Wednesday, March 30, 2011

NASA Stardust Spacecraft Officially Ends Operations

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NASA Stardust Spacecraft
NASA's Stardust spacecraft sent its last transmission to Earth at 4:33 p.m. PDT (7:33 p.m. EDT) Thursday, March 24, shortly after depleting fuel and ceasing operations. During a 12-year period, the venerable spacecraft collected and returned comet material to Earth and was reused after the end of its prime mission in 2006 to observe and study another comet during February 2011.

The Stardust team performed the burn to depletion because the comet hunter was literally running on fumes. The depletion maneuver command was sent from the Stardust-NExT mission control area at Lockheed Martin Space Systems in Denver. The operation was designed to fire Stardust's rockets until no fuel remained in the tank or fuel lines. The spacecraft sent acknowledgment of its last command from approximately 312 million kilometers (194 million miles) away in space.

"This is the end of the spacecraft's operations, but really just the beginnings of what this spacecraft's accomplishments will give to planetary science," said Lindley Johnson, Stardust-NExT and Discovery program executive at NASA Headquarters in Washington. "The treasure-trove of science data and engineering information collected and returned by Stardust is invaluable for planning future deep space planetary missions."

After completion of the burn, mission personnel began comparing the computed amount of fuel consumed during the engine firing with the anticipated amount based on consumption models. The models are required to track fuel levels, because there are no fully reliable fuel gauges for spacecraft in the weightless environment of space. Mission planners use approximate fuel usage by reviewing the history of the vehicle's flight, how many times and how long its rocket motors fired.

"Stardust's motors burned for 146 seconds," said Allan Cheuvront, Lockheed Martin Space Systems Company program manager for Stardust-NExT in Denver. "We'll crunch the numbers and see how close the reality matches up with our projections. That will be a great data set to have in our back pocket when we plan for future missions."

Launched Feb. 7, 1999, Stardust flew past the asteroid named Annefrank and traveled halfway to Jupiter to collect the particle samples from the comet Wild 2. The spacecraft returned to Earth's vicinity to drop off a sample return capsule eagerly awaited by comet scientists.

NASA re-tasked the spacecraft as Stardust-NExT to perform a bonus mission and fly past comet Tempel 1, which was struck by the Deep Impact mission in 2005. The mission collected images and other scientific data to compare with images of that comet collected by the Deep Impact mission in 2005. Stardust traveled approximately 21 million kilometers (13 million miles) around the sun in the weeks after the successful Tempel 1 flyby. The Stardust-NExT mission met all mission goals, and the spacecraft was extremely successful during both missions. From launch until final rocket engine burn, Stardust travelled approximately 5.69 billion kilometers (3.54 billion miles).

After the mileage logged in space, the Stardust team knew the end was near for the spacecraft. With its fuel tank empty and final radio transmission concluded, history's most traveled comet hunter will move from NASA's active mission roster to retired.

"This kind of feels like the end of one of those old western movies where you watch the hero ride his horse towards the distant setting sun -- and then the credits begin to roll," said Stardust-NExT project manager Tim Larson from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Only there's no setting sun in space."

Stardust and Stardust-NExT missions were managed by JPL for NASA's Science Mission Directorate in Washington. The missions were part of the Discovery Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Joe Veverka of Cornell University was the Stardust-NExT principal investigator. Don Brownlee of the University of Washington in Seattle was the Stardust principal investigator. Lockheed Martin Space Systems built the spacecraft and managed day-to-day mission operations.

Tuesday, March 29, 2011

Work Stopped on Alternative Cameras for Mars Rover

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Work Stopped on Alternative Cameras for Mars Rover
The NASA rover to be launched to Mars this year will carry the Mast Camera (Mastcam) instrument already on the vehicle, providing the capability to meet the mission's science goals.

Work has stopped on an alternative version of the instrument, with a pair of zoom-lens cameras, which would have provided additional capabilities for improved three-dimensional video. The installed Mastcam on the Mars Science Laboratory mission's Curiosity rover uses two fixed-focal-length cameras: a telephoto for one eye and wider angle for the other. Malin Space Science Systems, San Diego, built the Mastcam and was funded by NASA last year to see whether a zoom version could be developed in time for testing on Curiosity.

"With the Mastcam that was installed last year and the rover's other instruments, Curiosity can accomplish its ambitious research goals," said Mars Science Laboratory Project Scientist John Grotzinger, of the California Institute of Technology, Pasadena. "Malin Space Science Systems has provided excellent, unprecedented science cameras for this mission. The possibility for a zoom-camera upgrade was very much worth pursuing, but time became too short for the levels of testing that would be needed for them to confidently replace the existing cameras. We applaud Malin Space Science Systems for their tremendous effort to deliver the zooms, and also the Mars Science Laboratory Project's investment in supporting this effort."

Malin Space Science Systems has also provided the Mars Hand Lens Imager and the Mars Descent Imager instruments on Curiosity. The company will continue to pursue development of the zoom system, both to prove out the design and to make the hardware available for possible use on future missions.

"While Curiosity won't benefit from the 3D motion imaging that the zooms enable, I'm certain that this technology will play an important role in future missions," said Mastcam Co-Investigator James Cameron. "In the meantime, we're certainly going to make the most of our cameras that are working so well on Curiosity right now."

Mastcam Principal Investigator Michael Malin said, "Although we are very disappointed that the zoom cameras will not fly, we expect the fixed-focal-length cameras to achieve all of the primary science objectives of the Mastcam investigation."

The rover and other parts of the Mars Science Laboratory spacecraft are in testing at NASA's Jet Propulsion Laboratory, Pasadena, Calif., which manages the project for the NASA Science Mission Directorate, Washington. The spacecraft will be delivered to NASA Kennedy Space Center in Florida in coming months for launch late this year. In August 2012, Curiosity will land on Mars for a two-year mission to examine whether conditions in the landing area have been favorable for microbial life and for preserving evidence about whether life has existed there.

Monday, March 28, 2011

Payload Installation Set to Wrap Up Saturday Morning

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NASA's Kennedy Space Center
Launch Pad 39A crews at NASA's Kennedy Space Center in Florida briefly delayed installing space shuttle Endeavour's STS-134 payload into its cargo bay today to evaluate the alignment of the Alpha Magnetic Spectrometer's remotely operated electrical umbilical, which provides heating and avionics power to the experiment. Installation now is expected to be completed Saturday morning.

During the 14-day mission to the International Space Station, Endeavour's six astronauts will deliver the Alpha Magnetic Spectrometer-2, a particle physics detector designed to search for various types of unusual matter by measuring cosmic rays and the Express Logistics Carrier-3, a platform that carries spare parts that will sustain station operations once the shuttles are retired later this year.

At NASA's Johnson Space Center, STS-134 Mission Specialists Michael Fincke and Greg Chamitoff are rehearsing techniques for the mission's fourth and final spacewalk today in the Neutral Buoyancy Laboratory.

Launch of Endeavour on the STS-134 mission to the International Space Station is targeted for 7:48 p.m. EDT April 19.

Friday, March 25, 2011

NASA's Successful 'Can Crush' Will Aid Heavy-Lift Rocket Design

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NASA's Successful 'Can Crush'
On March 23, NASA put the squeeze on a large rocket test section. Results from this structural strength test at NASA's Marshall Space Flight Center in Huntsville, Ala., will help future heavy-lift launch vehicles weigh less and reduce development costs.

This trailblazing project is examining the safety margins needed in the design of future, large launch vehicle structures. Test results will be used to develop and validate structural analysis models and generate new "shell-buckling knockdown factors" -- complex engineering design standards essential to launch vehicle design.

"This type of research is critical to NASA developing a new heavy-lift vehicle," said NASA Administrator Charlie Bolden. "The Authorization Act of 2010 gave us direction to take the nation beyond low-Earth orbit, but it is the work of our dedicated team of engineers and researchers that will make future NASA exploration missions a reality."

The aerospace industry's shell buckling knockdown factors date back to Apollo-era studies when current materials, manufacturing processes and high-fidelity computer modeling did not exist. These new analyses will update essential design factors and calculations that are a significant performance and safety driver in designing large structures like the main fuel tank of a future heavy-lift launch vehicle.

During the test, a massive 27.5-foot-diameter and 20-foot-tall aluminum-lithium test cylinder received almost one million pounds of force until it failed. More than 800 sensors measured strain and local deformations. In addition, advanced optical measurement techniques were used to monitor tiny deformations over the entire outer surface of the test article.

Wednesday, March 23, 2011

NASA Dryden Flies New Supersonic Shockwave Probes

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NASA Dryden Flies New Supersonic Shockwave Probes
NASA’s Dryden Flight Research Center is flight testing two new supersonic shockwave probes to determine their viability as research tools.

The probes were designed by Eagle Aeronautics of Hampton, Va., under a NASA Research Announcement, and manufactured by Triumph Aerospace Systems of Newport News, Va. The probes were first tested in a wind tunnel at NASA's Langley Research Center, also in Hampton.

The new probes are being flown on NASA Dryden's F-15B research test bed aircraft.

Supersonic flight over land is severely restricted in the United States and elsewhere because the sonic booms created by the shock waves propagating from supersonic aircraft are an annoyance to many and can damage private property.

Sonic boom researchers hope the Eagle Aero probes will aid their understanding of supersonic shockwaves. The ultimate goal of NASA's sonic boom research is to find ways to control the shockwaves and lessen the noise, so that it may be possible for supersonic flight to become more routine.NASA Dryden Flies New Supersonic Shockwave Probes

"Using these probes can be a real benefit in understanding and modeling the generation of shock waves and their associated sonic booms," said Dryden research engineer Dan Banks. "They could allow us to accurately define the near-instantaneous flight conditions of the aircraft being probed, while defining that airplane's flow field. At the same time, the probes provide flight condition data on the host aircraft," Banks said.

The primary objective of the flight series is to determine the feasibility of using the Eagle probes for air-to-air shockwave probing. Additional objectives include determining the durability and robustness of the probes in flight, their sensitivity to flight conditions, and the accuracy of the software.

During the initial flight test phase, the probes are attached to an adapter that hangs on the aircraft's centerline instrumented pylon, or CLIP. A large splitter plate separates the CLIP from the F-15B. This helps protect to the aircraft in the unlikely event of flutter, or damaging vibration, that might cause the probes to break off the CLIP.

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Juno Marches On

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Juno Marches On
NASA's Juno spacecraft has completed its thermal vacuum chamber testing. The two-week-long test, which concluded on March 13, 2011, is the longest the spacecraft will undergo prior to launch.

In the image, a technician is attaching the lifting equipment in preparation for hoisting the 1,588-kilogram (3,500-pound) spacecraft out of the chamber. Prominent in the photo is one of three large, black, square solar array simulators, which reproduced the thermal properties of Juno's large solar arrays.

The actual solar arrays Juno will use to power the spacecraft during its voyage to, and its exploration of, Jupiter have already been shipped to NASA's Kennedy Space Center in Florida. The main body of the Juno spacecraft, including its suite of science instruments, is scheduled to ship to Kennedy in early April, where it will undergo final preparations and launch.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute at San Antonio. The Juno mission is part of the New Frontiers Program managed at NASA's Marshall Space Flight Center in Huntsville, Ala. Lockheed Martin Space Systems, Denver, is building the spacecraft. The Italian Space Agency in Rome is contributing an infrared spectrometer instrument and a portion of the radio science experiment. JPL is a division of the California Institute of Technology in Pasadena.

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Monday, March 21, 2011

Observing Clouds for NASA Becomes a Class Tradition

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Observing Clouds for NASA Becomes a Class Tradition
Attending homecoming games, purchasing class rings, and wearing school colors are a few common traditions students pass down. A not-so-common class tradition? Validating NASA satellites.

For over 10 years, Gary Popiolkowski's seventh grade students at Chartiers-Houston Jr./Sr. High School in Houston, Pa. have carried on the tradition of sending cloud observations to NASA to help scientists make sure satellites are identifying clouds correctly

Popiolkowski's seventh graders are participants in Students' Cloud Observations On-Line (S'COOL), a program based out of NASA's Langley Research Center in Hampton, Va., that allows students from around the world to coordinate their observations with the time a NASA satellite will be observing clouds over their school.

"After doing this for so many years, my students have really bought into being diligent observers and pass that tradition on from year to year," says Popiolkowski.

So diligent that S'COOL recently named this class the top observers for the program, completing 63 observations that match a satellite overpass during a one-month period.

"Gary's class is achieving really remarkable feats," says Lin Chambers, a research scientist at NASA Langley who runs the S'COOL program. "Given that there are four opportunities in a 24-hour period, some of which are in the middle of the night, they observed for more than half of them."

The four satellites students can use to complete cloud observations are Terra, which usually passes over a given area in the morning, and Aqua, CloudSat and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations), which generally come by in the afternoon.

Popiolkowski explains that students voluntarily record cloud observations after school in the evenings, and they also take turns signing up to observe clouds over the weekend.
"Students have to make their observations within 15 minutes of a satellite overpass, because clouds change on the timescale of minutes," explains Chambers.

According to Popiolkowski, the quick changes in clouds and the process of cloud formation are some of the local standards of learning with which the S'COOL program aligns.

"S'COOL also reinforces information on the water cycle, forecasting, and how scientists use data and dichotomous keys," says Popiolkowski. One of those keys is a tool on the S'COOL site developed to help students classify clouds when they are making their observations. Once students have identified the clouds in their area, they upload their data to the S'COOL website.

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Friday, March 18, 2011

NASA Makes Use of Historic Test Site for New Robotic Lander Prototype Tests

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Today, engineers at NASA's Marshall Space Flight Center in Huntsville, Ala., began the first phase of integrated system tests on a new robotic lander prototype at Redstone Test Center’s propulsion test facility on the U.S. Army Redstone Arsenal, also in Huntsville. These tests will aid in the design and development of a new generation of small, smart, versatile robotic landers capable of performing science and exploration research on the surface of the moon or other airless bodies, including near-Earth asteroids.

This initial test phase, or strapdown testing, allows the engineering team to fully check out the integrated lander prototype before moving to more complex free flight tests. The team secures, or straps down, the prototype during hot fire tests to validate the propulsion system's response to the flight guidance, navigation and control algorithms and flight software prior to autonomous free flight testing

"Moving the robotic lander tests to the Redstone Test Center facility is a good example of intergovernmental collaboration at its best," said Larry Hill, Robotic Lunar Lander Development Project Manager Test Director, at the Marshall Center. "Engineers and technicians from NASA, the Army and our Huntsville-based support contractor, Teledyne Brown Engineering, have worked tirelessly over the last month to modify the historic test facility formerly used for missile testing to accommodate NASA's lander test in record time, saving NASA time and money."

"Our team has been on a record paced design and development schedule to deliver the robotic lander prototype to the test site," said Julie Bassler, Robotic Lunar Lander Development Project Manager. "We have succeeded in designing, building and testing this new lander prototype in a short 17 months with an in-house NASA Marshall team in collaboration with the our partners" -- Johns Hopkins Applied Physics Laboratory of Laurel, Md., and the Von Braun Center for Science and Innovation in Huntsville.

The flight test program includes three phases of testing culminating in free flight testing for periods up to sixty seconds scheduled for summer 2011. The prototype provides a platform to develop and test algorithms, sensors, avionics, software, landing legs, and integrated system elements to support autonomous landings on airless bodies, where aero-braking and parachutes are not options. The test program furthers NASA’s capability to conduct science and exploration activities on airless bodies in the solar system.

Development and integration of the lander prototype is a cooperative endeavor led by the Robotic Lunar Lander Development Project at the Marshall Center, Johns Hopkins Applied Physics Laboratory and the Von Braun Center for Science and Innovation, which includes the Science Applications International Corporation, Dynetics Corp., Teledyne Brown Engineering Inc., and Millennium Engineering and Integration Company, all of Huntsville.


Thursday, March 17, 2011

Japan Quake May Have Shortened Earth Days, Moved Axis

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Japan Quake May Have Shortened Earth Days, Moved Axis
The March 11, magnitude 9.0 earthquake in Japan may have shortened the length of each Earth day and shifted its axis. But don't worry—you won't notice the difference.

Using a United States Geological Survey estimate for how the fault responsible for the earthquake slipped, research scientist Richard Gross of NASA's Jet Propulsion Laboratory, Pasadena, Calif., applied a complex model to perform a preliminary theoretical calculation of how the Japan earthquake—the fifth largest since 1900—affected Earth's rotation. His calculations indicate that by changing the distribution of Earth's mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).

The calculations also show the Japan quake should have shifted the position of Earth's figure axis (the axis about which Earth's mass is balanced) by about 17 centimeters (6.5 inches), towards 133 degrees east longitude. Earth's figure axis should not be confused with its north-south axis; they are offset by about 10 meters (about 33 feet). This shift in Earth's figure axis will cause Earth to wobble a bit differently as it rotates, but it will not cause a shift of Earth's axis in space—only external forces such as the gravitational attraction of the sun, moon and planets can do that.

Both calculations will likely change as data on the quake are further refined.
In comparison, following last year's magnitude 8.8 earthquake in Chile, Gross estimated the Chile quake should have shortened the length of day by about 1.26 microseconds and shifted Earth's figure axis by about 8 centimeters (3 inches). A similar calculation performed after the 2004 magnitude 9.1 Sumatran earthquake revealed it should have shortened the length of day by 6.8 microseconds and shifted Earth's figure axis by about 7 centimeters, or 2.76 inches. How an individual earthquake affects Earth's rotation depends on its size (magnitude), location and the details of how the fault slipped.

Gross said that, in theory, anything that redistributes Earth's mass will change Earth's rotation.

"Earth's rotation changes all the time as a result of not only earthquakes, but also the much larger effects of changes in atmospheric winds and oceanic currents," he said. "Over the course of a year, the length of the day increases and decreases by about a millisecond, or about 550 times larger than the change caused by the Japanese earthquake. The position of Earth's figure axis also changes all the time, by about 1 meter (3.3 feet) over the course of a year, or about six times more than the change that should have been caused by the Japan quake."

Gross said that while we can measure the effects of the atmosphere and ocean on Earth's rotation, the effects of earthquakes, at least up until now, have been too small to measure. The computed change in the length of day caused by earthquakes is much smaller than the accuracy with which scientists can currently measure changes in the length of the day. However, since the position of the figure axis can be measured to an accuracy of about 5 centimeters (2 inches), the estimated 17-centimeter shift in the figure axis from the Japan quake may actually be large enough to observe if scientists can adequately remove the larger effects of the atmosphere and ocean from the Earth rotation measurements. He and other scientists will be investigating this as more data become available.


Wednesday, March 16, 2011

NASA Satellite Sees Area Affected by Japan Tsunami

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Area Affected by Japan Tsunami
A new before-and-after image pair from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft shows a region of Japan's northeastern coast, northeast of the city of Sendai, which was affected by the March 11, 2011 tsunami.

The images show the coastal cities of Ofunato and Kesennuma, located about 90 kilometers (55 miles) northeast of Sendai. Ofunato has a population of about 42,000, while the population of Kesennuma is about 73,000. Areas covered by vegetation are shown in red, while cities and unvegetated areas are shown in shades of blue-gray. The image on the left was acquired on March 14, 2011; the image on the right was acquired in August 2008. When compared closely, vegetation is no longer visible in many coastal areas in the new image, particularly around Kesennuma. Scientists believe this is most likely due to the effects of the tsunami.

The images show an area located at 39.4 degrees north latitude, 141.9 degrees east longitude, and cover an area of 28 by 46 kilometers (17 by 27 miles).

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Monday, March 14, 2011

Speed Demon Creates a Shock

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Speed Demon Creates a Shock
Just as some drivers obey the speed limit while others treat every road as if it were the Autobahn, some stars move through space faster than others. NASA's Wide-field Infrared Survey Explorer, or WISE, captured this image of the star Alpha Camelopardalis, or Alpha Cam, in astronomer-speak, speeding through the sky like a motorcyclist zipping through rush-hour traffic. The supergiant star Alpha Cam is the bright star in the middle of this image, surrounded on one side by an arc-shaped cloud of dust and gas -- a bow shock -- which is colored red in this infrared view.

Such fast-moving stars are called runaway stars. The distance and speed of Alpha Cam is somewhat uncertain. It is probably somewhere between 1,600 and 6,900 light-years away and moving at an astonishing rate of somewhere between 680 and 4,200 kilometers per second (between 1.5 and 9.4 million mph). It turns out that WISE is particularly adept at imaging bow shocks from runaway stars. Previous examples can be seen around Zeta Ophiuchi , AE Aurigae, and Menkhib. But Alpha Cam revs things up into a different gear. To put its speed into perspective, if Alpha Cam were a car driving across the United States at 4,200 kilometers per second, it would take less than one second to travel from San Francisco to New York City!

Astronomers believe runaway stars are set into motion either through the supernova explosion of a companion star or through gravitational interactions with other stars in a cluster. Because Alpha Cam is a supergiant star, it gives off a very strong wind. The speed of the wind is boosted in the forward direction the star is moving in space. When this fast-moving wind slams into the slower-moving interstellar material, a bow shock is created, similar to the wake in front of the bow of a ship in water. The stellar wind compresses the interstellar gas and dust, causing it to heat up and glow in infrared. Alpha Cam's bow shock cannot be seen in visible light, but WISE's infrared detectors show us the graceful arc of heated gas and dust around the star.

JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

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Friday, March 11, 2011

NASA Finds Polar Ice Adding More To Rising Seas

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NASA Finds Polar Ice Adding More To Rising Seas
The Greenland and Antarctic ice sheets are losing mass at an accelerating pace, according to a new NASA-funded satellite study. The findings of the study -- the longest to date of changes in polar ice sheet mass -- suggest these ice sheets are overtaking ice loss from Earth's mountain glaciers and ice caps to become the dominant contributor to global sea level rise, much sooner than model forecasts have predicted.

The nearly 20-year study reveals that in 2006, a year in which comparable results for mass loss in mountain glaciers and ice caps are available from a separate study conducted using other methods, the Greenland and Antarctic ice sheets lost a combined mass of 475 gigatonnes a year on average. That's enough to raise global sea level by an average of 1.3 millimeters (.05 inches) a year. (A gigatonne is one billion metric tons, or more than 2.2 trillion pounds.)

The pace at which the polar ice sheets are losing mass was found to be accelerating rapidly. Each year over the course of the study, the two ice sheets lost a combined average of 36.3 gigatonnes more than they did the year before. In comparison, the 2006 study of mountain glaciers and ice caps estimated their loss at 402 gigatonnes a year on average, with a year-over-year acceleration rate three times smaller than that of the ice sheets.

"That ice sheets will dominate future sea level rise is not surprising -- they hold a lot more ice mass than mountain glaciers," said lead author Eric Rignot, jointly of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of California, Irvine. "What is surprising is this increased contribution by the ice sheets is already happening. If present trends continue, sea level is likely to be significantly higher than levels projected by the United Nations Intergovernmental Panel on Climate Change in 2007. Our study helps reduce uncertainties in near-term projections of sea level rise."

Rignot's team combined nearly two decades (1992-2009) of monthly satellite measurements with advanced regional atmospheric climate model data to examine changes in ice sheet mass and trends in acceleration of ice loss.

The study compared two independent measurement techniques. The first characterized the difference between two sets of data: interferometric synthetic aperture radar data from European, Canadian and Japanese satellites and radio echo soundings, which were used to measure ice exiting the ice sheets; and regional atmospheric climate model data from Utrecht University, The Netherlands, used to quantify ice being added to the ice sheets. The other technique used eight years of data from the NASA/German Aerospace Center's Gravity Recovery and Climate Experiment (Grace) satellites, which track minute changes in Earth's gravity field due to changes in Earth's mass distribution, including ice movement.

The team reconciled the differences between techniques and found them to be in agreement, both for total amount and rate of mass loss, over their data sets' eight-year overlapping period. This validated the data sets, establishing a consistent record of ice mass changes since 1992.

The team found that for each year over the 18-year study, the Greenland ice sheet lost mass faster than it did the year before, by an average of 21.9 gigatonnes a year. In Antarctica, the year-over-year speedup in ice mass lost averaged 14.5 gigatonnes.

"These are two totally independent techniques, so it is a major achievement that the results agree so well," said co-author Isabella Velicogna, also jointly with JPL and UC Irvine. "It demonstrates the tremendous progress that's being made in estimating how much ice the ice sheets are gaining and losing, and in analyzing Grace's time-variable gravity data."

The authors conclude that, if current ice sheet melting rates continue for the next four decades, their cumulative loss could raise sea level by 15 centimeters (5.9 inches) by 2050. When this is added to the predicted sea level contribution of 8 centimeters (3.1 inches) from glacial ice caps and 9 centimeters (3.5 inches) from ocean thermal expansion, total sea level rise could reach 32 centimeters (12.6 inches). While this provides one indication of the potential contribution ice sheets could make to sea level in the coming century, the authors caution that considerable uncertainties remain in estimating future ice loss acceleration.

Study results are published this month in Geophysical Research Letters. Other participating institutions include the Institute for Marine and Atmospheric Research, Utrecht University, The Netherlands; and the National Center for Atmospheric Research, Boulder, Colo.

JPL developed Grace and manages the mission for NASA. The University of Texas Center for Space Research in Austin has overall mission responsibility. GeoForschungsZentrum Potsdam (GFZ), Potsdam, Germany, is responsible for German mission elements.
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Tuesday, March 8, 2011

NASA Creates Glory Satellite Mishap Investigation Board

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NASA Creates Glory Satellite Mishap Investigation Board
NASA's Glory mission ended Friday after the spacecraft failed to reach orbit following its launch from Vandenberg Air Force Base in California.

NASA has begun the process of creating a Mishap Investigation Board to evaluate the cause of the failure. Telemetry indicated the fairing, a protective shell atop the satellite's Taurus XL rocket, did not separate as expected.

The launch proceeded as planned from its liftoff at 5:09 a.m. EST through the ignition of the Taurus XL's second stage. However, the fairing failure occurred during the second stage engine burn. It is likely the spacecraft fell into the South Pacific, although the exact location is not yet known.

NASA's previous launch attempt of an Earth science spacecraft, the Orbiting Carbon Observatory onboard a Taurus XL on Feb. 24, 2009, also failed to reach orbit when the fairing did not separate.

NASA's Orbiting Carbon Observatory Mishap Investigation Board reviewed launch data and the fairing separation system design, and developed a corrective action plan. The plan was implemented by Taurus XL manufacturer Orbital Sciences Corporation. In October 2010, NASA's Flight Planning Board confirmed the successful closure of the corrective actions.

The Glory Earth-observing satellite was intended to improve our understanding of how the sun and tiny atmospheric particles called aerosols affect Earth's climate.
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Monday, March 7, 2011

NASA Dryden Flies New Supersonic Shockwave Probes

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NASA Dryden Flies
NASA’s Dryden Flight Research Center is flight testing two new supersonic shockwave probes to determine their viability as research tools.

The probes were designed by Eagle Aeronautics of Hampton, Va., under a NASA Research Announcement, and manufactured by Triumph Aerospace Systems of Newport News, Va. The probes were first tested in a wind tunnel at NASA's Langley Research Center, also in Hampton.

The new probes are being flown on NASA Dryden's F-15B research test bed aircraft.

Supersonic flight over land is severely restricted in the United States and elsewhere because the sonic booms created by the shock waves propagating from supersonic aircraft are an annoyance to many and can damage private property.

Sonic boom researchers hope the Eagle Aero probes will aid their understanding of supersonic shockwaves. The ultimate goal of NASA's sonic boom research is to find ways to control the shockwaves and lessen the noise, so that it may be possible for supersonic flight to become more routine.

"Using these probes can be a real benefit in understanding and modeling the generation of shock waves and their associated sonic booms," said Dryden research engineer Dan Banks. "They could allow us to accurately define the near-instantaneous flight conditions of the aircraft being probed, while defining that airplane's flow field. At the same time, the probes provide flight condition data on the host aircraft," Banks said.

The primary objective of the flight series is to determine the feasibility of using the Eagle probes for air-to-air shockwave probing. Additional objectives include determining the durability and robustness of the probes in flight, their sensitivity to flight conditions, and the accuracy of the software.

During the initial flight test phase, the probes are attached to an adapter that hangs on the aircraft's centerline instrumented pylon, or CLIP. A large splitter plate separates the CLIP from the F-15B. This helps protect to the aircraft in the unlikely event of flutter, or damaging vibration, that might cause the probes to break off the CLIP.

NASA Dryden Flies
The two probes are mounted beside each other on the CLIP, one wedge-shaped and the other is conical. Both are designed to make very accurate measurements of supersonic airflow, improving the quality of the shockwave data engineers can glean.

If the probe combo proves robust in this series of tests, researchers could develop a follow-on series with the probes attached one at a time to the F-15B's nose so each has access to the clean airstream in front of the aircraft. Mounting such devices on the aircraft’s nose is the normal and preferred placement, which allows them access to the clean airstream ahead of the carrier aircraft.

Later test flights could include a second supersonic aircraft flying ahead of the probe-carrying F-15 to generate shockwaves for an early look at the probes’ shockwave-sensing capabilities.

Past supersonic shockwave probing efforts, such as the Lancets project flown at Dryden in 2008-2009, used a standard probe. The more streamlined Eagle Aero probes contain accurate high-response transducers that help to eliminate any lag or other errors as they measure upstream and downstream airflow conditions and can measure flow angles.

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Friday, March 4, 2011

NASA Nanosatellite Celebrates 100 Days In Space Studying Life

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NASA Nanosatellite Celebrates 100 Days
More than one hundred days ago, on Nov. 19, 2010, NASA sent a small satellite about the size of a loaf of bread on an important mission to answer astrobiology’s fundamental questions about the origin, evolution and distribution of life in the universe.

Since then, the nanosatellite, known as Organism/Organic Exposure to Orbital Stresses (O/OREOS) continues on its quest, which has taken it just about everywhere between the Arctic and Antarctic Circles more than 400 miles above Earth's surface.

O/OREOS weighs approximately 12 pounds and is NASA’s first CubeSat to demonstrate the capability to have two distinct, completely independent science experiments on a single autonomous satellite. O/OREOS is using NASA’s first propellant-less mechanism on a scientific satellite to ensure it de-orbits and burns up as it re-enters Earth’s atmosphere, less than 25 years after completing its mission. It's also the first nanosatellite to not only operate, but also conduct autonomous biological and chemical measurements, in the region of space known as the exosphere.NASA Nanosatellite Celebrates 100 Days

"The fact that we're getting consistently good science data in such a challenging environment tells us that secondary payload nanosatellites like O/OREOS can be made rugged enough to enhance our opportunities to conduct research in low Earth orbit," said Antonio Ricco, instrument scientist for O/OREOS and a researcher at NASA's Ames Research Center, Moffett Field, Calif. "This is enabling us to study organics, microorganisms, and astrobiology in the space environment in real time."

O/OREOS was a secondary payload aboard a U.S. Air Force four-stage Minotaur IV rocket launched from the Alaska Aerospace Corporation’s Kodiak Launch Complex on Kodiak Island, Alaska. After O/OREOS separated from the rocket and successfully entered low Earth orbit, it activated and began transmitting radio signals to ground control stations and spacecraft operators in the mission control center at Santa Clara University, Santa Clara, Calif. Nearly daily two-way communications with the spacecraft provided valuable information about its health, status and science data, and have given scientists the ability to fine tune the science payloads’ operating parameters.

On Dec. 3, 2010, two weeks after O/OREOS deployed, the first of three biological experiments began operating automatically within the Space Environment Survivability of Living Organisms (SESLO) payload; and was successfully completed just 24 hours later. On Feb. 18, 2011, the second part of the SESLO biological experiment began and also was successfully finished in one day. The experiment is designed to characterize the growth, activity, health and ability of microorganisms commonly found in soil and salt ponds in a dried and dormant state - Bacillus subtilis and Halorubrum chaoviatoris – to adapt to the stresses of outer space by rehydrating, or “feeding,” and growing them using dyed liquid nutrients. Scientists will compare the microbes' population density and change in color at three different times during the mission to determine how and if their behavior changes with longer exposure to radiation and weightless conditions in space.

"Days before the second part of the SESLO experiment began, a large solar flare sent radiation, including energetic protons and X-rays, hurtling towards O/OREOS and Earth, yet O/OREOS still successfully completed the experiment and got some promising results that we're now evaluating," said Ricco.

Hours after reaching orbit, O/OREOS activated its other science experiment payload, called the Space Environment Viability of Organics (SEVO), which monitors the stability and changes in four classes of biologically important organic molecules as they are exposed to space conditions, most notably sunlight completely unfiltered by Earth’s atmosphere. For the SEVO experiment, scientists selected organic molecules distributed throughout our galaxy, as well as organic “biomarkers” of life as we know it on Earth. O/OREOS houses the organic samples in “micro-environments” relevant to space and planetary conditions. The experiment exposes the organic compounds to solar ultraviolet (UV) light, visible light, trapped-particle and cosmic radiation. Scientists will determine the stability of the molecules by studying changes in UV, visible, and near-infrared light absorption.

"Using the sun as its light source, O/OREOS has made nearly 500 periodic spectral measurements of the organic materials, and 200 of those have been transmitted to us so far," said Pascale Ehrenfreund, O/OREOS project scientist at George Washington University, Washington, D.C. "We are excited to see the payload's miniature spectrometer and sample positioning systems working so well and are grateful to our operations team at Santa Clara University."

Thursday, March 3, 2011

NASA Dryden Flies New Supersonic Shockwave Probes

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NASA Dryden Flies New Supersonic Shockwave Probes
NASA’s Dryden Flight Research Center is flight testing two new supersonic shockwave probes to determine their viability as research tools.

The probes were designed by Eagle Aeronautics of Hampton, Va., under a NASA Research Announcement, and manufactured by Triumph Aerospace Systems of Newport News, Va. The probes were first tested in a wind tunnel at NASA's Langley Research Center, also in Hampton.

The new probes are being flown on NASA Dryden's F-15B research test bed aircraft.

Supersonic flight over land is severely restricted in the United States and elsewhere because the sonic booms created by the shock waves propagating from supersonic aircraft are an annoyance to many and can damage private property.

Sonic boom researchers hope the Eagle Aero probes will aid their understanding of supersonic shockwaves. The ultimate goal of NASA's sonic boom research is to find ways to control the shockwaves and lessen the noise, so that it may be possible for supersonic flight to become more routine.

"Using these probes can be a real benefit in understanding and modeling the generation of shock waves and their associated sonic booms," said Dryden research engineer Dan Banks. "They could allow us to accurately define the near-instantaneous flight conditions of the aircraft being probed, while defining that airplane's flow field. At the same time, the probes provide flight condition data on the host aircraft," Banks said.
NASA Dryden Flies New Supersonic Shockwave Probes

The primary objective of the flight series is to determine the feasibility of using the Eagle probes for air-to-air shockwave probing. Additional objectives include determining the durability and robustness of the probes in flight, their sensitivity to flight conditions, and the accuracy of the software.

During the initial flight test phase, the probes are attached to an adapter that hangs on the aircraft's centerline instrumented pylon, or CLIP. A large splitter plate separates the CLIP from the F-15B. This helps protect to the aircraft in the unlikely event of flutter, or damaging vibration, that might cause the probes to break off the CLIP.

The two probes are mounted beside each other on the CLIP, one wedge-shaped and the other is conical. Both are designed to make very accurate measurements of supersonic airflow, improving the quality of the shockwave data engineers can glean

Wednesday, March 2, 2011

Launching Balloons in Antarctica

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Launching Balloons in Antarctica
They nicknamed it the "Little Balloon That Could." Launched in December of 2010 from McMurdo Station in Antarctica, the research balloon was a test run and it bobbed lower every day like it had some kind of leak. But every day for five days it rose back up in the sky to some 112,000 feet in the air.

Down on Earth, physicist Robyn Millan was cheering it on, hoping the test launch would bode well for the success of her grand idea: launches in 2013 and 2014 of 20 such balloons to float in the circular wind patterns above the South Pole. Each balloon will help track electrons from space that get swept up in Earth's magnetic field and slide down into our atmosphere. Such electrons are an integral part of the turbulent magnetic space weather system that extends from the sun to Earth.

A professor at Dartmouth College, Millan is the principal investigator for a project called BARREL, or Balloon Array for RBSP Relativistic Electron Losses. Millan's proposal will work hand in hand with NASA's Radiation Belt Space Probes (RBSP) mission, two NASA spacecraft due to launch in 2012 to study a mysterious part of Earth's magnetic environs called the Van Allen radiation belts. The radiation belts are made up of two regions, each one a gigantic donut of protons and electrons that surrounds Earth.

"We're both looking at the loss of particles from the radiation belts," says Millan. "RBSP sits in space near the equatorial plane and looks at the particles along magnetic field lines there. These particles come into our atmosphere – following magnetic field lines to their base at the Poles – and produce X-rays. BARREL measures those X-rays. Together we can combine measurements of the same set of particles."

Figuring out what causes this rain of electrons will do more than simply improve understanding of the physics behind what drives such high-energy particles. The charged particles within the radiation belts can damage sensitive electronics on spacecraft like those used for global positioning systems and communications, and can injure humans in space. (The electrons don't make it all the way to Earth, so pose no danger to those of us on the ground.) Experiments like BARREL and RBSP help us understand the processes and mitigate those risks.

Millan began working on balloons during her graduate work at University of California, Berkeley, where she studied physics. She worked on a balloon called MAXIS that focused on electron precipitation from the magnetosphere into the ionosphere. "Then," she says, "We got this idea. They launch these huge payloads in Antarctica, but before that they send up smaller test balloons to make sure conditions are right for the big launch. And we thought – what if you could put instruments on those? So we took our payload, and miniaturized it."

She and her team, which includes scientists and students at UC Berkeley, UC Santa Cruz, and University of Washington, set about making payloads that weigh only 50 pounds for balloons that are some 90 feet in diameter. That still sounds fairly big unless you know that the typical balloons launched in Antarctica are the size of a football field and carry payloads of some 3,000 pounds. The team received funding from the National Science Foundation to fly a total of six small balloons in 2005, and shortly thereafter she learned that NASA had put out a call for experiments to support RBSP.

David Sibeck, the mission scientist for RBSP at Goddard Space Flight Center in Greenbelt, Md., recalls that Millan's project proposal was well-tailored to RBSP's goals. "One of RBSP's main challenges will be to differentiate between the hordes of theories that try to explain why the belts wax and wane over time," Sibeck says. "The RBSP spacecraft will be equipped to distinguish between different options, but Millan's balloons have an advantage in one specific area: they can measure particles that break out of the belts and make it all the way to Earth's atmosphere."