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Sonntag, 5. Juli 2015 - 18:30 Uhr

Astronomie - Astronomen tippen auf Feuerwerk bei seltener Stern Begegnung im Jahr 2018

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Astronomers are gearing up for high-energy fireworks coming in early 2018, when a stellar remnant the size of a city meets one of the brightest stars in our galaxy. The cosmic light show will occur when a pulsar discovered by NASA's Fermi Gamma-ray Space Telescope swings by its companion star. Scientists plan a global campaign to watch the event from radio wavelengths to the highest-energy gamma rays detectable.

The pulsar, known as J2032+4127 (J2032 for short), is the crushed core of a massive star that exploded as a supernova. It is a magnetized ball about 12 miles across, or about the size of Washington, weighing almost twice the sun's mass and spinning seven times a second. J2032's rapid spin and strong magnetic field together produce a lighthouse-like beam detectable when it sweeps our way. Astronomers find most pulsars through radio emissions, but Fermi's Large Area Telescope (LAT) finds them through pulses of gamma rays, the most energetic form of light.  
J2032 was found in 2009 through a so-called blind search of LAT data. Using this technique, astronomers can find pulsars whose radio beams may not be pointed precisely in our direction and are therefore much harder to detect.
"Two dozen pulsars were discovered this way in the first year of LAT data alone, including J2032," said David Thompson, a Fermi deputy project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Nearly all of them would not have been found without Fermi."
Once they knew exactly where to look, radio astronomers also were able to detect J2032. A team at the Jodrell Bank Centre for Astrophysics at the University of Manchester in the U.K. kept tabs on the object from 2010 through 2014. And they noticed something odd.
"We detected strange variations in the rotation and the rate at which the rotation slows down, behavior we have not seen in any other isolated pulsar," said Andrew Lyne, professor of physics at the University of Manchester. "Ultimately, we realized these peculiarities were caused by motion around another star, making this the longest-period binary system containing a radio pulsar."
The massive star tugging on the pulsar is named MT91 213. Classified as a Be star, the companion is 15 times the mass of the sun and shines 10,000 times brighter. Be stars drive strong outflows, called stellar winds, and are embedded in large disks of gas and dust.
"When we discovered this pulsar in 2009, we noticed that it was in the same direction as this massive star in the constellation Cygnus, but our initial measurements did not give any evidence that either star was a member of a binary system," explained Paul Ray, an astrophysicist at the Naval Research Laboratory in Washington. "The only way to escape that conclusion was if the binary system had a very long orbital period, much longer than the longest known pulsar-massive star binary at the time, which seemed unlikely."
Following an elongated orbit lasting about 25 years, the pulsar passes closest to its partner once each circuit. Whipping around its companion in early 2018, the pulsar will plunge through the surrounding disk and trigger astrophysical fireworks. It will serve as a probe to help astronomers measure the massive star's gravity, magnetic field, stellar wind and disk properties.     
Several features combine to make this an exceptional binary. Out of six similar systems where the massive star uses hydrogen as its central energy source, J2032's has the greatest combined mass, the longest orbital period, and, at a distance of about 5,000 light-years, is closest to Earth.
"This forewarning of the energetic fireworks expected at closest approach in three years' time allows us to prepare to study the system across the entire electromagnetic spectrum with the largest telescopes," added Ben Stappers, a professor of astrophysics at the University of Manchester. 
Astronomers think the supernova explosion that created the pulsar also kicked it into its eccentric orbit, nearly tearing the binary apart in the process. A study of the system led by Lyne and including Ray and Stappers was published June 16 in the journal Monthly Notices of the Royal Astronomical Society.
Quelle: NASA

Tags: Astronomie 

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Sonntag, 5. Juli 2015 - 14:00 Uhr

Raumfahrt - Ankunft von Progress 60 bei ISS

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Russian Progress Ship Makes Space Station Delivery

The International Space Station's crew received a much-needed care package on Sunday, in the form of a robotic Russian Progress cargo capsule filled with more than three tons of essentials, experiments and other goodies.
The delivery at 3:11 a.m. ET, two days after the Progress was launched from Russia's Baikonur Cosmodrome in Kazakhstan, was particularly welcome because the previous two robotic resupply missions failed. That forced the crew to miss out on five and a half tons of cargo.
"Guys, congratulations, your cargo vehicle has arrived," Vladimir Solovyov, who's in charge of the space station's Russian segment, told the station's cosmonauts from Russian Mission Control near Moscow just after Sunday's docking.
"It just feels like Christmas in July," one of the Russians replied. "The presents are here."
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 Folgen
 
Scott KellyVerifizierter Account
‏@StationCDRKelly
The third time's the charm as the say! #Progress60 arrives overnight. Great news. #YearInSpace (with supplies!) 
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The Progress delivered almost a ton of propellant, half a ton of oxygen and water, and more than a ton and a half of other supplies and experiments. The space station's crew — including NASA's Scott Kelly and Russia's Gennady Padalka and Mikhail Kornienko — will be unloading the goods during the days ahead.
The successful shipment came after April's failure of a Progress resupply mission, due to a design flaw in the Soyuz rocket's upper stage; and the loss of a SpaceX Falcon rocket and its Dragon cargo capsule shortly after launch a week ago. The investigation into the SpaceX failure — the company's first major setback since it started resupplying the space station in 2012 — could take months to complete.
The Progress craft's successful flight clears the way for three more crew members — NASA's Kjell Lindgren, Russia's Oleg Kononenko and Japan's Kimiya Yui — to ride a Soyuz capsule to the station later this month. NASA says the station now has enough of a stockpile to see the crew through November, and a robotic Japanese HTV cargo transport is due to make yet another delivery in August. 
Quelle: NBC-News

Tags: Raumfahrt 

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Sonntag, 5. Juli 2015 - 13:30 Uhr

Raumfahrt-History - 1973: Skylab-3 Teil 2/2

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Aus dem CENAP-Archiv:

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Presse-Berichte über das Raumlabor Skylab in der Apollo-Ära

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Quelle: CENAP-Archiv

Tags: Raumfahrt 

1590 Views

Sonntag, 5. Juli 2015 - 13:00 Uhr

Raumfahrt-History - 1973: Skylab-3 Teil 1/2

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Aus dem CENAP-Archiv:

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Presse-Berichte über das Raumlabor Skylab in der Apollo-Ära

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Quelle: CENAP-Archiv


Tags: Raumfahrt 

1700 Views

Sonntag, 5. Juli 2015 - 11:45 Uhr

Raumfahrt-History - 1973: Skylab-2

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Aus dem CENAP-Archiv:

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Presse-Berichte über das Raumlabor Skylab in der Apollo-Ära

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Quelle: CENAP-Archiv

Tags: Raumfahrt 

1489 Views

Sonntag, 5. Juli 2015 - 10:15 Uhr

Raumfahrt-History - 1973: Skylab-1

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Aus dem CENAP-Archiv:

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Quelle: CENAP-Archiv




Tags: Raumfahrt 

1475 Views

Samstag, 4. Juli 2015 - 23:00 Uhr

Luftfahrt - Exaktes Fliegen der ARTIS-Hubschrauber - Auswertung der Kleeblattflüge

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Am Deutschen Zentrum für Luft- und Raumfahrt (DLR) forschen Wissenschaftler mit dem Autonomous Rotorcraft Testbed for Intelligent Systems (ARTIS) an der Technologie für das automatische Fliegen. Bereits im September 2014 wurden Flugversuche unternommen, bei denen der unbemannte Hubschrauber selbständig und präzise eine im Voraus berechnete Bahn fliegen musste: ein Kleeblatt.
"Die Kleeblattform ist eine sehr komplexe geometrische Form", so Johann Dauer vom DLR-Institut für Flugsystemtechnik. Und komplex bedeutet anspruchsvoll: Während des Fluges muss ARTIS permanent seine Richtung anpassen und erreicht nie einen stationären Zustand. Der Mensch greift während des Fluges nur im Notfall ein. Grundsätzlich fliegt der Hubschrauber völlig automatisch. Dauer erklärt: "ARTIS lernt während er fliegt dazu. Dadurch wird sein Flug von Versuch zu Versuch besser." Die jetzt ausgewerteten Flugdaten zeigen eine sehr hohe Genauigkeit: Weniger als zwei Meter wich ARTIS vom Kurs ab.
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Dynamische Optimierung
Mittlerweile braucht die Vorausberechnung einer Flugbahn nur noch wenige Sekunden. Das ist nicht selbstverständlich, schließlich muss die komplexe Hubschrauberdynamik so genau wie möglich berücksichtigt werden. Durch die schnelle interne Berechnung können äußere Einflüsse wie die Änderung von Windstärke und Windrichtung unmittelbar berücksichtig werden.
Die von Johann Dauer entwickelten Algorithmen beziehen zudem die sogenannten Betriebsgrenzen des Hubschraubers mit ein. Bereits vor dem Flug kann festgestellt werden, ob der Hubschrauber unter den aktuellen Umständen seinen Flug überhaupt gefahrlos antreten kann. Vorgegeben werden bei diesem Verfahren nur noch die zu fliegende Geometrie und weitere Anforderungen an den Flug wie beispielsweise die Fluggenauigkeit. Wie ARTIS diese Anforderungen im Rahmen seiner Betriebsgrenzen anschließend umsetzt, berechnet er dann selbst in der dynamischen Optimierung.
Forschungsziel von ARTIS ist, dass Hubschrauber ihren Weg selbstständig finden - und das auch in hindernisreicher Umgebung wie etwa einer Stadt. Beeinträchtigungen durch Hindernisse oder Wind sollen autonom erkannt, ausgeglichen oder umflogen werden. Allgemein sind Hubschrauber hochkomplexe Maschinen mit starker Dynamik und vielen inneren Verkopplungen. Die genaue Vorhersage der Flugbewegung ist daher meist nicht einfach.
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Quelle: DLR

Tags: Luftfahrt 

1650 Views

Samstag, 4. Juli 2015 - 15:45 Uhr

UFO-Forschung - Warum gibt es keine Aliens Anrufe an die Erde?

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We’ve been conditioned by television and movies to accept the likelihood of intelligent life elsewhere in the universe. “Of course there’s intelligent life out there; I saw it last week on Star Trek.” We’ve seen it all, from the cute and cuddly ET to the fanged monstrosity of Alien.
But is it likely that we’re not alone in the universe? And if intelligent life is out there, why haven’t they contacted us yet?
The first person to address this question in a systematic way was Frank Drake, who invented the Drake equation to predict the number of extraterrestrial civilizations in the galaxy. His equation is rather complicated, but here’s a simple version of his argument.
First, let’s count how many stars are in the galaxy. To quote one of my predecessors, “Billions upon billions!” And how many of those stars have planets? Until recently, we really didn’t know. But over the past 20 years, astronomers have made remarkable progress in discovering planets around other stars. We now know that many stars have planets orbiting them.
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Could creatures actually live on any of those planets? Many of them are just giant balls of gas, or else too hot or too cold to contain liquid water, which is the basis of all life on Earth. But a few of them do seem to be at the right temperature. These are the Goldilocks planets: not too hot and not too cold for liquid water. (And that’s without even considering the possibility that exotic forms of life could survive without water.)
Now we enter murkier territory. How likely is it that life will develop on a potentially habitable planet? We don’t know the answer, but life on Earth got going very shortly after the formation of our solar system, and it has wedged itself into every available niche, no matter how hostile.
Colonies of bizarre creatures flourish in perpetual darkness near deep ocean vents, where superheated sulfur-rich water spews from under the ground. Radiation-resistant bacteria bask happily in levels of radioactivity that would instantly kill a human being. And then there’s the tardigrade, which looks like a microscopic eight-legged teddy bear, that can thrive in liquid nitrogen or boiling alcohol. So the probability of life developing on habitable worlds seems very high.
And how likely is it that this life will develop intelligence? This remains an open question (which is scientist-speak for “we haven’t got a clue”). But many scientists consider intelligent life almost inevitable, in which case the galaxy should be teaming with alien civilizations.
If the galaxy is crawling with aliens, where are they? Interstellar travel is limited by the speed of light, so maybe it’s no surprise that no one has visited us. But we should at least be able to detect alien radio signals, either from attempts to contact us directly, or in the form of alien TV reruns. Why haven’t our alien friends contacted us? This question was famously asked by the Italian physicist Enrico Fermi, so it’s called the Fermi paradox: all of our arguments suggest that alien civilizations should be common, yet we’ve seen no sign of them.
One possibility is that intelligent life really is rare. My own personal opinion (and it’s just an opinion) is that life is common, but intelligent life is rare (something many of us suspect based on our own experience). While life developed in the relative blink of an eye after the birth of the solar system, it took billions of years before we smarties showed up on the scene. And remember that “survival of the fittest” doesn’t always mean “survival of the smartest.” While intelligence is certainly a useful survival trait, it seems far from inevitable. If not for an errant asteroid, the dinosaurs might still rule the world.
Another possibility is that intelligent life inevitably destroys itself. Until recently, our options for total self-destruction were limited to nuclear weapons. But we are on the edge of expanding our armada to include genetically engineered viruses (think: Ebola meets the common cold!).
And consider the dangers posed by nanomachines, tiny self-replicating robots programmed to convert matter into more robots. Imagine a tiny robot, no bigger than the width of a human hair, designed to provide some useful function, programmed to build a copy of itself, using materials from its environment. Now you have two machines, and both can create duplicates, giving us four machines. But what if this process got out of control? The nanomachines could rapidly consume the entire Earth, converting it, along with everyone on the planet, into “grey goo.” British astronomer Martin Rees discusses these and other catastrophic possibilities in his book, Our Final Hour. Have all our potential alien visitors succumbed to self-destruction?
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Or is it possible that the galaxy really does contain other forms of intelligent life, but something prevents contact with us? Here we enter the realm of more speculative ideas. (Translation: when a scientist says “speculative,” it really means “a very interesting idea that’s only one step removed from complete nonsense.”)
Among the more speculative possibilities: maybe the galaxy is a dangerous place, full of robotic probes sent out by hostile aliens to wipe out any competition, so everyone else is in hiding. Perhaps we really shouldn’t have put a detailed description of the location of our solar system on our own space probes. It’s a bad idea to reach out and try to touch ET when we might get a call from the Alien instead.
An even more bizarre suggestion is that superior civilizations have decided to avoid contact with lesser beings such as ourselves, so that we live in a kind of cosmic zoo, complete with a “Do not talk to the animals” sign.
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Some have even suggested that we live in a gigantic computer simulation, a la The Matrix.
A longer list of possibilities (along with a skeptical discussion) has been compiled by astronomer Milan Ćirković.
Without more data, the Fermi paradox will remain, for now, unresolved, and many of the proposed solutions will have to be classified as “speculative.” And now you know exactly what that means.
Robert Scherrer is Professor and Chair of Physics and Astronomy at Vanderbilt University.
Quelle: SC

Tags: UFO-Forschung 

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Samstag, 4. Juli 2015 - 15:15 Uhr

Raumfahrt - NASA-Raumsonde Cassini begann am 1.Juli das zwölften Jahr in der Umlaufbahn von Saturn

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Neue Aufgaben für Cassini im 12.Umlaufbahn-Jahr um Saturn

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July 1 marked the beginning of the twelfth year in orbit about Saturn for NASA’s Cassini spacecraft, but this week also served as a reminder that the mission’s science extends far beyond our Solar System’s second-largest planet. So far, in fact, that much of Cassini’s work this week focused on understanding not the environment around Saturn, but that which encircles other stars. Our Solar System is not alone in the cosmos; at night the stars remind us that our Sun is but one amongst hundreds of billions in the Milky Way. Physical evidence of this is quite literally all around us. Just like the Earth moves in orbit around the Sun, the Sun—and everything around it—is in orbit about the center of the galaxy. As we complete our 200-million-year journey around the Milky Way, the area of space dominated by the Sun plows through a cloud of material cast off by our galactic neighbors. The density of these particles within the Solar System is astonishingly low. On its three-and-half-year cruise between Jupiter and Saturn, Cassini logged nearly 500 collisions between its Cosmic Dust Analyzer (CDA) and particles in space. Of those, only six were candidates for being so-called interstellar dust particles (IDPs). Six collisions in 1,278 days of travel! Cassini took five days this week to carry out further dust studies, simultaneously looking at particles originating in the Saturnian system and hoping to stumble upon another of these elusive interstellar travelers.  IDPs are incredibly small; some are comprised of just a few molecules. When one strikes the CDA, its velocity, mass, electric charge, and composition are recorded. With knowledge of the spacecraft’s orientation, researchers can work backwards to determine the path the particle must have taken. Orbits centered on the Sun probably have an origin close to home; those with exceptionally large orbits could have come from elsewhere in the galaxy. Grains of interstellar material were first found buried deep inside meteorites and represent our only contact with molecules that have existed since before the Sun formed more than four and a half billion years ago. The IDPs observed by Cassini, on the other hand, are much younger and probably represent the composition of interstellar space as it exists today. By understanding the material which surrounds our Solar System, scientists hope to gain new insight into the conditions experienced by forming stars. How the population of dust particles varies in interplanetary space could also shed light on how matter traverses the vast cosmic distances. The Cassini-Huygens mission is a collaborative effort between NASA, ESA, and the Italian Space Agency. Launched in 1997, it reached Saturn in 2004 and has since been studying the planet, its moons, and its rings. In 2005, the Huygens probe made the first landing on Titan, Saturn’s largest moon. After completing its second mission extension in 2017, Cassini will make a series of close passes to the planet and then end its time at Saturn by plunging into the planet’s atmosphere.

Quelle: SEN


Tags: Raumfahrt 

1657 Views

Samstag, 4. Juli 2015 - 14:45 Uhr

Raumfahrt - Spaces plant zweiten Test des Startabbruchsystem der Dragon Kapsel auf KSC

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SpaceX now plans to launch a test of an important astronaut safety system from Kennedy Space Center instead of California.
The second test of a Dragon capsule’s launch abort system will lift off from KSC’s historic pad 39A atop a Falcon 9 rocket.
The timing of the “in-flight abort” test is unknown, especially after the first failed Falcon 9 launch on Sunday, more than two minutes after a liftoff from Cape Canaveral Air Force Station.
The test was once planned this fall from Vandenberg Air Force Base in California. But under a revised agreement with NASA, it has been shifted to occur after SpaceX launches a Crew Dragon prototype on an unmanned orbital test flight, possibly by late 2016.
The change allows with Dragon returning from that orbital test flight to be used for the in-flight abort test.
That is preferable because that Dragon will be more like the Dragon astronauts are supposed to fly to the International Space Station than the model used in the first abort test on May 6, which fired its own thrusters to launch without a rocket from Cape Canaveral’s Launch Complex 40.
The in-flight abort test, again flown without people on board, aims to demonstrate the Dragon’s ability to move a crew away from a failing rocket as it flies through peak aerodynamic stress, then parachute to a splashdown in the Atlantic Ocean.
The launch escape system is designed to save astronauts from the type of malfunction that caused the Falcon 9 to break apart last Sunday, destroying an unmanned Dragon and its ISS cargo. Falcon 9s have flown successfully 18 times.
NASA’s Commercial Crew Program last year awarded SpaceX and Boeing contracts worth up to $2.6 billion and $4.2 billion, respectively, to start flying four-person crews to the space station by late 2017.
After a crewed test flight, the contracts guarantee each company at least two missions to and from the ISS.
SpaceX plans to launch astronauts from pad 39A at KSC. Boeing’s CST-100 capsule will fly atop United Launch Alliance’s Atlas V rocket from Cape Canaveral Air Force Station.
Cape launches continue
SpaceX’s launch failure last Sunday means Falcon 9 rockets will likely be grounded for months while the cause is investigated, but that doesn’t mean an end to launch activity at Cape Canaveral.
United Launch Alliance could showcase its two main rockets, the Atlas V and Delta IV, within a week of each other this month, if schedules hold.
An Atlas V is targeting a July 15 liftoff from Launch Complex 41 with the 10th in a series of a dozen Global Positioning System satellites. The rocket has flown 54 times without a major failure.
A Delta IV is scheduled to fly July 22 with a military communications satellite called WGS-7. The Delta IV has flown 29 times.
Another Atlas V is expected to launch in August.
The Navy communications satellite it will carry, called MUOS-4, recently was shipped from California to Cape Canaveral Air Force Station by a C-5 Galaxy aircraft.
Built by Lockheed Martin, the third Mobile User Objective System satellite launched in January. The four-spacecraft network is expected to be operational by the end of the year.
Pluto mania builds
NASA’s New Horizons spacecraft, launched from Cape Canaveral more than nine years ago, is less than two weeks from the first flyby of the dwarf planet at the far end of our solar system.
Mission managers last week decided against a final correction to the spacecraft’s path through the Pluto system, where it will make its closest in encounter to Pluto on July 14.
Because New Horizons is traveling at 30,800 mph, the flight team searched for any obstacles that might pose a hazard to the spacecraft. The last opportunity to shift its trajectory was on July 4.
“We are ‘go’ for the best of our planned Pluto encounter trajectories,” said Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado, the mission’s principal investigator.
“As a scientist I’m a bit disappointed that we didn’t spot additional moons to study, but as a New Horizons team member I am much more relieved that we didn’t find something that could harm the spacecraft,” says John Spencer, also of SwRI, who leads the hazard analysis team. “New Horizons already has six amazing objects to analyze in this incredible system.”
Happy anniversary?
Wednesday marks the fourth anniversary of the final space shuttle mission’s launch from Kennedy Space Center.
A four-person crew led by Chris Ferguson blasted off in Atlantis at 11:29 a.m. from launch pad 39A to start a 13-day mission, labeled STS-135, to the International Space Station.
Atlantis is now the centerpiece of a $100 million exhibit at the KSC Visitor Complex. SpaceX has leased pad 39A and is renovating it to support future launches of astronauts in Dragon capsules. Ferguson is part of a Boeing team readying CST-100 capsules to fly crews from next door at Launch Complex 41.
Whenever Boeing or SpaceX is ready to fly crews, they will end the gap in launches of astronauts from U.S. soil that began four years ago this month.
Happy Fourth from space
NASA astronaut Scott Kelly wished Americans a happy Independence Day from the International Space Station.
The retired Navy captain, now about a quarter of the way through a planned yearlong mission aboard the ISS, might have seen more fireworks shows than anyone.
“Hopefully the timing will be right and I’ll be able to look down and see little specks of light over the United States on the evening of the Fourth of July,” Kelly told NASA TV. “We’ll have to see how orbital mechanics and such works out.”
Quelle: Florida Today

Tags: Raumfahrt 

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