NASA's IceBridge Seeking New View of Changing Sea Ice

This year scientists working on NASA's Operation IceBridge, a multi-year airborne science mission to study changing ice conditions at both poles, debuted a new data product with the potential to improve Arctic sea ice forecasts.

Using new data processing techniques, IceBridge scientists were able to release an experimental quick look product before the end of the 2012 Arctic campaign. The main challenge faced when producing data for seasonal forecasts is the time needed to crunch the numbers, something that has in the past taken IceBridge scientists more than six months to do after the data was collected in the spring. This is too late to use for Arctic sea ice forecasts of the annual seasonal minimum, which takes place in September.

The new product could potentially be used in seasonal sea ice forecasts in the future. "The community is excited about it," said IceBridge science team co-lead Jackie Richter-Menge of the U.S. Army Corps of Engineers Cold Regions Research Laboratory, Hanover, N.H. "We're hoping to build on this season's momentum and interest."

Scientists have been keeping an eye on Arctic sea ice in recent years because it is changing and they want to understand what those changes might mean. Arctic sea ice grows and recedes in a seasonal pattern, with a maximum coverage in March and a minimum in September. These high and low points vary from year to year, but there is a clear trend toward smaller minimums that mean more open water in the Arctic each summer and fall. This decrease in ice is already affecting ocean and terrestrial life in the Arctic, accelerating warming in the region and leading to economic and social changes.

"Sea ice is a sensitive indicator of a changing climate," said NASA researcher Nathan Kurtz at NASA's Goddard Space Flight Center, Greenbelt, Md. It can also act as a feedback to warming in the Arctic. Because ice is much lighter in color than ocean water it has a higher albedo, meaning it reflects more sunlight than water. "A loss of sea ice can cause the Earth as a whole to warm," Kurtz said. The loss of sea ice has also been linked to shifts in weather patterns and distribution of nutrients in the ocean.

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NASA Spacecraft Reveals Recent Geological Activity on the Moon

New images from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft show the moon's crust is being stretched, forming minute valleys in a few small areas on the lunar surface. Scientists propose this geologic activity occurred less than 50 million years ago, which is considered recent compared to the moon's age of more than 4.5 billion years.

A team of researchers analyzing high-resolution images obtained by the Lunar Reconnaissance Orbiter Camera (LROC) show small, narrow trenches typically much longer than they are wide. This indicates the lunar crust is being pulled apart at these locations. These linear valleys, known as graben, form when the moon's crust stretches, breaks and drops down along two bounding faults. A handful of these graben systems have been found across the lunar surface.

"We think the moon is in a general state of global contraction because of cooling of a still hot interior," said Thomas Watters of the Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum in Washington, and lead author of a paper on this research appearing in the March issue of the journal Nature Geoscience. "The graben tell us forces acting to shrink the moon were overcome in places by forces acting to pull it apart. This means the contractional forces shrinking the moon cannot be large, or the small graben might never form."

The weak contraction suggests that the moon, unlike the terrestrial planets, did not completely melt in the very early stages of its evolution. Rather, observations support an alternative view that only the moon's exterior initially melted forming an ocean of molten rock.

In August 2010, the team used LROC images to identify physical signs of contraction on the lunar surface, in the form of lobe-shaped cliffs known as lobate scarps. The scarps are evidence the moon shrank globally in the geologically recent past and might still be shrinking today. The team saw these scarps widely distributed across the moon and concluded it was shrinking as the interior slowly cooled.

Based on the size of the scarps, it is estimated that the distance between the moon's center and its surface shrank by approximately 300 feet. The graben were an unexpected discovery and the images provide contradictory evidence that the regions of the lunar crust are also being pulled apart.

"This pulling apart tells us the moon is still active," said Richard Vondrak, LRO Project Scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "LRO gives us a detailed look at that process."

As the LRO mission progresses and coverage increases, scientists will have a better picture of how common these young graben are and what other types of tectonic features are nearby. The graben systems the team finds may help scientists refine the state of stress in the lunar crust.

"It was a big surprise when I spotted graben in the far side highlands," said co-author Mark Robinson of the School of Earth and Space Exploration at Arizona State University, principal investigator of LROC. "I immediately targeted the area for high-resolution stereo images so we could create a three-dimensional view of the graben.

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Beaming Success for Station Fans

Did you ever use a flashlight to send a Morse code message to your neighbor at night as a kid? People like to say hello using lights and it's no different for space aficionados who want to twinkle a greeting from the Earth to the International Space Station during a sighting as it passes overhead -- except that it is a whole lot more complicated.

Although the space station has been in orbit for more than a decade, the first successful flashing of a beam of light to the laboratory happened only recently. On March 3, 2012, the San Antonio Astronomical Association met to attempt to shine a signal to the station. Aboard the orbiting lab, astronaut Don Pettit was watching and waiting.

"It sounds deceptively easy," said Pettit in a related blog entry. "But like so many other tasks, it becomes much more involved in the execution than in the planning."

The ground group used a one-watt blue laser and a white spotlight to track the station as it flew overhead. Pettit worked via e-mail with the association members to run complicated engineering calculations to ensure they were accurately tracking the station. Considerations included the diameter of the light beam, the intensity of the laser, and the fact that the station is a moving target, as Pettit pointed out in another blog post on the difficulty of Earth photography from space.

"From my orbital perspective, I am sitting still and Earth is moving," said Pettit. "I sit above the grandest of all globes spinning below my feet, and watch the world speed by at an amazing eight kilometers per second [approximately 17,880 miles per hour]."

Pettit had additional complications to address to capture an image of the beam of light from the Texas fans of the space station. Even with a shutter speed of 1/1000 of a second, the camera he used on station was not fast enough to photograph the Earth below, which also is moving. To compensate for this, Pettit used precise manual tracking -- a technique of moving the camera along the same path as the object being photographed -- a skill perfected on orbit while working on Crew Earth Observations research.

While photographing the Earth may provide an entertaining pastime for the crew, there also are important research goals and benefits for those of us on the ground. It can take up to a month, according to Pettit, for astronauts to become proficient at taking this kind of planned image. The crew's photographic efforts can provide orbital perspectives of natural disasters and man-made alterations of the planet, which aid in relief and environmental efforts.

Preparing to capture the laser flash provided practice for Pettit in planning and tracking a specific Earth target. With the station circling the Earth every 90 minutes, you might think there is ample opportunity, but the circumstances of the pass had to align. Pettit and the team in San Antonio had to choose their timing carefully, selecting a "dark pass" when the station could see the ground, but those on the ground could not see the station.

"Ironically, when earthlings can see us, we cannot see them," said Pettit. "The glare from the full sun effectively turns our windows into mirrors that return our own ghostly reflection. This often plays out when friends want to flash space station from the ground as it travels overhead."

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NASA Jet Stream Study Will Light up The Night Sky

High in the sky, 60 to 65 miles above Earth's surface, winds rush through a little understood region of Earth's atmosphere at speeds of 200 to 300 miles per hour. Lower than a typical satellite's orbit, higher than where most planes fly, this upper atmosphere jet stream makes a perfect target for a particular kind of scientific experiment: the sounding rocket. Some 35 to 40 feet long, sounding rockets shoot up into the sky for short journeys of eight to ten minutes, allowing scientists to probe difficult-to-reach layers of the atmosphere.

In March, NASA will launch five such rockets in approximately five minutes to study these high-altitude winds and their intimate connection to the complicated electrical current patterns that surround Earth. First noticed in the 1960s, the winds in this jet stream shouldn't be confused with the lower jet stream located around 30,000 feet, through which passenger jets fly and which is reported in weather forecasts. This rocket experiment is designed to gain a better understanding of the high-altitude winds and help scientists better model the electromagnetic regions of space that can damage man-made satellites and disrupt communications systems. The experiment will also help explain how the effects of atmospheric disturbances in one part of the globe can be transported to other parts of the globe in a mere day or two.

"This area shows winds much larger than expected," says Miguel Larsen, a space scientist at Clemson University who is the principal investigator for these five rockets, known as the Anomalous Transport Rocket Experiment (ATREX). "We don't yet know what we're going to see, but there is definitely something unusual going on. ATREX will help us understand the big question about what is driving these fast winds."

Determining what drives these winds requires precise understanding of the way the winds move and what kind of turbulence they show. To get an idea of the task at hand, imagine mapping not just the ups and downs of ocean waves but the attendant surf, undertow, and tides, all from 60 miles away and in only 20 minutes. To accomplish this, the five sounding rockets will launch from NASA's Wallops Flight Facility in Virginia releasing a chemical tracer into the air. The chemical – a substance called trimethyl aluminum (TMA) -- forms milky, white clouds that allow those on the ground to "see" the winds in space and track them with cameras. In addition, two of the rockets will have instrumented payloads to measure pressure and temperature in the atmosphere.

The rockets will be launched on a clear night within a period of minutes, so the trails can all be seen at the same time. The trimethyl aluminum will then be released in space out over the Atlantic Ocean at altitudes from 50 to 90 miles. The cloud tracers will last for up to 20 minutes and will be visible in the mid-Atlantic region, and along the east coast of the United States from parts of South Carolina to New Jersey.

"People have launched single rockets before," says Larsen. "But the key here is that we're extending the range of measurements to many hundreds of miles. The furthest rocket will make it half way to Bermuda."

Sounding rockets are usually launched one or two at a time, so launching five at once will call for specific timing and direction to gather the required data. The rockets must be launched on a clear night between March 14 and April 3. Scientists will then use special camera equipment to track the five clouds and measure how quickly they move away from each other. They can then plug this information into equations that will describe what kind of turbulence exists in the winds.

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NASA downplays risk of asteroid strike in 2040

An asteroid discovered last year has been gaining notoriety because of a chance that it could hit Earth in 28 years, but NASA scientists say the odds are extremely remote that it will pose any danger to us.

The huge space rock, called asteroid 2011 AG5, is about 460 feet (140 meters) wide and circles the sun on a path between the orbits of Mars and Venus. Astronomers spotted it on Jan. 8, 2011, using the 60-inch Cassegrain reflector telescope on Mount Lemmon north of Tucson, Ariz.

Some projections suggest the odds of an Earth impact are 1 in 625. But the asteroid is rated a 1 on the 1-to-10 Torino Impact Hazard Scale that denotes potentially dangerous asteroids (1 is the least hazardous rating), NASA scientists say. So while there is a slight chance that asteroid 2011 AG5 could impact our planet in 2040, astronomers still need much better observations to define its orbit.

"Because of the extreme rarity of an impact by a near-Earth asteroid of this size, I fully expect we will be able to significantly reduce or rule out entirely any impact probability for the foreseeable future," Don Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.

The asteroid is expected to come near Earth in February 2023, but it will pass no closer than about 1 million miles (1.6 million kilometers) at that time. It will be in the area again in 2028, but it won't come closer than about 10.4 million miles (16.7 million kilometers) from our planet.

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NASA gives update on mission to moon

NASA announced Monday that it is entering a new stage of a mission intended to place a pair of probes around Earth’s nearest neighbor and only satellite.

NASA officials said Monday mission controllers are preparing for the twin spaceships, named Grail-A and Grail-B, to enter the moon’s orbit on New Year’s Eve. The pair of probes are tasked with measuring the uneven gravity field of the moon and determine what lies beneath — straight down to the core.

NASA’s twin lunar Gravity Recovery and Interior Laboratory (GRAIL) probes were launched from Cape Canaveral Air Force Station on September 10, 2011. GRAIL-A is scheduled to arrive in lunar orbit beginning on Saturday, December 31, and GRAIL-B on Sunday, January 1. On New Year’s Eve, the pair of probes will fire their engine to slow down so that it could be captured into orbit. This move will be repeated by the other the following day.

Once in orbit, the pair will spend two months following each other around the moon. Scientists back on Earth will measure the varying distance between the pair of spaceships to calculate the lunar gravity field.

Speaking Monday, the team expressed confidence that the mission will continue to perform flawlessly, adding that they expect to gather an unprecedented amount of data from the mission.

“Both spacecraft have performed essentially flawlessly since launch, but one can never take anything for granted in this business,” said mission chief scientist Maria Zuber of the Massachusetts Institute of Technology.

Engineers said the chances of the probes overshooting are slim since their trajectories have been precise. Getting struck by a cosmic ray may prevent the completion of the engine burn and they won’t get boosted into the right orbit.

The straight-line distance from Earth to the moon is about 250,000 miles. It took NASA’s Apollo moon crews about three days to cover that distance. Each of the GRAIL twins is taking about 30 times that long and covering more than 2.5 million miles to get there. This low-energy, high-cruise time trajectory is beneficial for mission planners and controllers, as it allows more time for spacecraft checkout. NASA said the path would allow the program to save money and increase the chances of a successful mission.

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FOUND! Another earth and sun

A ‘habitable’ earth-like planet, which is orbiting around a sun-like star 600 light years away, has been discovered in our galaxy for the first time, researchers say. A team of researchers from NASA’s Kepler Mission has discovered what could be a large, rocky planet with a surface temperature of
about 72 degrees Fahrenheit, comparable to a comfortable spring day on Earth.

The discovery team, led by William Borucki of the NASA Ames Research Center, used photometric data from the NASA Kepler space telescope, which monitors the brightness of 155,000 stars.

Earth-size planets whose orbital planes are aligned such that they periodically pass in front of their stars result in tiny dimmings of their host star’s light dimmings that can only be measured by a highly specialized space telescope like Kepler.

The host star lies about 600 light-years away from us toward the constellations of Lyra and Cygnus.

The star, a G5 star, has a mass and a radius only slightly smaller than that of our Sun, a G2 star. As a result, the host star is about 25 percent less luminous than the Sun.

The planet orbits the G5 star with an orbital period of 290 days, compared to 365 days for the Earth, at a distance about 15 percent closer to its star than the Earth from the Sun. This results in the planet’s balmy temperature. It orbits in the middle of the star’s habitable zone, where liquid water is expected to be able to exist on the surface of the planet.

Liquid water is necessary for life as we know it, and this new planet might well be not only habitable, perhaps even inhabited.

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Killer flares won't destroy Earth, says NASA

NASA's explained - with some weariness, one imagines - that next year really isn't going to see the release of any massive solar flares which could destroy the Earth.

For a start, it points out, the solar maximum doesn't actually coincide with any Mayan end-of-world predictions, but will arrive late in 2013 or early 2014.

And in any case, everybody over the age of 11 has already experienced one solar maximum and lived to tell the tale.

"Most importantly, however, there simply isn't enough energy in the sun to send a killer fireball 93 million miles to destroy Earth," says NASA.

That's the good news - but the bad news is that solar flares could cause some pretty considerable damage. While the heat of a solar flare can't make it all the way to our globe, electromagnetic radiation and energetic particles certainly can.

This can temporarily alter the upper atmosphere creating disruptions with signal transmission from, say, a GPS satellite, which could cause it to be off by many yards.

Even more disruptively, coronal mass ejections (CMEs) can propel bursts of particles and electromagnetic fluctuations right into the Earth's atmosphere. These can induce electric fluctuations at ground level that could blow out transformers in power grids, and can also collide with satellite electronics systems and cause disruptions.

"In an increasingly technological world, where almost everyone relies on cell phones and GPS controls not just your in-car map system, but also airplane navigation and the extremely accurate clocks that govern financial transactions, space weather is a serious matter," says NASA.

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