NASA'S Kepler Spacecraft Takes Pulse Of Distant Stars

WASHINGTON -- An international cadre of scientists that used data from NASA's Kepler spacecraft announced Tuesday the detection of stellar oscillations, or "starquakes," that yield new insights about the size, age and evolution of stars.

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

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

"Using the unparalleled data provided by Kepler, KASC scientists are quite literally revolutionizing our understanding of stars and their structures," said Douglas Hudgins, Kepler Program Scientist at NASA Headquarters in Washington. "What's more, they are doing so at no cost to the American taxpayer. All the KASC scientists are supported by research funding from their home countries. It is a perfect illustration of the tremendous value that our international partners bring to NASA missions."

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

"We are just about to enter a new area in stellar astrophysics," said Thomas Kallinger, lead author on a study of red giant stars and postdoctoral fellow at the Universities of British Columbia and Vienna. "Kepler provides us with data of such good quality that they will change our view of how stars work in detail."

KASC scientists also reported on the star RR Lyrae. It has been studied for more than 100 years as the first member of an important class of stars used to measure cosmological distances. The brightness, or light wave amplitude, of the star oscillates within a well-known period of about 13.5 hours. Yet during that period, other small cyclic changes in amplitude occur -- behavior known as the Blazhko effect.

The effect has puzzled astronomers for decades, but thanks to Kepler data, scientists may have a clue as to its origin. Kepler observations revealed an additional oscillation period that had never been previously detected. The oscillation occurs with a time scale twice as long as the 13.5-hour period. The Kepler data indicates the doubling is linked to the Blazhko effect.

"Kepler data ultimately will give us a better understanding of the future of our sun and the evolution of our galaxy as a whole," said Daniel Huber, lead author on one of the KASC studies.

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

International Partners Update Space Station Launch Manifest

WASHINGTON -- NASA, the European Space Agency (ESA) and the Russian Federal Space Agency (Roscosmos) agreed on Friday to update the International Space Station launch schedule.

The target launch dates for the last planned space shuttle flight, STS-134 on Endeavour, will be Feb. 27, 2011, and the Automated Transfer Vehicle-2 (ATV-2) will be Feb. 15. Roscosmos will continue to look at Soyuz launch and landing options to provide manifest robustness.

The agencies agreed to the changes during discussions at the International Astronautical Conference in Prague. Arianespace, whose Ariane 5 rocket will launch ATV-2 into orbit from French Guiana, has confirmed its commitment to launch on Feb. 15.

The STS-134 flight will deliver the Alpha Magnetic Spectrometer (AMS) to the station. The AMS is a state-of-the-art cosmic ray particle physics detector designed to examine fundamental issues about matter, and the origin and structure of the universe. The flight will include three spacewalks and the installation of the AMS to the exterior of the space station using both the shuttle and station arms.

ATV-2, dubbed Johannes Kepler, is scheduled to dock on Feb. 26 to the station. The cargo craft is designed to deliver more than seven tons of experiments, fuel, water, food and other supplies to the space station. While docked, ATV-2 will use its thrusters to periodically boost the station's orbit, which decays with time. It also can be used for emergency maneuvers, such as those required if a piece of space debris is predicted to hit the station. This capability saves critical attitude control propellant for the station.

After about 3.5 months, the ATV-2 will undock from the station and burn up harmlessly in the atmosphere over an uninhabited area of the Pacific Ocean. The first ATV, Jules Verne, was launched in March 2008 and reentered the atmosphere in September 2008.

The space station launch manifest is available at:


http://www.nasa.gov/mission_pages/station/structure/iss_manifest.html

For details about upcoming shuttle missions and crews, visit:


http://www.nasa.gov/shuttle

For more information about ATV-2, visit ESA at:


http://www.esa.int/SPECIALS/ATV/

For more information about the Ariane 5 launch vehicle, visit:


http://www.arianespace.com/launch-services/launch-services-overview.asp

For more information about the space station, visit:


http://www.nasa.gov/station

Five Things About NASA's Mars Curiosity Rover

Mars Science Laboratory, aka Curiosity, is part of NASA's Mars Exploration Program, a long-term program of robotic exploration of the Red Planet. The mission is scheduled to launch from Cape Canaveral, Fla., in late 2011, and arrive at an intriguing region of Mars in August 2012.

The goal of Curiosity, a rolling laboratory, is to assess whether Mars ever had an environment capable of supporting microbial life and conditions favorable for preserving clues about life, if it existed. This will help us better understand whether life could have existed on the Red Planet and, if so, where we might look for it in the future.

1. How Big Is It?: The Mini Cooper-sized rover is much bigger than its rover predecessors, Spirit, Opportunity and Pathfinder. Curiosity is twice as long (about 2.8 meters, or 9 feet) and four times as heavy as Spirit and Opportunity, which landed in 2004. Pathfinder, about the size of a microwave oven, landed in 1997.
2. Landing--Where and How: In November 2008, possible landing sites were narrowed to four finalists, all linked to ancient wet conditions. NASA will select a site believed to be among the most likely places to hold a geological record of a favorable environment for life. The site must also meet safe-landing criteria. The landing system is similar to a sky crane heavy-lift helicopter. After a parachute slows the rover's descent toward Mars, a rocket-powered backpack will lower the rover on a tether during the final moments before landing. This method allows landing a very large, heavy rover on Mars (instead of the airbag landing systems of previous Mars rovers). Other innovations enable a landing within a smaller target area than previous Mars missions.
   
   
3. Toolkit: Curiosity will use 10 science instruments to examine rocks, soil and the atmosphere. A laser will vaporize patches of rock from a distance, and another instrument will search for organic compounds. Other instruments include mast-mounted cameras to study targets from a distance, arm-mounted instruments to study targets they touch, and deck-mounted analytical instruments to determine the composition of rock and soil samples acquired with a powdering drill and a scoop.
   
   
4. Big Wheels: Each of Curiosity's six wheels has an independent drive motor. The two front and two rear wheels also have individual steering motors. This steering allows the rover to make 360-degree turns in-place on the Mars surface. The wheels' diameter is double the wheel diameter on Spirit and Opportunity, which will help Curiosity roll over obstacles up to 75 centimeters (30 inches) high.
   
   
5. Rover Power: A nuclear battery will enable Curiosity to operate year-round and farther from the equator than would be possible with only solar power.
   

Source NASA

NASA Data Track Seasonal Pollution Changes Over India

Data from the Multi-angle Imaging Spectroradiometer (MISR) instrument on NASA's Terra spacecraft have been used in a groundbreaking new university study that examines the concentration, distribution and composition of aerosol pollution over the Indian subcontinent. The study documents the region's very high levels of natural and human-produced pollutants, and uncovered surprising seasonal shifts in the source of the pollution.

Larry Di Girolamo and postdoctoral scientist Sagnik Dey of the University of Illinois, Champaign, used a decade's worth of MISR data to comprehensively analyze aerosol pollution over the Indian subcontinent. This densely populated region has poor air quality and lacks on-the-ground pollution monitoring sites. The study was published recently in the Journal of Geophysical Research.

Aerosols — tiny particles suspended in the air — are produced both by natural sources, such as dust and pollen carried on the wind, and by human activities, such as soot and other hydrocarbons released from the burning of fossil fuels. They can affect the environment and human health, causing a range of respiratory problems. Aerosol pollution levels can be measured on the ground, but only the most developed countries have widespread sensor data.

Since standard satellite imaging cannot measure aerosols over land, Di Girolamo and Dey used NASA's MISR, developed and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. MISR's unique multi-view design allows researchers to differentiate surface variability from the atmosphere so they can observe and quantitatively measure particles in the air.

MISR not only measures the amount of aerosols, but can also distinguish between natural and human-produced particles.
The scientists found very high levels of both natural and human-produced aerosol pollutants. The level of atmospheric pollution across most of the country was two to five times higher than World Health Organization guidelines.

But the study also revealed some surprising trends. For example, the researchers noticed consistent seasonal shifts in human-produced versus natural aerosols. Before monsoon season begins, the winds over the Indian subcontinent shift, blowing inland instead of out to sea. These winds carry immense amounts of dust from Africa and the Arabian Peninsula to India, degrading air quality.

"Just before the rains come, the air gets really polluted, and for a long time everyone blamed the dust," Di Girolamo said, "but MISR has shown that not only is there an influx of dust, there's also a massive buildup of man-made pollutants that's hidden within the dust."

During monsoon season, rains wash some of the dust and soot from the air, but other human-produced pollutants continue to build up. After monsoon season, dust transport is reduced, but human-produced pollutant levels skyrocket, as biomass burning and the use of diesel-fueled transportation soar. During winter, seaward-blowing breezes disperse all the pollutants across the subcontinent and out to sea, where they remain until the pre-monsoon winds blow again.

"We desperately needed these observations to help validate our atmospheric models," said Di Girolamo. "We're finding that in a complex area like India, we have a long way to go. But these observations help give us some guidance."
As MISR continues to collect worldwide aerosol data, Di Girolamo says atmospheric scientists will continue to refine models for India and other areas and begin to propose new regulatory measures. The MISR data may also reveal trends in aerosol concentration over time, which can be compared with climate and health data.

For further information, read the complete University of Illinois news release at: http://www.news.illinois.edu/news/10/0907aerosol_DiGirolamo.html .
For more on MISR, visit: http://www-misr.jpl.nasa.gov/ .
Source NASA

NASA's HIRAD Instrument to Provide Unique View of Hurricane Wind Speeds

taken by the crew of the International Space Station

Scientists examine the inner workings of HIRAD. HIRAD is small, lightweight, relatively inexpensive, and has no moving parts, giving it a big advantage as it flies through hurricanes.

 

NASA researchers are furiously preparing for late summer when they will fly a series of unique hurricane instruments, including a brand new instrument that will take two-dimensional wind speed measurements over some of the world's fiercest storms.

The instrument will be part of a six-week NASA mission to study tropical cyclones beginning Aug. 15. The Genesis and Rapid Intensification Processes mission, or GRIP, will study the creation and rapid intensification of hurricanes. The campaign involves three planes with 15 instruments that will work together to create the most complete view of hurricanes to date.

HIRAD is mounted for testing in an anechoic chamber, a chamber outfitted with foam spikes to eliminate all ambient microwaves so that scientists can properly test the instrument.

Scientists and engineers at NASA's Marshall Space Flight Center in Huntsville, Ala. along with their partners from across the country have built the Hurricane Imaging Radiometer, HIRAD for short, to contribute to the effort. HIRAD will help determine the strength and structure of hurricanes by looking at wind speeds deep within the storm. This August and September, HIRAD will fly in the belly of a WB-57 airplane at about 60,000 feet, about twice the altitude of a commercial airliner.

Researchers across the world, including scientists at National Oceanic and Atmospheric Administration (NOAA) who have joined in HIRAD's development, hope it will provide key insight into some of nature's most puzzling questions. By allowing researchers to measure wind speeds inside the storm, HIRAD will give scientists some clues about why hurricanes behave like they do.

"The main thing we hope to do is improve the forecasts of intensity of a hurricane. Will it intensify? Will it maintain its intensity? Will it weaken? That's the hardest part of predicting hurricanes," says Dr. Tim Miller, HIRAD principal investigator and atmospheric scientist at the Marshall Center. "Of course, all science is incremental, but HIRAD hopes to make a fairly strong improvement to such forecasting."

Better predictions mean better preparations. Better predictions help people figure out when to evacuate, and when not to, as poor predictions and false alarms cost millions of dollars. More importantly, accurate forecasting builds credibility with the public so that they take evacuation warnings seriously.

HIRAD collects wind speed data by using a large antenna to measure the activity on the ocean's surface. The antenna is similar to a common radio antenna, but instead of detecting radio waves from a manufactured transmitter, it measures microwaves emitted from the ocean surface. As winds move across the surface of the sea they generate white, frothy foam. That sea foam causes the ocean surface to emit increasingly large amounts of microwave radiation, similar to the type of energy emitted by a typical home microwave oven. HIRAD captures that microwave energy and, in doing so, allows scientists to deduce how powerfully the wind is blowing.

Using the information provided by HIRAD, along with lots of other data, scientists can construct a more complete and detailed representation of the hurricane.

"We get lots of little pieces of information to figure out what's happening inside the storm," Miller explains. "We combine HIRAD's data with information from weather balloons, weather satellites and other instruments flying in the hurricane campaign, we put it all together, and we can potentially predict how a hurricane will behave."

HIRAD, measures not only directly under the plane, but also out to each side. "You can imagine if we just got a single line of measurements, we wouldn't see the full image of the wind speed. But because of HIRAD's design, we get the full two-dimensional picture," explains Miller. "Even though we're only measuring the ocean’s surface, computer models can take that information and use it to help develop a three-dimensional structure of the hurricane."

Designing and building HIRAD hasn't been easy. Engineers had to find the perfect materials to insulate the antenna elements and form the elements into the precise sizes and shapes that capture microwaves at the exact frequencies required. Fortunately, the HIRAD team's hard work is paying off. A successful flight in early 2010 revealed HIRAD is prepared to fly in NASA's upcoming study of hurricanes. Because a single flaw could mean failure, the HIRAD team works daily to keep the instrument in good shape and to reduce the risk of any problems that might arise.

During the hurricane study, HIRAD and the other instruments will likely fly several times over major storms in the Gulf of Mexico and Atlantic. Each mission will last roughly six hours, and Miller and his team from Marshall, NOAA, and the University of Michigan will monitor incoming data from the ground. Once the plane lands, the team will pull the remaining data from the plane and began their analysis.

For Miller, it's a fascinating challenge.

"I've always been interested in science. I grew up on a farm in Ohio, always saw the weather changing, and couldn't help but wonder why," he chuckles. "Hurricanes are big and complex, and a pretty challenging problem for someone who likes to understand how things work, why they do what they do."

After this fall's study, HIRAD will continue to fly in hurricane campaigns. The instrument has already been drafted for use in the Hurricane and Severe Storm Sentinel study that starts in 2011 and lasts for five years. But for now, Miller looks forward in anticipation to HIRAD's virgin flight this August.

"We're approaching it with enthusiasm and caution. If the storms are there, we need to get as much data from them as we can," he says. "Our fingers are crossed." If all goes well, HIRAD will have completed its first mission by late September. Once the flight is over, researchers will start to pore over and analyze the data. It will require countless hours of work, but the potential payoff is enormous.

The instrument will fly on a WB-57 based at Ellington Field in Houston. The WB-57 is one of the few aircraft capable of operating at 60,000 feet, an altitude so high that the pilots have to wear special pressurized suits to withstand the harsh conditions

For now, Miller and his team are looking forward to the HIRAD's voyage with excitement and anticipation. Hopefully, HIRAD's journey will put NASA researchers one step closer to understanding some of the most powerful storms in the world.

For more information about the GRIP field experiment, visit:


http://www.nasa.gov/grip

 

 

Source NASA

Chandra Finds Evidence for Stellar Cannibalism

Evidence that a star has recently engulfed a companion star or a giant planet has been found using NASA's Chandra X-ray Observatory. The likely existence of such a "cannibal" star provides new insight into how stars and the planets around them may interact as they age.

The star in question, known as BP Piscium (BP Psc), appears to be a more evolved version of our Sun, but with a dusty and gaseous disk surrounding it. A pair of jets several light years long blasting out of the system in opposite directions has also been seen in optical data. While the disk and jets are characteristics of a very young star, several clues -- including the new results from Chandra -- suggest that BP Psc is not what it originally appeared to be.

Instead, astronomers have suggested that BP Psc is an old star in its so-called red giant phase. And, rather than being hallmarks of its youth, the disk and jets are, in fact, remnants of a recent and catastrophic interaction whereby a nearby star or giant planet was consumed by BP Psc.

When stars like the Sun begin to run of nuclear fuel, they expand and shed their outer layers. Our Sun, for example, is expected to swell so that it nearly reaches or possibly engulfs Earth, as it becomes a red giant star.

"It appears that BP Psc represents a star-eat-star Universe, or maybe a star-eat-planet one," said Joel Kastner of the Rochester Institute of Technology, who led the Chandra study. "Either way, it just shows it's not always friendly out there."

Several pieces of information have led astronomers to rethink how old BP Psc might be. First, BP Psc is not located near any star-forming cloud, and there are no other known young stars in its immediate vicinity. Secondly, in common with most elderly stars, its atmosphere contains only a small amount of lithium. Thirdly, its surface gravity appears to be too weak for a young star and instead matches up with one of an old red giant.

Chandra adds to this story. Young, low-mass stars are brighter than most other stars in X-rays, and so X-ray observations can be used as a sign of how old a star may be. Chandra does detect X-rays from BP Psc, but at a rate that is too low to be from a young star. Instead, the X-ray emission rate measured for BP Psc is consistent with that of rapidly rotating giant stars.

The spectrum of the X-ray emission -- that is how the amount of X-rays changes with wavelength -- is consistent with flares occurring on the surface of the star, or with interactions between the star and the disk surrounding it. The magnetic activity of the star itself might be generated by a dynamo caused by its rapid rotation. This rapid rotation can be caused by the engulfment process.

"It seems that BP Psc has been energized by its meal," said co-author Rodolfo (Rudy) Montez Jr., also from the Rochester Institute of Technology.

The star's surface is obscured throughout the visible and near-infrared bands, so the Chandra observation represents the first detection at any wavelength of BP Psc itself.

"BP Psc shows us that stars like our Sun may live quietly for billions of years," said co-author David Rodriguez from UCLA, "but when they go, they just might take a star or planet or two with them."

Although any close-in planets were presumably devastated when BP Psc turned into a giant star, a second round of planet formation might be occurring in the surrounding disk, hundreds of millions of years after the first round. A new paper using observations with the Spitzer Space Telescope has reported possible evidence for a giant planet in the disk surrounding BP Psc. This might be a newly formed planet or one that was part of the original planetary system.

"Exactly how stars might engulf other stars or planets is a hot topic in astrophysics today," said Kastner. "We have many important details that we still need to work out, so objects like BP Psc are really exciting to find."

These results appeared in The Astrophysical Journal Letters. Other co-authors on the study were Nicolas Grosso of the University of Strasbourg, Ben Zuckerman from UCLA, Marshall Perrin from the Space Telescope Science Institute, Thierry Forveille of the Grenoble Astrophysics Laboratory in France and James Graham from University of California, Berkeley.

NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

More information, including images and other multimedia, can be found at:


http://chandra.harvard.edu

 

Source NASA

A Snapshot of Sea Ice

The Arctic Ocean is covered by a dynamic layer of sea ice that grows each winter and shrinks each summer, reaching its yearly minimum size each fall. While the 2010 minimum remains to be seen, NASA's Aqua satellite captured this snapshot on Sept. 3.

How does the Aqua satellite "see" sea ice? Microwaves. Everything on Earth’s surface -- including people -- emits microwave radiation, the properties of which vary with the emitter, thereby allowing the AMSR-E microwave sensor on Aqua to map the planet.

Ice emits more microwave radiation than water, making regions of the ocean with floating ice appear much brighter than the open ocean to the AMSR-E sensor. This difference allows the satellite to capture a sea ice record year-round, through cloud cover and the months of polar night. Continuous records are important because sea ice is dynamic. Besides melting and freezing, the ice moves with wind and currents which can cause it to split or pile up.

"The data from AMSR-E and other NASA satellites are critical for understanding the coupling between sea ice and the ocean and atmosphere," said Tom Wagner, Cryosphere program manager at NASA Headquarters in Washington. "It’s important for us to understand these connections to improve our predictive models of how the planet will change."

The Arctic sea ice is a major factor in the global climate system. The ice cools the planet by reflecting sunlight back into space. It also helps drive ocean circulation by converting the warm Pacific water that flows into the Arctic into the cold, saltier water that empties into the Atlantic. The sea ice also fundamentally shapes the Arctic; defining the organisms that make up its ecosystem and keeping heat from the ocean from melting the frozen tundra.

In fall 2009, Arctic sea ice reached its minimum extent on about Sept. 12, and was the third lowest since satellite microwave measurements were first made in 1979. Researchers are interested in year-to-year changes, which can be highly variable, so that scientists need many years, even decades, of data to examine long-term trends. Notably, all of the major minimums have occurred in the last decade, consistent with other NASA research, which shows January 2000 to December 2009 was the warmest decade on record.

As the sea ice nears the 2010 minimum later this month, look for images and analysis from NASA and the National Snow and Ice Data Center, in Boulder, Colo.

Source NASA

Deadly Tides Mean Early Exit for Hot Jupiters

Bad news for planet hunters: most of the "hot Jupiters" that astronomers have been searching for in star clusters were likely destroyed long ago by their stars. In a paper accepted for publication by the Astrophysical Journal, John Debes and Brian Jackson of NASA's Goddard Space Flight Center in Greenbelt, Md., offer this new explanation for why no transiting planets (planets that pass in front of their stars and temporarily block some of the light) have been found yet in star clusters. The researchers also predict that the planet hunting being done by the Kepler mission is more likely to succeed in younger star clusters than older ones.

"Planets are elusive creatures," says Jackson, a NASA Postdoctoral Program fellow at Goddard, "and we found another reason that they're elusive."

When astronomers began to search for planets in star-packed globular clusters about 10 years ago, they hoped to find many new worlds. One survey of the cluster called 47 Tucanae (47 Tuc), for example, was expected to find at least a dozen planets among the roughly 34,000 candidate stars. "They looked at so many stars, people thought for sure they would find some planets," says Debes, a NASA Postdoctoral Program fellow at Goddard. "But they didn't."

More than 450 exoplanets (short for "extrasolar planets," or planets outside our solar system) have been found, but "most of them have been detected around single stars," Debes notes.

"Globular clusters turn out to be rough neighborhoods for planets," explains Jackson, "because there are lots of stars around to beat up on them and not much for them to eat." The high density of stars in these clusters means that planets can be kicked out of their solar systems by nearby stars. In addition, the globular clusters surveyed so far have been rather poor in metals (elements heavier than hydrogen and helium), which are the raw materials for making planets; this is known as low metallicity.

Debes and Jackson propose that hot Jupiters—large planets that are at least 3 to 4 times closer to their host stars than Mercury is to our sun—are quickly destroyed. In these cramped orbits, the gravitational pull of the planet on the star can create a tide—that is, a bulge—on the star. As the planet orbits, the bulge on the star points a little bit behind the planet and essentially pulls against it; this drag reduces the energy of the planet's orbit, and the planet moves a little closer to the star. Then the bulge on the star gets bigger and saps even more energy from the planet's orbit. This continues for billions of years until the planet crashes into the star or is torn apart by the star's gravity, according to Jackson's model of tidal orbital decay.

"The last moments for these planets can be pretty dramatic, as their atmospheres are ripped away by their stars' gravity," says Jackson. "It has even been suggested recently the hot Jupiter called WASP-12B is close enough to its star that it is currently being destroyed."

Debes and Jackson modeled what would have happened in 47 Tuc if the tidal effect were unleashed on hot Jupiters. They recreated the range of masses and sizes of the stars in that cluster and simulated a likely arrangement of planets. Then they let the stars' tides go to work on the close-in planets. The model predicted that so many of these planets would be destroyed, the survey would come up empty-handed. "Our model shows that you don't need to consider metallicity to explain the survey results," says Debes, "though this and other effects will also reduce the number of planets."

Ron Gilliland, who is at the Space Telescope Science Institute in Baltimore and participated in the 47 Tuc survey, says, "This analysis of tidal interactions of planets and their host stars provides another potentially good explanation—in addition to the strong correlation between metallicity and the presence of planets—of why we failed to detect exoplanets in 47 Tuc."

In general, Debes and Jackson's model predicts that one-third of the hot Jupiters will be destroyed by the time a cluster is a billion years old, which is still juvenile compared to our solar system (about 4-1/2 billion years old). 47 Tuc has recently been estimated to be more than 11 billion years old. At that age, the researchers expect more than 96% of the hot Jupiters to be gone.

The Kepler mission, which is searching for hot Jupiters and smaller, Earth-like planets, gives Debes and Jackson a good chance to test their model. Kepler will survey four open clusters—groups of stars that are not as dense as globular clusters—ranging from less than half a billion to nearly 8 billion years old, and all of the clusters have enough raw materials to form significant numbers of planets, Debes notes. If tidal orbital decay is occurring, Debes and Jackson predict, Kepler could find up to three times more Jupiter-sized planets in the youngest cluster than in the oldest one. (An exact number depends on the brightness of the stars, the planets' distance from the stars, and other conditions.)

"If we do find planets in those clusters with Kepler," says Gilliland, a Kepler co-investigator, "looking at the correlations with age and metallicity will be interesting for shaping our understanding of the formation of planets, as well as their continued existence after they are formed."

If the tidal orbital decay model proves right, Debes adds, planet hunting in clusters may become even harder. "The big, obvious planets may be gone, so we'll have to look for smaller, more distant planets," he explains. "That means we will have to look for a much longer time at large numbers of stars and use instruments that are sensitive enough to detect these fainter planets."

The Kepler mission is managed by NASA's Ames Research Center, Moffett Field, Calif., for the Science Mission Directorate at NASA Headquarters in Washington.

Source NASA

NASA Data Shed New Light About Water and Volcanoes on Mars

PASADENA, Calif. -- Data from NASA's Phoenix Mars Lander suggest liquid water has interacted with the Martian surface throughout the planet's history and into modern times. The research also provides new evidence that volcanic activity has persisted on the Red Planet into geologically recent times, several million years ago.

Although the lander, which arrived on Mars on May 25, 2008, is no longer operating, NASA scientists continue to analyze data gathered from that mission. These recent findings are based on data about the planet's carbon dioxide, which makes up about 95 percent of the Martian atmosphere.

"Atmospheric carbon dioxide is like a chemical spy," said Paul Niles, a space scientist at NASA's Johnson Space Center in Houston. "It infiltrates every part of the surface of Mars and can indicate the presence of water and its history."
Phoenix precisely measured isotopes of carbon and oxygen in the carbon dioxide of the Martian atmosphere. Isotopes are variants of the same element with different atomic weights. Niles is lead author of a paper about the findings published in Thursday's online edition of the journal Science. The paper explains the ratios of stable isotopes and their implications for the history of Martian water and volcanoes.

"Isotopes can be used as a chemical signature that can tell us where something came from, and what kinds of events it has experienced," Niles said.
This chemical signature suggests that liquid water primarily existed at temperatures near freezing and that hydrothermal systems similar to Yellowstone's hot springs have been rare throughout the planet's past. Measurements concerning carbon dioxide showed Mars is a much more active planet than previously thought. The results imply Mars has replenished its atmospheric carbon dioxide relatively recently, and the carbon dioxide has reacted with liquid water present on the surface.

Measurements were performed by an instrument on Phoenix called the Evolved Gas Analyzer. The instrument was capable of doing more accurate analysis of carbon dioxide than similar instruments on NASA's Viking landers in the 1970s. The Viking Program provided the only previous Mars isotope data sent back to Earth.

The low gravity and lack of a magnetic field on Mars mean that as carbon dioxide accumulates in the atmosphere, it will be lost to space. This process favors loss of a lighter isotope named carbon-12 compared to carbon-13. If Martian carbon dioxide had experienced only this process of atmospheric loss without some additional process replenishing carbon-12, the ratio of carbon-13 to carbon-12 would be much higher than what Phoenix measured. This suggests the Martian atmosphere recently has been replenished with carbon dioxide emitted from volcanoes, and volcanism has been an active process in Mars' recent past.

However, a volcanic signature is not present in the proportions of two other isotopes, oxygen-18 and oxygen-16, found in Martian carbon dioxide. The finding suggests the carbon dioxide has reacted with liquid water, which enriched the oxygen in carbon dioxide with the heavier oxygen-18.

Niles and his team theorize this oxygen isotopic signature indicates liquid water has been present on the Martian surface recently enough and abundantly enough to affect the composition of the current atmosphere. The findings do not reveal specific locations or dates of liquid water and volcanic vents, but recent occurrences of those conditions provide the best explanations for the isotope proportions.

The Phoenix mission was led by principal investigator Peter H. Smith of the University of Arizona in Tucson, with project management at NASA's Jet Propulsion Laboratory in Pasadena, Calif. JPL is a division of the California Institute of Techology in Pasadena. The University of Arizona provided the lander's Thermal and Evolved Gas Analyzer.

For more information about the Phoenix mission, visit http://www.nasa.gov/phoenix .

source NASA

Opportunity Rover Reaches Halfway Point of Long Trek

A part of land scape took by rover in Mars

When NASA's Mars Exploration Rover Opportunity left Victoria Crater two years ago this month, the rover science team chose Endeavour Crater as the rover's next long-term destination.

With a drive of 111 meters (364 feet) on Monday, Sept. 8, Opportunity reached the estimated halfway point of the approximately 19-kilometer (11.8-mile) journey from Victoria to the western rim of Endeavour.

Opportunity completed its three-month prime mission on Mars in April 2004. During its bonus extended operations since then, it spent two years exploring in and around Victoria Crater. Victoria is about 800 meters (half a mile) in diameter. At about 22 kilometers (14 miles) in diameter, Endeavour is about 28 times wider.

After the rover science team selected Endeavour as a long-term destination, observations of Endeavour's rim by NASA's Mars Reconnaissance Orbiter revealed the presence of clay minerals. This finding makes the site an even more compelling science destination. Clay minerals, which form exclusively under wet conditions, have been found extensively on Mars from orbit, but have not been examined on the surface.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for the NASA Science Mission Directorate, Washington. For more about the twin rovers Spirit and Opportunity, see http://marsrovers.jpl.nasa.gov.

Source NASA

Two Asteroids to Pass by Earth Wednesday

PASADENA, Calif. – Two asteroids, several meters in diameter and in unrelated orbits, will pass within the moon's distance of Earth on Wednesday, Sept. 8.

Both asteroids should be observable near closest approach to Earth with moderate-sized amateur telescopes. Neither of these objects has a chance of hitting Earth. A 10-meter-sized near-Earth asteroid from the undiscovered population of about 50 million would be expected to pass almost daily within a lunar distance, and one might strike Earth's atmosphere about every 10 years on average.

The Catalina Sky Survey near Tucson, Ariz., discovered both objects on the morning of Sunday, Sept. 5, during a routine monitoring of the skies. The Minor Planet Center in Cambridge, Mass., first received the observations Sunday morning, determined preliminary orbits and concluded that both objects would pass within the distance of the moon about three days after their discovery.

Near-Earth asteroid 2010 RX30 is estimated to be 32 to 65 feet (10 to 20 meters) in size and will pass within 0.6 lunar distances of Earth (about 154,000 miles, or 248,000 kilometers) at 2:51 a.m. PDT (5:51 a.m. EDT) Wednesday. The second object, 2010 RF12, estimated to be 20 to 46 feet (6 to 14 meters) in size, will pass within 0.2 lunar distances (about 49,088 miles or 79,000 kilometers) a few hours later at 2:12 p.m. PDT (5:12 pm EDT).

More information about asteroids is available at http://www.jpl.nasa.gov/asteroidwatch/ . You can also follow the latest news about asteroids on Twitter at @asteroidwatch .

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NASA Sensors to Guide Spacecraft to Safe, Distant Landings

NASA is developing technologies that will allow landing vehicles to automatically identify and navigate to the location of a safe landing site while detecting landing hazards during the final descent to the surface. This is important because future missions -- whether to the Moon, an asteroid, Mars or other location -- will need this capability to land safely near specific resources that are located in potentially hazardous terrain.

Langley Research Center, Hampton, Va., has designed three light detection and ranging (lidar) sensors that together can provide all the necessary data for achieving safe autonomous precision landing.

One is a three-dimensional active imaging device, referred to as flash lidar, for detecting hazardous terrain features and identifying safe landing sites. The second is a Doppler lidar instrument for measuring the vehicle velocity and altitude to help land precisely at the chosen site. The third is a high-altitude laser altimeter providing data prior to final approach for correcting the flight trajectory towards the designated landing area.

 In conjunction with laser/lidar sensor development at Langley, NASA's Jet Propulsion Laboratory, Pasadena, Calif., is developing algorithms, or mathematical procedures, for analyzing the acquired three-dimensional lidar maps and determining the most suitable landing site. The resulting Doppler lidar and laser altimeter data are used by the navigation system being developed by NASA Johnson Space Center, Houston, and Charles Draper Laboratory, Cambridge, Mass., to control the spacecraft to the identified location.

These technologies have been integrated as part of NASA's Autonomous Landing and Hazard Avoidance Technology (ALHAT) project and are in the process of being demonstrated in a series of flight tests.

The most recent flight tests occurred at NASA's Dryden Flight Research Center, Edwards, Calif., in July.

"These were the first tests where we had all three of our laser systems on board and working together as a complete sensor suite," said Langley's Farzin Amzajerdian, technical lead for development of the sensors. "These tests are being viewed as critical by many within NASA."

Robert Reisse, Langley project manager, added, "We were pleased that the flight tests we've conducted so far have resulted in better than expected performance of these sensors."

The main objective of the first test, carried out in May 2008, was to demonstrate the application of 3-D imaging technology, or 'flash' lidar, for topography mapping and hazard detection.

The second round of flight tests, completed in August 2008, was to evaluate the capabilities of the Doppler lidar. This lidar provides high reliability vehicle velocity vector, altitude and attitude with about two orders of magnitude higher precision than radars.


The third flight test campaign was conducted in June 2009 in which the flash lidar and laser altimeter were integrated and flown onboard a fixed-wing aircraft to assess its performance for terrain relative navigation and altimetry functions. Several flights were performed in areas of Death Valley and in the Nevada Test Site with various flight profiles and altitudes reaching more than five miles above ground level. Locations were selected primarily because of topographical similarities to the lunar terrain.

For the most recent field test, a Sikorsky S-64 helicopter carried all three lidar systems in a pod along with their support instruments. The flash lidar was mounted on a gimbal controlled by the ALHAT processor box that included a navigation filter built specifically for ALHAT by Draper Labs and a human interface module built by NASA Johnson. The processor box also included a 3-D elevation map generator developed by NASA JPL.

NASA Johnson leads the eight-year ALHAT task, begun in early 2006, for NASA's Exploration Technology Development Program. Support is also provided by Draper Labs and the Johns Hopkins Applied Physics Laboratory, Baltimore.

H. Keith Henry
NASA Langley Research Center

Source NASA

Missing Piece Inspires New Look at Mars Puzzle

PASADENA, Calif. -- Experiments prompted by a 2008 surprise from NASA's Phoenix Mars Lander suggest that soil examined by NASA's Viking Mars landers in 1976 may have contained carbon-based chemical building blocks of life.

"This doesn't say anything about the question of whether or not life has existed on Mars, but it could make a big difference in how we look for evidence to answer that question," said Chris McKay of NASA's Ames Research Center, Moffett Field, Calif. McKay coauthored a study published online by the Journal of Geophysical Research - Planets, reanalyzing results of Viking's tests for organic chemicals in Martian soil.

The only organic chemicals identified when the Viking landers heated samples of Martian soil were chloromethane and dichloromethane -- chlorine compounds interpreted at the time as likely contaminants from cleaning fluids. But those chemicals are exactly what the new study found when a little perchlorate -- the surprise finding from Phoenix -- was added to desert soil from Chile containing organics and analyzed in the manner of the Viking tests.

"Our results suggest that not only organics, but also perchlorate, may have been present in the soil at both Viking landing sites," said the study's lead author, Rafael Navarro-González of the National Autonomous University of Mexico, Mexico City.

Organics can come from non-biological or biological sources. Many meteorites raining onto Mars and Earth for the past 5 billion years contain organics. Even if Mars has never had life, scientists before Viking anticipated that Martian soil would contain organics from meteorites.

"The lack of organics was a big surprise from the Vikings," McKay said. "But for 30 years we were looking at a jigsaw puzzle with a piece missing. Phoenix has provided the missing piece: perchlorate. The perchlorate discovery by Phoenix was one of the most important results from Mars since Viking." Perchlorate, an ion of chlorine and oxygen, becomes a strong oxidant when heated. "It could sit there in the Martian soil with organics around it for billions of years and not break them down, but when you heat the soil to check for organics, the perchlorate destroys them rapidly," McKay said.

This interpretation proposed by Navarro-González and his four co-authors challenges the interpretation by Viking scientists that Martian organic compounds were not present in their samples at the detection limit of the Viking experiment. Instead, the Viking scientists interpreted the chlorine compounds as contaminants. Upcoming missions to Mars and further work on meteorites from Mars are expected to help resolve this question.

The Curiosity rover that NASA's Mars Science Laboratory mission will deliver to Mars in 2012 will carry the Sample Analysis at Mars (SAM) instrument provided by NASA Goddard Space Flight Center, Greenbelt, Md. In contrast to Viking and Phoenix, Curiosity can rove and thus analyze a wider variety of rocks and samples. SAM can check for organics in Martian soil and powdered rocks by baking samples to even higher temperatures than Viking did, and also by using an alternative liquid-extraction method at much lower heat. Combining these methods on a range of samples may enable further testing of the new report's hypothesis that oxidation by heated perchlorates that might have been present in the Viking samples was destroying organics.

One reason the chlorinated organics found by Viking were interpreted as contaminants from Earth was that the ratio of two isotopes of chlorine in them matched the three-to-one ratio for those isotopes on Earth. The ratio for them on Mars has not been clearly determined yet. If it is found to be much different than Earth's, that would support the 1970s interpretation.

If organic compounds can indeed persist in the surface soil of Mars, contrary to the predominant thinking for three decades, one way to search for evidence of life on Mars could be to check for types of large, complex organic molecules, such as DNA, that are indicators of biological activity. "If organics cannot persist at the surface, that approach would not be wise, but if they can, it's a different story," McKay said.

The Phoenix mission was led by Principal Investigator Peter H. Smith of the University of Arizona, Tucson, with project management at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Phoenix finding of perchlorate was reported by JPL's Michael Hecht and co-authors. JPL, a division of the California Institute of Technology, Pasadena, also manages Mars Science Laboratory for the NASA Exploration Missions Directorate, Washington.

Source NASA

Spitzer Finds a Flavorful Mix of Asteroids

New research from NASA's Spitzer Space Telescope reveals that asteroids somewhat near Earth, termed near-Earth objects, are a mixed bunch, with a surprisingly wide array of compositions. Like a piñata filled with everything from chocolates to fruity candies, these asteroids come in assorted colors and compositions. Some are dark and dull; others are shiny and bright. The Spitzer observations of 100 known near-Earth asteroids demonstrate that the objects’ diversity is greater than previously thought.

The findings are helping astronomers better understand near-Earth objects as a whole -- a population whose physical properties are not well known.
"These rocks are teaching us about the places they come from," said David Trilling of Northern Arizona University, Flagstaff, lead author of a new paper on the research appearing in the September issue of Astronomical Journal. "It's like studying pebbles in a streambed to learn about the mountains they tumbled down."

After nearly six years of operation, in May 2009, Spitzer used up the liquid coolant needed to chill its infrared detectors. It is now operating in a so-called "warm" mode (the actual temperature is still quite cold at 30 Kelvin, or minus 406 degrees Fahrenheit). Two of Spitzer's infrared channels, the shortest-wavelength detectors on the observatory, are working perfectly.

One of the mission's new "warm" programs is to survey about 700 near-Earth objects, cataloguing their individual traits. By observing in infrared, Spitzer is helping to gather more accurate estimates of asteroids' compositions and sizes than what is possible with visible light alone. Visible-light observations of an asteroid won't differentiate between an asteroid that is big and dark, or small and light. Both rocks would reflect the same amount of visible sunlight. Infrared data provide a read on the object's temperature, which then tells an astronomer more about the actual size and composition. A big, dark rock has a higher temperature than a small, light one because it absorbs more sunlight.

Trilling and his team have analyzed preliminary data on 100 near-Earth asteroids so far. They plan to observe 600 more over the next year. There are roughly 7,000 known near-Earth objects out of a population expected to number in the tens to hundreds of thousands.

"Very little is known about the physical characteristics of the near-Earth population," said Trilling. "Our data will tell us more about the population, and how it changes from one object to the next. This information could be used to help plan possible future space missions to study a near-Earth object."

The data show that some of the smaller objects have surprisingly high albedos (an albedo is a measurement of how much sunlight an object reflects). Since asteroid surfaces become darker with time due to exposure to solar radiation, the presence of lighter, brighter surfaces for some asteroids may indicate that they are relatively young. This is evidence for the continuing evolution of the near-Earth object population.

In addition, the fact that the asteroids observed so far have a greater degree of diversity than expected indicates that they might have different origins. Some might come from the main belt between Mars and Jupiter, and others could come from farther out in the solar system. This diversity also suggests that the materials that went into making the asteroids -- the same materials that make up our planets -- were probably mixed together like a big solar-system soup very early in its history.

The research complements that of NASA's Wide-field Infrared Survey Explorer, or WISE, an all-sky infrared survey mission also up in space now. WISE has already observed more than 430 near-Earth objects -- of these, more than 110 are newly discovered.

In the future, both Spitzer and WISE will tell us even more about the "flavors" of near-Earth objects. This could reveal new clues about how the cosmic objects might have dotted our young planet with water and organics -- ingredients needed to kick-start life.

Other authors of the paper include Cristina Thomas, also from Northern Arizona University; Michael Mueller and Marco Delbo of the Observatoire de la Côte d'Azur, Nice, France; Joseph Hora, Giovanni Fazio, Howard Smith and Tim Spahr of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass.; Alan Harris of the DLR Institute of Planetary Research, Berlin, Germany (DLR is Germany's space agency and stands for Deutsches Zentrum für Luft- und Raumfahrt); Bidushi Bhattacharya of the NASA Herschel Science Center at the California Institute of Technology, Pasadena; Steve Chesley and Amy Mainzer of NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Bill Bottke of the Southwest Research Institute, Boulder, Colo.; Josh Emery of the University of Tennessee, Knoxville; Bryan Penprase of the Pomona College, Claremont, Calif.; and John Stansberry of the University of Arizona, Tucson.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu/ and http://www.nasa.gov/spitzer .

JPL manages the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. More information is online at http://www.nasa.gov/wise and http://wise.astro.ucla.edu .

Source NASA

 

NASA Selects Science Investigations for Solar Probe Plus

WASHINGTON -- NASA has begun development of a mission to visit and study the sun closer than ever before. The unprecedented project, named Solar Probe Plus, is slated to launch no later than 2018.

The small car-sized spacecraft will plunge directly into the sun's atmosphere approximately four million miles from our star's surface. It will explore a region no other spacecraft ever has encountered. NASA has selected five science investigations that will unlock the sun's biggest mysteries.

"The experiments selected for Solar Probe Plus are specifically designed to solve two key questions of solar physics -- why is the sun's outer atmosphere so much hotter than the sun's visible surface and what propels the solar wind that affects Earth and our solar system? " said Dick Fisher, director of NASA's Heliophysics Division in Washington. "We've been struggling with these questions for decades and this mission should finally provide those answers."

As the spacecraft approaches the sun, its revolutionary carbon-composite heat shield must withstand temperatures exceeding 2550 degrees Fahrenheit and blasts of intense radiation. The spacecraft will have an up close and personal view of the sun enabling scientists to better understand, characterize and forecast the radiation environment for future space explorers.

NASA invited researchers in 2009 to submit science proposals. Thirteen were reviewed by a panel of NASA and outside scientists. The total dollar amount for the five selected investigations is approximately $180 million for preliminary analysis, design, development and tests.

The selected proposals are:
-- Solar Wind Electrons Alphas and Protons Investigation: principal investigator, Justin C. Kasper, Smithsonian Astrophysical Observatory in Cambridge, Mass. This investigation will specifically count the most abundant particles in the solar wind -- electrons, protons and helium ions -- and measure their properties. The investigation also is designed to catch some of the particles in a special cup for direct analysis.

-- Wide-field Imager: principal investigator, Russell Howard, Naval Research Laboratory in Washington. This telescope will make 3-D images of the sun's corona, or atmosphere. The experiment actually will see the solar wind and provide 3-D images of clouds and shocks as they approach and pass the spacecraft. This investigation complements instruments on the spacecraft providing direct measurements by imaging the plasma the other instruments sample.

-- Fields Experiment: principal investigator, Stuart Bale, University of California Space Sciences Laboratory in Berkeley, Calif. This investigation will make direct measurements of electric and magnetic fields, radio emissions, and shock waves that course through the sun's atmospheric plasma. The experiment also serves as a giant dust detector, registering voltage signatures when specks of space dust hit the spacecraft's antenna.

-- Integrated Science Investigation of the Sun: principal investigator, David McComas of the Southwest Research Institute in San Antonio. This investigation consists of two instruments that will take an inventory of elements in the sun's atmosphere using a mass spectrometer to weigh and sort ions in the vicinity of the spacecraft.

-- Heliospheric Origins with Solar Probe Plus: principal investigator, Marco Velli of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Velli is the mission's observatory scientist, responsible for serving as a senior scientist on the science working group. He will provide an independent assessment of scientific performance and act as a community advocate for the mission.

"This project allows humanity's ingenuity to go where no spacecraft has ever gone before," said Lika Guhathakurta, Solar Probe Plus program scientist at NASA Headquarters, in Washington. "For the very first time, we'll be able to touch, taste and smell our sun."

The Solar Probe Plus mission is part of NASA's Living with a Star Program. The program is designed to understand aspects of the sun and Earth's space environment that affect life and society. The program is managed by NASA'S Goddard Space Flight Center in Greenbelt, Md., with oversight from NASA's Science Mission Directorate's Heliophysics Division. The Johns Hopkins University Applied Physics Laboratory in Laurel, Md., is the prime contractor for the spacecraft.


Source NASA

NASA Provides Assistance to Trapped Chilean Miners

On Aug. 5, the San José copper and gold mine near the northern town of Copiapó, Chile, collapsed, trapping 33 miners about a half mile underground. The Chilean government spoke with the United States Department of State to request NASA's technical advice related to the agency's life sciences research activities.

On Aug. 31, a NASA team of experts arrived in Santiago as part of NASA's commitment to provide U.S. assistance. NASA's assistance is only a small contribution to the Chilean government's overall rescue effort. On Sept. 1, the team began three days’ worth of meetings in Copiapó.

The NASA team includes two medical doctors, a psychologist and an engineer. Dr. Michael Duncan, deputy chief medical officer in NASA's Space Life Sciences Directorate at NASA's Johnson Space Center in Houston, is leading the team. The other team members are physician J.D. Polk, psychologist Al Holland and engineer Clint Cragg.

NASA's long experience in training and planning for emergencies in human spaceflight and its protection of humans in the hostile environment of space may have some direct benefits that can be useful to the rescue. Environments may very well be different, but human response both in physiology and behavioral responses to emergencies is quite similar. Some of the results acquired through NASA's research may be applicable to the trapped miners.

Source NASA

NASA watches Hurricanes!!

NASA Images Dissect Hurricane Earl

With the peak of the 2010 Atlantic hurricane season still 10 days away, the relative calm of the first half of the season has quickly evaporated. As of Sept. 1, there were three named tropical cyclones in the Atlantic-Hurricane Earl and Tropical Storms Fiona and Gaston.

NASA satellites, instruments and researchers are hard at work, providing the National Oceanic and Atmospheric Administration and other agencies with many kinds of data used to help forecast and track these monster storms.

The NASA imagery presented here depicts Hurricane Earl, currently a Category Four hurricane on the Saffir-Simpson scale with maximum sustained winds of 115 knots (near 135 miles per hour), with higher gusts. As of 5 p.m. EDT on Sept. 1, Earl was located about 1,010 kilometers (630 miles) south-southeast of Cape Hatteras, N.C., moving to the northwest at 28 kilometers per hour (17 mph). Hurricane and tropical storm warnings and watches currently extend up the U.S. East Coast from North Carolina to Massachusetts. Hurricane force winds extend outward up to 150 kilometers (90 miles) from Earl's center, with tropical storm-force winds extending outward up to 325 kilometers (200 miles).

Earl is expected to continue to move northwest, and then make a gradual turn to the north on Thursday, Sept. 2. The core of Earl is expected to approach the North Carolina coast by late Thursday with hurricane-force winds. Tropical-storm-force winds are likely to reach the East Coast from Virginia northward to New Jersey by early Friday, Sept. 3. Earl is expected to fluctuate in intensity through Thursday, then gradually weaken.

Earl's storm surge will raise water levels by 1 to 1.5 meters (3 to 5 feet) above ground level within the hurricane watch level. Elsewhere, the storm surge will raise water levels by as much as 0.3 to 1 meter (1 to 3 feet) above ground level within the tropical storm warning area. The storm surge will be accompanied by large and destructive waves.

Rainfall accumulations of 5 to 10 centimeters (2 to 4 inches), with isolated amounts up to 15 centimeters (6 inches) are expected over parts of eastern North Carolina. Large surf swells will continue to affect the Bahamas and U.S. East Coast through Friday, bringing dangerous surf conditions and rip currents.

NASA imagery of Earl from various satellites and aircraft reveal many kinds of information about this impressive storm.

In Figure 1, the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite, built and managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., captured this infrared image of Earl on Sept. 1 at 1:53 p.m. EDT. The AIRS data create an accurate 3-D map of atmospheric temperature, water vapor and clouds, data that are useful to hurricane forecasters. The image shows the temperature of Earl's cloud tops or the surface of Earth in cloud-free regions. The coldest cloud-top temperatures appear in purple, indicating towering cold clouds and heavy precipitation. The infrared signal of AIRS does not penetrate through clouds. Where there are no clouds, AIRS reads the infrared signal from the surface of the ocean waters, revealing warmer temperatures in orange and red.

The view of the storm for AIRS' visible-light camera is seen in Figure 2.

Figure 3 is an animation created from data from NASA's CloudSat spacecraft, which flew over Hurricane Earl on Aug. 31, 2010, at 2:20 a.m. EDT, when the storm had maximum wind speeds of 115 kilometers (approximately 135 mph). At that time, there were three named storms in the Atlantic: Danielle, Earl and Fiona.

The animation begins by depicting global cloud motion for the 72 hours prior to CloudSat's observation of Earl, from NOAA's GOES satellites. It then zooms in to reveal the vertical cross-section of Earl from CloudSat. CloudSat intersected Earl's eastern edge as the hurricane was just beginning an eyewall replacement cycle, during which the outer eyewall band strengthened, while the inner eyewall began to shrink. CloudSat captured Earl's intense cumulonimbus clouds and eye, along with cloud-free regions known as "moats" that contain a thick cirrus cloud canopy between the storm's spiral rain bands. The storm's most intense convection and precipitation are depicted in shades of oranges and reds.

Figure 4 is from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra spacecraft, captured at 11 a.m. EDT on Aug. 30, 2010, when Earl was a Category 3 storm on the Saffir-Simpson scale. The image (left panel) extends approximately 1,110 kilometers (690 miles) in the north-south direction and 380 kilometers (236 miles) in the east-west direction. The hurricane's eye is just visible on the right edge of the MISR image swath.

Winds at various altitudes were obtained by processing the data from five of MISR's nine cameras to produce the display shown on the right. The lengths of the arrows indicate the wind speeds, and their orientation shows wind direction. The altitude of a given wind vector is shown in color. Low clouds, less than 4 kilometers (2.5 miles) in altitude (shown in purple), follow the cyclonic (counter-clockwise) flow of air into the hurricane. This warm, moist air is the power source for the hurricane. Mid- and high-level clouds (green and yellow-orange, respectively) move in an anti-cyclonic (clockwise) direction as they flow out from the top of the storm. The very highest clouds, with altitudes around 17 kilometers (10.6 miles), are flowing directly away from the eye of the hurricane.

Figure 5 and Figure 6 were generated with data from NASA's Jason-1 and Ocean Surface Topography Mission (OSTM)/Jason-2 satellites. They depict Earl's wind speeds (top) and wave heights (bottom), respectively. The images were created by compositing three days of data from the two satellites' radar altimeters from Aug. 29 to Sept. 1.

NASA and JPL scientists are currently engaged in the agency's first major U.S.-based hurricane field campaign in nearly a decade. The Genesis and Rapid Intensification Processes mission, or GRIP, is studying hurricanes in the Atlantic and Gulf of Mexico. Three NASA aircraft carrying 15 instruments are being used, including the JPL-developed High-Altitude Monolithic Microwave Integrated Circuit Sounding Radiometer (HAMSR), which is flying aboard NASA's Global Hawk uninhabited aerial vehicle. The instrument infers the 3-D distribution of temperature, water vapor and cloud liquid water in the atmosphere. A second JPL instrument, the Airborne Precipitation Radar (APR-2), is a dual-frequency weather radar that is taking 3-D images of precipitation aboard NASA's DC-8 aircraft. Three NASA satellites are also playing a key role in supplying data about tropical cyclones during the mission, including the JPL- developed and managed CloudSat spacecraft and the Aqua spacecraft, which includes JPL's Atmospheric Infrared Sounder.

The DC-8, with JPL's APR-2 instrument, has already flown over Earl twice, with additional sorties planned for Sept. 1 and 2. NASA's Global Hawk is currently en route to Earl and is expected to fly over Earl for 10 to 12 hours on Sept. 2. The progress of NASA's GRIP aircraft can be followed in near-real-time when they are flying by visiting: http://grip.nsstc.nasa.gov/current_weather.html . "Click to start RTMM Classic" will download a KML file that displays in Google Earth.

Near-real-time images from HAMSR and APR-2 will be displayed on NASA's TC-IDEAS website, available at http://grip.jpl.nasa.gov . The website is a near-real-time tropical cyclone data resource developed by JPL to support the GRIP campaign. In collaboration with other institutions, it integrates data from satellites, models and direct measurements, from many sources, to help researchers quickly locate information about current and recent oceanic and atmospheric conditions. The composite images and data are updated every hour and are displayed using a Google Earth plug-in.

With a few mouse clicks, users can manipulate data and overlay multiple data sets to provide insights on storms that aren't possible by looking at single data sets alone. The data can be animated and downloaded on demand. TC-IDEAS is a component of JPL's Tropical Cyclone Information System (TCIS) website, located at: http://tropicalcyclone.jpl.nasa.gov/hurricane/ . Researchers can use the TCIS to better understand hurricane processes, improve hurricane models and plan future satellite missions.


Source NASA

NASA's Successful Ice Cloud and Land Elevation Mission Comes to an End

UPDATE: NASA’s Orbital Debris Program Office at Johnson Space Center, Houston, has reported that debris from the ICESat spacecraft fell to Earth in the Barents Sea on Monday, Aug. 30, at approximately 5 a.m. EDT.

One of NASA's orbiting sentinels is expected to return to Earth in a few days. The agency's Ice, Cloud, and land Elevation (ICESat) satellite completed a very productive scientific mission earlier this year. NASA lowered the satellite's orbit last month and then decommissioned the spacecraft in preparation for re-entry. It is estimated that the satellite will re-enter the Earth's atmosphere and largely burn up on or about August 29.

ICESat was launched in January 2003, as a three-year mission with a goal of returning science data for five years. It was the first mission of its kind –specifically designed to study Earth's polar regions with a space-based laser altimeter called the Geoscience Laser Altimeter System, or GLAS.

ICESat's lasting legacy will be its impact on the understanding of ice sheet and sea ice dynamics. The mission has led to scientific advances in measuring changes in the mass of the Greenland and Antarctic ice sheets, polar sea ice thickness, vegetation-canopy heights, and the heights of clouds and aerosols. Using ICESat data, scientists identified a network of lakes beneath the Antarctic ice sheet. ICESat introduced new capabilities, technology and methods such as the measurement of sea ice freeboard – or the amount of ice and snow that protrudes above the ocean surface - for estimating sea ice thickness.

"ICESat has been a tremendous scientific success," said Jay Zwally, ICESat's project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "It has provided detailed information on how the Earth's polar ice masses are changing with climate warming, as needed for government policy decisions. In particular, ICESat data showed that the Arctic sea ice has been rapidly thinning, which is critical information for revising predictions of how soon the Arctic Ocean might be mostly ice free in summer. It has also shown how much ice is being lost from Greenland and contributing to sea level rise. Thanks to ICESat we now also know that the Antarctic ice sheet is not losing as much ice as some other studies have shown."

The End of an Era

After seven years in orbit and 15 laser-operations campaigns, ICESat's science mission ended in February 2010 with the failure of its primary instrument. Because the spacecraft remained in operating condition, NASA's Science Mission Directorate accepted proposals for engineering tests to be performed using ICESat. These tests were completed on June 20. NASA's Earth Science Division then authorized the decommissioning of ICESat. After completing a review of decommissioning activities, the agency directed that ICESat be decommissioned by this August.

Mission flight controllers began firing ICESat's propulsion system thrusters on June 23 to lower its orbit. Thruster firings ended on July 14, safely reducing the lowest point of the spacecraft's orbit to 125 miles (200 km) above Earth's surface. The orbit has since naturally decayed. ICESat was successfully decommissioned from operations on Aug. 14. All remaining fuel on the spacecraft is now depleted, and atmospheric drag is slowly lowering ICESat's orbit until the spacecraft re-enters the Earth's atmosphere.

A statement from the Earth Science Mission Operations office summarized the achievement:

"The ICESat mission operations team is commended for its exceptional performance, working tirelessly for the past eleven years (four years of preparation and seven years of operations), overcoming several obstacles in the early years of the mission, and closing out the mission with a flawless series of orbital maneuvers before final decommissioning. The positive control maintained over the mission right to the end shows the quality and effort that went into designing, building, qualifying, launching, and operating a tremendously successful mission such as ICESat."

The Return to Planet Earth

The vast majority of ICESat will burn up in the atmosphere during re-entry. Of the spacecraft's total mass (about 2000 lbs.), only a small percent will reach the surface of Earth. Some pieces of the spacecraft, weighing collectively about 200 pounds, are expected to survive re-entry. The risk of harm coming to anyone on Earth from this debris is estimated to be very low.

ICESat was not designed to perform a controlled re-entry and is unable to provide targeting to a particular location on Earth. ICESat circles the Earth from pole to pole, so surviving debris could land almost anywhere on the planet. Due to natural variability in the near-Earth environment, a precise location of where spacecraft debris will re-enter cannot be forecast. The U.S. Space Surveillance Network is closely monitoring the orbit of ICESat during its final days and will continue to issue periodic predictions of re-entry time and location. The NASA Orbital Debris Program Office will issue re-entry information based on these predictions.

NASA and international standards for space objects re-entering Earth's atmosphere do not require controlled re-entry but do have requirements and guidelines for the maximum risk posed by debris surviving re-entry.

"The ICESat team has done a marvelous job to ensure that the spacecraft is removed as a hazard to other spacecraft and as a potential source of future orbital debris," said Nicholas L. Johnson, NASA Chief Scientist for Orbital Debris at NASA's Johnson Space Center in Houston.

The Future Looks Bright

Despite the end of ICESat's mission, NASA's observations of Earth's polar regions continue. In anticipation of the ICESat mission coming to an end, and in accordance with the National Research Council's Decadal Survey of future NASA Earth science missions, NASA has begun development of ICESat-2, planned for launch in 2015. ICESat-2 will continue the science legacy of its predecessor, and improve our understanding of Earth's dynamic polar regions with new and advanced technology.

The Operation Ice Bridge airborne mission, started in 2009, is the largest airborne survey of Earth's polar ice ever flown. The mission is designed to partially fill the data gap between the ICESat and ICESat-2 satellite missions. For the next five years, instruments on NASA aircraft will target areas of rapid change to yield an unprecedented 3-D view of Arctic and Antarctic ice sheets, ice shelves, and sea ice. Targeted information from aircraft combined with the broad and consistent coverage from satellites contribute to a more complete understanding of Earth's response to climate change, helping scientists make better predictions of what the future might hold.

Source NASA

Communicating in Space

When astronauts venture outside of a spaceship or the International Space Station, they must wear protective space suits to keep them safe from the harsh environment of space. While inside these pressurized suits, it's essential that they remain in constant communication with the rest of the crew in space as well as Mission Control Center on Earth.

While wearing the current space suits, astronauts wear a Communications Carrier Assembly (CCA), or "Snoopy Cap" — a fabric hat fitted with microphones in the ear area for listening and boom microphones in front of the mouth for speaking. These caps are worn under the helmet and visor that surround an astronaut's head.
 
NASA is in the process of completely redesigning their space suits, with the goal of creating a brand new space suit to be used starting in 2020. Redesigned and reinvented communications equipment will be an important facet of the new suit. 

Integrated Audio

NASA's Glenn Research Center in Cleveland is working on different parts of the new space suit, including communications equipment. The Exploration Technology Development Program (ETDP) is involved with testing various proposed solutions to the communications requirements within the suit.

The Communications Carrier Assembly (CCA), while effective, has some logistical drawbacks. Multiple cap sizes must be available due to the difference in astronauts' head sizes. The caps cannot be adjusted once the visor of the helmet is in place and the astronaut is in space, which means that if the microphones shift, communication quality can decrease. The boom microphones can also interfere with feeding and drinking mechanisms during long-duration spacewalks. An additional problem is that astronaut sweat can negatively interfere with the performance of the electrical and mechanical parts in the CCA.

For several years, Glenn has performed research and development on a variety of communications technologies. About six years ago, teams at Glenn began working on integrated audio solutions to support extravehicular activities, like space walks. In 2008, Glenn signed a Small Business Innovation Research (SBIR) agreement with WeVoice Inc. of Bridgewater, N.J. Together, they began developing and testing an integrated audio system that is built directly into a space helmet.

"The integrated audio system is where the microphones and earphones are removed from the Communications Carrier Assembly and integrated into the structure of the space suit itself," says Obed "Scott" Sands, an electronics engineer at Glenn, lead for Configuration II Audio under Constellation and lead for integrated audio development for the Exploration Technology Development Program (ETDP).

The new integrated audio system solves many of the issues the CCA presents. As the integrated audio system is part of the actual space suit, there are no additional parts to worry about maintaining. The microphones and earphones are built into the suit, which means there are no moving parts to disrupt an astronaut's movements or become dislodged during activity. And the integrated audio system is a universal size — no separate caps are needed for individual crew members.

Rather than one boom microphone, the new integrated audio system uses an array of microphones — currently four, but the number could increase — that are located in front of where an astronaut's mouth is while inside the helmet. The integrated audio system features cutting-edge digital signal processing which helps the microphones overcome loss of fidelity on the outbound (speaking) part of the system.

The microphone array and associated signal processing are needed in the integrated audio system to overcome decreased sound quality. Sound quality can be negatively impacted because the microphones of the integrated audio system are positioned on the inside of the helmet — farther from an astronaut's mouth. This makes the microphones more susceptible to interference from noise created inside of the suit as well as noise from vibrations of the spacesuit structure.

The current technology development approach to solving these problems involves processing signals from each element in the array, known as Multi-Channel Noise Reduction. This new filtering approach features technology adapted from video teleconferencing systems. Advanced filters are used for each of the array's channels, and additional noise reduction is used to isolate the sound of speech.

Several speakers are installed in the helmet, which are designed to focus the sound towards the astronaut's ears. These speakers also isolate other sounds so that crew members can effectively hear. This solves the issue of occasional unclear inbound communications (listening).

"This new system will provide the crew member with more freedom and increased reliability," says Terry O'Malley, an aerospace engineer and the EVA lead at Glenn. "It also provides the system designers with increased flexibility in designing the system."

Testing with a Torso

In order to assess the effectiveness of the new system, the conditions inside a space suit must be replicated. Then the integrated audio is tested by using a specialized piece of equipment that creates human speech. This equipment, shaped like a human torso, is called HATSMAN — Head and Torso Simulator. It is manufactured by Brüel & Kjær, a company based in Denmark.

"It listens like a person and talks like a person," Sands says. "It's got microphones in its ears and a speaker in its mouth, and the radiation patterns conform to international standards for mannequins that emulate human speech and hearing."

The testing involves taking advanced measurements of the noise produced by HATMSAN and received by the integrated audio system and vice versa. This anthropometric measuring helps Glenn researchers refine their design, using data created by machines that accurately represent the needs of the humans who will eventually use the completed system.

The HATMSAN at Glenn is installed in a testing tank that is carefully designed to mimic the environment inside a space suit. It is lined with acoustic absorbing foam that isolates extra noise that the tank itself might create. Then a noise source simulates the sound created by space suits, which is generated from a recording taken inside an actual space suit. Special microphones that do not create their own static pressure are installed, which take measurements without affecting the readings.

"The biggest reason we're in the tank is that we can create a static pressure environment that simulates the inside of the actual suit," says Dave Pleva (DB Consulting Group, Inc.), an IT Project Analyst at Glenn who supports audio development work for ETDP.


The tank recreates the pressure inside of the suit, not the pressure of the entirety of space — because the integrated audio system is made for use inside a helmet. The positive pressure inside a space suit is about 4.3 PSI (equivalent to about 35,000 feet altitude) so the team tests with this as its base. They also explore other variations in barometric pressure. The test rig also includes an acrylic dome to simulate the helmet. The team explores how speech and sound bounce off of the surface of the helmet.

A specialized device, called Digital Speech Level Analyzer (DSLA), provides vocal tracks for use in testing. Various utterances comprise the test speech to make it phonetically balanced — including all of the patterns and pairs that, statistically speaking, would show up in the English language. Both male and female voices are used.

"We generate a signal, it goes through an amplifier that powers the speaker in the HATSMAN, and then the array picks up the speech. The array then processes the speech and sends out the process signal to the DSLA. The DSLA then does a comparison of what it sent and what it receives," Pleva says.

The primary performance concern is speech intelligibility. Although quality of sound is also important, the main interest is that as many words as possible be successfully transmitted both ways. This can be effectively measured using the equipment in place.

"The next step would be to build an even higher fidelity version of this integrated audio system. Then we'll do another round of these tests. Eventually, we'll have a human being tested inside a pressure chamber," says Dave Irimies, a computer engineer and ETDP lead at Glenn.

Advancing Technology

The ongoing research, development and testing of this integrated audio system is part of the Space Audio Development and Evaluation Laboratory at Glenn.

"Our direction is replacing the current suit on the space station and shuttle. The current certification runs out in ten years, in 2020, so… this is an opportunity to use even more advanced technology," Irimies says. "This work is pressing forward."

The team hopes that the integrated audio system can commence testing on the space station in 2016. The technology may also be useful for communicating inside the station as well as during space walks. There may also be the potential that the technology can help on Earth. WeVoice Inc. is currently working with the University of Pittsburg on one potential spin-off: developing a teleconferencing system using microphone arrays for operating rooms in hospitals.

The team looks forward to working together to continue testing and evolving their integrated audio system, with the goal of significantly influencing how the next generation space suit will work.

"We all challenge each other in different ways, all the time," Sands says. "It's a lot of fun, getting new concepts infused into space systems. That's what NASA is all about."

Tori Woods, SGT Inc.
NASA’s Glenn Research Center

Source NASA