b]GREENBELT, MARYLAND[/b]—For months, inside the towering Building 29 here at Goddard Space Flight Center, the four scientific instruments at the heart of the James Webb Space Telescope (JWST, or Webb) have been sealed in what looks like a house-sized pressure cooker. A rhythmic chirp-chirp-chirp sounds as vacuum pumps keep the interior at a spacelike ten-billionth of an atmosphere while helium cools it to –250°C. Inside, the instruments, bolted to the framework that will hold them in space, are bathed in infrared light—focused and diffuse, in laserlike needles and uniform beams—to test their response.
The pressure cooker is an apt metaphor for the whole project. Webb is the biggest, most complex, and most expensive science mission that NASA has ever attempted, and expectations among astronomers and the public are huge. Webb will have 100 times the sensitivity of the Hubble Space Telescope. It will be able to look into the universe’s infancy, when the very first galaxies were forming; study the birth of stars and their planetary systems; and analyze the atmospheres of exoplanets, perhaps even detecting signs of life. “If you put something this powerful into space, who knows what we can find? It’s going to be revolutionary because it’s so powerful,” says Matt Mountain, director of the Association of Universities for Research in Astronomy in Washington, D.C., and former JWST telescope scientist. Like that of Hubble, however, Webb’s construction has been plagued by redesigns, schedule slips, and cost overruns that have strained relationships with contractors, partners in Canada and Europe, and—most crucially—supporters in the U.S. Congress. Other missions had to be slowed or put on ice as Webb consumed available resources. A crisis in 2010 and 2011 almost saw it canceled, although lately the project has largely kept within its schedule and budget, now about $8 billion.
But plenty could go wrong between now and the moment in late 2018 when the telescope begins sending back data from its vantage point 1.5 million kilometers from Earth. It faces the stresses of launch, the intricate unfurling of its mirror and sunshield after it emerges from its chrysalis-like launch fairing, and the possibility of failure in its many cutting-edge technologies. Unlike Hubble, saved by a space shuttle mission that repaired its faulty optics, it is too far from Earth to fix. And not just the future of space-based astronomy, but also NASA’s ability to build complex science missions, depends on its success.
That’s why those instruments sat in Goddard’s pressure cooker for what is known as cryo-vacuum test 3 (CV3). And it is why Webb’s other components—including the mirror and telescope structure, the “bus” that will supply power and control the telescope, and the tennis court–sized, multilayer parasol that will help keep it cool—must undergo a gauntlet of testing, alone and in combinations, until the whole spacecraft is ready. For those on the inside, the strain will only increase as assembly continues, the tests get bigger and more comprehensive, and the spacecraft is launched into space. Only when Webb opens its eye and successfully focuses on its first star will the strain be released.
In the mid-1990s, after Hubble had had its optics corrected and was busy revolutionizing astronomy, researchers began planning its successor. The catch phrase in NASA at the time, championed by agency chief Daniel Goldin, was “faster, better, cheaper.” Goldin challenged NASA engineers and the astronomical community to come up with a follow-on that was cheaper than Hubble but bigger, with a mirror 8 meters across. He received a standing ovation when he described the plans to the American Astronomical Society in 1996. Whereas Hubble covered the whole range of visible light, plus a smidgen of ultraviolet and infrared, the Next Generation Space Telescope (as it was then known) would be a dedicated infrared observatory.
If you put something this powerful into space, who knows what we can find? It’s going to be revolutionary because it’s so powerful.
Matt Mountain, director of the Association of Universities for Research in Astronomy, and former JWST telescope scientist
For astronomers, the infrared spectrum was a beckoning frontier. Visible light from the most distant objects in the universe, the very first stars and galaxies that formed after the big bang, gets stretched so much by the expansion of the universe that it ends up in the infrared range by the time it reaches us. Many chemical signatures in exoplanet atmospheres also show themselves in the infrared region. Yet Earth’s atmosphere blocks most infrared. Webb will give us “the first high-definition view of the midinfrared universe,” says Matt Greenhouse, JWST project scientist for the instrument payload at Goddard.
To capture that light, however, NASA engineers had to overcome huge challenges. The first was heat: To keep the infrared glow of the telescope itself from swamping faint astronomical signals, Webb would need to operate at about –233°C, 40° above absolute zero (40 K). That would require entirely new instrument designs. Size and weight constraints posed additional hurdles: An 8-meter mirror would never fit inside a rocket fairing, so it would have to fold up for launch. The sunshield, too, would have to be collapsible and made of a superthin, lightweight membrane. And the telescope structure would have to be absolutely rigid but lightweight enough to limit the weight of the whole orbiting observatory to no more than 6 tonnes, just a few percent of the weight of a similar-size ground-based telescope. “We knew we would have to invent 10 new technologies” to make the telescope work, says NASA’s JWST Program Director Eric Smith, in Washington, D.C.
Take the mirror. Hubble’s was made from a single slab of glass, but Webb’s folding mirror would need to be segmented, made up of separate hexagonal pieces—a design used in many top ground-based instruments, including the Keck telescopes in Hawaii. The segments would have to be minutely controlled to meld them into a single optical surface, with their reflected light completely in step—a process known as phasing. In Webb, each hexagonal segment will sit on six actuators that control its orientation, plus one in the center to adjust its curvature.
Now too large to fit inside a plane, Webb will make its final prelaunch journey by ship, down the California coast and through the Panama Canal to French Guiana—home of Europe’s spaceport, and a waiting Ariane 5 launcher, part of Europe’s contribution to the project. In October 2018, the Ariane will fling Webb toward L2, a gravitational balance point 1.5 million kilometers from Earth, directly away from the sun. The journey will take 29 days.
Тhe world's fastest self-driving cars AUDI RS goes to the market ... by "themselves"
Two Audi RS7 performance sedans raced around a track in northern Germany. The car without a driver won this matchup by five seconds.
In its effort to bring autonomous-driving technology to the streets, Volkswagen AG’s Audi is testing unmanned vehicles at speeds as fast as 305 km/h. In these experiments, the car decides for itself the best way to take the corners in its race against human drivers.
The map the car gets “just contains the left and right boundaries of the track,” Peter Bergmiller, an Audi technician, said Tuesday during a test on a track in Oschersleben (193 kilometres west of Berlin) with a vehicle named Bobby. “The car starts to think about it and generates its optimal line.”
Auto makers from Mercedes-Benz to Tesla Motors Inc. are developing systems to ease the strain of driving by letting cars park themselves and even take over the wheel in stop-and-go traffic. By showing that computers are able to push cars to their limits on race tracks, Audi is aiming to convince regulators that the technology can be safe in the real world.
If authorities open the door to self-driving features, “the first systems for piloted driving could come to market in a few years,” Audi development chief Ulrich Hackenberg said in a presentation of the brand’s autonomous-driving technology.
There’s a lot at stake in getting cars equipped with these features on the road. Technology for self-driving cars is forecast to become an $87 billion market by 2030, according to Boston-based Lux Research.
Green Line - The Third Line of Sofia Subway is put into service. 550 000 passengers use the Sofia underground railway at 2018
The 16 km long third line is planned to connect Ovcha Kupel neighbourhood (in southwest Sofia) and Vasil Levski neighbourhood (in northeast Sofia), with 19 stations in total, including two transfer stations in the city centre, with both of the already operational lines. According to the Municipality, they estimate the line will be put into service by 2018.
There will be 8 overground and 11 underground stations. The project design contract was awarded to the Czech company Metroprojekt Praha a.s.
In March 2014, a tender for construction of the central section of the line was announced. The section is 7 km long and includes 7 stations, two of them transfer to lines 1 and 2. With the announcement of the tender it became clear, that the initial plans for 19 stations had been partly amended and 2 of the stations will be not be built, one at Doyran boulevard and another at Shipka street. The tunnel of the central section shall be excavated by a TBM, while the construction of stations shall be awarded to other companies. The construction of the section shall be completed within 45 months.In January 2015, a tender for 20 trains, that shall serve the central section of the line, was announced. Driverless train operation, with Grade of Automation 3 (GoA 3), and platform screen doors will ensure the safety of the passengers.
The Sofia subway will be used by 550 000 passengers in 2018, according to Stoyan Bratoev, Executive Director of municipality-owned company Metropoliten EAD.
In a Sunday interview for the Focus news agency, he said that the Sofia subway was being used by 80 000 a 300 000 passengers and their number was to reach 550 000 with the completion of the main part of the third subway line.
He said that the subway stations on the route to Sofia Business Park in the Mladost residential district and to Sofia Airport were being built, adding that their launch in 2014 was expected to boost the number of passengers by around 90 000 to a total of 380 000.
Bratoev noted that the third subway line was to bring 170 000 new passengers in 2018, provided that it was built in its entirety, or 110 000 extra passengers, provided that only the central part was built. …
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Photo of the year: First Detailed image of a Black Hole - Milky way's core
A supermassive black hole lurks at the center of our galaxy, but we’ve never seen it. We know it’s there, and that it has the mass of about 4 million suns, and that the stars in our galaxy revolve around it. But no one could tell you exactly what it looks like.
In fact, astronomers have never been able to snap a direct image of any black hole, ever. That’s because although the black holes at the center of galaxies are supermassive, they’re really far away. It’s akin to trying see a grapefruit, DVD, or bagel on the surface of the moon. You’d need a supermassive telescope, 1000 times the size of Hubble, to spot one.
Or, maybe, just eight telescopes working together. The Event Horizon Telescope (EHT), which is actually a network of eight radiofrequency observatories around the world, switched on for the first time on April 5. Between now and April 14, the observatories hope to gather enough data to piece together our first snapshot a black hole’s event horizon—the “point of no return” threshold after which nothing can escape the black hole’s gravity.
These telescopes will collect radio waves emitting from the supermassive black hole at the center of the Milky Way, as well as the neighboring galaxy Messier 87, and stitch them together into visual images. The EHT’s resolution is said to be about as good as being able to count the stitches on a baseball from 8,000 miles away.
Over at Nature, Davide Castelvecchi explains that instead of using just one very big mirror or antenna dish, the technique (called very-long-baseline interferometry) works by merging multiple observatories into “one virtual telescope—with an effective aperture as big as the distance between them.”
Heino Falcke, an astrophysicist at Radboud University in the Netherlands, told Popular Science that this project wouldn’t have been possible just a few years ago. The Atacama Large Millimeter Array, which has been fully operational since 2013, “adds a lot of sensitivity and image quality,” he says. “Also, we need to record and store an enormous amount of data—almost half a petabyte per telescope. That wasn’t feasible a few years ago.”
EHT’s goal isn’t just to see what our friendly neighborhood black hole is up to. The team, lead by astrophysicist Sheperd Doeleman at Harvard University, thinks that “seeing” a black hole for the first time could help lead to a theory of everything, uniting the laws that govern very small quantum mechanical physics with the laws that govern very big things in the universe.
The project also aims to learn more about how these gravitational anomalies pull in matter, and how they generate huge jets of plasma. It could also shed light on Stephen Hawking’s hypothesis that information that falls into a black hole must somehow leak back out.
After analyzing the vast amounts of data that will be generated by this experiment—about 2 petabytes for each of the four or five nights of observation—the EHT team hopes to have a picture ready in 2018.