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WASHINGTON - NASA and the U.S. Department of Energy (DOE) have signed a memorandum of understanding for the implementation of the Joint Dark Energy Mission, or JDEM. The mission will feature the first space-based observatory designed specifically to understand the nature of dark energy.

Dark energy is a form of energy that pervades and dominates the universe. The mission will measure with high precision the universe's expansion rate and growth structure. Data from the mission could help scientists determine the properties of dark energy, fundamentally advancing physics and astronomy.

"Understanding the nature of dark energy is the biggest challenge in physics and astronomy today," said Jon Morse, director of astrophysics at NASA Headquarters in Washington. "JDEM will be a unique and major contributor in our quest to understand dark energy and how it has shaped the universe in which we live."

One of the most significant scientific findings in the last decade is that the expansion of the universe is accelerating. The acceleration is caused by a previously unknown dark energy that makes up approximately 70 percent of the total mass energy content of the universe. This mission has the potential to clarify the properties of this mass energy. JDEM also will provide scientists with detailed information for understanding how galaxies form and acquire their mass.

"DOE and NASA have complementary on-going research into the nature of dark energy and complementary capabilities to build JDEM, so it is wonderful that our agencies have teamed for the implementation of this mission," said Dennis Kovar, associate director of the DOE Office of Science for High Energy Physics.

In 2006, NASA and DOE jointly funded a National Research Council study by the Beyond Einstein Program Assessment Committee to assist NASA in determining the highest priority of the five proposed missions in its Beyond Einstein program. In September 2007, the committee released its report and noted that JDEM will set the standard in precisely determining the distribution of dark energy in the distant universe. The committee recommended that JDEM be the first of NASA's Beyond Einstein missions to be developed and launched. Following the committee's report, NASA and DOE agreed to proceed with JDEM.

The importance of understanding dark energy also has been emphasized in a number of other significant reports from the National Research Council, the National Science and Technology Council, and the Dark Energy Task Force.

For more information about JDEM, including the signed memorandum of understanding, visit: http://jdem.gsfc.nasa.gov

Author / Source / Credit: NASA

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NOAA has released new scientific information showing a decline in the walleye pollock biomass that has the agency recommending a cut to the pollock catch for 2009 in the eastern Bering Sea.

"Although the pollock biomass was well above average in the 1990s, our surveys show a substantial decline in recent years," said Doug DeMaster, science and research director for NOAA's Alaska Fisheries Science Center. "The stock has been closely monitored and management decisions have historically followed sound conservation principles. We anticipate lower catch limits for 2009."

A 2008 bottom trawl survey of pollock numbers was in line with last year's analysis, but another survey that combined information from acoustic measurements of pollock biomass and midwater trawl results showed lower abundance than expected. These results have prompted NOAA scientists to recommend to the North Pacific Fishery Management Council a sustainable catch of 815,000 metric tons for 2009, an 18.5 percent reduction from 2008. The new scientific information on pollock comes from major scientific surveys this season, plus catch data and oceanographic information.

The council will review and discuss NOAA's recommendation at its December meeting and make its recommendation to NOAA's Fisheries Service for the total allowable catch of pollock for 2009.

Although recent surveys show the biomass has declined, there is some optimism about the future of the stock.

"The prognosis for 2010 is for improved stock levels because 2006 was a more successful year for the hatching and survival of young pollock," said Jim Ianelli, a stock assessment scientist at the NOAA Alaska Fisheries Science Center. "The 2009 surveys will play a critical role in monitoring and in later management decisions."

The eastern Bering Sea pollock fishery is known for its strong management, conservative catch levels, near real-time reporting and high numbers of fishery observers who track catch levels and any bycatch of other marine species. The fishery uses pelagic trawls which minimize disturbance of the bottom habitat and decrease the accidental catch of other species. The most valuable part of the fishery is roe. Regulations allow no more than 40 percent of the total catch to be taken during the roe season.

NOAA scientists recently presented the draft pollock stock assessment to the North Pacific Fishery Management Council's Groundfish Plan Team, which is reviewing the assessment and compiling the report for the council. The council's scientific and statistical committee will recommend an acceptable biological catch level - a sustainable catch level - and the advisory panel will recommend a total allowable catch, which is historically lower because it takes into account other factors. After listening to committee recommendations and public input, the council will recommend a total allowable catch for pollock for 2009.

Author / Source / Credit: NOAA

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PASADENA, Calif. - NASA's Mars Reconnaissance Orbiter has revealed vast Martian glaciers of water ice under protective blankets of rocky debris at much lower latitudes than any ice previously identified on the Red Planet.

Scientists analyzed data from the spacecraft's ground-penetrating radar and report in the Nov. 21 issue of the journal Science that buried glaciers extend for dozens of miles from the edges of mountains or cliffs. A layer of rocky debris blanketing the ice may have preserved the underground glaciers as remnants from an ice sheet that covered middle latitudes during a past ice age. This discovery is similar to massive ice glaciers that have been detected under rocky coverings in Antarctica.

"Altogether, these glaciers almost certainly represent the largest reservoir of water ice on Mars that is not in the polar caps," said John W. Holt of the University of Texas at Austin, who is lead author of the report. "Just one of the features we examined is three times larger than the city of Los Angeles and up to half a mile thick. And there are many more. In addition to their scientific value, they could be a source of water to support future exploration of Mars."

Scientists have been puzzled by what are known as aprons - gently sloping areas containing rocky deposits at the bases of taller geographical features - since NASA's Viking orbiters first observed them on the Martian surface in the 1970s. One theory has been that the aprons are flows of rocky debris lubricated by a small amount ice. Now, the shallow radar instrument on the Mars Reconnaissance Orbiter has provided scientists an answer to this Martian puzzle.

"These results are the smoking gun pointing to the presence of large amounts of water ice at these latitudes," said Ali Safaeinili, a shallow radar instruments team member with NASA's Jet Propulsion Laboratory in Pasadena, Calif.

Radar echoes received by the spacecraft indicated radio waves pass through the aprons and reflect off a deeper surface below without significant loss in strength. That is expected if the apron areas are composed of thick ice under a relatively thin covering. The radar does not detect reflections from the interior of these deposits as would occur if they contained significant rock debris. The apparent velocity of radio waves passing through the apron is consistent with a composition of water ice.

Scientists developed the shallow radar instrument for the orbiter to examine these mid-latitude geographical features and layered deposits at the Martian poles. The Italian Space Agency provided the instrument.

"We developed the instrument so it could operate on this kind of terrain," said Roberto Seu, leader of the instrument science team at the University of Rome La Sapienza in Italy. "It is now a priority to observe other examples of these aprons to determine whether they are also ice."

Holt and 11 co-authors report the buried glaciers lie in the Hellas Basin region of Mars' southern hemisphere. The radar also has detected similar-appearing aprons extending from cliffs in the northern hemisphere.

"There's an even larger volume of water ice in the northern deposits," said JPL geologist Jeffrey J. Plaut, who will be publishing results about these deposits in the American Geophysical Union's Geophysical Research Letters. "The fact these features are in the same latitude bands, about 35 to 60 degrees in both hemispheres, points to a climate-driven mechanism for explaining how they got there."

The rocky debris blanket topping the glaciers apparently has protected the ice from vaporizing, which would happen if it were exposed to the atmosphere at these latitudes.

"A key question is, how did the ice get there in the first place?" said James W. Head of Brown University in Providence, R.I. "The tilt of Mars' spin axis sometimes gets much greater than it is now. Climate modeling tells us ice sheets could cover mid-latitude regions of Mars during those high-tilt periods. The buried glaciers make sense as preserved fragments from an ice age millions of years ago. On Earth, such buried glacial ice in Antarctica preserves the record of traces of ancient organisms and past climate history."

JPL manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate in Washington. For more information about the Mars Reconnaissance Orbiter, visit: http://www.nasa.gov/mro

Author / Source / Credit: NASA

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GPS-equipped aircraft in Alaska can now fly more direct, efficient routes in areas lacking radar coverage.

The FAA recently approved new procedures that allow GPS-equipped aircraft to proceed from point-to-point directly in areas of limited or no radar coverage in Alaska. This is important in a state whose far-flung population depends on air service for the delivery of goods and transportation of people.

The change also moves us forward in meeting our goal of establishing an improved Wide Area Augmentation System (WAAS)-enabled Area Navigation (RNAV) route structure throughout Alaska.

The advanced space-based WAAS system increases the accuracy and integrity of GPS for aircraft navigation. Since WAAS signals are provided from space, there is no need for FAA to install and maintain navigation equipment at an airport. RNAV routes, which can allow equipped aircraft to fly on any desired flight path, also minimize dependence on ground-based navigation.

Prior to the new procedures being implemented, aircraft with GPS couldn't fly from point to point on random RNAV routes below 45,000 feet unless they were being monitored by radar.

Now they can take advantage of the precise, performance-based navigation offered by GPS.

Author / Source / Credit: FAA

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