- Space Station Crew Returns to Earth
- Ocean on Enceladus May Harbor Hydrothermal Activity
- Sun Emits Significant Solar Flare
- Space Launch System Booster Passes Major Test
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Posted: 12 Mar 2015 12:39 AM PDT
Three crew members returned to Earth Wednesday after a 167-day mission on the International Space Station (ISS) that included hundreds of scientific experiments and several spacewalks to prepare the orbiting laboratory for future arrivals by U.S. commercial crew spacecraft. Expedition 42 commander Barry Wilmore of NASA and flight engineers Alexander Samokutyaev and Elena Serova of the Russian Federal Space Agency (Roscosmos) touched down at approximately 10:07 p.m. EDT (8:07 a.m. March 12, Kazakh time) southeast of the remote town of Dzhezkazgan in Kazakhstan. The landing of the capsule of Russia's Soyuz TMA-14M manned spacecraft with the crew went as planned and the crew is feeling well, Russian Deputy Prime Minister Dmitry Rogozin said Thursday. "Everything goes as planned here. The crew was evacuated from the capsule. They are feeling well," Rogozin said on Twitter.
During their time on station, the crew members participated in a variety of research focusing on the effects of microgravity on cells, Earth observation, physical science and biological and molecular science. One of several key research focus areas during Expedition 42 was human health management for long-duration space travel, as NASA and Roscosmos prepare for two crew members to spend one year aboard the space station.
The space station also serves as a test bed to demonstrate new technology. The Cloud-Aerosol Transport System (CATS) arrived and was installed during Expedition 42, and already is providing data to improve scientists’ understanding of the structure and evolution of Earth's atmosphere. This may lead to enhancements to spacecraft launches, landings and communications systems; help guide future atmospheric investigations of Mars, Jupiter or other worlds; and help researchers model and predict climate changes on Earth.
The newly installed Electromagnetic Levitator will allow scientists to observe fundamental physical processes as liquid metals cool, potentially leading to lighter, higher-performing alloy, mixtures of two or more metals or a metal and another material, for use on Earth and in space.
The station crew also welcomed three cargo spacecraft with several tons of scientific investigations, food, fuel and other supplies. In January, the trio helped grapple and connect a SpaceX Dragon spacecraft on the company's fifth contracted commercial resupply mission to the station. The Dragon returned to Earth in February with critical science samples. Two Russian ISS Progress cargo craft docked to the station in October and February. The fifth and final European Automated Transfer Vehicle, bearing the name of Belgian physicist Georges Lemaître, considered the father of the big-bang theory, departed the station in February.
During his time on the orbital complex, Wilmore ventured outside the space station with NASA astronaut Terry Virts on three spacewalks to prepare for new international docking adapters and future U.S. commercial crew spacecraft. Wilmore also completed a spacewalk in October with fellow NASA astronaut Reid Wiseman to replace a failed voltage regulator. Samokutyaev conducted one spacewalk during his time in space.
Having completed his second space station mission, Samokutyaev now has spent 331 days in space. Wilmore, having previously flown as a shuttle pilot on STS-129, has spent 178 days in space. Serova spent 167 days in space on her first flight.
Expedition 43 currently is operating the station, with Virts in command. Flight engineers Anton Shkaplerov of Roscosmos and Samantha Cristoforetti of ESA (European Space Agency), are continuing station research and operations until three new crewmates arrive in two weeks. NASA’s Scott Kelly and Roscosmos’ Mikhail Kornienko and Gennady Padalka are scheduled to launch from Kazakhstan March 27, Eastern time. Kelly and Kornienko will embark on the first joint U.S.-Russian one-year mission, an important stepping stone on NASA’s journey to Mars.
Credit: NASA
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Posted: 11 Mar 2015 04:48 PM PDT
Tiny grains of rock detected by the international Cassini spacecraft orbiting Saturn point to hydrothermal activity on the seafloor of its icy moon Enceladus. The finding adds to the tantalising possibility that the moon could contain environments suitable for living organisms. Understanding the interior structure of 500 km-diameter Enceladus has been a top priority of the Cassini mission since plumes of ice and water vapour were discovered jetting from fractures at the moon’s south pole in 2005. The results are being published March 12 in the journal Nature. "It's very exciting that we can use these tiny grains of rock, spewed into space by geysers, to tell us about conditions on -- and beneath -- the ocean floor of an icy moon," said Research Associate Sean Hsu at University of Colorado Boulder's Laboratory for Atmospheric and Space Physics (LASP), lead author on the paper.
The Cassini-Huygens mission to study the gaseous planet Saturn and its moons was launched in 1997 by NASA, ESA and the Italian Space Agency ASI and comprises the Cassini orbiter and the Huygens atmospheric probe. In 2005, the mission first revealed geologic activity on Enceladus with evidence of icy geysers. Results of investigations in Enceladus’ gravitational field published in 2014 strongly suggest the presence of a 10-kilometer-deep ocean beneath an ice shell 30 to 40 kilometers thick. The new results follow an extensive four-year analysis of data from the Cassini Cosmic Dust Analyzer (CDA) as well as computer simulations and laboratory experiments. Cassini had repeatedly detected tiny particles of rock that contained silicon and orbited Saturn at the same distance as Enceladus.
“These findings add to the possibility that Enceladus, which contains a subsurface ocean and displays remarkable geologic activity, could contain environments suitable for living organisms,” said John Grunsfeld astronaut and associate administrator of NASA's Science Mission Directorate in Washington. “The locations in our solar system where extreme environments occur in which life might exist may bring us closer to answering the question: are we alone in the Universe.”
Hydrothermal activity occurs when seawater infiltrates and reacts with a rocky crust and emerges as a heated, mineral-laden solution, a natural occurrence in Earth's oceans. According to two science papers, the results are the first clear indications an icy moon may have similar ongoing active processes.
The first paper, published this week in the journal Nature, relates to microscopic grains of rock detected by Cassini in the Saturn system. An extensive, four-year analysis of data from the spacecraft, computer simulations and laboratory experiments led researchers to the conclusion the tiny grains most likely form when hot water containing dissolved minerals from the moon's rocky interior travels upward, coming into contact with cooler water. Temperatures required for the interactions that produce the tiny rock grains would be at least 194 degrees Fahrenheit (90 degrees Celsius).
CDA instrument repeatedly detected miniscule rock particles rich in silicon, even before Cassini entered Saturn's orbit in 2004. By process of elimination, the CDA team concluded these particles must be grains of silica, which is found in sand and the mineral quartz on Earth. The consistent size of the grains observed by Cassini, the largest of which were 6 to 9 nanometers, was the clue that told the researchers a specific process likely was responsible.
On Earth, the most common way to form silica grains of this size is hydrothermal activity under a specific range of conditions; namely, when slightly alkaline and salty water that is super-saturated with silica undergoes a big drop in temperature.
"We methodically searched for alternate explanations for the nanosilica grains, but every new result pointed to a single, most likely origin," said co-author Frank Postberg, a Cassini CDA team scientist at Heidelberg University in Germany.
Hsu and Postberg worked closely with colleagues at the University of Tokyo who performed the detailed laboratory experiments that validated the hydrothermal activity hypothesis. The Japanese team, led by Yasuhito Sekine, verified the conditions under which silica grains form at the same size Cassini detected. The researchers think these conditions may exist on the seafloor of Enceladus, where hot water from the interior meets the relatively cold water at the ocean bottom.
The extremely small size of the silica particles also suggests they travel upward relatively quickly from their hydrothermal origin to the near-surface sources of the moon's geysers. From seafloor to outer space, a distance of about 30 miles (50 kilometers), the grains spend a few months to a few years in transit, otherwise they would grow much larger.
The authors point out that Cassini's gravity measurements suggest Enceladus' rocky core is quite porous, which would allow water from the ocean to percolate into the interior. This would provide a huge surface area where rock and water could interact.
The second paper, recently published in Geophysical Research Letters, suggests hydrothermal activity as one of two likely sources of methane in the plume of gas and ice particles that erupts from the south polar region of Enceladus. The finding is the result of extensive modeling by French and American scientists to address why methane, as previously sampled by Cassini, is curiously abundant in the plume.
The team found that, at the high pressures expected in the moon's ocean, icy materials called clathrates could form that imprison methane molecules within a crystal structure of water ice. Their models indicate that this process is so efficient at depleting the ocean of methane that the researchers still needed an explanation for its abundance in the plume.
In one scenario, hydrothermal processes super-saturate the ocean with methane. This could occur if methane is produced faster than it is converted into clathrates. A second possibility is that methane clathrates from the ocean are dragged along into the erupting plumes and release their methane as they rise, like bubbles forming in a popped bottle of champagne.
The authors agree both scenarios are likely occurring to some degree, but they note that the presence of nanosilica grains, as documented by the other paper, favors the hydrothermal scenario.
"We didn't expect that our study of clathrates in the Enceladus ocean would lead us to the idea that methane is actively being produced by hydrothermal processes," said lead author Alexis Bouquet, a graduate student at the University of Texas at San Antonio. Bouquet worked with co-author Hunter Waite, who leads the Cassini Ion and Neutral Mass Spectrometer (INMS) team at Southwest Research Institute in San Antonio.
"Ten years ago it was a big mystery why the nano-grains were made of silica rather than water ice," said Sascha Kempf of LASP. "Now we know the observations were correct. We know where the silica particles are coming from, and why we are seeing them. We learned something very unexpected, which is why I really like this study."
“This moon has all the ingredients – water, heat, and minerals – to support habitability in the outer Solar System, confirming the astrobiological potential of Enceladus,” added Nicolas Altobelli, ESA’s Cassini project scientist. “Enceladus may even represent a very common habitat in the Galaxy: icy moons around giant gas planets, located well beyond the ‘habitable zone’ of a star, but still able to maintain liquid water below their icy surface.”
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Posted: 11 Mar 2015 02:24 PM PDT
The sun emitted a significant solar flare, peaking at 12:22 p.m. EDT on March 11, 2015. This flare is classified as an X2.2-class flare. X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc. NASA’s Solar Dynamics Observatory, which watches the sun constantly, captured an image of the event. Extreme ultraviolet radiation from the explosion ionized the upper layers of Earth's atmosphere, causing HF radio fade-outs and other propagation effects on the dayside of our planet. Ham radio operators and mariners may have noticed brief but complete blackout conditions at frequencies below 10 MHz. The disturbance has since subsided.
This is yet another significant solar flare from Active Region 12297 as it marches across the solar disk. This is the largest flare the region has produced so far, after producing a slew of R1 (Minor) and R2 (Moderate) Radio Blackouts over the past few days.
Natural radio emissions from the sun, which are produced by shock waves in the sun's atmosphere, suggest that a coronal mass ejection (CME) is emerging from the blast site at speeds exceeding 1,400 km/s (3.1 million mph).
A slight chance for (R3 or greater) radio blackouts remains for the next three days (Mar. 11-13) as Region 2297 maintains its size and complex magnetic structure.
G1 (minor) geomagnetic storms are likely on Mar. 13 as the brunt of the CME impacts are expected to begin.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel.
To see how this event may affect Earth, please visit NOAA's Space Weather Prediction Center athttp://spaceweather.gov, the U.S. government's official source for space weather forecasts, alerts, watches and warnings.
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Posted: 11 Mar 2015 12:58 PM PDT
NASA and Orbital ATK today conducted the first qualification ground test of the five-segment rocket motor that will be used for NASA’s heavy-lift Space Launch System (SLS), which is being designed to enable exciting new exploration missions throughout the solar system. The successful pre-flight test, known as Qualification Motor 1 (QM-1), is an important milestone in validating the rocket motor’s use for SLS and its deep space missions. Initial test data indicate the motor performed as designed and delivered the anticipated performance. The rocket motor produced approximately 3.6 million pounds of thrust (equivalent to 22 million horsepower) and fired for just over two minutes. More data will be available as post-test analysis is accomplished on the 102 design objectives that are supported by 531 instrumentation channels.
“This motor firing is the first of two qualification tests to certify the motor configuration for NASA’s Space Launch System,” said Charlie Precourt, Vice President and General Manager of Orbital ATK’s Propulsion Systems Division, and four-time space shuttle astronaut. “The data from today and from our three development motor tests, along with information we have collected on hundreds of predecessor motors over the past three decades, confirms this is the most capable and powerful solid rocket motor ever designed.”
Measuring 12 feet in diameter and 154 feet in length, Orbital ATK’s five-segment motor is the largest human-rated solid rocket motor built today. When it is fully assembled as a booster, it will be 177 feet tall (approximately 17 stories). It produces 20 percent more power than the previously-used four-segment motor, and it also uses new materials that provide cost and weight savings. The five-segment motor was designed to maximize safety while providing a reliable and affordable launch capability for human missions deeper in the solar system than we have ever gone before – including to the surface of Mars.
“NASA’s SLS, along with the Orion crew capsule, enables us to blaze new trails, and embark on missions to deep space that leverage more than five decades of pushing boundaries,” said Blake Larson, Orbital ATK’s Chief Operating Officer. “Deep space missions require a heavy-lift vehicle to ensure success, and SLS and Orion can accomplish a deep space mission in fewer launches than current or planned vehicles.”
Today’s qualification test included newly-designed avionics hardware and equipment to control the motor and provide improved test monitoring capability. Other test improvements include a new main pivot flexure design in the forward thrust block to transfer the massive forces from the test into the various load cells for thrust monitoring, as well as an added mid-span support that assisted in adjusting the motor centerline to make the test more consistent with actual flight conditions.
"The work being done around the country today to build SLS is laying a solid foundation for future exploration missions, and these missions will enable us to pioneer far into the solar system," said William Gerstenmaier, NASA’s associate administrator for human exploration and operations. "The teams are doing tremendous work to develop what will be a national asset for human exploration and potential science missions."
“This is an exciting time for exploration, as we venture farther into space,” said Precourt. “The promise of deep space exploration will inspire the next generation to pursue careers in science, technology, engineering and math – preparing them to run the missions we’re designing.”
NASA’s SLS will launch on its first mission, Exploration Mission-1, in just a few years. The next major milestones for SLS include Boeing’s Vertical Assembly Center core stage welding, continued testing of Aerojet Rocketdyne’s RS-25 engine at NASA’s Stennis Space Center, avionics and controls testing at Marshall Space Flight Center, and Orbital ATK’s QM-2 static firing next year.
The SLS and Orion programs are supported by a network of hundreds of suppliers representing 47 states. Orbital ATK has 29 key SLS booster suppliers across 16 states.
"This test is a significant milestone for SLS and follows years of development," said Todd May, SLS program manager at NASA. "Our partnership with Orbital ATK and more than 500 suppliers across the country is keeping us on the path to building the most powerful rocket in the world."
Credit: orbitalatk.com, NASA
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