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Posted: 26 Feb 2015 03:00 AM PST
The MUSE instrument on ESO’s Very Large Telescope has given astronomers the best ever three-dimensional view of the deep Universe. After staring at the Hubble Deep Field South region for only 27 hours, the new observations reveal the distances, motions and other properties of far more galaxies than ever before in this tiny piece of the sky. They also go beyond Hubble and reveal previously invisible objects. By taking very long exposure pictures of regions of the sky, astronomers have created many deep fields that have revealed much about the early Universe. The most famous of these was the original Hubble Deep Field, taken by the NASA/ESA Hubble Space Telescope over several days in late 1995. This spectacular and iconic picture rapidly transformed our understanding of the content of the Universe when it was young. It was followed two years later by a similar view in the southern sky — the Hubble Deep Field South.
But these images did not hold all the answers — to find out more about the galaxies in the deep field images, astronomers had to carefully look at each one with other instruments, a difficult and time-consuming job. But now, for the first time, the new MUSE instrument can do both jobs at once — and far more quickly.
One of the first observations using MUSE after it was commissioned on the VLT in 2014 was a long hard look at the Hubble Deep Field South (HDF-S). The results exceeded expectations.
“After just a few hours of observations at the telescope, we had a quick look at the data and found many galaxies — it was very encouraging. And when we got back to Europe we started exploring the data in more detail. It was like fishing in deep water and each new catch generated a lot of excitement and discussion of the species we were finding,” explained Roland Bacon (Centre de Recherche Astrophysique de Lyon, France, CNRS) principal investigator of the MUSE instrument and leader of the commissioning team.
For every part of the MUSE view of HDF-S there is not just a pixel in an image, but also a spectrum revealing the intensity of the light’s different component colours at that point — about 90 000 spectra in total. Each spectrum covers a range of wavelengths from the blue part of the spectrum into the near-infrared (475‒930 nanometres). These can reveal the distance, composition and internal motions of hundreds of distant galaxies — as well as catching a small number of very faint stars in the Milky Way.
Even though the total exposure time was much shorter than for the Hubble images, the HDF-S MUSE data revealed more than twenty very faint objects in this small patch of the sky that Hubble did not record at all. MUSE is particularly sensitive to objects that emit most of their energy at a few particular wavelengths as these show up as bright spots in the data. Galaxies in the early Universe typically have such spectra, as they contain hydrogen gas glowing under the ultraviolet radiation from hot young stars.
“The greatest excitement came when we found very distant galaxies that were not even visible in the deepest Hubble image. After so many years of hard work on the instrument, it was a powerful experience for me to see our dreams becoming reality,” adds Roland Bacon.
By looking carefully at all the spectra in the MUSE observations of the HDF-S, the team measured the distances to 189 galaxies. They ranged from some that were relatively close, right out to some that were seen when the Universe was less than one billion years old. This is more than ten times the number of measurements of distance than had existed before for this area of sky.
For the closer galaxies, MUSE can do far more and look at the different properties of different parts of the same galaxy. This reveals how the galaxy is rotating and how other properties vary from place to place. This is a powerful way of understanding how galaxies evolve through cosmic time.
“Now that we have demonstrated MUSE’s unique capabilities for exploring the deep Universe, we are going to look at other deep fields, such as the Hubble Ultra Deep field. We will be able to study thousands of galaxies and to discover new extremely faint and distant galaxies. These small infant galaxies, seen as they were more than 10 billion years in the past, gradually grew up to become galaxies like the Milky Way that we see today,” concludes Roland Bacon.
The research was presented in a paper entitled “The MUSE 3D view of the Hubble Deep Field South” by R. Bacon et al., to appear in the journal Astronomy & Astrophysics on 26 February 2015.
Credit: ESO
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Posted: 25 Feb 2015 03:03 PM PST
NASA astronauts Barry "Butch" Wilmore and Terry Virts floated back outside the International Space Station Wednesday for the second of three spacewalks to help ready the lab complex for dockings by commercial crew capsules being built by Boeing and SpaceX. Floating in the Quest airlock module, Wilmore and Virts switched their spacesuits to battery power at 6:51 a.m. EST to officially kick off a planned six-and-a-half-hour spacewalk, the second of three outings planned by the Expedition 42 crew. They ended their spacewalk at 1:34 p.m. EST with the repressurization of the Quest airlock. Back inside the station's airlock, Virts reported a small amount of water in his space helmet, but officials said he was not in any danger.
Wilmore and Virts completed all the scheduled tasks for today. They completed rigging a series of power cables on Pressurized Mating Adapter-2, lubricated the Latching End Effecter of the space station’s Canadarm2 robotic arm, and prepared the Tranquility module for the station’s upcoming reconfiguration in preparation for the arrival of commercial crew vehicles later this decade. They also were able to complete get-ahead work for the installation during Sunday’s spacewalk of the Common Communications for Visiting Vehicles (C2V2) system by pre-staging wire-ties that will be used to secure some 400 feet of cable.
Virts reported seeing a small amount of water floating free in his helmet during airlock repressurization at the conclusion of Wednesday’s spacewalk. There was no report of water during the spacewalk itself, and the crew was never in any danger. After removing the helmet, Expedition 42 crew member Samantha Cristoforetti reported on the free floating water inside the helmet and indicated the helmet absorption pad was damp. Ground teams are currently analyzing the situation to confirm the source of the water.
"Terry was saying he's got some water in his helmet, he just noticed it a minute ago," European Space Agency (ESA) astronaut Cristoforetti told flight controllers in Houston. "It's about 3 inches in diameter, it's kind of pooling on the front side of the helmet above his eye level, and he does feel a little bit of squishiness in the back of the HAP (helmet absorption pad)."
Virts was wearing spacesuit #3005, which experienced a similar issue after a spacewalk in December 2013.
"At first, I saw just a little bit of water pooled in my helmet and it seemed normal because I was face down and that's where water pools," Virts said. "Except for when there's no gravity, so that's not normal."
On July 16, 2013, ESA astronaut Luca Parmitano's helmet flooded with water during a spacewalk. He made it back to the safety of the station's airlock in the nick of time, assisted by fellow spacewalker Christopher Cassidy - but the event easily could have turned fatal.
The 6-hour, 43-minute spacewalk was the third for Wilmore and the second for Virts. Wilmore now has spent 19 hours and 58 minutes in the void of space during his three spacewalks. Virts has now spent 13 hours and 24 minutes outside during his two excursions. Crews have now spent a total of 1,165 hours and 51 minutes conducting space station assembly and maintenance during 186 spacewalks.
The duo will venture outside the space station again on Sunday, March 1, to install the C2V2 equipment commercial spacecraft delivering crews to the space station will use to rendezvous and dock with the orbital laboratory. NASA TV coverage will begin at 6 a.m. Sunday ahead of a planned 7:10 a.m. start time for the spacewalk.
At least four additional spacewalks are planned later this year to complete the most extensive space station reconfiguration since the end of the shuttle era in 2011. Nearly 900 hours of crew time will be required for the spacewalks, robotic activity and work inside the station to ready the lab for arrivals and departures of commercial crew capsules.
Credit: NASA, cbsnews.com
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Posted: 25 Feb 2015 02:21 PM PST
Dwarf planet Ceres continues to puzzle scientists as NASA's Dawn spacecraft gets closer to being captured into orbit around the object. The latest images from Dawn, taken nearly 29,000 miles (46,000 kilometers) from Ceres, reveal that a bright spot that stands out in previous images lies close to yet another bright area. "Ceres' bright spot can now be seen to have a companion of lesser brightness, but apparently in the same basin. This may be pointing to a volcano-like origin of the spots, but we will have to wait for better resolution before we can make such geologic interpretations," said Chris Russell, principal investigator for the Dawn mission, based at the University of California, Los Angeles.
Using its ion propulsion system, Dawn will enter orbit around Ceres on March 6. As scientists receive better and better views of the dwarf planet over the next 16 months, they hope to gain a deeper understanding of its origin and evolution by studying its surface. The intriguing bright spots and other interesting features of this captivating world will come into sharper focus.
"The brightest spot continues to be too small to resolve with our camera, but despite its size it is brighter than anything else on Ceres. This is truly unexpected and still a mystery to us," said Andreas Nathues, lead investigator for the framing camera team at the Max Planck Institute for Solar System Research (MPS), Gottingen, Germany.
The surface inside the crater appears very smooth and disrupted by only few smaller craters. "This suggests that the large crater is the remnant of a comparatively young impact," explained Michael Schäfer, Dawn scientist at the MPS.
"During the course of the mission, the craters will enable us to take an indirect look into Ceres' interior“, said Nathues.
"The way the impactors deform the dwarf planet's subsurface and the way the subsurface reacts to this on long time scales allows conclusions about the material hidden beneath the topmost layer," Schäfer added. In the coming weeks and months, the researchers therefore intend to precisely survey Ceres' surface structures.
Dawn visited the giant asteroid Vesta from 2011 to 2012, delivering more than 30,000 images of the body along with many other measurements, and providing insights about its composition and geological history. Vesta has an average diameter of 326 miles (525 kilometers), while Ceres has an average diameter of 590 miles (950 kilometers). Vesta and Ceres are the two most massive bodies in the asteroid belt, located between Mars and Jupiter.
Dawn's mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK, Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, the Max Planck Institute for Solar System Research, the Italian Space Agency and the Italian National Astrophysical Institute are international partners on the mission team.
Credit: NASA, mps.mpg.de
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Posted: 25 Feb 2015 01:45 PM PST
Russia will continue using the International Space Station (ISS) until around 2024 and is planning to build its own orbital outpost using the existing ISS modules, Federal Space Agency Roscosmos said Tuesday. "The configuration of a multi-purpose lab module, a docking module and a scientific-energy module allows us to build an orbital station to ensure Russia's access to outer space," Roscosmos Science and Technology Board said in a statement. In addition, Russia will actively study the Moon using robotic equipment in the next decade with the goal of sending manned missions to the Earth's satellite around 2030, the board said.
“Piloting cosmonauts is part of our general space strategy and today with have decided upon our main trajectory,” said Yury Koptev, a representative of the Science and Technology board, Tass reported. “This is through the International Space Station and working towards a lunar program in the Earth’s orbit and in deep space.”
The Science and Technology Board will convene again in March to discuss the development of space vehicles that will be used to put payloads into higher-altitude orbits, as well as help explore the Moon and the outer space.
Russia's Deputy Prime Minister Dmitry Rogozin said last May Russia was considering whether to drop out of the international space station program to save funds for more promising space projects.
Media reports about a Russian orbital station started emerging last fall, with sources close to Rosatom citing 2017 as the program's projected launch year.
The plan to build a high-altitude space outpost was eventually confirmed last December by the chief of the state-run space agency, Oleg Ostapenko, who said it could also serve as a base for Russia's lunar program.
Ostapenko noted that a national space station would be “a step forward” for Russia and may serve “a number of different purposes,” for instance as a transfer point for the Russian lunar exploration program.
Reports have it that spacecraft will first be delivered to the new Russian space station, before continuing to the Moon.
Credit: sputniknews.com, rt.
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Posted: 25 Feb 2015 01:28 PM PST
Key science elements of the James Webb Space Telescope have been upgraded ahead of the observatory’s launch in 2018. The telescope, also known as JWST, is a joint project of NASA, ESA and the Canadian Space Agency. It carries a 6.5 m-diameter telescope and four state-of-the-art science instruments optimised for infrared observations. Europe has led the development of two of the instruments. As a general-purpose observatory, it will tackle a wide range of topics, including detecting the first galaxies in the Universe and following their evolution over cosmic time, witnessing the birth of new stars and their planetary systems, and studying planets in our Solar System and around other stars.
Installation of the four instruments in the telescope’s Integrated Science Instrument Module, or ISIM, was completed last April. Since then, the module has undergone extensive testing to ensure it can withstand the stresses of launch and operation in space.
A critical part of this process saw the instruments complete cryogenic testing in a round-the-clock campaign running for 116 days last summer.
Following the campaign, several months were dedicated to replacing key components of some of the instruments already known to require additional work before the next stages.
Europe’s ‘NIRSpec’, the near-infrared multi-object spectrograph, was one of the instruments upgraded. NIRSpec will split infrared light from distant stars and galaxies into its colour components – a spectrum – providing scientists with vital information on their chemical composition, age and distance.
The first generation of JWST’s highly sensitive near-infrared detectors were found to suffer from a design flaw that resulted in a progressive degradation of their performance. New detectors have now been installed in all three near-infrared instruments.
“Excellent detectors are crucial to the outstanding instrument performance needed when you want to look at the extremely distant and faint early stars and galaxies that formed when our Universe was still young, and the new detectors secure this top priority of NIRSpec and JWST,” says Pierre Ferruit, ESA’s JWST project scientist.
Early in June 2014, the ISIM was installed in the large Space Environment Simulator (SES) test chamber at NASA's Goddard Space Flight Center (GSFC) and on 16 June the door of the chamber was closed and the pump-down started; within 36 hours all the air had been evacuated. It then took a full week to check that ISIM, the four instruments and all the test equipment were still working correctly under ambient temperature conditions and that the cool-down could start.
Another crucial component of NIRSpec are its microshutter arrays, a new technology developed for JWST by NASA.
One of the defining and pioneering features of NIRSpec is its ability to analyse the light from more than 100 astronomical objects at the same time. This is made possible by an assembly of four microshutter arrays, totalling almost a quarter of a million individual shutters.
Armed with a pre-selected list of interesting targets, each shutter can be programmed to open or close individually. The light from the chosen targets passes through the selected open shutters before entering the next stage of the instrument, where it is split into a spectrum and projected onto the detectors for analysis.
But after testing in 2012 designed to simulate the extreme acoustic environment experienced during launch, it was discovered that several thousand microshutters in NIRSpec were jammed closed and could no longer open.
A thorough investigation performed with an engineering model of NIRSpec, including tests at NASA’s acoustic facility, found the root cause of the problem and new arrays were built.
The overall performance of the new microshutter assembly was found to be superior to the old system in many ways, and the delicate replacement operation was completed last month.
“This required the instrument’s outer cover to be opened and therefore an exceptionally strict cleanliness regime was needed to avoid contamination,” says Maurice te Plate, ESA’s JWST system integration and test manager.
“In particular, the microshutters are very sensitive to material such as small polyester fibres that can get stuck inside and prevent them from fully closing.
“We just completed our final checks and we are now ready to install NIRSpec back in to the Module.”
“NIRSpec is in its final flight configuration,” adds Peter Jensen, ESA’s JWST project manager. “We have now completed the endeavour we started 11 years ago – it has not been easy, but through skill, persistence, and dedication, the team has made it.”
Later this year, the module and instruments will resume the extensive programme of environmental tests to reproduce the conditions endured during launch and in space. The module will later be integrated into the JWST observatory for full-scale cryogenic optical and system testing before launch on an Ariane 5 from Europe’s Spaceport in Kourou, French Guiana.
Credit: ESA
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Posted: 25 Feb 2015 01:03 PM PST
India and Russia are planning to launch a research station towards the Moon in 2015 – the Chandrayaan-2. This was learned from the list of key projects for the current year, released on Tuesday by the Indian Space Research Organization (ISRO). The main task of the second Indian moon mission, the Chandrayaan-2, being carried out jointly by ISRO and Roscosmos, is to study the chemical composition of the surface of the Earth’s natural satellite.
To do this, they will launch an orbiter station to the Moon, which will then send a lander craft with an on-board Lunokhod. It will collect soil samples and carry out chemical analyses, transmitting the data to Earth.
Roscosmos is developing the Lunokhod and lander that will deliver it to the surface of the Earth’s natural satellite. It is expected that with the power supplied by solar panels, the Lunokhod will operate for about one year on the Moon.
The exact date of launch of this satellite, weighing 2,650 kg, from the Sriharikota Spaceport has not been announced yet.
The Chandrayaan-1 was launched on October 22, 2008, becoming the first mission of the Indian independent space program. The Chandrayaan-1 apparatus operated in the Moon’s orbit for 312 days, exploring its surface, including by means of an impact probe.
Credit: rbth.com
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Posted: 25 Feb 2015 12:42 PM PST
A newly discovered cosmic object may help provide answers to some long-standing questions about how black holes evolve and influence their surroundings, according to a new study using NASA’s Chandra X-ray Observatory. “In paleontology, the discovery of certain fossils can help scientists fill in the evolutionary gaps between different dinosaurs,” said Mar Mezcua of the Harvard-Smithsonian Center for Astrophysics, who led the study. “We do the same thing in astronomy, but we often have to ‘dig’ up our discoveries in galaxies that are millions of light years away.” The intriguing object, called NGC2276-3c, is located in an arm of the spiral galaxy NGC 2276, which is about 100 million light years from Earth. NGC2276-3c appears to be what astronomers call an “intermediate-mass black hole” (IMBH).
For many years, scientists have found conclusive evidence for smaller black holes that contain about five to thirty times the mass of the sun. There is also a lot of information about so-called supermassive holes that reside at the center of galaxies and weigh millions or even billions times the sun’s mass.
As their name suggests, IMBHs represent a class of black holes that fall in between these two well-established groups, with masses in the range of a few hundred to a few hundred thousand solar masses. One reason that IMBHs are important is that they could be the seeds from which supermassive black holes formed in the early universe.
“Astronomers have been looking very hard for these medium-sized black holes,” said co-author Tim Roberts of the University of Durham in the UK. “There have been hints that they exist, but the IMBHs have been acting like a long-lost relative that isn’t interested in being found.”
To learn about NGC2276-3c, the researchers observed it at almost the same time in X-rays with Chandra and in radio waves with the European Very Long Baseline Interferometry (VLBI) Network. The X-ray and radio data, along with an observed relation between radio and X-ray luminosities for sources powered by black holes, were used to estimate the black hole’s mass. A mass of about 50,000 times that of the sun was obtained, placing it in the range of IMBHs.
“We found that NGC2276-3c has traits similar to both stellar-mass black holes and supermassive black holes” said co-author Andrei Lobanov of the Max Planck Institute for Radio Astronomy in Bonn, Germany. “In other words, this object helps tie the whole black hole family together.”
In addition to its mass, another remarkable property of NGC2276-3c is that it has produced a powerful radio jet that extends up to 2,000 light years. The region along the jet that extends for about 1,000 light years from NGC2276-3c seems to be missing young stars. This provides evidence that the IMBH may have had a strong influence on its environment, as the jet could have cleared out a cavity in the gas and suppressed the formation of new stars. Further studies of the NGC2276-3c jet could provide insight into the potentially large effects that supermassive black hole seeds in the early universe have had on their surroundings.
The location of this IMBH in a spiral arm of NGC 2276 raises other questions. Was it formed within the galaxy, or did it come from the center of a dwarf galaxy that collided and merged with NGC 2276 in the past?
This IMBH is one of eight ultraluminous X-ray sources (ULXs) in NGC 2276 studied by Anna Wolter of the National Institute for Astrophysics (INAF) in Milan, Italy, and her colleagues. Hundreds of ULXs have been detected in the last 30 years; however, the nature of these sources is still a matter of debate, with some thought to contain IMBHs. Chandra observations show that one apparent ULX observed by ESA’s XMM-Newton is actually five separate ULXs, including NGC2276-3c. Wolter’s study concluded that about five to fifteen solar masses worth of stars are forming each year in NGC 2276. This high rate of star formation may have been triggered by a collision with a dwarf galaxy, supporting the merger idea for the IMBH’s origin.
The study on NGC 2276-3c was conducted by Mar Mezcua (previously in the Instituto de Astrofisica de Canarias and now at the Harvard-Smithsonian Center for Astrophysics), Tim Roberts (University of Durham, UK), Andrei Lobanov (Max Planck Institute for Radio Astronomy, Germany), and Andrew Sutton (University of Durham) and will appear in the Monthly Notices of the Royal Astronomical Society (MNRAS). A separate paper on the ULX population in NGC 2276 will also appear in MNRAS and the authors on that study are Anna Wolter (National Institute for Astrophysics (INAF) in Milan, Italy), Paolo Esposito (INAF), Michela Mapelli (INAF, Padova), Fabio Pizzolato (University of Milan, Italy), and Emanuele Ripamonti (University of Padova, Italy).
The results from Mezcua and Wolter and their colleagues will appear in separate papers in the Monthly Notices of the Royal Astronomical Society. The Mezcua paper and Wolter paper are also available online. 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.
Credit: chandra.si.edu
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Posted: 25 Feb 2015 11:45 AM PST
Former Soviet cosmonaut Alexei Gubarev, who commanded a month-long mission to the Soviet Union’s Salyut 4 space station in early 1974 and later led the first international orbital voyage to Salyut 6, teamed with Czechoslovakia’s Vladimir Remek, in March 1978, has died on Feb. 21, aged 83. Gubarev's death was reported by the Gagarin Cosmonaut Training Center in Star City outside of Moscow, where he had prepared for his two space missions. "The management and employees of the training center express our sincere condolences to the family, relatives, friends and relatives of [Alexei] Gubarev," officials at the center wrote in a statement released Tuesday.
Gubarev graduated from the Soviet Naval Aviation School in 1952 and went on to serve with the Soviet Air Force. He undertook further studies at the Gagarin Air Force Academy before acceptance into the space programme.
He was originally trained for the Soviet lunar programme and for military Soyuz flights before training for Salyut missions. His next mission, in 1978, was Soyuz 28, the first Interkosmos flight, where he was accompanied by Vladimír Remek from Czechoslovakia.
He resigned as a cosmonaut in 1981 and took up an administrative position at the Gagarin Cosmonaut Training Centre.
In the 1980s he worked at the 30th Central Scientific Research Institute, Ministry of Defence (Russia).
"The news of the death of my friend Alexei Gubarev came unexpectedly," Remek, who is now Czech Ambassador to Russia wrote on the embassy's website on Tuesday. We were planning to celebrate the anniversary of our flight [on] March 2."
"I feel great sadness. One whole stage of my life has left with Alexei," Remek wrote.
Credit: collectspace.com, amer
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Posted: 25 Feb 2015 11:14 AM PST
The next launch of the Angara-A5 heavy lift carrier rocket will be carried out in the first half of 2016, a rocket and space industry source told TASS on Tuesday. "The next Angara flight is scheduled for the first half of 2016," he said. The rocket’s general designer Vladimir Nesterov said previously that the second heavy Angara rocket would be delivered to Russia’s military on late 2015. The first test launch of the light version of the Angara rocket was carried out on July 9, 2014, and its heavy version with the Briz-M upper stage was launched on December 23.
Angara is a new-generation carrier rocket based on a universal module with oxygen-kerosene engines. The family includes carriers from the light to heavy class with the payload capacity from 1.5 to 25 tonnes.
Angara is a modular series of rockets designed to launch different classes of payloads to various orbits. The heavy-lift version will enable Russia to launch geostationary-orbiting satellites from its own territory. Currently such satellites are launched from the Baikonur Cosmodrome in Kazakhstan aboard the Proton rocket, which uses a highly toxic hydrazine fuel.
The rocket has universal modules - one for light-class carriers, three - for medium-class carriers and five - for heavy carriers. The series production of the universal rocket module (URM-1 - first stage of a light carrier rocket and first and second stage of a heavy rocket) will be carried out in the Omsk-based Polyot Production Association - a branch of the Khrunichev Stare Research and Production Space Centre. The universal rocket module URM-2 (the second stage of a light carrier rocket and third stage of a heavy rocket) will be manufactured at the Moscow-based rocket and space plant.
The brand new Angara rocket is the first space booster designed from scratch in Russia since the collapse of the Soviet Union. The development of the rocket family began at the Moscow-based Khrunichev Centre back in 1994. Two decades of design work and scientific research have cost the government approximately $3 billion.
Credit: TASS
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2015년 2월 26일 목요일
Astro Watch
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