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Sonntag, 24. April 2016 - 21:15 Uhr

Raumfahrt - Mars-Curiosity-Chroniken - Curiosity-News Sol 1260-1263

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NASA's Mars rover Curiosity acquired this image using its Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover's robotic arm, on February 21, 2016, Sol 1260 of the Mars Science Laboratory Mission, at 19:01:01 UTC.
When this image was obtained, the focus motor count position was 12582. This number indicates the internal position of the MAHLI lens at the time the image was acquired. This count also tells whether the dust cover was open or closed. Values between 0 and 6000 mean the dust cover was closed; values between 12500 and 16000 occur when the cover is open. For close-up images, the motor count can in some cases be used to estimate the distance between the MAHLI lens and target. For example, in-focus images obtained with the dust cover open for which the lens was 2.5 cm from the target have a motor count near 15270. If the lens is 5 cm from the target, the motor count is near 14360; if 7 cm, 13980; 10 cm, 13635; 15 cm, 13325; 20 cm, 13155; 25 cm, 13050; 30 cm, 12970. These correspond to image scales, in micrometers per pixel, of about 16, 25, 32, 42, 60, 77, 95, and 113.
Most images acquired by MAHLI in daylight use the sun as an illumination source. However, in some cases, MAHLI's two groups of white light LEDs and one group of longwave ultraviolet (UV) LEDs might be used to illuminate targets. When Curiosity acquired this image, the group 1 white light LEDs were off, the group 2 white light LEDs were off, and the ultraviolet (UV) LEDS were off. 
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1260 (2016-02-21 21:39:46 UTC). 
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This image was taken by Navcam: Right B (NAV_RIGHT_B) onboard NASA's Mars rover Curiosity on Sol 1260 (2016-02-21 21:46:50 UTC).
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This image was taken by Rear Hazcam: Left B (RHAZ_LEFT_B) onboard NASA's Mars rover Curiosity on Sol 1260 (2016-02-21 21:37:25 UTC). 
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This image was taken by Navcam: Left B (NAV_LEFT_B) onboard NASA's Mars rover Curiosity on Sol 1261 (2016-02-22 21:57:44 UTC). 
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This image was taken by Mastcam: Right (MAST_RIGHT) onboard NASA's Mars rover Curiosity on Sol 1262 (2016-02-23 22:26:31 UTC).
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This image was taken by Mastcam: Left (MAST_LEFT) onboard NASA's Mars rover Curiosity on Sol 1262 (2016-02-23 22:28:04 UTC). 
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This image was taken by Rear Hazcam: Right B (RHAZ_RIGHT_B) onboard NASA's Mars rover Curiosity on Sol 1263 (2016-02-24 21:21:51 UTC). 
Quelle: NASA

Tags: Raumfahrt 

1112 Views

Sonntag, 24. April 2016 - 16:25 Uhr

Luftfahrt - History des Langley Wind Tunnel: Cave of the Winds - Fortsetzung

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Quelle: NASA

Forsetzung...


Tags: Luftfahrt 

1438 Views

Sonntag, 24. April 2016 - 15:15 Uhr

Astronomie - Das Geheimnis der Phantom Galaxien vielleicht schon bald gelöst

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A new theory says these mysterious “ultradiffuse” oddball galaxies are dwarfs born in a whirl

Ultradiffuse galaxies seem to be the same size as giant galaxies, like the magnificent spiral galaxy M81 pictured here. But unlike giant galaxies, which can contain hundred of billions or even trillions of stars, ultradiffuse ones harbor only tens to hundreds of millions. The origins of the ghostly galaxies remain mysterious. Credit: NASA/ESA/STScI/AURA
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Astronomers have long recognized that galaxies come in a variety of forms, and that any galaxy’s size and shape offer a glimpse of its history. A fast-spinning giant galaxy whips up a beautiful spiral pattern like that of our familiar Milky Way; if two giant spiral galaxies collide, they may become an even bigger star swarm called an elliptical galaxy. Around all these mighty giants, diminutive “dwarf” galaxies dance by the dozens—these may be leftovers from the giants’ formation. Recently, however, observers have uncovered enormous numbers of galaxies in an odd new form that is not so easily explained.
In 2014 astronomers led by Pieter van Dokkum of Yale University pointed a sensitive array of small telescopes at a galaxy cluster in the constellation Coma Berenices and were astonished to discover 47 “smudges” all over the resulting images. The smudges were not somebody's fingerprints; they were ghostly galaxies that appeared to be bizarre hybrids of giants and dwarfs. Like giants, they were as large as the Milky Way; like dwarfs, they were dim, emitting roughly a thousandth as much light. The two opposing traits account for their strange appearance: They look dim and ghostly because their relatively few stars are spread out over a huge volume of space.
Moreover, these “ultradiffuse” galaxies proved to be surprisingly common. When astronomers looked more closely at the Coma cluster using the 8.3-meter Subaru Telescope, they spotted more than 800 additional examples, and searches through archival data revealed that the first few members of the class appeared in observations from the 1980s. Faced with so many oddities, theorists are now crafting new models to explain how this profusion of galactic phantoms arose.
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Pale and ghostly, ultradiffuse galaxies, such as this one in the Coma Cluster, abound in large numbers, but no one knows exactly how they arose.
Credit: Hubble Space Telescope. NASA, ESA and Pieter van Dokkum (Yale University) et al
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Van Dokkum’s favored scenario is that ultradiffuse galaxies are failed giants. In this model galaxies as massive as the Milky Way failed to light up because they had the misfortune to fall into a galaxy cluster, which stripped them of their gas. Without large amounts of gas, such galaxies could not spawn new stars, so these giants faded into their present dim, diffuse state.
Now, however, Nicola Amorisco and Avi Loeb of the Harvard–Smithsonian Center for Astrophysics have proposed a different idea to explain ultradiffuse galaxies. “They are dwarf galaxies,” Amorisco says. “This is what allows them to be so numerous.”
The key to the new proposal is spin. Different dwarf galaxies are born spinning at different speeds. As a large object—galaxy, star or planet—contracts under the force of gravity, the conservation of angular momentum magnifies any slight initial rotation into a significant, measurable spin. If a dwarf happens to be born spinning slowly, gas plunges toward the galaxy's center, forming stars over a compact region. But if a dwarf is born spinning fast, infalling gas instead keeps its distance from the galaxy’s center, forming stars over a much larger volume. In the new proposal, which Amorisco and Loeb recently published in Monthly Notices of the Royal Astronomical Society, ultradiffuse galaxies are the dwarfs born spinning so fast they formed their stars over a truly vast expanse. “I like the idea, because it’s testable,” van Dokkum says. “I kind of hope it’s not true, because to me it’s a less interesting option” than the failed-giant scenario.
The new theory makes a simple prediction about ultradiffuse galaxies: If they are dwarfs, “they should be everywhere,” Amorisco says. In contrast, if the galaxies are failed giants that owe their existence to the gas-stripping influence of galaxy clusters, then galaxy clusters should be the only cosmic homes for ultradiffuse galaxies. Galaxy clusters have so much gravitational pull that they are hard to escape—once a galaxy falls in, it cannot climb back out. So far, nearly all known ultradiffuse galaxies have turned up in clusters rather than in more modest galactic gatherings known as groups, but others may pop up elsewhere as astronomers begin to search for them more thoroughly.
Another way to distinguish between failed giants and fast-spinning dwarfs is to measure the mass of an ultradiffuse galaxy—something that Michael Beasley of the Institute of Astrophysics of the Canary Islands and his colleagues recently accomplished. Beasley’s galaxy lies in the Virgo Cluster of galaxies and is about 8 percent as massive as the Milky Way. According to Loeb, this supports the idea that the galaxy formed as a fast-spinning dwarf, but van Dokkum says the galaxy is anomalously dim even by ultradiffuse standards, making it an unsuitable outlier from which to make major extrapolations about the class as a whole. “It’s fascinating that people cite the same galaxy to support such different ideas,” van Dokkum says.
Normally, such a ghostly galaxy would be too difficult for observers to weigh but Beasley's team circumvented that problem by measuring how fast seven bright globular star clusters are orbiting the galaxy. Van Dokkum says the very prescence of globular clusters supports his view that ultradiffuse galaxies are giants, because most dwarf galaxies don't have any. But Amorisco counters that Beasley’s galaxy has far fewer globular clusters than giant galaxies typically do.
Van Dokkum hopes to have an answer soon. During January, March and April of this year, he and his collaborators stared at three ultradiffuse galaxies in the Coma Cluster with the mammoth Keck Telescope for a lengthy 34 hours. “That's what it takes,” he says. After analyzing the data, he should know how fast the stars of those galaxies move, and thus how massive their hosts are—revealing whether or not this newly recognized breed of galaxies are fast-spinning dwarfs or instead a race of giants that failed to shine. Stay tuned.
Quelle: SCIENTIFIC AMERICAN

Tags: Astronomie 

1423 Views

Sonntag, 24. April 2016 - 14:45 Uhr

Raumfahrt - ISS-ALLtag: LIVE: Tim Peake "läuft" London-Marathon im Weltraum

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Mr Peake will start at the same time as the other runners on 24 April
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UK astronaut Tim Peake is running the distance of the London Marathon on a treadmill in the International Space Station (ISS).
To counteract the effects of weightlessness, he is using a harness to keep him on the running belt.
He will run the standard 42km (26.2mi) distance and started at the the same time as other competitors on 24 April.
"I'm really looking forward to this - it's a great challenge," said Major Peake, before the event.
"I'm quite glad that this is happening later on in the mission so I've had plenty of time to get used to the T2 treadmill."
Elastic straps over the shoulders and round the waist keep Major Peake in contact with the running belt of the treadmill, located in the station's Tranquility Node.
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"It's like running with a clumsy rucksack on" - Tim Peake explains how this harness will enable him to run the London Marathon while in space
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The straps are designed to generate the foot force necessary to give astronauts' bones and muscles a workout in weightlessness.
He said: "One of the biggest challenges is the harness system. Obviously, my bodyweight has to be firmly attached to the treadmill by this harness, and that can rub on the shoulders and around the waist."
The Chichester-born astronaut ran the London Marathon in 1999, finishing in three hours, 18 minutes and 50 seconds.
But he will not try to beat that time as his medical team wants to ensure he is perfectly healthy for his return to Earth in June.
The ISS is circling the Earth at a relative velocity of 28,800km/h (17,900mph), so Major Peake is likely to cover about 100,000km (60,000mi) during his run.
He said he did not think he would be setting any personal bests, but said he would aim to complete the course in under four hours.
Major Peake started at the same time as the other runners: 10:00 BST on 24 April.
Quelle: BBC

Tags: Raumfahrt 

1463 Views

Sonntag, 24. April 2016 - 11:45 Uhr

Mars-Chroniken - Erste direkte Spuren von sauerstoffreichen Atmosphäre des alten Mars

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Rocks on the surface of Mars have yielded the best clue yet that the planet once had an atmosphere rich in oxygen.
Mars owes its sobriquet “the Red Planet” to the abundance of iron oxide, otherwise known as rust, on its surface. But in addition to all that iron, NASA’s Curiosity rover has now found substantial amounts of manganese oxide in rocks in Mars’s Gale crater.
“We found 3 per cent of rocks have high manganese oxide content,” Agnès Cousin of the Research Institute in Astrophysics and Planetology in Toulouse, France, told the European Geophysical Union meeting in Vienna, Austria, earlier this week. “That requires abundant water and strongly oxidising conditions, so the atmosphere may have contained much more oxygen than we thought.”
Mars’s current atmosphere is 95 per cent carbon dioxide and contains only trace amounts of oxygen. Nevertheless, many researchers have argued that Mars must once have been rich in atmospheric oxygen. This is the most direct evidence to date, the Curiosity team claim.
The rover identified the manganese oxide with the help of its ChemCam, an instrument which zaps rocks with a laser and analyses the resulting dust cloud to identify chemicals and minerals. The researchers haven’t yet pinned down the exact age of the manganese oxide, but hope to do so with future data from the rover.
Because many of the manganese oxide deposits are close to where a lake once existed in the crater, Cousin says that flowing liquid with dissolved oxygen in it may have played a part in its formation. “It’s a real possibility that there was oxygen in the atmosphere, and possibly water available locally that was oxidising,” she says.
If there was too much oxygen, though, it might not have been a good thing for early life, says Damien Loizeau of the University of Lyon, France. On Earth, oxidation breaks up biological molecules. The appearance of oxygen on Earth was linked to organisms that produced it, but was a disaster for those organisms’ neighbours.
“O2 is bad for life as we know it, but we only know life to be able to create large amounts of O2,” he says.
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Two pictures of rock samples on Mars with scale bars indicating size
Two especially manganese-rich samples, imaged by ChemCam
Quelle:NewScientist

Tags: Mars-Chroniken 

1463 Views

Sonntag, 24. April 2016 - 11:30 Uhr

Raumfahrt - Umgebungseinflüsse Test für JPSS 1 haben begonnen / Start 2017

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The next American polar-orbiting weather satellite that will feed long-range forecasts and track environmental trends has slipped into space-like testing ahead of launch.
The Joint Polar Satellite System spacecraft No. 1 will be launched atop a United Launch Alliance Delta 2 rocket from Vandenberg Air Force Base in California on Jan. 20 at 1:47 a.m. local (4:47 a.m. EST; 0947 GMT).
The project is a collaboration between the National Oceanic and Atmospheric Administration (NOAA) and NASA.
From a 512-mile orbit, tilted 98.7 degrees to the equator and traveling pole-to-pole, JPSS 1 will survey the entire globe twice per day with five sensor packages.
The craft will provide imagery, atmospheric temperature and humidity profiles, and land and ocean surface temperature observations, all of which are key ingredients for weather forecasting. In addition, the satellite will measure ozone levels and reflected solar radiation from the planet.
The satellite will replace the existing Suomi NPP spacecraft that launched in 2011 for a five-year mission as a gapfiller between NOAA’s legacy weather satellite constellation and the new JPSS generation.
JPSS 1 will be renamed NOAA 20 once declared operational. It is designed to last seven years.
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JPSS 1 artist’s concept. Credit: Ball
Spacecraft manufacturer Ball Aerospace has begun environmental testing at the company’s Fisher Complex in Boulder, Colorado, to simulate the harsh conditions that JPSS 1 will face during its launch and once in orbit.
Tests include acoustic, vibration and electromagnetic interference and electromagnetic compatibility, followed this summer by thermal vacuum testing to expose the craft and instruments to the extreme temperature swings experienced in space.
All of the checks will culminate with certification that the satellite is ready to ship to its California launch site this fall.
“Heading into the final series of environmental tests marks completion of the development and integration phase, on time and on schedule,” said Jim Oschmann, vice president and general manager for Ball’s Civil Space business unit.
“We look forward to having the next polar-orbiting satellite on-orbit to ensure continuous coverage of precise and timely weather information.”
JPSS 1 will be the next-to-last flight for the venerable Delta 2 rocket.
Quelle: SN

Tags: Raumfahrt 

1129 Views

Sonntag, 24. April 2016 - 11:15 Uhr

Planet Erde - Kern der Erde ist zwei-und-ein-halb Jahre jünger als ihre Kruste

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There’s a surprise lying deep beneath your feet. Physicists have calculated that the centre of the Earth is two-and-a-half years younger than its surface, thanks to the effects of gravity as described by general relativity.
According to Einstein’s theory, your position in a gravitational field changes the rate at which you experience time passing. The idea has been rigorously tested and has an impact on GPS satellites. But the time differences involved here are normally fractions of a second, not a couple of years.
Ulrik Uggerhøj of Aarhus University in Denmark and his colleagues realised the effect would be much more pronounced for Earth after re-examining a claim made by physicist Richard Feynman in the 1960s. In a series of lectures, Feynman claimed that the difference in age between the Earth’s centre and surface was about a day or two – a figure often repeated and cited in papers by other physicists, including Uggerhøj.
But when Uggerhøj recently decided to include the anecdote in an undergraduate textbook, he sat down to check the figure himself. The calculation involves working out the difference in gravitational potential – a measure of the work done by gravity in moving a mass from one location to another – between the centre and surface.
Young at heart
Plugging this difference into the equations of relativity gives a time dilation factor of around 3 x 10-10, meaning every second at the Earth’s centre ticks this much slower than it does on the surface. But since the Earth is around four billion years old, the cumulative effect of this time dilation adds up to a difference of around a year and a half.
These calculations assume a uniform density throughout the Earth, which we know isn’t accurate since the core is denser than the mantle. Using a more realistic model of Earth’s density, Uggerhøj’s team found the difference in age is actually around two-and-a-half years.
Of course, we can’t confirm this number experimentally, says Uggerhøj. But general relativity has passed every test thrown at it so far, so it seems likely to be correct. And since, as far as we know, the theory operates throughout the universe, the same effect occurs for any massive body. The team calculates that the centre of the sun is around 40,000 years younger than its surface.
Uggerhøj says it is unclear whether Feynman made the error originally, or whether the transcription of his lectures somehow garbled “days” into “years”, but he says it pays to take nothing for granted. “One should always be cautious and test even famous people’s suggestions,” he says. “I fell into the trap of not doing it, I must admit.”
Quelle: NewScientist

Tags: Planet Erde 

1635 Views

Sonntag, 24. April 2016 - 11:10 Uhr

Astronomie - Alte Zwerggalaxie war Schwerelementfabrik

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HEAVY METALS  Scientists observed nine stars (circled) in the dwarf galaxy Reticulum II. Their data (shown for three stars) indicated the presence of heavy elements, formed through a sequence of reactions known as the “r-process.”
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SALT LAKE CITY — In the primeval universe, a violent event roiled a dwarf galaxy, leaving an indelible mark on the stars that formed there. Scientists reached that conclusion after finding traces of heavy elements produced by the cataclysm in the ancient dwarf galaxy Reticulum II.
“It might be the first time where we can distinctly point to something and say, ‘One thing happened in this galaxy 13 billion years ago,’” says Alexander Ji of MIT, who presented the research April 19 at a meeting of the American Physical Society.
Many of the universe’s heaviest elements form primarily through the r-process, a chain of reactions through which atomic nuclei climb the periodic table, swallowing up neutrons and decaying radioactively. But scientists don’t agree on where the seeds of these heavy elements are sown, except that it must be an environment rich in neutrons.
Ji and collaborators used the Magellan telescopes in Chile to perform their “stellar archaeology,” cataloging chemical elements in nine of Reticulum II’s stars. Seven of those stars contained heavy elements, like europium, gadolinium and neodymium, in just the proportions produced by the r-process.
Since most similar dwarf galaxies show no conclusive evidence of r-process elements, the scientists deduced that the event must be rare. This restriction helped pin down what event produced the elements, eliminating relatively common occurrences such as a type of exploding star known as a core-collapse supernova. Instead, the progenitor was probably a collision of two neutron stars, or a rare type of stellar explosion that spews jets of material, the researchers say.
Quelle: ScienceNews

Tags: Astronomie 

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Samstag, 23. April 2016 - 21:15 Uhr

Luftfahrt - NASA startet historische neue Ära der X-Plane Forschung

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The Quiet Supersonic Technology, or QueSST, concept is in the preliminary design phase and on its way to being one of NASA’s first X-planes.
Credits: NASA
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“There was a demon that lived in the air. They said whoever challenged him would die. Their controls would freeze up. Their planes would buffet wildly and they would disintegrate.
The demon lived at Mach 1 on the meter, 750 miles an hour, where the air could no longer move out of the way. He lived behind a barrier through which they said no man could ever pass. They called it the sound barrier.
Then they built a small plane, the X-1, to try to break the sound barrier. And men came to the high desert of California to ride it. They were called test pilots. And no one knew their names.”
– The Right Stuff (1984)
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History is about to repeat itself.
There have been periods of time during the past seven decades – some busier than others – when the nation’s best minds in aviation designed, built and flew a series of experimental airplanes to test the latest fanciful and practical ideas related to flight.
Short wings. Long wings. Delta-shaped wings. Forward swept wings. Scissor wings. Big tails. No tails. High speed. Low speed. Jet propulsion. Rocket propulsion. Even nuclear propulsion – although that technology was never actually flown.
Individually each of these pioneering aircraft has its own story of triumph and setback – even tragedy. Each was made by different companies and operated by a different mix of government organizations for a myriad of purposes.
Together they are known as X-planes – or X-vehicles, since some were missiles or spacecraft – and the very mention of them prompts a warm feeling and a touch of nostalgia among aviation enthusiasts worldwide.
“They certainly are all interesting in their own way. Each one of them has a unique place in aviation that helps them make their mark in history,” said Bill Barry, NASA’s chief historian. “And they are really cool.”
And now, NASA’s aeronautical innovators once again are preparing to put in the sky an array of new experimental aircraft, each intended to carry on the legacy of demonstrating advanced technologies that will push back the frontiers of aviation.
Goals include showcasing how airliners can burn half the fuel and generate 75 percent less pollution during each flight as compared to now, while also being much quieter than today’s jets – perhaps even when flying supersonic.
NASA’s renewed emphasis on X-planes is called, “New Aviation Horizons,” an initiative announced in February as part of the President’s budget for the fiscal year that begins Oct. 1, 2016. The plan is to design, build and fly the series of X-planes during the next 10 years as a means to accelerate the adoption of advanced green aviation technologies by industry.
“If we can build some of these X-planes and demonstrate some of these technologies, we expect that will make it much easier and faster for U.S. industry to pick them up and roll them out into the marketplace” said Ed Waggoner, NASA’s Integrated Aviation Systems Program director.
It’s something NASA has known how to do going way back to the days of its predecessor organization, the National Advisory Committee for Aeronautics (NACA), and the very first X-plane, fittingly called the X-1, a project the NACA worked on with the then newly formed U.S. Air Force.
Experiment Supersonic
Built by Bell Aircraft, the X-1 was the first plane to fly faster than the speed of sound, thus breaking the “sound barrier,” a popular but fundamentally misleading term that spoke more to the romantic notion of the challenges of high speed flight than an insurmountable physical wall in the sky.
As colorfully recounted in books and movies such as “The Right Stuff,” it was Oct. 14, 1947 when Air Force Capt. Chuck Yeager, dinged-up ribs and all, climbed into the bright orange Glamorous Glennis and flew the X-1 into its moment in history.
On that day the Antelope Valley, home to Edwards Air Force Base in California, reportedly echoed with its first sonic boom. But whether or not anyone there actually heard a sonic boom, thousands more echoed over the valley in the decades to come as supersonic flight over the military base became routine.
The X-1 also marked the first in what became a long line of experimental aircraft programs managed by the NACA (and later NASA), the Air Force, the Navy, and other government agencies.
The current list of X-planes that have been assigned numbers by the Air Force stands at 56, but that doesn’t mean there have been 56 X-planes.
Some had multiple models using the same number. And still more experimental vehicles were designed, built and flown but were never given X-numbers. And some X-vehicles received numbers but were never built.
The X-52 was skipped altogether because no one wanted to confuse that aircraft with the B-52 bomber.
Moreover, some X-planes weren’t experimental research planes at all, but rather prototypes of production aircraft or spacecraft, further muddying the waters over what is truly considered an X-plane and what isn’t, Barry said.
“They weren’t necessarily thinking there would be a series of X vehicles at the time of the X-1 because you wound up with several modifications, for example, including the A, the B models – which were very different vehicles in many ways,” Barry said.
Examples of experimental aircraft not called X-planes include some of NASA's lifting bodies, and the Navy’s D-558-II Skyrocket, which pilot Scott Crossfield flew in 1953 to become the first airplane to travel twice the speed of sound, or Mach 2.
And it gets even more confusing: some of the early X-planes were called the XS-1, XS-2 and so on – the XS being short for “experiment, supersonic.” Although it’s not clearly documented, at some point XS became X, because XS sounded too much like “excess,” as in something you don’t need, Barry said.
There also have been airplanes like the XB-70, a supersonic jet demonstrator considered an X-plane in most circles, but officially not part of the 56 X-planes numbered to date by the Air Force.
“In any case, while the X-plane designation has become a very amorphous term through history, it’s a term that people today now identify as being a cutting edge research sort of plane,” Barry said.
Perhaps of all the X-planes NASA has been associated with, none was more cutting edge and became more famous – rivaling even the X-1 – than the X-15 rocket plane.
“The X-1 was certainly the most historic for being the first and for what it did for supersonic flight. But the X-15 was probably the most productive model of an X-plane,” Barry said.
Flown 199 times between 1959 and 1968, the winged X-15 reached beyond the edge of space at hypersonic speeds, trailblazing design concepts and operational procedures that directly contributed to the development of the Mercury, Gemini, and Apollo piloted spaceflight programs, as well as the space shuttle.
Another component of the X-15 success story beyond its contributions to high-speed aviation, Barry explained, is that it was a great example of collaboration between NASA, the rival military services of the Air Force and the Navy.
“This kind of major aeronautical research, which the X-15 represented, often is best done when several organizations contribute to a common goal,” Barry said. “We’re already seeing that as we prepare to fly this next wave of X-planes.”
But in this age of high-speed computers capable of generating sophisticated simulations, and with the availability of world-class wind tunnels to test high-fidelity models, why still the need to fly something like an X-plane?
“It’s a valid question,” Waggoner said.
The answer has to do with what Waggoner describes as the necessity of a “three legged stool” when it comes to aviation research.
One leg represents computational capabilities. This involves the high-speed super computers that can model the physics of air flowing over an object – be it a wing, a rudder or a full airplane – that exists only in the ones and zeros of a simulation.
A second leg represents experimental methods. This is where scientists put what is most often a scale model of an object or part of an object – be it a wing, a rudder or an airplane – in a wind tunnel to take measurements of air flowing over the object.
Measurements taken in the wind tunnel can help improve the computer model, and the computer model can help inform improvements to the airplane design, which can then be tested again in the wind tunnel.
“Each of these is great on its own and each helps the other, but each also can introduce errors into the inferences that might be made based on the results,” Waggoner said. “So the third leg of the stool is to go out and actually fly the design.”
Whether it’s flying an X-plane or a full-scale prototype of a new aircraft, the data recorded in actual flight can then be applied to validate and improve the computational and experimental methods used in developing the design in the first place.
“Now you’ve got three different ways to look at the same problem,” Waggoner said. “It’s only through doing all that together that we will ever get to the point where we’ve lowered the risk enough to completely trust what our numbers are telling us.”
“Que” the Supersonic Technology
Although it may not wind up being the first of the New Aviation Horizons X-planes to actually fly as part of the three-legged stool of research, design work already has begun on QueSST, short for Quiet Supersonic Technology
A preliminary design contract was awarded in February to a team led by Lockheed Martin. If schedule and congressional funding holds, this new supersonic X-plane could fly in the 2020 timeframe.
QueSST aims to fix something the X-1 first introduced to the flying world nearly 70 years ago – the publicly annoying loud sonic boom.
Recent research has shown it is possible for a supersonic airplane to be shaped in such a way that the shock waves it forms when flying faster than the speed of sound generate a sonic boom so quiet it hardly will be noticed by the public, if at all.
The resulting sonic “boom” has variously been described as like distant thunder, the sound of your neighbor forcefully shutting his car door outside while you are inside, or as the thump of a “supersonic” heartbeat.
“We know the concept is going to work, but now the best way to continue our research is to demonstrate the capability to the public with an X-plane,” said Peter Coen, NASA’s supersonic project manager.
It is hoped data gathered from flying QueSST will help the Federal Aviation Administration and its international counterparts establish noise-related regulations that will make it possible for commercial supersonic airliners to fly over land across country.
“Providing that data will be a key step in bringing accessible and affordable supersonic flight to the traveling public,” Coen said.
Meanwhile, other experimental aircraft also are under consideration, including those with novel shapes that break the mold of the traditional tube and wing airplane, and others that are propelled by hybrid electric power.
Exactly what these X-planes will look like, how they will be operated and where they will be flown all have yet to be precisely defined.
“We’re going to let the marketplace and the community help us inform our decisions on the direction we want to go,” Waggoner said. “But we’re really excited about all of the things we might demonstrate.”
Interestingly, despite these future test aircraft being referred to as X-planes, it is entirely possible only some of them will actually get an official X-plane number designation – or perhaps none of them will.
“We just don’t know yet,” Waggoner said. “That decision likely won’t take place for each aircraft until we’re about to award the construction contract.”
So whether NASA winds up calling these new planes by an X-number or a catchy acronym – or both – one thing is clear: NASA’s flight research program is on its way to creating a renaissance of an exciting era in aviation research.
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Quelle: NASA

Tags: Luftfahrt 

1269 Views

Samstag, 23. April 2016 - 20:30 Uhr

Astronomie - Vollmond Spechteln am 21.April

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Fotos:©hjkc


Tags: Astronomie 

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