Blogarchiv

Sonntag, 21. August 2016 - 17:15 Uhr

Raumfahrt - Chinesische Wissenschaftler studieren Möglichkeit von Radarstation auf dem Mond

.

China has commissioned a group of scientists to study the feasibility of building a manned radar station on the moon, but many experts on the mainland have questioned the potentially massive cost of the project and the usefulness of building such a base.

The government project was launched earlier this year and received kick-start funding of 16 million yuan (HK$18.7 million) from the National Natural Science Foundation of China, according to its website.

 
 

 

The proposed facility, which may include quarters for astronauts and a powerful radar antenna array at least 50 metres high, could monitor wider areas of our planet than existing satellites, according to scientists involved in the study.

The base, which would be used for scientific research and defence monitoring, could also produce more powerful and clearer images of earth as the high-frequency microwaves emitted by the radar station could not only penetrate cloud, but also the earth’s surface, allowing it to monitor areas on land, under the sea and underground.

Leading space scientists in China have joined the radar station project.

The team held a two-day brainstorming session at the Fragrant Hill Hotel in Beijing last month.

Those taking part included Yan Jun, the director of the National Astronomical Observatories; Professor Lin Yangting, a planetary researcher whose team discovered evidence of coal-like carbon in an asteroid; and senior scientists from China’s unmanned lunar exploration missions.

The team leader is Professor Guo Huadong, a top radar technology expert at the Chinese Academy of Sciences.

 
 

 

Guo initially proposed the moon-based radar station in a research paper in the journal Science China Earth Sciencesthree years ago.

He suggested the moon had numerous advantages over satellites or a space station as an earth observation platform, including stability and the unlimited durability of any complex on the lunar surface.

The data collected by lunar radar would help with a wide range of scientific research issues such as monitoring extreme weather conditions, global earthquake activity, agricultural production and the collapse of the polar ice caps, he wrote.

To generate high intensity radio beams that could reach earth, the radar station would need an enormous amount of power so a solar or nuclear power plant would have to be built, Guo said in the paper.

The radar would generate at least 1.4 gigabytes of data each second, a volume far exceeding the bandwidth of current long-distance space communications technology, but this would not be a problem if the station was manned by astronauts who could process the information on site, he added.

Guo gave no precise estimate on costs for the project, but cautioned it would be “very expensive”. He did not respond to requests for comment.

Many researchers interviewed by the South China Morning Post, however, expressed scepticism about the scheme, arguing it was a waste of money, time and human resources.

“It’s a lunatic idea,” said one mainland space scientist informed of the project, but not directly involved.

The cost of building such as a large scale facility on the moon would be “higher than filling the sky with a constellation of spy satellites”, which could “do the same job at only a fraction of the cost”, said the scientist, who declined to be named due to the sensitivity of the issue.

Professor Zhou Yiguo, a radar technology researcher at the Chinese Academy of Sciences’ Institute of Electronics, said the distance between the moon and earth, 10 times further than the highest orbiting satellites, would cause enormous technological challenges.

“Either the radar has to be extremely powerful, or the antenna extremely large, otherwise it won’t be able to pick up the radio waves bouncing back from the earth,” he said.

“It is an important subject of research, but whether its advantage over satellite constellations can adjust the high cost and risk will need careful evaluation,” he added.

The lunar radar project comes as China shows signs of wanting to play a leading role in a renewed race to the moon, according to some space experts.

The design of a giant rocket the same size as the Saturn V in the US Apollo missions will be completed by 2020 to pave way for large scale activities in space including a “manned moon landing”, according to a scientific and technological innovation plan announced by the central government earlier this month.

China’s scientific authorities appear optimistic about the prospects for the lunar radar base, despite the concerns voiced by some experts.

Chai Yucheng, executive deputy president of the national science foundation, said at a meeting with the project team in April that the moon-based observational facility played a key role in China’s future scientific blueprint.

The government expects a “significant breakthrough” in the scheme by 2020 when the deadline comes for the team to submit its final report, Chai was quoted as saying on the Chinese Academy of Sciences website.

Quelle: South China Morning Post


1101 Views

Sonntag, 21. August 2016 - 16:45 Uhr

Raumfahrt - SpaceX stellt historisch geflogene Rakete auf Dauerausstellung aus

.

Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News

Crews outside the SpaceX’s headquarters in Southern California on Saturday positioned the booster that stuck the first Falcon 9 rocket landing for vertical display, and now the launcher is an unmistakable Space Age trophy visible to passersby on nearby streets and freeways.

Workers put the rocket near the southeast corner of SpaceX headquarters at the intersection of Crenshaw Blvd. and Jack Northrop Ave. in Hawthorne, California, a suburb of Los Angeles.

The 156-foot-tall (47-meter) rocket stage landed at Cape Canaveral after a Dec. 21 launch with 11 Orbcomm communications satellites.

It was the first launcher stage SpaceX recovered after years of effort, during which the company switched from a plan to retrieve rockets with parachutes to an outside-the-box scheme involving multiple engine restarts, landing legs, and precision landing algorithms.

The rocket stage unlatched from the Falcon 9’s second stage at an altitude of more than 250,000 feet (80 kilometers) about two-and-a-half minutes after liftoff from Cape Canaveral’s Complex 40 launch pad, then steered back to Florida’s Space Coast with the help of three rocket burns, culminating in a final maneuver to guide the booster with GPS navigation to a seaside landing target.

The touchdown marked the first time a rocket landed in such a manner after sending a satellite toward orbit. Burning leftover kerosene and liquid oxygen propellants, three of the rocket’s Merlin engines fired to reverse the first stage’s course, erasing the vehicle’s nearly 4,000 mph (6,000-kilometer per hour) downrange velocity as the booster continued to soar higher.

Then the rocket began a supersonic descent, and the trio of Merlin engines fired again for a re-entry burn. Finally, a single engine lit seconds before landing to slam on the brakes.

SpaceX chief executive Elon Musk declared shortly after the rocket landed that he planned to put it on display outside the company’s headquarters.

The placement of the booster upright required approval by the Federal Aviation Administration because SpaceX’s sprawling factory is located next to Hawthorne Municipal Airport.

Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News

After a thorough scrubbing to wash away soot residue from flying through its own exhaust, the rocket arrived in Hawthorne in June before going vertical in front of SpaceX’s main building Saturday with the help of two heavy-lifting cranes.

It joins SpaceX’s first Dragon capsule at the company’s headquarters. That spaceship, which flew into orbit in 2010, hangs inside the lobby.

Falcon 9 boosters recovered since the first one are being put to use as SpaceX strives to fly a previously-flown first stage on a satellite launch later this year. The second Falcon 9 launcher to return to Earth — landing April 8 on SpaceX’s drone ship in the Atlantic Ocean — is assigned to be the first rocket to fly a second time.

It would be the first time a space launcher’s first stage has been used twice, and would make the Falcon 9 only the second partially reusable launch vehicle in history, after the space shuttle.

SpaceX shipped another used rocket booster to its Central Texas facility for ground tests aimed at proving the Falcon 9’s first stage can survive multiple missions.

More photos of the Falcon 9 rocket going on display are posted below.

Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Credit: Gene Blevins/LA Daily News
Quelle: SN

1175 Views

Sonntag, 21. August 2016 - 14:15 Uhr

Astronomie - Wie kosmische Balletttänzer, drehen sich die Sterne der Plejaden

.

Pleiades cluster of stars
This image shows the Pleiades cluster of stars as seen through the eyes of WISE, or NASA's Wide-field Infrared Survey Explorer.
Credits: NASA/JPL-Caltech/UCLA

Like cosmic ballet dancers, the stars of the Pleiades cluster are spinning. But these celestial dancers are all twirling at different speeds. Astronomers have long wondered what determines the rotation rates of these stars.

 

By watching these stellar dancers, NASA's Kepler space telescope during its K2 mission has helped amass the most complete catalog of rotation periods for stars in a cluster. This information can help astronomers gain insight into where and how planets form around these stars, and how such stars evolve.    

 

"We hope that by comparing our results to other star clusters, we will learn more about the relationship between a star’s mass, its age, and even the history of its solar system," said Luisa Rebull, a research scientist at the Infrared Processing and Analysis Center at Caltech in Pasadena, California. She is the lead author of two new papers and a co-author on a third paper about these findings, all being published in the Astronomical Journal.

 

The Pleiades star cluster is one of the closest and most easily seen star clusters, residing just 445 light-years away from Earth, on average. At about 125 million years old, these stars -- known individually as Pleiads -- have reached stellar "young adulthood." In this stage of their lives, the stars are likely spinning the fastest they ever will.

 

As a typical star moves further along into adulthood, it loses some zip due to the copious emission of charged particles known as a stellar wind (in our solar system, we call this the solar wind). The charged particles are carried along the star’s magnetic fields, which overall exerts a braking effect on the rotation rate of the star.

 

Rebull and colleagues sought to delve deeper into these dynamics of stellar spin with Kepler. Given its field of view on the sky, Kepler observed approximately 1,000 stellar members of the Pleiades over the course of 72 days. The telescope measured the rotation rates of more than 750 stars in the Pleiades, including about 500 of the lowest-mass, tiniest, and dimmest cluster members, whose rotations could not previously be detected from ground-based instruments.

 

Kepler measurements of starlight infer the spin rate of a star by picking up small changes in its brightness. These changes result from "starspots" which, like the more-familiar sunspots on our sun, form when magnetic field concentrations prevent the normal release of energy at a star’s surface. The affected regions become cooler than their surroundings and appear dark in comparison.

 

As stars rotate, their starspots come in and out of Kepler’s view, offering a way to determine spin rate. Unlike the tiny, sunspot blemishes on our middle-aged sun, starspots can be gargantuan in stars as young as those in the Pleiades because stellar youth is associated with greater turbulence and magnetic activity. These starspots trigger larger brightness decreases, and make spin rate measurements easier to obtain.

 

During its observations of the Pleiades, a clear pattern emerged in the data: More massive stars tended to rotate slowly, while less massive stars tended to rotate rapidly. The big-and-slow stars' periods ranged from one to as many as 11 Earth-days. Many low-mass stars, however, took less than a day to complete a pirouette. (For comparison, our sedate sun revolves fully just once every 26 days.) The population of slow-rotating stars includes some ranging from a bit larger, hotter and more massive than our sun, down to other stars that are somewhat smaller, cooler and less massive. On the far end, the fast-rotating, fleet-footed, lowest-mass stars possess as little as a tenth of our sun’s mass. 

 

"In the 'ballet' of the Pleiades, we see that slow rotators tend to be more massive, whereas the fastest rotators tend to be very light stars," said Rebull.  

 

The main source of these differing spin rates is the internal structure of the stars, Rebull and colleagues suggest. Larger stars have a huge core enveloped in a thin layer of stellar material undergoing a process called convection, familiar to us from the circular motion of boiling water. Small stars, on the other hand, consist almost entirely of convective, roiling regions. As stars mature, the braking mechanism from magnetic fields more easily slows the spin rate of the thin, outermost layer of big stars than the comparatively thick, turbulent bulk of small stars.

 

Thanks to the Pleiades’ proximity, researchers think it should be possible to untangle the complex relationships between stars’ spin rates and other stellar properties. Those stellar properties, in turn, can influence the climates and habitability of a star’s hosted exoplanets. For instance, as spinning slows, so too does starspot generation, and the solar storms associated with starspots. Fewer solar storms means less intense, harmful radiation blasting into space and irradiating nearby planets and their potentially emerging biospheres.    

 

"The Pleiades star cluster provides an anchor for theoretical models of stellar rotation going both directions, younger and older," said Rebull. "We still have a lot we want to learn about how, when and why stars slow their spin rates and hang up their 'dance shoes,' so to speak."

 

Rebull and colleagues are now analyzing K2 mission data from an older star cluster, Praesepe, popularly known as the Beehive Cluster, to further explore this phenomenon in stellar structure and evolution.

 

"We’re really excited that K2 data of star clusters, such as the Pleiades, have provided astronomers with a bounty of new information and helped advance our knowledge of how stars rotate throughout their lives," said Steve Howell, project scientist for the K2 mission at NASA’s Ames Research Center in Moffett Field, California.

 

The K2 mission’s approach to studying stars employs the Kepler spacecraft's ability to precisely observe miniscule changes in starlight. Kepler’s primary mission ended in 2013, but more exoplanet and astrophysics observations continue with the K2 mission, which began in 2014.

 

Ames manages the Kepler and K2 missions for NASA's Science Mission Directorate. NASA's Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder.

Quelle: NASA


1133 Views

Sonntag, 21. August 2016 - 14:00 Uhr

Astronomie - Astronomen erlangen neue Einblicke in das Magnetfeld der Sonne

.

An artist's illustration depicts the interior of a low-mass star, such as GJ 3253.
An artist's illustration depicts the interior of a low-mass star, such as GJ 3253, a low-mass red dwarf star about 31 light years away from Earth, seen in an X-ray image from Chandra in the inset.
Credits: X-ray: NASA/CXC/Keele Univ./N. Wright et al; Optical: DSS

 

Researchers have discovered that four old red dwarf stars with masses less than half that of the Sun are emitting X-rays at a much lower rate than expected.

 

X-ray emission is an excellent indicator of a star’s magnetic field strength so this discovery suggests that these stars have much weaker magnetic fields than previously thought.

 

Since young stars of all masses have very high levels of X-ray emission and magnetic field strength, this suggests that the magnetic fields of these stars weakened over time. While this is a commonly observed property of stars like our Sun, it was not expected to occur for low-mass stars, as their internal structure is very different.

 

The Sun and other stars are giant spheres of superheated gas. The Sun's magnetic field is responsible for producing sunspots, its 11-year cycle, and powerful eruptions of particles from the solar surface. These solar storms can produce spectacular auroras on Earth, damage electrical power systems, knock out communications satellites, and affect astronauts in space.

 

“We have known for decades that the magnetic field on the Sun and other stars plays a huge role in how they behave, but many details remain mysterious,” said lead author Nicholas Wright of Keele University in the United Kingdom. “Our result is one step in the quest to fully understand the Sun and other stars.”

 

The rotation of a star and the flow of gas in its interior both play a role in producing its magnetic field. The rotation of the Sun and similar stars varies with latitude (the poles versus the equator) as well as in depth below the surface. Another factor in the generation of magnetic field is convection. Similar to the circulation of warm air inside an oven, the process of convection in a star distributes heat from the interior of the star to its surface in a circulating pattern of rising cells of hot gas and descending cooler gas.

 

Convection occurs in the outer third (by radius) of the Sun, while the hot gas closer to the core remains relatively still. There is a difference in the speed of rotation between these two regions. Many astronomers think this difference is responsible for generating most of the magnetic field in the Sun by causing magnetic fields along the border between the convection zone and the core to wind up and strengthen. Since stars rotate more slowly as they age, this also plays a role in how the magnetic field of such stars weakens with time

 

“In some ways you can think of the inside of a star as an incredibly complicated dance with many, many dancers,” said co-author Jeremy Drake of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “Some dancers move with each other while others move independently. This motion generates magnetic field, but how it works in detail is extremely challenging to determine.”

 

For stars much less massive than the Sun, convection occurs all the way into the core of the star. This means the boundary between regions with and without convection, thought to be crucial for generating magnetic field in the Sun, does not exist. One school of thought has been that magnetic field is generated mostly by convection in such stars. Since convection does not change as a star ages, their magnetic fields would not weaken much over time.

 

By studying four of these low-mass red dwarf stars in X-rays, Wright and Drake were able to test this hypothesis. They used NASA’s Chandra X-ray Observatory to study two of the stars and data from the ROSAT satellite to look at two others.

 

“We found that these smaller stars have magnetic fields that decrease as they age, exactly as it does in stars like our Sun,” said Wright. “This really goes against what we would have expected.”

 

These results imply that the interaction along the convection zone-core boundary does not dominate the generation of magnetic field in stars like our Sun, since the low mass stars studied by Wright and Drake lack such a region and yet their magnetic properties are very similar.

 

A paper describing these results by Wright and Drake appears in the July 28th issue of the journal Nature. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Quelle: NASA


1144 Views

Sonntag, 21. August 2016 - 09:00 Uhr

Raumfahrt - Kanadisches Unternehmen bewilligt 2. US-Patent für Space Elevator

.

7.08.2016

(Pembroke, Ont.) – Thoth Technology Inc. has secured further patent protection for their space elevator technology. The invention, published in this weeks United States Patent Gazette, describes an innovative new space elevator car mounting method.

“The spiral elevator mechanism allows bi-directional travel up and down a space tower,” its inventor Brendan Quine said. Thoth CEO Caroline Roberts describes the benefits of the new technology:

“Access to near space is set to revolutionise the way we do business on Earth. The advantages for energy generation, communications and space tourism are immense,” she said.

Thoth plans to construct pneumatic ThothX towers to access first 1.5 km and then 15 km above Earth within a decade.

US 9,403,607 available from USPTO here. Stay tuned for more space elevator news.

Contact us

For interview requests and additional information:

Alison King, Media Relations, (905) 484-3261 alison@thothx.com

Images

Image Credit: ThothX Space Elevator

ThothX_Elevator_Closeup3ThothX_Tower_Turbines1ThothX_Tower_Cars_Passing1ThothX_Pod_Closeup2ThothX_Tower_Distance0ThothX_Elevator_Closeup4

PREVIOUS THOTH NEWS

CANADIAN COMPANY GRANTED U.S. PATENT FOR SPACE ELEVATOR

July 21, 2015 (Toronto, Ont.) – Canadian space company, Thoth Technology Inc., has been granted the United States patent for a space elevator. Announced today in the USPTO’s Official Gazette, the freestanding space tower is pneumatically pressurized and actively-guided over its base. Reaching 20 km above the planet, it would stand more than 20 times the height of current tall structures and be used for wind-energy generation, communications and tourism.

The technology offers an exciting new way to access space using completely reusable hardware and saving more than 30% of the fuel of a conventional rocket.

“Astronauts would ascend to 20 km by electrical elevator. From the top of the tower, space planes will launch in a single stage to orbit, returning to the top of the tower for refueling and reflight,” said Dr. Brendan Quine, the inventor.

Thoth President and CEO, Caroline Roberts, believes the space tower, coupled with self-landing rocket technologies being developed by others, will herald a new era of space transportation.

“Landing on a barge at sea level is a great demonstration, but landing at 12 miles above sea level will make space flight more like taking a passenger jet.”

Contact us

For interview requests, high-res images and additional information:

Alison King

Media Relations

(905) 484-3261

alison@thothx.com

US Patent 9085897  “Space Elevator”:

http://www.uspto.gov/web/patents/patog/week29/OG/patent.html

Media Image caption: “20 km Space Tower/THOTHX.COM”

 
Quelle: THOT TECHNOLOGY
-
Update: 21.08.2016
.

Space elevator fans keep looking up, even when they’re stuck on the ground floor

Space elevator concept
An artist’s conception shows a space elevator rising up from Earth’s surface. (Credit: Pat Rawlings / NASA file)

 

Once upon a time, entrepreneurs were counting down to a date in 2018 when the first space elevator would open for business. NASA was setting aside millions of dollars to promote the technologies required for building that elevator. And space elevator fans were looking forward to a breakthrough that would drive the cost of space travel down to mere hundreds of dollars.

Today, the countdown is on indefinite hold. The NASA money is gone. And the dream of building the space elevator has been eclipsed by billionaire Elon Musk’s dream of putting colonists on Mars by the mid-2020s.

Nevertheless, the fans are still keeping the faith, and they’re backing up that faith with research studies. About 35 of them gathered today at Seattle’s Museum of Flight to kick off the 2016 Space Elevator Conference, presented by the International Space Elevator Consortium.

Some attendees came from as far away as Norway and Japan.

“The goal is not an unreal goal,” Hugh Cook, a space systems engineer from the Los Angeles area, told GeekWire during one of the breaks. “I think about the audacity of the transcontinental railroad. It was a crazy idea, but eventually the fire was lit, and it happened.”

The analogy is apt: Like the transcontinental railroad, the concept behind the space elevator goes back to the 19th century, to Russian scientist Konstantin Tsiolkovsky’s musings in 1895.

Space elevator diagram
This diagram shows one possible configuration for a space elevator. (Credit: Skyway / User:Booyabazooka via Wikimedia Commons)

The basic idea is that if you put a counterweight far enough from Earth, you could theoretically attach one end of a super-strong tether to the weight, and the other end to an anchor point on the planet. Then you could send people or payloads up and down that tether, as if they were riding a vertical railway to the sky.

Over the course of a century, engineers refined the concept and figured out that Earth’s counterweight would have to be placed about 62,000 miles (100,000 kilometers) above the planet’s surface. To handle the tension, the tether would have to be many times stronger than the strongest material available today.

Lots of details remain to be filled in, including exactly how the system would be built. But if it could be built, and if there were beam-powered rail cars capable of trundling up and down the tether, the cost of access to orbit would plummet. It would mark the beginning of a new space age.

To support technological development, NASA allocated prize money for a couple of challenges more than a decade ago. In 2009, Seattle-based LaserMotive won $900,000 of NASA’s money in a Power Beaming Challenge. As much as $2 million was set aside for a Strong Tether Challenge, but no one won a prize.

More recently, researchers have come up with reasons not to try building a space elevator. In June, Chinese researchers reported that a single defect in a tether made of super-strong carbon nanotubes could cause the tether to fail. Other studies have questioned how a space elevator would cope with bad weather, or space debris, or terrorists.

“A lot of people you know will tell you, forget about it,” said Bryan Laubscher, the founder of a carbon nanotube startup called Odysseus Technologies and director of the International Space Elevator Consortium.

But here’s what Pete Swan, the consortium’s president, will tell you: “Let’s gain some funding to do some really hard engineering work.”

 

If Swan came across a billionaire who wanted to provide the funding, he would recommend spending $1 million to $5 million per year over the course of three to five years. “That would pay dividends for the whole project,” Swan said.

Swan acknowledged that the technology isn’t yet ready to be put to the test, except in computer simulations. Studies suggest that it will take about 15 years for researchers to come up with suitably strong, sufficiently defect-free material for the tethers. It could be made of carbon nanotubes, diamond nanothreads or boron nitride nanotubes.

“That’s the only thing that we’re really waiting on,” Swan said.

Backers of the space elevator concept have done detailed studies on how much it would cost to build a space elevator once all the technological pieces are in place.

Swan said one concept would require about $15 billion, the second one would cost between $5 billion and $8 billion, and the ones after that could be built for $4 billion each. Another, more ambitious concept carries a price tag of $100 billion.

The consortium’s advisers and allies are working on further studies. For example,one recently published report delves into the logistics for a space elevator’s “Earth Port.”

An artist's conception shows the STARS-C mother and daughter satellite connected by a tether in orbit, (Credit: Kagawa University)
An artist’s conception shows the STARS-C mother and daughter satellite connected by a tether in orbit, (Credit: Kagawa University)

Meanwhile, Japan’s Kagawa University has been conducting a series of satellite experiments known as Project STARS (Space Tethered Autonomous Robotic Satellite). Two test satellites were launched in 2009 and 2014, and the third spacecraft – STARS-C – is due to be deployed from the International Space Station as early as this year.

Will the space elevator be built in 2035? Or will the timetable reflect a somewhat less precise prediction made 35 years ago by science-fiction master Arthur C. Clarke? “The space elevator will be built about 50 years after everyone stops laughing,” he wrote.

“I think people have stopped laughing,” Swan told GeekWire. “Just look at the crowd here. … The clock is running.”

The Space Elevator Conference will present the sixth annual Family Science Fest at the Museum of Flight from 10 a.m. to 3 p.m. Saturday. The event is included in the cost of museum admission, and features presentations on “Space Elevator 101” and “Space Elevator 201.” There’s also a youth robotics competition called RoboClimb, plus exhibits sponsored by science organizations and clubs.

For a deeper dive into the space elevator phenomenon, check out “Sky Line,” a feature-length documentary that’s available on DVD as well as streaming services such as VHXNetflix and Amazon Video.

Quelle: GeekWire


1603 Views

Samstag, 20. August 2016 - 20:30 Uhr

Astronomie - Besuch beim Sternenpark in der Rhön

.

Im Rahmen einer CENAP-VorOrt-Recherche war der Besuch im Sternenpark in der Rhön ein schöner Tagesausflug, welcher auf die Hohe Geba führte. Nachfolgende Aufnahmen sind im Juli 2016  auf der Hohe Geba entstanden, auf welcher ein schöner "Planeten-Weg"  angelegt wurde. Insbesondere fiel die schöne Gestaltung sowie der aktuelle Info-Stand zu den Planeten der Tafeln auf, daher können wir den Besuch auf der Hohe Geba für Astronomie-Begeisterte nur empfehlen, aber auch Spechteln dürfte da Oben eine Menge Freude machen.

-

2016-07-ajxha-hohe-geba

2016-07-ajxhb-hohe-geba

2016-07-ajxhc-hohe-geba

2016-07-ajxhd-hohe-geba

2016-07-ajxhe-hohe-geba

2016-07-ajxhf-hohe-geba

2016-07-ajxhg-hohe-geba

2016-07-ajxhh-hohe-geba

2016-07-ajxhi-hohe-geba

2016-07-ajxhj-hohe-geba

2016-07-ajxhk-hohe-geba

2016-07-ajxhn-hohe-geba

2016-07-ajxho-hohe-geba

2016-07-ajxhp-hohe-geba

2016-07-ajxic-hohe-geba

2016-07-ajxif-hohe-geba2016-07-ajxig-hohe-geba

Fotos: ©-hjkc


1197 Views

Samstag, 20. August 2016 - 17:30 Uhr

Raumfahrt - Funksignal der ESA-Station brauchte 80 Minuten bis zur Cassini-Sonde

.

MOST DISTANT CATCH FOR ESA STATION

cassini-crossing-rings-node-fu
Cassini during Grand Finale
-

An ESA tracking station has acquired signals from the international Cassini spacecraft orbiting Saturn, across more than 1.4 billion km of space.

Following a seven-year journey to Saturn, the NASA/ESA/ASI Cassini orbiter delivered Europe’s Huygens probe to the surface of Saturn’s mysterious moon Titan in January 2005, just a few months after becoming the first spacecraft to enter orbit around the giant gas planet.

Since then, Cassini and Huygens have returned a wealth of information on the Saturnian system to the global scientific community, helping us understand the massive planet, its multiple moons and its hauntingly beautiful system of rings.

Starting later this year, the mission will begin its final phase (see Cassini's Grand Finale) and ESA’s superbly sensitive deep-space tracking stations will be called in to help gather crucial radio science data.

The longest call

In an initial test on 10 August, ESA’s tracking station at New Norcia, Western Australia, hosting a 35 m-diameter, 630-tonne deep-space antenna, received signals transmitted by Cassini through 1.44 billion km of space.

ESA's New Norcia station (DSA-1) is designed to communicate with deep-space missions, typically at ranges in excess of 2 million km
New Norcia station

“This was the farthest-ever reception for an ESA station, and the radio signals – travelling at the speed of light – took 80 minutes to cover this vast distance,” says Daniel Firre, responsible for supporting Cassini radio science at ESOC, ESA’s operations centre in Darmstadt, Germany.

“We had to upgrade some software at ESOC, as we discovered that one file used for pointing the antenna did not have enough digits to encode the full distance to Cassini, but the test worked and demonstrated we can catch Cassini’s transmissions.”

Listening across the void

Some types of radio science observations use a ground station to detect signals transmitted from a spacecraft that have reflected off a planet or moon’s surface, or passed through the various layers of its atmosphere – or, in the case of Saturn, its rings.

Effects on the signals provide valuable information on the composition, state and structure of whatever they have passed through.

ESA's Estrack tracking station control room at ESOC, the European Space Operations Centre, Darmstadt
Tracking stations control room at ESOC

Numerous missions, including ESA’s Venus Express and Mars Express, have used this technique in the past. All three of ESA’s deep-space tracking stations (New Norcia in Australia, Cebreros in Spain and Malargüe in Argentina) were specifically designed to enable a radio science capability.

The Cassini mission has performed radio science observations many times during its time at Saturn. Previously, the mission relied solely on the antennas of NASA's Deep Space Network for these observations.

Now, the addition of ESA tracking capability will help provide the continuous radio contact needed during Cassini radio science activities. The data received by ESA will be delivered to NASA for subsequent scientific analysis.

Radio science during the Grand Finale

Starting in December and running into July 2017, Cassini will conduct a daring series of orbits in which the spacecraft will repeatedly climb high above Saturn’s poles, initially passing just outside its narrow F ring, and then later diving between the uppermost atmosphere and the innermost ring.

In 2016, NASA's Cassini mission will begin its final 'Grand Finale' and ESA’s superbly sensitive deep-space tracking stations will be called in to help gather crucial radio science data.
Grand Finale orbits

When Cassini plunges past Saturn, an ESA station will listen, recording radio signals that will be relayed to NASA.

These data will provide detailed maps of Saturn’s gravity, revealing the planet’s inner composition and possibly helping solve the mystery of just how fast the interior is rotating. They will also help scientists study the rings.

Until December, a half-dozen more test passes using ESA’s New Norcia and Malargüe stations to receive Cassini signals are planned, after which the two will be used during some two-dozen Grand Finale orbits.

Inter-agency cooperation is a key element

The support is particularly challenging, as listening passes can last up to 30 hours, during which reception will be handed over multiple times between the two ESA stations and NASA’s Canberra deep-space communication complex in Australia; NASA’s Madrid complex will also take part.

“We need uninterrupted signal reception to optimise the Cassini radio science data, so the ESA and NASA stations really have to work in close coordination for recording and handover,” says Manfred Lugert, responsible for ESA’s Estrack ground station network.

Due to geometry, the two ESA stations – located in the southern hemisphere – are ideally able to support Cassini radio science. Northern/southern hemispheric coverage was one factor taken into account when ESA built its station in Argentina in 2012.

“We are really pleased that we can work closely with our NASA colleagues and contribute to Cassini’s incredibly valuable radio science goals,” says Manfred, adding: “It’s an impressive display of what two agencies working together can achieve.”

Quelle: ESA


1366 Views

Samstag, 20. August 2016 - 17:15 Uhr

Raumfahrt - ESA Studie: CubeSats / Nanosatelliten aneinander andocken

.

HOW TO DOCK CUBESATS

Docking CubeSats
.

The miniature satellites known as CubeSats already play a variety of roles in space. In future they could also serve as the building blocks of other, larger missions by being docked together in orbit.

CubeSats are nanosatellites of standardised dimensions based on multiple 10-cm-sided cubes, which ESA is employing for both educational and technology-demonstration purposes.

“The ability to autonomously rendezvous and dock CubeSats could enable in-orbit assembly of larger structures that simply would not be possible in any other way,” explains Roger Walker, overseeing ESA’s technology CubeSats.

”Think for instance of constructing a very large telescope mirror or radio antenna for astronomy out of separate CubeSat segments, getting around size limitations set by our rocket fairings.”

Lining up for CubeSat docking

So as a first step, ESA is part-funding PhD research into autonomous CubeSat docking techniques.

“We’re looking at the level of guidance, navigation and control performance that would be achievable with the miniaturised sensors and propulsion available to such small satellites, and what kind of docking accuracy might be possible,” said Finn Ankersen, an ESA expert in rendezvous and docking and co-supervisor of the research.

Researcher Camille Pirat of École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland is having his PhD work supported through ESA’s Networking and Partnering Initiative, intended to harness advanced academic research for space applications.

 

“My interest in the topic came out of a previous R&D project with ESA, designing a CubeSat mission to test out active space debris removal technologies, such as those that will be needed for ESA’s proposed e.Deorbit mission, to capture and deorbit an entire large derelict satellite from orbit.

“The idea would be to demonstrate the pre-capture approach and synchronising of attitude between the chaser spacecraft and the tumbling target at the CubeSat scale, to prepare for a full-scale mission. It was that work that gave rise to this very interesting question: how can we perform rendezvous and docking between CubeSats?

“The challenge is that CubeSats obviously have tight mass, propellant and power constraints. We will need a positioning accuracy of something like 1 cm, previously achieved by ESA’s ATV supply spacecraft when docking with the International Space Station, but obviously the ATV was orders of magnitude bigger. 

ESA's ATV-5 cargo vessel at moment of docking on 12 August 2014.
ATV docking with ISS

“A CubeSat docking would be more like placing a needle into a 1-cm-diameter hole, employing a limited number of sensors and of course a strictly limited amount of propellant. A high level of onboard autonomy would also be desirable.”

The two nanosatellites would begin by using GPS navigation for the control system to bring them into closer range, with inter-satellite links established at about 20 km from each other.

“Closer in, we’d be relying on camera-based navigation, with LED beacons fitted to the CubeSats to help measure the relative range and attitude between chaser and target. What I’m currently looking at is how changes in lighting conditions might impact this solution – if sunglare would be a problem, for example.”

ESA CubeSats in flight

Cold-gas thrusters are currently being baselined, although electric propulsion would offer a way of squeezing extra efficiency out of scarce onboard fuel for longer-range rendezvous operations – with knock-on effects for the size and capacity of solar arrays.

“I’m doing the work in Switzerland, but with regular visits to ESA’s ESTEC technical centre in the Netherlands,” adds Camille Pirat. “This gives me the chance to confer with Roger and also veterans of ESA’s ATV spacecraft such as Finn – it was such a great programme, it’s very useful to be able to learn from their experience.”

Quelle: ESA


1116 Views

Samstag, 20. August 2016 - 16:45 Uhr

Astronomie - Hubble untersucht Sternen Schrapnells

.

hubble-friday-08192016

Several thousand years ago, a star some 160,000 light-years away from us exploded, scattering stellar shrapnel across the sky. The aftermath of this energetic detonation is shown here in this striking image from the NASA/ESA Hubble Space Telescope’s Wide Field Camera 3.

 

The exploding star was a white dwarf located in the Large Magellanic Cloud, one of our nearest neighboring galaxies. Around 97 percent of stars within the Milky Way that are between a tenth and eight times the mass of the sun are expected to end up as white dwarfs. These stars can face a number of different fates, one of which is to explode as supernovae, some of the brightest events ever observed in the universe. If a white dwarf is part of a binary star system, it can siphon material from a close companion. After gobbling up more than it can handle — and swelling to approximately one and a half times the size of the sun — the star becomes unstable and ignites as a Type Ia supernova.

 

This was the case for the supernova remnant pictured here, which is known as DEM L71. It formed when a white dwarf reached the end of its life and ripped itself apart, ejecting a superheated cloud of debris in the process. Slamming into the surrounding interstellar gas, this stellar shrapnel gradually diffused into the separate fiery filaments of material seen scattered across this skyscape.

Quelle: NASA

 

 

 


1145 Views

Samstag, 20. August 2016 - 16:30 Uhr

Mars-Chronike - Studenten fliegen Prototyp von potenziellen Mars Flugzeug

.

Students Fly Prototype of Potential Mars Airplane

Derek Abramson, from left, Justin Hall, and Alexander Frock position the Prandtl-M glider
Derek Abramson, from left, Justin Hall, and Alexander Flock position the Prandtl-M glider aircraft onto the Carbon Cub that drops it from 500 feet altitude.
Credits: NASA Photo / Lauren Hughes

Some interns get coffee. Others might make copies. Not at NASA Armstrong Flight Research Center in California, where a group of students successfully flew a prototype of an aircraft that could one day fly in the Martian atmosphere and send its findings back to Earth.

 

Called the Preliminary Research Aerodynamic Design to Land on Mars, or Prandtl-M, the small, remotely piloted glider aircraft flew Aug. 11 at Armstrong. It continues an effort that began last year with a mostly different group of students.

 

“The first successful flights felt like a huge relief,” said John Bodylski, a mechanical engineering student at Irvine Valley College in California. “While we still plan to perfect the design, it is a pretty exciting feeling to realize that the aircraft is working. At first I didn't believe it and had to rewatch the footage from the flight.”

 

Bodylski is participating in a NASA student program aimed at developing skills learned at school and applying those abilities to a research challenge. The NASA Flight Scholars activity, which focuses on giving community college students an early opportunity to perform research, and the Education Unmanned Aerial Systems activity, which provides college students an opportunity to work on NASA UAS projects, are key components of the Prandtl-M team.

 

Jonathan Adams, from left, John Bodylski, Justin Hall, Caitlin Kennedy and Dave Berger watch a computer screen.
Jonathan Adams, from left, John Bodylski, Justin Hall, Caitlin Kennedy and Dave Berger watch a computer screen providing the Prandtl-M’s exact location and altitude.
Credits: NASA Photo / Kyria Luxon

Bodylski worked on how to track the Prandtl-M last summer from Irvine, but this year he was accepted to come to Armstrong with the added responsibility of onboard avionics.

 

“Being at Armstrong this year has allowed for me to take advantage of the engineering knowledge and fabrication abilities of the center,” he added. “Work at Armstrong is faster paced than working from a school and allows for designs to be created and tested in a more rapid fashion.”

 

Those are some of the concepts of the program, said Dave Berger, a key driver and manager of the two Education activities.

 

“What we like about small prototypes and this student program is this is real research, real cutting edge technology development,” he explained. “They can work on all the major areas of aerospace engineering, such as controls, aerodynamics, structures and instrumentation encapsulated in one project. The program is small enough that we can design and fabricate very fast and we can try something that no one has ever done before. It might not be successful the first time, or the second time.”

 

Emerson Baker, Alexander Flock and Ryan Dibley retrieve the Prandtl-M after a successful test flight.
Emerson Baker, Alexander Flock and Ryan Dibley retrieve the Prandtl-M after a successful test flight.
Credits: NASA Photo / Lauren Hughes

Inspiring and exciting students, while developing a talent pool for NASA and the aerospace industry, are key to science, technology, engineering and mathematics (STEM) education that is a goal of the agency.

 

“Students can see the path to a technical, or engineering career path,” Berger added.

 

That was the case with the Prandtl-M. It was through repeated challenge and learning that the successful aircraft flew.

 

Caitlin Kennedy, an undergraduate intern studying physics and astronomy from the University of Wyoming, said the Prandtl-M work has been a one-of-a-kind experience.

 

“When I came here I had no idea what operations engineers did,” Kennedy said. “I absolutely love it because I had an overview and I was involved in every step of the project. It takes a while to get ready for a flight and we learn something from every flight.”

 

As an example, she explained how rooftop flights of six or seven Prandtl-M vehicle shapes where tested to determine which shape would be dropped from a Carbon Cub aircraft. Once a shape was decided, servos were added to control the ailerons.

 

Emerson Baker and Caitlyn Kennedy check out the Prandtl-M before a test flight.
Emerson Baker and Caitlin Kennedy check out the Prandtl-M before a test flight.
Credits: NASA Photo / Lauren Hughes

For Emerson Baker, who is studying aerospace engineering at California State Polytechnic University in California, the processes of manufacturing a carbon-fiber prototype vehicle and learning about the failures and success of a flight project were exciting.

 

“They went through the whole process of manufacturing a carbon fiber vehicle and a lot of the R/C (remote control) aircraft testing. Prandtl-M had a number of rough flights before this one. There are so many positive people working on the project that when something didn’t go well, we would laugh about it and try something new that now is working.”

 

Some students have had their career paths altered by the program already.

 

“I was planning to be a teacher and changed my mind once I had an internship here and found out how fun engineering could be,” said Kirsten Fogg, who was an intern and now is an Armstrong operations engineer. “I am also currently in a master’s program for engineering.”

 

The designs began last summer with students flying designs down the halls at the NASA center to more involved carbon fiber molds. Before the successful test flight, the student crew and their mentors devised a steel construction launcher and tested six different flight vehicle shapes to determine which worked best and use the design for the next flight vehicle.

 

“We could give them the answers, but we give them the room to make their own discoveries and their own mistakes,” said Robert “Red” Jensen, who is the Small Unmanned Aircraft Systems chief pilot and master technician for the Dale Reed Subscale Flight Research Lab.

 

 Prandtl-M, flies during a test flight.
The Preliminary Research Aerodynamic Design to Land on Mars, or Prandtl-M, flies during a test flight. Students during the past two summers worked on the concept leading to successful flights.
Credits: NASA Photo / Lauren Hughes

In addition to developing a Prandtl-M testbed aircraft, groups of students also worked on guidance and navigation autonomous systems and sensors, said Al Bowers, NASA Armstrong chief scientist and Prandtl-m program manager.

 

The next steps will be to continue development and integration of the airframe and autonomous systems and meeting the challenges that happen when such systems are incorporated, he added.

 

With hard work and perseverance, the students believe the Prandtl-M and its systems they helped develop and validate will one day fly the skies of Mars.

Quelle: NASA
NASA Armstrong Flight Research Center


1190 Views


Weitere 10 Nachrichten nachladen...