots.

A key focus of the mission is how changes in the Arctic may be altering the ocean’s ability to absorb carbon from the atmosphere. The greenhouse gas carbon dioxide is a leading cause of global warming.

Predictions of future climate change depend on knowing the details of how this carbon cycle works in different parts of the world. NASA’s Earth science program conducts research into the global Earth system using satellite observations. Identifying how Earth's ecology and chemistry are influenced by natural processes and by humans is a key part of this research.

The Arctic Ocean, unlike other oceans, is almost completely landlocked, making it an ideal location to study ongoing climate changes in a marine ecosystem already heavily impacted by declining sea ice cover, ocean acidification, and an increase in incoming solar radiation. These changes are likely to modify the physics, biogeochemistry, and ecology of this environment in ways that are not well understood. Satellite remote sensing has provided some insight into these changes which ICESCAPE is designed to advance.

"The ocean ecosystem in the Arctic has changed dramatically in recent years, and it’s changing much faster and much more than any other ocean in the world," said ICESCAPE chief scientist Kevin Arrigo of Stanford University. "Declining sea ice in the Arctic is certainly one reason for the change, but that’s not the whole story. We need to find out, for example, where the nutrients are coming from that feed this growth if we are going to be able to predict what the future holds for this region."

The Healy leaves Dutch Harbor in Alaska's Aleutian Islands on June 15 and heads to the Bering Strait where it begins ocean sampling. The voyage continues across the southern Chukchi Sea and into the Beaufort Sea along northern Alaska’s ocean shelf. In early July the Healy will head north into deeper waters to sample thick, multi-year sea ice and take samples within and beneath the ice.

More than 40 scientists will spend five weeks at sea sampling the physical, chemical, and biological characteristics of the ocean and sea ice. A variety of instruments will be used onboard the Healy and deployed into the ocean and on the sea ice.

An automated microscope onboard will take continuous digital photographs of phytoplankton cells for near-real time observations of the quantity of different species. Floats with near-real time satellite communication will be placed in the ocean to measure temperature and various biological and optical properties. Scientists also will work on the sea ice several hundred yards from the ship to study the condition of the ice and sample the ocean ecosystem beneath it

Images Suggest Rogue Asteroid Smacked Jupiter

Without warning, a mystery object struck Jupiter on July 19, 2009, leaving a dark bruise the size of the Pacific Ocean. The spot first caught the eye of an amateur astronomer in Australia, and soon, observatories around the world, including NASA’s Hubble Space Telescope, were zeroing in on the unexpected blemish.

Astronomers had witnessed this kind of cosmic event before. Similar scars had been left behind during the course of a week in July 1994, when more than 20 pieces of Comet P/Shoemaker-Levy 9 (SL9) plunged into Jupiter’s atmosphere. The 2009 impact occurred during the same week, 15 years later.

Astronomers who compared Hubble images of both collisions say the culprit may have been an asteroid about 1,600 feet (500 meters) wide. The images, therefore, may show for the first time the immediate aftermath of an asteroid, rather than a comet, striking another planet.

The Jupiter bombardments reveal that the solar system is a rambunctious place, where unpredictable events may occur more frequently than first thought.

“This solitary event caught us by surprise, and we can only see the aftermath of the impact, but fortunately we do have the 1994 Hubble observations that captured the full range of impact phenomena, including the nature of the objects from pre-impact observations” says astronomer Heidi Hammel of the Space Science Institute in Boulder, Colo., leader of the Jupiter impact study.

"The object that hit Jupiter this time would have been small, dark, and cold—in other words, hard for us to see before the impact, regardless of which wavelength we used for observations," adds Amy Simon-Miller, a co-investigator at NASA's Goddard Space Flight Center in Greenbelt, Md.

In 2009 Hammel’s team snapped images of the debris field with Hubble’s recently installed Wide Field Camera 3 and newly repaired Advanced Camera for Surveys.

The analysis revealed key differences between the two collisions (in 1994 and 2009), providing clues to the 2009 event. Astronomers saw a distinct halo around the 1994 impact sites in Hubble ultraviolet (UV) images, evidence of fine dust arising from a comet-fragment strike. The UV images also showed a strong contrast between impact-generated debris and Jupiter’s clouds.

Hubble UV images of the 2009 impact showed no halo and also revealed that the site’s contrast faded rapidly. Both clues suggest a lack of lightweight particles, providing circumstantial evidence for an impact by a solid asteroid rather than a dusty comet.

The elongated shape of the recent impact site also differs from the 1994 strike, indicating that the 2009 object descended from a shallower angle than the SL9 fragments. The 2009 body also came from a different direction than the SL9 pieces.

The visible spectrum, however, was "nearly identical in this case to what we saw for SL9," says Simon-Miller, who recalculated the SL9 spectrum for this analysis. "This isn't surprising, because most of the debris we're looking at is actually burnt-up atmosphere: hydrogen, hydrocarbons, and soot. It's very black, just like the soot we're familiar with, and has a very flat spectrum."

By analyzing the temperatures and the spread of debris around the impact site, Simon-Miller also determined that much of the debris was located high in Jupiter's stratosphere. "Based on the temperature, we figured out how the wind changed with height," she explains. "And by looking at how the debris was moving, we figured out how high in altitude it must be."

Team member Agustín Sanchez-Lavéga of the University of the Basque Country in Bilbao, Spain, and colleagues performed an analysis of possible orbits that the 2009 impacting body could have taken to collide with Jupiter. Their work indicates the object probably came from the Hilda family of bodies, a secondary asteroid belt consisting of more than 1,100 asteroids orbiting near Jupiter.

The 2009 strike was equal to a few thousand standard nuclear bombs exploding, comparable to the blasts from the medium-sized fragments of SL9. The largest of those fragments created explosions that were many times more powerful than the world’s entire nuclear arsenal blowing up at once.

The recent impact underscores the important work performed by amateur astronomers. “This event beautifully illustrates how amateur and professional astronomers can work together,” notes Hammel.

Snow melt appear to be faster rate in Eurasia

Over the past 30 years, springtime snow melt and warming appear to be proceeding at a faster rate in Eurasia than in North America.

Climate scientist Mark Flanner, an assistant professor at the University of Michigan and a recent Advanced Study Program graduate at the National Science Foundation's (NSF) National Center for Atmospheric Research (NCAR), led a study that investigated these changes, ultimately finding that spring warming rates and snow cover decline in Eurasia may be twice what they are in North America.

In the same study, Flanner and his colleagues also pointed out that only one of the climate scenarios generated by general circulation models in the Intergovernmental Panel on Climate Change's (IPCC) Fourth Assessment Report reflected this trend.

In fact, most IPCC model scenarios show the regions having similar springtime temperatures and snow-melt rates. Flanner and his collaborators suspect aerosols--particularly black carbon and mineral dust--might be responsible for the difference in modeled versus observed climate.

Eurasia produces high levels of both types of aerosols, which blow across the Eurasian land mass and affect the surface and nearby atmosphere in a variety of ways.

Some aerosols reflect incoming solar energy, potentially cooling underlying surfaces, but black carbon and mineral dust tend to warm snow-covered surfaces by absorbing incoming solar energy. Particulates that fall to the surface also reduce snow's reflective qualities, causing even more radiation to be absorbed.

In the Northern Hemisphere, springtime snow cover is unique because of its widespread distribution, and because intense incoming solar radiation during that season amplifies atmospheric aerosols' effects.

Because higher concentrations of organic matter, black carbon and dust are typical in the atmosphere and on the snow-covered surfaces in Eurasia, Flanner and his colleagues hypothesize that those aerosols might account for regional snow-cover differences. By including these aerosols in climate models, the researchers hypothesized that the models might more effectively match springtime observations.

To test their hypothesis, the team first ran a number of modeling scenarios to see if the inconsistency might relate to ocean-based effects. If oceans proved to have a leading role, the aerosol hypothesis would likely be incorrect. However, after constraining the oceans' effects, the models continued under-predicting land-surface temperature trends. The findings indicated that a land effect likely accounts for the discrepancy between observations and models showing warming and melting trends.

Having eliminated ocean effects, the researchers enhanced the models with snow-darkening characteristics, mimicking the impact of dark materials deposited on top of pristine snow. With this adjustment, the models correctly indicated increased springtime warming in Eurasia.

Next, the researchers incorporated human-produced carbon dioxide (CO2) into the models. The scientists found that over North America, CO2 had more of an impact on springtime snow cover than black carbon and organic matter, but in Eurasia, as hypothesized, the particulates were far more influential, having nearly as much of an effect as CO2.

"While this research does not fully explain why springtime land temperatures and snow cover are changing so much faster over Eurasia than North America, it does suggest that snow darkening from black carbon, a process lacking in most climate models, is playing a role," Flanner said.

Ultimately, Flanner continues, the magnitude of Earth's climate response to CO2 and other human-generated products depends on feedbacks. Changes in snow cover amplify initial climate changes and constitute one of the most powerful feedbacks. Because snow covers much of the Northern Hemisphere during spring, Flanner and his colleagues expect to see some of the strongest climate change signals in northerly regions during local spring.

Tracking Sickness From Space

Sometimes the best way to fight sickness on Earth starts with a view from space. On Thursday, June 10, Dr. Jeff Luvall, a research scientist at NASA's Marshall Space Flight Center, will answer questions about "Tracking Sickness from Space."

Joining the chat is easy. Simply visit this page on Thursday, June 10 from 3-4 p.m. EDT. The chat window will be active at the bottom of this page starting at 2:30 p.m. EDT. See you in chat!

More About Chat Expert Jeff Luvall
Dr. Jeff Luvall, a research scientist at NASA's Marshall Space Flight Center, will be answering your questions about "Tracking Sickness from Space." Luvall has been involved with tracking a variety of health-related conditions using NASA resources -- primarily satellite imagery and data and aircraft studying atmospheric and climate conditions.

To date, Luvall has studied allergy-related conditions by tracking pollen, and documented and provided mitigation solutions for "urban heat islands," which occur when trapped heat builds up during the day in buildings, pavement and other urban surfaces, contributing to heat-related health issues. Additionally, Luvall has trained students and professionals to use NASA satellite data in improving medicine and contributing to public health.

One of his main areas of study for the last three years has been working with students researching Lyme and West Nile diseases. The populations of the vectors for these diseases (mosquitoes, ticks) are dependent on both habitat and environmental conditions that vary both in time and space, making them ideal to study using NASA based satellite technology.

Tracking Sickness From Space

Sometimes the best way to fight sickness on Earth starts with a view from space. On Thursday, June 10, Dr. Jeff Luvall, a research scientist at NASA's Marshall Space Flight Center, will answer questions about "Tracking Sickness from Space."

Joining the chat is easy. Simply visit this page on Thursday, June 10 from 3-4 p.m. EDT. The chat window will be active at the bottom of this page starting at 2:30 p.m. EDT. See you in chat!

More About Chat Expert Jeff Luvall
Dr. Jeff Luvall, a research scientist at NASA's Marshall Space Flight Center, will be answering your questions about "Tracking Sickness from Space." Luvall has been involved with tracking a variety of health-related conditions using NASA resources -- primarily satellite imagery and data and aircraft studying atmospheric and climate conditions.

To date, Luvall has studied allergy-related conditions by tracking pollen, and documented and provided mitigation solutions for "urban heat islands," which occur when trapped heat builds up during the day in buildings, pavement and other urban surfaces, contributing to heat-related health issues. Additionally, Luvall has trained students and professionals to use NASA satellite data in improving medicine and contributing to public health.

One of his main areas of study for the last three years has been working with students researching Lyme and West Nile diseases. The populations of the vectors for these diseases (mosquitoes, ticks) are dependent on both habitat and environmental conditions that vary both in time and space, making them ideal to study using NASA based satellite technology.