Sep 15 2015
From The Space Library
Release C15-037 NASA Awards Mechanical Integrated Services, Technology Contract
NASA has awarded the Mechanical Integrated Services and Technology contract to ATA Aerospace, Joint Venture of Albuquerque, New Mexico, for mechanical engineering and related services at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.
This is cost-plus-fixed fee, indefinite delivery-indefinite quantity small business set-aside contract with a minimum ordering value of $5 million and a maximum ordering value of $505 million. There is a 60-day phase-in period scheduled to commence on or about Sept.14 and the contract ordering period is for five-years thereafter. Individual efforts may extend beyond five years.
The contractor will provide mechanical engineering and related services, such as electrical, instrument, mission, and software for the formulation, design, development, fabrication, integration, testing, verification, and operations of spaceflight and ground system hardware and software. This includes development and validation of new technologies to enable future space and science missions to fulfill the responsibilities of the Applied Engineering and Technology Directorate at Goddard.
The principal work will be performed at Goddard and the contractor’s facility.
Release 15-187 Arctic Sea Ice Summertime Minimum Is Fourth Lowest on Record
The analysis by NASA and the NASA-supported National Snow and Ice Data Center (NSIDC) at the University of Colorado at Boulder showed the annual minimum extent was 1.70 million square miles (4.41 million square kilometers) on Sept. 11. This year’s minimum is 699,000 square miles (1.81 million square kilometers) lower than the 1981-2010 average.
Arctic sea ice cover, made of frozen seawater that floats on top of the ocean, helps regulate the planet’s temperature by reflecting solar energy back to space. The sea ice cap grows and shrinks cyclically with the seasons. Its minimum summertime extent, which occurs at the end of the melt season, has been decreasing since the late 1970s in response to warming temperatures.
In some recent years, low sea-ice minimum extent has been at least in part exacerbated by meteorological factors, but that was not the case this year.
“This year is the fourth lowest, and yet we haven’t seen any major weather event or persistent weather pattern in the Arctic this summer that helped push the extent lower as often happens,” said Walt Meier, a sea ice scientist with NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “It was a bit warmer in some areas than last year, but it was cooler in other places, too.”
In contrast, the lowest year on record, 2012, saw a powerful August cyclone that fractured the ice cover, accelerating its decline.
The sea ice decline has accelerated since 1996. The 10 lowest minimum extents in the satellite record have occurred in the last 11 years. The 2014 minimum was 1.94 million square miles (5.03 million square kilometers), the seventh lowest on record. Although the 2015 minimum appears to have been reached, there is a chance that changing winds or late-season melt could reduce the Arctic extent even further in the next few days.
“The ice cover becomes less and less resilient, and it doesn’t take as much to melt it as it used to,” Meier said. “The sea ice cap, which used to be a solid sheet of ice, now is fragmented into smaller floes that are more exposed to warm ocean waters. In the past, Arctic sea ice was like a fortress. The ocean could only attack it from the sides. Now it’s like the invaders have tunneled in from underneath and the ice pack melts from within.”
Some analyses have hinted the Arctic’s multiyear sea ice, the oldest and thickest ice that survives the summer melt season, appeared to have recuperated partially after the 2012 record low. But according to Joey Comiso, a sea ice scientist at Goddard, the recovery flattened last winter and will likely reverse after this melt season.
“The thicker ice will likely continue to decline,” Comiso said. “There might be some recoveries during some years, especially when the winter is unusually cold, but it is expected to go down again because the surface temperature in the region continues to increase.”
This year, the Arctic sea ice cover experienced relatively slow rates of melt in June, which is the month the Arctic receives the most solar energy. However, the rate of ice loss picked up during July, when the sun is still strong. Faster than normal ice loss rates continued through August, a transition month when ice loss typically begins to slow. A big “hole” appeared in August in the ice pack in the Beaufort and Chukchi seas, north of Alaska, when thinner seasonal ice surrounded by thicker, older ice melted. The huge opening allowed for the ocean to absorb more solar energy, accelerating the melt.
It’s unclear whether this year’s strong El Niño event, which is a naturally occurring phenomenon that typically occurs every two to seven years where the surface water of the eastern equatorial Pacific Ocean warms, has had any impact on the Arctic sea ice minimum extent.
“Historically, the Arctic had a thicker, more rigid sea ice that covered more of the Arctic basin, so it was difficult to tell whether El Niño had any effect on it,” said Richard Cullather, a climate modeler at Goddard. “Although we haven’t been able to detect a strong El Niño impact on Arctic sea ice yet, now that the ice is thinner and more mobile, we should begin to see a larger response to atmospheric events from lower latitudes.”
In comparison, research has found a strong link between El Niño and the behavior of the sea ice cover around Antarctica. El Niño causes higher sea level pressure, warmer air temperature and warmer sea surface temperature in west Antarctica that affect sea ice distribution. This could explain why this year the growth of the Antarctic sea ice cover, which currently is headed toward its yearly maximum extent and was at much higher than normal levels throughout much of the first half of 2015, dipped below normal levels in mid-August.
Starting next week, NASA’s Operation IceBridge, an airborne survey of polar ice, will be carrying science flights over sea ice in the Arctic, to help validate satellite readings and provide insight into the impact of the summer melt season on land and sea ice.
NASA uses the vantage point of space to increase our understanding of our home planet, improve lives, and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.
Release 15-34 NASA's LRO Discovers Earth's Pull is 'Massaging' our Moon
Earth's gravity has influenced the orientation of thousands of faults that form in the lunar surface as the moon shrinks, according to new results from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft.
In August, 2010, researchers using images from LRO's Narrow Angle Camera (NAC) reported the discovery of 14 cliffs known as "lobate scarps" on the moon's surface, in addition to about 70 previously known from the limited high-resolution Apollo Panoramic Camera photographs. Due largely to their random distribution across the surface, the science team concluded that the moon is shrinking.
These small faults are typically less than 6.2 miles (10 kilometers) long and only tens of yards or meters high. They are most likely formed by global contraction resulting from cooling of the moon's still hot interior. As the interior cools and portions of the liquid outer core solidify, the volume decreases; thus the moon shrinks and the solid crust buckles.
Now, after more than six years in orbit, the Lunar Reconnaissance Orbiter Camera (LROC) has imaged nearly three-fourths of the lunar surface at high resolution, allowing the discovery of over 3,000 more of these features. These globally distributed faults have emerged as the most common tectonic landform on the moon. An analysis of the orientations of these small scarps yielded a surprising result: the faults created as the moon shrinks are being influenced by an unexpected source—gravitational tidal forces from Earth.
Global contraction alone should generate an array of thrust faults with no particular pattern in the orientations of the faults, because the contracting forces have equal magnitude in all directions. "This is not what we found," says Smithsonian senior scientist Thomas Watters of the National Air and Space Museum in Washington. "There is a pattern in the orientations of the thousands of faults and it suggests something else is influencing their formation, something that's also acting on a global scale -- 'massaging' and realigning them." Watters is lead author of the paper describing this research published in the October issue of the journal Geology.
The other forces acting on the moon come not from its interior, but from Earth. These are tidal forces. When the tidal forces are superimposed on the global contraction, the combined stresses should cause predictable orientations of the fault scarps from region to region. "The agreement between the mapped fault orientations and the fault orientations predicted by the modeled tidal and contractional forces is pretty striking," says Watters.
"The discovery of so many previously undetected tectonic features as our LROC high-resolution image coverage continues to grow is truly remarkable," said Mark Robinson of Arizona State University, coauthor and LROC principal investigator. "Early on in the mission we suspected that tidal forces played a role in the formation of tectonic features, but we did not have enough coverage to make any conclusive statements. Now that we have NAC images with appropriate lighting for more than half of the moon, structural patterns are starting to come into focus."
The fault scarps are very young – so young that they are likely still actively forming today. The team's modeling shows that the peak stresses are reached when the moon is farthest from Earth in its orbit (at apogee). If the faults are still active, the occurrence of shallow moonquakes related to slip events on the faults may be most frequent when the moon is at apogee. This hypothesis can be tested with a long-lived lunar seismic network.
"With LRO we've been able to study the moon globally in detail not yet possible with any other body in the solar system beyond Earth, and the LRO data set enables us to tease out subtle but important processes that would otherwise remain hidden," said John Keller, LRO Project Scientist at NASA's Goddard Space Flight Center, Greenbelt, Maryland.
Launched on June 18, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the moon. LRO is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland, under the Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville for the Science Mission Directorate at NASA Headquarters in Washington, DC.
Release 15-188 Cassini Finds Global Ocean in Saturn's Moon Enceladus
A global ocean lies beneath the icy crust of Saturn's geologically active moon Enceladus, according to new research using data from NASA's Cassini mission.
Researchers found the magnitude of the moon's very slight wobble, as it orbits Saturn, can only be accounted for if its outer ice shell is not frozen solid to its interior, meaning a global ocean must be present.
The finding implies the fine spray of water vapor, icy particles and simple organic molecules Cassini has observed coming from fractures near the moon's south pole is being fed by this vast liquid water reservoir. The research is presented in a paper published online this week in the journal Icarus.
Previous analysis of Cassini data suggested the presence of a lens-shaped body of water, or sea, underlying the moon's south polar region. However, gravity data collected during the spacecraft's several close passes over the south polar region lent support to the possibility the sea might be global. The new results -- derived using an independent line of evidence based on Cassini's images -- confirm this to be the case.
"This was a hard problem that required years of observations, and calculations involving a diverse collection of disciplines, but we are confident we finally got it right," said Peter Thomas, a Cassini imaging team member at Cornell University, Ithaca, New York, and lead author of the paper.
Cassini scientists analyzed more than seven years' worth of images of Enceladus taken by the spacecraft, which has been orbiting Saturn since mid-2004. They carefully mapped the positions of features on Enceladus -- mostly craters -- across hundreds of images, in order to measure changes in the moon's rotation with extreme precision.
As a result, they found Enceladus has a tiny, but measurable wobble as it orbits Saturn. Because the icy moon is not perfectly spherical -- and because it goes slightly faster and slower during different portions of its orbit around Saturn -- the giant planet subtly rocks Enceladus back and forth as it rotates.
The team plugged their measurement of the wobble, called a libration, into different models for how Enceladus might be arranged on the inside, including ones in which the moon was frozen from surface to core.
"If the surface and core were rigidly connected, the core would provide so much dead weight the wobble would be far smaller than we observe it to be," said Matthew Tiscareno, a Cassini participating scientist at the SETI Institute, Mountain View, California, and a co-author of the paper. "This proves that there must be a global layer of liquid separating the surface from the core," he said.
The mechanisms that might have prevented Enceladus' ocean from freezing remain a mystery. Thomas and his colleagues suggest a few ideas for future study that might help resolve the question, including the surprising possibility that tidal forces due to Saturn's gravity could be generating much more heat within Enceladus than previously thought.
"This is a major step beyond what we understood about this moon before, and it demonstrates the kind of deep-dive discoveries we can make with long-lived orbiter missions to other planets," said co-author Carolyn Porco, Cassini imaging team lead at Space Science Institute (SSI), Boulder, Colorado, and visiting scholar at the University of California, Berkeley. "Cassini has been exemplary in this regard."
The unfolding story of Enceladus has been one of the great triumphs of Cassini's long mission at Saturn. Scientists first detected signs of the moon's icy plume in early 2005, and followed up with a series of discoveries about the material gushing from warm fractures near its south pole. They announced strong evidence for a regional sea in 2014, and more recently, in 2015, they shared results that suggest hydrothermal activity is taking place on the ocean floor.
Cassini is scheduled to make a close flyby of Enceladus on Oct. 28, in the mission's deepest-ever dive through the moon's active plume of icy material. The spacecraft will pass a mere 30 miles (49 kilometers) above the moon's surface.
The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the mission for the agency's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena, California. The Cassini imaging operations center is based at Space Science Institute.
Release C15-039 NASA Awards JSC Administrative Support Services II Contract
NASA has awarded AWD Management Services, Inc., of Lawrenceville, Georgia, a five-year contract to provide administrative and secretarial support services at NASA's Johnson Space Center (JSC) in Houston.
The JSC Administrative Support Services II (JASS II) contract provides administrative and secretarial support to organizations fulfilling Johnson’s missions and objectives.
The contract is valued at $73 million, with a period of performance from Nov. 1, through May 31, 2020. The performance-based contract is indefinite delivery/indefinite quantity, with specific tasks and the time to perform them to be issued on individual delivery orders.
Work under the contract will be performed at the Johnson main campus, the Sonny Carter Training Facility and Ellington Field in Houston, the White Sands Test Facility near Las Cruces, New Mexico, and other NASA operating locations or other alternate work spaces that may be determined subsequent to contract award.
