Blogarchiv

Sonntag, 3. Mai 2015 - 22:30 Uhr

Luftfahrt - Erstes Flugauto von Carplane vor Zulassung in Deutschland

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Flugautos werden bald Realität. Und Carplane® ist weltweit das einzige Flugauto im Zulassungsverfahren. Verfolgen Sie auf dieser Website, wie wir das Verfahren abschließen.

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Der Carplane® wurde vom 15. bis 18. April 2015 auf der AERO in Friedrichshafen erstmals öffentlich vorgestellt

Carplane® Luft/Boden Vehikel
Der Carplane® ist ein bimodales Fahrzeug für den Individualverkehr. Er wird weltweit das erste herkömmlich zugelassene Flugzeug, das die strenge Abgasnorm für den Straßengebrauch erfüllt. Der Motor befindet sich zwischen zwei Rümpfen, wo Lärmemissionen verringert sind. Die Modus-Verwandlung dauert 15 Sekunden. Er wird zur Zeit am Forschungsflughafen in Braunschweig entwickelt.
Quelle: Carplane

Tags: Luftfahrt 

1912 Views

Sonntag, 3. Mai 2015 - 19:30 Uhr

Raumfahrt - Erfolgreicher ISRO-Test von Cryogenic Raketenantrieb

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A major milestone in the development of ISRO’s next generation launch vehicle, GSLV MkIII, was achieved on successful long duration hot test (635 seconds) of high thrust cryogenic engine (CE20) on 28-04-2015 at ISRO Propulsion Complex, Mahendragiri, Tamil Nadu. The CE20 cryogenic engine is being indigenously developed by ISRO to power the cryogenic stage of GSLV MkIII launch vehicle.

The completion of successful long duration hot test has once again proved ISRO’s capability in mastering the complex cryogenic technology. All subsystems of this engine such as Thrust Chamber, Injector, Gas Generator, LOX & LH2 Turbopumps, Control Components, Pyro systems etc., and the ground Test Facility systems performed very well and the parameters are well within the prediction.
A series of development tests on this engine are being carried out to validate the performance and to prove the design of the engine. Two cold start tests and four short duration hot tests were already carried out on this engine at IPRC, Mahendragiri.
Quelle: ISRO
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ISRO Carries Out Series of Cryogenic Engine Development Tests

IRNSS-1C spacecraft undergoing Electro- Magnetic Interference and Electro-magnetic compatibility. (Courtesy isro.org)
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BRNGALURU: After successful test of the high thrust cryogenic engine recently, a series of development tests on the engine are being carried out to validate the performance and to prove its design, Indian Space Research Organisation (ISRO) has said.
Successful long duration hot test (635 seconds) of high thrust cryogenic engine (CE20) was carried out on April 28 at ISRO Propulsion Complex in Tamil Nadu's Mahendragiri. The achievement is considered as a major milestone in the development of next generation launch vehicle, GSLV MkIII, ISRO said.
The CE20 cryogenic engine is being indigenously developed by ISRO to power the cryogenic stage of GSLV MkIII launch vehicle, ISRO has posted on its Facebook page.
The completion of successful long duration hot test has once again proved ISRO's capability in mastering the complex cryogenic technology, it said.
Sharing details about the test, ISRO said all subsystems of this engine such as Thrust Chamber, Injector, Gas Generator, LOX & LH2 Turbopumps, Control Components, Pyro systems etc, and the ground Test Facility systems performed very well and the parameters are well within the prediction.
It said a series of development tests on this engine are being carried out to validate the performance and to prove the design of the engine, adding, two cold start tests and four short duration hot tests were already carried out on this engine at ISRO Propulsion Complex (IPRC), Mahendragiri.
The indigenously developed cryogenic engine will help India put satellites of upto four tonnes in geostationary orbit.
Quelle: The INDIAN EXPRESS

Tags: Raumfahrt 

1829 Views

Sonntag, 3. Mai 2015 - 12:30 Uhr

UFO-Forschung - Aus dem CENAP-Archiv: Die besten UFO Fakes des DOCMA Awards 2004

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Aus dem CENAP-Archiv:

Quelle: DOCMA , CENAP-Archiv


Tags: UFO-Forschung 

1805 Views

Sonntag, 3. Mai 2015 - 11:49 Uhr

Astronomie - Im Focus von Chandra: Supermassive schwarze Löcher

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NASA's Chandra Suggests Black Holes Gorging at Excessive Rates
A group of unusual giant black holes may be consuming excessive amounts of matter, according to a new study using NASA’s Chandra X-ray Observatory. This finding may help astronomers understand how the largest black holes were able to grow so rapidly in the early Universe.
Astronomers have known for some time that supermassive black holes − with masses ranging from millions to billions of times the mass of the Sun and residing at the centers of galaxies − can gobble up huge quantities of gas and dust that have fallen into their gravitational pull. As the matter falls towards these black holes, it glows with such brilliance that they can be seen billions of light years away. Astronomers call these extremely ravenous black holes “quasars.”
This new result suggests that some quasars are even more adept at devouring material than scientists previously knew.
“Even for famously prodigious consumers of material, these huge black holes appear to be dining at enormous rates, at least five to ten times faster than typical quasars,” said Bin Luo of Penn State University in State College, Pennsylvania, who led the study.
Luo and his colleagues examined data from Chandra for 51 quasars that are located at a distance between about 5 billion and 11.5 billion light years from Earth. These quasars were selected because they had unusually weak emission from certain atoms, especially carbon, at ultraviolet wavelengths. About 65% of the quasars in this new study were found to be much fainter in X-rays, by about 40 times on average, than typical quasars.
The weak ultraviolet atomic emission and X-ray fluxes from these objects could be an important clue to the question of how a supermassive black hole pulls in matter. Computer simulations show that, at low inflow rates, matter swirls toward the black hole in a thin disk. However, if the rate of inflow is high, the disk can puff up dramatically, because of pressure from the high radiation, into a torus or donut that surrounds the inner part of the disk.
“This picture fits with our data,” said co-author Jianfeng Wu of the Harvard-Smithsonian Center for Astrophysics, in Cambridge, Massachusetts. "If a quasar is embedded in a thick donut-shaped structure of gas and dust, the donut will absorb much of the radiation produced closer to the black hole and prevent it from striking gas located further out, resulting in weaker ultraviolet atomic emission and X-ray emission."
The usual balance between the inward pull of gravity and the outward pressure of radiation would also be affected.
"More radiation would be emitted in a direction perpendicular to the thick disk, rather than along the disk, allowing material to fall in at higher rates," said co-author Niel Brandt, also of Penn State University.
The important implication is that these “thick-disk” quasars may harbor black holes growing at an extraordinarily rapid rate. The current study and previous ones by different teams suggest that such quasars might have been more common in the early Universe, only about a billion years after the Big Bang. Such rapid growth might also explain the existence of huge black holes at even earlier times.
A paper describing these results appears in an upcoming issue of The Astrophysical Journal and is available online. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for the agency’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
Quelle: NASA

Tags: Astronomie 

1804 Views

Sonntag, 3. Mai 2015 - 11:11 Uhr

Planet Erde - NASA Aufzeichnungen zeigen Folgen von Nepal Erdbeben

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SPoRT Satellite Image as Detected by the Visible Infrared Imaging Radiometer Suite Sensor of the Post Kathmandu Earthquake.

In the wake of the April 25, 2015 earthquake in Nepal, NASA’s Short-term Prediction Research and Transition, SPoRT, project at Marshall Space Flight Center has developed satellite imagery to assist decision makers in post disaster analysis and assessment.
The experimental image shows a decrease in emitted light over the city of Kathmandu and surrounding areas as detected by the Visible Infrared Imaging Radiometer Suite (VIIRS) “Day-Night Band” sensor aboard the NASA/NOAA Suomi National Polar-Orbiting Partnership satellite, derived from a comparison of pre-earthquake (22 April 2015) and post-earthquake (26 April 2015) imagery.  In this percent of normal product, the warm colors (red – yellow) indicate the largest reduced light emissions in the post-event image, possibly due to damage to electrical infrastructure.  Clouds in the scene are shaded in purple, which will contaminate the comparison. Towns and suburban areas around Kathmandu show the larger percentage of reduced light emission.  Input satellite data were obtained in collaboration with the NASA Suomi NPP Science Investigator-led Processing System activities at the University of Wisconsin.
This information can help relief operations determine areas that may be affected by electrical outages.
Images Produced By: The Short-term Prediction Research and Transition (SPoRT) team at NASA’s Marshall Space Flight Center in Huntsville, AL.
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GPS Data Show How Nepal Quake Disturbed Earth’s Upper Atmosphere
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The April 25, 2015, magnitude 7.8 Gorkha earthquake in Nepal created waves of energy that penetrated into Earth's upper atmosphere in the vicinity of Nepal, disturbing the distribution of electrons in the ionosphere. The ionosphere is a region of Earth's upper atmosphere located from about 37 miles (60 kilometers) to 621 miles (1,000 kilometers) above Earth’s surface. These disturbances were monitored using signals transmitted by the Global Positioning System (GPS) that were received by a science-quality GPS receiver located in a neighboring region to Nepal.
The disturbance measurements, known as vertical total electron content (VTEC) (depicted in blue in the upper panel), have been filtered using processing software developed by NASA’s Jet Propulsion Laboratory, Pasadena, California, to show wave-like disturbances (circled in red) in the distribution of electrons in the ionosphere. The waves have periods of between two and eight minutes in length. The disturbance measurements following the earthquake rupture are circled in black in the lower panel. The colors represent the relative strengths of the earthquake-induced ionospheric disturbances as captured by the GPS signals, with red being high and blue being low.
The data show that after the initial earthquake rupture (indicated by the vertical black line) it took about 21 minutes for the earthquake-generated ionospheric disturbance to reach a GPS station (LHAZ), located about 400 miles (640 kilometers) away from the epicenter in Lhasa, Tibet, China. The station is hosted at the Tibet Autonomous Regional Bureau of Surveying and Mapping Institute. The site collects both GPS and GLONASS (the Russian global navigation satellite system) data at a rate of 1 Hertz and is part of an international scientific collaboration known as the International GPS Service (IGS) 
Scientists study ionosphere-based measurements caused by natural hazards such as earthquakes, volcanic eruptions and tsunamis to better understand wave propagation in the upper atmosphere. The disturbances caused by earthquakes help scientists develop new first-principle-based wave propagation models. These models may become part of future early warning systems for tsunamis and other difficult-to-detect natural hazards.
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NASA-Generated Damage Map to Assist with 2015 Gorkha, Nepal Earthquake Disaster Response
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NASA data and expertise are providing valuable information for the ongoing response to the April 25, 2015, magnitude 7.8 Gorkha earthquake in Nepal. The quake has caused significant regional damage and a humanitarian crisis. It was the strongest earthquake to occur in that vicinity since a magnitude 8.0 quake there in 1934 that caused more than 10,000 fatalities.
To assist in the disaster response efforts, scientists at NASA's Jet Propulsion Laboratory, Pasadena, California, and California Institute of Technology in Pasadena, in collaboration with the Italian Space Agency (ASI), generated these images of the earthquake’s hardest-hit region. 
The 25-by-31 mile (40-by-50 kilometer) Damage Proxy Map (DPM), which covers the region around Kathmandu, was processed by the Advanced Rapid Imaging and Analysis (ARIA) team at JPL and Caltech using X-band interferometric synthetic aperture radar data from ASI’s COSMO-SkyMed satellite constellation. The technique uses a prototype algorithm to rapidly detect surface changes caused by natural or human-produced damage. The assessment technique is most sensitive to destruction of the built environment. When the radar images areas with little to no destruction, its image pixels are transparent. Increased opacity of the radar image pixels reflects damage, with areas in red reflecting the heaviest damage to cities and towns. The color variations from yellow to red indicate increasingly more significant ground surface change. The time span of the data for the change is Nov. 24, 2014 to April 29, 2015. Each pixel in the damage proxy map is about 100 feet (30 meters) across. 
The perspective image below the main image shows the DPM overlaid on the terrain with the locations of damaged buildings identified by the National Geospatial-Intelligence Agency (NGA) preliminary damage assessment, indicated by the red and purple dots.  As an example, the images on the side show how red regions in the DPM correlate with damaged buildings, as shown by the collapsed structures in the "after" image. The base map images were provided by Google. Before and after images were provided by DigitalGlobe.
Preliminary validation was done by comparing to damage assessment from imagery by NGA (April 30, 2015 preliminary damage assessment product) and the United Nations (UNITAR/UNOSAT) in collaboration with the U.S. Geological Survey (USGS) and the University of Basilicata.
ARIA is a JPL- and NASA-funded project being developed by JPL and Caltech. It is building an automated system for providing rapid and reliable GPS and satellite data to support the local, national and international hazard monitoring and response communities. Using space-based imagery of disasters, ARIA data products can provide rapid assessments of the geographic region impacted by a disaster, as well as detailed imaging of the locations where damage occurred. COSMO-SkyMed data was made freely available for the disaster response by ASI.
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NASA's ARIA Project Maps Deformation of Earth's Surface from Nepal Quake
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NASA and its partners are contributing important observations and expertise to the ongoing response to the April 25, 2015, magnitude 7.8 Gorkha earthquake in Nepal. The quake was the strongest to occur in that area since the 1934 Nepal-Bihar magnitude 8.0 event and caused significant regional damage and a humanitarian crisis.
Scientists with the Advanced Rapid Imaging and Analysis project (ARIA), a collaboration between NASA's Jet Propulsion Laboratory, Pasadena, California, and the California Institute of Technology in Pasadena, analyzed interferometric synthetic aperture radar images from the European Union's Copernicus Sentinel-1A satellite, operated by the European Space Agency and also available from the Alaska Satellite Facility (https://www.asf.alaska.edu), to calculate a map of the deformation of Earth's surface caused by the quake. This false-color map shows the amount of permanent surface movement caused almost entirely by the earthquake, as viewed by the satellite, during a 12-day interval between two Sentinel-1 images acquired on April 17 and April 29, 2015.
In the map, surface displacements are seen as color contours (or "fringes"), where each color cycle represents 8 inches (20 centimeters) of surface motion. The contours show the land around Kathmandu has moved upward by more than 40 inches (1 meter). Areas without the color contours have snow or heavy vegetation that affects the radar measurements. Scientists use these maps to build detailed models of the fault and associated land movements to better understand the impact on future earthquake activity. The background image is from Google Earth. The map contains Copernicus data (2015).
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Landsat 8 Reveals Extent of Quake Disaster in Nepal’s Langtang Valley
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The magnitude 7.8 Gorkha earthquake that struck Nepal on April 25, 2015, caused extensive damage in Kathmandu Valley and severely affected Nepal's rural areas. The Langtang Valley in the Rasuwa district was particularly hard hit, as became apparent from pictures taken by a rescue helicopter mission on April 26. Numerous tourists and Nepali were, or are, still trapped in the valley as access is completely blocked by avalanches and landslides. The valley’s main village, Langtang , was completely destroyed by the earthquake and the large, wet, debris- and ice-rich avalanche and likely pressure wave from dust avalanche that it triggered, resulting in an unknown number of casualties.  Other avalanches also struck elsewhere in the valley.
Space agencies around the world are providing extensive resources in a huge international effort. They are tasking their satellites to observe the areas hit by the earthquake. This effort began immediately after the disaster. Imaging initially focused on Kathmandu. Following the first social media reporting of the helicopter pilot’s comments, an emergency NASA-USGS-interagency Earthquake Response Team alerted satellite mission operations teams about the likely serious plight of Langtang and other Himalayan valleys.  Advisories were also delivered to Nepal officials.  The first relief missions arrived in the Langtang Valley about April 28.
United States Geological Survey/NASA Landsat-8 satellite observations were first obtained over Nepal after the earthquake on April 30. Landsat 8 acquired the first largely cloud-free image of the Langtang Valley (post-event Landsat image ID: LS081410412015043000000000MS00_GO006005004). Scientists analyzed the imagery and compared it with pre-earthquake imagery from a year earlier.
The analyses revealed the true extent of the disaster that took place in the Langtang Valley. Part of Langtang village was completely buried by a very large rock and ice avalanche that originated on the northwestern slopes above the village. The eastern part of Langtang village appears to have been destroyed by the pressure wave from the related dust avalanche. Large landslides or avalanches also affected the villages of Thyangshyup, Tsarding, Chyamki, Gumba, Mundu, Sindum and Kyangjing. The extent of the damage around these small settlements will require further investigation using higher-resolution imagery to be obtained from satellites, and word from relief crews on the ground. The river at the Langtang village avalanche appears to be blocked, but there is no evidence yet of a lake forming behind the blockage. This may indicate that the water has found its way through the debris, snow and ice. The valley is vulnerable to secondary events such as mudslides and debris and ice avalanches, and this situation could continue into the coming monsoon.  Researchers will continue to monitor this situation closely using satellite data.
These scientists are part of a 35-member international volunteer group led by University of Arizona scientists Jeffrey Kargel and Gregory Leonard, who launched the group soon after the earthquake occurred. This effort has been incorporated into the NASA-USGS-interagency Earthquake Response Team. Their goal is to systematically investigate the entire quake-affected area using remote sensing. Their results will support relief operations and identify secondary hazards, such as glacier lake outbursts, rivers blocked by landslides and other unstable areas.  This is the first volunteer report of the project.
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Nepal's Imja Lake, Khumbu Region, Appears Resilient Against Gorkha Quake
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Nepal's Imja Lake is a typical large glacial lake created by a moraine dam (formed by accumulations of dirt and rocks -- commonly cemented by ice -- that have been transported and deposited by a glacier). Located near Mount Everest, the local topographic relief is extremely high. Imja Lake was recently the site of an intensive scientific survey supported by the United Nations' Development Program to re-assess the outburst flood potential of the lake and to design and, this spring, implement a project to lower the lake level and reduce the flood hazard. The project had not been completed when the earthquake struck. The lake is also the site of a planned micro-hydroelectric power plant.
The lake began forming as a series of ponds on the glacier surface around 1960. By the mid 1970’s, the ponds had combined into a single large lake, which has continued to grow since then as the glaciers feeding it have retreated and thinned. The lake’s growth effectively cut off what had been the debris-covered terminus of the glacier, which now stands as an ice-cored end moraine. The moraine’s unconsolidated rock debris and the ice have been unstable, both gravitationally and thermally, for many years.  The high lateral moraines, the high bedrock ridges that almost surround the lake, and the hanging glaciers perched above it could be de-stabilized, such as from ground shaking, and trigger an outburst flood. Fortunately, the present lake level is only about 100 feet (30 meters) higher than the area immediately downstream from the end moraine, thereby limiting the volume of water that could be released. The wideness of the end moraine previously had reduced the chances of a sudden outburst, but the growth in the past few years of ponds on the end moraine has weakened the dam, making it less able to contain the lake.
A bathymetric (lake depth) map from the recent survey is shown above, superposed on an EO-1 ALI image dating from before the earthquake. The survey found the lake to be up to 492 feet (149.8 meters) deep and to contain about 75 million cubic meters of water, of which about one-third is readily drainable in the event of a glacier lake outburst flood.  The aforementioned lake lowering will reduce the level by only 10 feet (3 meters), which will reduce the outburst flood problem but not eliminate it.
The lake remains very hazardous, so it is with much relief that Imja Lake survived the 2015 Gorkha quake without huge effects visible in the first acquired post-quake satellite image from NASA’s EO-1 satellite (black and white image below). However, further satellite image analysis and boots and eyes on the ground are needed to confirm this. 
This work is supported by NASA’s SERVIR Applied Science Team and is in support of the emergency NASA-USGS-Interagency Earthquake Response Team.
Quelle: NASA

Tags: Planet Erde 

1906 Views

Samstag, 2. Mai 2015 - 20:14 Uhr

Luftfahrt-History - 1957: Rene Leduc fliegendes Ofenrohr

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Aus dem CENAP-Archiv: 

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Quelle: Hobby 7-1957 / CENAP-Archiv

 


Tags: Luftfahrt 

1550 Views

Samstag, 2. Mai 2015 - 19:25 Uhr

Astronomie - Pulsar mit Widest Orbit von Studenten entdeckt

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Pulsar with Widest Orbit Ever Detected, Discovered By High School Research Team
A team of highly determined high school students discovered a never-before-seen pulsar by painstakingly analyzing data from the National Science Foundation’s (NSF) Robert C. Byrd Green Bank Telescope (GBT). Further observations by astronomers using the GBT revealed that this pulsar has the widest orbit of any around a neutron star and is part of only a handful of double neutron star systems.
This impressive find will help astronomers better understand how binary neutron star systems form and evolve. 
Pulsars are rapidly spinning neutron stars, the superdense remains of massive stars that have exploded as supernovas. As a pulsar spins, lighthouse-like beams of radio waves, streaming from the poles of its powerful magnetic field, sweep through space. When one of these beams sweeps across the Earth, radio telescopes can capture the pulse of radio waves.
“Pulsars are some of the most extreme objects in the universe,” said Joe Swiggum, a graduate student in physics and astronomy at West Virginia University in Morgantown and lead author on a paper accepted for publication in the Astrophysical Journal explaining this result and its implications. “The students’ discovery shows one of these objects in a really unique set of circumstances.”
About 10 percent of known pulsars are in binary systems; the vast majority of these are found orbiting ancient white dwarf companion stars. Only a rare few orbit other neutron stars or main sequence stars like our Sun. The reason for this paucity of double neutron star systems, astronomers believe, is the process by which pulsars and all neutron stars form. 
When a massive star goes supernova at the end of its normal life, the explosion can be a little one-sided, imparting a “kick” to the remaining stellar core. When this happens, the resulting neutron star is sent hurtling through space. These kicks -- and the corresponding mass loss from a supernova explosion -- mean that the chances of two such stars remaining gravitationally locked in the same system are remarkably slim. 
This pulsar, which received the official designation PSR J1930-1852, was discovered in 2012 by Cecilia McGough, who was a student at Strasburg High School in Virginia at the time, and De’Shang Ray, who was a student at Paul Laurence Dunbar High School in Baltimore, Maryland. 
These students were participating in a summer Pulsar Search Collaboratory (PSC) workshop, which is an NSF-funded educational outreach program that involves interested high school students in analyzing pulsar survey data collected by the GBT. Students often spend weeks and months poring over data plots, searching for the unique signature that identifies a pulsar. Those who identify strong pulsar candidates are invited to Green Bank to work with astronomers to confirm their discovery. 
Astronomers determined that this new pulsar is part of a binary system, based on the differences in its spin frequency (revolutions per second) between the original detection and follow-up observations. 
Optical telescope surveys of the same area of the sky, however, revealed no visible companion – which would have been clearly seen if it were a white dwarf star or main sequence star. “Given the lack of any visible signals and the careful review of the timing of the pulsar, we concluded that the most likely companion was another neutron star,” said Swiggum. 
Further analysis of the timing of the pulses indicates that the two neutron stars have the widest separation ever observed in a double neutron star system. 
Some pulsars in double neutron star systems are so close to their companion that their orbital paths are comparable to the size of our Sun and they make a full orbit in less than a day. The orbital path of J1930-1852 spans about 52 million kilometers, roughly the distance between Mercury and the Sun and it orbits its companion once every 45 days. “Its orbit is more than twice as large as that of any previously known double neutron star system,” said Swiggum. “The pulsar’s parameters give us valuable clues about how a system like this could have formed. Discoveries of outlier systems like J1930-1852 give us a clearer picture of the full range of possibilities in binary evolution.”
Studies involving Pulsar Search Collaboratory discoveries are ongoing; as the PSC program continues, astronomers expect the 130 terabytes of data produced by the 17-million-pound GBT will likely reveal dozens of previously unknown pulsars.  
The Pulsar Search Collaboratory is a joint project between the National Radio Astronomy Observatory and West Virginia University. The goal is to give high school students experience doing real research.  
“This experience taught me that you do not have to be an 'Einstein' to be good at science,” said McGough, who is now a Schreyer Honors College scholar at Penn State University in State College majoring in astronomy and astrophysics and physics. “What you have to be is focused, passionate, and dedicated to your work.”
"As we look up into the sky and study the universe, we try to understand what’s out there,” said Ray, currently a student at the Community College of Baltimore County studying biology, engineering, and emergency medical services. “This experience has helped me to explore, to imagine, and to dream what could be and what we haven’t seen.”
The 100-meter Green Bank Telescope is the world's largest fully steerable radio telescope. Its location in the National Radio Quiet Zone protects the incredibly sensitive telescope from unwanted radio interference, enabling it to perform unique observations.
The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.
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Data from the 100-meter Robert C. Byrd Green Bank Telescope revealed the telltale signal of a previously unknown pulsar, which was determined to have the widest orbit ever observed around a companion neutron star. Credit: NRAO/AUI/NSF
Quelle: NRAO

Tags: Astronomie 

1764 Views

Samstag, 2. Mai 2015 - 18:18 Uhr

Raumfahrt - Eine Reise zum Mars könnte bei Astronauten Hirnschädigung durch kosmische Strahlung verursachen

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A Trip to Mars Could Give You Brain Damage
Exposure to cosmic rays may cause defects that would make astronauts lose their curiosity during a mission
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Space can be a dangerous place for fragile humans. Those willing to venture into Earth's orbit must negotiate health hazards such as extreme temperatures, cramped quarters, long periods of isolation and the debilitating physiological effects of life without gravity. Things will get even rougher for astronauts hoping to travel to an asteroid or Mars.
One of the greatest threats of deep-space travel is prolonged exposure to unrelenting cosmic radiation, which can damage DNA and increase a space traveler's chances of developing diseases such as cancer in their lifetime. Now, research in mice suggests that the first people to attempt a Mars mission will have a more immediate problem: brain damage. Cosmic rays bombarding the brain may result in cognitive and memory impairments that will manifest in just a few months.
Galactic cosmic radiation is made of high-energy particles originating from past supernova explosions that come zipping through our solar system. NASA has sponsored numerous studies investigating the short-term and long-term effects of space radiation on each system in the body, revealing that these rays can have a devastating effect on biological tissue over a lifetime.
Previous studies suggested that radiation exposure could also cause cognitive impairment, including earlier onset of Alzheimer's-like dementia. Now Charles Limoli, a professor of radiation oncology at the University of California Irvine School of Medicine, and his team have demonstrated that even relatively low doses of cosmic rays will induce a specific series of neural abnormalities that could manifest themselves during a round-trip mission to Mars, which is predicted to last for two to three years.
“This is the first study, in my opinion, that really ties a lot of loose ends together and provides a mechanism for what’s going on to cause cognitive dysfunction,” says Limoli, whose team reports the results today in Science Advances.
To study the “mind numbing” effects of radiation, the researchers examined several groups of six-month-old mice—the approximate average age of astronauts in mouse years. The team blasted the mice with low or high doses of energetic charged particles similar to those found in galactic cosmic radiation. These particles displace electrons in living tissue that then trigger free radical reactions, which cause changes in the cells and tissues of the body. Although free radical reactions occur within milliseconds, the cellular abnormalities they cause take form over months or even years, so the researchers waited six weeks before testing the irradiated mice to allow the cellular mischief to unfold.
The results showed that irradiated mice were significantly impaired in their ability to explore new objects placed in their environment, a task that draws upon a healthy learning and memory system. “The animals that were exposed lost curiosity. They lost their tendency to explore novelty,” says Limoli.
Specifically, the team discovered radiation-induced structural changes in the medial prefrontal cortex, a brain region responsible for higher-order processes known to be engaged during memory tasks. Neurons in these impaired areas showed a reduction in the complexity and density of structures called dendrites, which act as antennae for incoming cellular messages and are essential for the efficient exchange of information throughout the brain. The research team also discovered alterations in PSD-95, a protein that is important for neurotransmission and is also associated with learning and memory.
The cellular changes in the dendrites were directly related to cognitive performance—the mice with the largest structural alterations had the poorest performance results. And although these deficiencies took time to manifest, they appear to be permanent.
Limoli notes that, while the work was done in mice, the damage seen in their study looks a lot like defects seen in human brains suffering from neurodegenerative conditions like dementia. “Because these types of changes have also been found in a range of neurodegenerative conditions and occur over the course of aging, it provides a logical backdrop for what radiation does to the brains of both rodents and humans,” says Limoli.
It's likely no one has seen these types of defects in today's astronauts because people working on the International Space Station are “protected by the Earth’s magnetosphere, which deflects anything that has a charge,” says Limoli. And while the astronauts that traveled to the moon were not protected by Earth’s magnetic embrace, their relatively short trips would have limited exposure levels to a fraction of those that would be experienced on a mission to Mars.
While the results of this experiment were striking, other experts emphasize that there is still a lack of sufficient data to make definitive conclusions about the effects of radiation of people. “A lot of the information we have has been extrapolated from studies of catastrophic events in World War II," says Nathan Schwadron, associate professor of space plasma physics at the University of New Hampshire. "We just don’t have a lot of knowledge about what happens to biological systems when exposed to high levels of radiation for prolonged periods. I think that there is a potential risk here, but we really just don’t understand it yet.”
So what is to be done? NASA is currently investigating more advanced shielding technologies that could better protect astronauts on long-term missions into deep space. Engineers could also alter the shielding capabilities within certain regions of the ship, such as where astronauts sleep, or fit people with specialized helmets for space walks, says Limoli.
Schwadron, whose research is primarily focused on the development advanced shielding, says the energy from galactic cosmic radiation is so high that it interacts with the shielding materials in potentially problematic ways. “What happens is that high-energy radiation hits the shield and then produces a bath of secondary particles. Neutrons are probably the primary example of this.” These high-energy particles can then interact with the body, inducing free radical reactions and subsequent tissue damage.
Moving forward, Limoli and his team plan to design experiments that more accurately simulate human exposure to galactic cosmic rays and investigate alternative underlying mechanisms and cell types that could contribute to the proliferation of cognitive deficits. He is also investigating pharmacological interventions that could protect brain tissue from this radiation.
“We have some promising compounds that will probably help quite a bit,” says Limoli. “This is not a deal breaker—it is something that we need to understand and be aware of so we are not caught off guard.”
Quelle: Smithsonian

Tags: Raumfahrt 

1694 Views

Samstag, 2. Mai 2015 - 08:33 Uhr

Raumfahrt - Orion Fenster bieten Ausblick auf zukünftiges Raumschiff

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Orion’s windows are pictured in this photograph taken Dec. 5, 2014 after the spacecraft splashed down in the Pacific Ocean following its successful first flight test
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When astronauts travel to an asteroid and toward Mars in NASA’s Orion spacecraft, they’ll get a tremendous view of their deep space destinations and of Earth through the spacecraft’s windows. NASA engineers are making sure those windows will be more structurally sound, lighter and cheaper than on previous spacecraft.
On spacefaring vehicles like the space shuttle and the International Space Station that have enabled humans to push the boundaries of exploration, windows have typically been made of multiple panes of glass. Orion is being developed to include interior panes of an acrylic plastic material, a change that is improving the windows’ integrity.
“Glass windowpanes have historically been part of the pressure shell on spacecraft that holds cabin pressure to keep the astronauts alive, and they also provided thermal protection from entry though Earth’s atmosphere,” said Lynda Estes, Orion window subsystem manager at NASA’s Johnson Space Center in Houston, where the Orion Program is managed for the agency. “But the insidious thing about glass is that it’s a poor structural material. If you put loads on it, it will lose strength over time, and if you get a ding on it, the strength is dramatically decreased. The spaceflight environment is one that unfortunately exploits these vulnerabilities.”
Because glass is not an ideal material to use in a spacecraft, engineers have been on the lookout for something better. Many structurally sound materials exist, but few are also transparent.
During the early stages of Orion development, a polycarbonate material was considered for some of the interior window panes, but it didn’t have the demanding optical properties needed for high resolution imagery. The acrylic material that has since been chosen for the spacecraft was selected because it provides a clear view and also has an inherent strength that can be quantified. Aquariums around the country are using the same material, protecting the animals and plants behind them from the wear and tear of millions of visitors traveling through exhibits and sometimes pressing up against them to get a closer look while also enduring the loads of water in the tanks.
Currently Orion has four windows on the crew module/back shell cone, and additional windows on the docking hatch and the side hatch that the crew will use. Each window on the cone has three panes. The innermost pane on the cone windows is acrylic. Acrylic panes flew in space during Orion’s first flight test in December 2014, and engineers will further test the thermal integrity of acrylic panes this year to determine whether Orion can move to windows made of two acrylic panes and one glass pane.
In the coming months, Estes and her team also will put acrylic panes through an evaluation known as a “creep test.” Acrylics can be susceptible to loading over long time spans, so the test will evaluate how a pane handles pressure loads during a 270-day period.
The work being done to incorporate acrylic panes into Orion is also helping to make the spacecraft lighter. Because the structural integrity is enhanced, and an inadvertent scratch or other damage to it won’t jeopardize its strength, a multitude of panes isn’t needed to provide redundancy. Reducing the number of panes in the Orion windows not only reduces the collective weight, but the acrylic material also is half as dense and doesn’t weigh as much as glass.
“For Orion’s flight test vehicle, the use of acrylic pressure panes reduced the weight of the window subsystem by more than 200 pounds,” said Estes. A change of the redundant thermal pane from glass to acrylic could yield 30 pounds of savings or more. Reducing mass lowers the cost of getting to space, since decreasing weight means less propulsion is required to get a spacecraft out of Earth’s atmosphere.
The move to acrylic panes also has provided cost savings because the plastic material is considerably less expensive than glass. The glass panes used on Orion have also provided savings—they were all manufactured from stock glass originally purchased for the Space Shuttle Program. At the retirement of the orbiters, Estes had these assets transferred to Lockheed Martin, NASA’s prime contractor for Orion. Building windowpanes from these assets will reduce the cost of the Orion glass flight panes by more than $2 million.
NASA’s work on the lightweight window materials for Orion has also been shared with the Commercial Crew Program facilitating the development of U.S. commercial crew space transportation systems to provide safe, reliable and cost-effective access to and from the International Space Station and low-Earth orbit. 
Enough testing has not yet been done to show that every pane can be made of the acrylic material, but the window modifications are providing a new outlook for Orion’s future.
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An infrared image shows the Orion crew module floating in the water about 600 miles southwest of San Diego at the end of its 2014 flight test.
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One of Orion’s windows is evaluated in a test fixture.
Credits: Lynda Estes
Quelle: NASA

Tags: Raumfahrt 

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Freitag, 1. Mai 2015 - 22:52 Uhr

Luftfahrt - Erfolgreicher Flugtest von NASA´s Zehn Elektromotor Antrieb Flugzeug

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magine a battery-powered plane that has 10 engines and can take off like a helicopter and fly efficiently like an aircraft. That is a concept being developed by NASA researchers called Greased Lightning or GL-10.
The team, at NASA's Langley Research Center in Hampton, Virginia, is looking at the idea initially as a potential unmanned aerial vehicle (UAV). "We have a couple of options that this concept could be good for," said Bill Fredericks, aerospace engineer. "It could be used for small package delivery or vertical take off and landing, long endurance surveillance for agriculture, mapping and other applications. A scaled up version -- much larger than what we are testing now -- would make also a great one to four person size personal air vehicle.""
The GL-10 is currently in the design and testing phase. The initial thought was to develop a 20-foot wingspan (6.1 meters) aircraft powered by hybrid diesel/electric engines, but the team started with smaller versions for testing, built by rapid prototyping.
"We built 12 prototypes, starting with simple five-pound (2.3 kilograms) foam models and then 25-pound (11.3 kilograms), highly modified fiberglass hobby airplane kits all leading up to the 55-pound (24.9 kilograms), high quality, carbon fiber GL-10 built in our model shop by expert technicians, " said aerospace engineer David North.
"Each prototype helped us answer technical questions while keeping costs down. We did lose some of the early prototypes to 'hard landings' as we learned how to configure the flight control system. But we discovered something from each loss and were able to keep moving forward."
During a recent spring day the engineers took the GL-10 to test its wings at a military base about two hours away from NASA Langley. The remotely piloted plane has a 10-foot wingspan (3.05 meters), eight electric motors on the wings, two electric motors on the tail and weighs a maximum of 62 pounds (28.1 kilograms) at take off.
It had already passed hover tests -- flying like a helicopter -- with flying colors. But now was the big hurdle -- the transition from vertical to forward "wing-borne" flight. As engineers who have designed full-scale vertical take off and landing tiltrotors such as the V-22 Osprey will tell you -- that is no easy task because of the challenging flight aerodynamics.
"During the flight tests we successfully transitioned from hover to wing-borne flight like a conventional airplane then back to hover again. So far we have done this on five flights," said Fredericks. "We were ecstatic. Now we're working on our second goal -- to demonstrate that this concept is four times more aerodynamically efficient in cruise than a helicopter."
Zack Johns is the GL-10's primary pilot. He says flying the ten-engine aircraft has its ups and downs, but it really flies more like a three-engine plane from a control perspective.
"All four engines on the left wing are given the same command," said Johns. "The four engines on the right wing also work in concert. Then the two on the tail receive the same command."
One other advantage to the GL-10 besides its versatile vertical take off and landing ability is its noise or lack of it. "It's pretty quiet," said Fredericks. "The current prototype is quieter than a neighbor mowing the law with a gas-powered motor."
The next step in the GL-10 test program is to try to confirm its aerodynamic efficiency, but first is a stop at the Association for Unmanned Vehicles Systems International 2015 conference in Atlanta May 4-7. The GL-10 will be the centerpiece of an exhibit showcasing some of NASA Langley's UAV research.
Part of that UAV research is for NASA Aeronautics' Unmanned Aircraft Systems Integration in the National Airspace System Project, led out of the Armstrong Flight Research Center in Edwards, California. Engineers from Armstrong will highlight project accomplishments and upcoming work in a booth in Atlanta. The goal of the project is to provide research results to reduce the technical barriers associated with integrating unmanned aerial vehicles into the skies.
Researchers from the Wallops Flight Facility in Wallops Island, Virginia will also be at the conference, highlighting unmanned aircraft for use in science missions. "Remotely piloted aircraft are enhancing NASA science investigations and serve as a platform to expand technology development for aircraft, cubesats and other platforms," said Wallops Director's Office official Mike Hitch.
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The GL-10 prototype takes off in hover mode like a helicopter.
Credits: NASA Langley/David C. Bowman
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The prototype successfully transitioned from hover to wing-borne flight during several test flights.
Credits: NASA Langley/Gary Banziger
Quelle:NASA

Tags: Luftfahrt 

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