Posted on by Fraser Cain

Cassini Finds a New Ring Around Saturn

Scientists examining Saturn’s contorted F ring, which has baffled them since its discovery, have found one small body, possibly two, orbiting in the F ring region, and a ring of material associated with Saturn’s moon Atlas.

A small object was discovered moving near the outside edge of the F ring, interior to the orbit of Saturn’s moon Pandora. The object was seen by Dr. Carl Murray, imaging team member at Queen Mary, University of London, in images taken on June 21, 2004, just days before Cassini arrived at Saturn. “I noticed this barely detectable object skirting the outer part of the F ring. It was an incredible privilege to be the first person to spot it,” he said. Murray’s group at Queen Mary then calculated an orbit for the object.

Scientists cannot yet definitively say if the object is a moon or a temporary clump. If it is a moon, its diameter is estimated at four to five kilometers (two to three miles) and it is located 1,000 kilometers (620 miles) from the F ring, Saturn’s outmost ring. It is at a distance of approximately 141,000 kilometers (86,000 miles) from the center of Saturn and within 300 kilometers (190 miles) of the orbit of the moon Pandora. The object has been provisionally named S/2004 S3.

Scientists are not sure if the object is alone. This is because of results from a search through other images that might capture the object to pin down its orbit. The search by Dr. Joseph Spitale, a planetary scientist working with team leader Dr. Carolyn Porco at the Space Science Institute in Boulder, Colo., revealed something strange. Spitale said, “When I went to look for additional images of this object to refine its orbit, I found that about five hours after first being sighted, it seemed to be orbiting interior to the F ring,” said Spitale. “If this is the same object then it has an orbit that crosses the F ring, which makes it a strange object.” Because of the puzzling dynamical implications of having a body that crosses the ring, the inner object sighted by Spitale is presently considered a separate object with the temporary designation S/2004 S 4. S4 is roughly the same size as S3.

In the process of examining the F ring region, Murray also detected a previously unknown ring, S/2004 1R, associated with Saturn’s moon, Atlas. “We knew from Voyager that the region between the main rings and the F ring is dusty, but the role of the moons in this region was a mystery,” said Murray. “It was while studying the F ring in these images that I discovered the faint ring of material. My immediate hunch was that it might be associated with the orbit of one of Saturn’s moons, and after some calculation I identified Atlas as the prime suspect.”

The ring is located 138,000 kilometers (86,000 miles) from the center of Saturn in the orbit of the moon Atlas, between the A ring and the F ring. The width of the ring is estimated at 300 kilometers (190 miles). The ring was first spotted in images taken after orbit insertion on July 1, 2004. There is no way of knowing yet if it extends all the way around the planet.

“We have planned many images to search the region between the A and F rings for diffuse material and new moons, which we have long expected to be there on the basis of the peculiar behavior of the F ring,” said Porco. “Now we have found something but, as is usual for the F ring, what we see is perplexing.”

Searches will continue for further detections of the newfound body or bodies seen in association with the F ring. If the two objects indeed turn out to be a single moon, it will bring the Saturn moon count to 34. The newfound ring adds to the growing number of narrow ringlets around Saturn.

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, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo. UK scientists are playing significant roles in the mission with involvement in six of the 12 instruments onboard the Cassini orbiter and two of the six instruments on the Huygens probe.

Cassini-Huygens 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 and Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The Composite Infrared Spectrometer team is based at NASA’s Goddard Space Flight Center, Greenbelt, Md. For this image and for the latest news about the Cassini-Huygens mission, visit http://www.nasa.gov/cassini. For in-depth mission information, visit http://saturn.jpl.nasa.gov. For more information on the Composite Infrared Spectrometer, visit http://cirs.gsfc.nasa.gov.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

How About a Gigapixel Digital Camera?

ESA?s ?discovery machine? Gaia is designed to photograph one thousand million stars and hundreds of thousands of other celestial objects, so its camera will have to be something truly special.

Indeed, when Gaia lifts off from ESA?s Spaceport at Kourou in French Guiana, sometime after 2010, it will be carrying the largest digital camera in the Solar System. Essentially, Gaia will survey anything in the Universe that it can lay its electronic eyes on. As it spins gently in its orbit, 1.5 million kilometres away from Earth, it will scan the entire sky for stars, planets, asteroids, distant galaxies and everything in between.

The aim is to detect every celestial object down to about a million times fainter than the unaided human eye can see. To do that, it needs a large camera. In fact, there will be 170 separate cameras in Gaia, tiled together in a mosaic to register every object that passes through the field of view.

Scientists call each individual camera a ?charge-coupled device? (CCD). An additional instrument will take the total number of CCDs to over 200.

Each CCD is itself a major piece of hi-tech kit that converts light into electrical charge and stores it in tiny traps known as ?pixels? until the computer reads out this information. With about nine million pixels, Gaia?s CCDs are each between 5 and 10 times larger than those used in digital cameras currently on sale in our shops.

The size of each CCD presents some unique manufacturing challenges. Even in the purest silicon, defects can occur. Typically, with the CCDs that are used in our digital cameras on Earth, perhaps 20 or more are manufactured from the same silicon wafer and one or two rejects are tolerable.

However, the Gaia CCDs are so large that only two will fit onto each silicon wafer. So the chance of a defect occurring in a Gaia CCD is considerable.

To help refine the manufacturing process, ESA is running a prototype production line with the company e2v, who specialise in cutting-edge research quality CCDs. They are the same company that provided most of the scientific CCDs for ESA’s orbiting X-ray observatory XMM-Newton.

?For XMM-Newton, e2v provided 23 flight quality CCDs. This was a major achievement, but for Gaia, we aim to fly more than 200 in all,? says Alexander Short, one of Gaia?s CCD experts at the European Space Technology and Research Centre (ESTEC), in the Netherlands.

Once Gaia is in space, solar activity such as solar flares and ?coronal mass ejections? could damage the CCDs and blur the images.

To minimise the effects of this ?radiation damage? during the mission, Short and colleagues are working on shielding and a number of other solutions to ensure that Gaia can become the most successful discovery machine in the history of astronomy.

Original Source: ESA News Release

Posted on by Fraser Cain

Genesis Capsule Crashes

Helicopters were waiting in Utah to gently catch a capsule from the Genesis probe carrying precious samples of the Sun’s solar wind, but the safe recovery didn’t happen. It appears that the capsule’s parachute failed to open as it entered the Earth atmosphere, and it crashed into the ground at 161 km/h (100 mph). It could take some time to recover the capsule because the charges designed to open the parachute might still be live, and could still explode. The $264 million mission was launched in 2001, and carried delicate wafers of pure silicon, gold, sapphire, and diamond designed to gently catch solar wind particles. It’s unknown how much of the experiment can be recovered at this point.

Posted on by Fraser Cain

Cleaning Up Kennedy Space Center After Frances

For one of the world’s biggest buildings, before and after images captured the force of the storm. With its footprint the size of Texas, hurricane Frances had pounded Cape Canaveral over the weekend and left a natural scar on one of the world’s manmade wonders.

Originally built for assembly of Apollo/Saturn vehicles and later modified to support Space Shuttle operations, the Vehicle Assembly Building (VAB) is often referred to as the only enclosed space big enough for interior clouds to form. But when a hurricane looms off the Florida coast and dark clouds gather to drench the beaches, the novelty of forming interior clouds loses some of its charm.

It is not the tallest, just one of the more spacious. Its high-bay area is 525 feet tall (more than 45 stories high), while its low-bay area is 210 feet tall. The VAB occupies 8 acres of land, making it the largest in volume (129 million cubic feet). The volume is like half the height of the tallest skyscraper, but then with that same tower turned on three axes, with nearly equal height, width and depth. When open, the T-shaped door alone is more than 40 stories tall.

When constructed in the 1960’s to stack the Saturn rockets–each about the size of an aircraft carrier if stood up vertically–the VAB came to symbolize big-scale thinking. In addition to sheltering the Apollo rockets, it could accomodate rollbacks of a shuttle during the predictable fall hurricane season. In total, six skyscrapers could fit inside what is the landmark against an otherwise flat Florida marsh lacking an urban skyline. But from its outset, if NASA needed a building to shelter a moon rocket, then a group of construction engineers would conceive hoisting the biggest one of its kind.

Max Urbahn, who headed the design team of architects and engineers for the Vehicle Assembly Building stated the design challenge well when he said: “The VAB is not so much a building to house a moon vehicle as a machine to build a moon craft. The Launch Control Center that monitors and tests every component that goes into an Apollo vehicle is not so much a building as an almost-living brain.”

When General Thomas Stafford testified to the Presidential blue-ribbon commission on “Moon to Mars and Beyond”, he cited specifically how remarkable the early sixties were for construction on the Florida coast. “In the early 1960’s the Cape was strictly palmettos, rattlesnakes, and palm trees. In 6 years, that was built to the Vehicle Assembly Building (VAB), and we launched the first Saturn flag. And most of it was done with a slide rule.”

As the VAB tried to weather 100 mile-per-hour gales, the adage that ‘build it and they will come’ took on special significance: those who had to evacuate included nearly the entire 14,000 person Kennedy Space Center (KSC). According to its design specifications, the VAB doors can withstand winds of 125 miles per hour and can be opened and closed in a 63 mile-per-hour wind. The building lived up to its design, but its integrity was questionable earlier in the week when Frances looked like it might make landfall with 140 mph force winds.

As NASA Administrator, Sean O’Keefe described in a statement: “Kennedy Space Center suffered significant damage as Hurricane Frances swept across Florida.” After the weekend, early assessment of this landmark facility showed about 820 panels were torn off the VAB during the storm. Initial review of the interior, however, indicated no serious damage to equipment, including two Space Shuttle External Tanks.

Preliminary inspections of the center’s two launch pads indicate they appear in good shape. The SWIFT spacecraft for studying Gamma Ray Bursts, which is scheduled for launch early next month, also appears fine, but the building where it rode out the storm did sustain damage. Also, power was restored today to the third and final Orbital Processing Facility, which houses the Space Shuttle Discovery.

In addition to housing the shuttle rocket stacks, many astrobiology missions have historical ties to critical assets at the Cape. From the Hubble telescope launch to various human missions on space station, the shuttle stack has been mounted in the VAB. In fact the skyline at Cape Canaveral gives a running account of important astrobiology objectives. During a controlled explosion in October 2000, the historical launch pad 41 dating back to 1965 gave way to a new Atlas V tower. That part of the now modified Florida skyline had witnessed the launch of two Viking missions to Mars and Voyager’s planetary probe, both of which had led the way for modern astrobiology missions to the inner and outer solar system.

O’Keefe spoke to the NASA tradition of recovery, when he concluded that “We have a documented history of overcoming adversity and pulling together.” NASA has not assessed yet whether the storm damage will affect the planned spring reflight of the shuttle as it returns to orbit since the Columbia tragedy.

Original Source: NASA Astrobiology Article

Posted on by Fraser Cain

Dark Matter is Tugging at a Galactic Cluster

A nearby galaxy cluster is facing an intergalactic headwind as it is pulled by an underlying superstructure of dark matter, according to new evidence from NASA’s Chandra X-ray Observatory. Astronomers think that most of the matter in the universe is concentrated in long large filaments of dark matter and that galaxy clusters are formed where these filaments intersect.

A Chandra survey of the Fornax galaxy cluster revealed a vast, swept-back cloud of hot gas near the center of the cluster. This geometry indicates that the hot gas cloud, which is several hundred thousand light years in length, is moving rapidly through a larger, less dense cloud of gas. The motion of the core gas cloud, together with optical observations of a group of galaxies racing inward on a collision course with it, suggests that an unseen, large structure is collapsing and drawing everything toward a common center of gravity.

“At a relatively nearby distance of about 60 million light years, the Fornax cluster represents a crucial laboratory for studying the interplay of galaxies, hot gas and dark matter as the cluster evolves.” said Caleb Scharf of Columbia University in New York, NY, lead author of a paper describing the Chandra survey that was presented at an American Astronomical Society meeting in New Orleans, LA. “What we are seeing could be associated directly with the intergalactic gas surrounding a very large scale structure that stretches over millions of light years.”

The infalling galaxy group, whose motion was detected by Michael Drinkwater of the University of Melbourne in Australia, and colleagues, is about 3 million light years from the cluster core, so a collision with the core will not occur for a few billion years. Insight as to how this collision will look is provided by the elliptical galaxy NGC 1404 that is plunging into the core of the cluster for the first time. As discussed by Scharf and another group led by Marie Machacek of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., the hot gas cloud surrounding this galaxy has a sharp leading edge and a trailing tail of gas being stripped from the galaxy.

“One thing that makes what we see in Fornax rather compelling is that it looks a lot like some of the latest computer simulations,” added Scharf. “The Fornax picture, with infalling galaxies, and the swept back geometry of the cluster gas – seen only with the Chandra resolution and the proximity of Fornax – is one of the best matches to date with these high-resolution simulations.”

Over the course of hundreds of millions of years, NGC 1404’s orbit will take it through the cluster core several times, most of the gas it contains will be stripped away, and the formation of new stars will cease. In contrast, galaxies that remain outside the core will retain their gas, and new stars can continue to form. Indeed, Scharf and colleagues found that galaxies located in regions outside the core were more likely to show X-ray activity which could be associated with active star formation.

The wide-field and deep X-ray view around Fornax was obtained through ten Chandra pointings, each lasting about 14 hours. Other members of the research team were David Zurek of the American Museum of Natural History, New York, NY, and Martin Bureau, a Hubble Fellow currently at Columbia.

NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA’s Office of Space Science, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Additional information and images are available at:

http://chandra.harvard.edu
and
http://chandra.nasa.gov

Original Source: Chandra News Release

Posted on by Fraser Cain

Colliding Galaxies Awash With Star Formation

NASA’s Spitzer Space Telescope has set its infrared sight on a major galactic collision and witnessed not death, but a teeming nest of life.

The colliding galaxies, called the Antennae galaxies, are in the process of merging together. As they churn into each other, they throw off massive streamers of stars and dark clouds of dust. Spitzer’s heat-seeking eyes peered through that dust and found a hidden population of newborn stars.

The new Spitzer image, available at http://www.spitzer.caltech.edu/Media/releases/ssc2004-14/visuals.shtml, is reported in one of 86 Spitzer papers published in the September issue of The Astrophysical Journal Supplement. This special all-Spitzer issue comes just after the one-year anniversary of the observatory’s launch, and testifies to its tremendously successful first year in space.

“This abundance of Spitzer papers just one year after launch shows that the telescope is truly providing a new window on the universe,” said Dr. Michael Werner, project scientist for Spitzer at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “These papers report the earliest results, so the best is yet to come.”

In the latest Antennae galaxies study, Spitzer uncovered a new generation of stars at the site where the two galaxies clash.

“We theorized that there were stars forming at that site, but we weren’t sure to what degree,” said Dr. Zhong Wang, lead author of the new paper and an astronomer at the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. “Now we see that the majority of star-forming activity in both galaxies occurs in the overlap regions where the two meet.”

The Antennae galaxies are a classic example of a galactic merger in action. These two spiral galaxies, located 68 million light-years away from Earth, began falling into each other around a common center of gravity about 800 million years ago. As they continue to crash together, clouds of gas are shocked and compressed in a process thought to trigger the birth of new stars. Astronomers believe that the two galaxies will ultimately merge into one spheroidal-shaped galaxy, leaving only hints of their varied pasts.

Galactic mergers are common throughout the universe and play a key role in determining how galaxies grow and evolve. Our own Milky Way galaxy, for example, will eventually collide with our closest neighbor, the Andromeda galaxy.

Previous images of the Antennae taken by visible-light telescopes show striking views of the swirling duo, with bright pockets of young stars dotting the spiral arms. At the center of the galaxies, however, where the two overlap, only a dark cloud of dust can be seen. In the new false-color Spitzer image, which has been combined with an image from a ground-based, visible-light telescope to highlight new features, this cloud of buried stars appears bright red. The visible-light information, on the other hand, is colored blue and indicates regions containing older stars. The nuclei, or centers, of the two galaxies are white.

“This more complete picture of star-formation in the Antennae will help us better understand the evolution of colliding galaxies, and the eventual fate of our own,” said Dr. Giovanni Fazio, a co-author of the research and an astronomer at the Harvard-Smithsonian Center for Astrophysics.” Fazio is principal investigator for the infrared array camera on Spitzer, which captured the new Antennae image.

JPL manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. JPL is a division of Caltech. Spitzer’s infrared array camera was built by NASA Goddard Space Flight Center, Greenbelt, Md.

Information about Spitzer can be found at http://www.spitzer.caltech.edu.

Original Source: NASA/JPL News Release

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Gemini Sees Galaxies in a Royal Rumble

A stunning image released today by the Gemini Observatory captures the graceful interactions of a galactic ballet, on a stage some 300 million light years away, that might better be described as a contortionist’s dance.

The galaxies, members of a famous troupe called Stephan’s Quintet, are literally tearing each other apart. Their shapes are warped by gravitational interactions occurring over millions of years. Sweeping arches of gas and dust trace the interactions and possible ghost-like passage of the galaxies through one another. The ongoing dance deformed their structures while spawning a prolific fireworks display of star formation fueled by clouds of hydrogen gas that were shocked into clumps to form stellar nurseries.

This unprecedented image of the cluster provides a unique combination of sensitivity, high resolution and field of view. “It doesn’t take long to reach an incredible depth when you have an 8-meter mirror collecting light under excellent conditions,” said Travis Rector of the University of Alaska, Anchorage who helped obtain the data with the Gemini North Telescope on Mauna Kea. “We were able to capture these galaxies at many different wavelengths or colors. This allowed us to bring out some remarkable details in the final color image that have never been seen before in one view.”

One striking element of the image is a collection of vibrant red clumps that mark star-forming regions within a galaxy called NGC 7320. Although its relation to the other galaxies in the cluster has been the subject of some controversy, most astronomers now think that the galaxy leads a relatively tranquil existence in the foreground, safely isolated from the violent quarrels of the more distant cluster.

Spectroscopic data show that NGC 7320 has an apparent velocity away from us of about 800 kilometers per second. In contrast, the rest of the group is being carried away from us by the expansion of the universe at over 6,000 kilometers per second. Using current models for the expanding universe, this would put the bulk of the cluster almost 8 times farther away from us than NGC 7320.

The vivid red patches scattered across the spiral arms of NGC 7320 in the new Gemini image provide a dramatic illustration of how these differing apparent velocities can impact our view. NGC 7320 and the other cluster galaxies have regions of intense star formation indicated by glowing clouds of hydrogen gas called HII regions. These areas appear distinctly red because a selective filter was used which only passes a special color of red light, called hydrogen alpha, that is produced in the HII regions. In the higher-velocity members of the cluster, prominent HII clumps dominate around the two closely interacting central galaxies but they do not appear red in the image. In these galaxies, the HII glow was Doppler-shifted beyond the range of the selective filter, and was therefore not detected.

The interacting members of Stephan’s Quintet appear destined to continue their dance for millions more years. Eventually, this dance will probably cause some of the galaxies in the cluster to completely lose their current identity, combining into even fewer objects than we see today.

Stephan’s Quintet was discovered in 1877 by the French astronomer Edouard Stephan using the Foucault 80-centimeter reflector at the Marseilles Observatory. The cluster is listed in the Hickson Compact Group Catalog as number 92. It has been studied extensively at all wavelengths including imaging by the Hubble Space Telescope. Recent observations of star cluster formation near Stephan’s Quintet with Gemini can be found here.

Original Source: Gemini News Release

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NASA Assesses the Damage From Frances

NASA teams are surveying the Kennedy Space Center (KSC) for damage caused by Hurricane Frances. Initial assessments show KSC weathered the storm fairly well. There are no reports of any injured KSC workers, and there does not appear to be damage to the Space Shuttles Discovery, Atlantis, and Endeavour.

“Our initial feeling is we dodged a real bullet,” said Kennedy Space Center Director Jim Kennedy. “Even though this was the worst storm ever to hit KSC, I feel very fortunate.”

KSC will remain closed Tuesday for most employees. Workers who need to report to work will be notified. A more detailed damage assessment is expected Tuesday.

The most serious damage reported so far is to the center’s landmark structure, the Vehicle Assembly Building (VAB), and to the facility that manufactures Space Shuttle Thermal Protection System tiles and blankets.

Sustained wind of more than 70 mph was recorded during the storm. Approximately 1,000 panels were blown off the VAB. In some places, exterior panels and underlying sub-panels are missing, leaving the interior of the building exposed to the elements. There are several holes, including one estimated to be 50 feet by 50 feet, in the building. Emergency operations personnel have not entered the VAB, as several loose panels are still hanging from the building and present a safety hazard.

The KSC Space Shuttle tile and blanket facility’s roof is partially torn off, and there is significant wall damage. Damage to the facility and its effect on the Space Shuttle Return to Flight effort is not yet known. The building housing International Space Station hardware and modules appears to be in good shape. KSC was powered down last week as Frances approached. Emergency operations teams are working to restore electricity and phone service to the center. NASA will provide new information as available.

Original Source: NASA News Release

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Final Helios Report Released

The board that investigated the loss of the remotely operated Helios Prototype aircraft during a test flight last summer released its final report today.

The board determined that the mishap resulted from the inability to predict, using available analysis methods, the aircraft?s increased sensitivity to atmospheric disturbances such as turbulence, following vehicle configuration changes required for the long-duration flight demonstration.

The Helios Prototype aircraft involved in the mishap was a proof-of-concept solar electric- powered flying wing designed to operate at high altitudes for long duration flight. The failure occurred during a flight from the U.S. Navy?s Pacific Missile Range Facility (PMRF) on the Hawaiian island of Kauai on June 26, 2003.

The propeller-driven aircraft had been flying under guidance of ground-based controllers from AeroVironment, Inc., of Monrovia, Calif., the plane?s builder and operator, with assistance from NASA Dryden Flight Research Center personnel. The aircraft was destroyed when it sustained structural failure and fell into the Pacific Ocean. No other property damage or any injuries occurred as a result of the mishap.

The lightweight, highly flexible flying wing took off at 10:06 a.m. local time. At 10:22 and 10:24 a.m., the aircraft encountered atmospheric turbulence, typical of conditions expected by the test crew, causing abnormally high wing dihedral (upward bowing of both wingtips). Unobserved mild pitch oscillations began, but quickly diminished, according to post-test data analysis.

At about 10:36 a.m., the aircraft again experienced normal turbulence and transitioned into an unexpected, persistent high wing dihedral configuration. As a result, the aircraft became unstable, exhibiting growing pitch oscillations. Airspeed deviated from the normal flight speed, with the deviations rapidly increasing with every cycle of the oscillation. The aircraft?s design speed was subsequently exceeded. The resulting high dynamic pressures caused the wing leading edge secondary structure on the outer wing panels to fail and the solar cells and skin on the upper surface to rip off. The remotely piloted aircraft came down within the confines of the Pacific Ocean test range, northwest of PMRF.

?The mishap underscores our need to assess carefully our assumptions as we push the boundaries of our knowledge,? said Dr. Victor Lebacqz, Associate Administrator for NASA?s Office of Aeronautics. ?It should not, however, diminish the significant progress AeroVironment and NASA have made over the past 10 years in advancing the capabilities of this unique class of aircraft on many successful flights, including Helios’ record setting flight to just under 97,000 feet altitude in August 2001. It is important that we learn from this experience, and apply the board’s findings and recommendations to help ensure the payoffs of such vehicles are fully realized.?

The report is available on the Web at: http://www.nasa.gov/pdf/64317main_helios.pdf

Original Source: NASA News Release

Posted on by Fraser Cain

Astronauts Complete Final Spacewalk

Smoothly and ahead of schedule, Expedition 9 Commander Gennady Padalka and NASA Science Officer Mike Fincke completed the fourth and final spacewalk of their six-month mission today. Padalka and Fincke spent five hours, 21 minutes outside completing mainenance tasks and installing antennas to prepare for the initial arrival of a new European cargo ship next year.

Wearing Russian Orlan spacesuits, Padalka and Fincke began the spacewalk at 11:43 a.m. CDT, emerging from the Pirs airlock affixed to the Zvezda Service Module. It was Padalka?s sixth career spacewalk and the fourth for Fincke, all of his conducted during this expedition. The spacewalk was supervised by Russian flight controllers at the Mission Control Center in Korolev, outside Moscow.

After setting up tools and tethers, Padalka and Fincke quickly went to work. On the Zarya module, they replaced a pump control panel that measures the module’s coolant levels. They then installed a series of tether guides on four handrails. The guides are intended to prevent future spacewalkers? tethers from becoming snagged.

As the Station moved into orbital darkness, the spacewalkers took a rest break. During the break, flight controllers in Houston collected data on the orientation of the outpost. The information will help determine if the cooling systems of the Russian spacesuits contribute to changes in the Station?s orientation. Throughout today’s spacewalk, the Station remained in predicted orientations. No unanticipated measures were needed to maintain its stability.

Padalka and Fincke spent two and a half hours on the exterior of Zvezda, installing three communications antennas at its aft end. Those antennas, along with other equipment installed during an Aug. 3 spacewalk, will be used next year. They will guide the European Space Agency?s unpiloted Automated Transfer Vehicle (ATV), the “Jules Verne” cargo ship, to its maiden docking with the Station. Three more ATV navigation antennas will be installed by the next Station crew, Expedition 10, in February. The Expedition 11 crew will install ATV communications gear inside Zvezda as well.

Padalka and Fincke returned to Pirs and installed protective handrail covers at one of the two airlock hatches. The covers will ensure tethers do not inadvertently wrap around the handrails.

Fincke also photographed a suitcase-sized tray of Japanese commercial experiments mounted on Zvezda to measure the effect of micrometeoroids on a variety of materials. Called Micro-Particle Capturer and Space Environment Exposure Devices, they were installed on Zvezda almost three years ago.

With their work done, Padalka and Fincke returned to the airlock and closed the hatch at 5:04 p.m. CDT. The spacewalk was the 56th in support of Station assembly and maintenance and the 31st based from the Station. In all, Padalka and Fincke have spent 15 hours and 45 minutes outside the Station during their four spacewalks together. To date, spacewalkers have spent more than 338 hours outside the Station for maintenance and assembly work.

For information on the crew’s activities aboard the Space Station, future launch dates, as well as a list of opportunities to see the Station from anywhere on the Earth, visit:

http://spaceflight.nasa.gov/

For details on Station science operations provided by the Payload Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Ala., visit:

http://scipoc.msfc.nasa.gov/

Original Source: NASA News Release