Space Shuttle Endeavour to Launch No Earlier Than May 16

NASA is now aiming to launch the space shuttle Endeavour on its final flight no earlier than May 16 – pushing the mission back another week to give ground crews more time to complete and test repairs to the orbiter.

Top NASA managers met may6th afternoon to assess progress on repairs to failed heaters that caused the agency to call off its first launch attempt on April 29. The heaters protect a crucial power unit, and without them, the unit would likely freeze on orbit and be unable to serve its role as one of three power sources for Endeavour's hydraulic systems during re-entry and landing.

Technicians worked on repairs all week and will continue to test the electrical circuitry that caused the initial postponement of Endeavour's STS-134 mission. Repair work will continue through the weekend, NASA officials said, and mission managers will hold a news briefing on Monday (May 9) to discuss the status of the work.

NASA Selects Investigations for Future Key Missions

NASA has selected three science investigations from which it will pick one potential 2016 mission to look at Mars' interior for the first time; study an extraterrestrial sea on one of Saturn's moons; or study in unprecedented detail the surface of a comet's nucleus. NASA's Jet Propulsion Laboratory, Pasadena, Calif., would lead the Mars investigation.

Each investigation team will receive $3 million to conduct its mission's concept phase or preliminary design studies and analyses. After another detailed review in 2012 of the concept studies, NASA will select one to continue development efforts leading up to launch. The selected mission will be cost-capped at $425 million, not including launch vehicle funding.

NASA's Discovery Program requested proposals for spaceflight investigations in June 2010. A panel of NASA and other scientists and engineers reviewed 28 submissions. The selected investigations could reveal much about the formation of our solar system and its dynamic processes. Three technology developments for possible future planetary missions also were selected.

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Star Formation Linked to Sonic Booms

ESA's Herschel space observatory has revealed that nearby interstellar clouds contain networks of tangled gaseous filaments. Intriguingly, each filament is approximately the same width, hinting that they may result from interstellar sonic booms throughout our Galaxy. The filaments are huge, stretching for tens of light years through space and Herschel has shown that newly-born stars are often found in the densest parts of them. One filament imaged by Herschel in the Aquila region contains a cluster of about 100 infant stars.

Such filaments in interstellar clouds have been glimpsed before by other infrared satellites, but they have never been seen clearly enough to have their widths measured. Now, Herschel has shown that, regardless of the length or density of a filament, the width is always roughly the same. "This is a very big surprise," says Doris Arzoumanian, Laboratoire AIM Paris-Saclay, CEA/IRFU, the lead author on the paper describing this work. Together with Philippe André from the same institute and other colleagues, she analysed 90 filaments and found they were all about 0.3 light years across, or about 20,000 times the distance of Earth from the Sun. This consistency of the widths demands an explanation.

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NASA's Next Generation Space Telescope Marks Key Milestone

The first six of 18 segments that will form NASA's James Webb Space Telescope's primary mirror for space observations will begin final round-the-clock cryogenic testing this week. These tests will confirm the mirrors will respond as expected to the extreme temperatures of space prior to integration into the telescope's permanent housing structure. The X-ray and Cryogenic Facility at NASA's Marshall Space Flight Center in Huntsville, Ala. will provide the space-like environment to help engineers measure how well the telescope will image infrared sources once in orbit.

Each mirror segment measures approximately 4.3 feet in diameter to form the 21.3 foot, hexagonal telescope mirror assembly critical for infrared observations. Each of the 18 hexagonal-shaped mirror assemblies weighs approximately 88 pounds. The mirrors are made of a light and strong metal called beryllium, and coated with a microscopically thin coat of gold to enabling the mirror to efficiently collect light.

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Houston Deserves a Space Shuttle for Display, Astronaut Spouses Say

The spouses of two astronauts who died in the space shuttle Columbia accident have joined Houston’s vociferous campaign to win a space shuttle for display once NASA retires the orbiter fleet this year. Houston, home of NASA's astronaut corps and shuttle mission control, is hoping to be among the few sites in the country awarded a shuttle for public display when the 30-year program comes to an end. Houston has stepped up its campaign recently as the competition has become increasingly fierce.

For its part, Space Center Houston has some grand plans in the works should it receive a shuttle. "We currently have a building, about 53,000 square feet, that would house the orbiter," Allen said. "The theme we're looking at for the exhibits is the human side of the orbiter, what the astronauts were able to accomplish." Allen's not being picky. He said any of NASA's orbiters Discovery, Endeavour or Atlantis — would be welcome in Houston."We think we could tell that story about any of the three vehicles," he said.The center receives about 750,000 visitors a year, he said, and has hosted almost 14 million people since it opened in 1992.

Waiter, There's Metal in My Moon Water

Bring a filter if you plan on drinking water from the moon. Water ice recently discovered in dust at the bottom of a crater near the moon's south pole is accompanied by metallic elements like mercury, magnesium, calcium, and even a bit of silver. Now you can add sodium to the mix, according to Dr. Rosemary Killen of NASA's Goddard Space Flight Center in Greenbelt, Md.

Recent discoveries of significant deposits of water on the moon were surprising because our moon has had a tough life. Intense asteroid bombardments in its youth, coupled with its weak gravity and the Sun's powerful radiation, have left the moon with almost no atmosphere. This rendered the lunar surface barren and dry, compared to Earth.

However, due to the moon's orientation to the Sun, scientists theorized that deep craters at the lunar poles would be in permanent shadow and thus extremely cold, and able to trap volatile material like water as ice if such material were somehow transported there, perhaps by comet impacts or chemical reactions with hydrogen, a major component of the solar wind.

LRO Could Have Given Apollo 14 Crew Another Majestic View

Although the Apollo 14 mission to the moon was filled with incredible sights and was completely successful it met all its science goals the crew experienced a bit of a disappointment at missing the spectacular view from the rim of a 1,000-foot-wide crater. They might have gazed into its depths if they had the high-resolution maps now available from NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft.

Pressure was on the Apollo 14 mission, launched January 31, 1971, from the start. The Apollo 13 landing had to be aborted because an oxygen tank explosion crippled the spacecraft as it was on its way to the moon. It was a heroic effort just to return the crew safely to Earth, but the Apollo 14 team knew a second failure would probably result in cancellation of the remaining Apollo missions.

Hinode Observes Annular Solar Eclipse

On January 4, the Hinode satellite captured these breathtaking images of an annular solar eclipse. An annular eclipse occurs when the moon, slightly more distant from Earth than on average, moves directly between Earth and the sun, thus appearing slightly smaller to observers' eyes; the effect is a bright ring, or annulus of sunlight, around the silhouette of the moon. Hinode, a Japanese mission in partnership with NASA, NAOJ, STFC, ESA, and NSC, currently in Earth orbit, is studying the Sun to improve our understanding of the mechanisms that power the solar atmosphere and drive solar eruptions.

IBEX Spacecraft Finds Discoveries Close to Home

Imagine floating 35,000 miles above the sunny side of Earth. Our home planet gleams below, a majestic whorl of color and texture. All seems calm around you. With no satellites or space debris to dodge, you can just relax and enjoy the black emptiness of space.

But looks can be deceiving.

In reality, you've unknowingly jumped into an invisible mosh pit of electromagnetic mayhem — the place in space where a supersonic "wind" of charged particles from the Sun crashes head-on into the protective magnetic bubble that surrounds our planet. Traveling at a million miles per hour, the solar wind's protons and electrons sense Earth's magnetosphere too late to flow smoothly around it. Instead, they're shocked, heated, and slowed almost to a stop as they pile up along its outer boundary, the magnetopause, before getting diverted sideways.

Space physicists have had a general sense of these dynamic goings-on for decades. But it wasn't until the advent of the Interstellar Boundary Explorer or IBEX, a NASA spacecraft launched in October 2008, that they've been able to see what the human eye cannot: the first-ever images of this electromagnetic crash scene. They can now witness how some of the solar wind's charged particles are being neutralized by gas escaping from Earth's atmosphere.

A New Way to See Atoms

IBEX wasn't designed to keep tabs on Earth's magnetosphere. Instead, its job is to map interactions occurring far beyond the planets, 8 to 10 billion miles away, where the Sun's own magnetic bubble, the heliosphere, meets interstellar space.

IBEX found that Energetic Neutral Atoms, or ENAs, are coming from a region just outside Earth's magnetopause where nearly stationary protons from the solar wind interact with the tenuous cloud of hydrogen atoms in Earth's exosphere. Credit: NASA/Goddard Space Flight Center

Only two spacecraft, Voyagers 1 and 2, have ventured far enough to probe this region directly. IBEX, which travels in a looping, 8-day-long orbit around Earth, stays much closer to home, but it carries a pair of detectors that can observe the interaction region from afar.

Here's how: When fast-moving protons in the solar wind reach the edge of the heliosphere, they sometimes grab electrons from the slower-moving interstellar atoms around them, like batons getting passed between relay runners. This charge exchange creates electrically neutral hydrogen atoms that are no longer controlled by magnetic fields. Suddenly, they're free to go wherever they want — and because they're still moving fast, they quickly zip away from the interstellar boundary in all directions.

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This animation shows a neutral solar particle's path leaving the Sun, following the magnetic field lines out to the Heliosheath. The solar particle hits a hydrogen atom, stealing it's electron and we follow it until we see it hit one of IBEXs detectors. Credit: NASA/Goddard Space Flight Center

Some of these "energetic neutral atoms," or ENAs, zip past Earth, where they're recorded by IBEX. Its two detectors don't take pictures with conventional optics. Instead, they record the number and energy of atoms arriving from small spots of sky about 7 degrees across (the apparent size of a tennis ball held at arm's length). Because its spin axis always points at the Sun, the spacecraft slowly turns throughout Earth's orbit and its detectors scan overlapping strips that create a complete 360 degrees map every six months.

A Collision Zone Near Earth

Because IBEX is orbiting Earth, it also has a front-row seat for observing the chaotic pileup of solar-wind particles occurring along the "nose" of Earth's magnetopause, about 35,000 miles out. ENAs are created there too, as solar-wind protons wrest electrons from hydrogen atoms in the outermost vestiges of our atmosphere, the exosphere.

Other spacecraft have attempted to measure the density of the dayside exosphere, without much success. NASA's Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft probably detected ENAs from this region a decade ago, but its detectors didn't have the sensitivity to pinpoint or measure the source.

Now, thanks to IBEX, we know just how tenuous the outer exosphere really is. "Where the interaction is strongest, there are only about eight hydrogen atoms per cubic centimeter," explains Stephen A. Fuselier, the Lockheed Martin Space Systems researcher who led the mapping effort. His team's results appear in the July 8 issue of Geophysical Research Letters.

The key observations were made in March and April 2009, when IBEX was located far from Earth — about halfway to the Moon's orbit — and its detectors could scan the region directly in front of the magnetopause. During some of the March observations, the European Space Agency's Cluster 3 spacecraft was positioned just in front of the magnetopause, where it measured the number of deflected solar-wind protons directly. "Cluster played a very important role in this study," Fuselier explains. "It was in the right place at the right time."

Artist concept of the IBEX satellite. Credit: NASA/Goddard Space Flight Center

The new IBEX maps show that the ENAs thin out at locations away from the point of peak intensity. This falloff makes sense, Fuselier says, because Earth's magnetopause isn't spherical. Instead, it has a teardrop shape that's closest to Earth at its nose but farther away everywhere else. So at locations well away from the magnetopause's centerline, even fewer of the exosphere's hydrogen atoms are hanging around to interact with the solar wind. "No exosphere, no ENAs," he explains.

A Versatile Spacecraft

Since its launch, IBEX has also scanned another nearby world, with surprising results. The moon has no atmosphere or magnetosphere, so the solar wind slams unimpeded into its desolate surface. Most of those particles get absorbed by lunar dust. In fact, space visionaries wonder if the moon's rubbly surface has captured enough helium-3, an isotope present in tiny amounts in the Sun's outflow, to serve as a fuel for future explorers.

Yet cosmic chemists have long thought that some solar-wind protons must be bouncing off the lunar surface, becoming ENAs through charge exchange as they do. So does the moon glow in IBEX's scans? Indeed it does, says David J. McComas of Southwest Research Institute in San Antonio, Texas, who serves as the mission's Principal Investigator.

In a report published last year in Geophysical Research Letters, McComas and other researchers conclude that about 10 percent of the solar-wind particles striking the Moon escape to space as ENAs detectable by IBEX. That amounts to roughly 150 tons of recycled hydrogen atoms per year.

Meanwhile, the squat, eight-sided spacecraft continues its primary task of mapping the interactions between the outermost heliosphere and the interstellar medium that lies beyond. McComas and his team are especially eager to learn more about the mysterious and unexpected "ribbon" of ENAs that turned up in the spacecraft's initial all-sky map.

At NASA's Goddard Space Flight Center in Greenbelt, Md., IBEX Mission Scientist Robert MacDowall says the spacecraft should be able to continue its observations through at least 2012. "We weren't sure those heliospheric interactions would vary with time, but they do," he explains, "and it's great that IBEX will be able to record them for years to come."

For more information visit http://www.nasa.gov/mission_pages/ibex/em-crash.html

Cassini Bags Enceladus 'Tigers'

NASA's Cassini spacecraft has successfully completed its flyby over the "tiger stripes" in the south polar region of Saturn's moon Enceladus and has sent back images of its passage. The spacecraft also targeted the moon Tethys.

The tiger stripes are actually giant fissures that spew jets of water vapor and organic particles hundreds of kilometers, or miles, out into space. While the winter is darkening the moon's southern hemisphere, Cassini has its own version of "night vision goggles" -- the composite infrared spectrometer instrument - to track heat even when visible light is low. It will take time for scientists to assemble the data into temperature maps of the fissures.

The camera was pointing toward Enceladus at approximately 348,913 kilometers (216,805 miles) away, and the image was taken using the CL1 and GRN filters. This image has not been validated or calibrated. A validated/calibrated image will be archived with the NASA Planetary Data System in 2011. Image Credit: NASA/JPL/Space Science Institute

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

More raw images from the Enceladus flyby, dubbed "E11," are available at: http://saturn.jpl.nasa.gov/photos/raw/

More information about the Cassini-Huygens mission is at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20100814.html

Backpack, Communications Network Face Desert Test

Science experiments don't always involve bubbling beakers and people dressed in lab coats and goggles. In the case of NASA's Desert RATS project, an experiment can look like a plastic box bolted to a backpack frame and be carried around the Arizona desert for a month.

Inside the plastic box is a host of off-the-shelf electronics capable of telling the backpacker where he is, letting him talk to distant colleagues and beaming pictures of notable objects to geologists and other scientists.

"The backpack tells you where you are, where you were and it allows you to communicate and share your experience with someone in a different location," said Marc Seibert, a senior research engineer at NASA's Kennedy Space Center. "This backpack has been dreamed about for 10 years."

The backpack is an important part of Kennedy's role in the Desert Research and Technology Studies project, which is set up as a large-scale experiment to find out what equipment and operations scenarios NASA needs to explore the surface of an alien world, such as an asteroid, the moon or Mars.

A team of astronauts, scientists and engineers from several NASA centers head to Arizona's desert each year to simulate the unique environment of space explorers. The effort is meant to test equipment and people to find out the best way to explore another world.

Kennedy's engineers develop the communications, navigation and data transmission networks needed, a task that includes a semitrailer set up as a mission operations center, a command vehicle, a specialized RV, a pair of Humvees plus enough communications gear to set up a wireless network for a small crew of explorers to talk back to "Earth" like they will from other planets.

Equipment from other centers, such as a pair of large rovers, has to work on the same communications network. The rovers, for example, relay the signals from the backpacks to the mission operations center.

Although the area they test in is not a perfect stand-in for the moon or Mars in terms of having breathable air and normal gravity, the site does a pretty good job of isolating the participants, said Mike Miller, communications research engineer at Kennedy.

"We have to take everything to the site, just like we will to other planet surfaces," Miller said.

The research program began 13 years ago, and grows in complexity with each annual run. The 2010 program is focused largely on seeing how effectively astronauts can explore a foreign surface under different communications scenarios and rover modes of operation. It also will put pressure on the scientists to have daily plans ready when the explorers awake each day. That means long nights of studying the day's findings to find out what should be done the next.

"This is probably the highest fidelity lunar simulation that's ever been done," Seibert said.

The backpack carries a pair of cameras, a GPS antenna to pinpoint location and all the electronics needed to store then transmit information. The person wearing the backpack controls its systems using an electronic wrist display, supplied by NASA's Glenn Research Center in Ohio, that is generations ahead of the flip cards Apollo astronauts used during the first trips to the moon. Researchers will also test an iPod Touch from NASA's Johnson Space Center in Houston.

Image above: Mike Miller demonstrates one of the backpacks his team designed and built for the Desert Research and Technology Studies project's upcoming field test in Arizona. Miller led the team that developed the backpacks. The backpacks are equipped with GPS antennas, communications components and cameras. They are meant to show researchers what an astronaut might need to explore an alien world and give designers a look at the hardships the equipment could encounter. Photo credit: NASA/Frank Michaux

Right now, the backpack and its host of attached gear only has to stand up to the winds and heat of a desert on Earth.

"Environment is a big thing out there," Miller said. "The winds are very high, it gets very hot. We are pretty much out in the middle of nowhere."

Designers don't have to worry just yet about the life support systems that would be required for any astronaut working on another world. The life support functions will be incorporated into the backpacks as they evolve and improve. Other parts of the backpack design will be incorporated into the rover so the astronauts can quickly leave the vehicle for a spacewalk.

Miller said the month-long exercise should show them whether the design works technically and what can be improved.

Image above: Isaac Hutson assembles components at NASA's Kennedy Space Center in Florida for one of the backpacks that will be tested during the Desert Research and Technology Studies project's upcoming field test in Arizona. The backpacks are equipped with GPS antennas, communications components and cameras. Photo credit: NASA/Frank Michaux

"Success would be to have all the systems up and working, for the scientists to get the science data and the test team to meet their objectives," Miller said.

Miller and his team were given the backpack assignment only a couple months before the equipment had to be assembled and shipped out.

"We only had two to three months here for everything, the design and building, getting the parts, everything," Miller said as others on his team put the finishing touches on a couple of backpacks.

With the short time frame, Miller said his group worked with Glenn partners and with off-the-shelf equipment to get the job done. The software for the controls was written from scratch to make the gear work with each other and operate to their needs.

"The whole communications infrastructure has been upgraded this year," Miller said.

The biggest challenge, he said, was keeping the weight down since the individual components could not be made from scratch by Miller's team.

Between excursions, the Desert RATS participants catalog what they've learned and look at ways to incorporate changes for the next one, along with passing on changes to other in-depth research programs NASA runs.

The backpack's capabilities are designed with space exploration in mind, but the arrangement may have applications for earthbound explorers, too. Basically, a geologist or other explorer could make a solo trek with the backpack and, on his return, play back the whole trip or selected highlights for those who weren't on the journey.

"Any explorer could use this backpack," Seibert said.

For more information visit http://www.nasa.gov/centers/kennedy/moonandmars/desert_rats_backpack.html

This Month in Exploration - August

From the early days of experimental airplanes to NASA’s soaring space shuttles, the evolution of flight has mirrored the evolution of society. The ongoing scientific discoveries that are part of aeronautics and space flight have improved life on Earth and allowed humans to begin investigating the secrets of the universe. “This Month in Exploration” presents the rich history of human flight, contextualizing where we’ve been and examining the exploration history NASA is making today.

100 Years Ago

August 31, 1910: Glenn Curtiss established a record for longest flight over water when he completed a course from Euclid beach in Cleveland, Ohio to Cedar Point in Sandusky, Ohio. Flying his biplane over Lake Erie parallel to the shore, Curtiss completed the trip in about an hour and fifteen minutes.

A Loening Amphibian aircraft similar to the three used on the MacMillan Arctic Expedition. Credit: NASA

85 Years Ago

August 1, 1925: Under the command of Lt. Cmdr. Richard E. Byrd, a U.S. Naval Air detail began aerial exploration of a 30,000-square-mile area near Etah, North Greenland using three Loening amphibian seaplanes introduced the previous year. The excursion was part of the MacMillan Arctic Expedition, the United States’ contribution to the global race to Earth’s last unexplored frontiers, the North and South Poles.

75 Years Ago

August 28, 1935: The Equipment Laboratory at Wright Field tested automatic radio-navigation equipment, called the Sperry automatic pilot, by mechanically linking it to a standard radio compass.

50 Years Ago

August 12, 1960: NASA launched its first communications satellite, the Echo 1, via a Thor- Delta rocket from Vandenberg Air Force Base. The satellite transmitted a radio message from President Dwight D. Eisenhower across the nation, demonstrating the feasibility of global radio communications via satellites. Echo 1 was the most visible and largest satellite launched at that time. Although the mission was successful, it was quickly superseded by active-repeater communications satellites such as Telstar.

A static inflation test of the 135 foot satellite Echo 1. Credit: NASA

45 Years Ago

August 21-29, 1965: NASA launched the Gemini-V via Titan-II rocket. Several records were set during this eight-day orbital flight, including the single longest manned spaceflight, total U.S. manned hours in space and a new altitude record for an American spacecraft. American astronaut Gordon Cooper was also the first man to make a second orbital flight and achieved the record for the most spaceflight time.

35 Years Ago

August 20, 1975: NASA launched Viking 1 from NASA’s Kennedy Space Center, Fla. It was the first of two spacecraft on the historic mission to the planet Mars. The primary objectives of the Viking mission were to return high-resolution images of the Martian surface, analyze the structure and composition of the atmosphere and surface and search for evidence of life on Mars.

25 Years Ago

August 27, 1985: NASA launched space shuttle Discovery (STS-51I) from NASA’s Kennedy Space Center, Fla. The shuttle deployed three communications satellites and retrieved, repaired and re-launched the TELSAT-1 Communications Satellite, Syncom IV-3.

10 Years Ago

August 9, 2000: The European Space Agency launched the second pair of Cluster II mission satellites, named Rumba and Tango, aboard a Soyuz-Fregat rocket from Russia’s Baikonur Cosmodrome. The Cluster mission used simultaneous measurements from four satellites to provide detailed analysis of the effects of solar wind on Earth’s magnetic field. The mission is still in effect today and has resulted in around 1000 scientific publications in peer-reviewed journals.

Astronaut Neil A. Armstrong in the Lunar Module during the Apollo 11 lunar landing mission. Credit: NASA

5 Years Ago

August 12, 2005: NASA launched the Mars Reconnaissance Orbiter (MRO) from NASA’s Kennedy Space Center, Fla. aboard the first Atlas V rocket used for an interplanetary mission. The ongoing mission was to map the physical features of Mars, including its atmosphere and its subterranean layering.

Present Day

August 5, 2010: Neil A. Armstrong turns 80 this year. Born in Wapakoneta, Ohio in 1930, Armstrong was the first person to walk on the moon. He is credited with the famous quote: "That's one small step for a man, one giant leap for mankind."

August 22, 2010: Science fiction writer Ray Bradbury was born 100 years ago on this day in Waukegan, Ill. He wrote “The Martian Chronicles” published in 1949. Among his poems is one inspired by a trip to NASA’s Kennedy Space Center, Fla. where he compared his tour of the Saturn hanger to “walking around inside Shakespeare’s head.”

For more information visit http://www.nasa.gov/exploration/thismonth/this_month_aug10.html

Blowing in the Wind: Cassini Helps with Dune Whodunit

The answer to the mystery of dune patterns on Saturn's moon Titan did turn out to be blowing in the wind. It just wasn't from the direction many scientists expected.

Basic principles describing the rotation of planetary atmospheres and data from the European Space Agency's Huygens probe led to circulation models that showed surface winds streaming generally east-to-west around Titan's equatorial belt. But when NASA's Cassini spacecraft obtained the first images of dunes on Titan in 2005, the dunes' orientation suggested the sands – and therefore the winds – were moving from the opposite direction, or west to east.

A new paper by Tetsuya Tokano in press with the journal Aeolian Research seeks to explain the paradox. It explains that seasonal changes appear to reverse wind patterns on Titan for a short period. These gusts, which occur intermittently for perhaps two years, sweep west to east and are so strong they do a better job of transporting sand than the usual east-to-west surface winds. Those east-to-west winds do not appear to gather enough strength to move significant amounts of sand.

A related perspective article about Tokano's work by Cassini radar scientist Ralph Lorenz, the lead author on a 2009 paper mapping the dunes, appears in this week's issue of the journal Science.

"It was hard to believe that there would be permanent west-to-east winds, as suggested by the dune appearance," said Tokano, of the University of Cologne, Germany. "The dramatic, monsoon-type wind reversal around equinox turns out to be the key."

Cassini radar sees sand dunes on Saturn's giant moon Titan (upper photo) that are sculpted like Namibian sand dunes on Earth (lower photo). The bright features in the upper radar photo are not clouds but topographic features among the dunes. Image credit: NASA/JPL - upper photo; NASA/JSC - lower photo

The dunes track across the vast sand seas of Titan only in latitudes within 30 degrees of the equator. They are about a kilometer (half a mile) wide and tens to hundreds of kilometers (miles) long. They can rise more than 100 meters (300 feet) high. The sands that make up the dunes appear to be made of organic, hydrocarbon particles. The dunes' ridges generally run west-to-east, as wind here generally sheds sand along lines parallel to the equator.

Scientists predicted winds in the low latitudes around Titan's equator would blow east-to-west because at higher latitudes the average wind blows west-to-east. The wind forces should balance out, based on basic principles of rotating atmospheres.

Tokano re-analyzed a computer-based global circulation model for Titan he put together in 2008. That model, like others for Titan, was adapted from ones developed for Earth and Mars. Tokano added in new data on Titan topography and shape based on Cassini radar and gravity data. In his new analysis, Tokano also looked more closely at variations in the wind at different points in time rather than the averages. Equinox periods jumped out.

Equinoxes occur twice a Titan year, which is about 29 Earth years. During equinox, the sun shines directly over the equator, and heat from the sun creates upwelling in the atmosphere. The turbulent mixing causes the winds to reverse and accelerate. On Earth, this rare kind of wind reversal happens over the Indian Ocean in transitional seasons between monsoons.

The episodic reverse winds on Titan appear to blow around 1 to 1.8 meters per second (2 to 4 mph). The threshold for sand movement appears to be about 1 meter per second (2 mph), a speed that the typical east-to-west winds never appear to surpass. Dune patterns sculpted by strong, short episodes of wind can be found on Earth in the northern Namib sand seas in Namibia, Africa.

Scientists have used data from the Cassini radar mapper to map the global wind pattern on Saturn's moon Titan using data collected over a four-year period, as depicted in this image. Image credit: NASA/JPL/Space Science Institute

"This is a subtle discovery -- only by delving into the statistics of the winds in the model could this rather distressing paradox be resolved," said Ralph Lorenz, a Cassini radar scientist based at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. "This work is also reassuring for preparations for proposed future missions to Titan, in that we can become more confident in predicting the winds which can affect the delivery accuracy of landers, or the drift of balloons."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the Cassini-Huygens mission for NASA's Science Mission Directorate. The Cassini orbiter was designed, developed and assembled at JPL. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries. JPL is a division of the California Institute of Technology in Pasadena.

More Cassini information is available, at http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20100729.html

NASA's ATHLETE Warms Up for High Desert Run

Engineers from NASA's Jet Propulsion Laboratory are currently putting their All-Terrain, Hex-Limbed, Extra-Terrestrial Explorer (ATHLETE) through a series of long-drive tests on the long, dirt roads found adjacent to JPL. The JPL grounds do not include an unpaved area of sufficient size for testing such a large robot over a long distance. Some of the dirt roads in the Arroyo Seco (a wash located next to JPL) are wide enough for ATHLETE, and its close proximity to JPL allows the robot to be secured in its hangar between test runs.

The engineers want to test the moon rover's ability to meet a NASA milestone of traveling at least 40 kilometers (25 miles) over 14 days under its own power. The official demonstration is slated to begin in the Arizona high desert next month.

Engineers test the ATHLETE moon rover on one of the long dirt roads found just outside JPL. Image credit: NASA

ATHLETE is a 1/2-scale working prototype of a robot under development to transport habitats and other cargo on the surface of the Moon or Mars. The ATHLETE concept is a level cargo deck carried by six wheels, each on the end of a configurable leg. The prototype stands approximately 4.5 meters (15 feet) tall and 4.5 meters (15 ft) wide and weighs about (about 2,300 kilograms (2.5 tons). The robot moves relatively slowly, with a top speed during traverse of approximately 2 kilometers per hour (1.25 mph).

For more information about ATHLETE, including photos and video clips, visit: http://athlete.jpl.nasa.gov/.

It takes a lot of hard work, ingenuity and creativity to build a rover like ATHLETE. And it takes a lot of creativity of a different sort to make ATHLETE "dance." See the results of that effort in a fast-action video of ATHLETE bustin' a move.

For more information visit http://www.nasa.gov/topics/moonmars/features/athlete20100730.html

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GRAIL Spacecraft Takes Shape

Engineers have conducted a fuel tank check of one of NASA's GRAIL mission spacecraft (Gravity Recovery and Interior Laboratory), scheduled for launch in 2011. Confirming the size and fit of manufactured components is one of the steps required prior to welding the spacecraft's fuel tanks into the propulsion system's feed lines.

The image was taken on June 29, 2010, during the propulsion subsystem assembly and integration effort in the Space Support Building clean room at Lockheed Martin Space Systems in Denver.

Engineers conduct checks on one of NASA's GRAIL spacecraft in the Space Support Building at Lockheed Martin Space Systems in Denver. Image credit: NASA/JPL/LockheedMartin

The GRAIL mission will fly twin spacecraft (spacecraft "A" and "B") in tandem orbits around the moon for several months to measure its gravity field in unprecedented detail. The mission will also answer longstanding questions about Earth's moon, and provide scientists a better understanding of how Earth and other rocky planets in the solar system formed.

For more information about GRAIL, please visit: http://moon.mit.edu/ .

For more information visit http://www.nasa.gov/topics/moonmars/features/grail20100728.html

WISE Peers Into the Stellar Darkness

New stars are forming inside this giant cloud of dust and gas as seen in infrared light by NASA's Wide-field Infrared Survey Explorer, or WISE. Sprawling across the constellation Vela is a complex of dark, dense clouds of dust and gas, difficult to detect with telescopes that see only visible light. The complex is called the Vela Molecular Cloud Ridge. This ridge may form part of the edge of the Orion spiral arm spur in our Milky Way galaxy. Astronomers mapping out the region in radio light in the late 1980s found four distinct regions of the densest gas and named them clouds A, B, C and D. This image takes in the first of those clouds, Vela A.

Vela A is about 3,300 light-years away. This image of Vela A covers a region on the sky over 4.5 full moons wide and over 3 full moons tall, spanning about 130 light-years in space. The core of the cloud is being excavated by the radiation and winds from hot, young stars. The energy from the new stars is absorbed by the surrounding dust. This hides them from view in visible light, but the heated dust glows in infrared light (seen here in green and red). Sprinkled around Vela A are a few groups of sources that appear very red in this image, and have no known counterparts in visible-light images of the region. It's possible that these may be Young Stellar Objects, which are stars in their very infancy enveloped in dust. The infrared light seen from these baby stars does not come directly from the stars, but rather from the dust around them, which glows as the nascent stars heat it.

All four infrared detectors aboard WISE were used to make this mosaic. Color is representational: blue and cyan represent infrared light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust.

Image Credit: NASA/JPL-Caltech/UCLA

For more information visit http://www.nasa.gov/mission_pages/WISE/multimedia/gallery/pia13122.html

Saturn System Moves Oxygen From Enceladus to Titan

Complex interactions between Saturn and its satellites have led scientists using NASA's Cassini spacecraft to a comprehensive model that could explain how oxygen may end up on the surface of Saturn's icy moon Titan. The presence of these oxygen atoms could potentially provide the basis for pre-biological chemistry.

The interactions are captured in two papers, one led by John Cooper and another led by Edward Sittler, published in the journal Planetary and Space Science in late 2009. Cooper and Sittler are Cassini plasma spectrometer team scientists at NASA's Goddard Space Flight Center in Greenbelt, Md.

"Titan and Enceladus, another icy moon of Saturn, are chemically connected by the flow of material through the Saturn system," Cooper said.

In one paper, Cooper and colleagues provide an explanation for forces that could generate the Enceladus geysers that spew water vapor into space. In the other, published in the same issue, Sittler and colleagues describe a unique new process in which oxygen that circulates in the upper atmosphere of Titan can be carried all the way to the surface without further chemical contamination by being encased in carbon cages called fullerenes.

The work draws upon previous work by Sittler and others that model the dynamics of how particles, including water molecules, travel from Enceladus to Titan. At Enceladus the flow process begins with what they call the "Old Faithful" model, after the Old Faithful geyser in Yellowstone National Park. In this model, gas pressure slowly builds up inside Enceladus, then gets released occasionally in geyser-like eruptions.

Unlike terrestrial geysers, or even geyser-like forces on Jupiter's moon Io, the model proposed by Cooper shows that charged particle radiation raining down from Saturn’s magnetosphere can create the forces from below the surface that are required to eject gaseous jets.

Energetic particles raining down from Saturn's magnetosphere – at Enceladus, mostly electrons from Saturn's radiation belts -- can break up molecules within the surface. This process is called radiolysis. Like a process called photolysis, in which sunlight can break apart molecules in the atmosphere, energetic radiation from charged particles that hit an icy surface, like that of Enceladus, can cause damage to molecules within the ice. These damaged molecules can get buried deeper and deeper under the surface by the perpetual churning forces that can repave the icy surface. Meteorites constantly crashing into the surface and splashing out material might also be burying the molecules.

This annotated image collage features Saturn and the moons Titan, Enceladus, Dione, Rhea and Helene, which are being studied by the Cassini mission. Image credit: NASA/JPL/Space Science Institute

When chemically altered icy grains come into contact beneath the surface with icy contaminants such as ammonia, methane and other hydrocarbons, they can produce volatile gases that can explode outward. Such gases can create plumes of the size seen by Cassini. Cooper and colleagues call such icy volatile mechanics "cryovolcanism."

What's unique about the "Old Faithful" model is that it "is a model for cryovolcanism that is based on not only liquid water, but also requires the production of gases by the radiolytic chemistry observed at Enceladus," said Sittler.

The plumes that emanate from Enceladus' south polar region consist of water, ammonia and other compounds. Scientists have known since the 1980s that Saturn's magnetosphere is inexplicably filled with neutral particles. In the intervening decades, particularly since the discovery of plumes jetting out from the south pole of Enceladus, work has shown how some of the water molecules that escape from Enceladus get split up into neutral and charged particles and are transported throughout Saturn's magnetosphere.

Sittler's new model indicates that as these broken water molecules enter Titan's atmosphere, they may be captured by fullerenes—hollow, soccer-ball shaped shells made of carbon atoms. Although the heavy molecules Cassini has detected in the upper atmosphere of Titan may be other molecules, Sittler suggests they are likely fullerenes.

In Sittler's model, the fullerenes then condense into larger clusters that can attach to polycyclic aromatic hydrocarbons—chemical compounds also found on Earth in oil, coal and tar deposits, and as the byproducts of burning fossil fuels. The fullerene clusters form even larger aerosols that travel down to Titan's surface.

This process protects the trapped oxygen from Titan's atmosphere, which is saturated with hydrogen atoms and compounds that are capable of breaking down other molecules. Otherwise, the oxygen would combine with methane in Titan's atmosphere and form carbon monoxide or carbon dioxide. Until now, scientists have not been able to explain how oxygen fits into the picture of the dynamics and chemistry of Saturn and its moons.

As the oxygen-rich aerosols fall to Titan's surface, they are further bombarded by products of galactic cosmic ray interactions with Titan's atmosphere. Cosmic rays bombarding the oxygen-stuffed fullerenes could produce more complex organic materials, such as amino acids, in the carbon-rich and oxygen-loaded fullerenes. Amino acids are considered important for pre-biological chemistry.

Scientists have been able to couple the new models that describe the generation of plumes at Enceladus and oxygen ion capture in fullerenes near the top of Titan's atmosphere to existing theories of the transport of oxygen across the magnetosphere. Taken together, Sittler and Cooper suggest a chemical pathway that allows the oxygen to be introduced to Titan's surface chemistry.

"Cooper and Sittler's work helps us understand more about the potential for chemical interactions among Saturn's moons," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

"The Saturn system is indeed a dynamic place, with the Enceladus plumes creating the E ring and loading the magnetosphere with water which interacts with Titan and the other moons," Spilker said.

The Cassini mission is a joint effort of NASA, the European Space Agency, and the Italian space agency Agenzia Spaziale Italiana. The mission is managed for NASA by the Jet Propulsion Laboratory, a division of the California Institute of Technology. Partners include the U.S. Air Force, Department of Energy, and academic and industrial participants from 19 countries.

For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/saturn20100701.html

The Earth From The Moon

All cameras are susceptible to scattered light. You may have seen scattered light in pictures you have taken looking towards the Sun. Sunlight reflects off the optics and sometimes off the structure of the lens, and often appears as a gradient of brightness across the image. Attaching a baffle to your camera, like we did with the LROC Wide and Narrow Angle Cameras, can minimize this effect. More subtle effects are often present but usually you simply just don't notice artifacts because of strong color contrasts in the scene.

Since the Moon has only very small color contrasts, the LROC team must characterize even subtle scattered light effects within the 7-color Wide Angle Camera (WAC) images. Changes in composition (rock types) result in subtle differences of color, typically about 10% or less. For scientists to make accurate interpretations of WAC color maps, the amount of scattered light must be quantified (and preferably corrected). One way of measuring scattered light is imaging a bright object against a dark background. From the Moon, the Earth serves that function well.

While a series of WAC calibration images of the Earth were being acquired, the Narrow Angle Camera (NAC) was shuttered to capture this spectacular Earth view. The bottom of the Earth was clipped because the prediction of the exact time when the cameras' fields of view would cross the Earth was off by a few seconds.

The Earth as seen from the Moon! LROC NAC mosaic of images snapped on 12 June 2010 during a calibration sequence (Images E130954785L and E130954785R). Credit: NASA/Goddard/Arizona State University

Since the NAC acquires only one line of a picture at a time, the spacecraft had to be nodded across the Earth to build up the scene. The NAC Earth view is actually a mosaic of NAC-Left and NAC-Right images put together after calibration. The distance between the Moon and the Earth was 372,335 km when the picture was taken, with a pixel scale of about 3.7 km, and the center of this view of Earth is 25°N latitude, 114°E longitude (a few hundred kilometers north of Hong Kong).

It was a beautiful clear summer day over the North Pole. You can see ice covering most of the Arctic Ocean with a few leads of open water (dark) starting to open up. If you look very close you can follow the Lena River upstream from the Arctic Ocean all the way to Lake Baikal. Much of the Middle East was clear and you can trace spectacular swirl patterns of folded rock layers through Iran, Afghanistan, and Pakistan. These mountains formed as the Eurasian and Arabian tectonic plates collided.

AP: Arabian Peninsula; CS: Caspian Sea; H: Himalayan Mountains; L: Lena River; I: Indian Ocean; A: Australia; J: Japan; P: Pacific Ocean; large yellow arrow indicates approximate position of the North Pole. Credit: NASA/Goddard/Arizona State University

Browse the full-sized image at the LRO Camera website maintained by Arizona State University.

For more information visit http://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc-20100624-earth.html

'L2' Will be the James Webb Space Telescope's Home in Space

When you ask an astronomer about the James Webb Space Telescope's orbit, they'll tell you something that sounds like it came from a science-fiction novel. The Webb won't be orbiting the Earth –instead we will send it almost a million miles out into space to a place called "L2."

L2 is short-hand for the second Lagrange Point, a wonderful accident of gravity and orbital mechanics, and the perfect place to park the Webb telescope in space. There are five so-called "Lagrange Points" - areas where gravity from the sun and Earth balance the orbital motion of a satellite. Putting a spacecraft at any of these points allows it to stay in a fixed position relative to the Earth and sun with a minimal amount of energy needed for course correction.

The five Lagrangian points for the Sun-Earth system are shown in the diagram below. An object placed at any one of these 5 points will stay in place relative to the other two. Credit: NASA

The term L2 may sound futuristic and mysterious, but the name actually honors a Mathematician born in 1736. The Lagrange points were named after the Italian-born mathematician and astronomer Joseph-Louis Lagrange, who made important contributions to classical and celestial mechanics. Lagrange studied the "three-body problem" (so-called because three bodies are orbiting each other) for the Earth, sun, and moon in 1764, and by 1772 he had found the solution; there are five stable points at which you could put an object and have it stay fixed in place relative to the other two.

In the case of L2, this happens about 930,000 miles away from the Earth in the exact opposite direction from the sun. The Earth, as we know, orbits the sun once every year. Normally, an object almost a million miles farther out from the sun should move more slowly, taking more than a year to complete its orbit around the sun. However, at L2, exactly lined up with both the sun and Earth, the added gravity of the two large bodies pulling in the same direction gives a spacecraft an extra boost of energy, locking it into perfect unison with the Earth's yearly orbit. The Webb telescope will be placed slightly off the true balance point, in a gentle orbit around L2.

Why send the Webb telescope all the way out to L2? When astronomers began to think about where the Webb telescope should be placed in space, there were several considerations to keep in mind. To begin with, the Webb telescope will view the universe entirely in infrared light, what we commonly think of as heat radiation. To give the telescope the best chance of detecting distant, dim objects in space, the coldest temperatures possible are needed.

The James Webb Space Telescope (identified as "JWST" here) relative to the Hubble telescope's orbit around the Earth. Credit: NASA

"A huge advantage of deep space (like L2) when compared to Earth orbit is that we can radiate the heat away," said Jonathan P. Gardner, the Deputy Senior Project Scientist on the Webb Telescope mission and Chief of the Observational Cosmology Laboratory at NASA's Goddard Space Flight Center in Greenbelt, Md. "Webb works in the infrared, which is heat radiation. To see the infrared light from distant stars and galaxies, the telescope has to be cold. Webb's large sunshield will protect it from both Sunlight and Earthlight, allowing it to cool to 225 degrees below zero Celsius (minus 370 Fahrenheit)." For the sunshield to be effective, Webb will need to be an orbit where the sun and Earth are in about the same direction.

With the sun and the Earth in the same part of the sky, the Webb telescope will enjoy an open, unimpeded view of the universe. In comparison, the Hubble Space Telescope is in low-Earth orbit where it goes in and out of the Earth's shadow every 90 minutes. Hubble's view is blocked by the Earth for part of each orbit, limiting where the telescope can look at any given time.

The Spitzer Space Telescope, another infrared telescope, is in orbit around the sun and drifting away from the Earth. Spitzer is already more than 100 million kilometers (60 million miles) away from the Earth, and eventually its path will take it to the other side of the sun. Once we can no longer communicate with Spitzer that means it is at the end of its mission life.

This animation shows the Webb Telescope spacecraft orbiting far from the Earth. Credit: NASA/Chris Meaney (HTSI)

In contrast, a major perk of parking at L2 is the ease of communications. Essentially, the Webb telescope will always be at the same point in space. "We can have continuous communications with Webb through the Deep Space Network (DSN)," Gardner said. "During routine operations, we will uplink command sequences and downlink data up to twice per day, through the DSN. The observatory can perform a sequence of commands (pointing and observations) autonomously. Typically, we will upload a full week's worth of commands at a time, and make updates daily as needed."

Even before the Webb telescope, L2 has been known to astronomers as a good spot for space-based observatories. There are already several satellites in the L2 orbit, including the Wilkinson Microwave Anisotropy Probe, and the Herschel and Planck space observatories. But there's plenty of room for another neighbor, and the Webb telescope will be heading out to L2 in the near future.

The Webb telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.

For more information visit http://www.nasa.gov/topics/universe/features/webb-l2.html

Cassini Getting the Lowdown on Titan This Weekend

NASA's Cassini spacecraft will take its lowest dip through the hazy atmosphere of Saturn's moon Titan in the early morning of June 21 UTC, which is the evening of June 20 Pacific time. This weekend's flyby, which is the 71st Titan flyby of the mission even though it is known as "T70," takes Cassini 70 kilometers (43 miles) lower than it has ever been at Titan before.

Titan's atmosphere applies torque to objects flying through it, much the same way the flow of air would wiggle your hand around if you stuck it outside a moving car window. Cassini mission planners and the NASA Engineering and Safety Center in Hampton, Va., have analyzed the torque applied by the atmosphere in detail to make sure the spacecraft can fly safely at an altitude of 880 kilometers (547 miles) above the surface.

Artist's concept of Cassini's flyby of Saturn's moon Titan. The spacecraft flies to within 880 kilometers (547 miles) of Titan's surface during its 71st flyby of Titan, known as "T70," the lowest in the entire mission. Image credit: NASA/JPL-Caltech

When engineers calculated the most stable angle for the spacecraft to fly, they found it was almost the same as the angle that would enable Cassini to point its high-gain antenna to Earth. So they cocked the spacecraft a fraction of a degree, enabling them to track the spacecraft in real-time during its closest approach. Thrusters will fire throughout the flyby to maintain pointing automatically.

But why does Cassini need to get so low? Read on for the perspective of one Cassini team scientist, César Bertucci: http://blogs.nasa.gov/cm/blog/cassini/posts/post_1276817553169.html

For more information visit http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20100617.html