NASA Helps Create a More Silent Night-NASA's information

The holidays are here and the nation's airports are busier than ever –thousands of airplanes taking off and landing. Passengers and people living around airports are reminded that the airplane is not the quietest mode of transportation; certainly not as quiet as a sleigh pulled by eight tiny reindeer. Fear not, because even while travelers are heading home, NASA continues working with others in industry and academia on technologies that will create a more silent night (and day) around airports.

One of the most recent noise-reducing technologies shepherded through the research process by NASA and now making a difference on commercial jet engines is chevrons. Chevrons are the sawtooth pattern seen on the trailing edges of some jet engine nozzles. As hot air from the engine core mixes with cooler air blowing through the engine fan, the shaped edges serve to smooth the mixing, which reduces turbulence that creates noise.

Exploding Stars and Stripes-NASA's Information

The discovery of a pattern of X-ray “stripes” in the remains of an exploded star may provide the first direct evidence that a cosmic event can accelerate particles to energies a hundred times higher than achieved by the most powerful particle accelerator on Earth.This result comes from a very long observation of the Tycho supernova remnant with NASA's Chandra X-ray Observatory. It could explain how some of the extremely energetic particles bombarding the Earth, called cosmic rays, are produced. “We've seen lots of intriguing structures in supernova remnants, but we’ve never seen stripes before,” said Kristoffer Eriksen of Rutgers University, who led the study. “This made us think very hard about what's happening in the blast wave of this powerful explosion.” This latest study from Chandra provides support for a theory about how magnetic fields can be dramatically amplified in such blast waves.

In this theory, the magnetic fields become highly tangled and the motions of the particles very turbulent near the expanding supernova shock wave at the front edge of the supernova remnant. High-energy charged particles can bounce back and forth across the shock wave repeatedly, gaining energy with each crossing. Theoretical models of the motion of the most energetic particles -- which are mostly protons -- are predicted to leave a messy network of holes and dense walls corresponding to weak and strong regions of magnetic fields, respectively. The X-ray stripes discovered by the Chandra researchers are thought to be regions where the turbulence is greater and the magnetic fields more tangled than surrounding areas, and may be the walls predicted by the theory. Electrons become trapped in these regions and emit X-rays as they spiral around the magnetic field lines.

However, the regular and almost periodic pattern of the X-ray stripes was not predicted by the theory. "It was a big surprise to find such a neatly arranged set of stripes," said co-author Jack Hughes, also of Rutgers. "We were not expecting so much order to appear in so much chaos. It could mean that the theory is incomplete, or that there's something else we don't understand."

Commercial Rocket Engine Testing at NASA center

NASA's Stennis Space Center is moving ahead in supporting Orbital Sciences Corporation testing of Aerojet's AJ26 engines for commercial cargo flights to the International Space Station.

Orbital plans to launch the first of eight scheduled unmanned cargo missions to the ISS in early 2012. Key steps already have been taken toward that goal as Orbital has successfully tested the Aerojet AJ26 engines that will power the first stage of their Taurus II rocket. Tests on each of the engines were performed by a team of Orbital, Aerojet and John C. Stennis Space Center engineers at NASA’s south Mississippi test facility. The latest test was conducted on March 19 on the E-1 Test Stand.

The initial two engines, tested earlier this year, will be delivered to Orbital at the Wallops Flight Facility launch site in Virginia for integration with the Taurus II’s first stage core.

NASA-Space Shuttle Program

The National Aeronautics and Space Administration (NASA) is an Executive Branch agency of the United States government, responsible for the nation's civilian space program and aeronautics and aerospace research. Since February 2006, NASA's self-described mission statement is to "pioneer the future in space exploration, scientific discovery and aeronautics research".
NASA was established by the National Aeronautics and Space Act on July 29, 1958, replacing its
predecessor, the National Advisory Committee for Aeronautics (NACA). The agency became operational on October 1, 1958. NASA has led U.S. efforts for space exploration since, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and has been developing the manned Orion spacecraft.

Space Shuttle Program

NASA's Space Shuttle program, officially called Space Transportation System (STS), is the United States government's current manned launch vehicle. The winged Space Shuttle orbiter is launched vertically, usually carrying five to seven astronauts (although eight have been carried) and up to 50,000 lb (22 700 kg) of payload into low earth orbit. When its mission is complete, the shuttle can independently move itself out of orbit using its Maneuvering System (it orients itself appropriately and fires its main OMS engines, thus slowing it down) and re-enter the Earth's atmosphere. During descent and landing the orbiter acts as a re-entry vehicle and a glider, using its OMS system and flight surfaces to make adjustments.
The shuttle is the only winged manned spacecraft to achieve orbit and land, and the only reusable space vehicle that has ever made multiple flights into orbit. Its missions involve carrying large payloads to various orbits (including segments to be added to the International Space Station), providing crew rotation for the International Space Station, and performing service missions. The orbiter has also recovered satellites and other payloads from orbit and return them to Earth, but its use in this capacity was rare. However, the shuttle has previously been used to return large payloads from the ISS to Earth, as the Russian Soyuz spacecraft has limited capacity for return payloads. Each vehicle was designed with a projected lifespan of 100 launches, or 10 years' operational life.

NASA Lunar Reconnaissance Orbiter Delivers Treasure Trove of Data

NASA's Lunar Reconnaissance Orbiter (LRO) team released Tuesday the final set of data from the mission's exploration phase along with the first measurements from its new life as a science satellite.

With this fifth release of data, striking new images and maps have been added to the already comprehensive collection of raw lunar data and high-level products, including mosaic images, that LRO has made possible. The spacecraft's seven instruments delivered more than 192 terabytes of data with an unprecedented level of detail. It would take approximately 41,000 typical DVDs to hold the new LRO data set.

"The release of such a comprehensive and rich collection of data, maps and images reinforces the tremendous success we have had with LRO in the Exploration Systems Mission Directorate and with lunar science," said Michael Wargo, chief lunar scientist of the Exploration Systems Mission Directorate at NASA Headquarters in Washington.

MESSENGER Poised for Mercury Orbit Insertion

After more than a dozen laps through the inner solar system, NASA's MESSENGER spacecraft will move into orbit around Mercury on March 17, 2011. The durable spacecraft carrying seven science instruments and fortified against the blistering environs near the sun will be the first to orbit the innermost planet.

At 8:45 p.m. EDT, MESSENGER having pointed its largest thruster very close to the direction of travel will fire that thruster for nearly 14 minutes, with other thrusters firing for an additional minute, slowing the spacecraft by 862 meters per second (1,929 mph) and consuming 31 percent of the propellant that the spacecraft carried at launch. Less than 9.5 percent of the usable propellant at the start of the mission will remain after completing the orbit insertion maneuver, but the spacecraft will still have plenty of propellant for future orbit correction maneuvers.

The orbit insertion will place the spacecraft into a 12-hour orbit about Mercury with a 200 kilometer (124 mile) minimum altitude. At the time of orbit insertion, MESSENGER will be 46.14 million kilometers (28.67 million miles) from the sun and 155.06 million kilometers (96.35 million miles) from Earth.

Japan earthquake: Tsunami hits north-east

Japan's most powerful earthquake since records began has struck the north-east coast, triggering a massive tsunami.

Cars, ships and buildings were swept away by a wall of water after the 8.9-magnitude tremor, which struck about 400km (250 miles) north-east of Tokyo.

A state of emergency has been declared at a nuclear power plant, where pressure has exceeded normal levels.

Officials say 350 people are dead and about 500 missing, but it is feared the final death toll will be much higher.

In one ward alone in Sendai, a port city in Miyagi prefecture, 200 to 300 bodies were found.
In the centre of Tokyo many people are spending the night in their offices. But thousands, perhaps millions, chose to walk home. Train services were suspended.

Even after the most violent earthquake anyone could remember the crowds were orderly and calm. The devastation is further to the north, along the Pacific coast.

There a tsunami triggered by the quake reached 10km (six miles) inland in places carrying houses, buildings, boats and cars with it. In the city of Sendai the police found up to 300 bodies in a single ward. Outside the city in a built-up area a fire blazed across several kilometres.

Japan's ground self-defence forces have been deployed, and the government has asked the US military based in the country for help. The scale of destruction from the biggest quake ever recorded in Japan will become clear only at first light.

The quake was the fifth-largest in the world since 1900 and nearly 8,000 times stronger than the one which devastated Christchurch, New Zealand, last month, said scientists.

Thousands of people living near the Fukushima nuclear power plant have been ordered to evacuate.

Japanese nuclear officials said pressure inside a boiling water reactor at the plant was running much higher than normal after the cooling system failed.

Officials said they might need to deliberately release some radioactive steam to relieve pressure, but that there would be no health risk.

US Secretary of State Hillary Clinton had earlier said the US Air Force had flown emergency coolant to the site.

But US officials later said no coolant had been handed over because the Japanese had decided to handle the situation themselves.

The UN's nuclear agency said four nuclear power plants had shut down safely.

Measured at 8.9 by the US Geological Survey, it struck at 1446 local time (0546 GMT) at a depth of about 24km.

The tsunami rolled across the Pacific at 800km/h (500mph) - as fast as a jetliner - before hitting Hawaii and the US West Coast, but there were no reports of major damage from those regions.

Thousands of people were ordered to evacuate coastal areas in the states of California, Oregon and Washington.

The biggest waves of more than 6-7ft (about 2m) were recorded near California's Crescent City, said the Pacific Tsunami Warning Centre.

A tsunami warning extended across the Pacific to North and South America, where many other coastal regions were evacuated, but the alert was later lifted in most parts, including the Philippines, Australia and China.

Strong waves hit Japan's Miyagi and Fukushima prefectures, damaging dozens of coastal communities.

A 10m wave struck Sendai, deluging farmland and sweeping cars across the airport's runway. Fires broke out in the centre of the city.

* Four trains are missing along the coast, says Japan Railways; and a ship carrying 100 people was swept away
* Fire has engulfed swathes of the coast in Miyagi prefecture's Kesennuma city, one-third of which is reportedly under water
* A major explosion hit a petrochemical plant in Sendai; further south a huge blaze swept an oil refinery in Ichihara city, Chiba prefecture
* Some 1,800 homes are reported to have been destroyed in the city of Minamisoma, Fukushima prefecture
* A dam burst in north-eastern Fukushima prefecture, sweeping away homes, Kyodo news agency reports
* At least 20 people were injured in Tokyo when the roof of a hall collapsed on to a graduation ceremony

In a televised address, Prime Minister Naoto Kan extended his sympathy to the victims of the disaster.


As aftershocks rattled the country, residents and workers in Tokyo rushed outside to gather in parks and open spaces.

Many people in the Japanese capital said they had never felt such a powerful earthquake.

In central Tokyo, a number of office workers are spending the night in their offices because the lifts have stopped working.

"This is the kind of earthquake that hits once every 100 years," said restaurant worker Akira Tanaka.

Train services were suspended, stranding millions of commuters in the Japanese capital.
About four million homes in and around Tokyo suffered power cuts

NASA Study Goes to Earth's Core for Climate Insights

The latest evidence of the dominant role humans play in changing Earth's climate comes not from observations of Earth's ocean, atmosphere or land surface, but from deep within its molten core.

Scientists have long known that the length of an Earth day - the time it takes for Earth to make one full rotation - fluctuates around a 24-hour average. Over the course of a year, the length of a day varies by about 1 millisecond, getting longer in the winter and shorter in the summer. These seasonal changes in Earth's length of day are driven by exchanges of energy between the solid Earth and fluid motions of Earth's atmosphere (blowing winds and changes in atmospheric pressure) and its ocean. Scientists can measure these small changes in Earth's rotation using astronomical observations and very precise geodetic techniques.


But the length of an Earth day also fluctuates over much longer timescales, such as interannual (two to 10 years), decadal (approximately 10 years), or those lasting multiple decades or even longer. A dominant longer timescale mode that ranges from 65 to 80 years was observed to change the length of day by approximately 4 milliseconds at the beginning of the 20th century.

These longer fluctuations are too large to be explained by the motions of Earth's atmosphere and ocean. Instead, they're due to the flow of liquid iron within Earth's outer core, where Earth's magnetic field originates. This fluid interacts with Earth's mantle to affect Earth's rotation. While scientists cannot observe these flows directly, they can deduce their movements by observing Earth's magnetic field at the surface. Previous studies have shown that this flow of liquid iron in Earth's outer core oscillates, in waves of motion that last for decades with timescales that correspond closely to long-duration variations in Earth's length of day.

Still other studies have observed a link between the long-duration variations in Earth's length of day and fluctuations of up to 0.2 degrees Celsius (0.4 degree Fahrenheit) in Earth's long-term global average surface air temperature.

So how might all three of these variables - Earth's rotation, movements in Earth's core (formally known as the core angular momentum) and global surface air temperature - be related? That's what researchers Jean Dickey and Steven Marcus of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and colleague Olivier de Viron of the Universite Paris Diderot and Institut de Physique du Globe de Paris in France, set out to discover in a first-of-its-kind study.

The scientists mapped existing data from a model of fluid movements within Earth's core and data on yearly averaged length-of-day observations against two time series of observed annual global average surface temperature: one from NASA's Goddard Institute of Space Studies in New York that extends back to 1880, and another from the United Kingdom's Met Office that extends back to 1860. Since total air temperature is composed of two components - temperature changes that occur naturally and those caused by human activities - the researchers used results from computer climate models of Earth's atmosphere and ocean to account for temperature changes due to human activities. These human-produced temperature changes were then subtracted from the total observed temperature records to generate corrected temperature records.

The researchers found that the uncorrected temperature data correlated strongly with data on movements of Earth's core and Earth's length of day until about 1930. They then began to diverge substantially: that is, global surface air temperatures continued to increase, but without corresponding changes in Earth's length of day or movements of Earth's core. This divergence corresponds with a well-documented, robust global warming trend that has been widely attributed to increased levels of human-produced greenhouse gases.

But an examination of the corrected temperature record yielded a different result: the corrected temperature record remained strongly correlated with both Earth's length of day and movements of Earth's core throughout the entire temperature data series. The researchers performed robust tests to confirm the statistical significance of their results.

"Our research demonstrates that, for the past 160 years, decadal and longer-period changes in atmospheric temperature correspond to changes in Earth's length of day if we remove the very significant effect of atmospheric warming attributed to the buildup of greenhouse gases due to mankind's enterprise," said Dickey. "Our study implies that human influences on climate during the past 80 years mask the natural balance that exists among Earth's rotation, the core angular momentum and the temperature at Earth's surface."

So what mechanism is driving these correlations? Dickey said scientists aren't sure yet, but she offered some hypotheses.

Since scientists know air temperature can't affect movements of Earth's core or Earth's length of day to the extent observed, one possibility is the movements of Earth's core might disturb Earth's magnetic shielding of charged-particle (i.e., cosmic ray) fluxes that have been hypothesized to affect the formation of clouds. This could affect how much of the sun's energy is reflected back to space and how much is absorbed by our planet. Other possibilities are that some other core process could be having a more indirect effect on climate, or that an external (e.g. solar) process affects the core and climate simultaneously.

Regardless of the eventual connections to be established between the solid Earth and climate, Dickey said the solid Earth's impacts on climate are still dwarfed by the much larger effects of human-produced greenhouse gases. "The solid Earth plays a role, but the ultimate solution to addressing climate change remains in our hands," she concluded.

Study results were published recently in the Journal of Climate.

For more information, see: http://www.jpl.nasa.gov/news/features.cfm?feature=2420 and
http://www.jpl.nasa.gov/news/features.cfm?feature=15 .