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Posted: 27 Feb 2015 03:56 PM PST
The US-Russian crew of Expedition 43 to the International Space Station (ISS) is intensively training for the upcoming orbital mission. NASA astronaut Scott Kelly along with Russian cosmonauts Mikhail Kornienko and Gennady Padalka are scheduled to be launched to ISS Mar. 27, 2015 from Baikonur cosmodrome in Kazakhstan. For Kelly and Kornienko it will be a special mission, they will perform the first one-year stay at the Space Station. Recently, the crew passed the exams at the Gagarin Research and Testing Cosmonaut Training Center in Star City, Russia.
Crew commander Padalka has successfully passed the examination on the Teleoperator-2 simulator. The simulator is designed for long-term expedition crews to practice manual remote control of pilotless objects from the ISS. In case of emergency, the cosmonauts must be able to tie up and dock the spacecraft manually.
The members of the primary and backup crews were examined on the Don-Soyuz simulator. On Feb. 18, Padalka and Kornienko demonstrated to the examination commission their excellent skills of redocking and manual tying up of a spacecraft at the station.
They have also successfully coped with the task of "landing" as close as possible to the designated point, experiencing minimal overload.
In the coming days, both main and backup crew will practice a "typical flight day" on a simulator of the Russian segment of the ISS.
On Mar. 4, the crew will begin the final stage of the pre-flight training - a comprehensive exam training.
Meanwhile, an intensive pre-launch processing of Russian Soyuz TMA-16M manned spacecraft continues at Baikonur. On Feb. 16, the air-tightness testing of Soyuz was carried out in the assembly, integration and test building, of the cosmodrome’s pad 2B.
The works in the low-pressure chamber were successfully completed on Feb. 24, and the manned spacecraft was moved to the working place at the cosmodrome’s pad 254, where the experts of the Russian rocket and space industry enterprises unloaded Soyuz TMA-16M from the carriage, installed it on the stand, and connected the ground-based equipment to the spacecraft. The autonomous tests of the spacecraft are continuing.
Researchers expect the upcoming one-year mission to yield beneficial knowledge on the medical, psychological and biomedical challenges explorers may face as they venture to an asteroid, Mars and beyond. This mission will also provide an additional opportunity for cooperation between research teams around the world.
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Posted: 27 Feb 2015 03:14 PM PST
A Soyuz-2.1a carrier rocket with Bars-M military satellite blasted off from the Plesetsk space center in northwestern Russia’s Arkhangelsk Region, a defense ministry spokesman Col. Alexei Zolotukhin told RIA Novosti Friday. The blastoff took place as scheduled, at 2:01 p.m. Moscow time [11:01 GMT]. The military satellite separated from the rocket's third stage eight minutes after takeoff as planned. Bars-M No.1L is the first of a new series of area reconnaissance satellites, designed to produce wider-angle images of the Earth than Russia’s other reconnaissance satellites such as Persona. Its images, which have a lower resolution than its counterparts, can be used for cartography and analysis of wider areas.
The Bars-M series of satellites, designated 11F148, replaces the Yantar-1KFT film-return satellites operated by Russia, and previously the Soviet Union, between 1981 and 2005.
It was the first launch from Plesetsk this year. The previous Soyuz-2.1a launch from the northwestern Russian launch center took place on October 30, 2014.
This was the 21st Soyuz-2.1a, 1b and 1c type carrier rocket launched from Plesetsk since flight tests have began there on November 8, 2004.
Earlier this month, a space industry source told RIA Novosti the Soyuz-2.1a rocket would orbit another military satellite.
Soyuz-2 replaced the Soyuz-U carrier rocket, which was in commission at the Plesetsk space center from 1973 to 2012. Over that period, nearly 430 multi-purpose space vehicles were sent into orbit out of a total 434 launches.
In September and October 2014, Russian Deputy Prime Minister Dmitry Rogozin and Russian Armed Forces communications head Maj. Gen. Khalil Arslanov expressed confidence that nine military communications satellites would join the orbital group by 2020.
Credit: sputniknews.com, nasas
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Posted: 27 Feb 2015 01:56 PM PST
Liquid water is a requirement for life on Earth. But in other, much colder worlds, life might exist beyond the bounds of water-based chemistry. Taking a simultaneously imaginative and rigidly scientific view, Cornell chemical engineers and astronomers offer a template for life that could thrive in a harsh, cold world – specifically Titan, the giant moon of Saturn. A planetary body awash with seas not of water, but of liquid methane, Titan could harbor methane-based, oxygen-free cells that metabolize, reproduce and do everything life on Earth does. Their theorized cell membrane, composed of small organic nitrogen compounds and capable of functioning in liquid methane temperatures of 292 degrees below zero, is published in Science Advances, Feb. 27. The work is led by chemical molecular dynamics expert Paulette Clancy, the Samuel W. and Diane M. Bodman Professor of Chemical and Biomolecular Engineering, with first author James Stevenson, a graduate student in chemical engineering. The paper’s co-author is Jonathan Lunine, the David C. Duncan Professor in the Physical Sciences in the College of Arts and Sciences’ Department of Astronomy.
Lunine is an expert on Saturn’s moons and an interdisciplinary scientist on the Cassini-Huygens mission that discovered methane-ethane seas on Titan. Intrigued by the possibilities of methane-based life on Titan, and armed with a grant from the Templeton Foundation to study non-aqueous life, Lunine sought assistance about a year ago from Cornell faculty with expertise in chemical modeling. Clancy, who had never met Lunine, offered to help.
“We’re not biologists, and we’re not astronomers, but we had the right tools,” Clancy said. “Perhaps it helped, because we didn’t come in with any preconceptions about what should be in a membrane and what shouldn’t. We just worked with the compounds that we knew were there and asked, ‘If this was your palette, what can you make out of that?’”
On Earth, life is based on the phospholipid bilayer membrane, the strong, permeable, water-based vesicle that houses the organic matter of every cell. A vesicle made from such a membrane is called a liposome. Thus, many astronomers seek extraterrestrial life in what’s called the circumstellar habitable zone, the narrow band around the sun in which liquid water can exist. But what if cells weren’t based on water, but on methane, which has a much lower freezing point?
The engineers named their theorized cell membrane an “azotosome,” “azote” being the French word for nitrogen. “Liposome” comes from the Greek “lipos” and “soma” to mean “lipid body;” by analogy, “azotosome” means “nitrogen body.”
The azotosome is made from nitrogen, carbon and hydrogen molecules known to exist in the cryogenic seas of Titan, but shows the same stability and flexibility that Earth’s analogous liposome does. This came as a surprise to chemists like Clancy and Stevenson, who had never thought about the mechanics of cell stability before; they usually study semiconductors, not cells.
The engineers employed a molecular dynamics method that screened for candidate compounds from methane for self-assembly into membrane-like structures. The most promising compound they found is an acrylonitrile azotosome, which showed good stability, a strong barrier to decomposition, and a flexibility similar to that of phospholipid membranes on Earth. Acrylonitrile – a colorless, poisonous, liquid organic compound used in the manufacture of acrylic fibers, resins and thermoplastics – is present in Titan’s atmosphere.
Excited by the initial proof of concept, Clancy said the next step is to try and demonstrate how these cells would behave in the methane environment – what might be the analogue to reproduction and metabolism in oxygen-free, methane-based cells.
Lunine looks forward to the long-term prospect of testing these ideas on Titan itself, as he put it, by “someday sending a probe to float on the seas of this amazing moon and directly sampling the organics.”
Stevenson said he was in part inspired by science fiction writer Isaac Asimov, who wrote about the concept of non-water-based life in a 1962 essay, “Not as We Know It.”
“Ours is the first concrete blueprint of life not as we know it,” Stevenson added.
Credit: cornell.edu
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Posted: 27 Feb 2015 01:14 PM PST
The tunable laser spectrometer in the SAM (Sample Analysis at Mars) instrument of NASA's Curiosity rover has unequivocally detected an episodic increase in the concentration of methane in Mars' atmosphere after an exhaustive analysis of data obtained during 605 sols or Martian days. This has been revealed in an article authored by scientists from the MSL (Mars Science Laboratory) mission, recently published in Science. One of the authors of this article is Francisco Javier Martín-Torres, a researcher at the Andalusian Institute of Earth Sciences (CSIC-UGR) in Spain. This puts an end to the long controversy on the presence of methane on Mars, which started over a decade ago when this gas was first detected with telescopes from Earth. The controversy increased afterwards with the measurements obtained by orbiting satellites, some of which were occasionally contradictory. These new and incontrovertible data open paths for new research that can identify the sources that produce this gas--which could include some type of biological activity--and the mechanisms by means of which the gas is eliminated with such inexplicable speed.
Ever since the Telescope in the Mauna Kea Canada-France-Hawaii Observatory first announced the detection of methane in the Martian atmosphere, several other measurements of the gas have been conducted by means of a diversity of instruments, both remotely from earth, and also by means of satellites like the Mars Express and the Mars Global Surveyor.
Since methane can be the product of biological activity--practically all the existing methane in Earth's atmosphere originates in this way--this has created great expectations that Martian methane could also be of a similar origin.
Methane on Mars
These observations appeared to be contradictory. Some of them suggested a distribution pattern that was limited in space (with its source in the Northern hemisphere) and time (with a peak of concentration during summer in the Northern hemisphere and its subsequent vanishing in just a matter of months). Both facts are inexplicable by available photochemical and general circulation models, which are currently used to define our understanding of Martian atmosphere.
According to these models, if there really existed methane on Mars, it would remain there for an average 300 years, and during this period it would be homogeneously distributed across the atmosphere. Since we lack a model that can account for its generation, localization and swift disappearance, detections were all called in doubt, and the results were attributed to the instruments employed in their detection, which were working on the very limit of their capacity, and also to the fact that the concentration values of the gas that they yielded were of the ppbv order (parts per billion by volume).
"Within this context, and when we were all almost fully persuaded that the data we had so far collected were at the very least rough it not fully invalid, the expectations to decide on this were bestowed upon the capacity of the SAM instrument to come up with more precise measurements", says this researcher at the Andalusian Institute of Earth Sciences.
By means of its TLS unit, SAM has been detecting basal levels of methane concentration of around 0,7 ppbv, and has confirmed an event of episodic increase of up to ten times this value during a period of sixty sols (Martian days), i.e., of about 7 ppvb.
The new data are based on observations during almost one Martian year (almost two Earth years), included in the initial prediction for the duration of the mission (nominal mission), during which Curiosity has surveyed about 8 kms in the basin of the Gale crater.
Martian seasons
During this period, which comprehends all the full cycle of Martian seasons, the reference to the environmental data collected by the meteorological REMS (Rover Environmental Monitoring Station) station has allowed for the establishment of possible correlations with the environmental parameters that this instrument records: relative humidity, temperature and atmospheric opacity. Data on atmospheric opacity was obtained both by the UV sensor in REMS and also by MastCam (Mast Camera), the camera at Curiosity, which is employed for support in atmospheric surveys.
REMS is an instrument that has been developed and it is being scientifically exploited by Spanish researchers, some of whom have been members of the team that has conducted this important research. The hypothetical existence of seasonal variations in methane concentration in correlation with certain environmental variables, in any case, will be only confirmed through sustained measurements in the future, specifically oriented to establish which factors can determine the sporadic emission and subsequent degradation of this gas in Mars. As far as the spatial disposition of the methane plumes, they have concluded that they are generated in very brief and weak events and in very specific places.
TLS is a two-channel tunable laser spectrometer which analyses in the infrared region--more specifically in a 2,7 μm wavelength through the first channel, and 3,27 μm through the second. The latter channel is specifically prepared for the detection of methane. It has a resolution of 0,0002 cm-1, which allows for the detection of methane through its spectrographic footprint of three very clearly defined lines, and the procedure which is applied (laser light absorption through a sample contained in a closed cell) "is simple, non-invasive and sensitive" as the article itself claims.
Small margin of error
The containing cell can be full of Martian environment or as a vacuum to make contrasting measurements, which include some conducted through artificially increased concentrations, "which has resulted in a very reduced margin for error and guarantees the accuracy of results, which can now be deemed definitively conclusive", says Martín-Torres.
According to him, the new questions posed by these results far outnumber the answers it does provide. "It is a finding that puts paid to the question of the presence of methane in the Martian atmosphere, but it does pose some other more complex and far-reaching questions, such as the nature of its sources--which must lie, we believe, in one or two additional sources that were not originally contemplated in the models used so far. Among these sources, we must not rule out biological methanogenesis. Another new question is related to the bizarre evolution of methane in the Martian atmosphere after its emission. Both questions should be addressed in the future with specifically designed new research."
The newly arrived MAVEN (Mars Atmosphere and Volatile Evolution) from NASA will immediately provide continuity for the study of this subject, and in the near future the Trace Gas Orbiter (TGO), jointly developed by the European Space Agency (ESA) and the Russian Space Agency (Ruscosmos), which is also part of the ExoMars mission, will measure the concentration of methane at larger scale, and it will allow for the establishment of a framework to contextualize the results obtained, and deepen our knowledge of methane dynamics in Mars.
Credit: eurekalert.org
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Posted: 27 Feb 2015 12:47 PM PST
Researchers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered regions where certain organic molecules somehow endure the intense radiation near the supermassive black hole at the center of galaxy NGC 1068, also known to amateur stargazers as M77. Such complex carbon-based molecules are thought to be easily obliterated by the strong X-rays and ultraviolet (UV) photons that permeate the environment surrounding supermassive black holes. The new ALMA data indicate, however, that pockets of calm exist even in this tumultuous region, most likely due to dense areas of dust and gas that shield molecules from otherwise lethal radiation.
Molecules Reveal Clues to Galactic Environments
Interstellar gas contains a wide variety of molecules, which differ wildly depending on the environment. For example, high-temperature, active star forming regions produce different molecules than would be found in colder interstellar regions. This enables scientists to probe the temperature and density of certain regions by studying their chemical composition.
Astronomers have long been studying the molecular signatures around supermassive black holes: both nearby starburst regions and surrounding rings of dust and gas known as a circumnuclear disks (CND) that spiral-in to feed an active black hole. These regions are important for understanding the evolution of galaxies. However, weak radio emission from the molecules there often makes observations difficult.
ALMA Observations Trace Molecules
To better understand the complex and energetic environs around a supermassive black hole, the research team -- led by Shuro Takano at the National Astronomical Observatory of Japan (NAOJ) and Taku Nakajima at Nagoya University -- observed the spiral galaxy M77, which is located about 47 million light-years from Earth in the direction of the constellation Cetus (the Whale).
This galaxy is known to have an actively feeding central black hole, which indicates it has a substantial circumnuclear disk. That disk, in turn, is surrounded by a 3,500 light-year wide starburst ring. To probe these areas, the research team added ALMA’s extreme sensitivity and high-fidelity imaging capabilities to earlier observations conducted by the 45-meter radio telescope at the Nobeyama Radio Observatory of the National Astronomical Observatory of Japan (NAOJ).
The new ALMA observations clearly reveal the distributions of nine types of molecules in the surrounding disk and starburst ring.
“In this observation, we used only 16 antennas, which are about one-fourth of the complete number of ALMA antennas, but it was really surprising that we could get so many molecular distribution maps in less than two hours. We have never obtained such a quantity of maps in one observation,” said Takano, the leader of the research team.
The results clearly show that the molecular distribution varies according to the type of molecule. While carbon monoxide (CO) is distributed mainly in the starburst ring, five types of molecules, including complex organic molecules such as cyanoacetylene (HC3N) and acetonitrile (CH3CN), are concentrated primarily in the CND. In addition, carbon monosulfide (CS) and methanol (CH3OH) are distributed both in the starburst ring and the CND.
Shielding Complex Organics around a Black Hole
As the supermassive black hole devours the surrounding material, this disk is heated to such extreme temperatures that it emits intense X-rays and UV photons. When complex organic molecules are exposed to these photons, their atomic bonds are broken and the molecules are destroyed. Astronomers assumed that such regions would therefore be devoid of such complex organics. The ALMA observations, however, proved the contrary: Complex organic molecules are abundant in the CND, though not so in the broader starburst region.
"It was quite unexpected that complex molecules with a large number of atoms like acetonitrile and cyanoacetylene are concentrated around the black hole's disk," said Nakajima.
The research team speculates that organic molecules remain intact in the CND due to the large amount of gas there, which acts as a barrier for the X-rays and UV photons, while organic molecules cannot survive the exposure to the strong UV photons in the starburst region where the gas density is comparatively lower.
The researchers point out that these results are a significant first step in understanding the structure, temperature, and density of gas surrounding the active black hole in M77. “We expect that future observations with wider bandwidth and higher resolution will show us the whole picture of this region," said Takano.
“ALMA has launched an entirely new era in astrochemistry,” said Eric Herbst of the University of Virginia in Charlottesville and a member of the research team. “Detecting and tracing molecules throughout the cosmos enables us to learn so much more about otherwise hidden areas, like the regions surrounding the black hole in M77.”
These results were published by Takano et al. as “Distributions of molecules in the circumnuclear disk and surrounding starburst ring in the Seyfert galaxy NGC 1068 observed with ALMA” (in the astronomical journal Publications of the Astronomical Society of Japan (PASJ), issued in August 2014) and by Nakajima et al. “A Multi-Transition Study of Molecules toward NGC 1068 based on High-Resolution Imaging Observations with ALMA” (in PASJ issued in February 2015).
Credit: nrao.edu
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2015년 2월 28일 토요일
Astro Watch
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